The April 2013 Hip & Pelvis Roundup³⁶⁰ looks at: hip cartilage and magnets; labral repair or resection; who benefits from injection; rotational osteotomy for osteonecrosis; whether ceramic implants risk fracture; dual articulation; and hydroxyapatite.

Aim

Until now, there has been no consensus as to whether stemmed acetabular components are appropriate for use in patients undergoing revision total hip arthroplasty (THA) who have major acetabular defects or pelvic discontinuity. We wished to address this deficiency in the literature.

This review examines the future of total hip arthroplasty, aiming to avoid past mistakes

Objective

This study compared the primary stability of two commercially available acetabular components from the same manufacturer, which differ only in geometry; a hemispherical and a peripherally enhanced design (peripheral self-locking (PSL)). The objective was to determine whether altered geometry resulted in better primary stability.

We undertook a randomised controlled trial to compare bipolar hemiarthroplasty (HA) with a novel total hip replacement (THR) comprising a polycarbonate–urethane (PCU) acetabular component coupled with a large-diameter metal femoral head for the treatment of displaced fractures of the femoral neck in elderly patients. Functional outcome, assessed with the Harris hip score (HHS) at three months and then annually after surgery, was the primary endpoint. Rates of revision and complication were secondary endpoints.

Based on a power analysis, 96 consecutive patients aged > 70 years were randomised to receive either HA (49) or a PCU-THR (47). The mean follow-up was 30.1 months (23 to 50) and 28.6 months (22 to 52) for the HA and the PCU group, respectively.

The HHS showed no statistically significant difference between the groups at every follow-up. Higher pain was recorded in the PCU group at one and two years’ follow-up (p = 0.006 and p = 0.019, respectively). In the HA group no revision was performed. In the PCU-THR group six patients underwent revision and one patient is currently awaiting re-operation. The three-year survival rate of the PCU-THR group was 0.841 (95% confidence interval 0.680 to 0.926).

Based on our findings we do not recommend the use of the PCU acetabular component as part of the treatment of patients with fractures of the femoral neck.

Cite this article: Bone Joint J 2013;95-B:609–15.

Metal-on-metal hip arthroplasty gained significant favor in the first decade of the millennium. However, the past several years have seen increasing reports of failure, pseudotumor and other adverse reactions. This study presents the results of a single center’s 15-year experience with metal-on-metal total hip arthroplasty as strong evidence that metal-on-metal is going, going, gone.

Objectives

Wear debris released from bearing surfaces has been shown to provoke negative immune responses in the recipient. Excessive wear has been linked to early failure of prostheses. Analysis using coordinate measuring machines (CMMs) can provide estimates of total volumetric material loss of explanted prostheses and can help to understand device failure. The accuracy of volumetric testing has been debated, with some investigators stating that only protocols involving hundreds of thousands of measurement points are sufficient. We looked to examine this assumption and to apply the findings to the clinical arena.

Aims

We report on the outcome of the Exeter Contemporary flanged cemented all-polyethylene acetabular component with a mean follow-up of 12 years (10 to 13.9). This study reviewed 203 hips in 194 patients. 129 hips in 122 patients are still in situ; 66 hips in 64 patients were in patients who died before ten years, and eight hips (eight patients) were revised. Clinical outcome scores were available for 108 hips (104 patients) and radiographs for 103 hips (100 patients).

Trabecular metal (TM) augments are a relatively new option for reconstructing segmental bone loss during acetabular revision. We studied 34 failed hip replacements in 34 patients that were revised between October 2003 and March 2010 using a TM acetabular shell and one or two augments. The mean age of the patients at the time of surgery was 69.3 years (46 to 86) and the mean follow-up was 64.5 months (27 to 107). In all, 18 patients had a minor column defect, 14 had a major column defect, and two were associated with pelvic discontinuity. The hip centre of rotation was restored in 27 patients (79.4%). The Oxford hip score increased from a mean of 15.4 points (6 to 25) before revision to a mean of 37.7 (29 to 47) at the final follow-up. There were three aseptic loosenings of the construct, two of them in the patients with pelvic discontinuity. One septic loosening also occurred in a patient who had previously had an infected hip replacement. The augments remained stable in two of the failed hips. Whenever there was a loose acetabular component in contact with a stable augment, progressive metal debris shedding was evident on the serial radiographs. Complications included another deep infection treated without revision surgery. Good clinical and radiological results can be expected for bone-deficient acetabula treated by a TM cup and augment, but for pelvic discontinuities this might not be a reliable option.

Cite this article: Bone Joint J 2013;95-B:166–72.

Aims

The primary aim of this study was to analyse the position of the acetabular and femoral components in total hip arthroplasty undertaken using an anterior surgical approach.

Aims

The long-term functional outcome of total hip arthroplasty (THA) performed by trainees is not known. A multicentre retrospective study of 879 THAs was undertaken to investigate any differences in outcome between those performed by trainee surgeons and consultants.

Objectives

Our study aimed to examine not only the incidence but also the impact of noise from two types of total hip replacement articulations: ceramic-on-ceramic and ceramic-on-polyethylene.

We reviewed the literature on the currently available choices of bearing surface in total hip replacement (THR). We present a detailed description of the properties of articulating surfaces review the understanding of the advantages and disadvantages of existing bearing couples. Recent technological developments in the field of polyethylene and ceramics have altered the risk of fracture and the rate of wear, although the use of metal-on-metal bearings has largely fallen out of favour, owing to concerns about reactions to metal debris. As expected, all bearing surface combinations have advantages and disadvantages. A patient-based approach is recommended, balancing the risks of different options against an individual’s functional demands.

Cite this article: Bone Joint J 2014;96-B:147–56.

We report the use of a 15° face-changing cementless acetabular component in patients undergoing total hip replacement for osteoarthritis secondary to developmental dysplasia of the hip. The rationale behind its design and the surgical technique used for its implantation are described. It is distinctly different from a standard cementless hemispherical component as it is designed to position the bearing surface at the optimal angle of inclination, that is, < 45°, while maximising the cover of the component by host bone.

Given the increasing number of total hip arthroplasty procedures being performed annually, it is imperative that orthopaedic surgeons understand factors responsible for instability. In order to treat this potentially complex problem, we recommend correctly classifying the type of instability present based on component position, abductor function, impingement, and polyethylene wear. Correct classification allows the treating surgeon to choose the appropriate revision option that ultimately will allow for the best potential outcome.

Cite this article: Bone Joint J 2016;98-B(1 Suppl A):44–9.

Aims

The optimal management of intracapsular fractures of the femoral neck in independently mobile patients remains open to debate. Successful fixation obviates the limitations of arthroplasty for this group of patients. However, with fixation failure rates as high as 30%, the outcome of revision surgery to salvage total hip arthroplasty (THA) must be considered. We carried out a systematic review to compare the outcomes of salvage THA and primary THA for intracapsular fractures of the femoral neck.

The painful subluxed or dislocated hip in adults with cerebral palsy presents a challenging problem. Prosthetic dislocation and heterotopic ossification are particular concerns. We present the first reported series of 19 such patients (20 hips) treated with hip resurfacing and proximal femoral osteotomy. The pre-operative Gross Motor Function Classification System (GMFCS) was level V in 13 (68%) patients, level IV in three (16%), level III in one (5%) and level II in two (11%). The mean age at operation was 37 years (13 to 57).

The mean follow-up was 8.0 years (2.7 to 11.6), and 16 of the 18 (89%) contactable patients or their carers felt that the surgery had been worthwhile. Pain was relieved in 16 of the 18 surviving hips (89%) at the last follow-up, and the GMFCS level had improved in seven (37%) patients. There were two (10%) early dislocations; three hips (15%) required revision of femoral fixation, and two hips (10%) required revision, for late traumatic fracture of the femoral neck and extra-articular impingement, respectively. Hence there were significant surgical complications in a total of seven hips (35%). No hips required revision for instability, and there were no cases of heterotopic ossification.

We recommend hip resurfacing with proximal femoral osteotomy for the treatment of the painful subluxed or dislocated hip in patients with cerebral palsy.

We have studied the natural history of a first episode of dislocation after primary total hip replacement (THR) to clarify the incidence of recurrent dislocation, the need for subsequent revision and the quality of life of these patients.

Over a six-year period, 99 patients (101 hips) presented with a first dislocation of a primary THR. A total of 61 hips (60.4%) had dislocated more than once. After a minimum follow-up of one year, seven patients had died. Of the remaining 94 hips (92 patients), 47 underwent a revision for instability and one awaits operation (51% in total). Of these, seven re-dislocated and four needed further surgery. The quality of life of the patients was studied using the Oxford Hip Score and the EuroQol-5 Dimension (EQ-5D) questionnaire. A control group of patients who had not dislocated was also studied. At a mean follow-up of 4.5 years (1 to 20), the mean Oxford Hip Score was 26.7 (15 to 47) after one episode of dislocation, 27.2 (12 to 45) after recurrent dislocation, 34.5 (12 to 54) after successful revision surgery, 42 (29 to 55) after failed revision surgery and 17.4 (12 to 32) in the control group. The EuroQol-5 dimension questionnaire revealed more health problems in patients undergoing revision surgery.

Aims

There are many guidelines that help direct the management of patients with metal-on-metal (MOM) hip arthroplasties. We have undertaken a study to compare the management of patients with MOM hip arthroplasties in different countries.