Osteoarthritis is extremely common and many different causes for it have been described. One such cause is abnormal morphology of the affected joint, the hip being a good example of this. For those joints with femoroacetabular impingement (FAI) or developmental dysplasia of the hip (DDH), a link with subsequent osteoarthritis seems clear. However, far from being abnormal, these variants may be explained by evolution, certainly so for FAI, and may actually be normal rather than representing deformity or disease. The animal equivalent of FAI is coxa recta, commonly found in species that run and jump. It is rarely found in animals that climb and swim. In contrast are the animals with coxa rotunda, a perfectly spherical femoral head, and more in keeping with the coxa profunda of mankind. This article describes the evolutionary process of the human hip and its link to FAI and DDH. Do we need to worry after all?

We investigated the incidence and risk factors for the development of avascular necrosis (AVN) of the femoral head in the course of treatment of children with cerebral palsy (CP) and dislocation of the hip. All underwent open reduction, proximal femoral and Dega pelvic osteotomy. The inclusion criteria were: a predominantly spastic form of CP, dislocation of the hip (migration percentage, MP > 80%), Gross Motor Function Classification System, (GMFCS) grade IV to V, a primary surgical procedure and follow-up of > one year.

There were 81 consecutive children (40 girls and 41 boys) in the study. Their mean age was nine years (3.5 to 13.8) and mean follow-up was 5.5 years (1.6 to 15.1). Radiological evaluation included measurement of the MP, the acetabular index (AI), the epiphyseal shaft angle (ESA) and the pelvic femoral angle (PFA). The presence and grade of AVN were assessed radiologically according to the Kruczynski classification.

Signs of AVN (grades I to V) were seen in 79 hips (68.7%). A total of 23 hips (18%) were classified between grades III and V.

Although open reduction of the hip combined with femoral and Dega osteotomy is an effective form of treatment for children with CP and dislocation of the hip, there were signs of avascular necrosis in about two-thirds of the children. There was a strong correlation between post-operative pain and the severity of the grade of AVN.

Cite this article: Bone Joint J 2015;97-B:270–6.

We undertook a retrospective comparative study of all patients with an unstable slipped capital femoral epiphysis presenting to a single centre between 1998 and 2011. There were 45 patients (46 hips; mean age 12.6 years; 9 to 14); 16 hips underwent intracapsular cuneiform osteotomy and 30 underwent pinning in situ, with varying degrees of serendipitous reduction. No patient in the osteotomy group was lost to follow-up, which was undertaken at a mean of 28 months (11 to 48); four patients in the pinning in situ group were lost to follow-up, which occurred at a mean of 30 months (10 to 50). Avascular necrosis (AVN) occurred in four hips (25%) following osteotomy and in 11 (42%) following pinning in situ. AVN was not seen in five hips for which osteotomy was undertaken > 13 days after presentation. AVN occurred in four of ten (40%) hips undergoing emergency pinning in situ, compared with four of 15 (47%) undergoing non-emergency pinning. The rate of AVN was 67% (four of six) in those undergoing pinning on the second or third day after presentation.

Pinning in situ following complete reduction led to AVN in four out of five cases (80%). In comparison, pinning in situ following incomplete reduction led to AVN in 7 of 21 cases (33%). The rate of development of AVN was significantly higher following pinning in situ with complete reduction than following intracapsular osteotomy (p = 0.048). Complete reduction was more frequent in those treated by emergency pinning and was strongly associated with AVN (p = 0.005).

Non-emergency intracapsular osteotomy may have a protective effect on the epiphyseal vasculature and should be undertaken with a delay of at least two weeks. The place of emergency pinning in situ in these patients needs to be re-evaluated, possibly in favour of an emergency open procedure or delayed intracapsular osteotomy. Non-emergency pinning in situ should be undertaken after a delay of at least five days, with the greatest risk at two and three days after presentation. Intracapsular osteotomy should be undertaken after a delay of at least 14 days. In our experience, closed epiphyseal reduction is harmful.

Cite this article: Bone Joint J 2015;97-B:412–19.

Conventional cemented acetabular components are reported to have a high rate of failure when implanted into previously irradiated bone. We recommend the use of a cemented reconstruction with the addition of an acetabular reinforcement cross to improve fixation.

We reviewed a cohort of 45 patients (49 hips) who had undergone irradiation of the pelvis and a cemented total hip arthroplasty (THA) with an acetabular reinforcement cross. All hips had received a minimum dose of 30 Gray (Gy) to treat a primary nearby tumour or metastasis. The median dose of radiation was 50 Gy (Q1 to Q3: 45 to 60; mean: 49.57, 32 to 72).

The mean follow-up after THA was 51 months (17 to 137). The cumulative probability of revision of the acetabular component for a mechanical reason was 0% (0 to 0%) at 24 months, 2.9% (0.2 to 13.3%) at 60 months and 2.9% (0.2% to 13.3%) at 120 months, respectively. One hip was revised for mechanical failure and three for infection.

Cemented acetabular components with a reinforcement cross provide good medium-term fixation after pelvic irradiation. These patients are at a higher risk of developing infection of their THA.

Cite this article: Bone Joint J 2015;97-B:177–84.

Intact abductors of the hip play a crucial role in preventing limping and are known to be damaged through the direct lateral approach. The extent of trauma to the abductors after revision total hip replacement (THR) is unknown. The aim of this prospective study was to compare the pre- and post-operative status of the gluteus medius muscle after revision THR. We prospectively compared changes in the muscle and limping in 30 patients who were awaiting aseptic revision THR and 15 patients undergoing primary THR. The direct lateral approach as described by Hardinge was used for all patients. MRI scans of the gluteus medius and functional analyses were recorded pre-operatively and six months post-operatively. The overall mean fatty degeneration of the gluteus medius increased from 35.8% (1.1 to 98.8) pre-operatively to 41% (1.5 to 99.8) after multiple revision THRs (p = 0.03). There was a similar pattern after primary THR, but with considerably less muscle damage (p = 0.001), indicating progressive muscle damage. Despite an increased incidence of a positive Trendelenburg sign following revision surgery (p = 0.03) there was no relationship between the cumulative fatty degeneration in the gluteus medius and a positive Trendelenburg sign (p = 0.26). The changes associated with other surgical approaches to the hip warrant investigation.

Cite this article: Bone Joint J 2014;96-B:1618–22.

The outcomes of 261 nerve injuries in 100 patients were graded good in 173 cases (66%), fair in 70 (26.8%) and poor in 18 (6.9%) at the final review (median 28.4 months (1.3 to 64.2)). The initial grades for the 42 sutures and graft were 11 good, 14 fair and 17 poor. After subsequent revision repairs in seven, neurolyses in 11 and free vascularised fasciocutaneous flaps in 11, the final grades were 15 good, 18 fair and nine poor. Pain was relieved in 30 of 36 patients by nerve repair, revision of repair or neurolysis, and flaps when indicated. The difference in outcome between penetrating missile wounds and those caused by explosions was not statistically significant; in the latter group the onset of recovery from focal conduction block was delayed (mean 4.7 months (2.5 to 10.2) vs 3.8 months (0.6 to 6); p = 0.0001). A total of 42 patients (47 lower limbs) presented with an insensate foot. By final review (mean 27.4 months (20 to 36)) plantar sensation was good in 26 limbs (55%), fair in 16 (34%) and poor in five (11%). Nine patients returned to full military duties, 18 to restricted duties, 30 to sedentary work, and 43 were discharged from military service. Effective rehabilitation must be early, integrated and vigorous. The responsible surgeons must be firmly embedded in the process, at times exerting leadership.

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.

The aim of this study was to evaluate the functional and oncological outcome of extracorporeally irradiated autografts used to reconstruct the pelvis after a P1/2 internal hemipelvectomy.

The study included 18 patients with a primary malignant bone tumour of the pelvis. There were 13 males and five females with a mean age of 24.8 years (8 to 62). Of these, seven had an osteogenic sarcoma, six a Ewing’s sarcoma, and five a chondrosarcoma. At a mean follow-up of 51.6 months (4 to 185), nine patients had died with metastatic disease while nine were free from disease. Local recurrence occurred in three patients all of whom eventually died of their disease. Deep infection occurred in three patients and required removal of their graft in two while the third underwent a hindquarter amputation for extensive flap necrosis.

The mean Musculoskeletal Tumor Society functional score of the 16 patients who could be followed-up for at least 12 months was 77% (50 to 90). Those 15 patients who completed the Toronto Extremity Salvage Score questionnaire had a mean score of 71% (53 to 85).

Extracorporeal irradiation and re-implantation of bone is a valid method of reconstruction after an internal hemipelvectomy. It has an acceptable morbidity and a functional outcome that compares favourably with other available reconstructive techniques.

Cite this article: Bone Joint J 2014;96-B:1404–10

Objectives

Acetabular retractors have been implicated in damage to the femoral and obturator nerves during total hip replacement. The aim of this study was to determine the anatomical relationship between retractor placement and these nerves.

Resection of malignant bony tumours of the pelvis creates large bone and soft-tissue defects, and is frequently associated with complications such as wound dehiscence and deep infection. We present the results of six patients in whom a rectus abdominis myocutaneous (RAM) flap was used following resection of a malignant tumour of the pelvis. Bony reconstruction was performed using a constrained hip tumour prosthesis in three patients, vascularised fibular graft in two and frozen autograft in one. At a mean follow-up of 63 months (16 to 115), no patients had a problem with the wound.

Immediate reconstruction using a RAM flap may be used after resection of a malignant tumour of the pelvis to provide an adequate volume of tissue to eliminate the dead space, cover the exposed bone or implants with well-vascularised soft tissue and to reduce the risk of complications.

Cite this article: Bone Joint J 2014;96-B:270–3.

We conducted a retrospective study to assess the prevalence of adverse reactions to metal debris (ARMD) in patients operated on at our institution with metal-on-metal (MoM) total hip replacements with 36 mm heads using a Pinnacle acetabular shell. A total of 326 patients (150 males, 175 hips; 176 females, 203 hips) with a mean age of 62.7 years (28 to 85) and mean follow-up of 7.5 years (0.1 to 10.8) participating in our in-depth modern MoM follow-up programme were included in the study, which involved recording whole blood cobalt and chromium ion measurements, Oxford hip scores (OHS) and plain radiographs of the hip and targeted cross-sectional imaging. Elevated blood metal ion levels (> 5 parts per billion) were seen in 32 (16.1%) of the 199 patients who underwent unilateral replacement. At 23 months after the start of our modern MoM follow-up programme, 29 new cases of ARMD had been revealed. Hence, the nine-year survival of this cohort declined from 96% (95% CI 95 to 98) with the old surveillance routine to 86% (95% CI 82 to 90) following the new protocol. Although ARMD may not be as common in 36 mm MoM THRs as in those with larger heads, these results support the Medicines and Healthcare Products Regulatory Agency guidelines on regular reviews and further investigations, and emphasise the need for specific a follow-up programme for patients with MoM THRs.

Cite this article: Bone Joint J 2014; 96-B:1610–17.

We describe a new technique of reconstruction of the deficient acetabulum in cementless total hip arthroplasty. The outer iliac table just above the deficient acetabulum is osteotomised and slid downwards. We have termed this an iliac sliding graft. Between October 1997 and November 2001, cementless total hip arthroplasty with an iliac sliding graft was performed on 19 patients (19 hips) with acetabular dysplasia. The mean follow-up was 3.4 years (2 to 6).

The mean pre-operative Harris hip score was 45.1 which improved significantly to 85.3 at the time of the final follow-up. No patient had post-operative abductor dysfunction. Incorporation of the graft was seen after two to three months in all patients. Resorption of the graft and radiolucencies were infrequent. This technique is a useful alternative to femoral head autografting when the patient’s own femoral head cannot be used.

Bone sarcomas are rare cancers and orthopaedic surgeons come across them infrequently, sometimes unexpectedly during surgical procedures. We investigated the outcomes of patients who underwent a surgical procedure where sarcomas were found unexpectedly and were subsequently referred to our unit for treatment. We identified 95 patients (44 intra-lesional excisions, 35 fracture fixations, 16 joint replacements) with mean age of 48 years (11 to 83); 60% were males (n = 57). Local recurrence arose in 40% who underwent limb salvage surgery versus 12% who had an amputation. Despite achieving local control, overall survival was worse for patients treated with amputation rather than limb salvage (54% vs 75% five-year survival). Factors that negatively influenced survival were invasive primary surgery (fracture fixation, joint replacement), a delay of greater than two months until referral to our oncology service, and high-grade tumours. Survival in these circumstances depends mostly on factors that are determined prior to definitive treatment by a tertiary orthopaedic oncology unit. Limb salvage in this group of patients is associated with a higher rate of inadequate marginal surgery and, consequently, higher local recurrence rates than amputation, but should still be attempted whenever possible, as local control is not the primary determinant of survival.

Cite this article: Bone Joint J 2014;96-B:665–72.

We report our experience of revision total hip replacement (THR) using the Revitan curved modular titanium fluted revision stem in patients with a full spectrum of proximal femoral defects. A total of 112 patients (116 revisions) with a mean age of 73.4 years (39 to 90) were included in the study. The mean follow-up was 7.5 years (5.3 to 9.1). A total of 12 patients (12 hips) died but their data were included in the survival analysis, and four patients (4 hips) were lost to follow-up. The clinical outcome, proximal bone regeneration and subsidence were assessed for 101 hips.

The mean Harris Hip Score was 88.2 (45.8 to 100) after five years and there was an increase of the mean Barnett and Nordin-Score, a measure of the proximal bone regeneration, of 20.8 (-3.1 to 52.7). Five stems had to be revised (4.3%), three (2.9%) showed subsidence, five (4.3%) a dislocation and two of 85 aseptic revisions (2.3%) a periprosthetic infection.

At the latest follow-up, the survival with revision of the stem as the endpoint was 95.7% (95% confidence interval 91.9% to 99.4%) and with aseptic loosening as the endpoint, was 100%. Peri-prosthetic fractures were not observed.

We report excellent results with respect to subsidence, the risk of fracture, and loosening after femoral revision using a modular curved revision stem with distal cone-in-cone fixation. A successful outcome depends on careful pre-operative planning and the use of a transfemoral approach when the anatomy is distorted or a fracture is imminent, or residual cement or a partially-secured existing stem cannot be removed. The shortest appropriate stem should, in our opinion, be used and secured with > 3 cm fixation at the femoral isthmus, and distal interlocking screws should be used for additional stability when this goal cannot be realised.

Cite this article: Bone Joint J 2014;96-B:889–95.

The February 2014 Hip & Pelvis Roundup³⁶⁰ looks at: length of stay; cementless metaphyseal fixation; mortality trends in over 400,000 total hip replacements; antibiotics in hip fracture surgery; blood supply to the femoral head after dislocation; resurfacing and THR in metal-on-metal replacement; diabetes and hip replacement; bone remodelling over two decades following hip replacement; and whether bisphosphonates affect acetabular fixation.

Hip replacement is a very successful operation and the outcome is usually excellent. There are recognised complications that seem increasingly to give rise to litigation. This paper briefly examines some common scenarios where litigation may be pursued against hip surgeons. With appropriate record keeping, consenting and surgical care, the claim can be successfully defended if not avoided. We hope this short summary will help to highlight some common pitfalls. There is extensive literature available for detailed study.

Patients with acetabular dysplasia commonly undergo peri-acetabular osteotomy after skeletal maturity to reduce the risk of the late development of osteoarthritis. Several studies have suggested that deformity of the femoral head influences the long-term outcome. We radiologically examined 224 hips in 112 patients with acetabular dysplasia and early-stage osteoarthritis. There were 103 women and nine men with a mean age of 37.6 years (18 to 49). A total of 201 hips were placed in the acetabular dysplasia group and 23 in a normal group. The centre–edge angle and acetabular head index were significantly smaller (both p < 0.001), and the acetabular angle, acetabular roof angle and roundness index were significantly greater in the acetabular dysplasia group than those in the normal group (all p < 0.001). There were significant correlations between the roundness index and other parameters. Femoral head shape may be influenced by the severity of the acetabular dysplasia.

Cite this article: Bone Joint J 2013;95-B:1192–6.

We describe the technique and results of medial submuscular plating of the femur in paediatric patients and discuss its indications and limitations. Specifically, the technique is used as part of a plate-after-lengthening strategy, where the period of external fixation is reduced and the plate introduced by avoiding direct contact with the lateral entry wounds of the external fixator pins. The technique emphasises that vastus medialis is interposed between the plate and the vascular structures.

A total of 16 patients (11 male and five female, mean age 9.6 years (5 to 17)), had medial submuscular plating of the femur. All underwent distraction osteogenesis of the femur with a mean lengthening of 4.99 cm (3.2 to 12) prior to plating. All patients achieved consolidation of the regenerate without deformity. The mean follow-up was 10.5 months (7 to 15) after plating for those with plates still in situ, and 16.3 months (1 to 39) for those who subsequently had their plates removed. None developed a deep infection. In two patients a proximal screw fractured without loss of alignment; one patient sustained a traumatic fracture six months after removal of the plate.

Placing the plate on the medial side is advantageous when the external fixator is present on the lateral side, and is biomechanically optimal in the presence of a femoral defect. We conclude that medial femoral submuscular plating is a useful technique for specific indications and can be performed safely with a prior understanding of the regional anatomy.

Cite this article: Bone Joint J 2014;96-B:137–42.

The October 2013 Hip & Pelvis Roundup³⁶⁰ looks at: Young and impinging; Clothes, weather and femoral heads?; Go long, go cemented; Surgical repair of the abductors?; Aspirin for DVT prophylaxis?; Ceramic-on-polyethylene: a low-wear solution?; ALVAL and ASR™: the story continues….; Salvaging Legg-Calve-Perthes’ disease