Aims

Computer-based applications are increasingly being used by orthopaedic surgeons in their clinical practice. With the integration of technology in surgery, augmented reality (AR) may become an important tool for surgeons in the future. By superimposing a digital image on a user’s view of the physical world, this technology shows great promise in orthopaedics. The aim of this review is to investigate the current and potential uses of AR in orthopaedics.

We evaluated the accuracy of six clinical tests for posterior instability in 24 knees with acute surgically-proven posterior cruciate ligament injuries and intact anterior cruciate ligaments. We also performed stress radiography under anaesthesia. The gravity sign and the posterior drawer test in near extension and its passive reduction were diagnostic in 20 of the 24 knees, and the active reduction of posterior subluxation was diagnostic in 18. The reversed pivot shift sign helped to diagnose severe posterior and posterolateral subluxations, but the external rotation recurvatum test was negative in all 24 knees. Stress radiography in near extension revealed a highly significant increase in posterior tibial subluxation in the injured knees

Our aims were to describe the distribution of α-smooth muscle actin (SMA)-containing cells in Dupuytren’s tissue in vivo and to determine the effects of selected agents in regulating the expression of SMA in Dupuytren’s cells in vitro. In selected hypercellular zones of Dupuytren’s nodules up to 40% of the cells contained SMA, as shown by immunohistochemistry. A lower percentage (20%) of SMA-containing cells was found in regions of lower cellularity. A notable finding was that treatment in vitro of Dupuytren’s cells with platelet-derived growth factor significantly reduced the content of SMA. Cells from the same patients showed a significant increase in expression of SMA in response to treatment with transforming growth factor, which confirmed recent findings. In addition, interferon-γ, which has been previously used as a treatment for Dupuytren’s disease in a clinical study, had no reproducible effect on the expression of this actin isoform. Our findings are of significance for the conservative management of contractures

In a prospective randomised clinical study acetabular components were implanted either freehand (n = 30) or using CT-based (n = 30) or imageless navigation (n = 30). The position of the component was determined post-operatively on CT scans of the pelvis. Following conventional freehand placement of the acetabular component, only 14 of the 30 were within the safe zone as defined by Lewinnek et al (40° inclination . sd. 10°; 15° anteversion . sd. 10°). After computer-assisted navigation 25 of 30 acetabular components (CT-based) and 28 of 30 components (imageless) were positioned within this limit (overall p < 0.001). No significant differences were observed between CT-based and imageless navigation (p = 0.23); both showed a significant reduction in variation of the position of the acetabular component compared with conventional freehand arthroplasty (p < 0.001). The duration of the operation was increased by eight minutes with imageless and by 17 minutes with CT-based navigation. Imageless navigation proved as reliable as that using CT in positioning the acetabular component

We carried out a randomised, prospective, multicentre clinical trial of the treatment of Colles’ fractures. A total of 339 patients was placed into two groups, those with minimally displaced fractures not requiring manipulation (151 patients) and those with displaced fractures which needed manipulation (188 patients). Treatment was by either a conventional Colles’ plaster cast (a control group) or with a prefabricated functional brace (the Aberdeen Colles’ fracture brace). Similar results were obtained in both groups with regard to the reduction and to pain scores but the brace provided better grip strength in the early stages of treatment. This was statistically significant after five weeks for both manipulated and non-manipulated fractures. At the tenth day the results were statistically significant only in manipulated fractures. There was no significant difference in the functional outcome between the two treatment groups. However, younger patients and those with less initial displacement had better functional results

Electromyographic and clinical studies were performed on patients undergoing total hip replacement by the modified direct lateral (29 hips), the direct lateral (29 hips) and the posterior approaches (21 hips). Assessments were made three months after operation. The Trendelenburg test was positive (Grade II) in eight cases operated upon by the direct lateral route, but in only one of each of the other two groups. Denervation occurred in only five of the 28 hips with abductor weakness without statistical difference between the groups. In the modified direct lateral group, radiological evidence of union of the trochanteric sliver was associated with significantly better abductor function than in those with malunion or non-union

Our objectives were to establish the envelope of passive movement and to demonstrate the kinematic behaviour of the knee during standard clinical tests before and after reconstruction of the anterior cruciate ligament (ACL). An electromagnetic device was used to measure movement of the joint during surgery. Reconstruction of the ACL significantly reduced the overall envelope of tibial rotation (10° to 90° flexion), moved this envelope into external rotation from 0° to 20° flexion, and reduced the anterior position of the tibial plateau (5° to 30° flexion) (p < 0.05 for all). During the pivot-shift test in early flexion there was progressive anterior tibial subluxation with internal rotation. These subluxations reversed suddenly around a mean position of 36 ± 9° of flexion of the knee and consisted of an external tibial rotation of 13 ± 8° combined with a posterior tibial translation of 12 ± 8 mm. This abnormal movement was abolished after reconstruction of the ACL

The proximal femoral nail (PFN) is a recently introduced intramedullary system, designed to improve treatment of unstable trochanteric fractures of the hip. In a multicentre prospective clinical study, the intra-operative use, complications and outcome of treatment using the PFN (n = 211) were compared with those using the gamma nail (GN) (n = 213). The intra-operative blood loss was lower with the PFN (220 ml v 287 ml, p = 0.001). Post-operatively, more lateral protrusion of the hip screws of the PFN (7.6%) was documented, compared with the gamma nail (1.6%, p = 0.02). Most local complications were related to suboptimal reduction of the fracture and/or positioning of the implant. Functional outcome and consolidation were equal for both implants. Generally, the results of treatment of unstable trochanteric fractures were comparable for the PFN and GN. The pitfalls and complications were similar, and mainly surgeon- or fracture-related, rather than implant-related

The integrity of the periosteum and the interosseous membrane determine the stability of fractures of the distal ulna; this is indicated by the initial displacement. In fractures displaced by less than 50% the periosteum and interosseous membranes are largely intact; these fractures are stable and require only below-elbow immobilisation for protection and relief of pain. In fractures displaced by more than 50% the membranes are disrupted; these fractures are unstable and require above-elbow immobilisation for stability. As most fractures are displaced by less than 50%, immobilisation of the elbow, which significantly increases morbidity, is usually unnecessary. I report the results of a cadaveric study on the pathomechanics of fractures of the distal ulna, and of a prospective clinical trial in which the type of cast used for immobilisation was determined by the stability of the fracture

We sought to quantify agreement by different assessors of the AO classification for distal fractures of the radius. Thirty radiographs of acute distal radial fractures were evaluated by 36 assessors of varying clinical experience. Our findings suggest that AO ‘type’ and the presence or absence of articular displacement are measured with high consistency when classification of distal radial fractures is undertaken by experienced observers. Assessors at all experience levels had difficulty agreeing on AO ‘group’ and especially AO ‘subgroup’. To categorise distal radial fractures according to joint displacement and AO type is simple and reproducible. Our study examined only whether distal radial fractures could be consistently classified according to the AO system. Validation of the classification as a predictor of outcome will require a prospective clinical study

In controlled clinical studies of adult diabetics a 42% incidence of signs of Dupuytren's disease was found. The incidence was highest in the older patients with a longer history of diabetes, but was not related to the severity of the diabetes. The features of Dupuytren's disease in the diabetics has a distinctive pattern, being more severe in men than women and, compared with controls, having a radial shift towards the middle finger. The disease was mild and of benign prognosis, rarely needing operation. In a further study, 13% of patients with Dupuytren's disease were found to have a raised blood glucose level. The question is posed as to whether the biochemical disturbance causes the Dupuytren's disease or whether the pattern of inheritance predisposes to both Dupuytren's disease and diabetes

A prospective randomised clinical trial was undertaken to compare biodegradable polyglycolic acid pins with standard Kirschner wires used to fix displaced elbow fractures in children. Twenty-four children were enrolled in the trial; 14 had fractures of the lateral condyle of the humerus, eight of the medial epicondyle and two had olecranon fractures. Eleven fractures were fixed with Kirschner wires and 13 with polyglycolic acid pins. Fracture union with full function occurred in all cases within six months. Kirschner wires caused problems including infection in three cases, soft-tissue ossification in one and they required removal under general anaesthesia in nine cases. No such complications occurred with polyglycolic acid pins but one patient in this group developed avascular necrosis and premature fusion of the medial epicondyle

A clinical study has been made of forty-three patients with symptoms arising from degenerative spondylolisthesis of the lumbar spine. Attention is drawn to the lower average level of the iliac crests in these patients, and to the high incidence of osteoarthritis of the hips. Many patients in this series had been referred specifically for operation and fourteen were so treated. The techniques of decompression and of spinal fusion are discussed. It is concluded that patients with back pain predominant are well treated by corsetry, only a minority needing fusion, and that patients with nerve root involvement or with symptoms of spinal stenosis need decompression. The place of spinal fusion is the main problem, but it seems reasonable, firstly, in younger patients with clear evidence of instability and degenerative change at a single level, and secondly, when radical decompression is judged to increase the risk of instability

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

Cancer-induced bone diseases are often associated with increased bone resorption and pathological fractures. In recent years, osteoprotective agents such as bisphosphonates have been studied extensively and have been shown to inhibit cancer-related bone resorption in experimental and clinical studies. The third-generation bisphosphonate, ibandronate (BM 21.0955), is a potent compound for controlling tumour osteolysis and hypercalcaemia in rats bearing Walker 256 carcinosarcoma. We have studied the effect of ibandronate given as an interventional treatment on bone strength and bone loss after the onset of tumour growth in bone. Our results suggest that it is capable of preserving bone quality in rats bearing Walker 256 carcinosarcoma cells. Since other bisphosphonates have produced comparable results in man after their success in the Walker 256 animal models our findings suggest that ibandronate may be a powerful treatment for maintaining skeletal integrity in patients with metastatic bone disease

We compared two cementless femoral components, the 'isoelastic' Butel stem and the more rigid PCA design, in a randomised, prospective study of 56 patients with a mean follow-up of 4 years (2 to 5). Patients were matched in 28 pairs, and one of each pair was treated with each femoral component. The isoelastic stem gave fewer signs of stress shielding radiologically, but both the Harris hip score and the visual analogue pain scale showed significantly inferior results at the two-year and three-year follow-up. The overall failure rates for the femoral components were 43% for the Butel and 11% for the PCA. These results contrast with those of earlier experimental and clinical studies, in which isoelastic properties appeared to be advantageous. This review emphasises the importance of controlled studies before an altered or new design of prosthesis is released on to the market for general use

Discitis after discography is due to bacterial penetration into the intervertebral disc by a contaminated needle and has an incidence of 1% to 4%. We have examined the prophylactic role of cephazolin administered at the time of discography. An experimental study in sheep using radiographic contrast containing Staphylococcus epidermidis showed that either adding the antibiotic to the intradiscal suspension or giving it intravenously 30 minutes before intradiscal inoculation of bacteria prevented any radiographic, macroscopic or histological signs of discitis; all the intervertebral disc cultures were negative. In a prospective clinical study of 127 consecutive patients having lumbar discography, the injected contrast contained cephazolin 1 mg per ml. None of the patients developed clinical or radiographic signs of discitis. We recommend the use of a suitable broad spectrum antibiotic in a single prophylactic dose whenever the intervertebral disc is entered

A control system for a multifunctional hand prosthesis, which requires a minimum of training for the amputee, has been developed. The great advantage of the pattern recognition technique in making it possible to control as many as six prosthetic movements has prompted this study. The development of a complete miniaturised system has allowed a clinical trial on four patients. Two different tests have been employed to evaluate this system: an objective computer test and a test representing activities of daily living (ADL test). The computer test shows that a high rate of correct recognition is obtained immediately after the prosthesis is applied to the amputee. The ADL test shows that forearm rotation, and flexion and extension of the wrist are used in most activities, indicating that few compensatory movements are performed. It is suggested that this control system is feasible and that long periods of training are unnecessary

A multi-centre clinical trial of ICLH (Freeman-Swanson) arthroplasty has been in progress since 1971. In this paper the results up to two years after operation are reported in seventy-one knees displaying at least 30 degrees of fixed flexion, 25 degrees of valgus or 20 degrees of varus, before operation. It has been found that knees displaying 70 degrees of fixed flexion, 70 degrees of valgus, 30 degrees of varus or 50 degrees of valgus/varus instability can be satisfactorily aligned and stabilised with acceptable function. Three knees required revision. The other complications are listed and were unremarkable in nature. These results depend upon the prosthesis and upon the operative technique. The latter avoids damage to healthy bone but does involve the replacement of the tissues in the midline of the knee