Several radiological methods of measuring anteversion of the acetabular component after total hip replacement (THR) have been described. These studies used different definitions and reference planes to compare methods, allowing for misinterpretation of the results. We compared the reliability and accuracy of five current methods using plain radiographs (those of Lewinnek, Widmer, Liaw, Pradhan, and Woo and Morrey) with CT measurements, using the same definition and reference plane. We retrospectively studied the plain radiographs and CT scans in 84 hips of 84 patients who underwent primary THR. Intra- and inter-observer reliability were high for the measurement of inclination and anteversion with all methods on plain radiographs and CT scans. The measurements of inclination on plain radiographs were similar to the measurements using CT (p = 0.043). The mean difference between CT measurements was 0.6° (-5.9° to 6.8°).

Measurements using Widmer’s method were the most similar to those using CT (p = 0.088), with a mean difference between CT measurements of -0.9° (-10.4° to 9.1°), whereas the other four methods differed significantly from those using CT (p < 0.001).

This study has shown that Widmer’s method is the best for evaluating the anteversion of the acetabular component on plain radiographs.

Cite this article: Bone Joint J 2014; 96-B:597–603.

Our purpose was to determine the mechanism which allows the maximum knee flexion in vivo after a posterior-cruciate-ligament (PCL)-retaining total knee arthroplasty.

Using three-dimensional computer-aided design videofluoroscopy of deep squatting in 29 patients, we determined that in 72% of knees, direct impingement of the tibial insert posteriorly against the back of the femur was the factor responsible for blocking further flexion.

In view of this finding we defined a new parameter termed the ‘posterior condylar offset’. In 150 consecutive arthroplasties of the knee, the magnitude of posterior condylar offset was found to correlate with the final range of flexion.

We have sought to clarify whether the traditional Arabic lifestyle prevents restriction of movement in patients with degenerative arthritis of the knee. The range of movement of 68 osteoarthritic knees of Arabic patients was compared with that of 51 healthy knees of Muslim patients and 83 osteoarthritic knees in non-Arabic patients.

The range of flexion of the osteoarthritic knees in the Arabic patients matched that of the healthy control knees, but was significantly better than that of the osteoarthritic knees in the non-Arabic patients. There was also a statistically significant difference between the mean extension deficit of the two groups with osteoarthritis. Exercises may help to prevent restriction of movement in osteoarthritis of the knee.

We used fluoroscopy to study the kinematics of the knee in 47 patients with total knee arthroplasty (TKA) and four control subjects with normal knees while performing a single-leg deep-knee bend. The videos were analysed using still photographs taken at 5 degrees increments of flexion. Femorotibial contact points, patellar ligament rotation, and patellar rotation were calculated from each image. Maximum weight-bearing flexion was determined for each knee. Compared with the control group, posterior-cruciate-retaining TKA did not reproduce normal knee kinematics in any case, but showed a starting point posterior to the tibial midline which translated anteriorly with flexion. The curves from successive knee bends could not be consistently reproduced. Under weight-bearing conditions, the maximum flexion for any PCR TKA was 98 degrees and several patients could not flex beyond 70 degrees.

Biological fixation of cementless femoral implants requires primary stability by optimal fit in the proximal femur. The anatomy of the bone must then be known precisely. We analysed in vitro the accuracy of bone measurements of 32 femurs and compared the dimensions obtained from radiographs and CT scans with the true anatomical dimensions. Standard radiographs gave only a rough approximation of femoral geometry (mean difference: 2.4 +/- 1.4 mm) insufficiently accurate to allow selection of the best fitting prosthesis from a range of sizes and altogether inadequate to design a custom-made prosthesis. CT scans give greater accuracy (mean difference: 0.8 +/- 0.7 mm) in our experimental conditions, but in clinical practice additional sources of error exist.

The hip joint is commonly involved in multiple epiphyseal dysplasia and patients may require total hip replacement before the age of 30 years.

We retrospectively reviewed nine patients (16 hips) from four families. The diagnosis of multiple epiphyseal dysplasia was based on a family history, genetic counselling, clinical features and radiological findings. The mean age at surgery was 32 years (17 to 63), with a mean follow-up of 15.9 years (5.5 to 24).

Of the 16 hips, ten required revision at a mean of 12.5 years (5 to 15) consisting of complete revision of the acetabular component in three hips and isolated exchange of the liner in seven. No femoral component has loosened or required revision during the period of follow-up.

With revision for any reason, the 15-year survival was only 11.4% (95% confidence interval 1.4 to 21.4). However, when considering revision of the acetabular shell in isolation the survival at ten years was 93.7% (95% confidence interval 87.7 to 99.7), reducing to 76.7% (95% confidence interval 87.7 to 98.7) at 15 and 20 years, respectively.

We compared retrospectively consecutive series of patients with cervical dislocation treated at two Australian centres. In Perth, 82 patients were treated by closed reduction and postural nursing. In Adelaide, 85 patients had closed reduction and early surgical stabilisation by interbody fusion. There were 46 bilateral dislocations, 101 unilateral dislocations, and 20 anterior subluxations. On admission 30 patients had complete tetraplegia, 17 incomplete tetraplegia, and 120 had minimal or no neurological loss. Our results indicated that closed manipulation under general anaesthesia is a safe and effective means of reduction in the acute stage. There was a high mortality rate for acute surgery in patients with complete tetraplegia. Early surgical stabilisation by dowel fusion reduced bed and hospital stay in patients with no neurological loss, but seemed to impair neurological recovery in patients with a neurological deficit on admission. Conservative management after reduction of bilateral dislocation or anterior subluxation led to a higher incidence of instability in patients with minimal or no neurological loss; in such cases surgery to stabilise the injured segment is indicated.

Eleven articulated scoliotic spines were examined radiographically and morphometrically. Measurement of the curve on anteroposterior radiographs of the specimens gave a mean Cobb angle of 70 degrees, though true anteroposterior radiographs of the deformity revealed a mean Cobb angle of 99 degrees (41% greater). Lateral radiographs gave the erroneous impression that there was a mean kyphosis of 41 degrees while true lateral projections revealed a mean apical lordosis of 14 degrees. Morphometric measurements confirmed the presence of a lordosis at bony level, the apical vertebral bodies being significantly taller anteriorly (P less than 0.02). There were significant correlations (P less than 0.01) between the true size of the lateral scoliosis, the amount of axial rotation and the size of the apical lordosis. This study illustrates the three-dimensional nature of the deformity in scoliosis and its property of changing in character and magnitude according to the plane of radiographic projection.

Gender-specific total knee replacement has generated much interest recently. We reviewed 1970 Sigma knees implanted in 920 women and 592 men with a mean age of 69.7 years.

At a mean follow-up of 7.3 years (minimum, five years), we found minimal differences in the outcome between genders. At the final follow-up, men had a higher overall Knee Society score and more osteolysis (3.8% vs 1.1%). However, there were no significant differences between men and women in terms of complications or improvements in knee function, pain score or range of movement. The estimated ten-year survivorship was 97% in women and 98% in men (p = 0.96).

We concluded that there was little difference in outcome between the genders treated by a modern unisex design of total knee replacement in this large multicentre study.

A reversed Delta III total shoulder prosthesis was retrieved post-mortem, eight months after implantation. A significant notch was evident at the inferior pole of the scapular neck which extended beyond the inferior fixation screw. This bone loss was associated with a corresponding, erosive defect of the polyethylene cup. Histological examination revealed a chronic foreign-body reaction in the joint capsule. There were, however, no histological signs of loosening of the glenoid base plate and the stability of the prosthetic articulation was only slightly reduced by the eroded rim of the cup.

This study compared component wear rates and pre-revision blood metal ions levels in two groups of failed metal-on-metal hip arthroplasties: hip resurfacing and modular total hip replacement (THR).

There was no significant difference in the median rate of linear wear between the groups for both acetabular (p = 0.4633) and femoral (p = 0.0872) components. There was also no significant difference in the median linear wear rates when failed hip resurfacing and modular THR hips of the same type (ASR and Birmingham hip resurfacing (BHR)) were compared.

Unlike other studies of well-functioning hips, there was no significant difference in pre-revision blood metal ion levels between hip resurfacing and modular THR.

Edge loading was common in both groups, but more common in the resurfacing group (67%) than in the modular group (57%). However, this was not significant (p = 0.3479). We attribute this difference to retention of the neck in resurfacing of the hip, leading to impingement-type edge loading. This was supported by visual evidence of impingement on the femur.

These findings show that failed metal-on-metal hip resurfacing and modular THRs have similar component wear rates and are both associated with raised pre-revision blood levels of metal ions.

In order to identify the risk factors and the incidence of post-operative spinal epidural haematoma, we analysed the records of 14 932 patients undergoing spinal surgery between 1984 and 2002. Of these, 32 (0.2%) required re-operation within one week of the initial procedure and had an International Classification of Diseases (ICD)-9 code for haematoma complicating a procedure (998.12). As controls, we selected those who had undergone a procedure of equal complexity by the same surgeon but who had not developed this complication. Risks identified before operation were older than 60 years of age, the use of pre-operative non-steroidal anti-inflammatories and Rh-positive blood type. Those during the procedure were involvement of more than five operative levels, a haemoglobin < 10 g/dL, and blood loss > 1 L, and after operation an international normalised ratio > 2.0 within the first 48 hours. All these were identified as significant (p < 0.03). Well-controlled anticoagulation and the use of drains were not associated with an increased risk of post-operative spinal epidural haematoma.

The Bisurface knee prosthesis (BP) has a posterior stabilising cam (ball-and-socket joint) in the mid-posterior region of the femorotibial joint in an attempt to improve the range of movement. Based on an in vitro weight-bearing study contact areas of the Insall/Burstein 2 (IB2) and the BP knee were compared using pressure-sensitive films. The stability afforded by the cam was evaluated by means of dislocation distances in the vertical and horizontal planes.

Significant adverse anterior translation in mid-flexion was not observed with the BP knee since the cam was effective above 60° of flexion. At flexion of 60° or more, the total contact areas were larger, as the cam represented a weight-bearing surface. The dislocation distances for the BP knee compared favourably with those for the IB2 knee. We conclude that the cam of the BP knee allows good movement, stability and wear.

We investigated the effect of stimulation with a pulsed electromagnetic field on the osseointegration of hydroxyapatite in cortical bone in rabbits. Implants were inserted into femoral cortical bone and were stimulated for six hours per day for three weeks.

Electromagnetic stimulation improved osseointegration of hydroxyapatite compared with animals which did not receive this treatment in terms of direct contact with the bone, the maturity of the bone and mechanical fixation. The highest values of maximum push-out force (F_max) and ultimate shear strength (σ_u) were observed in the treated group and differed significantly from those of the control group at three weeks (F_max; p < 0.0001; σ_u, p < 0.0005).

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.

Clinical experience of the ICLH method of resurfacing the hip now spans 10 years. The first 36 arthroplasties, performed between 1972 and 1974, have been previously reported. This review covers in detail 204 such arthroplasties performed between 1975 and 1979 using a standard operative technique and prosthesis; these hips were consecutive and entirely unselected. Follow-up averaged 3.2 years (range two to six years). Successful hips are comparable to hips successfully replaced with stemmed prostheses. The rates of perioperative complications and failure due to infection, ectopic ossification, fracture of the femoral neck, and dislocation are favourably comparable to rates reported for stemmed total hip arthroplasties. The rate of aseptic loosening (17 per cent) greatly exceeded that found for stemmed total hip arthroplasties. Errors of patient selection, operative technique and prosthetic design have been identified. It is concluded that, although resurfacing arthroplasty of the hip may be an appealing procedure with theoretical advantages in certain instances, patient selection is essential, operative technique is demanding and changes in the design of the prosthesis are required. The procedure is still in evolution and therefore it should not yet be generally employed.

A series of 81 patients has been reviewed to determine the value of endoprosthetic replacement of the proximal femur and hip in the treatment of bone tumours. Standard statistical methods were used to evaluate the survival of the replacements and the patients. Taking removal of the prosthesis, irrespective of the cause, as the criterion for failure the survival of the replacements was found to be 63 per cent after 10 years. If deaths are regarded as failures, then the survival value falls to 48 per cent. The survival of patients with chondrosarcoma and osteoclastoma treated by endoprosthetic replacement compares favourably with survival after amputation or excision of the tumour.

Thirty patients with non-tuberculous pyogenic osteomyelitis of the spine are reported in all of whom the diagnosis was confirmed bacteriologically, histologically or serologically. The clinical and radiological features and investigations are analysed. Back pain, localised to the level involved, was the predominant symptom. The erythrocyte sedimentation rate was raised in all cases, and a characteristic sequence of radiological features is described.

This paper describes a simple method for the recording of rib deformity in idiopathic scoliosis. The relationships have been recorded between the measured rib hump and rib depression deformities and 1) the rotation of the vertebral bodies (as measured by the method of Nash and Moe on the standing radiograph); 2) the degree of lateral curvature (as measured by the method of Cobb on the standing radiograph); and 3) the rib-vertebra angles and their differences (as described by Mehta). No clear linear relationships were found. Many examples of irregular relationship were recorded, for example, marked spinal rotation with minimal rib hump. The response of the rib deformities to treatment by Milwaukee brace in fifty-two patients is described; the hump is little changed but the depression on the opposite side may be considerably reduced. Harrington instrumentation may have a similar effect.

1. If a vertical load is applied to the head of the femur parallel to its shaft, the upper cortex is stretched and the lower cortex is compressed. The neck breaks from the upper subcapital border to the lesser trochanter. This type of fracture is rarely found clinically.

2. If a compressive force is applied to the area between head and greater trochanter while the head is loaded vertically, a transverse fracture of clinical appearance is produced. If this axial pressure acts along the part of the neck above the central axis a subcapital comminuted fracture results. If the pressure acts below the central axis the result is a transcervical fracture.

3. Strain gauge experiments have shown that axial compression within the upper segment of the neck is produced by the abductor muscles of the hip. Adductor muscles produce a low axial compression. It is suggested that muscular action at the time of injury influences the type of fracture produced by the injury.