Clinical and radiological outcome of combined femoral and Chiari osteotomies for subluxed or dislocated hips secondary to neuromuscular conditions: a minimum of 10-year follow-up.

We evaluated the medium-term results of combined Chiari pelvic and femoral osteotomies performed at the Manchester Children's Hospitals between the years 1985 and 1994. The indications for these osteotomies were either hip dislocation or subluxation in children with neuromuscular disease. We clinically and radiologically evaluated 20 hips in 18 patients treated for hip subluxation and dislocation with Chiari osteotomy. The average post-operative clinical follow-up period was 11.32 years (range 10.1-12.9). The mean age at the time of surgery was 7.3 years (range 3.1-13.2 years). Clinically, 9 hips had a 'Good' outcome, 10 were "Fair" and 1 was "Poor" according to Osterkamp criteria. At last follow-up, radiologically the mean Sharp's angle improved from 51° to 44° (p = 0.09), the mean Centre-Edge angle improved from -16° to 18° (p = 0.067), the mean Migration Index improved from 59 to 29 % (p = 0.011), the mean femoral neck-shaft angle from 160° to 117° (p < 0.0001) and the Severin criteria improved from an average grade of 4.5-2.9 (p < 0.0001). Our results compared to previous studies confirm that combined femoral and Chiari osteotomies provide a favourable outcome both clinically and radiologically at least 10 years following surgery. Accepting that the numbers are small, we report no statistical difference in the mean age at the time of operation when comparing the children with an eventual 'good' outcome and those with an eventual 'fair' or 'poor' outcome.

Operative treatment for hip subluxation in spinal muscular atrophy.

Subluxation of the hip is common in patients with intermediate spinal muscular atrophy. This retrospective study aimed to investigate the influence of surgery on pain and function, as well as the natural history of subluxed hips which were treated conservatively. Thirty patients were assessed clinically and radiologically. Of the nine who underwent surgery only one reported satisfaction and four had recurrent subluxation. Of the 21 patients who had no surgery, 18 had subluxation at the latest follow-up, but only one reported pain in the hip. We conclude that surgery for subluxation of the hip in these patients is not justified.

Effect of a bisphosphonate, disodium pamidronate, on the quasi-static flexural properties of Palacos R acrylic bone cement.

Aseptic loosening is a major complication of joint replacements and is thought to be associated with a heavy macrophage infiltrate in response to wear particles. Bisphosphonates are compounds known to inhibit osteoclastic activity and are used to reduce osteolysis in Paget's disease, osteoporosis, and metastatic bone disease. Oral bisphosphonates have also been used to decrease osteolysis and therefore prevent aseptic loosening of joint replacements. It has been suggested that bisphosphonates mixed in bone cement can reduce bone resorption in joint replacement surgery. This would be an excellent therapeutic option to prevent or control osteolysis. The present aim was to study the mechanical properties of a commercially available acrylic bone cement, Palacos R, mixed with the bisphosphonate pamidronate. The liquid monomer of Palacos R was mixed with liquid pamidronate. Two groups of bone-cement strips were produced, one with added pamidronate and one without. The flexural properties of the cement strips were examined. A significant reduction in both the bending modulus and bending strength of the specimens with added pamidronate was found. In conclusion, the use of liquid pamidronate mixed with the acrylic bone cement Palacos R in order to reduce osteolysis is not recommended because of its effect on the mechanical properties of Palacos R.

Progression of scoliosis after spinal fusion in Duchenne's muscular dystrophy.

A consecutive series of 85 patients with Duchenne's muscular dystrophy who underwent spinal fusion over a period of 16 years was followed up with regard to the progression of the scoliosis and pelvic obliquity. Of 74 patients with adequate radiographic follow-up, 55 were instrumented with the Luque single-unit rod system and 19 with the Isola pedicle screw system; seven were instrumented to L3/4, 42 to L5, 15 to S1 and 10 to the pelvis with intrailiac rods. The mean period of follow-up was 49 months (SD 22) before and 47 months (SD 24) after operation. There was one peri-operative death and three cases of failure of hardware. The mean improvement in the Cobb angle was 26 degrees and in pelvic obliquity, 9.2 degrees. Fusion to L3/4 achieved a poorer correction of both curves while intrapelvic rods, achieved and maintained the best correction of pelvic obliquity. Fusion to S1 did not provide any benefit over more proximal fusion excluding the sacrum, with regard to correction and maintenance of both angles. The Isola system appeared to provide and maintain a slightly better correction of the Cobb angle.