Aims

Loss or absence of proximal femoral bone in revision total hip arthroplasty (THA) remains a significant challenge. While the main indication for the use of proximal femoral replacements (PFRs) is in the treatment of malignant disease, they have a valuable role in revision THA for loosening, fracture and infection in patients with bone loss. Our aim was to determine the clinical outcomes, implant survivorship, and complications of PFRs used in revision THA for indications other than malignancy.

There is increasing global awareness of adverse reactions to metal debris and elevated serum metal ion concentrations following the use of second generation metal-on-metal total hip arthroplasties. The high incidence of these complications can be largely attributed to corrosion at the head-neck interface. Severe corrosion of the taper is identified most commonly in association with larger diameter femoral heads. However, there is emerging evidence of varying levels of corrosion observed in retrieved components with smaller diameter femoral heads. This same mechanism of galvanic and mechanically-assisted crevice corrosion has been observed in metal-on-polyethylene and ceramic components, suggesting an inherent biomechanical problem with current designs of the head-neck interface.

We provide a review of the fundamental questions and answers clinicians and researchers must understand regarding corrosion of the taper, and its relevance to current orthopaedic practice.

Cite this article: Bone Joint J 2016;98-B:579–84.

Oxidised zirconium (OxZi) has been developed as an alternative bearing surface for femoral heads in total hip arthroplasty (THA). This study has investigated polyethylene wear, functional outcomes and complications, comparing OxZi and cobalt–chrome (CoCr) as part of a three-arm, multicentre randomised controlled trial. Patients undergoing THA from four institutions were prospectively randomised into three groups. Group A received a CoCr femoral head and highly cross-linked polyethylene (XLPE) liner; Group B received an OxZi femoral head and XLPE liner; Group C received an OxZi femoral head and ultra-high molecular weight polyethylene (UHMWPE) liner. At five years, 368 patients had no statistically significant differences in short-form-36 (p = 0.176 mental, p = 0.756 physical), Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.847), pain scores (p = 0.458) or complications. The mean rate of linear wear was 0.028 mm/year (standard deviation (sd) 0.010) for Group A, 0.023 mm/year (sd 0.010) for Group B, and 0.09 mm/year (sd 0.045) for Group C. Penetration was significantly higher in the UHMWPE liner group compared with both XLPE liner groups (p < 0.001) but no significant difference was noted between CoCr and OxZi when articulating with XLPE (p = 0.153). In this, the largest randomised study of this bearing surface, it appears that using a XLPE acetabular liner is more important in reducing THA component wear than the choice of femoral head bearing, at mid-term follow-up. There is a non-significant trend towards lower wear, coupling OxZi rather than CoCr with XLPE but long-term analysis is required to see if this observation changes with time and becomes significant.

Cite this article: Bone Joint J 2015;97-B:883–9.

Aims

Advocates of debridement, antibiotics and implant retention (DAIR) in hip periprosthetic joint infection (PJI) argue that a procedure not disturbing a sound prosthesis-bone interface is likely to lead to better survival and functional outcome compared with revision. This case-control study aims were to compare outcome of DAIRs for infected primary total hip arthroplasty (THA) with outcomes following primary THA and two-stage revision of infected primary THAs.

Data on early morbidity and complications after revision total hip replacement (THR) are limited. The aim of this nationwide study was to describe and quantify early morbidity after aseptic revision THR and relate the morbidity to the extent of the revision surgical procedure. We analysed all aseptic revision THRs from 1st October 2009 to 30th September 2011 using the Danish National Patient Registry, with additional information from the Danish Hip Arthroplasty Registry. There were 1553 procedures (1490 patients) performed in 40 centres and we divided them into total revisions, acetabular component revisions, femoral stem revisions and partial revisions. The mean age of the patients was 70.4 years (25 to 98) and the median hospital stay was five days (interquartile range 3 to 7). Within 90 days of surgery, the readmission rate was 18.3%, mortality rate 1.4%, re-operation rate 6.1%, dislocation rate 7.0% and infection rate 3.0%. There were no differences in these outcomes between high- and low-volume centres. Of all readmissions, 255 (63.9%) were due to ‘surgical’ complications versus 144 (36.1%) ‘medical’ complications. Importantly, we found no differences in early morbidity across the surgical subgroups, despite major differences in the extent and complexity of operations. However, dislocations and the resulting morbidity represent the major challenge for improvement in aseptic revision THR.

Cite this article: Bone Joint J 2014; 96-B:1464–71.

Aims

To investigate the longevity of uncemented fixation of a femoral component in total hip arthroplasty (THA) in patients with Dorr type C proximal femoral morphology.

Aims

Our first aim was to determine whether there are significant changes in the level of metal ions in the blood at mid-term follow-up, in patients with an Articular Surface Replacement (ASR) arthroplasty. Secondly, we sought to identify risk factors for any increases.

Aims

The aim of this study was to identify patient- and surgery-related risk factors for sustaining an early periprosthetic fracture following primary total hip arthroplasty (THA) performed using a double-tapered cementless femoral component (Bi-Metric femoral stem; Biomet Inc., Warsaw, Indiana).

This study reports the results of 38 total hip arthroplasties (THAs) in 33 patients aged <  50 years, using the JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component. This represents an update of previous reports of the same cohort at ten and 16 years, which were reported in 2004 and 2009, respectively. We describe the survival, radiological and functional outcomes at a mean follow-up of 21 years (17 to 25). Of the surviving 34 THAs, one underwent femoral revision for peri-prosthetic fracture after 21 years, and one patient (one hip) was lost to follow-up. Using aseptic loosening as the end-point, 12 hips (31.5%) needed acetabular revision but none needed femoral revision, demonstrating 100% survival (95% confidence interval 89 to 100).

In young patients with high demands, the Furlong HAC–coated femoral component gives excellent long-term results.

Cite this article: Bone Joint J 2015;97-B:749–54.

Cemented femoral stems with force closed fixation designs have shown good clinical results despite high early subsidence. A new triple-tapered stem in this category (C-stem AMT) was introduced in 2005. This study compares this new stem with an established stem of similar design (Exeter) in terms of migration (as measured using radiostereometric analysis), peri-prosthetic bone remodelling (measured using dual energy x-ray densitometry, DXA), Oxford Hip Score, and plain radiographs.

A total of 70 patients (70 hips) with a mean age of 66 years (53 to 78) were followed for two years. Owing to missing data of miscellaneous reasons, the final analysis represents data from 51 (RSA) and 65 (DXA) patients. Both stems showed a typical pattern of migration: Subsidence and retroversion that primarily occurred during the first three months. C-stem AMT subsided less during the first three months (p = 0.01), before stabilising at a subsidence rate similar to the Exeter stem from years one to two. The rate of migration into retroversion was slightly higher for C-stem AMT during the second year (p = 0.03). Whilst there were slight differences in movement patterns between the stems, the C-stem AMT exhibits good early clinical outcomes and displays a pattern of migration and bone remodelling that predicts good clinical performance.

Cite this article: Bone Joint J 2015;97-B:755–61.

The accurate reconstruction of hip anatomy and biomechanics is thought to be important in achieveing good clinical outcomes following total hip arthroplasty (THA). To this end some newer hip designs have introduced further modularity into the design of the femoral component such that neck­shaft angle and anteversion, which can be adjusted intra-operatively. The clinical effect of this increased modularity is unknown. We have investigated the changes in these anatomical parameters following conventional THA with a prosthesis of predetermined neck–shaft angle and assessed the effect of changes in the hip anatomy on clinical outcomes.

In total, 44 patients (mean age 65.3 years (standard deviation (sd) 7); 17 male/27 female; mean body mass index 26.9 (kg/m²) (sd 3.1)) underwent a pre- and post-operative three-dimensional CT scanning of the hip. The pre- and post-operative neck–shaft angle, offset, hip centre of rotation, femoral anteversion, and stem alignment were measured. Additionally, a functional assessment and pain score were evaluated before surgery and at one year post-operatively and related to the post-operative anatomical changes.

The mean pre-operative neck–shaft angle was significantly increased by 2.8° from 128° (sd 6.2; 119° to 147°) to 131° (sd 2.1; 127° to 136°) (p = 0.009). The mean pre-operative anteversion was 24.9° (sd 8; 7.9 to 39.1) and reduced to 7.4° (sd 7.3; -11.6° to 25.9°) post-operatively (p < 0.001). The post-operative changes had no influence on function and pain. Using a standard uncemented femoral component, high pre- and post-operative variability of femoral anteversion and neck–shaft angles was found with a significant decrease of the post-operative anteversion and slight increase of the neck–shaft angles, but without any impact on clinical outcome.

Cite this article: Bone Joint J 2015;97-B:1615–22.

We investigated the incidence of soft-tissue lesions after small head metal-on-metal total hip replacement (MoM THR). Between December 1993 and May 1999, 149 patients (195 hips) underwent primary cementless MoM THR.

During the follow-up period, three patients (five THRs) died and eight patients (14 THRs) were lost to follow-up. We requested that all patients undergo CT evaluation. After exclusion of five patients (six THRs) who had undergone a revision procedure, and 22 (28 THRs) who were unwilling to take part in this study, 111 patients (142 THRs) were evaluated. There were 63 men (88 THRs) and 48 women (54 THRs) with a mean age of 45.7 years (37 to 56) at the time of surgery. The mean follow-up was 15.4 years (13 to 19). A soft-tissue lesion was defined as an abnormal peri-prosthetic collection of fluid, solid lesion or asymmetrical soft-tissue mass.

At final follow-up, soft-tissue lesions were found in relation to 28 THRs (19.7%), including 25 solid and three cystic lesions. They were found in 20 men and eight women; 26 lesions were asymptomatic and two were symptomatic. The mean maximal diameter of the soft-tissue lesion was 42.3 mm (17 to 135). The relatively high rate of soft-tissue lesions observed with small head MoM THR remains a concern.

Cite this article: Bone Joint J 2014;96-B:1594–9.

Aims

We wished to investigate the influence of metal debris exposure on the subsequent immune response and resulting soft-tissue injury following metal-on-metal (MoM) hip arthroplasty. Some reports have suggested that debris generated from the head-neck taper junction is more destructive than equivalent doses from metal bearing surfaces.

Aims

We investigated changes in the axial alignment of the ipsilateral hip and knee after total hip arthroplasty (THA).

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.

Concerns have been raised that deformation of acetabular shells may disrupt the assembly process of modular prostheses. In this study we aimed to examine the effect that the strength of bone has on the amount of deformation of the acetabular shell. The hypothesis was that stronger bone would result in greater deformation. A total of 17 acetabular shells were inserted into the acetabula of eight cadavers, and deformation was measured using an optical measuring system. Cores of bone from the femoral head were taken from each cadaver and compressed using a materials testing machine. The highest peak modulus and yield stress for each cadaver were used to represent the strength of the bone and compared with the values for the deformation and the surgeon’s subjective assessment of the hardness of the bone. The mean deformation of the shell was 129 µm (3 to 340). No correlation was found between deformation and either the maximum peak modulus (r² = 0.011, t = 0.426, p = 0.676) or the yield stress (r² = 0.024, t = 0.614, p = 0.549) of the bone. Although no correlation was found between the strength of the bone and deformation, the values for the deformation observed could be sufficient to disrupt the assembly process of modular acetabular components.

Cite this article: Bone Joint J 2015; 97-B:473–7.

Objectives

High failure rates of metal-on-metal hip arthroplasty implants have highlighted the need for more careful introduction and monitoring of new implants and for the evaluation of the safety of medical devices. The National Joint Registry and other regulatory services are unable to detect failing implants at an early enough stage. We aimed to identify validated surrogate markers of long-term outcome in patients undergoing primary total hip arthroplasty (THA).

Nerve palsy is a well-described complication following total hip arthroplasty, but is highly distressing and disabling. A nerve palsy may cause difficulty with the post-operative rehabilitation, and overall mobility of the patient. Nerve palsy may result from compression and tension to the affected nerve(s) during the course of the operation via surgical manipulation and retractor placement, tension from limb lengthening or compression from post-operative hematoma. In the literature, hip dysplasia, lengthening of the leg, the use of an uncemented femoral component, and female gender are associated with a greater risk of nerve palsy. We examined our experience at a high-volume, tertiary care referral centre, and found an overall incidence of 0.3% out of 39 056 primary hip arthroplasties. Risk factors found to be associated with the incidence of nerve palsy at our institution included the presence of spinal stenosis or lumbar disc disease, age younger than 50, and smoking. If a nerve palsy is diagnosed, imaging is mandatory and surgical evacuation or compressive haematomas may be beneficial. As palsies are slow to recover, supportive care such as bracing, therapy, and reassurance are the mainstays of treatment.

Cite this article: Bone Joint J 2017;99-B(1 Supple A):46–9.

Aims

To analyse the effectiveness of debridement and implant retention (DAIR) in patients with hip periprosthetic joint infection (PJI) and the relationship to patient characteristics. The outcome was evaluated in hips with confirmed PJI and a follow-up of not less than two years.