Three-dimensional surface models of the normal hemipelvis derived from volumetric CT data on 42 patients were used to determine the radius, depth and orientation of the native acetabulum. A sphere fitted to the lunate surface and a plane matched to the acetabular rim were used to calculate the radius, depth and anatomical orientation of the acetabulum. For the 22 females the mean acetabular abduction, anteversion, radius and normalised depth were 57.1° (50.7° to 66.8°), 24.1° (14.0° to 33.3°), 25 mm (21.7 to 30.3) and 0.79 mm (0.56 to 1.04), respectively. The same parameters for the 20 males were 55.5° (47.7° to 65.9°), 19.3° (8.5° to 32.3°), 26.7 mm (24.5 to 28.7) and 0.85 mm (0.65 to 0.99), respectively.

The orientation of the native acetabulum did not match the safe zone for acetabular component placement described by Lewinnek. During total hip replacement surgeons should be aware that the average abduction angle of the native acetabulum exceeds that of the safe zone angle. If the concept of the safe zone angle is followed, abduction of the acetabular component should be less than the abduction of the native acetabulum by approximately 10°.

The Cementless Oxford Unicompartmental Knee Replacement (OUKR) was developed to address problems related to cementation, and has been demonstrated in a randomised study to have similar clinical outcomes with fewer radiolucencies than observed with the cemented device. However, before its widespread use it is necessary to clarify contraindications and assess the complications. This requires a larger study than any previously published.

We present a prospective multicentre series of 1000 cementless OUKRs in 881 patients at a minimum follow-up of one year. All patients had radiological assessment aligned to the bone–implant interfaces and clinical scores. Analysis was performed at a mean of 38.2 months (19 to 88) following surgery. A total of 17 patients died (comprising 19 knees (1.9%)), none as a result of surgery; there were no tibial or femoral loosenings. A total of 19 knees (1.9%) had significant implant-related complications or required revision. Implant survival at six years was 97.2%, and there was a partial radiolucency at the bone–implant interface in 72 knees (8.9%), with no complete radiolucencies. There was no significant increase in complication rate compared with cemented fixation (p = 0.87), and no specific contraindications to cementless fixation were identified.

Cementless OUKR appears to be safe and reproducible in patients with end-stage anteromedial osteoarthritis of the knee, with radiological evidence of improved fixation compared with previous reports using cemented fixation.

Cite this article: Bone Joint J 2013;95-B:181–7.

The October 2012 Hip & Pelvis Roundup³⁶⁰ looks at: diagnosing the infected hip replacement; whether tranexamic acid has a low complication rate; the relationship between poor cementing technique and early failure of resurfacing; debridement and retention for the infected replacement; triple-tapered stems and bone mineral density; how early discharge can be bad for your sleep; an updated QFracture algorithm to predict the risk of an osteoporotic fracture; and local infiltration analgesia and total hip replacement.

We describe a technique to salvage a painful hemiarthroplasty due to erosion of the acetabular cartilage in the absence of loosening of the femoral component. A press-fit metallic acetabular component which matched the femoral component was used as a metal-on-metal articulation. The procedure offered a shorter operation time with less blood loss and no risk of femoral fracture as might have occurred during conventional revision to a total hip replacement. The patient made an unremarkable recovery with a good outcome at follow-up of 15 months.

We live in troubled times. Increased opposition reliance on explosive devices, the widespread use of individual and vehicular body armour, and the improved survival of combat casualties have created many complex musculoskeletal injuries in the wars in Iraq and Afghanistan. Explosive mechanisms of injury account for 75% of all musculoskeletal combat casualties. Throughout all the echelons of care medical staff practice consistent treatment strategies of damage control orthopaedics including tourniquets, antibiotics, external fixation, selective amputations and vacuum-assisted closure. Complications, particularly infection and heterotopic ossification, remain frequent, and re-operations are common. Meanwhile, non-combat musculoskeletal casualties are three times more frequent than those derived from combat and account for nearly 50% of all musculoskeletal casualties requiring evacuation from the combat zone.

The Oxford unicompartmental knee replacement (UKR) is an established treatment option in the management of symptomatic end-stage medial compartmental osteoarthritis (MCOA), which works well in the young and active patient. However, previous studies have shown that it is reliable only in the presence of a functionally intact anterior cruciate ligament (ACL). This review reports the outcomes, at a mean of five years and a maximum of ten years, of 52 consecutive patients with a mean age of 51 years (36 to 57) who underwent staged or simultaneous ACL reconstruction and Oxford UKR. At the last follow-up (with one patient lost to follow-up), the mean Oxford knee score was 41 (sd 6.3; 17 to 48). Two patients required conversion to TKR: one for progression of lateral compartment osteoarthritis and one for infection. Implant survival at five years was 93% (95% CI 83 to 100). All but one patient reported being satisfied with the procedure. The outcome was not significantly influenced by age, gender, femoral or tibial tunnel placement, or whether the procedure was undertaken at one- or two-stages.

In summary, ACL reconstruction and Oxford UKR gives good results in patients with end-stage MCOA secondary to ACL deficiency.

Implantation of a large-diameter femoral head prosthesis with a metal-on-metal bearing surface reduces the risk of dislocation, increases the range of movement, minimises the risk of impingement and, in theory, results in little wear.

Between February 2004 and March 2007 we implanted 100 consecutive total hip replacements with a metal-on-metal bearing and a large femoral head into 92 patients. There were 51 men and 41 women with a mean age of 50 years (18 to 70) at the time of surgery.

Outcome was assessed using the Western Ontario McMaster University osteoarthritis index and the Harris hip score as well as the Devane activity score. These all improved significantly (p < 0.0001). At the last follow-up there were no cases of dislocation, no impingement, a good range of movement and no osteolysis, but seven revisions, two for infection and five for aseptic loosening. The probability of groin pain increased if the other acetabular component inclination exceeded 50° (p = 0.0007). At 4.8 years of follow-up, the projected survival of the Durom acetabular component, with revision for any reason, was 92.4% (sd 2.8) (95% confidence interval 89.6 to 95.2).

The design of the component made it difficult both to orientate and seat, which when combined with a poor porous coating, produced unpredictable fixation and a low survival at five years.

This study evaluated the effect on movement under load of three different techniques for re-attachment of the tuberosities of the humerus using test sawbones. In the first, the tuberosities were attached both to the shaft and to each other, with one cerclage suture through the anterior hole in the prosthesis. The second technique was identical except for omission of the cerclage suture and in the third the tuberosities were attached to the prosthesis and to the shaft. An orthogonal photogrammetric system allowed all segments to be tracked in a 3D axis system. The humeri were incrementally-loaded in abduction, and the 3D linear and angular movements of all segments were calculated. Displacement between the tuberosities and the shaft was measured.

The first and second techniques were the most stable constructs, with the third allowing greater separation of fragments and angular movement. Separation at the midpoint of the tuberosities was significantly greater using the latter technique (p < 0.05). The cerclage suture added no further stability to the fixation.

Bone loss involving articular surface is a challenging problem faced by the orthopaedic surgeon. In the hand and wrist, there are articular defects that are amenable to autograft reconstruction when primary fixation is not possible. In this article, the surgical techniques and clinical outcomes of articular reconstructions in the hand and wrist using non-vascularised osteochondral autografts are reviewed.

A total of 445 consecutive primary total knee replacements (TKRs) were followed up prospectively at six and 18 months and three, six and nine years. Patients were divided into two groups: non-obese (body mass index (BMI) < 30 kg/m²) and obese (BMI ≥ 30 kg/m²). The obese group was subdivided into mildly obese (BMI 30 to 35 kg/m²) and highly obese (BMI ≥ 35 kg/m²) in order to determine the effects of increasing obesity on outcome. The clinical data analysed included the Knee Society score, peri-operative complications and implant survival. There was no difference in the overall complication rates or implant survival between the two groups.

Obesity appears to have a small but significant adverse effect on clinical outcome, with highly obese patients showing lower function scores than non-obese patients. However, significant improvements in outcome are sustained in all groups nine years after TKR. Given the substantial, sustainable relief of symptoms after TKR and the low peri-operative complication and revision rates in these two groups, we have found no reason to limit access to TKR in obese patients.

Twenty patients underwent simultaneous bilateral medial unicompartmental knee arthroplasty. Pre-operative hip-knee-ankle alignment and valgus stress radiographs were used to plan the desired post-operative alignment of the limb in accordance with established principles for unicompartmental arthroplasty. In each patient the planned alignment was the same for both knees. Overall, the mean planned post-operative alignment was to 2.3° of varus (0° to 5°).

The side and starting order of surgery were randomised, using conventional instrumentation for one knee and computer-assisted surgery for the opposite side.

The mean variation between the pre-operative plan and the achieved correction in the navigated and the non-navigated limb was 0.9° (sd 1.1; 0° to 4°) and 2.8° (sd 1.4; 1° to 7°), respectively. Using the Wilcoxon signed rank test, we found the difference in variation statistically significant (p < 0.001).

Assessment of lower limb alignment in the non-navigated group revealed that 12 (60%) were within ± 2° of the pre-operative plan, compared to 17 (87%) of the navigated cases.

Computer-assisted surgery significantly improves the post-operative alignment of medial unicompartmental knee arthroplasty compared to conventional techniques in patients undergoing bilateral simultaneous arthroplasty. Improved alignment after arthroplasty is associated with better function and increased longevity.

We report our early experience with the use of a non-invasive distal femoral expandable endoprosthesis in seven skeletally immature patients with osteosarcoma of the distal femur. The patients had a mean age of 12.1 years (9 to 15) at the time of surgery. The prosthesis was lengthened at appropriate intervals in outpatient clinics, without anaesthesia, using the principle of electromagnetic induction. The patients were functionally evaluated using the Musculoskeletal Tumour Society scoring system. The mean follow-up was 20.2 months (14 to 30). The prostheses were lengthened by a mean of 25 mm (4.25 to 55) and maintained a mean knee flexion of 110° (100° to 120°). The mean Musculoskeletal Tumour Society score was 68% (11 to 29). Complications developed in two patients; one developed a flexion deformity of 25° at the knee joint, which was subsequently overcome and one died of disseminated disease. The early results from patients treated with this device have been encouraging. The implant avoids multiple surgical procedures, general anaesthesia and assists in maintaining leg-length equality.

In order to assess current opinions on the long-term outcome after primary total hip replacement, we performed a multicentre, cross-sectional survey in 22 centres from 12 European countries. Different patient characteristics were categorised into ‘decreases chances’, ‘does not affect chances’, and ‘increases chances’ of a favourable long-term outcome, by 304 orthopaedic surgeons and 314 referring practitioners. The latter were less likely to associate age older than 80 years and obesity with a favourable outcome than orthopaedic surgeons (p < 0.001 and p = 0.006, respectively) and more likely to associate age younger than 50 years with a favourable outcome (p = 0.006). Comorbidity, rheumatoid arthritis, and poor bone quality were thought to be associated with a decreased chance of a favourable outcome. We found important differences in the opinions regarding long-term outcome after total hip replacement within and between referring practitioners and orthopaedic surgeons. These are likely to affect access to and the provision of total hip replacement.

The April 2012 Shoulder & Elbow Roundup³⁶⁰ looks at katakori in Japan, frozen shoulder, if shoulder impingement actually exists, shoulder arthroscopy and suprascapular nerve blocks, why shoulder replacements fail, the infected elbow replacement, the four-part fracture, the acromion index, and arm transplantation

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.

Post-operative complications after total hip or knee replacement can delay recovery, prolong hospitalisation, increase rates of re-admission and, in the most severe cases, lead to long-term disability or even death. In this analysis of pooled data from four large, randomised, phase III clinical trials that compared the oral, direct Factor Xa inhibitor rivaroxaban with subcutaneous enoxaparin for the prevention of venous thromboembolism after total hip or knee replacement (n = 12 729), the incidence of complications, including bleeding and adverse events related to surgery (such as wound infection, wound dehiscence and haemarthrosis) are reported. Interventions and procedures relating to surgery are also compared between the groups. Bleeding events, including excessive wound haematoma and surgical-site bleeding, occurred at similar rates in the rivaroxaban and enoxaparin groups. Over the total study duration, adverse surgical events occurred at a similar rate in the rivaroxaban group compared with the enoxaparin group after total knee replacement (2.26% vs 2.69%, respectively) and total hip replacement (1.48% vs 1.65%, respectively). Blood loss, wound drainage and transfusion requirements were also similar between the two groups.

This analysis shows that the incidence of adverse surgical events with rivaroxaban was similar to enoxaparin.

We present the results of ankle fusion using the Ilizarov technique for bone loss around the ankle in 20 patients. All except one had sustained post-traumatic bone loss. Infection was present in 17. The mean age was 33.1 years (7 to 71). The mean size of the defect was 3.98 cm (1.5 to 12) and associated limb shortening before the index procedure varied from 1 cm to 5 cm. The mean time in the external fixator was 335 days (42 to 870). Tibiotalar fusion was performed in 19 patients and tibiocalcaneal fusion in one. Associated problems included diabetes in one patient, pelvic and urethral injury in one, visual injury in one patient and ipsilateral tibial fracture in five. At the final mean follow-up of 51.55 months (24 to 121) fusion had been achieved in 19 of 20 patients. A total of 16 patients were able to return to work. The results were graded as good in 11 patients, fair in six and poor in three. The mean external fixation index was 8.8 days/mm (0 to 30). One patient with diabetes developed severe infection which required early removal of the fixator. Refractures occurred in three patients, two of which were at the site of fusion and one at a previous tibial shaft fracture site. Equinus deformity of the ankle fusion occurred after a further fracture in one patient. There were two patients with residual forefoot equinus, and one developed late valgus at the fusion site.

Poor consolidation of the regenerated bone in two patients was treated by bone grafting in one and by bone and fibular strut grafting in the other. Residual soft-tissue infection was still present in two patients.

We retrospectively reviewed 30 two-stage revision procedures in 28 patients performed for fungal peri-prosthetic joint infection (PJI) after a primary total knee replacement. Patients were followed for at least two years or until the infection recurred. The mean follow-up for patients who remained free of infection was 4.3 years (2.3 to 6.1). Overall, 17 patients were assessed as American Society of Anesthesiologists grade 3 or 4. The surgical protocol included removal of the infected implant, vigorous debridement and insertion of an articulating cement spacer. This was followed by at least six weeks of antimicrobial treatment and delayed reimplantation in all patients. The mean interval between removal of the prosthesis and reimplantation was 9.5 weeks (6 to 24). After reimplantation, patients took antifungal agents orally for a maximum of six months. Two knees became reinfected at one and two months post-operatively, respectively: one of these subsequently required arthrodesis because of uncontrolled infection.

Fungal PJIs can be treated successfully by removal of all infected material, appropriate antimicrobial treatment and delayed reimplantation.