Severe acetabular fractures are difficult to treat. Complications include blood loss, neural damage, long operating times, and a high risk of sepsis and failure. Even when the fracture is ideally stabilised, there is a major risk of secondary osteoarthritis. This can be related to bone necrosis, cartilage surface damage, bone loss.

However, even in young patients modern surgical techniques, including use of an alumina-against-alumina bearing, may facilitate long-term survival without limitation of activity.

Functionally, the results of secondary procedures after failed osteosynthesis are statistically worse than after primary total hip arthroplasty (THA). The surgery is difficult because of material retrieval difficulties, nerve dissection, bone reconstruction and remaining muscular dysfunction.

We reviewed the results of 80 THA procedures done between 1980 and 1998 to treat 58 acetabular fractures. The mean age of our 57 patients (39 men and 18 women) was 50 years (21 to 80). The mean delay between fracture and THA was 10 years in 22 patients who had undergone osteosynthesis and six years in 35 patients who had been treated conservatively. The mean follow-up period was 5,5 years (6 months to 20 years).

There were eight instances of socket loosening, two of which were septic and six aseptic. Two of these patients had screw-in prostheses and six had cemented. There were 19 sciatic palsies, 13 of which developed after trauma, four after osteosynthesis and two after THA. There were three cases of gluteus medius palsy. In two of four cases of sepsis that occurred after osteosynthesis, sepsis recurred after THA, and in one patient sepsis developed after THA.

In this limited series, patients who underwent THA after osteosynthesis did not have as good an outcome as those in whom initial orthopaedic treatment was followed some weeks later by THA. We believe many poor results could have been avoided with better primary surgery. Functional results are likely to be better, and the incidence of complications lower, if primary THA is performed in conjunction with acetabular reconstruction. Of course, for treatment of simple acetabular fracture involving major displacement of the posterior wall, one column osteosynthesis is still recommended.

Alumina-on-alumina bearings in total hip arthroplasty (THA) were introduced about 30 years ago. Theoretically, their excellent tribological properties and low debris generation provide a solution to osteolysis. The 24-year experience of the Paris group suggests that osteolysis is no longer a problem. Any need for revision was related to mechanical failure rather than to debris, except in a few cases in which a pros-thesis that had been loose for many years resulting in metal-on-ceramic impingement.

Cemented socket and screw-in ring metal-backed alumina yielded poor results. The recent improvements in alumina quality and in ceramic fixation, using cementless fully coated hydroxyapatite material, may provide a solution in active young patients. Preliminary results of the first 100 THA procedures using a cementless stem and socket and 32-mm alumina head, and alumina liner secured with a Morse taper, are very encouraging. One socket required revision because of poor initial surgery in a severe acetabular fracture. Patients ranged in age from 14 to 71 years (median 45 years).

We have carried out a prospective, randomised study designed to compare the long-term stability of the stem of cementless femoral implants with differing surface configurations. A total of 50 hips (46 patients) was randomised into two groups, according to whether the medullary stem had been grit blasted (GB) or coated with hydroxyapatite (HA). Both femoral prostheses were of the same geometrical design. We used Ein Bild Roentgen Analyse femoral component analysis (EBRA-FCA) to assess the stability of the stem. The mean follow-up was for 8.66 years.

The mean migration of the stem was 1.26 mm in the HA group compared with 2.57 mm in the GB group (Mann-Whitney U test, p = 0.04). A mixed model ANOVA showed that the development of subsidence was statistically different in the two groups during the first 24 months. After this subsidence increased in both groups with no difference between them. Our results indicate that, with the same design of stem, HA coating enhanced the stability of the femoral stem when compared with GB stems.

We compared and quantified the modes of failure and patterns of wear of 11 Mittelmeier and 11 Ceraver-Ostal retrieved alumina-alumina hip prostheses with reference to the corresponding clinical and radiological histories.

Macroscopic wear was assessed using a three-dimensional co-ordinate measuring machine. Talysurf contacting profilometry was used to measure surface roughness on a microscopic scale and SEM to determine mechanisms of wear at the submicron level.

The components were classified into one of three categories of wear: low (no visible/measurable wear), stripe (elliptical wear stripe on the heads and larger worn areas on the cups) and severe (macroscopic wear, large volumes of material lost). Overall, the volumetric wear of the alumina-alumina prostheses was substantially less than the widely used metal and ceramic-on-polyethylene combinations. By identifying and eliminating the factors which accelerate wear, it is expected that the lifetime of these devices can be further increased.

Limited success in regenerating large bone defects has been achieved by bridging them with osteoconductive materials. These substitutes lack the osteogenic and osteoinductive properties of bone autograft. A direct approach would be to stimulate osteogenesis in these biomaterials by the addition of fresh bone-marrow cells (BMC).

We therefore created osteoperiosteal gaps 2 cm wide in the ulna of adult rabbits and either bridged them with coral alone (CC), coral supplemented with BMC, or left them empty. Coral was chosen as a scaffold because of its good biocompatibility and resorbability. In osteoperiosteal gaps bridged with coral only, the coral was invaded chiefly by fibrous tissue. It was insufficient to produce union after two months. In defects filled with coral and BMC an increase in osteogenesis was observed and the bone surface area was significantly higher compared with defects filled with coral alone. Bony union occurred in six out of six defects filled with coral and BMC after two months. An increase in the resorption of coral was also observed, suggesting that resorbing cells or their progenitors were present in bone marrow and survived the grafting procedure. Our findings have shown that supplementation of coral with BMC increased both the resorption of material and osteogenesis in defects of a clinical significance.

We made a semiquantitative study of the comparative histology of pseudomembranes from 12 loose cemented ceramic-ceramic and 18 metal-polyethylene total hip replacements. We found no significant difference in cellular reaction between the two groups, but there was a major difference in the origin of the particulate debris. In the metal-polyethylene group, polyethylene of articular origin was predominant, while in the ceramic-ceramic group the cellular reaction appeared to be a response to zirconia ceramic particles used to opacify cement used for fixation.

Isolation and characterisation of the debris showed that the zirconia particles formed the greatest proportion (76%) in ceramic-ceramic hips, while alumina debris of articular origin formed only 12%.

Our study has indicated that aseptic loosening of ceramic cups is not due to a response to debris generated at the articular interface, but to mechanical factors which lead to fragmentation of the cement.

After an allogenic bone-marrow transplant, a vascular necrosis of the femoral head may affect young adults, producing destructive lesions which require hip replacement. We have reviewed 27 consecutive such total hip arthroplasties (THA) at a minimal follow-up of two years. Of these, 20 were primary operations for Ficat (1985) stage-III and stage-IV lesions, and seven were revisions after the failure of previous surgery. The median age at operation was 30 years (17.5 to 44). The prostheses had a cemented, collared titanium-alloy stem, an alumina-alumina joint, and a press-fit socket. Seven had a titanium-alloy metal back and 20 had all-alumina cups of which six had to be cemented.

At an average follow-up of five years, no patient had been lost to follow-up. One had died from septicaemia after two years and another with chronic graft-versus-host disease developed a deep infection 2.5 years postoperatively and had a successful revision. There were no revisions for aseptic loosening. The clinical results on the Merle d’Aubigné and Postel (1954) scale were very good or excellent in 23 hips (88%), good in one and fair in two. Ten hips showed incomplete acetabular radiolucencies less than 1 mm thick, but there were no radiolucent lines around the stems.

We conclude that for these difficult patients THA with ceramic joints and careful technique provides the best short- and medium-term option after the failure of medical treatment.

We report 17 patients who had grafting of the common peroneal nerve after traction injuries. Sixteen were reviewed at a median follow-up of 36 months. The nerve gap ranged from 7 to 20 cm. A functionally satisfactory result was achieved in six patients (37.5%), a fair result in six and a poor result in four. Seven patients had, in addition, a posterior tibialis tendon transfer; this improved the result in five. Grafting produced some satisfactory results even when the nerve gap was as long as 20 cm.

Total hip replacement using an alumina head and socket and a titanium alloy stem is evaluated in a series of patients under 50 years of age. Between April 1977 and December 1986, 86 such replacements were performed in 75 patients, but mainly because patients had difficulty travelling from Africa, only 71 hips were followed up adequately; of these, 56 were primary procedures and 15 revisions. Survivorship analysis showed that 98% of the prostheses were retained for 10 years. On clinical and radiological examination 51 of the 71 hips were stable and acceptable, 15 had radiological changes on the acetabular side, and one on the femoral side; four other cases had clinical and radiological changes suggesting impending failure, possibly because fixation of the socket was inadequate. There were no differences between the results of the primary procedures and those of revisions. In these young patients, the results seem better with alumina-on-alumina hips than with other varieties, possibly because of their remarkably low wear.

Between October 1972 and December 1980, 139 post-traumatic brachial plexus palsies were operated upon by the same surgeon. The results of 63 are reported with a follow up of at least three years for the 32 complete palsies and two years for the 31 partial palsies. The protocol for examination and surgical repair is described. Major repairs were performed in 48, including suture, interfascicular grafting and nerve transfer. The remaining 15 had a neurolysis. The results are given for each type of lesion and for each kind of repair. Two series of complete palsies, one treated operatively, the other conservatively, are compared. It is concluded that surgical repair gives good results in partial palsies and in some complete palsies. Nerve transfer or graft gives some improvement but the usefulness of the limb remains disappointing.