Objectives

The primary objective of this study was to compare accuracy in restoring the native centre of hip rotation in patients undergoing conventional manual total hip arthroplasty (THA) versus robotic-arm assisted THA. Secondary objectives were to determine differences between these treatment techniques for THA in achieving the planned combined offset, component inclination, component version, and leg-length correction.

A series of 167 patients with Charnley-type total hip replacements were studied retrospectively to determine the incidence of trochanteric non-union, the degree of postoperative trochanteric displacement, and the relation between these two complications. The power in the hip abductor muscles, measured with a load-cell device, was significantly reduced if the trochanteric fragment had displaced proximally by more than 3 cm; 12% of those studied fell into this group and, as a consequence, had a poorer result. It was concluded that displacement of the trochanter was of greater importance than bony union in determining function in the replaced hip. Because these unwanted problems may compromise an otherwise successful operation, it is suggested tentatively that trochanteric osteotomy should be abandoned except for difficult primary operations or for revision procedures

From 1987 to 1993 we treated 33 patients with 29 phalangeal and seven metacarpal fractures by external fixation using a mini-Hoffmann device. There were 27 open and 25 comminuted fractures. In 12 patients one or more tendons was involved. The mean follow-up was 4.4 years. Complications occurred in ten fractures; two required repositioning of the fixator. All the fractures healed. The functional results after metacarpal fractures were better than those after phalangeal fractures and fractures of the middle phalanx had better recovery than those of the proximal phalanx. Twenty-eight of the 33 patients were satisfied with their result. External fixation proved to be a suitable technique for stabilising unstable, open fractures with severe soft-tissue injuries

Acute swelling of the hand is a common problem after trauma or surgery and is associated with both pain and loss of function. We describe a prospective study of 47 patients in which we assessed the effects of a pneumatic compression device (A-V impulse hand pump) on the swollen hand. The pump reduced swelling by increasing the velocity of venous return as demonstrated by Duplex scanning of the median cubital vein. Continuous use of the pump for 48 hours gave a reduction of 78.6% in swelling of the injured hand compared with the opposite, uninjured side. Even when used intermittently, with the pump on for 12 hours out of 24, a statistically significant effect was seen. There was a subjective reduction in pain and an objective improvement in function of the hand. Use of the pump resulted in a nearly normal hand by the time of discharge from hospital after, on average, 48 hours

We used 11 cadaver elbows and a three-dimensional electromagnetic tracking device to record elbow movements before and after implantation of a 'loose-hinged' elbow prosthesis (modified Coonrad). During simulated active motion there was a maximum of 2.7 degrees (+/- 1.5 degrees) varus/valgus laxity in the cadaver joints. This increased slightly after total elbow arthroplasty to 3.8 degrees (+/- 1.4 degrees). These values are lower than those recorded for the cadaver joints and for the prostheses at the limits of their varus/valgus displacements, indicating that both behave as 'semi-constrained' joints under physiological conditions. They suggest that the muscles absorb some of the forces and moments that in a constrained prosthesis would be transferred to the prosthesis-bone interface

Aims

The aim of this study was to evaluate fretting and corrosion in retrieved oxidized zirconium (OxZr; OXINIUM, Smith & Nephew, Memphis, Tennessee) femoral heads and compare the results with those from a matched cohort of cobalt-chromium (CoCr) femoral heads.

We performed a prospective randomised controlled trial of the A-V Impulse System in 82 patients treated by hemiarthroplasty for subcapital fracture of the femoral neck. The incidence of proximal deep-vein thrombosis as assessed by Doppler ultrasonography was 23% in the control group and 0% in those using the device (p less than 0.01). Calf and thigh circumferences were measured in both groups at seven to ten days after operation. In the treatment group there was a mean relative reduction of postoperative swelling of the thigh by 3.27 cm (p less than 0.001) and of the calf by 1.55 cm (p less than 0.001). The A-V Impulse System appears to be a safe and effective method of reducing the incidence of proximal deep-vein thrombosis, and of postoperative swelling

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

One hundred and seven patients with intertrochanteric fractures of the femur treated with a Richards screw-plate were compared retrospectively with 103 patients treated with a Jewett nail-plate. The mortality and morbidity were similar in the two groups. In patients with comparable fractures, those treated with a Richards device mobilised more quickly and left hospital sooner, and more of them returned to their homes. Failures of stabilisation, both clinically and radiographically, were fewer in this group. The reliability of fixation with a correctly positioned Richards screw-plate could justify the omission of outpatient follow-up in all but a small group of patients with severe unstable fractures or grossly defective bone stock. The higher cost of a Richards implant and the slightly longer operative procedure were outweighed by savings in occupancy of acute and long-stay hospital beds

In a prospective, randomised study we have compared the pertrochanteric external fixator (PF) with the sliding hip screw (SHS) in 100 consecutive patients who were allocated randomly to the two methods of treatment. Details of the patients and the patterns of fracture were similar in both groups. Follow-up was for six months. Use of the PF was associated with significantly less blood loss, a shorter operating time, reduced postoperative pain, shorter hospitalisation (p < 0.001), earlier mobilisation (p < 0.001) and a reduced rate of mechanical complications (p < 0.01). Superficial infection was significantly more common with the PF (p < 0.01), but without long-term adverse consequences. There were no differences in the healing of the fracture, mortality or final functional outcome. Our results indicate that the external fixator is an effective and safe device for treating pertrochanteric fractures and should be considered as a useful alternative to conventional fixation with the sliding hip screw

Osteotomy has been used in the treatment of unstable intertrochanteric hip fractures in an attempt to increase the stability of the fracture fragments. We have assessed this stability in a randomised prospective trial on 100 consecutive patients, all having fixation by an AO dynamic hip screw, comparing anatomical reduction with two types of osteotomy. The groups were similar in terms of age, gender, mental test score, and fracture configuration. There were more failures of fixation in the osteotomy groups, and the operations took longer. We found no clear benefit from osteotomy and therefore recommend anatomical reduction and fixation by a sliding hip screw in most cases. Rarely, a fracture configuration which does not allow load-sharing between the fracture fragments and the device may benefit from an osteotomy or the use of an alternative implant

We analysed the radiographs of 67 patients with displaced malleolar fractures treated by open reduction and internal fixation using absorbable polyglycolide rods. Seventeen patients developed a discharging inflammatory foreign-body reaction, a complication unique to these fixation devices. In 34 patients ovoid osteolytic foci, usually 5 to 10 mm in diameter, appeared within the implant channels six to 12 weeks after the operation. The same lesion occurred in 14 of the 17 patients who developed a foreign-body reaction, whereas only 20 out of the 50 patients with an uneventful course showed osteolytic areas (p less than 0.01). In patients with a foreign-body reaction the osteolytic foci tended to occur in the deepest parts of the implant channels. However, after one year the normal structure of the bone was restored

Of 135 consecutive patients admitted with subtrochanteric fractures of the femur, 104 were studied; half had internal fixation with a Zickel nail and half had a nail-plate device. Fractures treated with a Zickel nail had significantly less blood loss during operation and took less time to walk with full weight-bearing, but the incidence of technical error at operation was higher. Errors included malalignment of the cross-pin, penetration of the femoral cortex and comminution of the greater trochanter. There was mechanical failure within one year of surgery in 17% of the nail-plate series but no implant failures in the Zickel nail group within the same period. The total time spent in hospital was similar in both groups. The Zickel nail provides better fixation for subtrochanteric fractures than a simple nail-plate but, because of technical difficulty, its use should be reserved for surgeons of reasonable experience

A total of 10474 unicompartmental knee arthroplasties was performed for medial osteoarthritis in Sweden between 1986 and 1995. We sought to establish whether the number of operations performed in an orthopaedic unit affected the incidence of revision. Three different implants were analysed: one with a high revision rate, known to have unfavourable mechanical and design properties; a prosthesis which is technically demanding with a known increased rate of revision; and the most commonly used unicompartmental device. Most of the units performed relatively few unicompartmental knee arthroplasties per year and there was an association between the mean number carried out and the risk of later revision. The effect of the mean number of operations per year on the risk of revision varied. The technically demanding implant was most affected, that most commonly used less so, and the outcome of the unfavourable design was not influenced by the number of operations performed. For unicompartmental arthroplasty, the long-term results are related to the number performed by the unit, probably expressing the standards of management in selecting the patients and performing the operation

Aims

It has been suggested that mobile-bearing total knee arthroplasty (TKA) might lead to better outcomes by accommodating some femorotibial rotational mismatch, thereby reducing contact stresses and polyethylene wear. The aim of this study was to determine whether there is a difference between fixed- and mobile-bearing versions of a contemporary TKA with respect to durability, range of movement (ROM) and function, ten years postoperatively.

Moire topography was added to school scoliosis screening in Singapore in 1982. The results from 1342 topographs, assessed in isolation, were used to study the accuracy of the method in predicting the radiographic location and magnitude of scoliotic curves. Accuracy in identifying the site of the curve was 68% in the thoracic spine, 54% in the thoracolumbar spine, and 15% in the lumbar region. There were 12.7% false-positive results and 4.3% false negatives. Of patients with a deviation of one moire fringe, 76.5% had a curve of 15 degrees or less; of those with a deviation of four moire fringes, 69% had a curve greater than 26 degrees. The prediction of the Cobb angle was less accurate when there was a deviation of two or three fringes. It is suggested that moire topography as a screening device should be reserved for use in the second tier of screening, since the forward-bending test is an effective and cheap method for the first tier of a mass school-screening programme

Angular deformities of the distal radius of 15 sheep were induced by asymmetrical epiphysial distraction. Eleven sheep were between 10 and 20 weeks old; four were older than 24 weeks. Gradual distraction on the medial side of the limb caused partial separation of the epiphysis from the metaphysis, resulting in a valgus deformity. The distraction device was removed three to six weeks after insertion. Spontaneous correction of angulation with growth occurred in the younger sheep; but when the induced valgus angle exceeded 20 degrees correction was poor. In two sheep further distraction was applied on the lateral side and this produced complete correction. Premature closure of epiphyses did not occur after distraction and longitudinal growth of the bone remained normal. In the older sheep asymmetrical distraction succeeded in inducing angulation in only one case, and correction was poor

We studied the effect of total knee replacement on venous flow in 110 patients. Resting venous blood flow was measured using straingauge plethysmography before operation, after surgery and after discharge from hospital. There was a significant reduction in mean venous capacitance (p < 0.001) and mean venous outflow (p < 0.004) affecting only the operated leg. Both improved significantly after mobilisation in the early postoperative period, returning to preoperative levels by six days after surgery and before discharge from hospital. Our findings showed that venous stasis may contribute to deep-vein thrombosis only in the first few days after total knee replacement. This would be the most important period for the use of flow-enhancing prophylactic devices. Comparison with changes in blood flow after total hip replacement identified different patterns of altered haemodynamics suggesting that there are different mechanisms of venous stasis and thrombogenesis in hip and knee arthritis and during surgery for these conditions

Objectives

The Precice nail is the latest intramedullary lengthening nail with excellent early outcomes. Implant complications have led to modification of the nail design. The aim of this study was to perform a retrieval study of Precice nails following lower-limb lengthening and to assess macroscopical and microscopical changes to the implants and evaluate differences following design modification, with the aim of identifying potential surgical, implant, and patient risk factors.