We describe a patient with cerebral palsy, of normal intelligence, who could not walk but who by the age of 16 had been successfully managed with a staged bilateral total hip arthroplasty using a constrained liner.

We evaluated the cost and consequences of proximal femoral fractures requiring further surgery because of complications. The data were collected prospectively in a standard manner from all patients with a proximal femoral fracture presenting to the trauma unit at the John Radcliffe Hospital over a five-year period. The total cost of treatment for each patient was calculated by separating it into its various components. The risk factors for the complications that arose, the location of their discharge and the mortality rates for these patients were compared to those of a matched control group. There were 2360 proximal femoral fractures in 2257 patients, of which 144 (6.1%) required further surgery. The mean cost of treatment in patients with complications was £18 709 (£2606.30 to £60.827.10), compared with £8610 (£918.54 to £45 601.30) for uncomplicated cases (p < 0.01), with a mean length of stay of 62.8 (44.5 to 79.3) and 32.7 (23.8 to 35.0) days, respectively. The probability of mortality after one month in these cases was significantly higher than in the control group, with a mean survival of 209 days, compared with 496 days for the controls. Patients with complications were statistically less likely to return to their own home (p < 0.01).

Greater awareness and understanding are required to minimise the complications of proximal femoral fractures and consequently their cost.

Hip resurfacing is being performed more frequently in the United Kingdom. The possible benefits include more accurate restoration of leg length, femoral offset and femoral anteversion than occurs after total hip arthroplasty (THA).

We compared anteroposterior radiographs from 26 patients who had undergone hybrid THA (uncemented cup/cemented stem), with 28 who had undergone Birmingham Hip Resurfacing arthroplasty (BHR). We measured the femoral offset, femoral length, acetabular offset and acetabular height with reference to the normal contralateral hip. The data were analysed by paired t-tests.

There was a significant reduction in femoral offset (p = 0.0004) and increase in length (p = 0.001) in the BHR group. In the THA group, there was a significant reduction in acetabular offset (p = 0.0003), but femoral offset and overall hip length were restored accurately. We conclude that hip resurfacing does not restore hip mechanics as accurately as THA.

The Morscher-Spotorno (MS-30) femoral stem is a stainless-steel, straight, three-dimensionally tapered, collarless implant for cemented fixation in total hip replacement.

We report the results at ten years of a consecutive series of 124 total hip replacements in 121 patients with the matt-surfaced MS-30 stem and an alumina ceramic head of 28-mm diameter. All the stems were fixed with Palacos bone cement with gentamicin using a modern cementing technique. They were combined with an uncemented, press-fit cup. The mean period of observation was 10.2 years (8.3 to 12.1) and no patient was lost to follow-up. Twenty-seven patients (22%) died with the implant in situ. Nine could only be interviewed by telephone. We included 85 patients with 88 hips in the clinical and radiological follow-up examinations.

None of the stems or cups had been revised. The Harris hip score was excellent or good in 97% (85 hips) and moderate in 3% (three hips). Radiologically, six hips (6.8%) had osteolysis adjacent to the stem, mostly in Gruen zone 7. Twenty (22.7%) showed one or more radiolucent lines. Twenty-two stems (25%) had subsided by 2 mm to 5 mm. In these cases two showed osteolysis (9.1%) with subsidence and four without (6.1%). Radiolucent lines were seen in seven with migration (31.8%) and in 13 without (19.7%). No infections and no acetabular osteolysis were observed.

The clinical results were excellent with survivorship after ten years of 100% and only a slightly statistically non-significant higher rate of osteolysis and radiolucency in cases of subsidence.

We present the medium-term results of hybrid total hip arthroplasties using pre-coated stems with a second-generation cementing technique. The 128 hips in 111 patients (18 men and 93 women) were followed up at a mean of 11 years after surgery. The mean age at the time of surgery was 61 years. Both components of one hip were removed at ten months after surgery for infection. None of the other 127 femoral components showed possible, probable, or definite loosening at the most recent follow-up. Five acetabular components were revised for aseptic loosening, recurrent dislocation, or displacement of the polyethylene liner from the metal shell. The mean Harris hip score at follow-up was 84 points. A pre-coated femoral component with a second-generation cementing technique provides good clinical function and survival in the medium term.

Polymethylmethacrylate remains one of the most enduring materials in orthopaedic surgery. It has a central role in the success of total joint replacement and is also used in newer techniques such as percutaneous vertebroplasty and kyphoplasty.

This article describes the current uses and limitations of polymethylmethacrylate in orthopaedic surgery. It focuses on its mechanical and chemical properties and links these to its clinical performance. The behaviour of antibiotic-loaded bone cement are discussed, together with areas of research that are now shedding light upon the behaviour of this unique biomaterial.

The use of impaction bone grafting during revision arthroplasty of the hip in the presence of cortical defects has a high risk of post-operative fracture. Our laboratory study addressed the effect of extramedullary augmentation and length of femoral stem on the initial stability of the prosthesis and the risk of fracture.

Cortical defects in plastic femora were repaired using either surgical mesh without extramedullary augmentation, mesh with a strut graft or mesh with a plate. After bone impaction, standard or long-stem Exeter prostheses were inserted, which were tested by cyclical loading while measuring defect strain and migration of the stem.

Compared with standard stems without extramedullary augmentation, defect strains were 31% lower with longer stems, 43% lower with a plate and 50% lower with a strut graft. Combining extramedullary augmentation with a long stem showed little additional benefit (p = 0.67). The type of repair did not affect the initial stability. Our results support the use of impaction bone grafting and extramedullary augmentation of diaphyseal defects after mesh containment.

The role of vacuum mixing on the reduction of porosity and on the clinical performance of cemented total hip replacements remains uncertain. We have used paired femoral constructs prepared with either hand-mixed or vacuum-mixed cement in a cadaver model which simulated intra-operative conditions during cementing of the femoral component. After the cement had cured, the distribution of its porosity was determined, as was the strength of the cement-stem and cement-bone interfaces.

The overall fraction of the pore area was similar for both hand-mixed and vacuum-mixed cement (hand 6%; vacuum 5.7%; paired t-test, p = 0.187). The linear pore fractions at the interfaces were also similar for the two techniques. The pore number-density was much higher for the hand-mixed cement (paired t-test, p = 0.0013). The strength of the cement-stem interface was greater with the hand-mixed cement (paired t-test, p = 0.0005), while the strength of the cement-bone interface was not affected by the conditions of mixing (paired t-test, p = 0.275). The reduction in porosity with vacuum mixing did not affect the porosity of the mantle, but the distribution of the porosity can be affected by the technique of mixing used.

We investigated 219 revisions of total hip replacement (THR) in 211 patients using a collarless double-taper cemented femoral component. The mean age of the patients was 72 years (30 to 90). The 137 long and 82 standard length stems were analysed separately. The mean follow-up was six years (2 to 18), and no patient was lost to follow-up.

Survival of the long stems to re-revision for aseptic loosening at nine years was 98% (95% confidence interval (CI) 94 to 100), and for the standard stems was 93% (95% CI 85 to 100). At five years, one long stem was definitely loose radiologically and one standard stem was probably loose. Pre-operative femoral bone deficiency did not influence the results for the long stems, and corrective femoral osteotomy was avoided, as were significant subsidence, major stress shielding and persistent thigh pain.

Because of these reliable results, cemented long collarless double-taper femoral components are recommended for routine revision THR in older patients.

Impacted morsellised allografts have been used successfully to address the problem of poor bone stock in revision surgery. However, there are concerns about the transmission of pathogens, the high cost and the shortage of supply of donor bone. Bone-graft extenders, such as tricalcium phosphate (TCP) and hydroxyapatite (HA), have been developed to minimise the use of donor bone. In a human cadaver model we have evaluated the surgical and mechanical feasibility of a TCP/HA bone-graft extender during impaction grafting revision surgery.

A TCP/HA allograft mix increased the risk of producing a fissure in the femur during the impaction procedure, but provided a higher initial mechanical stability when compared with bone graft alone. The implications of the use of this type of graft extender in impaction grafting revision surgery are discussed.

We undertook a review of the literature relating to the two basic stem designs in use in cemented hip replacement, namely loaded tapers or force-closed femoral stems, and the composite beam or shape-closed designs. The associated stem fixation theory as understood from in vitro studies and finite element modelling were examined with reference to the survivorship results for each of the concepts of fixation.

It is clear that both design principles are capable of producing successful long-term results, providing that their specific requirements of stem metallurgy, shape and surface finish, preparation of the bone and handling of the cement are observed.

Aseptic loosening of the acetabular component continues to be the most common indication for revision of total hip replacements in younger patients. Early in the evolution of the cemented hip, arthroplasty surgeons switched from removal to retention of the acetabular subchondral bone plate, theorising that unfavourable mechanical forces were the cause of loosening at the bone-cement interface.

It is now known that the cause of aseptic loosening is probably biological rather than mechanical and removing the subchondral bone plate may enhance biological fixation of cement to bone. With this in mind, perhaps it is time to revive removal of the subchondral bone as a standard part of acetabular preparation.

Metallosis is a rare cause of failure after total knee replacement and has only previously been reported when there has been abnormal metal-on-metal contact. We describe 14 patients (15 knees) whose total knee replacement required revision for a new type of early failure caused by extensive metallosis. A modification of a cementless rotating platform implant, which had previously had excellent long-term survival, had been used in each case. The change was in the form of a new porous-beaded surface on the femoral component to induce cementless fixation, which had been used successfully in the fixation of acetabular and tibial components. This modification appeared to have resulted in metallosis due to abrasive two-body wear. The component has subsequently been recalled and is no longer in use. The presentation, investigation, and findings at revision are described and a possible aetiology and its implications are discussed.

Pathological fractures due to metastasis with destruction of the acetabulum and central dislocation of the hip present a difficult surgical challenge. We describe a series using a single technique in which a stable and long-lasting reconstruction was obtained using standard primary hip replacement implants augmented by strong, fully-threaded steel rods with cement and steel mesh, where required.

Between 1997 and 2006, 19 patients with a mean age of 66 years (48 to 83) were treated using a modified Harrington technique. Acetabular destruction was graded as Harrington class II in six cases and class III in 13.

Reconstruction was achieved using three 6.5 mm rods inserted through a separate incision in the iliac crest followed by augmentation with cement and a conventional cemented Charnley or Exeter primary hip replacement. There were no peri-operative deaths. At the final follow-up (mean 25 months (5 to 110)) one rod had fractured and one construct required revision. Of the 18 patients who did not require revision, 13 had died. The mean time to death was 16 months (5 to 55). The mean follow-up of the five survivors was 31 months (18 to 47). There were no cases of dislocation, deep infection or injury to a nerve, the blood vessels or the bladder.

Loss of bone stock is a major problem in revision surgery of the hip. Impaction bone grafting of the femur is frequently used when dealing with deficient bone stock. In this retrospective study a consecutive series of 68 patients (69 hips) who had revision of a hip replacement with femoral impaction grafting were reviewed. Irradiated bone allograft was used in all hips. Radiological measurement of subsidence of the stem, incorporation of the graft and remodelling was carried out and showed incorporation of the graft in 26 of 69 hips (38%). However, there was no evidence of trabecular remodelling. Moderate subsidence of 5 mm to 10 mm occurred in ten hips (14.5%), and massive subsidence of > 10 mm in five (7.2%).

The results of this study are less favourable than those of others describing studies of revision of the femoral stem using impaction bone grafting. The absence of the characteristic changes of graft remodelling noted in other series raises the question as to whether irradiated bone graft may be a significant factor influencing the post-operative outcome.

Resurfacing arthroplasty of the hip is being performed more frequently in the United Kingdom. The majority of these patients are younger than 55 years of age, and in this group the key benefits include conservation of femoral bone stock and the potential reduction in the rate of dislocation afforded by the larger resurfacing head. Early aseptic loosening is well recognised in patients younger than 55 years of age, and proponents of resurfacing believe that the improved wear characteristics of the metal-on-metal bearing may improve the long-term survival of this implant. There has been some concern, however, that resurfacing may not be conservative of acetabular bone.

We compared a series of 33 consecutive patients who had a hybrid total hip arthroplasty with an uncemented acetabular component and a cemented femoral implant, with 35 patients undergoing a Birmingham hip resurfacing arthroplasty. We compared the diameter of the implanted acetabulum in both groups and, because they were not directly comparable, we corrected for patient size by measuring the diameter of the contralateral femoral head. The data were analysed using unpaired t-tests and analysis of covariance.

There was a significantly larger acetabulum in the Birmingham arthroplasty group (mean diameter 56.6 mm vs 52.0 mm; p < 0.001). However, this group had a significantly larger femoral head diameter on the contralateral side (p = 0.03). Analysis of covariance revealed a significant difference between the mean size of the acetabular component implanted in the two operations. The greatest difference in the size of acetabulum was in those patients with a larger diameter of the femoral head. This study shows that more bone is removed from the acetabulum in hip resurfacing than during hybrid total hip arthroplasty, a difference which is most marked in larger patients.

We reviewed the clinical and radiological results of 131 patients who underwent acetabular revision for aseptic loosening with impacted bone allograft and a cemented acetabular component. The mean follow-up was 51.7 months (24 to 156).

The mean post-operative Merle D’Aubigné and Postel scores were 5.7 points (4 to 6) for pain, 5.2 (3 to 6) for gait and 4.5 (2 to 6) for mobility. Radiological evaluation revealed migration greater than 5 mm in four acetabular components. Radiological failure matched clinical failure. Asymptomatic radiolucent lines were observed in 31 of 426 areas assessed (7%). Further revision was required in six patients (4.5%), this was due to infection in three and mechanical failure in three. The survival rate for the reconstruction was 95.8% (95% confidence interval 92.3 to 99.1) overall, and 98%, excluding revision due to sepsis.

Our study, from an independent centre, has reproduced the results of the originators of the method.