Clinical and radiological assessments were carried out before surgery and at 6 months and one year after surgery and annually thereafter until the death of the patient or the revision of one or both components, the mean follow-up being 8.9 years (S.D. 5.6). The survival statistics are based on Kaplan-Meier survival curves and Cox regression analysis applied to 3 Groups with differing end-points: 1) Revision of one or both components of the prosthesis 2) Ditto or the development of a complication, seriously threatening the survival of the arthroplasty and 3) As in (2) or definite evidence of progressive radiological loosening.
For Group 1: the survivorship at 5, 10, 15 &
20 years was 95, 89, 82, &
81% respectively; for Group 2: 93, 87, 76 &
69%; and for Group 3: 91, 84, 72, &
68%. In Group 1, indications for revision or removal of one or both components were persistent dislocation (5), fracture (5), aseptic loosening complicated in some cases by fracture (20) and infection (14). In Group 2 the threatening complications included instability (2), un-united fracture of the ulna (4), infection (7), and clinical loosening (2)
The results with the long-stemmed implants showed a very similar trend, the important Zones being 2B, 4B, and 3.
Hyperphosphatasia, or hereditary bone dysplasia with hyperphosphatasaemia, is a rare genetic disorder which is characterised by failure to transform woven into lamellar bone. Clinical, radiological and histological features establish the diagnosis, fractures, deformities, diffuse sclerosis on radiographs and high serum alkaline phosphatase being characteristic. We report the case of a 27-year-old man with follow-up at the same hospital for 20 years. Attempts at treatment with calcitonin and disocium etidronate (EHDP) failed, but stapling of the growth plates at the knee was successfully performed. Transverse "brittle" fractures of the humerus, lower leg and ribs healed normally, but internal fixation and late bone grafting were required for a subtrochanteric stress fracture of the femur at the age of 24 years. At present the patient has no clinical problems and leads a normal life.