The clinical and radiological results of 50 consecutive acetabular reconstructions in 48 patients using impaction grafting have been retrospectively reviewed. A 1:1 mixture of frozen, ground irradiated bone graft and Apapore 60, a synthetic bone graft substitute, was used in all cases. There were 13 complex primary and 37 revision procedures with a mean follow-up of five years (3.4 to 7.6). The clinical survival rate was 100%, with improvements in the mean Harris Hip Scores for pain and function. Radiologically, 30 acetabular grafts showed evidence of incorporation, ten had radiolucent lines and two acetabular components migrated initially before stabilising.

Acetabular reconstruction in both primary and revision surgery using a 1:1 mixture of frozen, ground, irriadiated bone and Apapore 60 appears to be a reliable method of managing acetabular defects. Longer follow-up will be required to establish whether this technique is as effective as using fresh-frozen allograft.

Impaction allograft is an established method of securing initial stability of an implant in arthroplasty. Subsequent bone integration can be prolonged, and the volume of allograft may not be maintained. Intermittent administration of parathyroid hormone has an anabolic effect on bone and may therefore improve integration of an implant.

Using a canine implant model we tested the hypothesis that administration of parathyroid hormone may improve osseointegration of implants surrounded by bone graft. In 20 dogs a cylindrical porous-coated titanium alloy implant was inserted into normal cancellous bone in the proximal humerus and surrounded by a circumferential gap of 2.5 mm. Morsellised allograft was impacted around the implant. Half of the animals were given daily injections of human parathyroid hormone (1–34) 5 μg/kg for four weeks and half received control injections. The two groups were compared by mechanical testing and histomorphometry. We observed a significant increase in new bone formation within the bone graft in the parathyroid hormone group. There were no significant differences in the volume of allograft, bone-implant contact or in the mechanical parameters.

These findings suggest that parathyroid hormone improves new bone formation in impacted morsellised allograft around an implant and retains the graft volume without significant resorption. Fixation of the implant was neither improved nor compromised at the final follow-up of four weeks.

In Africa the amount of joint replacement surgery is increasing, but the indications for operation and the age of the patients are considerably different from those in the developed world. New centres with variable standards of care and training of the surgeons are performing these procedures and it is important that a proper audit of this work is undertaken.

In Malawi, we have pioneered a Registry which includes all joint replacements that have been carried out in the country. The data gathered include the age, gender, indication for operation, the prosthesis used, the surgical approach, the use of bone graft, the type of cement, pressurising systems and the thromboprophylaxis used. All patients have their clinical scores recorded pre-operatively and then after three and six months and at one year. Before operation all patients are counselled and on consent their HIV status is established allowing analysis of the effect of HIV on successful joint replacement.

To date, 73 total hip replacements (THRs) have been carried out in 58 patients by four surgeons in four different hospitals. The most common indications for THR were avascular necrosis (35 hips) and osteoarthritis (22 hips). The information concerning 20 total knee replacements has also been added to the Registry.

We systematically reviewed the peer-reviewed literature to relate the survival of hybrid metal-on-metal hip resurfacing arthroplasty devices to a National Institute of Clinical Excellence (NICE) benchmark for choosing a primary total hip replacement, which is a survival rate of 90% at a follow-up of ten years.

A total of 29 articles (10 621 resurfaced hips) met the inclusion criteria. The mean follow-up ranged from 0.6 to 10.5 years and the survival of the implant ranged from 84% to 100%. Of the 10 621 hips, 370 were revised (3.5%), with aseptic loosening as the most frequent mode of failure.

None of the hip resurfacing arthroplasty implants used to date met the full ten-year NICE benchmark of survival. A total of 13 studies showed satisfactory survival compared with the three-year NICE benchmark.

Pseudotumour is a rare but important complication of metal-on-metal hip resurfacing that occurs much more commonly in women than in men. We examined the relationship between head-neck ratio (HNR) and pseudotumour formation in 18 resurfaced hips (18 patients) revised for pseudotumour and 42 asymptomatic control resurfaced hips (42 patients).

Patients in whom pseudotumour formation had occurred had higher pre-operative HNR than the control patients (mean 1.37 (sd 0.10) vs mean 1.30 (sd 0.08) p = 0.001). At operation the patients with pseudotumours had a greater reduction in the size of their femoral heads (p = 0.035) and subsequently had greater neck narrowing (mean 10.1% (sd 7.2) vs mean 3.8% (sd 3.2) p < 0.001). No female patient with a pre-operative HNR ≤ 1.3 developed a pseudotumour.

We suggest that reducing the size of the femoral head, made possible by a high pre-operative HNR, increases the risk of impingement and edge loading, and may contribute to high wear and pseudotumour formation. As the incidence of pseudotumour is low in men, it appears safe to perform resurfacing in men. However, this study suggests that it is also reasonable to resurface in women with a pre-operative HNR ≤ 1.3.

We undertook a cemental unipolar proximal femoral endoprosthetic replacement in 131 patients with a mean age of 50 years (2 to 84). Primary malignant tumours were present in 54 patients and 67 had metastatic disease. In addition, eight patients had either lymphoma or myeloma and two had non-oncological disorders. The mean follow-up was 27 months (0 to 180). An acetabular revision was required later in 14 patients, 12 of whom had been under the age of 21 years at the time of insertion of their original prosthesis. The risk of acetabular revision in patients over 21 years of age was 8% at five years compared with 36% in those aged under 21 years. All the unipolar hips in this younger age group required revision within 11 years of the initial operation.

We conclude that unipolar replacement should not be used in younger patients and should be avoided in patients with a life expectancy of more than five years.

Wear of polyethylene is associated with aseptic loosening of orthopaedic implants and has been observed in hip and knee prostheses and anatomical implants for the shoulder. The reversed shoulder prostheses have not been assessed as yet. We investigated the volumetric polyethylene wear of the reversed and anatomical Aequalis shoulder prostheses using a mathematical musculoskeletal model. Movement and joint stability were achieved by EMG-controlled activation of the muscles. A non-constant wear factor was considered. Simulated activities of daily living were estimated from in vivo recorded data.

After one year of use, the volumetric wear was 8.4 mm³ for the anatomical prosthesis, but 44.6 mm³ for the reversed version. For the anatomical prosthesis the predictions for contact pressure and wear were consistent with biomechanical and clinical data. The abrasive wear of the polyethylene in reversed prostheses should not be underestimated, and further analysis, both experimental and clinical, is required.

In 2004 we described the ten-year prospective results of 38 total hip replacements using the Furlong hydroxyapatite-ceramic-coated femoral component in 35 patients < 50 years old. We have now reviewed the surviving 35 arthroplasties in 33 patients at a mean of 16 years (10.3 to 19.9). The mean age of the surviving patients at the time of operation was 41.3 years (26.0 to 49.0). Of these, eight have undergone revision of their acetabular component for aseptic loosening. None of the femoral components has had revision for aseptic loosening giving a survival rate of 100% at 16 years (95% confidence interval 89% to 100%).

The Furlong hydroxyapatite-ceramic-coated femoral component gives excellent long-term survival in young and active patients.

We have evaluated the in vivo migration patterns of 164 primary consecutive Charnley-Kerboull total hip replacements which were undertaken in 155 patients. The femoral preparation included removal of diaphyseal cancellous bone to obtain primary rotational stability of the stem before line-to-line cementing. We used the Ein Bild Roentgen Analyse femoral component method to assess the subsidence of the femoral component.

At a mean of 17.3 years (15.1 to 18.3) 73 patients were still alive and had not been revised, eight had been revised, 66 had died and eight had been lost to follow-up. The mean subsidence of the entire series was 0.63 mm (0.0 to 1.94). When using a 1.5 mm threshold, only four stems were considered to have subsided. Our study showed that, in most cases, a highly polished double-tapered stem cemented line-to-line does not subside at least up to 18 years after implantation.

The long-term success of total knee replacement is multifactorial, including factors relating to the patient, the operation and the implant. The purpose of this study was to examine the 20-year survival of the cemented Anatomical Graduated Component (AGC) total knee replacement. Between 1983 and 2004, 7760 of these were carried out at our institution. Of these, 6726 knees which received the non-modular metal-backed tibial component with compression-moulded polyethylene and had a minimum two-year follow-up were available for study. In all, 36 knees were followed over 20 years with a survival of the tibial and femoral components together of 97.8% (95% confidence interval (CI) 0.9851 to 0.9677), with no implants being revised for polyethylene wear or osteolysis. Age > 70 was associated with increased survival (99.6%, 95% CI 99.0 to 99.8) (p < 0.0001) but pre-operative valgus alignment reduced survival (95.1%, 95% CI 90.0 to 97.6) (p = 0.0056). Age < 55 (p = 0.129), pre-operative varus alignment (p = 0.707), osteonecrosis (p = 0.06), rheumatoid arthritis (p = 0.247), and gender (p = 0.666) were not statistically associated with failure.

We attribute the success of the AGC implant to its relatively unconstrained articular geometry and the durability of a non-modular metal-backed tibial component with compression moulded polyethylene.

The removal of well-fixed bone cement from the femoral canal during revision of a total hip replacement (THR) can be difficult and risks the loss of excessive bone stock and perforation or fracture of the femoral shaft. Retaining the cement mantle is attractive, yet the technique of cement-in-cement revision is not widely practised. We have used this procedure at our hospital since 1989. The stems were removed to gain a better exposure for acetabular revision, to alter version or leg length, or for component incompatibility.

We studied 136 hips in 134 patients and followed them up for a mean of eight years (5 to 15). A further revision was required in 35 hips (25.7%), for acetabular loosening in 26 (19.1%), sepsis in four, instability in three, femoral fracture in one and stem fracture in one. No femoral stem needed to be re-revised for aseptic loosening.

A cement-in-cement revision of the femoral stem is a reliable technique in the medium term. It also reduces the risk of perforation or fracture of the femoral shaft.

Second-generation metal-on-metal bearings were introduced as a response to the considerable incidence of wear-induced failures associated with conventional replacements, especially in young patients. We present the results at ten years of a consecutive series of patients treated using a metal-on-metal hip resurfacing. A distinct feature of the bearings used in our series was that they had been subjected to double-heat treatments during the post-casting phase of their manufacture. In the past these bearings had not been subjected to thermal treatments, making this a unique metal-on-metal bearing which had not been used before in clinical practice.

We report the outcome of 184 consecutive hips (160 patients) treated using a hybrid-fixed metal-on-metal hip resurfacing during 1996. Patients were invited for a clinicoradiological follow-up at a minimum of ten years. The Oxford hip score and anteroposterior and lateral radiographs were obtained. The mean age at operation was 54 years (21 to 75). A series of 107 consecutive hips (99 patients) who received the same prosthesis, but subjected to a single thermal treatment after being cast, between March 1994 and December 1995, were used as a control group for comparison.

In the 1994 to 1995 group seven patients (seven hips) died from unrelated causes and there were four revisions (4%) for osteolysis and aseptic loosening. In the 1996 group nine patients died at a mean of 6.9 years after operation because of unrelated causes. There were 30 revisions (16%) at a mean of 7.3 years (1.2 to 10.9), one for infection at 1.2 years and 29 for osteolysis and aseptic loosening. Furthermore, in the latter group there were radiological signs of failure in 27 (24%) of the 111 surviving hips.

The magnitude of the problem of osteolysis and aseptic loosening in the 1996 cohort did not become obvious until five years after the operation. Our results indicate that double-heat treatments of metal-on-metal bearings can lead to an increased incidence of wear-induced osteolysis.

Between 1989 and 1992 we had 102 knees suitable for unicompartmental knee replacement (UKR). They were randomised to receive either a St Georg Sled UKR or a Kinematic modular total knee replacement (TKR). The early results demonstrated that the UKR group had less complications and more rapid rehabilitation than the TKR group. At five years there were an equal number of failures in the two groups but the UKR group had more excellent results and a greater range of movement.

The cases were reviewed by a research nurse at 8, 10 and 12 years after operation. We report the outcome at 15 years follow-up. A total of 43 patients (45 knees) died with their prosthetic knees intact. Throughout the review period the Bristol knee scores of the UKR group have been better and at 15 years 15 (71.4%) of the surviving UKRs and 10 (52.6%) of the surviving TKRs had achieved an excellent score. The 15 years survivorship rate based on revision or failure for any reason was 24 (89.8%) for UKR and 19 (78.7%) for TKR. During the 15 years of the review four UKRs and six TKRs failed.

The better early results with UKR are maintained at 15 years with no greater failure rate. The median Bristol knee score of the UKR group was 91.1 at five years and 92 at 15 years, suggesting little functional deterioration in either the prosthesis or the remainder of the joint. These results justify the increased use of UKR.

We describe 129 consecutive revision total hip replacements using a Charnley-Kerboull femoral component of standard length with impaction allografting. The mean follow-up was 8.2 years (2 to 16). Additionally, extramedullary reinforcement was performed using struts of cortical allograft in 49 hips and cerclage wires in 30.

There was one intra-operative fracture of the femur but none later. Two femoral components subsided by 5 mm and 8 mm respectively, and were considered to be radiological failures. No further revision of a femoral component was required. The rate of survival of the femoral component at nine years, using radiological failure as the endpoint, was 98%. Our study showed that impaction grafting in association with a Charnley-Kerboull femoral component has a low rate of subsidence. Reconstruction of deficiencies of distal bone with struts of cortical allograft appeared to be an efficient way of preventing postoperative femoral fracture for up to 16 years.

We have updated our previous randomised controlled trial comparing release of chromium (Cr) and cobalt (Co) ions and included levels of titanium (Ti) ions. We have compared the findings from 28 mm metal-on-metal total hip replacement, performed using titanium CLS/Spotorno femoral components and titanium AlloFit acetabular components with Metasul bearings, with Durom hip resurfacing using a Metasul articulation or bearing and a titanium plasma-sprayed coating for fixation of the acetabular component.

Although significantly higher blood ion levels of Cr and Co were observed at three months in the resurfaced group than in total hip replacement, no significant difference was found at two years post-operatively for Cr, 1.58 μg/L and 1.62 μg/L respectively (p = 0.819) and for Co, 0.67 μg/L and 0.94 μg/L respectively (p = 0.207). A steady state was reached at one year in the resurfaced group and after three months in the total hip replacement group. Interestingly, Ti, which is not part of the bearing surfaces with its release resulting from metal corrosion, had significantly elevated ion levels after implantation in both groups. The hip resurfacing group had significantly higher Ti levels than the total hip replacement group for all periods of follow-up. At two years the mean blood levels of Ti ions were 1.87 μg/L in hip resurfacing and and 1.30 μg/L in total hip replacement (p = 0.001).

The study confirms even with different bearing diameters and clearances, hip replacement and 28 mm metal-on-metal total hip replacement produced similar Cr and Co metal ion levels in this randomised controlled trial study design, but apart from wear on bearing surfaces, passive corrosion of exposed metallic surfaces is a factor which influences ion concentrations. Ti plasma spray coating the acetabular components for hip resurfacing produces significantly higher release of Ti than Ti grit-blasted surfaces in total hip replacement.

We describe two cases of fracture of Corin Taper-Fit stems used for cement-in-cement revision of congenital dysplasia of the hip. Both prostheses were implanted in patients in their 50s, with high offsets (+7.5 mm and +3.5 mm), one with a large diameter (48 mm) head and one with a constrained acetabular component. Fracture of the stems took place at nine months and three years post-operatively following low-demand activity. Both fractures occurred at the most medial of the two stem introducer holes in the neck of the prosthesis, a design feature that is unique to the Taper-Fit stem. We would urge caution in the use of these particular stems for cement-in-cement revisions.

Hip simulators have been used for ten years to determine the tribological performance of large-head metal-on-metal devices using traditional test conditions. However, the hip simulator protocols were originally developed to test metal-on-polyethylene devices. We have used patient activity data to develop a more physiologically relevant test protocol for metal-on-metal devices. This includes stop/start motion, a more appropriate walking frequency, and alternating kinetic and kinematic profiles.

There has been considerable discussion about the effect of heat treatments on the wear of metal-on-metal cobalt chromium molybdenum (CoCrMo) devices. Clinical studies have shown a higher rate of wear, levels of metal ions and rates of failure for the heat-treated metal compared to the as-cast metal CoCrMo devices. However, hip simulator studies in vitro under traditional testing conditions have thus far not been able to demonstrate a difference between the wear performance of these implants.

Using a physiologically relevant test protocol, we have shown that heat treatment of metal-on-metal CoCrMo devices adversely affects their wear performance and generates significantly higher wear rates and levels of metal ions than in as-cast metal implants.

There are no long-term published results on the survival of a third-generation cemented total shoulder replacement. We describe a clinical and radiological study of the Aequalis total shoulder replacement for a minimum of ten years. Between September 1996 and May 1998, 39 consecutive patients underwent a primary cemented total shoulder replacement using this prosthesis. Data were collected prospectively on all patients each year, for a minimum of ten years, or until death or failure of the prosthesis. At a follow-up of at least ten years, 12 patients had died with the prosthesis intact and two had emigrated, leaving 25 available for clinical review. Of these, 13 had rheumatoid arthritis and 12 osteoarthritis. One refused radiological review leaving 24 with fresh radiographs.

Survivorship at ten years was 100% for the humeral component and 92% for the glenoid component. The incidence of lucent lines was low. No humeral component was thought to be at risk and only two glenoid components. The osteoarthritic group gained a mean 65° in forward flexion and their Constant score improved by a mean 41.4 points (13 to 55). The rheumatoid group gained a mean of 24° in flexion and their Constant score improved by 29.4 points. This difference may have been due to failure of the rotator cuff in 75% of the patients with rheumatoid arthritis.

Thus a third-generation total shoulder replacement gives an excellent result in patients with osteoarthritis and an intact rotator cuff. Patients with rheumatoid arthritis have a 75% risk of failure of the rotator cuff at ten years.

Cervical spinal disc replacement is used in the management of degenerative cervical disc disease in an attempt to preserve cervical spinal movement and to prevent adjacent disc overload and subsequent degeneration. A large number of patients have undergone cervical spinal disc replacement, but the effectiveness of these implants is still uncertain. In most instances, degenerative change at adjacent levels represents the physiological progression of the natural history of the arthritic disc, and is unrelated to the surgeon. Complications of cervical disc replacement include loss of movement from periprosthetic ankylosis and ossification, neurological deficit, loosening and failure of the device, and worsening of any cervical kyphosis. Strict selection criteria and adherence to scientific evidence are necessary. Only prospective, randomised clinical trials with long-term follow-up will establish any real advantage of cervical spinal disc replacement over fusion.

Payments by the NHS Litigation Authority continue to rise each year, and reflect an increase in successful claims for negligence against NHS Trusts. Information about the reasons for which Trusts are sued in the field of trauma and orthopaedic surgery is scarce.

We analysed 130 consecutive cases of alleged clinical negligence in which the senior author had been requested to act as an expert witness between 2004 and 2006, and received information on the outcome of 97 concluded cases from the relevant solicitors. None of the 97 cases proceeded to a court hearing. Overall, 55% of cases were abandoned by the claimants’ solicitors, and the remaining 45% were settled out of court. The cases were settled for sums ranging from £4500 to £2.7 million, the median settlement being £45 000. The cases that were settled out of court were usually the result of delay in treatment or diagnosis, or because of substandard surgical technique.