The Gamma nail was designed to treat unstable intertrochanteric and subtrochanteric fractures. The device was developed after cadaver studies and has been used clinically since February 1985 in a total of 421 patients. The results in 123 patients treated by the third version of this design are reported. The Gamma nail transmits weight closer to the calcar than does the dynamic hip screw and it has greater mechanical strength. A semi-closed operative technique is used, with an average duration of operation of 35 minutes and little blood loss. Distal locking screws can be used to maintain rotational stability, and can be inserted without the use of an image intensifier. Results showed satisfactory fracture union with little loss of position, even in comminuted fractures. Operative complications were few, but included fractures of the base of the greater trochanter. The most important postoperative complication, seen in one case, was fracture of the shaft of the femur at the distal end of the nail, but this healed well after re-nailing.

The Gamma nail was introduced for the treatment of peritrochanteric fractures with the theoretical advantage of a load-sharing femoral component which could be implanted by a closed procedure. We report a randomised prospective study of 186 fractures treated by either the Gamma nail or a dynamic hip screw. Gamma nails were implanted with significantly shorter screening times, smaller incisions, and less intraoperative bleeding. The Gamma nail group had a shorter convalescence and earlier full weight-bearing, but there was no significant difference in mortality within six months, postoperative mobility, or hip function at review. More intra-operative complications were recorded in the Gamma nail group, mainly due to the mismatching of the femoral component of the nail to the small femurs of Chinese people. Use of a smaller modified nail reduced these complications. We conclude that with careful surgical technique and the modified femoral component, the Gamma nail is an advance in the treatment of peritrochanteric fractures.

We examined the effect of the Gamma nail on strain distribution in the proximal femur, using ten cadaver femora instrumented with six unidirectional strain gauges along the medial and lateral cortices. The femora were loaded to 1800 N and strains were determined with or without distal interlocking screws before and after experimentally created two-part and four-part fractures. Motion of the sliding screw and the nail was also determined. Strain patterns and screw motion were compared with previously obtained values for a sliding hip screw device (SHS). The Gamma nail was shown to transmit decreasing load to the calcar with decreasing fracture stability, such that virtually no strain on the bone was seen in four-part fractures with the posteromedial fragment removed; increasing compression was noted, however, at the proximal lateral cortex. Conversely, the SHS showed increased calcar compression with decreasing fracture stability. The insertion of distal interlocking screws did not change the pattern of proximal femoral strain. The Gamma nail imparts non-physiological strains to the proximal femur, probably because of its inherent stiffness. These strains may alter bone remodelling and interfere with healing. Distal interlocking screws may not be necessary for stable intertrochanteric fractures.

We treated 24 patients with nonunion of tibial shaft fractures by locked intramedullary nailing, 18 by open and six by closed techniques. Union was achieved in 22 patients, failing only in two patients with active infection. Locked nailing prevented recurrence of deformity and allowed the patients to mobilise without external support. Supplementary bone grafting was essential only for major defects.

In ipsilateral mid-clavicular and scapular-neck fractures, the mechanical stability of the suspensory structures is disrupted and muscle forces and the weight of the arm pull the glenoid fragment distally and anteromedially. To prevent late deformity we recommend internal fixation of the fractured clavicle by a plate and screws. We treated seven patients with this unusual injury; all achieved an excellent functional result without deformity.

We describe three patients in whom the tibial nerve was used, in mistake for the plantaris tendon, to repair a ruptured calcaneal tendon. The tendon repair was successful in all cases, but despite attempted reconstruction of the nerve, no patient had any motor recovery although two regained some protective sensation.

We reviewed retrospectively 25 hip arthroplasties in 25 patients with sickle-cell haemoglobinopathy and osteonecrosis. The mean age of the ten women and 15 men at the onset of hip symptoms was 25 years, and at surgery 30 years (16 to 45); 66% had either SS or S-thal disease, 20% sickle-cell trait, and the remainder SC disease. The mean follow-up was 8.6 years (two to 18). Fourteen (40%) of the arthroplasties had been revised at a mean of 7.5 years after the primary procedure and nine other hips were either radiographically and/or symptomatically loose. The overall complication rate was 49% and the infection rate 20%. The risk-to-benefit ratio of hip arthroplasty in sickle-cell haemoglobinopathy is high.

The osseo-integration of an uncemented acetabular component depends on its initial stability. This is usually provided by under-reaming of the acetabulum. We have assessed the fixation of 52 mm porous-coated hemispherical prostheses inserted into cadaveric acetabula under-reamed by 1, 2, 3 and 4 mm. We tested the torsional stability of fixation, after preloading with 686 N in compression, by measuring the torque required to produce 1 degree and 2 degrees of rotation. Under-reaming by 2 mm and 3 mm gave significantly better fixation than 1 mm (p less than 0.01, p less than 0.02). Insertion after under-reaming of 4 mm caused some fractures. To obtain maximum interference fit and optimal implant stability, we recommend the use of an implant 2 mm or 3 mm larger than the last reamer.

Long posterior wall (LPW) Charnley acetabular implants are widely used as it is believed that the LPW helps to prevent dislocation. This has, however, not been proven statistically. In a preliminary study of these implants removed at revision marked erosion of the LPW was frequently seen, indicating that repetitive impingement may occur. The influence of the long posterior wall was therefore investigated mathematically. LPW and standard sockets were found to be equally likely to dislocate provided that the standard socket was anteverted 5 degrees more than the LPW socket. With simulated external rotation, LPW sockets impinge 30% earlier than standard sockets. When impingement occurs a torque is applied to the components, which increases the shear stresses at the cement-bone interface. The torques, although not large enough to dislodge the socket immediately, are repetitive and so may contribute to loosening. The LPW socket can generate twice as much torque as the standard socket and therefore is more likely to loosen.

Reports of differing failure rates of total hip prostheses made of various metals prompted us to measure the size of metallic and polyethylene particulate debris around failed cemented arthroplasties. We used an isolation method, in which metallic debris was extracted from the tissues, and a non-isolation method of routine preparation for light and electron microscopy. Specimens were taken from 30 cases in which the femoral component was of titanium alloy (10), cobalt-chrome alloy (10), or stainless steel (10). The mean size of metallic particles with the isolation method was 0.8 to 1.0 microns by 1.5 to 1.8 microns. The non-isolation method gave a significantly smaller mean size of 0.3 to 0.4 microns by 0.6 to 0.7 microns. For each technique the particle sizes of the three metals were similar. The mean size of polyethylene particles was 2 to 4 microns by 8 to 13 microns. They were larger in tissue retrieved from failed titanium-alloy implants than from cobalt-chrome and stainless-steel implants. Our results suggest that factors other than the size of the metal particles, such as the constituents of the alloy, and the amount and speed of generation of debris, may be more important in the failure of hip replacements.

To assess the effect of improved methods of femoral cementing on the loosening rates in young patients, we reviewed 50 'second-generation' cemented hip arthroplasties in 44 patients aged 50 years or less. The femoral stems were all collared and rectangular in cross-section with rounded corners. The cement was delivered by a gun into a medullary canal occluded distally with a cement plug. A clinical and radiographic review was undertaken at an average of 12 years (10 to 14.8) and no patient was lost to follow-up. No femoral component was revised for aseptic loosening, and only one stem was definitely loose by radiographic criteria. By contrast, 11 patients had undergone revision for symptomatic aseptic loosening of the acetabular component and 11 more had radiographic signs of acetabular loosening.

We describe a case in which chronic oedema of a leg was due to pressure on the external iliac vein from an intrapelvic rheumatoid cyst. Ultrasound and CT scanning gave the clues to diagnosis.

We reviewed 32 deep-frozen irradiated allografts used for the reconstruction of bone defects in 20 knees. They were subdivided into bulk grafts, cortical strut grafts, and morsellised bone. The average follow-up was 4.2 years (2 to 7.2). Radiographs showed union of the allograft to the host in all cases. Two allografts later fractured and three knees required further surgery because of infection. The allografts effectively filled large bone defects around the knee, lessening the need for custom-made and constrained prostheses.

We report the contamination rate in the Cambridge bone bank of 35 consecutive allograft specimens, all harvested in a clean-air environment, using a strict aseptic technique and antibiotic cover. Five of 27 femoral heads taken from living donors and three of eight massive allografts taken from cadavers were found to be contaminated. The contaminated femoral heads were discarded. All massive allografts were rendered sterile by gamma-irradiation. It is important to exclude bacteriological contamination of harvested and banked bone.

We discuss the role of primary knee arthroplasty in supracondylar and intercondylar fractures of the femur in elderly patients with reference to 13 cases. This method of treatment is shown to be effective and to have good results. It is recommended for all type C and some type A supracondylar fractures in old people.

We studied arthroscopically the meniscal pathology in 100 patients with functional instability of the knee from isolated rupture of the anterior cruciate ligament at an average time of three years after injury. Meniscal tears were observed in 86 patients and multiple lesions of both menisci were common. An incomplete longitudinal cleavage, visible on both surfaces of the posterior horn, was seen in more than half the knees and seemed to indicate progressive meniscal deterioration. Clinical examination was unreliable and we suggest that arthroscopic assessment is necessary for accurate diagnosis and staging.

We performed bilateral femoral shortening operations on 15 skeletally mature patients (11 women and four men). Their mean height pre-operatively was 193.5 cm and they were shortened by 5 to 9 cm. We used a subtrochanteric Z-osteotomy with an AO condylar plate in 11 patients, and mid-diaphyseal osteotomy with an intramedullary locking nail in four. After an average follow-up of 8.1 years, isokinetic muscle testing showed that muscle strength was reduced bilaterally in five patients. The strength ratio between hamstrings and quadriceps muscles was normal in all those treated by subtrochanteric shortening; in those shortened at the mid-shaft the quadriceps was relatively weaker. The result was rated as excellent by 11 patients, very good by three, and good by one.

Degenerative arthritis of the elbow is a poorly recognised condition, usually seen in a middle-aged man with an occupation or activity which involves the repetitive use of his dominant arm. Flexion contracture and pain at terminal extension are common presenting features. Fifteen patients were reviewed at a mean of 33 months after debridement by ulnohumeral arthroplasty. Fourteen had good relief of pain, elbow extension had improved by an average of 11 degrees and elbow flexion by 10 degrees. On an objective scale 12 of the 15 patients had good or excellent results and 13 (87%) felt that they were improved by the operation.

We have studied the reported clinical assessment of the presence and extent of a rotator cuff tear in 42 patients presenting to a special shoulder clinic. This pre-operative diagnosis was compared with the findings at operation. The clinical tests had a sensitivity of 91% and a specificity of 75%. It is important to exploit clinical examination before resorting to costly and sometimes harmful special investigations.

External fixation of the first metacarpal was used in Rolando's fracture to counter the forces that cause shortening and articular incongruity. Satisfactory reduction was achieved and maintained in five patients.

Closed tenotomy was used to treat triggering of the fingers and thumb in 54 patients. In 56 digits the method was successful; in seven it was a simple matter to proceed to open tenotomy. With experience, the closed procedure can be completed within minutes without risk of damaging the digital nerves.

The action of fast bowling in the game of cricket is known to cause injuries to the lumbar spine. We studied a group of 16- to 18-year-old fast bowlers, selected for special training in Western Australia. All 24 had MR scans of the spine, 22 had radiographs and CT scans; in 20 the bowling technique was analysed biomechanically. There was a high incidence of back pain and this was always associated with a radiological abnormality. Pars interarticularis defects were diagnosed in 54% and intervertebral disc degeneration in 63%. Bowling actions which involved counter-rotation were associated with a higher incidence of both injuries.

Between 1979 and 1989, we treated 22 patients with symptomatic lumbar spondylolysis which had not responded to conservative treatment by a modified Scott wiring technique to give direct repair of the lytic defects with stabilisation. The patients' mean age at the time of operation was 15 years; the mean follow-up period was four years. All 19 patients under 25 years old had satisfactory results. Two of the three patients over 25 years old had poor results. The age of the patient at surgery seems to be an important determinant of outcome. Radiologically confirmed fusion is of secondary importance. The presence of a grade I spondylolisthesis did not prejudice the result. We recommend the Scott wiring technique to stabilise the direct repair of a lumbar spondylolysis.

We attempted to correlate the findings of MRI and discography in patients with low back pain, examining 108 lumbar intervertebral discs in 33 consecutive patients. MRI results were assessed from the intensity and shape of the signal obtained from the central part of the disc. Discography was classified according to the pattern of contrast material, the pressure accepted and the pain reproduced. All discs which were abnormal on MRI had altered patterns on discography, but 18 of the 60 discs with normal MRI had abnormal discograms. Of 39 asymptomatic discs, 33 had normal MRI signals and 24 had normal discograms. None of the 15 discs showing severe degeneration on MRI sustained high levels of intradiscal pressure, but only six of the 60 discs giving normal MRI had low pressure. With current techniques, discography is more accurate than MRI for the detection of annular pathology: a normal MRI does not exclude significant changes in the peripheral structure of the intervertebral disc which can produce low back pain.

Eight children with missed Monteggia fracture-dislocations are described. Seven had reconstructive surgery which included resection of scar tissue from the radiohumeral joint, proximal ulnar osteotomy, reduction of the radial head and reconstruction of the annular ligament. One had excision of the radial head. Excellent results were obtained in patients under ten years of age, up to four years after the initial injury.

The exceptionally high prevalence of diastrophic dysplasia in Finland has enabled us to analyse the foot deformities of 102 patients at their first orthopaedic evaluation and classify 204 feet into five categories. The most common finding (43%) was a foot with tarsal valgus deformity and metatarsus adductus; 37% showed either equinovarus adductus (29%) or equinus (8%) deformities. At the first examination 13% showed metatarsus adductus deformity alone, and 7% were clinically normal. The expression 'club foot', generally used for the foot deformity in diastrophic dysplasia is a misnomer. There is a wide spectrum of deformities, some of them specific for the condition.

We reviewed the long-term results of the Dillwyn Evans procedure for club foot in 60 feet of 45 patients with an average age of 29 years, using four different scoring systems. The results at 12 to 38 years were compared with those of an earlier study of the same group of patients. Function was satisfactory in 68% of feet; 90% of the patients were able to perform all desired activities. Mild residual deformity was compatible with satisfactory function, and poor function was related to ankle and subtalar stiffness. Our results suggest that this procedure has a low rate of deterioration and degenerative change with time.

Benign paroxysmal torticollis is a self-limiting condition occurring during infancy. It resolves by the age of two to three years. Periodic episodes of torticollis may randomly alternate from side to side and be associated with other symptoms. The aetiology is unknown and no treatment is effective. It is relatively uncommon, and has not been previously reported in the orthopaedic literature, although initial referral may well be to an orthopaedic surgeon. We report four cases, and review the literature.

In 33 dogs we implanted femoral stems made either of carbon composite, some coated with hydroxyapatite, or of titanium alloy with a porous coating. Osseointegration was greater in the hydroxyapatite-coated than in the un-coated stems (p less than 0.001). Push-out tests, at an average of 7.2 months after implantation, showed a six-fold increase in interface shear strength and a twelve-fold increase in shear stiffness in the hydroxyapatite-coated group compared with noncoated implants. The highest shear-strength values were found in the porous-coated titanium alloy stems, around which there was also the most resorptive bone remodelling.

Experimental injuries of cartilage and bone were produced by applying shear force to the articular surfaces of the lateral femoral condyles of six-month-old pigs under various loading conditions. The lesions were divided into two groups, 'open' or 'closed', depending on the presence of a crack on the articular surface. Each was further divided into four types according to the depth of penetrating injury: (1) splitting of uncalcified cartilage; (2) splitting at the subchondral plate; (3) subchondral fracture; and (4) intra-articular fracture. When shear force was applied at high speed but with low energy, the articular cartilage surface was the first to crack. At low speed and low energy, splits occurred in the deeper layers first. As the energy increased, both loading conditions eventually resulted in similar open lesions. Experimentally produced shear injuries are useful models for clinical osteochondral fracture, osteochondritis dissecans, and chondromalacia patellae.

We have investigated the changes in the interposed capsule after a Chiari pelvic osteotomy, in an experimental study on dysplastic hips in 20 adolescent rabbits. Radiographic, macroscopic and microscopic observations were made up to 12 months after operation. The new acetabular roof had incorporated the interposed capsule and remodelled completely by six months. By 12 months there was a new, stable hip with continuity between the capsule and the original acetabular cartilage. Histologically, the capsule underwent metaplastic change to fibrocartilaginous tissue after six months, with some hyaline-like cartilage near the joint surface. These changes in the interposed capsule play an important role in the formation of a new joint after a Chiari pelvic osteotomy.