Effect of Bearing Surface on Survival of Cementless and Hybrid Total Hip Arthroplasty: Study of Data in the National Joint Registry for England, Wales, Northern Ireland and the Isle of Man

Why Are Contemporary Primary Ceramic-on-Highly Crosslinked Polyethylene Total Hip Arthroplasties Failing? An Analysis of Over 5,500 Cases

BACKGROUND

Ceramic-on-highly crosslinked polyethylene (HXLPE) has become the most common bearing surface utilized in primary total hip arthroplasty (THA). The purpose of this study was to determine the implant survivorship and clinical outcomes of THAs with ceramic-on-HXLPE in a large single-institutional series.

METHODS

We identified 5,536 primary THAs performed from 2007 to 2017 using a ceramic-on-HXLPE bearing through our total joint registry. The mean age was 60 years, 51% were women, and the mean body mass index was 30. A cementless femoral component was used in 98% of cases, and a head size of ≥ 36 was used in 75%. Kaplan-Meier survivorship analyses were completed to assess survivorship free of any revision or reoperation. Clinical outcomes were assessed via Harris Hip Score. The mean follow-up was four years.

RESULTS

The 5-year survivorship free of any revision was 97%. The most common indications for revision were dislocation (41 hips), periprosthetic joint infection (39 hips), and periprosthetic femur fracture (18 hips). The 5-year survivorship free of any reoperation was 96%. There were an additional 70 reoperations, with the most common indications being wound dehiscence (32 hips), iliopsoas impingement (11 hips), and periprosthetic femur fracture (11 hips). There were only two bearing surface failures: one HXLPE liner fractured and one dissociated. There were no ceramic head fractures or failures. The mean Harris Hip Score increased from 57 to 92 (P < 0.0001).

CONCLUSIONS

In over 5,500 THAs completed with modern ceramic-on-HXLPE bearings, failures of the bearing surface were nearly eliminated at midterm follow-up, and overall 5-year survivorship free of revision was excellent. Dislocation, periprosthetic joint infection, and periprosthetic femur fracture were the most common causes of failure. As bearing surfaces have evolved, traditional failure mechanisms such as polyethylene wear, corrosion and metal reactions, and ceramic fractures have become nearly extinct.

LEVEL OF EVIDENCE

III (Case-Control Study), Therapeutic.

Ceramic-on-ceramic vs metal-on-crosslink polyethylene in a fully hydroxyapatite-coated total hip arthroplasty: Survivorship, complications and long-term results

Background

Few studies compare complications and results in ceramic-ceramic (CeCe) vs metal-on-crosslink polyethylene (Me-XLPE) hip prosthesis.

Methods

Prospective, non-randomized, observational analysis of 2 series of hydroxyapatite-coated Furlong Active implanted with identical protocol by 1 surgeon in 1 hospital from 2006 to 2014.

Bearing surface

CeCe (Biolox Forte/Delta) in 35 cases of 53.7 ± 10.6 years (25-69) (21 males, 60 %), Me-XLPE in 65 of 69.0 ± 8.9 years (42-81) (36 males, 55 %); age was different (p < 0.00001), but not sex (p = 0.6565). Head diameter: 28 mm in 19, 32 mm in 9 and 36 mm in 7 CeCe hips; 28 mm in 63, 32 mm in 1 and 36 mm in 1 Me-XLPe hips.

Follow-up

10.5 ± 3.1 years (1-15) in ceramic, 9.8 ± 3.8 years (2-15) in Me-XLPE.

Results

Survivorship without additional surgery or closed reduction at 15 years: 91.0 % in ceramic, 83.8 % in Me-XLPE joints. Survivorship without component exchange at 15 years: 93.9 % in ceramic, 93.6 % in Me-XLPE joints.

Complications

CeCe joints suffered 2 infections, 1 isolated dislocation, and 1 Vancouver-C fracture. Me-XLPE joints presented 2 infections (p = 0.6101), 5 isolated (p = 0.6621) and 2 recurrent dislocations (p = 0.5454), and 4 Vancouver-B fractures (p = 0.6548).At final follow-up, Harris Hip Score averaged 93.2 ± 13.7 (23-100) in ceramic and 94.3 ± 8.7 (65-100) in XLPE joints (p = 0.64552).Measured radiographic wear reached 0.06 ± 0.38 mm (0-1.5) (0.0057 mm/year) in CeCe and 0.16 ± 0.5 mm (0-2) (0.0163 mm/year) in Me-XLPE (p = 0.30302). At final radiographic follow-up, osteolysis was present in 8 Charnley-De Lee zones (6 patients) (17 %) of ceramic cups and in 25 zones (15 patients) (23 %) of XLPE cups (p = 0.980127).

Conclusion

At 10 years follow-up, metal-XLPE and ceramic-ceramic joints in Furlong-H-A.C. Active present no significant differences in complications, clinical score, wear, acetabular osteolysis, or survivorship without component exchange.Nevertheless, survivorship without any surgery or closed reduction is different because of the high rate of dislocation in 28 mm metal-poly joints.

Polyethylene wear and cup migration of cemented total hip arthroplasty with femoral heads made of oxidized zirconium, steel, or cobalt chromium: a 10-year secondary analysis from a randomized trial using radiostereometry

BACKGROUND AND PURPOSE

We aimed to evaluate polyethylene (PE) wear, cup migration, and clinical outcome over 10 years in total hip arthroplasties (THA) using different articulations.

METHODS

 This is a secondary analysis of 150 patients randomized into 5 groups, using different articulations: Charnley/Charnley Ogee for steel and conventional polyethylene (CPE), or Spectron EF/Reflection with either CPE or highly cross linked polyethylene (XLPE) cups, paired with heads made of either cobalt-chromium (CoCr) or oxidized zirconium (OxZr). All cups were cemented. Patients underwent repeated radiostereometric analysis (RSA) measurements for up to 10 years to assess wear and migration. Clinical outcome was assessed using Harris Hip Score (HHS).

RESULTS

 After 10 years, the XLPE cups demonstrated low wear rates: 0.08 mm (95% confidence interval [CI] -0.11 to 0.26 mm) with CoCr heads and 0.06 mm (CI -0.14 to 0.26 mm) with OxZr heads, with a mean difference of 0.01 mm (CI -0.26 to 0.29 mm). In contrast, CPE cups exhibited significantly more wear: 1.35 mm (CI 1.16 to 1.55 mm) with CoCr heads and 1.68 mm (CI 1.44 to 1.92 mm) with OxZr heads, with a mean difference of 0.33 mm (CI 0.02 to 0.64 mm). The Charnley/Ogee group (CPE) showed PE wear of 0.34 mm (CI 0.12 to 0.56 mm). The CPE groups with OxZr and CoCr heads had 0.67 mm (CI 0.38 to 0.96 mm) and 0.35 mm (CI 0.09 to 0.61 mm) greater proximal migration respectively than the corresponding XLPE groups. HHS was similar across all groups.

CONCLUSION

 We found no significant advantage of OxZr over CoCr heads in reducing wear or migration. XLPE demonstrated a major reduction in wear as well as a reduction in cup migration compared with CPE. Charnley performed better than the other CPE cups in terms of PE wear and cup migration. No differences in clinical outcome were found.

Highly Cross-Linked Polyethylene in Patients 50 Years of Age and Younger: A 20-year Follow-Up Analysis

BACKGROUND

Highly cross-linked polyethylene (HXLPE) has been an excellent bearing for total hip arthroplasty (THA) due to improved wear characteristics compared to conventional materials. Patients 50 years of age or younger are at high risk for wear-related complications of their THA, and few studies have followed these patients who have HXPLE into the third decade.

METHODS

In a retrospective review of 88 consecutive THAs performed in 77 patients aged 50 years and younger (mean 41; range, 20 to 50), in which HXLPE was utilized, they were evaluated for their clinical and radiographic results at an average of 20-year follow-up (range, 18 to 24). The current study reports on longer-term follow-up from our previously published series at shorter follow-up times. Patients were categorized by femoral head material: cobalt chrome (n = 14), ceramic (n = 30), and oxidized zirconium (n = 22) and by femoral head size: 26 mm (n = 12), 28 mm (n = 46), and 32 mm (n = 8). Harris Hip Scores were collected preoperatively and at the most recent follow-up. Radiographs were evaluated for linear and volumetric wear, radiolucent lines, and osteolysis.

RESULTS

Mean Harris Hip Scores improved from 47.1 (standard deviation [SD] 8.8) preoperatively to 92.0 (SD 7.7) (P < .0001) at 20-year follow-up. There was one hip that was revised for recurrent instability, and no hip demonstrated radiographic evidence of loosening or osteolysis. The mean polyethylene linear wear rate was 0.017 (SD 0.012) mm/y, and the mean polyethylene volumetric wear rate was 3.15 (SD 2.8) mm3/year, with no significant differences based on articulation type or head size.

CONCLUSIONS

Total hip arthroplasty with HXLPE in patients ≤ 50 years of age continues to demonstrate excellent long-term clinical and radiographic outcomes with low wear characteristics at 20-year follow-up, regardless of femoral head material or size.

Revision rate in metal compared to ceramic humeral head total shoulder arthroplasty and hemiarthroplasty

Aims

Metal and ceramic humeral head bearing surfaces are available choices in anatomical shoulder arthroplasties. Wear studies have shown superior performance of ceramic heads, however comparison of clinical outcomes according to bearing surface in total shoulder arthroplasty (TSA) and hemiarthroplasty (HA) is limited. This study aimed to compare the rates of revision and reoperation following metal and ceramic humeral head TSA and HA using data from the National Joint Registry (NJR), which collects data from England, Wales, Northern Ireland, Isle of Man and the States of Guernsey.

Methods

NJR shoulder arthroplasty records were linked to Hospital Episode Statistics and the National Mortality Register. TSA and HA performed for osteoarthritis (OA) in patients with an intact rotator cuff were included. Metal and ceramic humeral head prostheses were matched within separate TSA and HA groups using propensity scores based on 12 and 11 characteristics, respectively. The primary outcome was time to first revision and the secondary outcome was non-revision reoperation.

Results

A total of 4,799 TSAs (3,578 metal, 1,221 ceramic) and 1,363 HAs (1,020 metal, 343 ceramic) were included. The rate of revision was higher for metal compared with ceramic TSA, hazard ratio (HR) 3.31 (95% confidence interval (CI) 1.67 to 6.58). At eight years, prosthesis survival for ceramic TSA was 98.7% (95% CI 97.3 to 99.4) compared with 96.4% (95% CI 95.2 to 97.3) for metal TSA. The majority of revision TSAs were for cuff insufficiency or instability/dislocation. There was no significant difference in the revision rate for ceramic compared with metal head HA (HR 1.33 (95% CI 0.76 to 2.34)). For ceramic HA, eight-year prosthetic survival was 92.8% (95% CI 86.9 to 96.1), compared with 91.6% (95% CI 89.3 to 93.5) for metal HA. The majority of revision HAs were for cuff failure.

Conclusion

The rate of all-cause revision was higher following metal compared with ceramic humeral head TSA in patients with OA and an intact rotator cuff. There was no difference in the revision rate for HA according to bearing surface.

Lower Revision Rates and Improved Stability With a Monoblock Ceramic Acetabular Cup

BACKGROUND

Monoblock ceramic cups are designed to accommodate large-diameter femoral heads. This has the potential to offer the advantages of an increased range of motion and enhanced joint stability. These features could benefit younger and high-demand patients in need of total hip arthroplasty. The aim of this study was to assess the survival rate and the reasons for revision of the DeltaMotion cup.

METHODS

Data from the AOANJRR were analyzed for all patients who had undergone a primary conventional THA performed between January 1, 2001 and December 31, 2021. Only prostheses with ceramic/ceramic, ceramic/XLPE, metal/XLPE, or CM/XLPE bearing surfaces were included. The primary outcome measure was the cumulative percent revision for all causes. Secondary outcome measures were revision for dislocation/instability, ceramic breakage, or noise. A subanalysis for cup size was also performed.

RESULTS

There were 486,946 primary conventional THA procedures undertaken for any reason. Of these, 4,033 used the DeltaMotion cup and 482,913 were modular designs. The DeltaMotion cup had the lowest CPR for all diagnoses compared to the modular bearings at all time points, had a significantly lower revision rate for prosthesis dislocation and no revisions for squeaking compared to other modular bearings. There were 175 ceramic breakages recorded in the modular bearing group and 1 ceramic breakage in the DeltaMotion group.

CONCLUSIONS

The DeltaMotion cup had a low rate of all-cause revision, and for dislocation, ceramic breakage, and noise. Although this cup is no longer manufactured, ongoing follow-up of newer monoblock ceramic cups will determine their suitability for younger and more active patients.

Long-term polyethylene wear rates and clinical outcomes of oxidized zirconium femoral heads on highly cross-linked polyethylene in total hip arthroplasty

Aims

Oxidized zirconium (OxZi) and highly cross-linked polyethylene (HXLPE) were developed to minimize wear and risk of osteolysis in total hip arthroplasty (THA). However, retrieval studies have shown that scratched femoral heads may lead to runaway wear, and few reports of long-term results have been published. The purpose of this investigation is to report minimum ten-year wear rates and clinical outcomes of THA with OxZi femoral heads on HXLPE, and to compare them with a retrospective control group of cobalt chrome (CoCr) or ceramic heads on HXLPE.

Methods

From 2003 to 2006, 108 THAs were performed on 96 patients using an OxZi head with a HXLPE liner with minimum ten-year follow-up. Harris Hip Scores (HHS) were collected preoperatively and at the most recent follow-up (mean 13.3 years). Linear and volumetric liner wear was measured on radiographs of 85 hips with a minimum ten-year follow-up (mean 14.5 years). This was compared to a retrospective control group of 45 THAs using ceramic or CoCr heads from October 1999 to February 2005, with a minimum of ten years' follow-up.

Results

Average HHS improved from 50.8 to 91.9 and 51.0 to 89.8 in the OxZi group and control group, respectively (p = 0.644), with no osteolysis in either group. Linear and volumetric wear rates in the OxZi group averaged 0.03 mm/year and 3.46 mm3/year, respectively. There was no statistically significant difference in HHS scores, nor in linear or volumetric wear rate between the groups, and no revision for any indication.

Conclusion

The radiological and clinical outcomes, and survivorship of THA with OxZi femoral heads and HXLPE liners, were excellent, and comparable to CoCr or ceramic heads at minimum ten-year follow-up. Wear rates are below what would be expected for development of osteolysis. OxZi-HXLPE is a durable bearing couple with excellent long-term outcomes.

Dynamic computational wear model of PEEK-on-XLPE bearing couple in total hip replacements

Understanding wear mechanisms is a key factor to prevent primary failures causing revision surgery in total hip replacement (THR) applications. This study introduces a wear prediction model of (Polyetheretherketone) PEEK-on-XLPE (cross-linked polyethylene) bearing couple utilized to investigate the wear mechanism under 3D-gait cycle loading over 5 million cycles (Mc). A 32-mm PEEK femoral head and 4-mm thick XLPE bearing liner with a 3-mm PEEK shell are modeled in a 3D explicit finite element modeling (FEM) program. The volumetric and linear wear rates of XLPE liner per every million cycles were predicted as 1.965 mm³/Mc, and 0.0032 mm/Mc respectively. These results are consistent with the literature. PEEK-on-XLPE bearing couple exhibits a promising wear performance used in THR application. The wear pattern evolution of the model is similar to that of conventional polyethylene liners. Therefore, PEEK could be proposed as an alternative material to the CoCr head, especially used in XLPE-bearing couples. The wear prediction model could be utilized to improve the design parameters with the aim of prolonging the life span of hip implants.

Similarly low blood metal ion levels at 10-years follow-up of total hip arthroplasties with Oxinium, CoCrMo, and stainless steel femoral heads. Data from a randomized clinical trial

The use of inert head materials such as ceramic heads has been proposed as a method of reducing wear and corrosion products from the articulating surfaces in total hip arthroplasty, as well as from the stem-head taper connection. The aim of the present study was to compare the blood metal ion levels in patients with Oxinium and CoCrMo modular femoral heads, as well as monoblock stainless steel Charnley prostheses at 10 years postoperatively. The 150 patients with osteoarthritis of the hip joint included in a randomized clinical trial were grouped according to femoral head material. One group (n = 30) had received the Charnley monoblock stainless steel stem (DePuy, UK). The other patients (n = 120) received a Spectron EF CoCrMo stem with either a 28 mm CoCrMo or Oxinium modular head (Smith & Nephew, USA). After 10 years, 38 patients had withdrawn, 19 deceased, 7 revised due to aseptic loosening and 5 revised due to infection. The 81 patients with median age of 79 years (70-91) were available for whole blood metal ion analysis. The levels of Co, Cr, Ni and Zr in the blood were generally low with all the head materials (medians <0.3 micrograms/L) and no statistical difference between the groups were found (p = .2-.8). Based on the low blood metal ion values in our study groups, no indication of severe trunnion corrosion in patients with CoCrMo heads was observed, neither was there any beneficial reduction in metal ion exposure with the Oxinium femoral heads.

Isolation and characterisation of wear debris surrounding failed total ankle replacements

Aseptic loosening and osteolysis continue to be a short- to mid-term problem for total ankle replacement (TAR) devices. The production of wear particles may contribute to poor performance, but their characteristics are not well understood. This study aimed to determine the chemical composition, size and morphology of wear particles surrounding failed TARs. A recently developed wear particle isolation method capable of isolating both high- and low-density materials was applied to 20 retrieved periprosthetic tissue samples from 15 failed TARs of three different brands. Isolated particles were imaged using ultra-high-resolution imaging and characterised manually to determine their chemical composition, size, and morphology. Six different materials were identified, which included: UHMWPE, calcium phosphate (CaP), cobalt chromium alloy (CoCr), commercially pure titanium, titanium alloy and stainless steel. Eighteen of the 20 samples contained three or more different wear particle material types. In addition to sub-micron UHMWPE particles, which were present in all samples, elongated micron-sized shards of CaP and flakes of CoCr were commonly isolated from tissues surrounding AES TARs. The mixed particles identified in this study demonstrate the existence of a complex periprosthetic environment surrounding TAR devices. The presence of such particles suggests that early failure of devices may be due in part to the multifaceted biological cascade that ensues after particle release. This study could be used to support the validation of clinically-relevant wear simulator testing, pre-clinical assessment of fixation wear and biological response studies to improve the performance of next generation ankle replacement devices. STATEMENT OF SIGNIFICANCE: Total ankle replacement devices do not perform as well as total hip and knee replacements, which is in part due to the relatively poor scientific understanding of how they fail. The excessive production of certain types of wear debris is known to contribute to joint replacement failure. This is the first study to successfully isolate and characterise high- and low-density wear particles from tissues collected from patients with a failed total ankle replacement. This article includes the chemical composition and characteristics of the wear debris generated by ankle devices, all of which may affect their performance. This research provides clinically relevant reference values and images to support the development of pre-clinical testing for future total ankle replacement designs.

Higher risk of 2-year cup revision of ceramic-on-ceramic versus ceramic-on-polyethylene bearing: analysis of 33,454 primary press-fit total hip arthroplasties registered in the Dutch Arthroplasty Register (LROI)

BACKGROUND AND PURPOSE

The influence of bearing on short-term revision in press-fit total hip arthroplasty (THA) remains under-reported. The aim of this study was to describe 2-year cup revision rates of ceramic-on-ceramic (CoC) and ceramic-on-polyethylene (CoPE).

PATIENTS AND METHODS

Primary press-fit THAs with one of the three most used cups available with both CoC or CoPE bearing recorded in the Dutch Arthroplasty Register (LROI) were included (2007-2019). Primary outcome was 2-year cup revision for all reasons. Secondary outcomes were: reasons for revision, incidence of different revision procedures and use of both bearings over time.

RESULTS

2-year Kaplan-Meier cup revision rate in 33,454 THAs (12,535 CoC; 20,919 CoPE) showed a higher rate in CoC (0.67% [95% CI, 0.54-0.81]) compared to CoPE (0.44% [95% CI, 0.34-0.54]) (p = 0.004). Correction for confounders (age, gender, cup type, head size) resulted in a hazard ratio (HR) of 0.64 [95%CI, 0.48-0.87] (p = 0.019). Reasons for cup revision differed only by more cup revision due to loosening in CoC (26.2% vs.1 3.2%) (p = 0.030). For aseptic loosening a revision rate of 0.153% [95% CI, 0.075-0.231] was seen in CoC and 0.058% [95%CI 0.019-0.097] in CoPE (p = 0.007). Correction for head size resulted in a HR of 0.475 [95% CI, 0.197-1.141] (p = 0.096). Incidence of different revision procedures did not differ between bearings. Over time the use of CoPE has increased and CoC decreased.

CONCLUSIONS

A higher 2-year cup revision rate in press-fit THA was observed in CoC compared to CoPE. Cup loosening was the only significantly different reason for revision and seen more often in CoC and mostly aseptic. Future randomised controlled trials need to confirm causality, since the early cup revision data provided has the potential to be useful when choosing the bearing in press-fit THA, when combined with other factors like bone quality and patient and implant characteristics.

Uncemented total hip arthroplasty using alumina ceramic bearings at a minimum of 14 years of follow-up

INTRODUCTION

The effectiveness of modern ceramic bearings has been well established in reducing the osteolysis associated with wear of the bearing surfaces in total hip arthroplasty (THA). However, there are limited mid- to long-term follow-up data for complications associated with ceramic bearings.

MATERIALS AND METHODS

This case series analyzed 124 consecutive primary uncemented THAs in 108 patients with a mean age of 61 years using alumina ceramic-on-alumina ceramic bearing couples. Seventy THAs (56%) were evaluated at a minimum 14 years of follow-up; the mean follow-up period was 16 ± 1 years (14-20 years). Kaplan-Meier survivorship was determined with revision surgery for any reason as the end point. Complications were recorded focusing on osteolysis, ceramic fracture, and abnormal sounds until the final follow-up. Clinical data were scored according to the Merle d'Aubigne and Postel hip score at 14 years after THA.

RESULTS

The survivorship was 93.5% (95% CI 86.7-97.0%) at 14-years postoperatively. Five patients (4.0%) underwent revision surgery due to instability or infection before 1-year postoperatively. Two patients (1.6%) underwent revision surgery due to ceramic liner fracture at 9- and 12-years postoperatively, respectively. There was no radiographic evidence of osteolysis. A total of 27 complications occurred: dislocations (n = 7/124), squeaking sounds (n = 3/124), clicking sounds (n = 6/124), ceramic liner fractures (n = 2/124), periprosthetic fractures (n = 4/124), deep infections (n = 2/124), transient sciatic nerve palsy (n = 2/124), and femoral stem breakage (n = 1/124). The Merle d'Aubigne and Postel hip score was 16.8 ± 1.4 points.

CONCLUSIONS

The survivorship analysis demonstrates the uncemented THA using alumina ceramic bearings may provide favorable clinical outcome and can offer minimal wear at a minimum 14-year follow-up. Revision surgery was mostly required due to instability and infection in the short-term, and implant breakage in the mid- to long-term.

A Ten-Year Radiostereometric Analysis of Polyethylene Wear Between Oxidized Zirconium and Cobalt Chrome Articulations in Total Hip Arthroplasty

BACKGROUND

Oxidized zirconium (OxZi) femoral heads combine the decreased abrasive properties of ceramics with the toughness of metal alloys to lower wear and increase the durability of total hip arthroplasty. The purpose of this study was to compare the 10-year polyethylene wear rates between OxZi/XLPE and cobalt chrome (CoCr)/XLPE articulations.

METHODS

A radiostereometric analysis (RSA) was performed on two cohorts of 23 patients who underwent total hip arthroplasty using either OxZi/XLPE or CoCr/XLPE at a minimum of 10-year follow-up. Cohorts were matched for age, gender, body mass index (BMI), and diagnosis. Polyethylene wear was measured using RSA to determine total and steady-state wear rates for both cohorts. Preoperative and postoperative patient-reported outcome measures (SF12, HHS, and Western Ontario and McMaster Universities Arthritis Index scores) were compared.

RESULTS

The mean total head penetration rate was found to be statistically different between the entire cohorts (OxZi 0.048 ± 0.021 mm/y, CoCr 0.035 ± 0.017 mm/y, P = .02) but not when 28-mm heads only (OxZi 0.045 ± 0.016 mm/y, CoCr 0.034 ± 0.017 mm/y, P = .066) were directly compared. The mean steady-state wear rate was not significantly different between the entire cohorts (OxZi 0.031 ± 0.021 mm/y, CoCr 0.024 ± 0.019 mm/y, P = .24) or 28-mm head cohorts (OxZi 0.028 ± 0.019 mm/y, CoCr 0.024 ± 0.019 mm/y, P = .574). Outcome measures showed no statistical difference except for the Harris Hip Score where the OxZi cohort demonstrated higher median scores.

CONCLUSION

Using RSA to evaluate the 10-year in-vivo head penetration, there was no statistically significant difference in steady-state wear rates between OxZi and CoCr articulations. Both bearing combinations demonstrated wear rates well below the threshold for osteolysis.

Oxidized zirconium versus cobalt-chrome femoral heads in total hip arthroplasty: a multicentre prospective randomized controlled trial with ten years' follow-up

AIMS

This study reports the ten-year wear rates, incidence of osteolysis, clinical outcomes, and complications of a multicentre randomized controlled trial comparing oxidized zirconium (OxZr) versus cobalt-chrome (CoCr) femoral heads with ultra-high molecular weight polyethylene (UHMWPE) and highly cross-linked polyethylene (XLPE) liners in total hip arthroplasty (THA).

METHODS

Patients undergoing primary THA were recruited from four institutions and prospectively allocated to the following treatment groups: Group A, CoCr femoral head with XLPE liner; Group B, OxZr femoral head with XLPE liner; and Group C, OxZr femoral head with UHMWPE liner. All study patients and assessors recording outcomes were blinded to the treatment groups. The outcomes of 262 study patients were analyzed at ten years' follow-up.

RESULTS

Patients in Group C were associated with increased mean liner wear rates compared to patients in Group A (0.133 mm/yr (SD 0.21) vs 0.031 mm/yr (SD 0.07), respectively; p < 0.001) and Group B (0.133 mm/yr (SD 0.21) vs 0.022 mm/yr (SD 0.05), respectively; p < 0.001) at ten years' follow-up. Patients in Group C were also associated with increased risk of osteolysis and aseptic loosening requiring revision surgery, compared with patients in Group A (7/133 vs 0/133, respectively; p = 0.007) and Group B (7/133 vs 0/135, respectively; p = 0.007). There was a non-statistically significant trend towards increased mean liner wear rates in Group A compared with Group B (0.031 mm/yr (SD 0.07) vs 0.022 mm/yr (SD 0.05), respectively; p = 0.128). All three groups were statistically comparable preoperatively and at ten years' follow-up when measuring normalized Western Ontario and McMaster Universities Osteoarthritis Index (p = 0.410), 36-Item Short Form Health Survey (p = 0.465 mental, p = 0.713 physical), and pain scale scores (p = 0.451).

CONCLUSION

The use of UHMWPE was associated with progressively increased annual liner wear rates after THA compared to XLPE. At ten years' follow-up, the group receiving UHMWPE demonstrated an increased incidence of osteolysis and aseptic loosening requiring revision surgery compared to XLPE. Femoral heads composed of OxZr were associated with trend towards reduced wear rates compared to CoCr, but this did not reach statistical significance and did not translate to any differences in osteolysis, functional outcomes, or revision surgery between the two femoral head components. Cite this article: Bone Joint J 2022;104-B(7):833-843.

Implant factors that might influence components' survival in primary total hip arthroplasty

Primary total hip arthroplasty (THA) is an invaluable surgical procedure that has revolutionised the treatment of various end-stage hip pathologies. Aseptic loosening of either acetabular cup and/or femoral stem as well as components' dislocation are well-known post-operative complications due to so many factors: environmental, surgeon, patient related, disease related or implant design. The aim of this literature review is to look at some relevant implant designs that might influence acetabular and femoral components' survival for primary cementless THA using revision for aseptic loosening and dislocation as criteria for failure. This may also assist the surgeon in making an informed choice of using appropriate implants to match the demographic and disease-specific need of the patients undergoing the surgical procedure. This review article was performed using an online literature search on relevant publications.

Using an asymmetric crosslinked polyethylene liner in primary total hip arthroplasty is associated with a lower risk of revision surgery : an analysis of the National Joint Registry

AIMS

The aim of our study was to investigate the effect of asymmetric crosslinked polyethylene liner use on the risk of revision of cementless and hybrid total hip arthroplasties (THAs).

METHODS

We undertook a registry study combining the National Joint Registry dataset with polyethylene manufacturing characteristics as supplied by the manufacturers. The primary endpoint was revision for any reason. We performed further analyses on other reasons including instability, aseptic loosening, wear, and liner dissociation. The primary analytic approach was Cox proportional hazard regression.

RESULTS

A total of 213,146 THAs were included in the analysis. Overall, 2,997 revisions were recorded, 1,569 in THAs with a flat liner and 1,428 in THAs using an asymmetric liner. Flat liner THAs had a higher risk of revision for any reason than asymmetric liner THAs when implanted through a Hardinge/anterolateral approach (hazard ratio (HR) 1.169, 95% confidence interval (CI) 1.022 to 1.337) and through a posterior approach (HR 1.122, 95% CI 1.108 to 1.346). There was no increased risk of revision for aseptic loosening when asymmetric liners were used for any surgical approach. A separate analysis of the three most frequently used crosslinked polyethylene liners was in agreement with this finding. When analyzing THAs with flat liners only, THAs implanted through a Hardinge/anterolateral approach were associated with a reduced risk of revision for instability compared to posterior approach THAs (HR 0.561 (95% CI 0.446 to 0.706)). When analyzing THAs with an asymmetric liner, there was no significant difference in the risk of revision for instability between the two approaches (HR 0.838 (95% CI 0.633 to 1.110)).

CONCLUSION

For THAs implanted through the posterior approach, the use of asymmetric liners reduces the risk of revision for instability and revision for any reason. In THAs implanted through a Hardinge/anterolateral approach, the use of an asymmetric liner was associated with a reduced risk of revision. The effect on revision for instability was less pronounced than in the posterior approach. Cite this article: Bone Joint J 2021;103-B(9):1479-1487.

Fracture of a 40-mm BIOLOX Delta Femoral Head

Ceramic bearing surfaces have gained popularity in total hip arthroplasty as a result of the favorable mechanical properties and low wear rates. Despite the recognition as an attractive articulation, problems such as ceramic head fracture persist. Smaller heads and higher body mass indices are touted as risk factors for ceramic head fracture and are often associated with antecedent trauma. We present a case report of an 83-year-old male with a body mass index of 26.7 kg/m² who suffered a fracture of a 40-mm ceramic femoral head. This occurred atraumatically 5 years from his index surgery. This patient underwent revision total hip arthroplasty which included debridement of ceramic debris and alteration of the bearing surface with femoral head and polyethylene liner exchange.

Reduced Risk of Revision with Computer-Guided Versus Non-Computer-Guided THA: An Analysis of Manufacturer-Specific Data from the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man

Computer-assisted total hip arthroplasty (THA) is known to improve implantation precision, but clinical data demonstrating an improvement in survivorship and patient-reported outcome measures (PROMs) are lacking. Our aim was to compare the risk of revision, PROMs, and patient satisfaction between cohorts who underwent THA with and without the use of computer guidance.

Methods

We used the data set and linked PROM data of the National Joint Registry of England, Wales, Northern Ireland and the Isle of Man. Our sample included THAs performed for osteoarthritis using cementless acetabular components from a single manufacturer (cementless and hybrid THAs). An additional analysis was performed limiting the sample size to cementless-only THAs. The primary end point was revision (any component) for any reason. Kaplan-Meier survivorship analysis and an adjusted Cox proportional-hazards model were used.

Results

There were 41,683 non-computer-guided and 871 (2%) computer-guided cases included in our analysis of the cementless and hybrid group. There were 943 revisions in the non-computer-guided group and 7 in the computer-guided group. The cumulative revision rate at 10 years was 3.88% (95% confidence interval [CI]: 3.59% to 4.18%) for the non-computer-guided group and 1.06% (95% CI: 0.45% to 2.76%) for the computer-guided group. The Cox proportional-hazards model yielded a hazard ratio of 0.45 (95% CI: 0.21 to 0.96; p = 0.038). In the analysis of the cementless-only group, the cumulative revision rate at 10 years was 3.99% (95% CI: 3.62% to 4.38%) and 1.20% (95% CI: 0.52% to 3.12%) for the 2 groups, respectively. The Cox proportional-hazards model yielded a hazard ratio of 0.47 (95% CI: 0.22 to 1.01; p = 0.053). There was no significant difference in the 6-month Oxford Hip Score, the EuroQol-5 Dimension (EQ-5D) and EQ-VAS (Visual Analogue Scale) scores, and patient-reported success rates. Patient satisfaction (single-item satisfaction outcome measure) was higher in the computer-guided group, but this finding was limited by a reduced number of responses.

Conclusions

In our analysis, the use of computer-guided surgery was associated with a lower rate of revision at mean follow-up of 5.6 years. This finding was upheld when the sample was restricted to cementless-only THAs. Causality cannot be inferred in view of the observational nature of the study, and additional studies are recommended to validate these findings.

Level of Evidence

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Mid-term outcomes of the R3™ delta ceramic acetabular system in total hip arthroplasty

Background

Whilst bony fixation of hip replacement has stable solutions, there remains controversy over which bearing best optimizes longevity and function. Ceramic-on-ceramic (CoC) bearing combinations are associated with lower risk of revision due to aseptic loosening and dislocation. Evidence for long-term functional outcomes of modern, 4th generation CoC bearings is limited. The aim of this study was to analyze outcomes and complications of the R3™ Acetabular System (Smith & Nephew, Inc., Cordova, TN, USA) in combination with BIOLOX® Delta ceramic femoral head in patients undergoing primary total hip arthroplasty (THA).

Methods

Between June 2009 and May 2011, 175 patients (178 hips) were enrolled into a prospective, study at 6 sites in Europe and prospectively followed-up at 3 months and 1, 3, 5, and 7 years postoperative.

Results

Total WOMAC score improved from 63 (range, 22–91) preoperative to 8 (range, 0–8) at 1-year follow-up and remained unchanged at 7-year follow-up. Modified Harris hip score improved from 45 (range, 10–87) preoperative to 83 (range, 25–100) at 3 months, 91 (range, 42–100) at 1 year, and 92 (range, 46, 100) at 7 years. UCLA Activity Rating Scale score improved from 3.3 (range, 1–8) preoperative to 6.2 (range, 2–8) at 1 year; it marginally declined to 5.8 (range, 3–8) at 7-year follow-up. There were 4 trochanteric fractures and 5 patients died of unrelated reasons. Three hips were revised (2 periprosthetic fractures and 1 subluxation). The 7-year cumulative survival rate was 98.3%.

Conclusion

Clinical and functional improvements of THA with CoC bearing are maintained at 7 years postoperative.

Trial registration

ClinicalTrials.Gov, NCT03566082, Registered 10 January 2018—retrospectively registered,