Objectives

Bisphosphonates are widely used as first-line treatment for primary and secondary prevention of fragility fractures. Whilst they have proved effective in this role, there is growing concern over their long-term use, with much evidence linking bisphosphonate-related suppression of bone remodelling to an increased risk of atypical subtrochanteric fractures of the femur (AFFs). The objective of this article is to review this evidence, while presenting the current available strategies for the management of AFFs.

Introduction: The objective of our study was to analyse the incidence of subsidence of an uncemented, hydroxyapatite coated, collarless prosthesis (Orthodynamics) and its impact on postoperative mobility in patients with fractured neck of femur.

Methods: 22 sets of case notes and X Rays were available for patients treated with the Orthodynamics hemiarthroplasty between February and November 2005. The mean age was 78 years (range 61 – 91 years). Analysis of standardised anteroposterior radiographs in the immediate postoperative period and at a mean interval of 14 weeks (ranging from 6 weeks to 64 weeks) was undertaken. Subsidence was calculated by measuring the reduction in the distance between the tip of lesser trochanter and a fixed point on the prosthesis.

Results: 18 of the 22 (81.8 %) cases showed subsidence of the prosthesis. The mean subsidence calculated was 9.1 millimetres (range 1 to 25 millimetres) and it showed no relationship to the postoperative interval at which it was calculated. Impact of subsidence on mobility state was assessed. Post operative mobility status was available for sixteen patients. Nine patients showed no change in the mobility at follow up. This group had a mean subsidence of 4.3 mm. Seven patients had a worsening of their mobility state. The mean subsidence in this group was 10.1 mm.

Discussion: Our study shows significant subsidence of an uncemented, collarless, hydroxyapatite coated prosthesis used for hip hemiarthroplasty and an associated worsening of mobility. We suggest that further review of this prosthesis is done and other proven prostheses used for hip hemiarthroplasty after a fractured neck of femur.

Introduction: Osseointegration is known to occur around the uncemented acetabular cups which results in fill-in of peri-acetabular gaps. The objective of this study was to assess the gaps around uncemented acetabular cups radiologically in early post-operative period.

Methods: 53 primary uncemented total hip arthroplasties were performed at our hospital by a single surgeon between February 2003 and august 2005. There were 29 females and 22 males. Two patients had bilateral surgeries. Mean age of patients was 70 years (range, 52–88 years). Primary osteoarthritis of the hip was the indication for surgery in all the patients. Peri-acetabular gaps were measured on the radiographs taken at day-1 post-operatively and at 3 months follow-up. All the measurements were taken independently by two investigators on two different occasions using a picture archiving & communications (PACS) system. The two sets of data from each investigator were compared for intra and inter-observer variability using independent-samples t test.

Results: in 24 cases, no gaps were found around the ace-tabular cups on day-1 post-operative radiographs. In 29 cases, the mean gap was 4 mm (range, 1–8 mm) on postoperative day-1. Five gaps were in zone one, 24 in zone two and none in zone three. At 3 months follow-up, the mean gap was found to be 0.6 mm (range, 0–3 mm). The reduction in gaps from day-1 post-op to 3 months follow-up was statistically significant (chi square test, p< 0.05).

Discussion: We found a significant reduction in peri-acetabular gaps as early as at 3 months following uncemented total hip arthroplasties. We feel that settling of the cup within the acetabulum is responsible, rather than osseointegration, for these fill-in of gaps in early postoperative period. A larger study is required to analyse this phenomenon as screws fixation of uncemented cups may compromise their settling within the acetabulum.

Objective : The valgus angle of the distal femur determines the axial alignment of limb. It is used to plan the realignment osteotomies in limb reconstruction surgery and to determine the angle of resection of the distal femur in total knee arthroplasty. The objective of this study was to analyse the variation of the valgus angle of the distal femur in a random Caucasian population with osteoarthritic knees presenting for total knee arthroplasty.

Method : A prospective study was undertaken involving a review of pre-operative CT scout films of osteoarthritic knees in 83 consecutive patients (44 males and 39 females; mean age 70.2 years) presented for total knee arthroplasty between May 1999 and October 2002. The valgus angle was calculated from the difference between the anatomical and mechanical axes of femur plotted on CT scanogram films.

Results : Mean valgus angle was 5.4 degrees (range 3.3 to 7.6 degrees) with a standard deviation of 1.1 degrees. Estimated 95% confidence interval of the mean for the population was 3.6 – 7.4 degrees. There were no significant differences for age, gender or laterality of the limb.

Conclusion : The value of mean valgus angle of the distal femur in osteoarthritic knees was found to be significantly lower than the one quoted in the literature in normal disease-free knees. This may have important implications on the preoperative planning of appropriate surgical planes for total knee arthroplasty or corrective osteotomies.