Aims. Highly cross-linked polyethylene (HXLPE) has greatly improved the durability of total hip arthroplasty (THA) in young patients because of its improved wear characteristics. Few studies have followed this population into the second decade, and therefore the purpose of this investigation was to evaluate the clinical outcome for THA patients 50 years of age and younger at a minimum of 15 years postoperatively. The second purpose was to evaluate the radiological findings secondary to wear or mechanical failure of the implant. Methods. Between October 1999 and December 2005, 105 THAs were performed in 95 patients (53 female, 42 male) aged 50 years and younger (mean 42 years (20 to 50)). There were 87 patients (96 hips) that were followed for a minimum of 15 years (mean 17.3 years (15 to 21)) for analysis. Posterior approach was used with cementless fixation with a median head size of 28 mm. HXLPE was the acetabular bearing for all hips. Radiographs were evaluated for polyethylene wear, radiolucent lines, and osteolysis. Results. Clinical outcomes showed significant improvement of mean Harris Hip Scores from 52.8 (SD 13.5) preoperatively to 94.8 (SD 7.6) postoperatively. One hip was revised for recurrent instability, and there were no infections. No hips were revised for mechanical loosening or osteolysis. Mean polyethylene linear wear was 0.04 mm/year and volumetric wear was 6.22 mm. 3. /year, with no significant differences between head size or material. Osteolysis was not present in any of the hips. Conclusion. The use of HXLPE in THA for patients aged 50 years and younger has performed exceptionally well without evidence of significant wear causing mechanical loosening or necessitating revision. The radiolucent lines of the acetabular component must be followed to determine the prognostic significance. This investigation represents the longest clinical follow-up of a large, consecutive cohort of patients aged 50 years or younger with THA using HXLPE. This long-term analysis found negligible polyethylene wear, no incidence of aseptic loosening, and excellent clinical outcomes at and beyond 15 years of follow-up. Cite this article: Bone Joint J 2021;103-B(7 Supple B):78–83

Osteolysis remains a common reason for revision after total hip arthroplasty (THA). For osteolysis associated with loose cups, revision is indicated. For osteolysis around a well-fixed cup, the decision is more controversial. The data available data support retention of the cupwith lesional treatment, working through screw holes and access channels for debridement and grafting. The choice of graft material to fill defects, if any, remains controversial. Several studies demonstrate good survivorship with cup retention strategies. Complete revision allows more complete debridement of the lesion and better graft fill, and allows implantation of a modern cup, typically with a full line of liners and bearing surfaces available. Additionally, revision allows fine tuning of the orientation of the cup, which may be advantageous for optimising hip stability. The author prefers to retain a well-fixed cup if it meets the following criteria: it is well-fixed to intra-operative testing, it is well-positioned, it is of sufficient size to allow insertion of a new liner with a reasonable head size, new liners are available, and the hip is stable to intra-operative trialing after liner insertion

Introduction. Periprosthetic osteolysis resulting in aseptic loosening is a leading cause for total hip arthroplasty (THA) failure. Individuals vary in their susceptibility to osteolysis, and it is thought that heritable factors contribute to this variation. We conducted two genome-wide association studies to identify genetic risk loci associated with osteolysis and genetic risk loci associated with time to prosthesis failure due to osteolysis. Patients/Materials & Methods. The Norway cohort comprised 2,624 subjects after THA recruited from the Norwegian Arthroplasty Registry, 779 with revision surgery for osteolysis. The UK cohort comprised 890 subjects recruited from hospitals in the north of England, 317 with radiographic evidence or revision surgery for osteolysis. All subjects had received a fully cemented or hybrid THA using small-diameter metal or ceramic-on-conventional polyethylene bearing. Osteolysis susceptibility case-control analyses and quantitative trait analyses for time to prosthesis failure were undertaken after genome-wide genotyping. Finally, a meta-analysis of the discovery datasets was undertaken. Results. Genome-wide association analysis identified 4 and 11 independent suggestive genetic signals for osteolysis susceptibility at P≤5×10. −6. in the Norwegian and UK cohorts, respectively. Following meta-analysis, 5 independent genetic signals showed suggestive association with osteolysis at P≤5×10. −6. , with the strongest comprising 18 correlated variants on chromosome 7 (lead signal rs850092, Figure 1, p=1.13×10. −6. ). Genome-wide quantitative trait analysis in cases only showed a total of 5 and 9 independent genetic signals for time to prosthesis failure at P≤5×10. −6. , respectively. Following meta-analysis, 11 independent genetic signals showed suggestive evidence of association with time to failure at P≤5×10. −6. , with the largest association block comprising 174 correlated variants in chromosome 15 (lead signal rs10507055, Figure 2, p=1.40×10. −7. ). Discussion. These studies provide the first genome-wide insights into the heritable biology of osteolysis, a major complication of joint replacement surgery. Although there were no dominant signals of genome-wide significance, we find replicating evidence for several independent genetic loci both for osteolysis susceptibility and time to prosthesis failure at P≤5×10. −6. , consistent with the complex aetiology of the disease. Conclusion. The heritable contribution to osteolysis is modest. The identified genetic loci may however provide novel avenues for therapy development in this condition. For any figures and tables, please contact the authors directly

We reviewed 249 consecutive Charnley primary low-friction arthroplasties in 191 patients performed by one surgeon using a transtrochanteric approach at a minimum follow-up of ten years. Of these, 37 hips in 32 patients showed osteolysis and were compared with 41 hips in 37 matched patients with no osteolysis. We assessed in each case the wear rate, stability of the prosthesis, acetabular angle, socket angle, thickness of the acetabular and femoral cement mantle, canal flare index, femoral score, stem alignment, implant:canal ratio and stem:canal ratio. We found that a high rate of wear, component instability and osteolysis were associated. Osteolysis was three times more common in men than in women. Factors which reduced osteolysis were cement mantles of 6 mm at the acetabulum and of 3 mm in all zones of the femur, a stem:canal ratio of 60% to 70% and an implant:canal ratio of over 99%. The overall incidence of osteolysis was 14.9% but when these technical criteria were met, the incidence was 5.2%. This suggests that careful technique can dramatically reduce the risk of this complication

Isolated liner exchange with highly crosslinked polyethylene (HXLPE) is an option to address polyethylene wear and osteolysis after total hip arthroplasty (THA). The liner can be fixed with either the original locking mechanism or cemented into the acetabular cup. Whether the method used for fixation of HXLPE liner has any bearing on the outcomes 10 to 15 years after surgery is still unclear.

Data for all patients who had undergone isolated liner exchange surgery with HXLPE in our institution between August 2000 and January 2015 were retrieved. Patients were classified according to the locking mechanism used (original locking mechanism or cemented). Survivorship and revision rates were compared among different subgroups. A total of 86 isolated liner exchanges were performed and patients had a mean duration of follow-up of 13 years (range, 5 to 22). 50 patients had the new liner cemented and the other 36 patients used the original locking mechanism.

20 patients (23.3%) had complications, with dislocation being the most common (7). 10 of them (12.6%) required re-revision surgery. Overall estimated mean survivorship was 19.2 years. There was no significant difference in the re-revision rate between original locking mechanism (11.1%) and cementation (12.0%) for the fixation of HXLPE (p=0.899). Using the Kaplan-Meier survival analysis, the revision-free survival of HXLPE fixed with original locking mechanism and cementation were 94.1% and 93.2%, respectively, at 10 years, and were 84.7% and 81.3%, respectively, at 20 years (p=0.840).

The re-revision rate and the revision-free survival of liner exchange surgery using HXLPE liner were not affected by the fixation technique used. Both cementing a HXLPE liner or using the original locking mechanism were associated with good survivorship at 13 years follow up.

Aims. Osteolysis, secondary to local and systemic physiological effects, is a major challenge in total hip arthroplasty (THA). While osteolytic defects are commonly observed in long-term follow-up, how such lesions alter the distribution of stress is unclear. The aim of this study was to quantitatively describe the biomechanical implication of such lesions by performing subject-specific finite-element (FE) analysis on patients with osteolysis after THA. Patients and Methods. A total of 22 hemipelvis FE models were constructed in order to assess the transfer of load in 11 patients with osteolysis around the acetabular component of a THA during slow walking and a fall onto the side. There were nine men and two women. Their mean age was 69 years (55 to 81) at final follow-up. Changes in peak stress values and loads to fracture in the presence of the osteolytic defects were measured. Results. The von Mises stresses were increased in models of those with and those without defects for both loading scenarios. Although some regions showed increases in stress values of up to 100%, there was only a moderate 11.2% increase in von Mises stress in the series as a whole. The site of fracture changed in some models with lowering of the load to fracture by 500 N. The most common site of fracture was the pubic ramus. This was more frequent in models with larger defects. Conclusion. We conclude that cancellous defects cause increases in stress within cortical structures. However, these are likely to lead to a modest decrease in the load to fracture if the defect is large (> 20cm. 3. ) or if the patient is small with thin cortical structures and low bone mineral density. Cite this article: Bone Joint J 2018;100-B:1455–62

In a recent phase 2 superiority clinical trial we demonstrated that a single dose of 60mg of the human monoclonal antibody denosumab inhibits osteolytic lesion activity in patients undergoing revision total hip arthroplasty (THA), demonstrating proof of biological efficacy for this clinical application. Here, we examined the effect that denosumab has on disease biology at the osteolysis tissue level.

Osteolytic tissue taken from the prosthesis-bone lesion interface at revision surgery in patients with osteolysis (n=10 participants that had received a single 60 mg dose of denosumab 8 weeks prior to revision surgery and n=10 that had received placebo) was examined for total genetic message activity and protein levels using whole genome sequencing and mass spectrometry, respectively.

The top five upregulated enriched pathways with denosumab treatment included inflammatory response, myeloid cell activation, myeloid leukocyte migration, neutrophil and granulocyte activation (p<6.26 × 10⁻²⁸). Cell morphogenesis was amongst the most downregulated pathways (p<3.42 ×10⁻²³). Finally, comparison of the trial mRNA and protein data versus mouse single cell RNA sequencing data of the same pathway blockade in mouse tibia showed the same direction of effect, suggesting that giving the drug causes then cells responsible for osteolysis to disperse into a more immature form (128 of 189 genes (z=4.87, P<0.0001) disease and functional pathways at the mRNA level and 10 of 11 (z=2.72, P=0.0065) at the protein level).

In this first-in-man study we identify multiple genes and pathways within periprosthetic osteolysis tissue that are affected by denosumab treatment. The dominant pathways involved upregulation of innate inflammatory signaling and downregulation of cell morphogenesis. We also found enrichment of similar disease and functional pathways at both the mRNA and protein levels versus mRNA pathway enrichment found in mouse osteomorphs. These data provide the first human data of the mechanistic effect of denosumab treatment on inflammatory osteolytic lesion activity after joint replacement that is necessary to support its clinical application.

∗Winner of The Bone & Joint Journal prize∗

Aims

Head-taper corrosion is a cause of failure in total hip arthroplasty (THA). Recent reports have described an increasing number of V40 taper failures with adverse local tissue reaction (ALTR). However, the real incidence of V40 taper damage and its cause remain unknown. The aim of this study was to evaluate the long-term incidence of ALTR in a consecutive series of THAs using a V40 taper and identify potentially related factors.

Aims

The aim of this study was to evaluate the performance of first-generation annealed highly cross-linked polyethylene (HXLPE) in cementless total hip arthroplasty (THA).

Aims

Large-diameter metal-on-metal (MoM) total hip arthroplasty (THA) has demonstrated unexpected high failure rates and pseudotumour formation. The purpose of this prospective cohort study is to report ten-year results in order to establish revision rate, prevalence of pseudotumour formation, and relation with whole blood cobalt levels.

Introduction

Aseptic loosening, the clinical endpoint of osteolysis, remains the leading cause of total hip arthroplasty (THA) failure, and is caused by a host response to wear debris that varies between individuals. Although several candidate gene studies have identified loci associated with osteolysis susceptibility, there have been no systematic studies at genome-wide level. We aimed to identify risk loci associated with osteolysis by conducting a genome-wide association study.

We evaluated (1) wear rate, (2) prevalence and volume of osteolysis using 3D-CT scan, (3) other bearing-related complications, (4) HHS and survivorship free from revision at 15 years after THA using first-generation XLPE (1G XLPE).

One-hundred sixty THAs were evaluated regarding bearing-related complication, HHS and survivorship. Among them, 112 hips underwent 3D-CT to analyze wear rate and osteolysis. All THAs were performed by single surgeon using cup of identical design, a 28-mm metal head and 1G XLPE (10 Mrad). Average age were 57 years and mean follow-up was 15.2 years. 3D-CT scan was performed at average of 13.0 years. Clinical evaluation included HHS and radiographic analysis was performed regarding stem alignment, cup anteversion and inclination angle, component stability, wear rate and osteolysis. Wear was measured using digital software. The prevalence and volume of osteolysis were also evaluated. Complications included XLPE dissociation/rim fracture, dislocation, periprosthetic fracture, infection, HO and any revision. Survivorship free from revision at 15 years was estimated.

Average inclination and anteversion angle of cups were 40.7° and 20.6°. Mean stem alignment was 0.1° valgus. Average bedding-in and annual wear rate wear rate was 0.085 mm and 0.025 mm/yr. Eleven hips (10%) demonstrated osteolysis; pelvic osteolysis with average volume of 1.4 cm³ in six and femoral osteolysis with mean size of 0.4 cm² in seven hips. Of 160 THAs, 5 hips (3%) dislocated. Overall, bearing-related complications occurred in 16 hips (10%). Other complications included postoperative periprosthetic fracture in 4 (3%), infection and HO in 3 hips, respectively. No hip demonstrated loosening, XLPE rim fracture/dissociation. Seven THAs (4%) were revised; recurrent dislocation in 5 and periprosthetic joint infection in 2 hips. Average HHS at last follow-up improved from 47.7 preoperatively to 91.2 points (p<0.001). Estimated survivorship free from revision at 15 years was 95.6 %.

THA using 1G XLPE demonstrated low wear rate as well as low incidence of osteolysis at average follow-up of fifteen years. Longer-term studies will be necessary to determine if XLPE will continue to demonstrate this improved osteolysis characteristics.

Now that periprosthetic osteolysis is under control, analyzing how it was overcome has substantial value. What can we learn about how to attack the next enigma? There were six important generic drivers leading to that success:

Surmounting the failure to recognize its full nature. Why was it that the lapse between the first case and the publication of the article called “cement disease” was three decades? In part, because the concept of “cement disease” was simultaneously ingenious, essential, incomplete and misleading.

Understanding “biology beyond the histology.” Histology assured us that this destruction process was not malignant but well beyond that was discovery of the novel and exquisite understanding of the molecular biology.

The importance of multiple parallel approaches. The detailed molecular biology suggested that a pharmacologic prophylaxis should exist, but none was ever found. Of the three possible alternate bearings, the most likely (metal-on-metal) failed badly and the least likely (metal-on-polyethylene) succeeded.

The critical role of “beyond luck.” It is essential to understand more fully that serendipity nearly always follows Pasteur's motto that “chance favors only the prepared mind.”

The irreplaceable role of persistence. This is almost a homily.

The unavoidable requirement of risk-taking. Forty years of metal-on-metal THA without pseudotumors provided no protection against its current ravages.

Introduction

Severe osteolysis of the femur secondary to aseptic loosening in hip arthroplasty, remains a difficult revision scenario. Multiple techniques have been developed to aid the surgeon, including restoration of bone stock with impaction bone grafting or strut allografts, various distal fixation prostheses and mega-prostheses. Cemented femoral components, with integration of the cement into the cavitations, has largely fallen out of favour. We examined the long-term outcomes with this technique.

Aims

We previously reported the long-term results of the cementless Duraloc-Profile total hip arthroplasty (THA) system in a 12- to 15-year follow-up study. In this paper, we provide an update on the clinical and radiological results of a previously reported cohort of patients at 23 to 26 years´ follow-up.

A total of 219 hips in 192 patients aged between 18 and 65 years were randomised to 28-mm metal-on-metal uncemented total hip replacements (THRs, 107 hips) or hybrid hip resurfacing (HR, 112 hips). At a mean follow-up of eight years (6.6 to 9.3) there was no significant difference between the THR and HR groups regarding rate of revision (4.0% (4 of 99) vs 5.8% (6 of 104), p = 0.569) or re-operation rates without revision (5.1% (5 of 99) vs 2.9% (3 of 104), p = 0.428). In the THR group one recurrent dislocation, two late deep infections and one peri-prosthetic fracture required revision, whereas in the HR group five patients underwent revision for femoral head loosening and one for adverse reaction to metal debris. The mean University of California, Los Angeles activity scores were significantly higher in HR (7.5 (sd 1.7) vs 6.9 (sd 1.7), p = 0.035), but similar mean Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained (5.8 (sd 9.5) in HR vs 5.1 (sd 8.9) in THR, p = 0.615) at the last follow-up. Osteolysis was found in 30 of 81 THR patients (37.4%), mostly in the proximal femur, compared with two of 83 HR patients (2.4%) (p < 0.001). At five years the mean metal ion levels were < 2.5 μg/l for cobalt and chromium in both groups; only titanium was significantly higher in the HR group (p = 0.001). Although revision rates and functional scores were similar in both groups at mid-term, long-term survival analysis is necessary to determine whether one procedure is more advantageous than the other.

Cite this article: Bone Joint J 2013;95-B:1464–73.

There are no recent studies comparing cable with wire for the fixation of osteotomies or fractures in total hip replacement (THR). Our objective was to evaluate the five-year clinical and radiological outcomes and complication rates of the two techniques. We undertook a review including all primary and revision THRs performed in one hospital between 1996 and 2005 using cable or wire fixation. Clinical and radiological evaluation was performed five years post-operatively. Cables were used in 51 THRs and wires in 126, and of these, 36 THRs with cable (71%) and 101 with wire (80%) were evaluated at follow-up. The five-year radiographs available for 33 cable and 91 wire THRs revealed rates of breakage of fixation of 12 of 33 (36%) and 42 of 91 (46%), respectively. With cable there was a significantly higher risk of metal debris (68% vs 9%; adjusted relative risk (RR) 6.6; 95% confidence interval (CI) 3.0 to 14.1), nonunion (36% vs 21%; adjusted RR 2.0; 95% CI 1.0 to 3.9) and osteolysis around the material, acetabulum or femur (61% vs 19%; adjusted RR 3.9; 95% CI 2.3 to 6.5). Cable breakage increased the risk of osteolysis to 83%. There was a trend towards foreign-body reaction and increased infection with cables. Clinical results did not differ between the groups.

In conclusion, we found a higher incidence of complications and a trend towards increased infection and foreign-body reaction with the use of cables.

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.

Aims

The stability of cementless acetabular components is an important factor for surgical planning in the treatment of patients with pelvic osteolysis after total hip arthroplasty (THA). However, the methods for determining the stability of the acetabular component from pre-operative radiographs remain controversial. Our aim was to develop a scoring system to help in the assessment of the stability of the acetabular component under these circumstances.

We evaluated the outcome of 41 consecutive Charnley low-friction arthroplasties (LFAs) performed by a single surgeon in 28 patients aged ≤ 35 years at operation between 23 and 36 years previously. There were 20 women and eight men with a mean age of 32 years (23 to 35) at surgery. Two patients (three hips) were lost to follow-up at 12 and 17 years post-operatively, respectively, and one patient (one hip) died at 13 years post-operatively. These patients were excluded from the final evaluation. The survival rate of the acetabular components was 92.7% (95% confidence interval (CI) 88.7 to 96.7) at ten years, 67.1% (95% CI 59.75 to 74.45) at 20 years and 53.2% (95% CI 45.3 to 61.1) at 25 years. For the femoral component the survival was 95.1% (95% CI 91.8 to 98.5) at ten years, 77.1% (95% CI 73.9 to 80.3) at 20 years and 68.2% (95% CI 60.7 to 75.8) at 25 years. The results indicate that the Charnley LFA remains a reasonable choice in the treatment of young patients and can serve for comparison with newer techniques and implants.

Cite this article: Bone Joint J 2013;95-B:1052–6.