CHRONIC OSTEOMYELITIS

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FUNCTIONAL OUTCOME AND RELAPSE RATES FOLLOWING SURGICAL DEBRIDEMENT IN

CHRONIC OSTEOMYELITIS

Dissertation submitted to the Tamil Nadu Dr. M.G.R Medical University in partial

fulfillment of the requirement for the M.S Degree Examination

Branch II (Orthopaedic Surgery)

May 2020

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CERTIFICATE

This is to certify that the dissertation titled “ FUNCTIONAL OUTCOME AND RELAPSE RATES FOLLOWING SURGICAL DEBRIDEMENT IN CHRONIC OSTEOMYELITIS ” is a bonafide work of Dr. Samuel Santhosh S, in the

Department of Orthopaedic Surgery, Christian Medical College and Hospital, Vellore in partial fulfillment of the rules and regulations of the Tamil Nadu Dr. M.G.R

Medical University for the award of M.S Degree Branch II (Orthopaedic Surgery), under the supervision and guidance of Prof. Dr. Manasseh Nithyananth during the period of his post-graduate study from April 2017 to May 2020. This consolidated report presented herein is based on bonafide cases, studied by the candidate himself.

GUIDE:

Prof. Dr. Manasseh Nithyananth, M.S.Orth,

Professor of Orthopaedics, Orthopaedics Unit –I,

Department of Orthopaedic Surgery, Christian Medical College and Hospital,Vellore.

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CERTIFICATE

HEAD OF THE DEPARTMENT:

Prof. Dr. VINOO MATHEW CHERIAN D.Orth, M.S.Orth, Dip.N.B.

Professor& Head, Department of Orthopaedics, Christian Medical College & Hospital,

Vellore.-632004

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CERTIFICATE

PRINCIPAL

Dr. Anna Pulimood, Principal, M.D (Path), PhD

Christian Medical College & Hospital Vellore-632004.

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DECLARATION

I hereby declare that this dissertation titled “FUNCTIONAL OUTCOME AND RELAPSE RATES FOLLOWING SURGICAL DEBRIDEMENT IN CHRONIC OSTEOMYELITIS” was prepared by me in partial fulfillment of the regulations for the award of the M.S Degree (Final) Branch II (Orthopaedic Surgery) of the Tamil Nadu Dr. M.G.R Medical University, Chennai towards examination to be held in May 2020. This has not formed the basis for the reward of any degree to me before and I have not submitted this to any other university previously.

Dr. Samuel Santhosh S.,

Post Graduate Registrar (M.S Orthopaedics), Department of Orthopaedics,

Christian Medical College - Vellore, Vellore-632002

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ACKNOWLEDGEMENTS

I wish to express my sincere gratitude to my guide and mentor Dr. Manasseh

Nithyananth, Professor of Orthopaedics, for enabling me to choose and analyse a topic that is of significant clinical value and is a challenge to the present and future

generations of Orthopaedic Surgeons. I would like to thank Sir for all the help and support that was extended to me during my entire stay in CMC.

I thank God for giving me this opportunity for being a part of this leading institution I wish to express my sincere gratitude to my wife, my parents and all my friends who played a vital role in helping me and encouraging me to complete this dissertation.

I am eternally grateful to all my teachers for the guidance and encouragement throughout my entire Post graduate program. I wish to thank my teachers for demonstrating and sharing their experiences and insights regarding surgeries and patient care. I wish to thank Dr. Vernon N. Lee, Dr. Vinoo M. Cherian, Dr. Manasseh N., Dr. Kenny S. David, Dr. Venkatesh K., Dr. Rohit Amritanand, Dr. V.T.K. Titus, Dr. Pradeep M. Poonnoose, Dr. Anil T. Oomen, Dr. Alfred Job Daniel, Dr. Thilak Jepegnanam, Dr. P.R.J.V.C Boopalan, Dr. Vrisha Madhuri, Dr. Thomas Palocaren, Dr. Abhay, Dr. Binu, Dr. Anil Matthew, Dr. Sam C. Raj and Dr. Kiran Sasi for teaching and guiding me throughout my program.

I wish to thank my all my junior teachers Dr. Dan Barnabas, Dr. Sandeep Albert, Dr.

Jeremy Bliss, Dr. VJ Chandy, Dr. Jerry George, Dr. Hariharan, Dr. Sumant Samuel, Dr. Abel Livingston, Dr. Kaushik Bhowmick, Dr. Ajit Joseph, Dr. Chandrasekhar, Dr.

Bhim and Dr. Roncy for their guidance and imparting skills to operate and their willingness to teach me throughout.

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I would like to thank my wife, Dr.Preethi Elizabeth, my parents, Dr. Sathyaprakash and Dr. Sobana Sathyaprakash and my in-laws, Dr.Kuryan George and Mrs.Meera Kuryan for being pillars of support throughout the process of preparing this

dissertation and helping me with constant encouragement till completion. I would also sincerely like to thank my special friends, batchmates and interns especially, Dr.

Jackwin Sam Paul, Ms.Chriset Jeyaraj, Ms. Faith M. John, Ms. Reshma George, Mr.

Ananth John, Mr. Kevin Pandian, Ms. Nimmy Thomas, Ms. Nalina Arunkumar and Mr. Augustine J. Paul for tirelessly helping me in the data collection and data entry process, as well as being massive sources of support throughout times of difficulty.

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TABLE OF CONTENTS

1. INTRODUCTION ……… 10

2. AIM AND OBJECTIVES………. 13

3. REVIEW OF LITERATURE……… 15

 BACKGROUND……… 16

 EPIDEMIOLOGY………... 19

 PREDISPOSING FACTORS……….. 20

 PATHOPHYSIOLOGY……….. 21

 CLASSIFICATION……… 30

 DIAGNOSIS……… 35

 MANAGEMENT………. 39

4. MATERIALS AND METHODS……… 45

5. RESULTS ……….. 72

6. RADIOGRAPHS ……… 98

7. DISCUSSION ………. 102

8. STRENGTHS AND LIMITATIONS……..……… 108

9. CONCLUSION ………... 111

10. BIBLIOGRAPHY……….. 113

11. ANNEXURES ……… 117

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INTRODUCTION

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Chronic osteomyelitis has always been one of the most challenging conditions to treat in the field of orthopaedics. Due to its long duration of treatment and high chances of recurrence even after apparently successful treatment, it requires a multidisciplinary approach for management as well as precise, targeted follow-up guidelines to detect signs of infections early. Over the last few decades, the common aetiology of chronic osteomyelitis has gradually changed from haematogenous, which was previously the predominant cause, but recently, implant-related infections or post-traumatic cause have been reported as the most common cause for chronic osteomyelitis. The

emotional and physical strain, and the financial burden on patients suffering from this condition has been significantly affecting the lives of millions all over the world, especially in developing countries. Recurrence of infection is a common occurrence associated with chronic osteomyelitis and this can be attributed to various patient/

host-related or surgeon-related factors.

Successful management involves a multidisciplinary team approach, associating with other specialists’ such as radiologist, microbiologist, plastic surgeons and infectious diseases. The mainstay being a thorough surgical debridement with precise pre-

operative planning, appropriate antibiotic management is also required for eliminating infection.

Considerable number of studies and recent research continue to abound in the diagnosis and management options of osteomyelitis. However, there is only sparse literature focusing on the functional outcome and the relapse rates following surgery.

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The purpose of this study is to focus on the lacuna of present knowledge related to the rate of relapse following surgery and also to assess the functional outcome of patients following surgical debridement.

We devised a study to prospectively follow up on patients at regular intervals following surgery and look into the frequency of relapse to assess the functional outcome of all patients on review. For ease of statistical analysis, they were grouped on the basis of variables like pre-op MRI, specific diagnosis and so on, with the exposure of the study being surgical intervention at a tertiary care centre, CMCH Vellore. According to the limited literature, there is a wide range defined for

relapse/recurrence rates in chronic osteomyelitis. However, the most frequent range mentioned is about 20-30% even after antimicrobial therapy and recent surgical advances.(1)

This study also seeks to report the rate of re-infection or in other words, relapse of chronic osteomyelitis following surgical debridement, as well as to assess and compare the functional outcome at regular follow-up visits.

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AIMS AND OBJECTIVES

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AIMS

 To study the results and functional outcome after surgery for chronic osteomyelitis in long bones.

 To study the rate of relapse in chronic osteomyelitis.

OBJECTIVES

1. To assess the functional outcome in patients with long bone chronic osteomyelitis who have undergone surgical debridement.

2. To calculate the relapse rates in patients with chronic osteomyelitis who have undergone treatment in Orthopaedics department CMCH between Jan 2017 to Jun 2019.

3. To compare the relapse rates between patients who had a pre-operative MRI and those who have not had a pre-operative MRI.

4. To study the aetiology/ causative organism involved and the duration of antibiotics Administered, for chronic long bone osteomyelitis.

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REVIEW OF LITERATURE

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BACKGROUND

It is a challenge to manage chronic osteomyelitis of long bones, especially in adults and often a multidisciplinary approach is required for the elimination of infection and for achieving adequate function of the limb involved. There has been a steady increase in the incidence of chronic osteomyelitis especially in the adult population, despite improvements in preventive, diagnostic and treatment strategies due to the long disease course, difficult early diagnosis and high disability rate.

Osteomyelitis is heterogeneous in its pathophysiology, clinical presentation, and management. The disease/condition/inflammation can be due to either contiguous spread of infection from adjacent soft tissues and joints or haematogenous seeding, or direct inoculation of bacteria into the bone as a result of trauma or surgery(2,3). The infection may be restricted only to the bone tissue or may involve the surrounding soft tissues.

The diagnosis and treatment of chronic osteomyelitis have improved significantly over the years, and a systematic classification and staging system helps in defining

treatment plans.

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HISTORY OF OSTEOMYELITIS

Infection following bony fracture has been identified since the time of Hippocrates (460 - 370 BC). However, it was not until the latter half of the eighteenth century that the clinical picture of acute haematogenous osteomyelitis neared completion. William Bromfeild recorded his findings of the disease in 1773, as bone “may” become

carious, first in its internal parts and that from external injury. He labelled the

condition, “ Abcessus in medulla”, recommending that “we need not be too early to let it out when we are assured of matter being under the periosteum”. This

information was further fortified in 1831, when Nathan Smith, Professor of Surgery at Yale University, noticed that “a majority of patients survive the attack, albeit with long confinement, protracted suffering and great emaciation. In a few cases, however, the disease proves fatal.” Smith thereby deemed the condition necrotic, seeing as it involved localised degeneration within the bone. The actual term ‘osteomyelitis’

however, owes its coinage to Auguste Nelaton(4) who introduced the term in 1844.

Before the historic introduction of penicillin by Howard W Florey, Ernst Chain and their fellow scientists, the treatment of acute osteomyelitis was premised upon specific principles as put forth by American surgeon, Winnett Orr (1877 – 1956). These

principles was a combination of revolutionary concepts as well as conventional ideas.

Orr’s goal was to helm a single primary operation, whereby all dead and diseased tissue could be removed entirely. Such an operation was performable at all stages of the illness, regardless of its nature – that is, whether acute or chronic. In order to increase visibility on all diseased areas of the bone, Orr favoured sizeable incisions.

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Infected portions of tissue were then excavated with ‘saucerization’ of the cavity.

Vaseline gauze was used to dress the otherwise exposed wound, and the limb was plastered (in a neutral or functional position) to effect immobilisation. Secondary infection was limited by fewer changes of dressings and plasters; the wound was only inspected in case of pain and/or fever. Orr’s method hinged mainly on the tissues’

own defence mechanism and discouraged use of antiseptics. In later stages, braces were necessitated. Dressings and plasters were changed as infrequently as possible in an effort to decrease secondary infection. Pain and fever provided the main indication for inspection of the wound. No antiseptics were used, as he relied on the natural defence mechanisms of the tissues. Braces were required in the later stages.(5)

As theories abounded on the ways to address the disease, a major leap in its diagnostic stage was achieved through the use of X-rays. Discovered by Wilhelm Roentgen in 1896, X-rays tremendously widened the scope of understanding acute osteomyelitis.

However, in its early stages, the actual changes in the bones could not be deduced through X-rays. It was only with the help of a more recent, clearer understanding that the soft tissue changes came to be noticed.

The first paper on osteomyelitis in the Journal of Bone and Joint surgery, in February 1948, was from the Royal Hospital for Sick Children in Glasgow, and it illustrates the benefits of penicillin which had gradually become available in the 1940s. It is also mentioned that there had been little change in the incidence in Glasgow since the beginning of the century, and that before the introduction of chemotherapy in the form of sulphonamides, the mortality remained high. Most cases were admitted with

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toxaemia, and treatment of the local bony focus had little effect in arresting the disease. Surgical treatment included incision of soft-tissue abscesses, immobilisation, drilling and guttering, and even amputation.

EPIDEMIOLOGY

There has been a steady increase in the incidence of chronic osteomyelitis, despite the various advances in operative management and systemic antibiotics. The complex course of the disease, high recurrence rates and the cost of treatment involved pose a heavy burden on the patient and relatives.The clinical presentation may vary

depending on geography, time and pathogenetic differences.Over time, a clear shift has occurred from predominately haematogenous osteomyelitis several decades ago, to an escalated prevalence of chronic osteomyelitis that results from trauma, implant infection, and diabetes.(6)

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PREDISPOSING FACTORS

Many intrinsic and extrinsic factors have been reported as risk factors for the development of chronic osteomyelitis(7). Other factors include:

malnutrition, diabetes mellitus, chronic steroid use, peripheral vascular disease, hypotension, malignancy, smoking , alcoholism, systemic or local

immunocompromised state, IV drug abuse and decubitus ulcers with secondary seeding .(8),(9)

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PATHOPHYSIOLOGY

Osteomyelitis due to local spread from a contiguous contaminated source of infection follows trauma, bone surgery, or joint replacement. It implies an initial infection that gains access to bone. It can occur at any age and can involve any bone. In this group, identification of patients with a foreign-body implant is important, both because of their high susceptibility to infection and because of treatment challenges.

Osteomyelitis, secondary to vascular insufficiency, occurs predominantly in people with diabetes and in almost all cases, follows a foot soft-tissue infection that spreads to the bone. This disease entity has several important contributing factors: vascular compromise of bone and soft-tissue, the metabolic changes in diabetes and peripheral neuropathy.

Haematogenous osteomyelitis is seen mostly in pre-pubertal children and in elderly patients and is characterised by nidation of bacteria within sometimes only slightly injured bone, presumably seeded by bacteria not apparent, but present in the blood.

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Acute osteomyelitis develops over several days or weeks, as opposed to chronic osteomyelitis, which is somewhat broadly defined as long-standing infection that evolves over months or even years, characterised by the persistence of

microorganisms, low-grade inflammation, and the presence of dead bone (sequestrum) and fistulous tracts (figure 1).(10)

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MECHANISM OF BONE DISEASE

In an acute osteomyelitic bone, a microscopic examination reveals acute suppurative inflammation in which bacteria or other microorganisms are embedded. A

combination of inflammatory factors and leucocytes themselves contribute to tissue necrosis and destruction of bone trabeculae and bone matrix.

The vascular channels are obliterated by the inflammatory process, and the resulting ischaemia contributes to bone necrosis. These segments of bone with vascular

compromise can separate from the unaffected bone to form sequestra and can continue to harbour bacteria despite antibiotic treatment.

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The development and progression of the disease involves three major stages which include bacterial contamination and adhesion – expression of virulence factors, followed by infection and subsequent chronicity. Predisposing factors of the patient have a vital role to play at various levels (8).

Healthy bone has a high threshold for infection. The presence of foreign bodies, contamination, or the presence of bone necrosis, as well as other host related or environmental factors at the particular site play an important role to allow the colonization of bacteria and eventually may lead to infection.

Trauma or surgery can produce devitalised bone fragments. It has also been proven through experimental studies that ischaemia is the other most potent bone necrotising factor. Patchy ischaemic bone necrosis occurs when the infective process occludes the vascular tunnels, which creates an ideal culture medium for bacteria and at 48 hours, abscesses are formed. A sequestrum develops within 8 days.

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Most commonly isolated microorganisms in osteomyelitis are related to age and susceptibility factors (adapted from Lew, Waldvogel, 2004; Brook, 2008; McNally, Nagarajah, 2010;Chihara, Segreti, 2010; Jorge et al., 2010;Zimmerli, 2010; Eid, Berbari 2012)

Table 1: Microorganisms isolated from patients with chronic osteomyelitis and their clinical manifestations

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BACTERIAL CONTAMINATION AND ADHESION. DEVELOPMENT OF INFECTION

(11) Figure 2.Pathogenesis of chronic osteomyelitis

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Bacteria may reach the bone via the circulation, by direct inoculation caused by trauma, surgery or by direct spread from an adjacent foci of infection. Irrespective of the route of spread, bacteria must adhere to bone components and propagate to express virulence and eventually cause infection. Bacteria adhere to each other and are

covered in a layer of fibrinogen which protects them from host defence mechanisms and antibiotics (12). But this alone is not adequate to describe how bacteria adhere to bone matrix. Staphylococcus spp. express high affinity receptors (adhesins) for fibronectin, collagen and laminin.

Fibronectin, a glycoprotein found in many body fluids and connective tissue matrices, plays a vital role in the pathogenesis of chronic osteomyelitis. The same glycoprotein has been shown to mediate bacterial adhesion to metal plates and screws. (10)

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CHRONICITY ASSOCIATED WITH AN IMPLANT

Persistence of bone infection results in chronic osteomyelitis. The diagram below defines the main factors responsible for the development of chronicity:-

Figure 3. Pathogenetic factors behind the chronicity of a bone infection. (9)

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The main pathology involved in chronic osteomyelitis associated with a foreign body such as plate and screws or joint replacement in Bacterial persistence due to increased virulence. In such cases, antimicrobial therapy alone is often unsuccessful, and the infection is cured only by thorough debridement of the necrotic bone and the removal of the implant. Southwood et al, performed an experiment using a rabbit model(with orthopaedic implant), found that only 50 organisms contaminating the operative site following a cemented hemiarthroplasty had resulted in infection, whereas 10 000 organisms were required to produce infection in the absence of a foreign body.(13)

Hence the presence of an implant in itself can predispose a patient to osteomyelitis.

ROLE OF HOST DEFENSE MECHANISMS:

Polymorphonuclear leucocytes (PMLs) extracted from tissue fluid surrounding a foreign body are unable to kill catalase positive S. aureus despite optimal

opsonisation. The same PMLs also exhibit a decreased production of superoxide and have lower content of enzymatic granules, an indication of impaired response to infection. This results in a PML population composed of exhausted cells, with lower granule content, and less killing capacity. Another similar study also demonstrated that the opsonisation of S. aureus in the presence of a foreign body is significantly reduced at 20 hours. Since S.aureus is mainly destroyed by opsonisation and subsequent phagocytosis by PMLs, the host defence defects mentioned above are responsible for the development of chronic osteomyelitis associated with internal fixation or joint replacement.(14)

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Bacteria have been shown to persist within glycocalyx-enclosed microcolonies which are adherent to the bone as well as prosthetic devices in cases of osteomyelitis.(15)

Biofilms are typically composed of cells embedded in a highly hydrated

polysaccharide matrix with nucleic acids and proteins throughout. These biofilms are associated with the refractory nature of chronic infections such as osteomyelitis. It has been reported that the concentrations of antimicrobial agents required for the eradication of bacteria in biofilms are more than 50 to 1000 times higher than those needed for killing of the free-floating planktonic cells. Such levels of antibiotics can be toxic to the patient.

In bones, there is further complication with the reduced penetration into infected and ischaemic areas, leading to suboptimal antibiotic concentrations. The reason for the reduced ability of antimicrobial agents to eradicate these infections is the reduced antibiotic penetration and the very slow growth rate and differential upregulation of stress response genes by cells within the biofilm.

Chronic osteomyelitis may present as an intermittent or recurrent disease and generally has variable durations of quiescence.

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CLASSIFICATION

There are two well-known classification systems for osteomyelitis, the Cierny-Mader, and the Waldvogel. Recently, new classification systems have been proposed which are designed to be more specific to modern diagnostics and management approaches of osteomyelitis. The important considerations used in the new systems include bone involvement, antimicrobial resistance patterns of causative microorganisms, the host status and the need for soft tissue coverage.

Tenderness, effusion, increased warmth, pain with motion, and drainage on the area of the affected bone are signs and symptoms of chronic osteomyelitis.

Trauma has recently proven to be a major risk factor for osteomyelitis(16). Open fractures are at high risk of transcutaneous contamination of bacteria (17). The

pathophysiology of traumatic osteomyelitis depends on bones involved, characteristics of the initial injury, and host condition (18).

The Waldvogel classification is based on the aetiology of osteomyelitis. It categorises the infection into 3 types, depending on the pathophysiologic mechanism:-

haematogenous osteomyelitis; implant related, contiguous focus osteomyelitis from trauma, surgery or soft tissue spread; and also includes vascular insufficiency osteomyelitis often seen in diabetes mellitus.(19)

Of the other classification systems devised to evaluate osteomyelitis, the Cierny- Mader classification system remains the most clinically relevant.

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CIERNY AND MADER CLASSIFICATION OF CHRONIC OSTEOMYELITIS

Table 2. Cierny-mader classification

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The Cierny-Mader classification system, stratifies hosts into 3 categories (A-C) based on physiologic co-morbidities and designates 4 anatomic stages of infection (1-4).

This system plays an important role in preoperative planning for the extent of surgical debridement, as well as antibiotic therapy. The following diagrammatic

representation of the anatomic types also shows the surgical option for the associated anatomic type of chronic osteomyelitis;-

Figure 4. A graphic depiction of the four anatomic types of

osteomyelitis matched with a surgical and reconstruction format for each.

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MEDULLARY OSTEOMYELITIS – TYPE I

In type I osteomyelitis, the biofilm nidus is confined to the endosteum as dense scar, infarcted marrow, dead bone, or a medullary implant. Soft-tissue involvement is usually reactive in nature and responsive to removal of the nidus and a short course of antibiotics.

SUPERFICIAL OSTEOMYELITIS – TYPE II

Type II osteomyelitis is a true form of the contiguous-focus osteomyelitis described by Waldvogel et al. in 1970. Here, the nidus is an exposed, bony surface at the base of a chronic, open wound. The medullary contents are not involved.

LOCALIZED OSTEOMYELITIS – TYPE III

The hallmark of type III osteomyelitis is presence of a full-thickness, cortical sequestrum (as shown in the figure above). The canal is involved (type I pattern), there may be a soft-tissue deficit (type II pattern), and indwelling hardware is commonly present. Examples would include an infected fracture union with plate fixation and presence of a sequestered, butterfly fragment. To distinguish this from a type IV osteomyelitis, the involved bony segment will still be stable following a complete debridement.

DIFFUSE OSTEOMYELITIS –TYPE IV

Diffuse Osteomyelitis (Type IV) is a permeative, through-and-through type of infection combining the characteristics of types I, II, and III osteomyelitis with the additional feature of instability. These lesions are either intrinsically unstable (i.e., an

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infected non-union) or rendered unstable with debridement (i.e., a peri-prosthetic, total joint infection, or a haematogenous osteomyelitis requiring diaphysectomy for cure).

The host staging included in this system combines the health status of the patient with the physical impact of disease (on function) into a physiologic host class: healthy patients are designated as A-hosts, and patients with co-morbidities affecting their response to stress, trauma or infection are classified as B-hosts. B-hosts are prone to high incidence of metabolic deficiencies, immune compromise, and episodes of

bacteraemia, wound slough, and excessive bleeding and hence are at risk for treatment failure. If the risks and/or morbidity of treatment outweigh the benefits, the patient is classified a C-host and not offered definitive treatment.

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DIAGNOSIS

Patients with chronic osteomyelitis can present with a spectrum of signs and symptoms which may not always be obvious, but a detailed history and a thorough physical examination along with imaging is pivotal for deciding the best treatment modality for that patient/individual. It is also important to elicit predisposing factors or parameters such as diabetes, vasculopathy, invasive procedures, or injection drug use, etc. Diagnosis is based on clinical examination, laboratory studies, microbiology, imaging and histopathology.

There is no definitive criteria proposed for the diagnosis of osteomyelitis and this makes it difficult to compare different approaches to surgical and medical

management.(20)

The variety of osteomyelitic symptoms includes localized bone and joint pain, erythema, swelling, fevers, night sweats, and a draining sinus. Physical examination includes not only the site of infection but adjacent joints, muscles, and possible donor flap sites (in case of previous surgeries). Laboratory tests’, such as C-reactive protein, erythrocyte sedimentation rate and total leukocyte count can be helpful in diagnosis.

C-reactive protein is also useful for monitoring response to therapy.

MICROBIOLOGY

There have been many studies conducted in the past directed towards achieving a

‘gold standard’ specimen for accurate microbiological diagnosis which is essential for successful treatment. Yet, most of these studies have had certain methodological flaws which makes it is difficult to draw definitive conclusions and hence it is generally

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accepted to obtain soft tissue which causes suspicion of infection and adequate dead bone for further microbiological study to isolate the causative organisms.(21)

Patient goals for post-treatment function and outcome should also be understood.

Relapse

Patients included in the analysis were classified as either ‘cure’ or ‘relapse’ based on follow- up information. ‘Relapse’ was defined as infection occurring again at the same site from which it had been eliminated previously and which was treated specifically with another course of antibiotics or surgery. The duration of relapse is indefinite. Even after administration of antibiotics long term and extensive surgical debridement, recurrence can occur years after apparently successful treatment. The follow-up period is still debatable, but most surgeons agree that it should be as long as five years, as incidence of recurrence remains high.

IMAGING IN OSTEOMYELITIS

Radiographic changes are not evident for up to two weeks after the disease process begins and can be difficult to interpret. Early radiographs show haziness and loss of density of the affected bone, and may also show soft tissue swelling, periosteal thickening and/or elevation and focal osteopenia. The lytic changes which are diagnostic for osteomyelitis usually occur later once the infection is established. Radionucleotide scans, Magnetic resonance imaging and CT may be required to determine the extent of the infection. Radionucleotide scans may be positive in the initial period of infection as early as two days after the onset of infection, but are not highly specific. Impaired blood supply may reduce the effectiveness of technetium Tc 99 polyphosphate scans, and gallium scans do not distinguish well between bone and soft tissue

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inflammation. MRI has very high sensitivity and specificity for osteomyelitis (88% and 93%, respectively) compared with radioisotope scans (61% and 33%, respectively). Pugmire, Shailam, and Gee 2014

Acute:

 Medullary space

 Fat is replaced by oedema, so:

 Low signal on T1

 High signal on T2,STIR or Fat suppressed sequences

 Possible cortical disruption

 Wide transition zone

 Soft tissue : Oedema, abscess , sinus tract, ulcer and cellulitis

 Chronic:

 Low signal on T1 and T2

 Bone sclerosis with cortical thickening

 Narrow transition zone

 Sequestra on gadolinium enhanced T1

MRI is both sensitive for the early detection of osteomyelitis and can also help in the precise depiction of the extent of disease. It also gives a detailed picture of abscess or soft-tissue extension without the complications associated with radiation exposure. MRI helps in the anatomic delineation of the medullary space, the cortical and periosteal changes from the soft

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tissue contrast for tracing oedema or fluid pockets. Pre-operative MRI helps the surgeon in the approach and planning which has been shown to limit the extent of surgical exposure and also reduce operative time. MRI does not have a major role in children as it involves long scan time and chances of motion artefacts which may need for sedation for the child.

Furthermore, MRI is contraindicated in individuals with metallic foreign bodies and certain types of implanted hardware. However, the importance of MRI in evaluating osteomyelitis is evident in recent clinical practice guidelines which emphasise that MRI is the imaging

modality of choice for the detection of osteomyelitis and infection involving the extra osseous soft tissues.

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MANAGEMENT OF CHRONIC OSTEOMYELITIS

The treatment of this disease requires a multidisciplinary approach and a long-term follow-up. The decision regarding the treatment modality of choice has to be made after carefully taking into account the host factors and the nature of the disease. The choice is between a palliative approach and a curative approach, on an

interdisciplinary basis, depending on what the patient can tolerate.

The curative approach to chronic osteomyelitis has the following goals:

● Arrest the infection

● Reduce pain

● Retain limb and function.

Antimicrobial treatment

The extent and degree of antibiotic penetration in bone tissues are reported as determining factors for successful treatment in osteomyelitis.(22) In turn, the penetration of an antibiotic into infected bone depends on its pharmacological

characteristics, status of soft tissues, the degree of vascularization, and the presence of foreign bodies.(23)

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Therapeutic regimens in acute and chronic infections

The success of treatment in osteomyelitis, especially in cases related to implants, depends on radical targeted surgical debridement and adequate and effective antibiotic therapy. Starting empirical antibiotics prior to surgery, at the time of induction has shown to prevent bacteraemia. However, it does not interfere with the positivity of tissue cultures obtained during the procedure. The duration of antibiotic therapy which is generally accepted is a minimum of four to six weeks but can vary from four weeks to six months as well. The choice of antibiotic should be adjusted based on the culture sensitivity of the specific organism. Acute infections can be treated initially with extensive surgical cleaning associated with antibiotic therapy lasting four to six weeks. Due to biofilm formation, the total duration of antibiotics spans three to six months.

Special antimicrobial – Rifampin

There is no specific antibiotic regimen that is standard for all. The ability of rifampin in eradicating slow-growing bacteria in biofilms is reported and this is vital for most organisms. Thus, addition of rifampin along with another drug with activity against S.

aureus is described in the literature, but this drug should not be used as monotherapy.

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SURGICAL TREATMENT

Although surgery is the only cure in almost all cases, it may not always be the best option for treatment. Thus, in order to decide treatment, a multidisciplinary approach should be adopted for patient assessment. The treatment of chronic osteomyelitis should include the following:

 Accurate microbiological diagnosis

 Improvement of the host’s defences

 Stabilization of underlying diseases

 Correct anatomical localization of bone involvement

 Adequate and appropriate antimicrobial therapy

 Surgical debridement of all devitalized tissue

 Soft tissue repair

 Bone reconstruction

 Rehabilitation

The surgical technique adopted would depend upon the extent of the bone

involvement. When vital structures such as vessels, tendons, nerves or bones are exposed, wound closure by any means is imperative, often requiring local flaps or complex microsurgical flaps which are located further away.

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The complete resection of all the devitalized tissues, followed by establishment of adequate blood flow, is essential for effective systemic antimicrobial therapy. A resection margin of 5 mm should be the general norm during debridement. The use of antibiotic-coated cement has also been described for filling the defect after adequate bone resection. The most commonly used antibiotic is vancomycin at a dosage of 2–4 grams per 40g of cement. Other antibiotics which are not thermolabile may also be used, due to the exothermic reaction of the polymethylmethacrylate.

Another approach is the use of vacuum-assisted closure, which has shown excellent results. Its careful and precise usage can significantly improve the condition of the soft tissue wound in terms of characteristics of vascularization, the granulation ability and texture, and reducing its size.

Dead-space management

Following debridement, the dead space created should be managed adequately while the infection is being treated. The surgical options of local muscle (rotational flap) or a free-muscle flap are commonly described in literature. The main factor that

determines the choice flap procedure is the size of the defect. For smaller defects with soft-tissue loss, fasciocutaneous free flaps are recommended as it reduces the

morbidity from the donor site. In case of a large dead space, a free-muscle flap is usually preferred, while in cases with major bone loss, a vascularized bone graft can be used, or composite grafts including bone, muscle, and/or skin can be used.

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Soft-tissue coverage

Microvascular free-muscle transfer is considered the gold standard for vascular soft- tissue coverage for soft tissue defects. Other options include local rotational muscle flaps. The timing of vascularized microsurgical procedure depends on various factors such as condition of remaining bone, surrounding soft tissue status etc. Doi et al and Rhomberg et al reported successful results following a single-stage procedure, while Dinh et al advocated a two-stage procedure.

Skeletal stabilization and management of skeletal defects

Skeletal stabilization is consider the norm for all Type 4 and some Type 3 Cierny- mader lesions, following excision of the devitalized bone. External fixation is universally accepted as the first stage procedure for stabilisation. In some cases, it converted into internal fixation after confirmation of infection control or elimination at the site. Paley and Herzenberg introduced the concept of antibiotic bone cement- impregnated intramedullary nails to achieve adequate stability and simutaneously offer local delivery of antibiotics.

Bone defects less than 6 cm can be treated with iliac crest or fibula (autologous) bone grafting. Larger defects are best treated with a help of an Illizarov ring fixator using the principle of distraction osteogenesis or vascularized bone graft typically taken from the fibula have also shown to be successful.

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Marsh et al reported a 100% cure rate at 1-year follow-up using the distraction osteogenesis technique although it is time-consuming, and needs meticulous care during the course of treatment.

The vascularized bone graft offers certain advantages, including providing autogenous cortico-cancellous grafts with intact blood supply. The mechanism of their

incorporation is different from other avascular grafts, as there is no necrosis or

resorption. The architecture, the mass and biomechanical strength of the vascularized graft is maintained, and they also have ability to hypertrophy. These can be obtained from the iliac crest, fibula and ribs and transferred with skin, fascia, and muscle to fill soft-tissue defects. The success rate of vascularized fibular grafts has been reported to be between 77% and 90%. Complications with the use of vascularized bone grafts include failure of the anastomosis, fracture of the graft, and donor-site morbidity.

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_____________________________________________________________________

MATERIALS AND METHODS

_____________________________________________________________________

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STUDY DESIGN

A Cohort study of patients who have had surgical debridement following chronic osteomyelitis or infected non-union of a single long bone was carried out to estimate relapse of osteomyelitis.

All patients older than 18 years of age with a minimum follow-up of 3 months were included in the series. Over the past two decades literature with regards to functional outcome and rates of reinfection following surgical debridement in chronic osteomyelitis has been sparse. In this study we would like to establish relapse rate and assess the functional outcome following surgery. The role of MRI in the preoperative planning was also compared.

Data regarding the patients who had followed up after surgery were obtained from the IP and OP registry and the functional outcome was assessed by standard questionnaire and clinical outcome scores.

The patients were then grouped on the basis of whether a pre-operative MRI had been done or not and comparison of relapse rates where done between the two cohorts.

The Data was collected from 353 patients with chronic osteomyelitis or infected non-union involving long bones. 254 patients were excluded based on factors such as multifocal osteomyelitis, joint involvement etc., hence a total of 99 patients enrolled in this study.

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SETTING

The study was conducted in Christian Medical College, Vellore which is a leading tertiary care centre in the country. The study period was from 01.01.2017- 31.06.2019.

A list of all patients with chronic osteomyelitis was obtained from the IP and OP registry of the Department of Orthopaedics Unit I, II and III. All patients who had undergone surgical debridement were identified and those fulfilling the inclusion criteria were recruited. All patients who suffered from a clinically or radiologically diagnosed or culture proven chronic osteomyelitis were included in the study

irrespective of the number of past surgeries performed in the same or other medical centres.

The inclusion and exclusion criteria for patient selection is as follows: -

The inclusion and exclusion criteria for patient selection that was adhered to in this study is mentioned below: -

INCLUSION CRITERIA

 Age : above 18 years

 Single Long bone osteomyelitis

 Infected non-union

 Patients who have undergone surgical debridement in CMCH, Department of Orthopaedics.

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 Chronic Osteomyelitis ; Host Type A and B –( Cierny and Mader classification)

EXCLUSION CRITERIA

 Multifocal osteomyelitis

 Patients with vascular compromise

 Type C Host

 Joint involvement

 Bone loss -(bone transport/lengthening)

All the patients were contacted except few patients from other nationalities. The patients were invited for follow up and were examined and their functional outcome was assessed using the Association for the Study and Application of Methods of Illizarov (ASAMI),Musculoskeletal Tumour Society (MSTS-Functional category) and Lower Extremity Functional Scale (LEFS) for lower limb long bone osteomyelitis and Disability of the Arm, Shoulder and Hand (DASH) questionnaire was used for upper limb long bone osteomyelitis.

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The patients were who had been planned for surgery had been explained in detail regarding the study and were consented.

VARIABLES EXPOSURE:

Patients who have undergone surgical debridement.

DIAGNOSTIC CRITERIA:

Relapse of chronic osteomyelitis was defined as infection occurring again at the same site from where it had been considered to be cleared previously and which was treated specifically with surgery. The description of infection includes;-

 the growth of same pathogen or different pathogen in the repeat cultures done on presentation

Or,

 Culture positive or culture negative patients(aseptic inflammation), presenting with

- Discharging sinus Or,

 Patients presenting with pain, tenderness or with elevated or abnormal levels of systemic markers of inflammation.

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A patient during follow-up was considered relapse-free, if there were no clinical signs of infection such as warmth, discharging sinus, fever, swelling or tenderness. Also the laboratory values (ESR and CRP) should have normalized for confirmation.(24)

SAMPLE SIZE CALCULATION

This was observational cohort study and patients were selected on presentation and during follow-up. There was no numerical limitation for patient recruitment.

However, for statistical and completion purposes, as per the IRB requirements we incorporated a baseline sample size of 150 patients.

Proportion of disease among unexposed ( Non-MRI Group relapse) 30%

Relative Risk 0.50

Proportion of disease among exposed (MRI Group relapse ) 15%

Power (1- beta) % 80

Alpha error (%) 10

1 or 2 sided 1

Required sample size in each group (equal allocation method) 69 We have chosen 75 in each arm (last column-including 6 for loss to follow up) +6 Note: We used 1 sided alfa as we are sure of lower relapse with MRI. 75+75 = 150

TOTAL

Table. 3. Details of sample size calculation.

The anticipated sample size was 150 patients, but the number of patients who could be followed up and recruited in the given duration was 99.

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METHODOLOGY

The protocol of this study was submitted for Institutional review board

(IRB) clearance before commencing the study and approval was obtained – IRB Minute Number 10941 dated 07.11.2017. Using the clinical work station (version 5.73.20, product of the department of computerised hospital information

Processing services (CHIPS), Christian Medical College, Vellore, Tamil Nadu, India) and the electronic medical records, the details of the patients who

Underwent surgical treatment for chronic osteomyelitis were collected.

All patients underwent blood investigations and radiographs following a detailed clinical examination at the time of follow-up. In certain instances patients were explained prior to index surgery regarding the need for staged procedures and were advised to review at the regular intervals for follow-op. The focus of data collection was to report the frequency of relapse at different stages of follow-up and also to assess the functional outcome of patients following surgery.

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Figure 5. Diagrammatic algorithm for patient recruitment and selection.

1 • Culture/Bone biopsy/radiologically or clinically proven cases of chronic osteomyelitis, who have undergone surgical debridement.

2 • Fulfillment of the Inclusion criteria

3 • Patient recruitment with informed consent

4 • Prospective analysis

• Relapse vs Non-relapse (minimum of 3 months maximum of 1 year followup)

• MRI vs Non-MRI group

5 • 3 months, 6 months, 1 year and 1 1/2 years from the time of surgical debridement

6 • Functional outcome assessment by direct standard questionnaire method - by

prospective follow-up.

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Patients participating

in the study n=99

Total no.of patients identified n=353

Infected non-union (n=34)

Chronic osteomyelitis

(n=65)

Figure. 6 Flowchart showing the total number of patients and categorization.

The purpose of the study and its details were explained and all queries were clarified.

An informed consent was obtained and the patients were examined and their respective data was entered in the proforma attached.

If the participants in the study were unable to travel to the study centre, blood results and radiological investigations performed at a hospital in their hometown was

obtained through electronic mail and the functional outcome was obtained over the phone.

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The patients were divided into cohorts based on variables such as pre-operative MRI, specific diagnosis i.e., infected non-union/chronic osteomyelitis etc.

For each patient selected for the study, a proforma (Annexure 1) was filled. Data collected from these patients and their records were subjected to statistical analysis with the help and guidance of a biostatistician.

STATISTICAL METHODS

The entire data was entered using EPIDATA (v. 3.1) software and screened for outliers and extreme values using Box-Cox plot and histogram (for shape of the distribution). Summary of statistics was provided for reporting demographic and clinical characteristics. ANOVA was used to analyse continuous variable with pre-op frequency measures and Chi-square performed for categorical variables with

functional outcome. Differences where considered significant at p<0.05. All the statistical analysis was performed using SPSS 18.0.

This study was accepted by the Institutional Review Board, Christian Medical College,Vellore.

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BASELINE CHARACTERISTICS:

During the study period a total of 99 patients were recruited for our study out of which 65 had chronic osteomyelitis and 34 infected non-union. The median age of the

patients was 33 years; 81.8 % being males. With regards to the etiology of bone infection 80.8% belonged to the post-traumatic osteomyelitis group and only 19.2% to the haematogenous group. 95 patients had involvement of the long bones of the lower limb (Femur and tibia), and in the remaining 4 patients, the

humerus was involved. The inclusion criteria were patients above 18 years of age with a minimum of 3 months follow-up.

All patients with suspected chronic osteomyelitis/infected non-union underwent preliminary blood investigations and radiographs following a detailed clinical examination. The patients were informed regarding the prognosis and after prior discussion with a senior orthopedic surgeon, the decision regarding surgical debridement was made. The mode of stabilization was chosen intraoperatively depending on the extent of involvement, severity of infection and the soft tissue condition. In certain instances patients were explained prior to surgery regarding the need for staged procedures and were advised to review at the regular intervals. The focus of data collection was to make comparisons among patients according to outcome (treatment success or failure) at different stages of follow-up and to assess the functional outcome of patients following surgery.

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AGE DISTRIBUTION OF THE STUDY PARTICIPANTS

81.80%

18.20%

GENDER DISTRIBUTION

Males Female

Figure 8. Box plot showing the age distribution of the participants (mean=34.82, median=33years)

Figure 7. Gender distribution of participants

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ETIOLOGICAL DISTRIBUTION

The majority of patients diagnosed with bone infection (chronic osteomyelitis) were due to post-traumatic cause (n=80, 80.8%) and the remaining due to haematogenous aetiology (n=19, 19.2%).

80

19

0 10 20 30 40 50 60 70 80 90

Post-traumatic Hematogenous

Figure 9. Etiological distribution of participants

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Most of the patients who had participated in the study belonged to Semi-skilled group.

5 4

43 18 15

12 2

Unemployed Unskilled Semi-skilled Skilled Clerk/Shopkeeper Semi-professional Professional

59

37

4

Femur Tibia Humerus

BONE INVOLVEMENT

Figure 10. Occupation wise distribution(according to Modified Kuppusamy scale).

Figure 11. Frequency of distribution among longbone infections

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The chart showing frequency of distribution among long bone osteomyelitis and infected non-unions combined; number of patients with bone infection involving the femur was 59 and that of the tibia was 37.

The number of patients with associated co-morbid illness was about 21, out of which 12 had diabetes and 9 patients were hypertensives. The preoperative usage of walking aid was also studied and 33.3% of the patients were found to be using walking aid of any form i.e., crutch or walking stick before the index surgery. (As shown in fig.10 below).

YES 33%

NO 62%

Figure 12. Percentage of participants using walking aid pre-operatively

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Out of 99 patient in our study population 63 patients had presence of sequestrum according to pre-operative radiographs obtained and it was confirmed by an

orthopedic resident, hence to eliminate inter-observer bias. The choice of secondary radiographic investigations was done according the discretion of the senior orthopedic surgeon after prior discussion. The number of patients who had a pre-operative MRI was 25 (fig.14).

63

36

0 10 20 30 40 50 60 70

Present Absent

NO>OF PATIENTS

SEQUESTRUM

Fig. 13 THE NO.OF CASES WITH OR WITHOUT SEQUESTRUM .

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The percentage of patients with MRI done pre-operatively was 25% (n=24).Most of the patients with Infected non-unions did not have a pre-operative MRI. The choice of pre-operative MRI was dependent of the discretion of the treating orthopaedic surgeon.

YES 25%

NO 75%

YES NO

Fig. 14. Pre-operative Magnetic Resonance Imaging

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PRE-OPERATIVE SCORES

Lower Extremity Functional Scale (LEFS)

The above figure shows the Lower extremity functional scale (LEFS) distribution for our study population. LEFS was one the scores used to assess functional outcome of the patients in our study population. This self-reported questionnaire includes a set of 20 questions which focus on functional leg activities each scored on a 5-point ordinal scale ranging from 0(extremely difficult/impossible to perform) to 4(no difficulty).It is scored out a maximum of 80 and a minimal detectable change of 9 points was

considered clinically significant, the functional ability was to expressed nominally.

The sensitivity to clinical change, reliability and the construct validity of the LEFS has

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been shown to be superior to other lower limb functional outcome scales especially in prospective studies.(25)

In our study population the Mean – preoperative LEFS was 44 and the median was 42, (Standard deviation = 13.391, skewed data). The minimum score was 18 and the

maximum was 74.

Association for the Study and Application of the Methods of Illizarov (ASAMI)

The ASAMI criteria has two components, the bone score which is assessed radiologically and a functional score which is assessed by history and clinical examination. In this study, the ASAMI-Functional score was used.

POOR 10%

FAIR 63%

GOOD 24%

EXCELLENT 3%

POOR FAIR GOOD EXCELLENT

Fig 16. PRE-OP ASAMI (FUNCTIONAL OUTCOME) DISTRIBUTION

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The above pie-chart (fig.16) shows the category of ASAMI (functional) score for a total of 95 patients (as 4 patients were diagnosed with humerus osteomyelitis), pre- operatively. ASAMI – FUNCTIONAL SCORE consists of four categories, involving specific clinical findings which are to be fulfilled for a patient to be classified

accordingly.

ASAMI –FUNCTIONAL

Excellent: Active, no limp, minimum stiffness (loss of < 15° knee extension / <15°

dorsiflexion of ankles), no reflex sympathetic dystrophy, insignificant pain.

Good: Active, with one or two of the following: Limp, stiffness, RSD, significant pain Fair: Active, with three or all of the following: Limp, stiffness, RSD, significant pain Poor: Inactive (unemployment or inability to daily activities of injury), Amputation.

MSTS – EMOTIONAL STATUS

The emotional acceptance level at the time of presentation was assessed after explaining in detail regarding the condition and the complete management of the disease involved, including the chance of recurrence, staged surgeries, costs involved, multiple hospital visits, regular follow-up etc.

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As shown in the figure17, 62% (59) of the patient disliked their condition at the time of presentation and 38% (36) patients accepted the condition at presentation. This serves as vital information for understanding the patient compliance for treatment. The MSTS-Emotional component consists of four categories related to emotional status.

These include;-

 Enthusiastic

 Satisfied

 Accepts

 Dislikes

DISLIKES: 59, 62%

ACCEPTS : 36, 38%

SATISFIED 0, 0%

ENTHUSIASTIC 0, 0%

Fig.17. Pre-operative Emotional acceptance distribution at the time of presentation (based on MSTS)

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There was predominance of Cierny-made type IV patients in our study population (42%, n=41) and 83 patients, i.e. about 84% of the patients belonged to Cierny-mader Host A type.

22, 22%

9, 9%

27, 27%

41, 42%

CIERNY-MADER(ANATOMICAL) DISTRIBUTION

TYPE-I : MEDULLARY TYPE-II : SUPERFICIAL TYPE-III: LOCALIZED TYPE-IV: DIFFUSE

Fig.18 Frequency of distribution based on Cierny-mader classification (anatomical).

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As shown above (Fig.19), most participants (n=83, 83.8%) belonged to the Host category A and 16(16.16%) belonged to Host category B.

Fig. 20 Pre-op Function in Chronic osteomyelitis vs Infected Non-unions HOST B , 16

HOST A ; 83

0 10 20 30 40 50 60 70 80 90

HOST A HOST B

0

22(36.06%)

37(60.7%)

2 2

(50%) 15(44.11%)

0

0 5 10 15 20 25 30 35 40

TOTAL DISABILITY PARTIAL DISABILITY RECREATIONAL RESTRICTION

NO RESTRICTION

NO.OF PATIENTS

PRE-OP MSTS-FUNCTIONAL CATEGORY

CHRONIC OSTEOMYELITIS INFECTED NON-UNION Fig.19 Frequency of distribution based on Cierny-mader classification Physiological Host types

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The above graph represents the number of patients in each of the diagnostic groups (Chronic osteomyelitis vs Infected non-unions) categorized according to the MSTS- Functional criteria, during the pre-operative period.

INTRAOPERATIVE CONSIDERATIONS

The intra-operative details were collected from the IP registry.

Broadly there were four queries to be answered, to evaluate intra-op bone condition and debridement:

- Was there presence of pus intra-op?

- Was the sinus excised (among inviduals who presented with a discharging sinus)?

- Was there significant sclerotic bone encountered?

- Had a cortical window been made (to decompress any collection)?

- Was the sequestrum removed?

PUS PRESENT INTRAOP PUS ABSENT INTRAOP

38 (38.4%)

61 (61.6%)

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 38.4 % of the patients had been found to have pus present site of bone infection.

 In 52 out of 99 patients a cortical window was made – as a part of the surgical procedure.

This suggests that the extent of bone involvement (according to the Cierny-mader classification), condition of the bone and the presence of intra-osseous abscess plays an important role in the appropriate surgical steps undertaken during surgical

debridement.

38%

62%

PRESENT ABSENT

CORTICAL WINDOW MADE CORTICAL WINDOW NOT MADE

52 patients 47 patients

Fig. 21 Proportion of cases where Pus/Purulent material was visualised intra-op.

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SURGICAL TECHNIQUES

The primary surgical debridement was also accompanied by other additional

procedures for elimination of infection and stabilization. The total number of patients who had undergone a surgical debridement with or without implant removal were 63.

In 15.15% (n=15) patient’s cement spacer or antibiotics beads was used for local antibiotic release and for filling bone defects following the resection of devitalized bone. In 15.15% (n-=15) patients additional implants were used (predominantly the infected non-union group), out of which 2 patients due to failure of treatment were revised to Illizarov ring fixation after 1 year from the index surgery. 1 patient with infected non-union had to undergo an amputation.

Soft tissue coverage was required for 5 patients following the primary surgical debridement.

Patients were monitored post-operatively and the appropriate antibiotics were administered Infectious diseases physicians were involved whenever required. The patient profile as well other factors such as compliance and efficacy where also considered during the choice of antimicrobial treatment. During the immediate post- op period, regular dressings were done and wound healing was monitored and 8 patients required re-debridement and washout during the same admission.

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FOLLOW-UP DETAILS

The anticipated patient follow-up was at 3, 6 and 12 months post-operatively. In our study, a total of 45 patients had been followed up at 1 year, either clinically or via telephone. Among these, 21 patients had chronic osteomyelitis and the remaining 24 had infected non-union. The number of patients who had followed up (clinically assessed by the surgeon) at one year was 31, while the remaining 14 patients were assessed using the LEFS telephonically. Among this subset of patients, the clinical scores such as asami-functional or the msts-functional score could not be applied.

Hence LEFS, being more reliable and with better construct validity, was used to assess the functional outcome in the patients who had not had clinical follow-up at 1 year post-surgery. 17 out of 29 patients with infected non-union had been clinically followed-up at 1 year, and 4 patients had fracture union radiologically. 5 patients had not completed treatment and it was less than 1 year from their index surgery. All clinically followed-up patients had radiographs done but ESR and CRP were not done on a regular basis.

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---

RESULTS

---

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POST-OPERATIVE FINDINGS

CULTURE POSITIVITY

Out of 99 patients in the study population, 77(78%) patients were culture positive and 20(20%) were culture negative and in 2 patients intra-op cultures were not done.

Culture pos(n=77)

78%

Culture neg(n=20)

20%

Not done(n=2) 2%

Culture pos(n=77) Culture neg(n=20) Not done(n=2)

Fig. 22 Frequency of distribution based on culture reports