N Ferreira

Prevention and management of external fixator pin track sepsis

Pin track-associated complications are almost universal findings with the use of external fixation. These complications are catastrophic if it leads to the failure of the bone–pin interface and could lead to pin loosening, fracture non-union and chronic osteomyelitis. Strategies proposed for the prevention and management of pin track complications are diverse and constantly changing. Prevention of external fixation pin track infection is a complex and ongoing task that requires attention to detail, meticulous surgical technique and constant vigilance.

Osteosarcoma presentation stages at a tumour unit in South Africa

BACKGROUND Osteosarcoma is the most common malignant bone tumour found in children and adolescents. Changed treatment protocols have resulted in improved survival and the opportunity for limb salvage surgery. Despite these advances, the outcome is mainly determined by the stage of disease at presentation, making early referral to a tumour unit essential. METHODS Between July 2009 and October 2011, 25 consecutive patients were diagnosed with biopsy-confirmed osteosarcoma. Their records were reviewed and information extracted regarding clinical presentation, histological subtype and stage of disease. RESULTS Twenty-four patients met the inclusion and exclusion criteria. Conventional osteosarcoma was the most common histological diagnosis encountered; 16 out of 24 (66.7%) patients had metastases at presentation; 6 of the remaining had advanced local disease with very large tumours or pathological fractures that precluded limb salvage surgery. CONCLUSION The great majority of patients referred to our tumour unit present with locally advanced or metastatic disease, which limits treatment options and adversely affects survival. Increased awareness, a high index of suspicion and appropriate early referral is crucial to enable limb salvage surgery and increase disease-free survival rates.

Pre-treatment serum lactate dehydrogenase and alkaline phosphatase as predictors of metastases in extremity osteosarcoma

Background The prognosis of patients with metastatic osteosarcoma remains poor. However, the chance of survival can be improved by surgical resection of all metastases. In this study we investigate the value of serum alkaline phosphatase (ALP) and lactate dehydrogenase (LDH) in predicting the presence of metastatic disease at time of diagnosis. Methods Sixty-one patients with histologically confirmed conventional osteosarcoma of the extremity were included in the study. Only 19.7% of cases presented without evidence of systemic spread of the disease. Pre-treatment serum ALP and LDH were analysed in patients with and without skeletal or pulmonary metastases. Results Serum LDH and ALP levels were not significantly different in patients with or without pulmonary metastases (p=0.88 and p=0.47, respectively). The serum LDH and ALP levels did however differ significantly in patients with or without skeletal metastases (p<0.001 and p=0.02, respectively). The optimal breakpoint for serum LDH as a marker of skeletal metastases was 849 IU/L (AUC 0.839; Sensitivity=0.88; Specificity=0.73). LDH >454 IU/L equated to 100% sensitivity for detected bone metastases (positive diagnostic likelihood ratio (DLR)=1.32). With a cut-off of 76 IU/L a sensitivity of 100% was reached for serum ALP predicting the presence of skeletal metastases (positive DLR=1.1). In a multivariate analysis both LDH ≥850 IU/L (odds ratio [OR]=9; 95% confidence interval (CI) 1.8–44.3) and ALP ≥280 IU/L (OR=10.3; 95% CI 2.1–50.5) were predictive of skeletal metastases. LDH however lost its significance in a multivariate model which included pre-treatment tumour volume. Conclusion In cases of osteosarcoma with LDH >850 IU/L and/or ALP >280 IU/L it may be prudent to consider more sensitive staging investigations for detection of skeletal metastases. Further research is required to determine the value and the most sensitive cut-off points of serum ALP and LDH in the prediction of skeletal metastases.

Radiographic analysis of hexapod external fixators: fundamental differences between the Taylor Spatial Frame and TrueLok-Hex.

Abstract Hexapod circular external fixators are extremely accurate at correcting deformities in three dimensions. In order to exploit this accuracy, however, the surgeon must be able to accurately analyse the deformity and mounting parameters on post-operative radiographs. A Sawbone® model was created to simulate a mid-shaft tibial fracture with deformity. A 180 mm ring was applied oblique to the proximal segment of the Sawbone® model, in both the sagittal and coronal planes. Standard radiographs were taken of the model and analysed using the described Taylor Spatial Frame and TrueLok-Hex methods. The TrueLok-Hex software allows the surgeon the ability to program reference rings that are not orthogonally mounted. Apart from this software difference, the described analysis methods resulted in variation in all translational measurements for both deformity and mounting parameters. In conclusion, the radiographic analysis of the Taylor Spatial Frame and TrueLok-Hex are fundamentally different. These differences must be appreciated in order to use these systems effectively.

Bicondylar tibial plateau fractures treated with fine-wire circular external fixation

Bicondylar tibial plateau fractures are serious injuries to a major weight-bearing joint. These injuries are often associated with severe soft tissue injuries that complicate surgical management. We reviewed 54 consecutive patients who sustained bicondylar tibial plateau fractures that were treated with limited open reduction and cannulated screw fixation combined with fine-wire circular external fixation. Forty-six patients met the inclusion criteria of this retrospective review. Eight patients were excluded because they did not complete a minimum of 1-year follow-up. Thirty-six patients had Schatzker type-VI, and ten patients had Schatzker type-V fractures. All fractures were united without loss of reduction; there were no incidences of wound complications, osteomyelitis or septic arthritis. The average Knee Society Clinical Rating Score was 81.6, translating to good clinical results. Minor pin track infection was the most common complication encountered. This review concludes that fine-wire circular external fixation, combined with limited open reduction and cannulated screw fixation, consistently produces good functional results without serious complications.

Isolated cryptococcal osteomyelitis in an immune-competent host: a case report

Cryptococcus neoformans is a ubiquitous organism that often causes opportunistic infections in immune-compromised patients. The pulmonary and central nervous systems are most commonly affected. Osseous involvement is infrequent and is usually associated with disseminated systemic infection. Isolated cryptococcal osteomyelitis is exceedingly rare. We report the case of a 56-year-old immunocompetent man who presented with isolated cryptococcal osteomyelitis of the humerus.

Management of tibial non-unions according to a novel treatment algorithm

Tibial non-unions represent a spectrum of conditions that are challenging to treat. The optimal management remains unclear despite the frequency with which these diagnoses are encountered. The aim of this study was to determine the outcome of tibial non-unions managed according to a novel tibial non-union treatment algorithm. One hundred and eighteen consecutive patients with 122 uninfected tibial non-unions were treated according to our proposed tibial non-union treatment algorithm. All patients were followed-up clinically and radiologically for a minimum of six months after external fixator removal. Four patients were excluded because they did not complete the intended treatment process. The final study population consisted of 94 men and 24 women with a mean age of 34 years. Sixty-seven non-unions were stiff hypertrophic, 32 mobile atrophic, 16 mobile oligotrophic and one true pseudoarthrosis. Six non-unions were classified as type B1 defect non-unions. Bony union was achieved after the initial surgery in 113/122 (92.6%) tibias. Nine patients had failure of treatment. Seven persistent non-unions were successfully retreated according to the tibial non-union treatment algorithm. This resulted in final bony union in 120/122 (98.3%) tibias. The proposed tibial non-union treatment algorithm appears to produce high union rates across a diverse group of tibial non-unions. Tibial non-unions however, remain difficult to treat and should be referred to specialist units where advanced reconstructive techniques are practiced on a regular basis.

Hexapod external fixator closed distraction in the management of stiff hypertrophic tibial nonunions

Tibial nonunion represents a spectrum of conditions which are challenging to treat, and optimal management remains unclear despite its high rate of incidence. We present 44 consecutive patients with 46 stiff tibial nonunions, treated with hexapod external fixators and distraction to achieve union and gradual deformity correction. There were 31 men and 13 women with a mean age of 35 years (18 to 68) and a mean follow-up of 12 months (6 to 40). No tibial osteotomies or bone graft procedures were performed. Bony union was achieved after the initial surgery in 41 (89.1%) tibias. Four persistent nonunions united after repeat treatment with closed hexapod distraction, resulting in bony union in 45 (97.8%) patients. The mean time to union was 23 weeks (11 to 49). Leg-length was restored to within 1 cm of the contralateral side in all tibias. Mechanical alignment was restored to within 5° of normal in 42 (91.3%) tibias. Closed distraction of stiff tibial nonunions can predictably lead to union without further surgery or bone graft. In addition to generating the required distraction to achieve union, hexapod circular external fixators can accurately correct concurrent deformities and limb-length discrepancies.

Mechanobiology in the management of mobile atrophic and oligotrophic tibial nonunions

BACKGROUND Recent research indicates that atrophic nonunions are biologically active and may heal in the optimal biomechanical environment. METHODS Thirty-three patients with mobile atrophic and oligotrophic tibial nonunions were treated with circular external fixation and functional rehabilitation. Seven patients required autogenous bone graft procedures. RESULTS Bony union was achieved after the initial surgery in 31/33 (93.9%) tibias. Two persistent nonunions were successfully treated with repeat circular external fixation without bone graft. This resulted in final bony union in 33/33 (100%) patients. CONCLUSION Mechanobiological stimulation of tibial nonunions can produce union even if the biological activity appears to be low.

Osteosarcoma in Adult Patients Living with HIV/AIDS

Background. HIV infection has reached epidemic proportions in South Africa, with an estimated prevalence of 21.5% in adults living in the province of KwaZulu-Natal. Several malignancies have been identified as part of the spectrum of immunosuppression-related manifestations of HIV infection. Very few reports, however, exist regarding the occurrence of non-AIDS-defining sarcomas in the extremities or limb girdles. Methods. A retrospective review was performed on all adult patients, between the ages of 30 and 60 years, with histologically confirmed osteosarcomas of the appendicular skeleton referred to a tertiary-level orthopaedic oncology unit. Results. Five out of the nine patients (62.5%) included in the study were found to be HIV positive. The average CD4 count of these patients was 278 (237–301) cells/mm3, indicating advanced immunological compromise. Three of the malignancies in HIV-positive patients occurred in preexisting benign or low-grade tumours. Conclusion. A heightened index of suspicion is required in HIV patients presenting with unexplained bone and joint pain or swelling. Judicious use of appropriate radiological investigation, including magnetic resonance imaging of suspicious lesions and timely referral to an appropriate specialized orthopaedic oncology unit, is recommended.