|Year : 2014 | Volume
| Issue : 1 | Page : 67-69
Case of chronic patellar osteomyelitis
Chawa Shamsunder, Shaik Ajaz, Vakati Raghavendra Sujitkumar
Department of Orthopedics, Deccan College of Medical Sciences, Hyderabad, Andhra Pradesh, India
|Date of Web Publication||15-Mar-2014|
Department of Orthopedics, Deccan College of Medical Sciences, Hyderabad, Andhra Pradesh
Source of Support: None, Conflict of Interest: None
Chronic osteomyelitis of patella, a rare clinical entity has been reported mostly in 5-15 years of age group, but is rare in adults. Literature search yields only few cases reported worldwide. We report a case of chronic osteomyelitis of right patella in a 16 year old male with a previous history of trauma. He presented with pus discharging from the right knee with limitation of joint movement. Radiographs showed lytic lesions of complete patella which was confirmed on computed tomography. Since the lesion was grossly spread over the complete patella, patellectomy was done. Our case suggests that chronic osteomyelitis is more likely to be caused by post-traumatic open injury to knee.
Keywords: Lytic lesions, osteomyelitis, patella, patellectomy
|How to cite this article:|
Shamsunder C, Ajaz S, Sujitkumar VR. Case of chronic patellar osteomyelitis. Muller J Med Sci Res 2014;5:67-9
| Introduction|| |
Chronic osteomyelitis of patella is a rare clinical entity. In post-traumatic or exogenous osteomyelitis, the infection is always associated with trauma, whether it be of unplanned (i.e., a motor vehicle accident) or the planned (i.e., a surgical procedure) variety. Staphylococcus aureus is the most common isolate in all types of bone infection and is implicated in 50-75% cases of chronic osteomyelitis. , Even Staphylococcus epidermidis other Gram-negative bacilli each are involved in approximately one-third cases of chronic osteomyelitis.  Gram-negative rods have been implicated in 50% of chronic osteomyelitis cases.  Bodur et al. have reported a case of arthritis and patellar osteomyelitis caused by Aspergillus fumigates. 
Diagnosis of this condition is not made in many patients, sometimes diagnosed once the suppuration appears.  Radiographs and computed tomography will be of value in arriving at a diagnosis and histopathology will be confirmatory.
We describe a case of chronic osteomyelitis of patella of a young male patient and its management.
| Case Report|| |
This was a case report of a 16-year-old young male patient presented to our hospital with pus discharging from his right knee and limitation of movements. He was able to flex only 45° from extended knee position [Figure 1]. On examination, swelling and tenderness over the right knee was noted. He had a history of injury to his right knee (road traffic accident) 8 years ago where he lost skin over the right knee and complete abrasions and laceration to his right mid-thigh to knee, for which skin grafting was done. X-ray of the knee joint showed osteomyelitis of patella [Figure 2]. Computed tomography scan of the right patella revealed characteristic features of chronic osteomyelitis such as abnormal thickening of the affected cortical bone, with sclerotic changes, encroachment of the medullary cavity and chronic draining sinus [Figure 3]. Culture of the pus from the wound showed the growth of S. aureus.
|Figure 1: Limitation of extension of the knee allowing maximum flexion of only 45° from extended knee position, clinically|
Click here to view
|Figure 2: Pre-operative X-ray of right knee joint showing features of chronic osteomyelitis|
Click here to view
Right patellectomy was performed under general anesthesia [Figure 4] and [Figure 5]. There was no problem encountered during the reconstruction of patellar ligament and in the soft-tissue coverage over the repair. The infective focus was not there after the surgery. [Figure 6] shows the cut section of patella and [Figure 7] shows post-operative radiograph of right patella. Histopathology findings confirmed the diagnosis of chronic osteomyelitis of right patella. Patient was advised immobilization 6 weeks of pre- and post-surgery. Antibiotic injection TAZAR 4.5 g (piperacillin + tazobactum) was administered 3 days pre-operatively and 6 weeks post-surgery.
Patient was followed-up for 1 year. Patient benefited from the surgery in terms of improvement in the range of movement resulting in patient carrying out his routine activities which was limited prior to surgery [Figure 8].
|Figure 8: Post follow-up showing improved flexion at right knee indicating near normal range of activities|
Click here to view
| Discussion|| |
Isolated lesions of the patella are unusual. The list of pathological entities include trauma, degenerative diseases, primary or metastatic tumors, congenital defects and cysts and infections. Acute pyogenic hematogenous osteomyelitis of the patella is exceedingly rare in adults and in children under the age of 5 years which could be due to its cartilaginous nature and little blood supply to patella. Vascularization proceeds with ossification reaching a maximum at 12 years and at 15 years the patella is ossified completely. After ossification the vascularity decreases. The incidence of hematogenous osteomyelitis of the patella is believed to correspond directly to the increased vascularity of the patella which is maximum between 5 and 15 years of age and hence it occurs commonly in this age group. ,, This could also account for it being rare in adults where the vascularity is reduced. In adults a history of trauma is usually present in most of the cases. It is also often believed to be the sequel of a prepatellar bursitis.  S aureusis perhaps the most common organism responsible for causing acute osteomyelitis of the patella.  Tuberculous osteomyelitis of patella  is also an entity of which one should be aware, but it often tends to be multifocal. S. aureus have been isolated from the tissues of patellar osteomyelitis ,, and it was found in our case also.
Diagnosis at early stages of the disease will either avoid or postpone surgical intervention. Curetting the affected part, without opening is considered in uncomplicated cases and in more advanced cases, radical arthrotomy with total extirpation of patella is advocated.  Malignant transformation can occur and Patel et al. have reported a case of squamous cell carcinoma arising from chronic osteomyelitis of patella. 
In our case, trauma was the predisposing cause for patellar osteomyelitis. Diagnosis was confirmed radiologically and histologically. Patella was the primary focus and we ruled out all other source of infection. We performed patellectomy, which is the standard management advocated. Antibiotics and other symptomatic management were given along with rehabilitation measures including physiotherapy. Intra- and post-operative period, follow-up period was uneventful, without any complications. There was a significant improvement in the joint movements post-surgery.
| Acknowledgment|| |
We acknowledge the patient who agreed to publish this data. We appreciate the support of Dr. M. S. Latha who helped us in the preparation, editing of this manuscript.
| References|| |
|1.||Cierny G III. Classiﬁcation and treatment of adult osteomyelitis. In: Evarts CM, editor. Surgery of the Musculoskeletal System. 2 nd ed. London: Churchill Livingstone; 1990. p. 4337. |
|2.||Clawson DK, Dunn AW. Management of common bacterial infections of bones and joints. J Bone Joint Surg Am 1967;49:164-82. |
|3.||Bergman BR. Antibiotic prophylaxis in open and closed fractures: A controlled clinical trial. Acta Orthop Scand 1982;53:57-62. |
|4.||Patzakis MJ, Harvey JP Jr, Ivler D. The role of antibiotics in the management of open fractures. J Bone Joint Surg Am 1974;56:532-41. |
|5.||Bodur H, Ozoran K, Colpan A, Balaban N, Tabak Y, Kulacoglu S. Arthritis and osteomyelitis due to Aspergillus fumigatus: A 17 years old boy with chronic granulomatous disease. Ann Clin Microbiol Antimicrob 2003;2:2. |
|6.||Christopher F. Acute osteomyelitis of the patella. J Bone Joint Surg Case Connector 1933;15:1012-4. |
|7.||Richter R, Herceg K, Köhler G. The patellar focus, a rare form of localization of bone tuberculosis. Z Orthop Ihre Grenzgeb 1982;120:5-9. |
|8.||Evans DK. Osteomyelitis of patella. J Bone Joint Surg 1962;44:319-23. |
|9.||Patel NM, Weiner SD, Senior M. Squamous cell carcinoma arising from chronic osteomyelitis of the patella. Orthopedics 2002;25:334-6. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5], [Figure 6], [Figure 7], [Figure 8]