The fatigue failure of bone cement, leading to loosening of the stem, is likely to be one mode of failure of cemented total hip replacements. There is strong evidence that cracks in the cement are initiated at voids which act as stress risers, particularly at the cement-stem interface. The preferential formation of voids at this site results from shrinkage during polymerisation and the initiation of this process at the warmer cement-bone interface, which causes bone cement to shrink away from the stem. A reversal of the direction of polymerisation would shrink the cement on to the stem and reduce or eliminate the formation of voids at this interface.

We have investigated this by implanting hip prostheses, at room temperature or preheated to 44°C, into human cadaver femora kept at 37°C. Two types of bone cement were either hand-mixed or vacuum-mixed before implantation. We found that the area of porosity at the cement-stem interface was dramatically reduced by preheating the stem and that the preheating temperature of 44°C determined by computer analysis of transient heat transfer was the minimum required to induce initial polymerisation at the cement-stem interface. Temperature measurements taken during these experiments in vitro showed that preheating of the stem caused a negligible increase in the temperature of the bone. Reduction of porosity at the cement-stem interface could significantly increase the life of hip arthroplasties.

We studied the various drill bits available for engineering purposes, and compared them with standard orthopaedic drill bits, using continuous temperature recording at 0.5 mm, 1.0 mm and 1.5 mm from the edge of a 2.5 mm hole as it was drilled in fresh cadaver human tibia.

We found that some commercially available drill bits performed better than their orthopaedic equivalents, producing significantly less thermal injury to the surrounding bone and halving the force required for cortical penetration. Our work suggests that the optimal bit for orthopaedic purposes should have a split point and a quick helix. Theoretical knowledge of cutting technology predicts that the addition of a parabolic flute will further reduce thermal damage. Further work is being done on other drill sizes used in orthopaedic practice and on new custom-designed bits.

There have been conflicting reports on the effects of gamma irradiation on the material properties of cortical allograft bone. To investigate changes which result from the method of preparation, test samples must be produced with similar mechanical properties to minimise variations other than those resulting from treatment.

We describe a new method for the comparative measurement of bone strength using standard bone samples. We used 233 samples from six cadavers to study the effects of irradiation at a standard dose (28 kGy) alone and combined with deep freezing. We also investigated the effects of varying the dose from 6.8 to 60 kGy (n = 132).

None of the treatments had any effect on the elastic behaviour of the samples, but there was a reduction in strength to 64% of control values (p < 0.01) after irradiation with 28 kGy. There was also a dose-dependent reduction in strength and in the ability of the samples to absorb work before failure

We suggest that irradiation may cause an alteration in the bone matrix of allograft bone, but provided it is used in situations in which loading is within its elastic region, then failure should not occur.

Foreign-body reaction to polyglycolide (PGA) implants has been described in man. Many animal experiments have verified the mechanical properties of fixation devices made from PGA, but a significant foreign-body reaction has not been described. We studied the effect of PGA rods in 12 sheep with standardized osteochondral fractures of the medial femoral condyle fixed with uncoloured, self-reinforced PGA rods (Biofix). Radiographs were taken at intervals ranging from two weeks to two years, and the sheep were killed at intervals ranging from six to 24 months. All knees were examined histologically.

Eleven of the 12 fractures healed radiologically and histologically. Moderate to severe osteolysis was seen at four to six weeks with maximum changes at 12 weeks in ten animals. Six knees showed fistula-like connections between the implant site and the joint space. Three developed synovitis, one with inflammatory changes involving the whole cartilage and one with destruction of the medial condyle.

Although in our study osteochondral fractures fixed with PGA rods healed reliably, there were frequent, significant foreign-body reactions. Caution is needed when considering the use of PGA fixation devices in vulnerable regions such as the knee.

Bone growth into cementless prosthetic components is compromised by osteoporosis, by any gap between the implant and the bone, by micromotion, and after the revision of failed prostheses. Recombinant human transforming growth factor-β1 (rhTGF-β1) has recently been shown to be a potent stimulator of bone healing and bone formation in various models in vivo.

We have investigated the potential of rhTGF-β1, adsorbed on to weight-loaded tricalcium phosphate (TCP) coated implants, to enhance bone ongrowth and mechanical fixation. We inserted cylindrical grit-blasted titanium alloy implants bilaterally into the weight-bearing part of the medial femoral condyles of ten skeletally mature dogs. The implants were mounted on special devices which ensured stable weight-loading during each gait cycle. All implants were initially surrounded by a 0.75 mm gap and were coated with TCP ceramic.

Each animal received two implants, one with 0.3 μg rhTGF-β1 adsorbed on the ceramic surface and the other without growth factor. Histological analysis showed that bone ongrowth was significantly increased from 22 ± 5.6% bone-implant contact in the control group to 36 ± 2.9% in the rhTGF-β stimulated group, an increase of 59%. The volume of bone in the gap was increased by 16% in rhTGF-β1-stimulated TCP-coated implants, but this difference was not significant. Mechanical push-out tests showed no difference in fixation of the implant between the two groups. Our study suggests that rhTGF-β1 adsorbed on TCP-ceramic-coated implants can enhance bone ongrowth.

During a four-month period we observed 12 stress fractures of the inferior pubic ramus in 11 military recruits undergoing basic training. Eleven of these were in women. This high number was considered to be caused by the introduction of mixed training of male and female recruits; this forces women to increase their stride length when marching.

The presenting symptom was chronic groin pain which failed to settle with rest, and the clinical diagnoses were confirmed by radiographs in all but one patient who was diagnosed by ^99mTc bone scanning. Since the required stride length has been reduced there have been no new cases of stress fracture of the pelvis.

The Medoff sliding plate (MSP) is a new device used to treat intertrochanteric and subtrochanteric fractures. There are three options for sliding; either along the shaft or the neck of the femur, or a combination of both.

In a prospective series of 108 consecutive displaced intertrochanteric fractures we used combined dynamic compression. The patients were followed clinically and radiologically for one year. All fractures healed during the follow-up period. The only postoperative technical failure was one lag-screw penetration.

Combined compression of the MSP gives increased dynamic capacity which reduces the risk of complications. The low rate of technical failure in our series compares favourably with that of the sliding hip screw or the Gamma nail but randomised trials comparing the MSP with other hip screw systems are necessary to find the true role of the MSP with its various sliding modes.

We performed a randomised prospective trial to compare a cemented unipolar prosthesis (Thompson) with a cemented bipolar prosthesis (Monk) in the treatment of displaced intracapsular fractures of the hip in patients over 80 years of age. Patients with a mental test score of less than 5/13 were excluded but the mortality was still about 30% at one year in both groups. We therefore feel that subjective criteria such as the level of pain and the return to the preinjury state are of paramount importance.

Two years after operation there was no statistical difference between the rate of complications in the two groups. After adjusting for confounding factors such as differences in the level of function before injury between the groups, the degree of return to the preinjury state was significantly greater (p = 0.04) when using the unipolar prosthesis, which is one-quarter of the price of the bipolar.

We cannot therefore justify the use of an expensive bipolar prosthesis in patients over 80 years of age.

In a prospective, randomised trial of 81 patients with fractures of the ankle of AO types A, B and C we compared two regimes of postoperative management after internal fixation. The patients were mobilised either non-weight-bearing with crutches or weight-bearing in a below-knee walking plaster.

We found a temporary benefit in subjective evaluation only (65 v 50 points, Mann-Whitney test, cft, p = 0.02) for those with a below-knee walking plaster. There were no significant differences between the groups in the loaded dorsal range of movement (25° v 23°, Mann-Whitney test, cft, p = 0.16) or in the overall clinical result. Both treatments were considered to be satisfactory and their choice depends on the ability to mobilise non-weight-bearing, wound healing, the type of work and personal preference.

We have used total hip replacement combined with cemented intramedullary nailing to treat a selected group of nine patients with pathological fractures of the proximal femur and impending fractures of the shaft due to metastases. One patient died from cardiopulmonary failure on the third postoperative day, but the others were able to walk within the first week after operation.

Complications included one recurrent dislocation of the THR and one fracture of an osteolytic lesion of the femoral shaft during nail insertion. Both were managed successfully.

The hybrid osteosynthesis which we describe is an alternative to the use of tumour or long-stem prostheses; it has the advantage of preserving bone stock and muscle attachments.

We performed a prospective, randomised trial on 120 patients with redisplaced fractures of the distal radius comparing four methods of treatment. The four treatment groups, each containing 30 patients, were remanipulation and plaster, open reduction and bone grafting, and closed external fixation with and without mobilisation of the wrist at three weeks.

The radiological results showed improvement in angulation of the distal radius for the open reduction and bone grafting group. Functional results at six weeks, three and six months and at one year, however, showed no difference between any of the four groups. The main influence on final outcome was carpal malalignment which had a statistically significant negative effect on function.

We have reviewed 30 patients who had been treated conservatively for acromioclavicular dislocation between 1979 and 1982 at an average of 12.5 years after the injury. All except one had a good outcome as did five others contacted by telephone. In all patients reviewed the acromioclavicular joint remained subluxed or dislocated.

With conservative treatment a good long-term outcome can be expected without restoration of the anatomical configuration of the joint.

We reviewed 23 patients who had had 25 Darrach procedures for traumatic or post-traumatic disorders of the wrist at a mean follow-up of 75.5 months (36 to 121). The mean age at the time of operation was 61.1 years (34 to 82). All patients were reviewed in person. Assessment included a history, a questionnaire on patient satisfaction and a detailed physical examination. Standardised radiographs of both wrists were taken with the patient’s hands in a resting position and during maximal grip.

Convergence of the distal ulnar stump towards the distal radius during maximal grip (dynamic radio-ulnar convergence) was seen in 14 wrists including five with actual contact (dynamic radio-ulnar impingement), but this produced symptoms in only two cases. The presence of dynamic radio-ulnar convergence did not correlate with grip strength, pinch strength, range of movement or wrist score, but was associated with increased length of excision of the distal ulna. Nineteen of the 23 patients were satisfied with the procedure.

Dynamic radio-ulnar convergence is common after the Darrach procedure, but is rarely symptomatic; resection of the distal ulna remains a reliable procedure in the older patient with pain and loss of movement. Excision of the lower end of the ulna should be restricted to the least required to restore full rotation.

Only a few cases of palmar carpal subluxation associated with an ulnovolar fragment from the distal radius have been reported previously. We report a case which was treated operatively six months after the injury.

We report a prospective, stratified study of 60 PCA-cups and 60 RM-polyethylene cups which have been followed for a median time of 90 months, with annual radiography.

The radiological migration of cups was measured by the computer-assisted EBRA method. A number of threshold migration rates from 1 mm in the first year to 1 mm in five years have been assessed and related to clinically determined revision rates. A total of 28 cups showed a total migration of 1 mm or more within the first two years; 13 of these cups have required revision and been exchanged.

The survival curves of cups which had previously shown early migration were considerably different from those without early migration. For cups with a migration of less than 1 mm within the first two years the mean survival at 96 months was 0.96 ± 0.02; for migrating cups, it was 0.63 ± 0.11 (log-rank test, p = 0.0001; chi-square value = 39.4).

Early migration is a good predictor for late loosening of hip sockets.

Postoperative deep-vein thrombosis (DVT) is believed to be rare in Asians. We studied 88 consecutive patients in Malaysia who had operations for fracture of the proximal femur or for total hip or knee replacement. No patient had prophylaxis against DVT; bilateral ascending venography was performed between six and ten days after operation.

A total of 55 patients (62.5%) showed venographic evidence of DVT. The prevalence was greatest after total knee replacement (76.5%), less after total hip replacement (64.3%) and smallest in the fracture group (50%). One patient developed symptomatic pulmonary embolism.

In contrast to other reports from Asia, we found an incidence of postoperative DVT which is similar to that reported in Western populations. This suggests that the present practice of withholding routine prophylaxis against thromboembolism in Asian patients undergoing high-risk orthopaedic procedures should be reconsidered.

Any operation induces an elevation in the level of serum C-reactive protein (CRP). After hip and knee arthroplasty the maximal values are seen on the second and third postoperative days, after which the CRP decreases rapidly. There is no difference between patients with cemented or uncemented prostheses. Major postoperative complications may cause a further increase in CRP levels at one and two weeks.

We investigated the effect of a fibrinolytic inhibitor, tranexamic acid, on blood loss and blood transfusion in knee arthroplasty by a randomised, double-blind study of 86 patients. A dose of 10 mg/kg body-weight of either tranexamic acid or placebo was given intravenously shortly before the release of the tourniquet, and repeated three hours later. The mean total blood loss was 730 ± 280 ml in the tranexamic acid group as against 1410 ± 480 ml in the placebo group (p < 0.001).

Both the number of patients receiving blood transfusion and the number of blood units transfused were reduced to one-third in the treated group, and mean postoperative Hb concentrations were significantly higher after prophylaxis. The number of thromboembolic complications was the same in both groups. Tranexamic acid should be given prophylactically in order to be effective.

The Kinematic Stabilizer is a posterior-cruciate-substituting design of total knee replacement. We have reviewed 109 primary total knee replacements in 95 patients at a mean follow-up time of 12.7 years (10 to 14). We used survival analysis with failure defined as revision of the implant. This gave a cumulative survival rate of 95% (95% CI± 5%) at ten years and 87% (± 10%) at 13 years.

These results from an independent centre confirm the value of an established design of cemented total knee replacement and question the wisdom of the introduction of modifications and new designs without properly controlled trials.

The operative treatment of lesions of the anterior cruciate ligament (ACL) in athletes has been widely advocated and performed. We have investigated the outcome of non-operative management in a lower-demand, general population. We reviewed a consecutive group of 228 patients, which excluded professional and high-level athletes, for two to 12 years after an ACL lesion had been diagnosed by arthroscopy.

There was a low incidence of secondary ACL and meniscal surgery, 5.4% and 3.5% respectively, and all these procedures were performed during the first three years after the ACL injury.

We studied a subgroup of 109 patients with follow-up of at least five years (mean 8.5 years) and evaluated them using the IKDC score. The general outcome was reasonably satisfactory, with 23% in grade A, 50% in grade B, 21% in grade C and only 6.4% in grade D. We found no statistically significant prognostic effect within this group as regards age, activity levels, or the incidence of associated lesions.

The radiological and MRI appearances of 24 knees with patellar tendonitis resistant to conservative therapy were analysed to identify the characteristic MRI appearance and to determine if the patellar morphology was abnormal. A significant thickening of the tendon was found in all cases; this was a more reliable diagnostic feature than a high signal within the superior posterior and central aspect of the tendon at its proximal attachment

The site of the lesion shown by MRI is more compatible with impingement of the inferior pole of the patella against the patellar tendon than a stress overload of the tendon. There were no significant differences in the length of the patella, inferior pole or length of the articular surface when the patellar morphology was compared with that of a matched control group.

We present a patient with an arteriovenous fistula of the peroneal artery acquired after a left dome tibial osteotomy with midshaft fibular osteotomy. He had subsequently had a total knee replacement on that side. The arteriovenous malformation was only diagnosed when he represented with symptoms and signs of venous hypertension with sterile recurrent haemarthroses in the left knee. Percutaneous obliteration of the fistula, by a combination of coil embolisation and balloon occlusion, cured the symptoms.

We assessed 46 Syme’s amputees attending our prosthetic clinics in terms of the clinical and radiological condition of their stumps, their level of function and problems with the prosthesis.

Twenty-five were compared with a matching group of 25 transtibial amputees in regard to activity, function and prosthetic behaviour. Function was similar in the two groups, but Syme’s amputees had a higher incidence of prosthetic failure. Overall, Syme’s amputees were pleased with their prostheses and their function. Childhood amputations were associated with fewer long-term problems in terms of function and stump problems

Syme’s amputation is indicated for congenital foot deformities, fibular hemimelia and severe injury to the foot as long as the heel pad remains viable.

Surgical exposure of the ankle is usually obtained by an anterior approach, especially for replacement arthroplasty. The transfibular approach has been popular for arthrodesis.

We describe a new posterior approach to the ankle and posterior subtalar joint based on an extra-articular vertical calcaneal osteotomy behind the subtalar joint. The posterior flap so formed is hinged medially and offers wide exposure of the back of the ankle and posterior subtalar joint. This hinge allows safe and stable reduction of the osteotomised calcaneum, and the plane of dissection follows an ‘internervous plane’ behind the fibula.

We have had good results after using this incision in 12 patients with osteoarthritis or rheumatoid arthritis and there have been no difficulties with wound healing.

We have studied retrospectively 37 hips in 36 children at an average of 91 months after simultaneous open reduction and Salter innominate osteotomy for developmental hip dysplasia. At the latest review 97.3% were clinically and 83.8% radiologically good or excellent. In three hips (8%) there were signs of avascular necrosis, but only one had been symptomatic. There were no cases of recurrent posterior displacement.

We report a postal survey of 59 families of children with osteogenesis imperfecta. From the 51 replies we collected data on developmental milestones and walking ability and related them to the Sillence and the Shapiro classifications of osteogenesis imperfecta. Twenty-four of the patients had been treated by intramedullary rodding.

Both classifications helped to predict eventual walking ability. We found that independent sitting by the age of ten months was a predictor for the use of walking as the main means of mobility with 76% attaining this. Of the patients who did not achieve sitting by ten months, walking became the main means of mobility in only 18%. The developmental pattern of mobility was similar in the rodded and non-rodded patients.

We examined prospectively 4719 newborn infants to determine the congenital incidence of trigger thumb. No cases were found.

Fifteen other children aged from 15 to 51 months had surgery for this condition. The anomaly had not been seen at birth and all thumbs presented with a flexion contracture without triggering. The condition is usually seen after birth as a flexion contracture of the interphalangeal joint. The term ‘congenital’ is a misnomer because patients acquire the deformity after birth. The term ‘trigger’ is inaccurate as most thumbs show a fixed-flexion contracture without triggering.

We suggest that rather than ‘congenital trigger thumb’ a more appropriate description of this disorder is ‘acquired thumb flexion contracture in children’. If the contracture persists after one year of age, treatment by dividing the A-1 pulley is simple and effective.

We studied 45 children who presented with an inversion injury of the ankle. The clinical signs suggested injury to the distal growth plate of the fibula, but the plain radiographs appeared normal. Ultrasound examination of the joint in 40 patients showed a subperiosteal haematoma consistent with a growth-plate injury in 23 (57.5%). Children who had been treated with a tubular bandage and crutches by random selection had a mean time to return of normal activity of 14.22 days compared with 21.60 days for those treated with a plaster-of-Paris cast (t = 3.60, p = 0.0032; d = 7.38, 95% CI 3.0 to 11.8).

We conclude that children with inversion ankle injuries who have clinical signs of injury to the distal fibular growth plate but a normal radiological appearance, should be treated with a tubular bandage and crutches.

We report a 45-year follow-up of a patient with Engelmann’s disease previously described in 1950, showing progression of the disease with unique involvement of the femoral capital epiphyses. The case is compared with others to add some information about the later stages of a disease which is not fully understood

A kindred of seven affected individuals in three generations is described with autosomal dominant inheritance of bilateral five-fingered hands, pedal polydactyly with syndactyly and agenesis of the tibia and of the lower end of the radius.