ACL reconstruction using hamstring tendons has gained general acceptance. However, it has been recommended to seek a tight fit of the tendon in the bone canal in order to provide circumferential contact and healing of the graft, and to prevent secondary tunnel widening. Recent findings show, that the graft dynamically adapts to pressure in the canal resulting in a potentially loose graft-bone contact. It was the goal of this study to understand the viscoelastic behaviour of hamstring grafts under pressure and to develop a new method for tendon pre-conditioning to reduce the graft volume before implantation, in order to reduce the necessary bone canal diameter to accommodate the same graft. Flexor digitorum tendons of calf and extensor digitorum tendons of adult sheep were identified to be suitable as ACL grafts substitutes for human hamstring tendons in vitro. The effect of different compression forces on dimensions and weight of the grafts were determined. Further, different strain rates (1mm/min vs 10mm/min), compression methods (steady compression vs. creep) and different compression durations(1, 5, 10min) were tested to identify the most effective combination to reduce graft size by preserving its macroscopic structure.Introduction
Material and Methods
We have reviewed a group of patients with iliopsoas impingement after total hip replacement with radiological evidence of a well-fixed malpositioned or oversized acetabular component. A consecutive series of 29 patients (30 hips) was assessed. All had undergone a trial of conservative management with no improvement in their symptoms. Eight patients (eight hips) preferred continued conservative management (group 1), and 22 hips had either an iliopsoas tenotomy (group 2) or revision of the acetabular component and debridement of the tendon (group 3), based on clinical and radiological findings. Patients were followed clinically for at least two years, and 19 of the 22 patients (86.4%) who had surgery were contacted by phone at a mean of 7.8 years (5 to 9) post-operatively. Conservative management failed in all eight hips. At the final follow-up, operative treatment resulted in relief of pain in 18 of 22 hips (81.8%), with one hip in group 2 and three in group 3 with continuing symptoms. The Harris Hip Score was significantly better in the combined groups 2 and 3 than in group 1. There was a significant rate of complications in group 3. This group initially had better functional scores, but at final follow-up these were no different from those in group 2. Tenotomy of the iliopsoas and revision of the acetabular component are both successful surgical options. Iliopsoas tenotomy provided the same functional results as revision of the acetabular component and avoided the risks of the latter procedure.
