Aims

The aim of this study was to evaluate the suitability of the tapered cone stem in total hip arthroplasty (THA) in patients with excessive femoral anteversion and after femoral osteotomy.

Aims

This study reports the results of 38 total hip arthroplasties (THAs) in 33 patients aged less than 50 years, using the JRI Furlong hydroxyapatite ceramic (HAC)-coated femoral component.

Aims

There are concerns regarding complications and longevity of total elbow arthroplasty (TEA) in young patients, and the few previous publications are mainly limited to reports on linked elbow devices. We investigated the clinical outcome of unlinked TEA for patients aged less than 50 years with rheumatoid arthritis (RA).

Aims

The Exeter V40 cemented femoral stem was first introduced in 2000. The largest single-centre analysis of this implant to date was published in 2018 by Westerman et al. Excellent results were reported at a minimum of ten years for the first 540 cases performed at the designer centre in the Exeter NHS Trust, with stem survivorship of 96.8%. The aim of this current study is to report long-term outcomes and survivorship for the Exeter V40 stem in a non-designer centre.

Aims

To compare long-term survival of all-cemented and hybrid total hip arthroplasty (THA) using the Exeter Universal stem.

Ceramic bearings have several desirable properties, such as resistance to wear, hardness, and biocompatibility, that favour it as an articulating surface in hip arthroplasty. However, ceramic fracture remains a concern. We have reviewed the contemporary literature, addressing the factors that can influence the incidence of ceramic bearing surface fracture.

Cite this article: Bone Joint J 2019;101-B:897–901.

Aims. Total ankle arthroplasty (TAA) has become the most reliable surgical solution for patients with end-stage arthritis of the ankle. Aseptic loosening of the talar component is the most common complication. A custom-made artificial talus can be used as the talar component in a combined TAA for patients with poor bone stock of the talus. The purpose of this study was to investigate the functional and clinical outcomes of combined TAA. Patients and Methods. Ten patients (two men, eight women; ten ankles) treated using a combined TAA between 2009 and 2013 were matched for age, gender, and length of follow-up with 12 patients (one man, 11 women; 12 ankles) who underwent a standard TAA. All had end-stage arthritis of the ankle. The combined TAA features a tibial component of the TNK ankle (Kyocera, Kyoto, Japan) and an alumina ceramic artificial talus (Kyocera), designed using individualized CT data. The mean age at the time of surgery in the combined TAA and standard TAA groups was 71 years (. 61. to 82) and 75 years (62 to 82), respectively. The mean follow-up was 58 months (43 to 81) and 64 months (48 to 88), respectively. The outcome was assessed using the Japanese Society for Surgery of the Foot (JSSF) ankle-hindfoot scale, the Ankle Osteoarthritis Scale (AOS), and the Self-Administered Foot Evaluation Questionnaire (SAFE-Q). Results. The mean preoperative JSSF score of the combined TAA and standard TAA groups was 44 (. sd. 11) and 49 (. sd. 10), respectively. The mean postoperative JSSF scores were 89 (. sd. 6.1) and 72 (. sd. 15), respectively. The mean postoperative JSSF score of the combined TAA group was significantly higher (p = 0.0034). The mean preoperative AOS scores for pain and function in the combined TAA and standard TAA groups were 5.8 (. sd. 3.3) and 5.5 (. sd. 3.1), and 8.6 (. sd. 1.3), and 7.1 (. sd. 2.9), respectively. The mean postoperative AOS scores of pain and function were 2.5 (. sd. 2.5) and 2.2 (. sd. 1.9), and 2.5 (. sd. 3.3) and 3.4 (. sd. 2.9), respectively. There were no significant differences between the two groups in terms of postoperative AOS scores. The mean postoperative SAFE-Q scores were: for pain, 76 (. sd. 23) and 70 (. sd. 23); for physical function, 66 (. sd. 25) and 55 (. sd. 27); for social function, 73 (. sd. 35) and 62 (. sd. 34); for shoe-related, 73 (. sd. 19) and 65 (. sd. 26); and for general health, 78 (. sd. 28) and 67 (. sd. 29), respectively. There were no significant differences between the two groups in terms of postoperative SAFE-Q scores. Conclusion. Combined TAA resulted in better clinical results than standard TAA. Cite this article: Bone Joint J 2019;101-B:443–446

Aims

The aim of this study was to report the mid-term clinical outcome of cemented unlinked J-alumina ceramic elbow (JACE) arthroplasties when used in patients with rheumatoid arthritis (RA).

Despite its intrinsic ability to regenerate form and function after injury, bone tissue can be challenged by a multitude of pathological conditions. While innovative approaches have helped to unravel the cascades of bone healing, this knowledge has so far not improved the clinical outcomes of bone defect treatment. Recent findings have allowed us to gain in-depth knowledge about the physiological conditions and biological principles of bone regeneration. Now it is time to transfer the lessons learned from bone healing to the challenging scenarios in defects and employ innovative technologies to enable biomaterial-based strategies for bone defect healing. This review aims to provide an overview on endogenous cascades of bone material formation and how these are transferred to new perspectives in biomaterial-driven approaches in bone regeneration.

Cite this article: T. Winkler, F. A. Sass, G. N. Duda, K. Schmidt-Bleek. A review of biomaterials in bone defect healing, remaining shortcomings and future opportunities for bone tissue engineering: The unsolved challenge. Bone Joint Res 2018;7:232–243. DOI: 10.1302/2046-3758.73.BJR-2017-0270.R1.

Aims. Our aim in this study was to describe a continuing review of 11 total hip arthroplasties using 22.225 mm Alumina ceramic femoral heads on a Charnley flanged femoral component, articulating against a silane crosslinked polyethylene. Patients and Methods. Nine patients (11 THAs) were reviewed at a mean of 27.5 years (26 to 28) post-operatively. Outcome was assessed using the d’Aubigne and Postel, and Charnley scores and penetration was recorded on radiographs. In addition, the oxidation of a 29-year-old shelf-aged acetabular component was analysed. Results. The mean clinical outcome scores remained excellent at final follow-up. The mean total penetration remained 0.41 mm (0.40 to 0.41). There was no radiographic evidence of acetabular or femoral loosening or osteolysis. There was negligible oxidation in the shelf-aged sample despite gamma irradiation and storage in air. Conclusion. These results highlight the long-term stability and durability of this type of crosslinked, antioxidant containing polyethylene when used in combination with a small diameter alumina ceramic femoral head. Cite this article: Bone Joint J 2017;99-B:1286–9

Aims

Ceramic-on-ceramic (CoC) bearings in total hip arthroplasty (THA) are commonly used, but concerns exist regarding ceramic fracture. This study aims to report the risk of revision for fracture of modern CoC bearings and identify factors that might influence this risk, using data from the National Joint Registry (NJR) for England, Wales, Northern Ireland and the Isle of Man.

Aims

To determine the effect of a change in design of a cementless ceramic acetabular component in fixation and clinical outcome after total hip arthroplasty

Aims

We conducted a prospective study of a delta ceramic total hip arthroplasty (THA) to determine the rate of ceramic fracture, to characterise post-operative noise, and to evaluate the mid-term results and survivorship.

Objectives

Studies reporting specifically on squeaking in total hip arthroplasty have focused on cementless, and not on hybrid, fixation. We hypothesised that the cement mantle of the femur might have a damping effect on the sound transmitted through the metal stem. The objective of this study was to test the effect of cement on sound propagation along different stem designs and under different fixation conditions.

Most published randomised controlled trials which compare the rates of wear of conventional and cross-linked (XL) polyethylene (PE) in total hip arthroplasty (THA) have described their use with a cementless acetabular component.

We conducted a prospective randomised study to assess the rates of penetration of two distinct types of PE in otherwise identical cemented all-PE acetabular components.

A total of 100 consecutive patients for THA were randomised to receive an acetabular component which had been either highly XL then remelted or moderately XL then annealed.

After a minimum of eight years follow-up, 38 hips in the XL group and 30 hips in the annealed group had complete data (mean follow-up of 9.1 years (7.6 to 10.7) and 8.7 years (7.2 to 10.2), respectively). In the XL group, the steady state rate of penetration from one year onwards was -0.0002 mm/year (sd 0.108): in the annealed group it was 0.1382 mm/year (sd 0.129) (Mann–Whitney U test, p < 0.001). No complication specific to either material was recorded.

These results show that the yearly linear rate of femoral head penetration can be significantly reduced by using a highly XLPE cemented acetabular component.

Cite this article: Bone Joint J 2015;97-B:1458–62.

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.

Large femoral heads have become popular in total hip replacement (THR) as a method of reducing the risk of dislocation. However, if large heads are used in ceramic-on-ceramic THR, the liner must be thinner, which may increase the risk of fracture. To compare the rates of ceramic fracture and dislocation between 28 mm and 32 mm ceramic heads, 120 hips in 109 patients (51 men and 58 women, mean age 49.2 years) were randomised to THR with either a 28 mm or a 32 mm ceramic articulation. A total of 57/60 hips assigned to the 28 mm group and 55/60 hips assigned to the 32 mm group were followed for at least five years. No ceramic component fractures occured in any patient in either group. There was one dislocation in the 32 mm group and none in the 28 mm group (p = 0.464). No hip had detectable wear, focal osteolysis or prosthetic loosening. In our small study the 32 mm ceramic articulation appeared to be safe in terms of ceramic liner fracture.

Cite this article: Bone Joint J 2014;96-B:1459–63.

Large-head metal-on-metal (MoM) total hip replacements (THR) have given rise to concern. Comparative studies of small-head MoM THRs over a longer follow-up period are lacking. Our objective was to compare the incidence of complications such as infection, dislocation, revision, adverse local tissue reactions, mortality and radiological and clinical outcomes in small-head (28 mm) MoM and ceramic-on-polyethylene (CoP) THRs up to 12 years post-operatively.

A prospective cohort study included 3341 THRs in 2714 patients. The mean age was 69.1 years (range 24 to 98) and 1848 (55.3%) were performed in women, with a mean follow-up of 115 months (18 to 201). There were 883 MoM and 2458 CoP bearings. Crude incidence rates (cases/1000 person-years) were: infection 1.3 vs 0.8; dislocation 3.3 vs 3.1 and all-cause revision 4.3 vs 2.2, respectively. There was a significantly higher revision rate after ten years (adjusted hazard ratio 9.4; 95% CI 2.6 to 33.6) in the MoM group, and ten of 26 patients presented with an adverse local tissue reaction at revision. No differences in mortality, osteolysis or clinical outcome were seen.

In conclusion, we found similar results for small-head MoM and CoP bearings up to ten years post-operatively, but after ten years MoM THRs had a higher risk of all-cause revision. Furthermore, the presence of an adverse response to metal debris seen in the small-head MOM group at revision is a cause for concern.

Cite this article: Bone Joint J 2014; 96-B:868–75.

We report on 397 consecutive revision total hip replacements in 371 patients with a mean clinical and radiological follow-up of 12.9 years (10 to 17.7). The mean age at surgery was 69 years (37 to 93). A total of 28 patients (8%) underwent further revision, including 16 (4%) femoral components. In all 223 patients (56%, 233 hips) died without further revision and 20 patients (5%, 20 hips) were lost to follow-up. Of the remaining patients, 209 (221 hips) were available for clinical assessment and 194 (205 hips) for radiological review at mean follow-up of 12.9 years (10 to 17.7).

The mean Harris Hip Score improved from 58.7 (11 to 92) points to 80.7 (21 to 100) (p <  0.001) and the mean Merle d’Aubigné and Postel hip scores at final follow-up were 4.9 (2 to 6), 4.5 (2 to 6) and 4.3 (2 to 6), respectively for pain, mobility and function. Radiographs showed no lucencies around 186 (90.7%) femoral stems with stable bony ingrowth seen in 199 stems (97%). The survival of the S-ROM femoral stem at 15 years with revision for any reason as the endpoint was 90.5% (95% confidence interval (CI) 85.7 to 93.8) and with revision for aseptic loosening as the endpoint 99.3% (95% CI 97.2 to 99.8).

We have shown excellent long-term survivorship and good clinical outcome of a cementless hydroxyapatite proximally-coated modular femoral stem in revision hip surgery.

Cite this article: Bone Joint J 2014;96-B:730–6.

We report the clinical and radiological outcomes of a series of contemporary cementless ceramic-on-ceramic total hip replacements (THRs) at ten years in patients aged ≤ 55 years of age. Pre- and post-operative activity levels are described. A total of 120 consecutive ceramic cementless THRs were performed at a single centre in 110 patients from 1997 to 1999. The mean age of the patients at operation was 45 years (20 to 55). At ten years, four patients had died and six were lost to follow-up, comprising ten hips. The mean post-operative Harris hip score was 94.7 (55 to 100). Radiological analysis was undertaken in 90 available THRs of the surviving 106 hips at final review: all had evidence of stable bony ingrowth, with no cases of osteolysis. Wear was undetectable. There were four revisions. The survival for both components with revision for any cause as an endpoint was 96.5% (95% confidence interval 94.5 to 98.7). The mean modified University of California, Los Angeles activity level rose from a mean of 6.4 (4 to 10) pre-operatively to 9.0 (6 to 10) at the ten-year post-operative period.

Alumina ceramic-on-ceramic bearings in cementless primary THR in this series have resulted in good clinical and radiological outcomes with undetectable rates of wear and excellent function in the demanding younger patient group at ten years.

Cite this article: Bone Joint J 2013;95-B:1603–9.

Symptomatic hip osteonecrosis is a disabling condition with a poorly understood aetiology and pathogenesis. Numerous treatment options for hip osteonecrosis are described, which include non-operative management and joint preserving procedures, as well as total hip replacement (THR). Non-operative or joint preserving treatment may improve outcomes when an early diagnosis is made before the lesion has become too large or there is radiographic evidence of femoral head collapse. The presence of a crescent sign, femoral head flattening, and acetabular involvement indicate a more advanced-stage disease in which joint preserving options are less effective than THR. Since many patients present after disease progression, primary THR is often the only reliable treatment option available. Prior to the 1990s, outcomes of THR for osteonecrosis were poor. However, according to recent reports and systemic reviews, it is encouraging that with the introduction of newer ceramic and/or highly cross-linked polyethylene bearings as well as highly-porous fixation interfaces, THR appears to be a reliable option in the management of end-stage arthritis following hip osteonecrosis in this historically difficult to treat patient population.

Cite this article: Bone Joint J 2013;95-B, Supple A:46–50.

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

We prospectively assessed the efficacy of a ceramic-on-metal (CoM) hip bearing with uncemented acetabular and femoral components in which cobalt­–chrome acetabular liners and alumina ceramic heads were used. The cohort comprised 94 total hip replacements (THRs) in 83 patients (38 women and 45 men) with a mean age of 58 years (42 to 70). Minimum follow-up was two years. All patients had pre- and post-operative assessment using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC), Oxford hip score and Short-Form 12 scores. All showed a statistically significant improvement from three months post-operatively onwards (all p < 0.001). After two years whole blood metal ion levels were measured and chromosomal analysis was performed. The levels of all metal ions were elevated except vanadium. Levels of chromium, cobalt, molybdenum and titanium were significantly higher in patients who underwent bilateral THR compared with those undergoing unilateral THR (p < 0.001). Chromosomal analysis demonstrated both structural and aneuploidy mutations. There were significantly more breaks and losses than in the normal population (p < 0.001). There was no significant difference in chromosomal aberration between those undergoing unilateral and bilateral procedures (all analyses p ≥ 0.62). The use of a CoM THR is effective clinically in the short-term, with no concerns, but the significance of high metal ion levels and chromosomal aberrations in the long-term remains unclear. Cite this article: Bone Joint J 2013;95-B:1040–44

The practice of removing a well-fixed cementless femoral component is associated with high morbidity. Ceramic bearing couples are low wearing and their use minimises the risk of subsequent further revision due to the production of wear debris. A total of 165 revision hip replacements were performed, in which a polyethylene-lined acetabular component was revised to a new acetabular component with a ceramic liner, while retaining the well-fixed femoral component. A titanium sleeve was placed over the used femoral trunnion, to which a ceramic head was added. There were 100 alumina and 65 Delta bearing couples inserted.

The mean Harris hip score improved significantly from 71.3 (9.0 to 100.0) pre-operatively to 91.0 (41.0 to 100.0) at a mean follow up of 4.8 years (2.1 to 12.5) (p < 0.001). No patients reported squeaking of the hip.

There were two fractures of the ceramic head, both in alumina bearings. No liners were seen to fracture. No fractures were observed in components made of Delta ceramic. At 8.3 years post-operatively the survival with any cause of failure as the endpoint was 96.6% (95% confidence interval (CI) 85.7 to 99.3) for the acetabular component and 94.0% (95% CI 82.1 to 98.4) for the femoral component.

The technique of revising the acetabular component in the presence of a well-fixed femoral component with a ceramic head placed on a titanium sleeve over the used trunnion is a useful adjunct in revision hip practice. The use of Delta ceramic is recommended.

Cite this article: Bone Joint J 2013;95-B:333–8.

In this paper, we will consider the current role of metal-on-metal bearings by looking at three subtypes of MoM hip arthroplasty separately: Hip resurfacing, large head (> 36 mm) MoM THA and MoM THA with traditional femoral head sizes.

A moderator and panel of five experts led an interactive session in discussing five challenging and interesting patient case presentations involving surgery of the hip. The hip pathologies reviewed included failed open reduction internal fixation of subcapital femoral neck fracture, bilateral hip disease, evaluation of pain after metal-on-metal hip arthroplasty, avascular necrosis, aseptic loosening secondary to osteolysis and polyethylene wear, and management of ceramic femoral head fracture.

The purpose of this study was to evaluate the clinical results of a newly designed prosthesis to replace the body of the talus in patients with aseptic necrosis. Between 1999 and 2006, 22 tali in 22 patients were replaced with a ceramic prosthesis. A total of eight patients were treated with the first-generation prosthesis, incorporating a peg to fix into the retained neck and head of the talus, and the remaining 14 were treated with the second-generation prosthesis, which does not have the peg. The clinical results were assessed by the American Orthopaedic Foot and Ankle Society ankle/hindfoot scale.

The mean follow-up was 98 months (18 to 174). The clinical results of the first-generation prostheses were excellent in three patients, good in one, fair in three and poor in one. There were, however, radiological signs of loosening, prompting a change in design. The clinical results of the second-generation prostheses were excellent in three patients, good in five, fair in four and poor in two, with more favourable radiological appearances. Revision was required using a total talar implant in four patients, two in each group.

Although the second-generation prosthesis produced better results, we cannot recommend the use of a talar body prosthesis. We now recommend the use of a total talar implant in these patients.

Hip implant retrieval analysis is the most important source of insight into the performance of new materials and designs of hip arthroplasties. Even the most rigorous in vitro testing will not accurately simulate the behavior of implant materials and new designs of prosthetic arthroplasties. Retrieval analysis has revealed such factors as the effects of gamma-in-air sterilisation of polyethylene, fatigue failure mechanisms of polymethylmethacrylate bone cement, fretting corrosion of Morse taper junctions, third body wear effects of both hard-on-hard and hard-on-soft bearing couples, and the effects of impingement of components on the full spectrum of bearing surfaces, none of which was predicted by pre-implantation in vitro testing of these materials and combinations. The temporal sequence of the retrieval process is approximately six years from first implantation through retrieval analysis, laboratory investigation, and publication of results, and thus, in addition to rigorous clinical evaluation, represents the true development and insight cycle for new designs and materials.

We analysed 54 alumina ceramic-on-ceramic bearings from total hip replacements retrieved at one centre after a mean duration of 3.5 years (0.2 to 10.6) in situ. These implants were obtained from 54 patients (16 men and 38 women) with a mean age of 67 years (33 to 88) who underwent revision for a variety of reasons. Posterior edge loading was found in the majority of these retrievals (32 out of 54). Anterosuperior edge loading occurred less often but produced a higher rate of wear. Stripe wear on the femoral heads had a median volumetric wear rate of 0.2 mm³/year (0 to 7.2). The wear volume on the femoral heads corresponded to the width of edge wear on the matching liner. Anteversion of the acetabular component was found to be a more important determinant than inclination for wear in ceramic bearings. Posterior edge loading may be considered to be a normal occurrence in ceramic-on-ceramic bearings, with minimal clinical consequences. Edge loading should be defined as either anterosuperior or posterior, as each edge loading mechanism may result in different clinical implications.

Fracture of a ceramic component in total hip replacement is a rare but potentially catastrophic complication. The incidence is likely to increase as the use of ceramics becomes more widespread. We describe such a case, which illustrates how inadequate initial management will lead to further morbidity and require additional surgery. We present the case as a warning that fracture of a ceramic component should be revised to another ceramic-on-ceramic articulation in order to minimise the risk of further catastrophic wear.

This multicentre study analysed 12 alumina ceramic-on-ceramic components retrieved from squeaking total hip replacements after a mean of 23 months in situ (11 to 61). The rates and patterns of wear seen in these squeaking hips were compared with those seen in matched controls using retrieval data from 33 ‘silent’ hip replacements with similar ceramic bearings. All 12 bearings showed evidence characteristic of edge-loading wear. The median rate of volumetric wear was 3.4 mm³/year for the acetabular component, 2.9 mm³/year on the femoral heads and 6.3 mm³/year for head and insert combined. This was up to 45 times greater than that of previously reported silent ceramic-on-ceramic retrievals. The rate of wear seen in ceramic components revised for squeaking hips appears to be much greater than in that seen in retrievals from ‘silent’ hips.

Bioengineering reasons for increased wear and failure of metal-on-metal (MoM) bearings in hip prostheses have been described. Low wear occurs in MoM hips when the centre of the femoral head is concentric with the centre of the acetabular component and the implants are correctly positioned. Translational or rotational malpositioning of the components can lead to the contact-patch of the femoral component being displaced to the rim of the acetabular component, resulting in a ten- to 100-fold increase in wear and metal ion levels. This may cause adverse tissue reactions, loosening of components and failure of the prosthesis.

We investigated factors that were thought to be associated with an increased incidence of squeaking of ceramic-on-ceramic total hip replacements. Between June 1997 and December 2008 the three senior authors implanted 2406 primary total hip replacements with a ceramic-on-ceramic bearing surface. The mean follow-up was 10.6 years. The diagnosis was primary osteoarthritis in each case, and no patient had undergone previous surgery to the hip. We identified 74 squeaking hips (73 patients) giving an incidence of 3.1% at a mean follow-up of 9.5 years (4.1 to 13.3).

Taller, heavier and younger patients were significantly more likely to have hips that squeaked. Squeaking hips had a significantly higher range of post-operative internal (p = 0.001) and external rotation (p = 0.003) compared with silent hips. Patients with squeaking hips had significantly higher activity levels (p = 0.009). A squeaking hip was not associated with a significant difference in patient satisfaction (p = 0.24) or Harris hip score (p = 0.34). Four implant position factors enabled good prediction of squeaking. These were high acetabular component inclination, high femoral offset, lateralisation of the hip centre and either high or low acetabular component anteversion.

This is the largest study to date to examine patient factors and implant position factors that predispose to squeaking of a ceramic-on-ceramic hip. The results suggest that factors which increase the mechanical forces across the hip joint and factors which increase the risk of neck-to-rim impingement, and therefore edge-loading, are those that predispose to squeaking.

We conducted a longitudinal study including patients with the same type of primary hybrid total hip replacement and evaluated patient activity and femoral osteolysis at either five or ten years post-operatively. Activity was measured using the University of California, Los Angeles scale. The primary outcome was the radiological assessment of femoral osteolysis. Secondary outcomes were revision of the femoral component for aseptic loosening and the patients’ quality of life. Of 503 hip replacements in 433 patients with a mean age of 67.7 years (30 to 91), 241 (48%) were seen at five and 262 (52%) at ten years post-operatively. Osteolytic lesions were identified in nine of 166 total hip replacements (5.4%) in patients with low activity, 21 of 279 (7.5%) with moderate activity, and 14 of 58 (24.1%) patients with high activity. The risk of osteolysis increased with participation in a greater number of sporting activities. In multivariate logistic regression adjusting for age, gender, body mass index and the inclination angle of the acetabular component, the adjusted odds ratio for osteolysis comparing high vs moderate activity was 3.6 (95% confidence interval 1.6 to 8.3). Stratification for the cementing technique revealed that lower quality cementing increased the effect of high activity on osteolysis. Revision for aseptic loosening was most frequent with high activity. Patients with the highest activity had the best outcome and highest satisfaction.

In conclusion, of patients engaged in high activity, 24% had developed femoral osteolysis five to ten years post-operatively.

Metallosis is a rare cause of failure after total knee replacement and has only previously been reported when there has been abnormal metal-on-metal contact. We describe 14 patients (15 knees) whose total knee replacement required revision for a new type of early failure caused by extensive metallosis. A modification of a cementless rotating platform implant, which had previously had excellent long-term survival, had been used in each case. The change was in the form of a new porous-beaded surface on the femoral component to induce cementless fixation, which had been used successfully in the fixation of acetabular and tibial components. This modification appeared to have resulted in metallosis due to abrasive two-body wear. The component has subsequently been recalled and is no longer in use. The presentation, investigation, and findings at revision are described and a possible aetiology and its implications are discussed.

The long-term results of grafting with hydroxyapatite granules for acetabular deficiency in revision total hip replacement are not well known. We have evaluated the results of revision using a modular cup with hydroxyapatite grafting for Paprosky type 2 and 3 acetabular defects at a minimum of ten years’ follow-up. We retrospectively reviewed 49 acetabular revisions at a mean of 135 months (120 to 178). There was one type 2B, ten 2C, 28 3A and ten 3B hips. With loosening as the endpoint, the survival rate was 74.2% (95% confidence interval 58.3 to 90.1). Radiologically, four of the type 3A hips (14%) and six of the type 3B hips (60%) showed aseptic loosening with collapse of the hydroxyapatite layer, whereas no loosening occurred in type 2 hips. There was consolidation of the hydroxyapatite layer in 33 hips (66%). Loosening was detected in nine of 29 hips (31%) without cement and in one of 20 hips (5%) with cement (p = 0.03, Fisher’s exact probability test). The linear wear and annual wear rate did not correlate with loosening.

These results suggest that the long-term results of hydroxyapatite grafting with cement for type 2 and 3A hips are encouraging.

We compared a modular neck system with a non-modular system in a cementless anatomical total hip replacement (THR). Each group consisted of 74 hips with developmental hip dysplasia. Both groups had the same cementless acetabular component and the same articulation, which consisted of a conventional polyethylene liner and a 28 mm alumina head. The mean follow-up was 14.5 years (13 to 15), at which point there were significant differences in the mean total Harris hip score (modular/non-modular: 98.6 (64 to 100)/93.8 (68 to 100)), the mean range of abduction (32° (15° to 40°)/28 (0° to 40°)), use of a 10° elevated liner (31%/100%), the incidence of osteolysis (27%/79.7%) and the incidence of equal leg lengths (≥ 6 mm, 92%/61%). There was no disassociation or fracture of the modular neck.

The modular system reduces the need for an elevated liner, thereby reducing the incidence of osteolysis. It gives a better range of movement and allows the surgeon to make an accurate adjustment of leg length.

Increasing follow-up identifies the outcome in younger patients who have undergone total hip replacement (THR) and reveals the true potential for survival of the prosthesis. We identified 28 patients (39 THRs) who had undergone cemented Charnley low friction arthroplasty between 1969 and 2001. Their mean age at operation was 17.9 years (12 to 19) and the maximum follow-up was 34 years. Two patients (4 THRs) were lost to follow-up, 13 (16 THRs) were revised at a mean period of 19.1 years (8 to 34) and 13 (19 THRs) continue to attend regular follow-up at a mean of 12.6 years (2.3 to 29). In this surviving group one acetabular component was radiologically loose and all femoral components were secure. In all the patients the diameter of the femoral head was 22.225 mm with Charnley femoral components used in 29 hips and C-stem femoral components in ten. In young patients who require THR the acetabular bone stock is generally a limiting factor for the size of the component. Excellent long-term results can be obtained with a cemented polyethylene acetabular component and a femoral head of small diameter.

The Norwegian Arthroplasty Register has shown that several designs of uncemented femoral stems give good or excellent survivorship. The overall findings for uncemented total hip replacement however, have been disappointing because of poor results with the use of metal-backed acetabular components. In this study, we exclusively investigated the medium-to long-term performance of primary uncemented metal-backed acetabular components. A total of 9113 primary uncemented acetabular components were implanted in 7937 patients between 1987 and 2007. These were included in a prospective, population-based observational study. All the implants were modular and metal-backed with ultra-high-molecular-weight polyethylene liners. The femoral heads were made of stainless steel, cobalt-chrome (CoCr) alloy or alumina ceramic. In all, seven different designs of acetabular component were evaluated by the Kaplan-Meier survivorship method and Cox regression analysis. Most acetabular components performed well up to seven years. When the endpoint was revision of the acetabular component because of aseptic loosening, the survival ranged between 87% and 100% at ten years. However, when the endpoint was revision for any reason, the survival estimates were 81% to 92% for the same implants at ten years. Aseptic loosening, wear, osteolysis and dislocation were the main reasons for the relatively poor overall performance of the acetabular components. Prostheses with alumina heads performed slightly better than those with stainless steel or CoCr alloy in subgroups. Whereas most acetabular components performed well at seven years, the survivorship declined with longer follow-up. Fixation was generally good. None of the metal-backed uncemented acetabular components with ultra-high-molecular-weight polyethylene liners in our study had satisfactory long-term results because of high rates of wear, osteolysis, aseptic loosening and dislocation

Surgeons remain concerned that ceramic hip prostheses may fail catastrophically if either the head or the liner is fractured. We report two patients, each with a ceramic-on-ceramic total hip replacement who sustained high-energy trauma sufficient to cause a displaced periprosthetic acetabular fracture in whom the ceramic bearings survived intact. Simultaneous fixation of the acetabular fracture, revision of the cementless acetabular prosthesis and exchange of the ceramic bearings were performed successfully in both patients. Improved methods of manufacture of new types of alumina ceramic with a smaller grain size, and lower porosity, have produced much stronger bearings. Whether patients should be advised to restrict high-impact activities in order to protect these modern ceramic bearings from fracture remains controversial

Polyethylene wear of acetabular components is a key factor in the development of periprosthetic osteolysis and wear at the articular surface has been well documented and quantified, but fewer data are available about changes which occur at the backside of the liner.

At revision surgery for loosening of the femoral component we retrieved 35 conventional modular acetabular liners of the same design. Linear and volumetric articular wear, backside volumetric change and the volume of the screw-head indentations were quantified. These volumes, clinical data and the results from radiological Ein Bild Röntgen Analyse migration analysis were used to identify potential factors influencing the volumetric articular wear and backside volumetric change.

The rate of backside volumetric change was found to be 2.8% of the rate of volumetric articular wear and decreased with increasing liner size. Migrated acetabular components showed significantly higher rates of backside volumetric change plus screw-head indentations than those without migration.

The backside volumetric change was at least ten times larger than finite-element simulation had suggested. In a stable acetabular component with well-anchored screws, the amount of backside wear should not cause clinical problems. Impingement of the screw-heads could produce more wear particles than those generated at the liner-shell interface. Because the rate of backside volumetric change is only 2.8% of the rate of volumetric articular wear and since creep is likely to contribute a significant portion to this, the debris generated by wear at the backside of the liner may not be sufficient to create a strong osteolytic response.

In 2004 we described the ten-year prospective results of 38 total hip replacements using the Furlong hydroxyapatite-ceramic-coated femoral component in 35 patients < 50 years old. We have now reviewed the surviving 35 arthroplasties in 33 patients at a mean of 16 years (10.3 to 19.9). The mean age of the surviving patients at the time of operation was 41.3 years (26.0 to 49.0). Of these, eight have undergone revision of their acetabular component for aseptic loosening. None of the femoral components has had revision for aseptic loosening giving a survival rate of 100% at 16 years (95% confidence interval 89% to 100%).

The Furlong hydroxyapatite-ceramic-coated femoral component gives excellent long-term survival in young and active patients.

The design of the Charnley total hip replacement follows the principle of low frictional torque. It is based on the largest possible difference between the radius of the femoral head and that of the outer aspect of the acetabular component. The aim is to protect the bone-cement interface by movement taking place at the smaller radius, the articulation. This is achieved in clinical practice by a 22.225 mm diameter head articulating with a 40 mm or 43 mm diameter acetabular component of ultra-high molecular weight polyethylene.

We compared the incidence of aseptic loosening of acetabular components with an outer diameter of 40 mm and 43 mm at comparable depths of penetration with a mean follow-up of 17 years (1 to 40).

In cases with no measurable wear none of the acetabular components were loose. With increasing acetabular penetration there was an increased incidence of aseptic loosening which reflected the difference in the external radii, with 1.5% at 1 mm, 8.8% at 2 mm, 9.7% at 3 mm and 9.6% at 4 mm of penetration in favour of the larger 43 mm acetabular component.

Our findings support the Charnley principle of low frictional torque. The level of the benefit is in keeping with the predicted values.

It has been suggested that the wear of ultra-high molecular weight polyethylene (UHMWPE) in total hip replacement is substantially reduced when the femoral head is ceramic rather than metal. However, studies of alumina and zirconia ceramic femoral heads on the penetration of an UHMWPE liner in vivo have given conflicting results.

The purpose of this study was to examine the surface characteristics of 30 alumina and 24 zirconia ceramic femoral heads and to identify any phase transformation in the zirconia heads. We also studied the penetration rate of alumina and zirconia heads into contemporary UHMWPE liners. The alumina heads had been implanted for a mean of 11.3 years (8.1 to 16.2) and zirconia heads for a mean of 9.8 years (7.5 to 15).

The mean surface roughness values of the explanted alumina heads (Ra 40.12 nm and Rpm 578.34 nm) were similar to those for the explanted zirconia heads (Ra 36.21 nm and Rpm 607.34 nm). The mean value of the monoclinic phase of two control zirconia heads was 1% (0.8% to 1.5%) and 1.2% (0.9% to 1.3%), respectively. The mean value of the monoclinic phase of 24 explanted zirconia heads was 7.3% (1% to 26%).

In the alumina group, the mean linear penetration rate of the UMWPE liner was 0.10 mm/yr (0.09 to 0.12) in hips with low Ra and Rpm values (13.22 nm and 85.91 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.13 mm/yr (0.07 to 0.23) in hips with high Ra and Rpm values (198.72 nm and 1329 nm, respectively). This difference was significant (p = 0.041).

In the zirconia head group, the mean linear penetration rate of the UHMWPE liner was 0.09 mm/yr (0.07 to 0.14) in hips with low Ra and Rpm values (12.78 nm and 92.99 nm, respectively). The mean linear penetration rate of the UHMWPE liner was 0.12 mm/yr (0.08 to 0.22) in hips with high Ra and Rpm values (199.21 nm and 1381 nm, respectively). This difference was significant (p = 0.039).

The explanted zirconia heads which had a minimal phase transformation had similar surface roughness and a similar penetration rate of UHMWPE liner as the explanted alumina head.

This study reviewed the results of a cementless anatomical femoral component to give immediate post-operative stability, and with a narrow distal section in order not to contact the femoral cortex in the diaphysis, ensuring exclusively metaphyseal loading.

A total of 471 patients (601 hips) who had a total hip replacement between March 1995 and February 2002 were included in the study. There were 297 men and 174 women. The mean age at the time of operation was 52.7 years (28 to 63). Clinical and radiological evaluation were performed at each follow-up. Bone densitometry was carried out on all patients two weeks after operation and at the final follow-up examination. The mean follow-up was 8.8 years (5 to 12).

The mean pre-operative Harris hip score was 41 points (16 to 54), which improved to a mean of 96 (68 to 100) at the final follow-up. No patient complained of thigh pain at any stage. No acetabular or femoral osteolysis was observed and no hip required revision for aseptic loosening of either component. Deep infection occurred in two hips (0.3%) which required revision. One hip (0.2%) required revision of the acetabular component for recurrent dislocation. Bone mineral densitometry revealed a minimal bone loss in the proximal femur.

This cementless anatomical femoral component with metaphyseal loading but without distal fixation produced satisfactory fixation and encourages proximal femoral loading.

We studied 33 third generation, alumina ceramic-on-ceramic bearings retrieved from cementless total hip replacements after more than six months in situ. Wear volume was measured with a Roundtest machine, and acetabular orientation from the anteroposterior pelvic radiograph. The overall median early wear rate was 0.1 mm³/yr for the femoral heads, and 0.04 mm³/yr for the acetabular liners. We then excluded hips where the components had migrated. In this stable subgroup of 22 bearings, those with an acetabular anteversion of < 15° (seven femoral heads) had a median femoral head wear rate of 1.2 mm³/yr, compared with 0 mm³/yr for those with an anteversion of ≥15° (15 femoral heads, p < 0.001). Even under edge loading, wear volumes with ceramic-on-ceramic bearings are small in comparison to other bearing materials. Low acetabular anteversion is associated with greater wear.

We performed 52 total hip replacements in 52 patients using a cementless acetabular component combined with a circumferential osteotomy of the medial acetabular wall for the late sequelae of childhood septic arthritis of the hip. The mean age of the patients at operation was 44.5 years (22 to 66) and the mean follow-up was 7.8 years (5 to 11.8). The mean improvement in the Harris Hip Score was 29.6 points (19 to 51) at final follow-up. The mean cover of the acetabular component was 98.5% (87.8% to 100%). The medial acetabular wall was preserved with a mean thickness of 8.3 mm (1.7 to 17.4) and the mean length of abductor lever arm increased from 43.4 mm (19.1 to 62) to 54.2 mm (36.5 to 68.6). One acetabular component was revised for loosening and osteolysis 4.5 years postoperatively, and one had radiolucent lines in all acetabular zones at final review. Kaplan-Meier survival was 94.2% (95% confidence interval 85.8% to 100%) at 7.3 years, with revision or radiological loosening as an end-point when two hips were at risk.

A cementless acetabular component combined with circumferential medial acetabular wall osteotomy provides favourable results for acetabular reconstruction in patients who present with late sequelae of childhood septic hip arthritis.

We have developed a CT-based navigation system using infrared light-emitting diode markers and an optical camera. We used this system to perform cementless total hip replacement using a ceramic-on-ceramic bearing couple in 53 patients (60 hips) between 1998 and 2001. We reviewed 52 patients (59 hips) at a mean of six years (5 to 8) postoperatively. The mid-term results of total hip replacement using navigation were compared with those of 91 patients (111 hips) who underwent this procedure using the same implants, during the same period, without navigation. There were no significant differences in age, gender, diagnosis, height, weight, body mass index, or pre-operative clinical score between the two groups. The operation time was significantly longer where navigation was used, but there was no significant difference in blood loss or navigation-related complications. With navigation, the acetabular components were placed within the safe zone defined by Lewinnek, while without, 31 of the 111 components were placed outside this zone. There was no significant difference in the Merle d’Aubigne and Postel hip score at the final follow-up. However, hips treated without navigation had a higher rate of dislocation. Revision was performed in two cases undertaken without navigation, one for aseptic acetabular loosening and one for fracture of a ceramic liner, both of which showed evidence of neck impingement on the liner. A further five cases undertaken without navigation showed erosion of the posterior aspect of the neck of the femoral component on the lateral radiographs. These seven impingement-related mechanical problems correlated with malorientation of the acetabular component. There were no such mechanical problems in the navigated group.

We conclude that CT-based navigation increased the precision of orientation of the acetabular component and control of limb length in total hip replacement, without navigation-related complications. It also reduced the rate of dislocation and mechanical problems related to impingement.

Our aim in this prospective study was to compare the bone mineral density (BMD) around cementless acetabular and femoral components which were identical in geometry and had the same alumina modular femoral head, but differed in regard to the material of the acetabular liners (alumina ceramic or polyethylene) in 50 patients (100 hips) who had undergone bilateral simultaneous primary total hip replacement. Dual energy X-ray absorptiometry scans of the pelvis and proximal femur were obtained at one week, at one year, and annually thereafter during the five-year period of the study.

At the final follow-up, the mean BMD had increased significantly in each group in acetabular zone I of DeLee and Charnley (20% (15% to 26%), p = 0.003), but had decreased in acetabular zone II (24% (18% to 36%) in the alumina group and 25% (17% to 31%) in the polyethylene group, p = 0.001). There was an increase in the mean BMD in zone III of 2% (0.8% to 3.2%) in the alumina group and 1% (0.6% to 2.2%) in the polyethylene group (p = 0.315). There was a decrease in the mean BMD in the calcar region (femoral zone 7) of 15% (8% to 24%) in the alumina group and 14% (6% to 23%) in the polyethylene group (p < 0.001). The mean bone loss in femoral zone 1 of Gruen et al was 2% (1.1% to 3.1%) in the alumina group and 3% (1.3% to 4.3%) in the polyethylene group (p = 0.03), and in femoral zone 6, the mean bone loss was 15% (9% to 27%) in the alumina group and 14% (11% to 29%) in the polyethylene group compared with baseline values. There was an increase in the mean BMD on the final scans in femoral zones 2 (p = 0.04), 3 (p = 0.04), 4 (p = 0.12) and 5 (p = 0.049) in both groups.

There was thus no significant difference in the bone remodelling of the acetabulum and femur five years after total hip replacement in those two groups where the only difference was in the acetabular liner.