The use of bisphosphonates in the treatment of avascular necrosis of the femoral head is an encouraging but relatively new option with most published data being derived from small trials with limited follow-up. We present a clinicoradiological analysis of 395 hips with avascular necrosis which were treated with oral
Post-operative migration of cemented acetabular components as
measured by radiostereometric analysis (RSA) has a strong predictive
power for late, aseptic loosening. Also, radiolucent lines predict
late loosening. Migration has been reduced by systemic bisphosphonate
treatment in randomised trials of hip and knee arthroplasty. Used
as a local treatment, a higher local dose of bisphosphonate can
be achieved without systemic exposure. We wished to see if this
principle could be applied usefully in total hip arthroplasty (THA). In this randomised placebo-controlled, double-blinded trial with
60 participants, we compressed gauze soaked in bisphosphonate solution
(ibandronate) or saline against the acetabular bone bed immediately
before cementing the acetabular component. RSA, classification of
radiolucent lines, the Harris Hip Score (HHS) and the Western Ontario McMasters
Universities Osteoarthritis Index (WOMAC) were carried out at three-,
six-, 12-, and 24-month follow-up.Aims
Patients and Methods
An 81-year-old woman presented with a fracture
in the left femur. She had well-fixed bilateral hip replacements
and had received long-term bisphosphonate treatment. Prolonged bisphosphonate
use has been recently linked with atypical subtrochanteric and diaphyseal
femoral fractures. While the current definition of an atypical fracture
of the femur excludes peri-prosthetic fractures, this case suggests
that they do occur and should be considered in patients with severe
osteopenia. Union of the fracture followed cessation of bisphosphonates
and treatment with teriparatide. Thus, this case calls into question
whether prophylactic intramedullary nailing is sufficient alone
to treat early or completed atypical femoral fractures.
Bisphosphonates reduce peri-prosthetic bone loss in the short term after total hip replacement but the mid- and longer term effects are not known. The aims of this randomised trial were to examine the effect of a single dose of 90 mg of pamidronate on the clinical and radiological outcome and peri-prosthetic bone mineral density in 50 patients (56 hips) over a five-year period, following total hip replacement. At five years, 37 patients (42 hips) returned for assessment. The Harris hip scores were similar in the pamidronate and placebo groups throughout the study. Also at five years, four patients, two from each group had osteolytic lesions on plain radiography. These were located around the acetabular component in three patients and in the femoral calcar in one. The femoral and acetabular peri-prosthetic bone mineral density in the pamidronate group and the control group was similar at five years. Pamidronate given as a single post-operative dose does not appear to influence the clinical outcome or prevent the development of osteolytic lesions at five years after total hip replacement.
We performed 96 Birmingham resurfacing arthroplasties of the hip in 71 consecutive patients with avascular necrosis of the femoral head. A modified neck-capsule-preserving approach was used which is described in detail. The University of California, Los Angeles outcome score, the radiological parameters and survival rates were assessed. The mean follow-up was for 5.4 years (4.0 to 8.1). All the patients remained active with a mean University of California, Los Angeles activity score of 6.86 (6 to 9). Three hips failed, giving a cumulative survival rate of 95.4%. With failure of the femoral component as the endpoint, the cumulative survival rate was 98.0%. We also describe the combined abduction-valgus angle of the bearing couple, which is the sum of the inclination angle of the acetabular component and the stem-shaft angle, as an index of the optimum positioning of the components in the coronal plane. Using a modified surgical technique, it is possible to preserve the femoral head in avascular necrosis by performing hip resurfacing in patients with good results.