Faculty Bibliography

Frontal plane malalignment of the lower extremity results in abnormal load distribution across the knee joint. Consequences of this increased stress may lead to compartmental osteoarthritis. High tibial osteotomy is well established for early osteoarthritis of the knee joint in middle-aged patients. We hypothesize that earlier realignment of the varus knee can be performed without undue risks and debilitation toward the young active patient and with good results in short-term follow-up. Open-wedge high tibia osteotomy using the Puddu plate was performed on eleven patients (19 knees) under 25 years of age for constitutional high tibia vara. The mechanical femorotibial angle (FTA) and Knee Society Knee Score (KSKS) were compared pre-operatively and 24 months post-operatively. The average FTA improved from +8.8 degrees (+5 - +16) to -0.1 (-2 - +5). The average KSKS improved from 74 (50-100) to 93 (60-100) and the function score improved from 84 (50-100) to 95 (60-100). Special concerns in this age group include unsightly cosmesis, and kneeling pain and discomfort. Open-wedge high tibia osteotomy provides a satisfactory solution for constitutional high tibia vara with minor morbidity on behalf of the patient in the short-term follow-up period.

Structural defects of the posterior arch of the atlas are rare, and range from clefts of variable location and size to more extensive defects such as complete agenesis. These abnormalities are usually incidental radiological findings. We present a case of a fracture of the anterior arch of the atlas associated with a congenital abnormality of the posterior arch.

We investigated the role of zoledronic acid on the regenerate and native bone after consolidation and removal of the external fixator in a rabbit model of distraction osteogenesis using 28 New Zealand white rabbits. The rabbits were randomly distributed into two groups. The first group received three doses of zoledronic acid (ZA) 0.1 mg/kg subcutaneously at weekly intervals while the second group received injections of sterile saline. Distraction started on day 7 at a rate of 0.8 mm/day for 12 days. At week 3 the average lengthening, regenerate density, and regenerate continuity were comparable between the two groups. At week 11 the regenerate in the treated group had a significant increase in Bone Mineral Density (BMD) and Bone Mineral Content (BMC) compared to the placebo group. On axial compression, the regenerate showed an increase in the peak load and a higher modulus of elasticity in the treated group. At 6 months, radiographs demonstrated signs of osteopenia of the proximal metaphysis in the control group, and failure of new bone formation around the pin sites in the treated group. BMC and BMD value differences between the two groups were not statistically significant. Histologically, there was persistence of more bone trabeculae in the medullary canal of the regenerate with the persistence of the pin-holes in the treated group. Mechanically, the regenerates in the treated group remain stronger in resisting the axial compression. The proximal fragment in the treated group exhibited a statistically significant decrease in the peak load, toughness and efail %. In conclusion, bisphosphonate-treated rabbits have a stronger regenerate during distraction, and directly after removal of the fixator. They do not develop disuse osteopenia in their lengthened tibia. This treatment may shorten the time in the external fixator and prevent fragility fractures in the treated extremity. However, its long-term safety has not yet been established.

Novel biomechanical methods have been developed to objectively measure acute fracture severity (from inter-fragmentary surface area) and chronic contact stress challenge (from patient-specific finite element analysis) in articular fractures. These new methods help clarify the pathomechanics of the development of post-traumatic osteoarthritis, and can contribute directly to the clinical care of patients. In this manuscript, the value of these two new measures is demonstrated in three illustrative tibial plafond fracture cases, in which both metrics are correlated with cartilage status and with patient outcomes at a minimum of two years after injury. These clinical cases demonstrate the utility of new biomechanical variables to advance clinical research and patient care, by providing a basis to predict outcome and select treatment.

INTRODUCTION/BACKGROUND:We evaluated the local recurrence rate (LRR) of bone sarcoma along the core-needle biopsy (CNB) tract in patients who underwent limb Salvage Surgery (LSS) following a diagnostic CNB performed irrespective of the planned surgical incision site and for which surgery did not involve any biopsy tract removal. METHODS:A retrospective review of 10 pediatric patients diagnosed with bone sarcoma using a computed tomography-guided core-needle biopsy, with evaluation of medical records, pathological specimens and radiological films from the date of diagnosis until the most recent follow-up. RESULTS:None of the patients experienced local recurrence during their follow up, despite the lack of biopsy site resection. CT scans of the involved extremities were negative for any suspicious lesions in all patients up until the most recent follow-up. CONCLUSIONS:Our study and review of the literature suggest that the incidence of tumor seeding the CNB tract in bone sarcoma patients is apparently low, and possibly negligible. CNB should be performed through the most direct approach to the tumor, and LSS can be performed safely through the standard approaches without excision of the biopsy tract.