Gender differences in distal femoral morphology and the role of gender specific implants in total knee replacement: a prospective clinical study.

Gender differences in distal femoral morphology may affect femoral component fit using a standard range of prostheses. The clinical relevance of this is controversial. Standardised measurements were taken from the distal femora of 50 males and 50 females during total knee replacement (TKR). Corresponding measurements were taken from the respective gender specific and standard femoral components. No demographic differences were noted. Significant differences in both frequency and magnitude existed in the medial-lateral femoral component overhang between the sexes. In females, standard implants overhung at the anterior flange width (AFW) by >2mm in 24/50 (48%) and by >3mm in 17/50 (34%) (p<0.001). Also at the anterior medial-lateral width (MLA) 29/50 (58%) overhung by >2mm and 24/50 (48%) by >3mm (p<0.001). In males, standard implants overhung by >2mm in 1/50 (2%). In females, gender specific implants overhung by >2mm in 3/50 (6%). Females had a mean aspect ratio of 1.02 (0.82 to 1.35) and men 0.98 (0.79 to 1.19). Femoral component overhang can occur in females undergoing TKR and a gender specific implant would reduce the potential for medial-lateral overhang. Long term studies are awaited to quantify the clinical implications of overhang.

Tricortical bone graft for primary reconstruction of comminuted distal humerus fractures.

A tricortical bone graft harvested from the ilium was used to reconstruct a severely comminuted open intra-articular distal humerus fracture in an adult patient. The patient demonstrated a satisfactory functional and radiologic outcome despite loss of the lateral trochlear lip. When the lateral portion of the fractured trochlea cannot be repaired, excision of the fragments and insertion of an autogenous corticocancellous bone graft from the iliac crest can restore satisfactory function, even in the setting of an open fracture provided there is limited contamination and tissue devitalization. Radiocapitellar contact may be essential to good elbow function in this situation, because the corticocancellous bone graft does not restore the important lateral lip of the trochlea.

Optimum configuration of cannulated hip screws for the fixation of intracapsular hip fractures: a biomechanical study.

The radiographs of a sample of patients who had canulated hip screw fixation for intracapsular femoral neck fractures were reviewed in our region. There were six different types of configurations used in these fixations which are divided into two groups: (I) triangular configurations, consisting of two parallel screws with a third screw placed either superiorly, inferiorly, anteriorly or posteriorly; and (II) linear configurations with two or three screws in a vertical line. In our study, we tested the relative strength of each configuration in a laboratory setting using synthetic bone models. Statistical analysis, at 5% significance level, using two-way ANOVA and post-hoc test was carried out to test the differences of the results between the configurations.Our results clearly show that the triangular configurations had a higher peak load, higher ultimate load, less displacement and more energy absorption before failure than other configurations.

The AO/ASIF proximal femoral nail (PFN) for the treatment of unstable trochanteric femoral fracture.

The AO/ASIF proximal femoral nail (PFN) is a new device designed for the treatment of the unstable trochanteric femoral fracture. This study reports the outcome in such fractures treated using the PFN at a District General Hospital. All patients presenting to our department with unstable trochanteric femoral fractures were treated operatively using the PFN. A total of 76 patients were included in the study and were followed up to fracture union or fixation failure. A case documentation form and follow-up form were used to collect the data which included the Salvati and Wilson assessment of hip function. The majority of the procedures were reported by the operating surgeon as "easy" or "usual". Distal locking was difficult in three patients. In one patient, the fixation failed because the screws were wrongly positioned and was revised to a THR. Mortality rate, during the first 3 months, was 27%. Of the surviving patients, screws cut through the femoral head in four patients (8%), however, fractures united in all the patients. There was one incidence of fracture around the tip of the nail. Seventy-eight percent of the patients at the final follow-up scored >20 points (out of 40 points), using the Salvati and Wilson hip function scoring system. According to the patients and/or their carers, outcome was described as good or very good in 94% of the patients and the level of function was similar to pre-injury level in 50% of the patients. We conclude that the PFN is a useful device in the treatment of the unstable trochanteric femoral fracture. It is a relatively easy procedure and a biomechanically stable construct allowing early weight bearing. Femoral neck screws positioning is critical.