We retrospectively reviewed 35 cemented unicompartmental knee replacements performed for medial unicompartmental osteoarthritis of the knee in 31 patients ≤50 years old (mean 46, 31 to 49). Patients were assessed clinically and radiologically using the Knee Society scores at a mean follow-up of 9.7 years (5 to 16) and survival at 12 years was calculated. The mean Knee Society Function Score improved from 54 points (25 to 64) pre-operatively to 89 (80 to 100) post-operatively (p < 0.0001). Six knees required revision, four for polyethylene wear treated with an isolated exchange of the tibial insert, one for aseptic loosening and one for progression of osteoarthritis.

The 12-year survival according to Kaplan-Meier was 80.6% with revision for any reason as the endpoint. Despite encouraging clinical results, polyethylene wear remains a major concern affecting the survival of unicompartmental knee replacement in patients younger than 50.

Radiographs of 110 patients who had undergone 120 high tibial osteotomies (60 closed-wedge, 60 open-wedge) were assessed for posterior tibial slope before and after operation, and before removal of the hardware. In the closed-wedge group the mean slope was 5.7° (sd 3.8) before and 2.4° (sd 3.9) immediately after operation, and 2.4° (sd 3.4) before removal of the hardware. In the open-wedge group, these values were 5.0° (sd 3.7), 7.7° (sd 4.3) and 8.1° (sd 3.9) respectively, when stabilised with a non-locking plate, and 7.7° (sd 3.5), 9.4° (sd 4.1) and 9.1° (sd 3.8), when stabilised with a locking plate. The reduction in slope (−2.7° (sd 4.1)) in the closed-wedge group and the increase (+2.5° (sd 3.4), in the open-wedge group was significantly different before and after operation (p = 0.002, p = 0.003). In no group were the changes in slope directly after operation and before removal of the hardware significant (p > 0.05). There was no correlation between the amount of correction in the frontal plane and the post-operative change in slope.

Posterior tibial slope decreases after closed-wedge high tibial osteotomy and increases after an open-wedge procedure because of the geometry of the proximal tibia. The changes in the slope are stable over time, emphasising the influence of the operative procedure rather than of the implant.

Infection of a total hip replacement (THR) requires component removal and thorough local debridement. Usually, long-term antibiotic treatment in conjunction with a two-stage revision is required. This may take several months. One-stage revision using antibiotic-loaded cement has not gained widespread use, although the clinical and economic advantages are obvious. Allograft bone may be impregnated with high levels of antibiotics, and in revision of infected THR, act as a carrier providing a sustained high local concentration.

We performed 37 one-stage revision of infected THRs, without the use of cement. There were three hips which required further revision because of recurrent infection, the remaining 34 hips (92%) stayed free from infection and stable at a mean follow-up of 4.4 years (2 to 8). No adverse effects were identified. Incorporation of bone graft was comparable with unimpregnated grafts.

Antibiotic-impregnated allograft bone may enable reconstruction of bone stock, insertion of an uncemented implant and control of infection in a single operation in revision THR for infection.

We present a series of 30 uncemented total hip replacements performed between June 1985 and January 2002 with a mean follow-up of seven years (5 to 20) in 27 patients who had previously undergone a valgus intertrochanteric osteotomy. No further osteotomy was undertaken to enable hip replacement. We used a number of uncemented modular or monoblock femoral components, acetabular components and bearings. The patients were followed up clinically and radiologically. We report 100% survival of the femoral component. One acetabular component was revised at five years post-implantation for aseptic loosening. We noted cortical hypertrophy around the tip of the monoblock stems in six patients. We believe that modular femoral components should be used when undertaking total hip replacement in patients who have previously undergone valgus femoral osteotomy.

We reviewed the results at nine to 13 years of 125 total hip replacements in 113 patients using the monoblock uncemented Morscher press-fit acetabular component. The mean age at the time of operation was 56.9 years (36 to 74). The mean clinical follow-up was 11 years (9.7 to 13.5) and the mean radiological follow-up was 9.4 years (7.7 to 13.1). Three hips were revised, one immediately for instability, one for excessive wear and one for deep infection.

No revisions were required for aseptic loosening. A total of eight hips (7.0%) had osteolytic lesions greater than 1 cm, in four around the acetabular component (3.5%). One required bone grafting behind a well-fixed implant. The mean wear rate was 0.11 mm/year (0.06 to 0.78) and was significantly higher in components with a steeper abduction angle.

Kaplan-Meier survival curves at 13 years showed survival of 96.8% (95% confidence interval 90.2 to 99.0) for revision for any cause and of 95.7% (95% confidence interval 88.6 to 98.4) for any acetabular re-operation.

We undertook a prospective randomised controlled trial to investigate the efficacy of autologous retransfusion drains in reducing the need for allogenic blood requirement after unilateral total knee replacement. We also monitored the incidence of post-operative complications. There were 86 patients in the control group, receiving standard care with a vacuum drain, and 92 who received an autologous drain and were retransfused postoperatively. Following serial haemoglobin measurements at 24, 48 and 72 hours, we found no difference in the need for allogenic blood between the two groups (control group 15.1%, retransfusion group 13% (p = 0.439)). The incidence of post-operative complications, such as wound infection, deep-vein thrombosis and chest infection, was also comparable between the groups. There were no adverse reactions associated with the retransfusion of autologous blood.

Based on this study, the cost-effectiveness and continued use of autologous drains in total knee replacement should be questioned.

Muscle atrophy has been demonstrated in patients suffering from osteoarthritis of the hip, but little is known about muscular recovery after total hip replacement (THR). A total of 20 patients with unilateral osteoarthritis of the hip were assessed before, six months and two years after THR. The cross-sectional area and radiological density of the muscles of the hip, thigh, calf and back were measured using CT. We hypothesised that the muscles would not recover fully after operation.

After two years comparison of the limb with the THR with the healthy limb showed that there was such a reduction in the cross-sectional area in iliopsoas (7.0%; p = 0.006) and the hip adductors (8.4%, p = 0.003) and in the radiological density in gluteus maximus (10.1 Hounsfield units; p < 0.001), gluteus medius/minimus (5.6 Hounsfield units; p = 0.011), iliopsoas (3.9 Hounsfield units; p < 0.001) and the adductors (2.4 Hounsfield units; p = 0.022).

Thus, there was persistent muscle atrophy in muscles acting about the hip two years after THR. We suggest that an earlier operation or a more intensive rehabilitation may reverse these changes.

We have studied the concept of posterior condylar offset and the importance of its restoration on the maximum range of knee flexion after posterior-cruciate-ligament-retaining total knee replacement (TKR). We measured the difference in the posterior condylar offset before and one year after operation in 69 patients who had undergone a primary cruciate-sacrificing mobile bearing TKR by one surgeon using the same implant and a standardised operating technique. In all the patients true pre- and post-operative lateral radiographs had been taken.

The mean pre- and post-operative posterior condylar offset was 25.9 mm (21 to 35) and 26.9 mm (21 to 34), respectively. The mean difference in posterior condylar offset was + 1 mm (−6 to +5). The mean pre-operative knee flexion was 111° (62° to 146°) and at one year postoperatively, it was 107° (51° to 137°).

There was no statistical correlation between the change in knee flexion and the difference in the posterior condylar offset after TKR (Pearson correlation coefficient r = −0.06, p = 0.69).

Polyethylene wear of acetabular components is a key factor in the development of periprosthetic osteolysis and wear at the articular surface has been well documented and quantified, but fewer data are available about changes which occur at the backside of the liner.

At revision surgery for loosening of the femoral component we retrieved 35 conventional modular acetabular liners of the same design. Linear and volumetric articular wear, backside volumetric change and the volume of the screw-head indentations were quantified. These volumes, clinical data and the results from radiological Ein Bild Röntgen Analyse migration analysis were used to identify potential factors influencing the volumetric articular wear and backside volumetric change.

The rate of backside volumetric change was found to be 2.8% of the rate of volumetric articular wear and decreased with increasing liner size. Migrated acetabular components showed significantly higher rates of backside volumetric change plus screw-head indentations than those without migration.

The backside volumetric change was at least ten times larger than finite-element simulation had suggested. In a stable acetabular component with well-anchored screws, the amount of backside wear should not cause clinical problems. Impingement of the screw-heads could produce more wear particles than those generated at the liner-shell interface. Because the rate of backside volumetric change is only 2.8% of the rate of volumetric articular wear and since creep is likely to contribute a significant portion to this, the debris generated by wear at the backside of the liner may not be sufficient to create a strong osteolytic response.

We carried out a prospective study to assess the clinical outcome, complications and survival of the NexGen Legacy posterior-stabilised-Flex total knee replacement (TKR) in a consecutive series of 278 knees between May 2003 and February 2005. Mean follow-up for 259 TKRs (98.2%) was 3.8 years (3.0 to 4.8). Annual follow-up showed improvement in the Knee Society scores (paired t-test, p < 0.05). At the last follow-up, the mean maximum flexion was 135° (110° to 150°). Two knees showed radiolucent lines, but revision was not required because the patients were asymptomatic. Revision was required in one case because of infection, but there were no prosthesis-related revisions. There were no other complications. The estimated survival rate at four years with revision for any reason and prosthesis-related problems was 99.6% and 100%, respectively.

This relatively large study indicates that the legacy posterior stabilised-Flex design provides excellent short-term outcome but warrants ongoing evaluation to confirm the long-term durability and functioning of the implant.

In a randomised study, 28 patients with a mean age of 62.2 years (32 to 81) with osteoarthritis or avascular necrosis of the hip received either a ceramic-on-ceramic or a metal-on-metal total hip replacement. Apart from the liners the acetabular and femoral components were made of Ti-Al-Nb alloy. The serum aluminium and cobalt levels were measured before, and at one year after surgery.

The 15 patients in the ceramic-on-ceramic group had a median pre-operative aluminium level of 1.3 μg/l (0.25 to 8.4) and a cobalt level below the detection limit. At one year the aluminium level was 1.1 μg/l (0.25 to 2.3) and the cobalt level was 0.4 μg/l (0.15 to 0.7). The 13 patients in the metal-on-metal group had a median pre-operative aluminium level of 1.9 μg/l (0.25 to 4.4) and a cobalt level below the detection limit. At one year the median aluminium level was 0.9 μg/l (0.25 to 3.9) whereas the cobalt level was 1.4 μg/l (0.5 to 10.5). This increase in the cobalt level at one year was significant (p < 0.001).

Our findings indicate that ceramic-on-ceramic bearings do not cause elevated levels of serum aluminium in the first post-operative year.

Polyethylene liners of modular acetabular components wear sometimes need to be replaced, despite the metal shell being well fixed. Replacing the liner is a relatively simple procedure, but very little is known of the outcome of revision. We prospectively followed up 1126 Harris-Galante I metal-backed, uncemented components for between nine and 19 years. We found 38 (3.4%) liners of 1126 acetabular components wore and required revision. These revisions were then followed up for a mean of 4.8 years. The rate of dislocation was 28.9%. Nine of the dislocations occurred once and two were recurrent.

The overall secondary revision rate was three of 38 total hip replacements (7.9%) at a mean follow-up of 4.8 years. This gives a 92.1% survivorship (35 of 38) at under five years. In isolated revision of a liner, we had a complication rate of 23% (three of 13). In revision of a liner combined with revision of the femoral stem, there was a complication rate of 48% (12 of 25). We discuss possible reasons for the high dislocation rates.

Leaving the well-fixed acetabular shell in situ leads to an increased risk of instability. However, this needs to be balanced against the otherwise low complication rate for revision of the liner. Patients should be consented accordingly.

Between 1988 and 2006, 18 patients had a custom-made endoprosthetic replacement of the distal humerus for bone tumours at our institution. There were 11 primary malignant neoplasms, six secondary deposits, and one benign aggressive tumour. The mean follow-up was for 4.4 years (1 to 18.2). Complications occurred in nine patients and included aseptic loosening in three (16.6%), local recurrence in two (11%), infection in two (11%), neuropraxia of the radial nerve in one (5.5%) and a peri-prosthetic fracture in one (5.5%). Excision was inadequate in four patients (22%), all of which developed local recurrence and/or metastases. There were seven deaths from the primary disease after a mean of 2.3 years (1 to 5), one of whom had an above-elbow amputation for local recurrence seven months before death. The remaining six had satisfactory elbow function at their last follow-up. The 11 living patients were evaluated using the Musculoskeletal Tumour Society and Toronto Extremity Salvage scoring systems. The mean scores achieved were 76% (67% to 87%) and 73% (59% to 79%), respectively. Overall, 17 of 18 patients had significant improvement in the degree of their pain following operation.

Custom-made endoprosthetic reconstruction of the elbow for bone tumours is a viable treatment in carefully selected patients. It maintains satisfactory function and provides good pain relief.

Modifications in the design of knee replacements have been proposed in order to maximise flexion. We performed a prospective double-blind randomised controlled trial to compare the functional outcome, including maximum knee flexion, in patients receiving either a standard or a high flexion version of the NexGen legacy posterior stabilised total knee replacement. A total of 56 patients, half of whom received each design, were assessed pre-operatively and at one year after operation using knee scores and analysis of range of movement using electrogoniometry. For both implant designs there was a significant improvement in the function component of the knee scores (p < 0.001) and the maximum range of flexion when walking on the level, ascending and descending a slope or stairs (all p < 0.001), squatting (p = 0.020) and stepping into a bath (p = 0.024). There was no significant difference in outcome, including the maximum knee flexion, between patients receiving the standard and high flexion designs of this implant.

We have performed a prospective double-blind, randomised controlled trial over two years to evaluate the efficacy and safety of an intra-operative peri-articular injection of triamcinolone acetonide in patients undergoing medial unicondylar knee replacement. We randomised 90 patients into two equal groups. The study group received an injection of triamcinolone acetonide, bupivacaine, and epinephrine into the peri-articular tissues at the end of the operation. The control group received the same injection mixture but without the addition of triamcinolone. The peri-operative analgesic regimen was standardised.

The study group reported a significant reduction in pain (p = 0.014 at 12 hours, p = 0.031 at 18 hours and p = 0.031 at 24 hours) and had a better range of movement (p = 0.023 at three months). There was no significant difference in the rate of infection and no incidence of tendon rupture in either group.

The addition of corticosteroid to the peri-articular injection after unicondylar knee replacement had both immediate and short-term benefits in terms of relief from pain, and rehabilitation with no increased risk of infection.

We assessed leg length discrepancy and hip function in 90 patients undergoing primary total hip arthroplasty before surgery and at three and 12 months after. Function was measured using the Oxford hip score (OHS). After surgery the mean OHS improved by 26 points after three months and by 30 points after 12.

After operation 56 (62%) limbs were long by a mean of 9 mm and this was perceived by 24 (43%) patients after three months and by 18 (33%) after 12. The mean OHS in patients who perceived true lengthening was 27% worse than the rest of the population after three months and 18% worse after 12. In 55 (98%) patients, lengthening occurred in the femoral component. Appropriate placement of the femoral component could significantly reduce a patient’s perception of discrepancy of length.

Between 1993 and 2002, 58 GSB III total elbow replacements were implanted in 45 patients with rheumatoid arthritis by the same surgeon. At the most recent follow-up, five patients had died (five elbows) and six (nine elbows) had been lost to follow-up, leaving 44 total elbow replacements in 34 patients available for clinical and radiological review at a mean follow-up of 74 months (25 to 143). There were 26 women and eight men with a mean age at operation of 55.7 years (24 to 77).

At the latest follow-up, 31 excellent (70%), six good (14%), three fair (7%) and four poor (9%) results were noted according to the Mayo elbow performance score. Five humeral (11%) and one ulnar (2%) component were loose according to radiological criteria (type III or type IV). Of the 44 prostheses, two (5%) had been revised, one for type-IV humeral loosening after follow-up for ten years and one for fracture of the ulnar component. Seven elbows had post-operative dysfunction of the ulnar nerve, which was transient in five and permanent in two.

Despite an increased incidence of loosening with time, the GSB III prosthesis has given favourable mid-term results in patients with rheumatoid arthritis.

The use of allograft struts and cerclage wire, possibly augmented by plate fixation, for the treatment of Vancouver type-B1 peri-prosthetic fractures around a total hip replacement has been strongly advocated. We examined our results using plate fixation without allograft struts and compared them with the results of the use of struts alone or when combined with plate fixation. Of 20 consecutive patients with type-B1 fractures treated by open reduction and plate fixation, 19 were available for follow-up. The fractures healed in 18 patients with a mean time to weight-bearing of ten weeks (4 to 19). There were no cases of infection or malunion. Nonunion occurred in one patient and required a second plate fixation to achieve union.

Safe, cost-effective treatment of Vancouver type-B1 fractures can be performed by plate fixation without the addition of cortical struts. This procedure may allow earlier weight-bearing than allograft strut fixation alone.

Finite element analysis was used to examine the initial stability after hip resurfacing and the effect of the procedure on the contact mechanics at the articulating surfaces. Models were created with the components positioned anatomically and loaded physiologically through major muscle forces. Total micromovement of less than 10 μm was predicted for the press-fit acetabular components models, much below the 50 μm limit required to encourage osseointegration. Relatively high compressive acetabular and contact stresses were observed in these models. The press-fit procedure showed a moderate influence on the contact mechanics at the bearing surfaces, but produced marked deformation of the acetabular components. No edge contact was predicted for the acetabular components studied.

It is concluded that the frictional compressive stresses generated by the 1 mm to 2 mm interference-fit acetabular components, together with the minimal micromovement, would provide adequate stability for the implant, at least in the immediate post-operative situation.

We have reviewed a group of patients with iliopsoas impingement after total hip replacement with radiological evidence of a well-fixed malpositioned or oversized acetabular component. A consecutive series of 29 patients (30 hips) was assessed. All had undergone a trial of conservative management with no improvement in their symptoms. Eight patients (eight hips) preferred continued conservative management (group 1), and 22 hips had either an iliopsoas tenotomy (group 2) or revision of the acetabular component and debridement of the tendon (group 3), based on clinical and radiological findings. Patients were followed clinically for at least two years, and 19 of the 22 patients (86.4%) who had surgery were contacted by phone at a mean of 7.8 years (5 to 9) post-operatively. Conservative management failed in all eight hips. At the final follow-up, operative treatment resulted in relief of pain in 18 of 22 hips (81.8%), with one hip in group 2 and three in group 3 with continuing symptoms. The Harris Hip Score was significantly better in the combined groups 2 and 3 than in group 1. There was a significant rate of complications in group 3. This group initially had better functional scores, but at final follow-up these were no different from those in group 2.

Tenotomy of the iliopsoas and revision of the acetabular component are both successful surgical options. Iliopsoas tenotomy provided the same functional results as revision of the acetabular component and avoided the risks of the latter procedure.