To assist surgeons to select a total hip replacement (THR) we present comparative information on all such implants on the market in the UK. We identified 62 different primary THRs, manufactured by 19 companies; half had been introduced in the last five years, and only 30% have any results published in peer-reviewed journals. The prices range from 250 pounds to 2000 pounds, and the two cheapest implants have the longest reported follow-up. The number of THR implants available in the UK, and presumably the rest of the world, is rapidly increasing, but there is little or no scientific evidence that the newer, more expensive, implants are better than established designs. Some will undoubtedly be worse. We believe that this situation is unsatisfactory and make recommendations for improvement, in particular that preference be given to implants with good results in published peer-reviewed long-term clinical trials.

Cost is a factor in the choice of prosthetic components in joint replacement. For a given performance, the least expensive components are the most cost-effective. When evaluating a new prosthesis with an unknown outcome, the use of an economic model allows estimation of potential cost-effectiveness. We used published data for the survival of cemented total hip replacements from Sweden, and cost and demographic information from New South Wales, Australia, in such a model. In young active total hip recipients a new prosthetic design which offered a 90% improvement in survivorship over 15 years and a 15% reduction in the cost of revision surgery, could be sold at a price of 2 to 2.5 times that of conventional cemented components such as the Charnley Low Friction Arthroplasty and still be cost-effective. Using more likely estimates of the improved performance of new technology, however, the upper limit of cost-effectiveness is an increase of 1.5 to 1. Only a very small increase in the cost of a prosthesis could ever be justified for older patients of either sex. Most of the potential benefits of a better level of survivorship appear towards the end of the 15-year period. The results of modelling may be incorporated in clinical trial design. Given the known performance of some well-established and relatively inexpensive designs of prostheses, very large randomised studies would be required to prove an improvement in performance.

We present the 5.6- to 7.6-year results of our first 118 hydroxyapatite (HA)-coated total hip replacements in patients under 66 years of age. The titanium femoral component has proximal HA coating and was usually articulated with an HA-coated threaded cup. The HA coating of 50 microns thickness has a porosity of below 3%, 97% HA purity and 65% crystallinity. The survival rate at a mean of six years was 100% for the HA-coated stems and 99% for the HA-threaded cups. The average Harris hip score at one year was 96, and at three years and thereafter 98. There was a very low incidence of early pain after surgery. Serial radiographs showed rapid bony integration of implants with evidence of bone apposition on the coating within six months. By Engh's criteria, all the femoral components had confirmed bone ongrowth after three years. We found no deterioration of results with time, and consider that our clinical and radiological results show that HA coatings can provide early pain relief and durable implant fixation.

From 1981 to 1983, we implanted Bioceram type-4 and type-5 prostheses in 61 hips in 54 patients with osteoarthritis secondary to acetabular dysplasia, congenital subluxation, or congenital dislocation of the hip. Fifty-seven hips in 50 patients were followed for a mean of 11.1 years (10 to 13). The mean age of the patients at operation was 53 years (31 to 70). Functional evaluation using the Merle d'Aubigne and Postel hip score showed a 77% success rate. Radiological loosening occurred in three femoral (5%) and 16 acetabular components (28%). Autologous femoral head grafts were used in 18 hips and became incorporated, giving mechanical support to the socket except for one which occupied a large weight-bearing area and eventually collapsed. The mean polyethylene wear was 1.1 mm (0 to 3.6) and the mean wear rate was 0.10 mm/year (0 to 0.31). A high rate of wear correlated with calcar resorption (p > 0.002) but not with acetabular loosening. There was no breakage of a ceramic head. Study of the ceramic heads and polyethylene sockets retrieved after ten years showed excellent surface roughness, sphericity, and bending strength for the heads but scratches and voids were seen on the sockets.

We report a high rate of failure of the Ring polyethylene cementless cup caused largely by granulomatous osteolysis. We have reviewed 126 prostheses inserted from 1986 to 1992 at from 11 to 90 months after surgery. There was radiological evidence of osteolytic granulomas adjacent to the external surface of the cup in 32%, appearing on average at three years from operation. In a subgroup of 59 prostheses followed for at least four years the incidence of such changes was 54%. A total of 27 cups (22%) have required revision, 21 for granulomatous loosening at an average follow-up of five years. In the retrieved prostheses there was obvious polyethylene abrasion and histological examination confirmed the presence of polyethylene wear debris. We found no significant correlation of osteolysis with cup size, although smaller cups were predominant among those having revision.

We performed a prospective study on 96 patients with extra-articular or intra-articular fractures of the distal radius with a dorsally displaced posteromedial fragment. After closed reduction, we compared trans-styloid fixation and immobilisation with Kapandji fixation and early mobilisation. Forty-two patients of mean age 57.1 years +/- 18.1 (SD) were treated by trans-styloid K-wire fixation and 45 days of short-arm cast immobilisation. Fifty-four patients of mean age 57.7 years +/- 18.7 (SD) had Kapandji fixation and immediate mobilisation according to the originator. All the patients had clinical and radiological review at about six weeks and at 3, 6, 12 and 24 months after the operation. Pain, range of movement and grip strength were tested clinically, and changes in dorsal tilt, radial tilt, ulnar variance, and radial shortening were assessed radiologically. Statistical analysis was applied to comparisons with the normal opposite wrist. Pain and reflex sympathetic dystrophy were more frequent after Kapandji fixation and early mobilisation, but the range of motion was better although this became statistically insignificant after six weeks. The radiological reduction was better soon after Kapandji fixation, but there was some loss of reduction and increased radial shortening during the first three postoperative months. The clinical result at two years was similar in both groups.

The surgical approaches used to expose fractures of both bones of the forearm vary depending on the site and type of fracture and the degree of comminution; all have limitations. An exposure is described which allows access to most of the radius and ulna through a single skin incision.

We describe a new technique for open reduction, bone grafting and fixation with a single Kirschner wire of unstable fractures of the distal radius. Of the 83 patients treated by this technique, most had regained volar tilt when seen at an average of 13 months after injury. Malunion was seen in 18 patients due either to poor placement of the graft and Kirschner wire or because of both volar and dorsal comminution. Assessment of hand and wrist function showed an average recovery of 63% of mass grip strength with an excellent return of specialised grip strength and range of movement. The advantages of this technique over closed methods include the ability to regain the volar tilt of the distal radius and to achieve reduction at any time before union of the fracture.

We describe the results of treatment of open fractures of the humerus, radius and ulna in 61 children. Most were due to low-energy trauma and were rarely associated with head or other injuries; 72% were Gustilo type I, 15% type II and 13% type III. Fifteen children (25%) had open diaphyseal, supracondylar or T-shaped fractures of the humerus. Arterial injuries occurred in two (13%) and nerve injuries in 7 (47%). All nerve injuries recovered spontaneously. The long-term results in 13 children were excellent or good in 11 (85%) and fair in two (15%). Forty-six children (75%) had open forearm fractures. Arterial injuries occurred in one (2%), nerve injuries in five (11%) and a compartment syndrome in five (11%). Ruptured radial and ulnar arteries and median and ulnar nerves were repaired in one child. All other nerve injuries resolved spontaneously. Early compartment release in five children prevented Volkmann's ischaemic contracture. Normal union occurred in only 36 children (78%). Delayed union, nonunion, malunion and refracture frequently complicated type-II and type-III fractures of the shafts of the radius and ulna. The long-term results in 38 children were excellent or good in 33 (87%), fair in 4 (11%) and poor in one (2%). The short-term results for open fractures of the humerus were better than for open fractures of the forearm, but the long-term results were similar being excellent or good in 86% of the children.

Four patients who had injured the lower end of the humerus in childhood with resulting cubitus varus developed recurrent posterior dislocation of the head of the radius after further injury to the elbow. Dislocation occurred when the forearm was supinated and spontaneous reduction took place on pronation. At operation the lateral ligament complex was seen to be lax and elongated. After tightening of the ligament and with a supracondylar osteotomy of the humerus to correct the cubitus varus the recurrent dislocation was eliminated.

In a prospective study, we evaluated the clinical results of 23 patients with a cryopreserved non-tissue-antigen-matched meniscal transplant at a follow-up of from two to five years. These early results were satisfactory in 20 patients. Three transplantations failed and the allografts were removed after 12, 20 and 24 months. Post-transplantation arthroscopy showed that most meniscal transplants had healed to the knee capsule. Histological examination showed revascularisation of the transplant and evidence of viable meniscal chondrocytes. The failures were probably caused by malalignment, resulting in impaired revascularisation of the graft.

We performed electrophysiological studies on both legs of 52 children, aged from 3 months to 15 years, with idiopathic club foot. In only nine (17%) was no abnormality found. Isolated peroneal nerve damage was seen in 14 (27%). Abnormality of both peroneal and posterior tibial nerves was found in five (10%). Four patients (8%) had evidence of isolated spinal-cord dysfunction, whereas combined spinal-cord and peripheral-nerve lesions were seen in 14 (27%). Six patients (11%) had variable neurogenic electrophysiological patterns. In 13 patients in whom the studies were repeated neither progression nor improvement of the electrophysiological parameters was observed. Pathological electrophysiological findings were found in 66% of conservatively-treated patients. In the 43 patients treated surgically, all 16 with fair and poor results had pathological electrophysiological findings and 12 required further operations. Multiplicity of the pathological findings was related to the severity of the deformity of the foot; normal studies represent a good prognostic sign. Electrophysiological studies are useful in idiopathic club foot with residual deformities after conservative or operative treatment. Our findings support the theory that muscle imbalance is an aetiological factor in idiopathic club foot.

Congenital or acquired shortness of a metatarsal may cause pain in adjacent metatarsals. From 1983 to 1990, we performed nine metatarsal lengthenings in seven adolescent patients by metaphyseal osteotomy followed by gradual distraction of callus (callotasis). Two patients required bone grafts after the lengthening. We used a rigid, unilateral external fixator designed for use in the hand and foot. At follow-up, from three to ten years later, healing had been achieved in all with an average healing index of 50 days/cm, and metatarsalgia had been relieved by the restoration of correct metatarsal length.

From 1986 to 1991 we fitted 20 children with endoprostheses after resection of malignant bone tumours of the leg; six have reached skeletal maturity and are the subject of this study. Reconstruction of defects in growing limbs in which the eventual shortening can be predicted requires the use of extendable prostheses. The mean age at operation was 11 years (9.2 to 13.7) and the average follow-up period was 6.3 years (4.3 to 7.6). The diagnosis was osteosarcoma in five patients and Ewing's sarcoma in one. All tumours were Enneking stage-IIB. When seen for follow-up all patients were free from disease. The extendable implants used included the Pafford-Lewis prosthesis and the Kotz Modular Femur Tibia Reconstruction system with a compatible, newly-designed growth module. Telescope-like elongation of the prostheses was performed by insertion of a screwdriver through a small skin incision. Active epiphyseal growth in the adjacent growth plate was preserved by using prosthetic stems with a smooth surface. The mean length gained was 13.15 cm (4.5 to 19.5) requiring 53 planned procedures. Seven revision operations were necessary for complications. Functional evaluation showed excellent and good results in all cases. Stress-shielding at the site of anchorage of the prosthesis was more pronounced than in adults. Implantation of extendable endoprostheses in children provides a reasonable alternative to rotationplasty, but limb salvage requires more operations.

We reviewed 16 patients with spina bifida and unilateral dislocation of the hip at an average age of 17 years. Nine had a high neurological level (thoracic to L3) and seven a low lesion (L4 to sacral). We assessed the influence of unilateral dislocation of the hip on leg-length discrepancy, hip pain, hip stiffness and pressure sores of the ischial tuberosity. In non-walking patients with high-level lesions, unilateral dislocation gave little functional disability and did not appear to require reduction. In walking patients with low-level lesions, leg-length discrepancy led to a poor gait and functional problems which could be prevented by reduction of the dislocation. In all patients with low lesions, surgery was successful in maintaining reduction; in two of five patients with high lesions it was unsuccessful.

We investigated 185 adolescents under the age of 19 years with spondylolysis. All but five were active in sport. The pars defect was classified into early, progressive and terminal stages. Of the 346 pars defects in 185 patients, 39.6% were early, 29.5% progressive and 30.9% in the terminal stages. Conservative management produced healing in 73.0% of the early, 38.5% of the progressive and none of the terminal defects. These results suggest that spondylolysis is caused by repetitive microtrauma during growth and can be successfully treated conservatively if treatment is started in the early stage. There was elongation of the pars interarticularis as the pars defect progressed, and this is likely to be a consequence of the defect rather than a contributing cause.

We treated 137 patients with symptomatic lumbar disc prolapse by automated percutaneous lumbar discectomy (APLD). Seventeen (12%) required further operation. At a mean follow-up of 55 months, the success rate was 45%. Of those who had APLD alone, 52% were graded as either excellent or good. In this group, 76% were employed, and the mean Oswestry score was 28.2%. One-third of those patients initially rated as successful had deterioration in symptoms and increased disability from back pain. The Short Form 36 health survey questionnaire revealed that these patients had a chronic ill-health profile.

We used an experimental rabbit model of leg lengthening to study the morphology and function of muscle after different distraction rates. Lengthening was in twice-daily increments from 0.4 to 4 mm per day. New contractile tissue formed during lengthening, but some damage to the muscle fibres was seen even at rates of less than 1 mm per day; abnormalities increased with larger rates of lengthening. There was proliferation of fibrous tissue between the muscle fibres at distraction rates of over 1 mm per day. Active muscle function showed adaptation when the rate was 1.0 mm per day or less, but muscle compliance was normal only after rates of 0.4 mm per day. Muscle responded more favourably at rates of distraction slower than those shown to lead to the most prolific bone formation. At present the rate of distraction in clinical practice is determined mainly by factors which enhance osteogenesis. Our study suggests that it may be advisable to use a slower rate of elongation in patients with poor muscle compliance associated with the underlying pathology; this will allow better accommodation by the contractile and connective tissues of the muscles.

We performed single-photon-emission CT (SPECT) and planar bone scans to assess femoral head vascularity in ten patients with displaced intracapsular hip fracture. The heads were labelled with tetracycline and after excision at hemiarthroplasty were assessed for tetracycline uptake distribution by fluorescence under UV light. The four which had the greatest tetracycline uptake were normal on SPECT and planar imaging. In two cases the planar bone scans were normal although SPECT suggested avascularity thus giving false-negative results. Surgeons should be aware of this; SPECT may prove to be a more accurate method of assessing vascularity of the femoral head in fractures of the femoral neck.

The early diagnosis of aseptic loosening of a total hip replacement by plain radiography, scintigraphy and arthrography has been shown to be unreliable. It has been suggested that it may be possible to distinguish between a secure and a loose prosthesis using a vibration technique. We have assessed the use of this technique in vitro using models of early and late loosening. Late loosening with an unstable prosthesis can be reliably detected by vibration analysis, but this method was shown to have a very poor diagnostic sensitivity in early loosening when there is no obvious prosthetic instability.

We studied 56 patients with fractures of the tibial shaft in a multicentre prospective randomised trial of three methods of external fixation. Group I was treated with a fixator which was unlocked at 4 to 6 weeks to allow free axial compression (axial dynamisation) with weight-bearing. Group II was treated with a fixator that was similarly unlocked at 4 to 6 weeks but included a small silicone spring which on weight-bearing could be compressed by up to 2 mm. this spring returns to its original length on cessation of weight-bearing thus allowing cycles of motion of up to 2 mm. Group III had a spring fixator like group II, but it was unlocked from the start to allow cyclical micromovement as soon as weight-bearing began. Fracture healing was monitored by the measurement of fracture stiffness. We defined healing as achieving a stiffness of 15 Nm per degree. The mean time was 14.1 weeks in group I, 15.9 weeks in group II, and 19.3 weeks in group III. The difference between groups was statistically significant (p = 0.004). The 95% confidence intervals for the average delay in healing with early cyclical micromovement (group III) as compared with later axial dynamisation (group I) was 1.8 to 8.7 weeks. The healing time in patients whose cyclical micromovement was delayed for 4 to 6 weeks (group II) was between these two extremes, but the differences from either of the other groups could have been due to patient selection. In the patients who completed the full trial, there were pin-track infections in over 60% of those in the cyclical micromovement groups compared with 20% in the axial dynamisation group (p = 0.03).(ABSTRACT TRUNCATED AT 250 WORDS)

One method of reconstruction in limb salvage surgery for bone tumours is wide resection, extracorporeal devitalisation of the excised segment by autoclaving, and reimplantation of the segment. We have studied the changes in temperature in the medullary cavity, the head, the medial condyle and lateral condyle of calf femora during autoclaving at 134 degrees C in two different autoclaves. There were impressive differences of temperature at different sites. The most unfavourable position was the lateral condyle, which consists mainly of cancellous bone: a short programme of 11 minutes produced a lowest temperature in the series of only 45 degrees C, which may not be sufficient to kill all tumour cells.

The appearance and the biochemical, cytological and bacteriological findings were studied in synovial fluid obtained from the knees of 72 patients from south-west India. We report a group of 12 patients with 'eosinophilic synovitis'. In these patients, all below the age of 20 years with an acute onset of severe pain in the knee, there was a large effusion with painful limitation of movement. Their blood leucocyte count averaged 11,200 per mm3 with a mild eosinophilia of 6%. Biochemical examination of synovial fluid was normal, but cytology showed an increase in leucocytes ranging from 1200 to 20,500 (mean 9525) with between 75% and 90% of eosinophils in eight patients and 60% to 75% in four. All the patients responded well to a course of diethylcarbamazine.