Aims

The primary aim of this study was to define and quantify three new measurements to indicate the position of the greater trochanter. Secondary aims were to define ‘functional antetorsion’ as it relates to abductor function in populations both with and without torsional abnormality.

We investigated the detailed anatomy of the gluteus maximus, gluteus medius and gluteus minimus and their neurovascular supply in 22 hips in 11 embalmed adult Caucasian human cadavers. This led to the development of a surgical technique for an extended posterior approach to the hip and pelvis that exposes the supra-acetabular ilium and preserves the glutei during revision hip surgery. Proximal to distal mobilisation of the gluteus medius from the posterior gluteal line permits exposure and mobilisation of the superior gluteal neurovascular bundle between the sciatic notch and the entrance to the gluteus medius, enabling a wider exposure of the supra-acetabular ilium. This technique was subsequently used in nine patients undergoing revision total hip replacement involving the reconstruction of nine Paprosky 3B acetabular defects, five of which had pelvic discontinuity. Intra-operative electromyography showed that the innervation of the gluteal muscles was not affected by surgery. Clinical follow-up demonstrated good hip abduction function in all patients. These results were compared with those of a matched cohort treated through a Kocher–Langenbeck approach. Our modified approach maximises the exposure of the ilium above the sciatic notch while protecting the gluteal muscles and their neurovascular bundle.

Cite this article: Bone Joint J 2014;96-B:48–53.

Introduction. Gluteus medius is disrupted during lateral approach total hip arthroplasty (THA) which may impact its function and ability to control the pelvis. The objective was to compare gluteus medius activation and joint mechanics associated with a Trendelenburg sign (pelvic drop, trunk lean) during gait and hip abductor strength between patients that underwent lateral or posterior THA approaches one year post-surgery and healthy adults. Methods. Participants that underwent primary THA for hip osteoarthritis using lateral (n=21) or posterior (n=21) approaches, and healthy adults (n=21) were recruited for this cross-sectional study. Participants completed five walking trials. Surface electromyography captured gluteus medius activation. A 3-dimensional optical motion capture system measured frontal plane pelvic obliquity and lateral trunk lean angles. Participants performed maximum voluntary isometric contractions (MVIC) on a dynamometer to measure hip abductor torque. Characteristics from gait waveforms were identified using principal component analysis, and participant waveforms were scored against these characteristics to produce principal component scores. One-way analysis of variance and effect sizes (d) compared gait principal component scores and isometric hip abductor torque between groups. Results. Lateral THA group had statistically significant higher gluteus medius PC-scores indicating higher overall amplitudes during gait (p<0.01, d=0.97) and prolonged midstance activation (p=0.01, d=0.95) compared to the healthy group (Figure). There were no statistically significant (p>0.05) differences in pelvis or trunk angles. Isometric hip abductor torque was significantly (p=0.03, d=0.74) lower in the lateral THA than healthy group. There were no statistically significant differences between THA groups (d=0.27–0.50). Conclusions. Although the lateral THA group had lower abductor torque, there were no Trendelenburg signs during gait. Elevated gluteus medius activation in this group was a compensation for the weakness, and the muscle produced sufficient force to control the pelvis. Also, 1 year post-THA there were no statistically significant gait differences between lateral and posterior approaches. For any tables or figures, please contact the authors directly

Introduction. Femoroacetabular impingement (FAI) is a morphological hip joint deformity associated with pain and early degenerative changes. Cam-type FAI is prevalent in young male athletes. While biomechanical deficiencies (decreased hip muscle strength and range of motion (ROM)) have been associated with symptomatic cam-type FAI (sFAI), results have been conflicting and little is known about biomechanical characteristics during dynamic tasks. Objectives. (1) Compare coronal-plane hip muscle strength, activation and joint rotation during movement tasks in sFAI hips against healthy controls. (2) Investigate the effect of hip internal rotation ROM (IR-ROM) on these outcomes. Methods. 11 sFAI and 24 well-matched healthy control hips from 18 young adult male athletes were recruited (Table.1). Passive hip IR-ROM was measured with goniometry. Weight-normalised hip abductor and adductor isometric maximal voluntary contraction torques were quantified with handheld dynamometry. Gluteus medius and adductor longus activation and hip coronal-plane kinematics were collected with surface electromyography (EMG) and motion-capture during time-defined phases of sit-to-stand (Fig.1) and single-leg-squat (Fig.2) tasks. Effect of sFAI with hip IR-ROM as a separate independent variable was calculated with 1-way MANCOVA. Results. sFAI had significantly less IR-ROM (19.25°±5.94) than controls (28.83°±7.24) (p<0.001). During the sit-to-stand ascent phase, significantly more hip abduction (F=4.93, p=0.03) was observed in sFAI (13.06°±3.16) compared to controls (10.16°±3.72). With IR-ROM differences controlled for, significantly higher gluteus medius:adductor longus EMG activation ratio (F=4.32, p=0.046) was observed in the same phase in sFAI (0.16±0.34) compared to controls (−0.11±0.31). No other significant results were found. Conclusion. sFAI hips demonstrate altered muscle activation and movement patterns when ascending from seated positions compared to controls, with reduced hip IR-ROM in sFAI hips influencing findings. Abductor and adductor function imbalance may explain why sFAI increases risk of early degenerative changes. Despite study limitations (no imaging for sFAI diagnosis), these findings should be considered when optimising rehabilitation in this population. For any figures and tables, please contact the authors directly

Aims

The primary objective of this study was to develop a validated classification system for assessing iatrogenic bone trauma and soft-tissue injury during total hip arthroplasty (THA). The secondary objective was to compare macroscopic bone trauma and soft-tissues injury in conventional THA (CO THA) versus robotic arm-assisted THA (RO THA) using this classification system.

Aims

The gluteus minimus (GMin) and gluteus medius (GMed) have unique structural and functional segments that may be affected to varying degrees, by end-stage osteoarthritis (OA) and normal ageing. We used data from patients with end-stage OA and matched healthy controls to 1) quantify the atrophy of the GMin and GMed in the two groups and 2) describe the distinct patterns of the fatty infiltration in the different segments of the GMin and GMed in the two groups.

Aims

We wished to quantify the extent of soft-tissue damage sustained during minimally invasive total hip arthroplasty through the direct anterior (DA) and direct superior (DS) approaches.

Aims

The number of patients undergoing arthroscopic surgery of the hip has increased significantly during the past decade. It has now become an established technique for the treatment of many intra- and extra-articular conditions affecting the hip. However, it has a steep learning curve and is not without the risk of complications. The purpose of this systematic review was to determine the prevalence of complications during and following this procedure.

In this paper we propose a new classification of neurogenic peri-articular heterotopic ossification (HO) of the hip based on three-dimensional (3D) CT, with the aim of improving pre-operative planning for its excision.

A total of 55 patients (73 hips) with clinically significant HO after either traumatic brain or spinal cord injury were assessed by 3D-CT scanning, and the results compared with the intra-operative findings.

At operation, the gross pathological anatomy of the HO as identified by 3D-CT imaging was confirmed as affecting the peri-articular hip muscles to a greater or lesser extent. We identified seven patterns of involvement: four basic (anterior, medial, posterior and lateral) and three mixed (anteromedial, posterolateral and circumferential). Excellent intra- and inter-observer agreement, with kappa values > 0.8, confirmed the reproducibility of the classification system.

We describe the different surgical approaches used to excise the HO which were guided by the 3D-CT findings. Resection was always successful.

3D-CT imaging, complemented in some cases by angiography, allows the surgeon to define the 3D anatomy of the HO accurately and to plan its surgical excision with precision.

Cite this article: Bone Joint J 2015; 97-B:899–904.

The piriformis muscle is an important landmark in the surgical anatomy of the hip, particularly the posterior approach for total hip replacement (THR). Standard orthopaedic teaching dictates that the tendon must be cut in to allow adequate access to the superior part of the acetabulum and the femoral medullary canal. However, in our experience a routine THR can be performed through a posterior approach without sacrificing this tendon.

We dissected the proximal femora of 15 cadavers in order to clarify the morphological anatomy of the piriformis tendon. We confirmed that the tendon attaches on the crest of the greater trochanter, in a position superior to the trochanteric fossa, away from the entry point for broaching the intramedullary canal during THR. The tendon attachment site encompassed the summit and medial aspect of the greater trochanter as well as a variable attachment to the fibrous capsule of the hip joint. In addition we dissected seven cadavers resecting all posterior attachments except the piriformis muscle and tendon in order to study their relations to the hip joint, as the joint was flexed. At flexion of 90° the piriformis muscle lay directly posterior to the hip joint.

The piriform fossa is a term used by orthopaedic surgeons to refer the trochanteric fossa and normally has no relation to the attachment site of the piriformis tendon. In hip flexion the piriformis lies directly behind the hip joint and might reasonably be considered to contribute to the stability of the joint.

We conclude that the anatomy of the piriformis muscle is often inaccurately described in the current surgical literature and terms are used and interchanged inappropriately.

Cite this article: Bone Joint J 2013;95-B:764–9.

The direct anterior approach in total hip replacement anatomically offers the chance to minimise soft-tissue trauma because an intermuscular and internervous plane is explored. This motivated us to abandon our previously used transgluteal approach and to adopt the direct anterior approach for total hip replacement. Using MRI, we performed a retrospective comparative study of the direct anterior approach with the transgluteal approach. There were 25 patients in each group. At one year post-operatively all the patients underwent MRI of their replaced hips. A radiologist graded the changes in the soft-tissue signals in the abductor muscles. The groups were similar in terms of age, gender, body mass index, complexity of the reconstruction and absence of symptoms.

Detachment of the abductor insertion, partial tears and tendonitis of gluteus medius and minimus, the presence of peri-trochanteric bursal fluid and fatty atrophy of gluteus medius and minimus were significantly less pronounced and less frequent when the direct anterior approach was used. There was no significant difference in the findings regarding tensor fascia lata between the two approaches.

We conclude that use of the direct anterior approach results in a better soft-tissue response as assessed by MRI after total hip replacement. However, the impact on outcome needs to be evaluated further.

The aim of this review is to evaluate the current available literature evidencing on peri-articular hip endoscopy (the third compartment). A comprehensive approach has been set on reports dealing with endoscopic surgery for recalcitrant trochanteric bursitis, snapping hip (or coxa-saltans; external and internal), gluteus medius and minimus tears and endoscopy (or arthroscopy) after total hip arthroplasty. This information can be used to trigger further research, innovation and education in extra-articular hip endoscopy.

In patients with severe quadriplegic cerebral palsy and painful hip dislocation proximal femoral resection arthroplasty can reduce pain, but the risk of heterotopic ossification is significant. We present a surgical technique of autologous capping of the femoral stump in order to reduce this risk, using the resected femoral head as the graft.

A retrospective study of 31 patients (43 hips) who had undergone proximal femoral resection arthroplasty with (29 hips) and without autologous capping (14 hips) was undertaken. Heterotopic ossification was less frequent in patients with autologous capping, and a more predictable pattern of bony overgrowth was found.

For a selected group of non-ambulatory patients with long-standing painful dislocation of the hip, we recommend femoral resection arthroplasty over more complicated reconstructive operations. The risk of heterotopic ossification, which is a major disadvantage of this operation, is reduced by autologous capping.

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 treated 26 hips (24 consecutive patients) with residual dysplasia by a technique of incomplete triple pelvic osteotomy. The mean age of the patients was 21.6 years.

The mean values for the pre-operative centre-edge angle of Wiberg, the refined centre-edge angle, the acetabular angle of Sharp, the modified acetabular angle and femoral head lateralisation were 7.7°, −3.1°, 49.3°, 53.2° and 17.2 mm, respectively. After a mean follow-up of 3.3 years they were 27.0°, 13.0°, 38.9°, 44.3° and 15.9 mm, respectively (p < 0.05). The osteoarthritic grading changed adversely in one hip. The mean pre-operative and latest Harris hip scores were 74.9 and 93.0, respectively (p < 0.05).

This technique provides a stable osteotomy with maintenance of the posterior column which allows early mobilisation and minimal internal fixation. The technique is not complex and requires minimal blood transfusion. The use of an image intensifier is not necessary and harvesting of a subcristal bone graft avoids post-operative complications at the donor site.