Management of geriatric acetabular fractures:Contemporary treatment strategies

Acetabular fractures in the geriatric population are typically low-energy fractures resulting from a fall from standing height.Compromised bone quality in the elderly,as well as this population’s concomitant medical comorbidities,render the management of such fractures challenging and controversial.Non-operative management remains the mainstay of treatment,although such a choice is associated with numerous and serious complications related to both the hip joint as well as the general condition of the patient.On the other hand,operatively treating acetabular fractures(e.g.,with osteosynthesis or total hip arthroplasty)is gaining popularity.Osteosynthesis can be performed with open reduction and internal fixation or with minimally invasive techniques.Total hip arthroplasty could be performed either in the acute phase combined with osteosynthesis or as a delayed procedure after a period of non-operative management or after failed osteosynthesis of the acetabulum.Regardless of the implemented treatment,orthogeriatric co-management is considered extremely crucial,and it is currently one of the pillars of a successful outcome after an acetabular fracture.

Bone graft incorporation failure with inappropriate limb load transfer can lead to aseptic acetabular loosening of metal-on-metal prosthesis: A case report

BACKGROUND Aseptic acetabular loosening can result from various factors that can be categorized into groups:patient-related,surgeon-related and implant-related.We present a case of a 63-year-old patient who at first underwent a total hip arthro-plasty(THA)using a metal-on-metal bearing due to hip arthrosis.Follow-up visits revealed no complications after the procedure.Two years after the THA,acetabular component loosening occurred due to subsequent trauma of the opposite hip,necessitating a revision THA using a ceramic-on-ceramic bearing.CASE SUMMARY We aim to illustrate a rare case where the primary reason for undergoing THA revision was not only incomplete bone graft incorporation but also improper limb load distribution.Following the revision arthroplasty,a 9-year follow-up visit revealed improvements in all evaluation measures on questionnaire compared to the state before surgery:Harris Hip Score(before surgery:15;after surgery:95),Western Ontario and McMaster Universities Arthritis Index(before surgery:96;after surgery:0),and Visual Analogue Scale(before surgery:10;after surgery:1).CONCLUSION Opposite-hip trauma caused a weight transfer to the limb after a THA procedure.This process led to a stress shielding effect,resulting in acetabular component loosening.

Roles of combined femoral and acetabular anteversion in pathological changes of hip dysplasia and hip reconstructive surgery

Combined femoral and acetabular anteversion is the sum of femoral and acetabular anteversion,representing their morphological relationship in the axial plane.Along with the increasing understanding of hip dysplasia in recent years,numerous scholars have confirmed the role of combined femoral and acetabular anteversion in the pathological changes of hip dysplasia.At present,the reconstructive surgery for hip dysplasia includes total hip replacement and redirectional hip preservation surgery.As an important surgery index,combined femoral and acetabular anteversion have a crucial role in these surgeries.Herein,we discuss the role of combined femoral and acetabular anteversion in pathological changes of hip dysplasia,total hip replacement,and redirectional hip preservation surgery.

Technical note for intraoperative determination of proper acetabular cup size in primary total hip arthroplasty

BACKGROUND Selecting the optimal size of components is crucial when performing a primary total hip arthroplasty.Implanting the accurate size of the acetabular component can occasionally be exacting,chiefly for surgeons with little experience,whilst the complications of imprecise acetabular sizing or over-reaming can be potentially devastating.AIM To assist clinicians intraoperatively with a simple and repeatable tip in elucidating the ambivalence when determining the proper acetabular component size is not straightforwardly achieved,specifically when surgeons are inexperienced or preoperative templating is unavailable.METHODS This method was employed in 263 operations in our department from June 2021 to December 2022.All operations were performed by the same team of joint reconstruction surgeons,employing a typical posterior hip approach technique.The types of acetabular shells implanted were:The Dynasty®acetabular cup system(MicroPort Orthopedics,Shanghai,China)and the R3®acetabular system(Smith&Nephew,Watford,United Kingdom),which both feature cementless press-fit design.RESULTS The mean value of all cases was calculated and collated with each other.We distinguished as oversized an implanted acetabular shell when its size was>2 mm larger than the size of the acetabular size indicator reamer(ASIR)or when the implanted shell was larger than 4 mm compared to the preoperative planned cup.The median size of the implanted acetabular shell was 52(48–54)mm,while the median size of the preoperatively planned cup was 50(48–56)mm,and the median size of the ASIR was 52(50–54)mm.The correlation coefficient between ASIR size and implanted acetabular component size exhibited a high positive correlation with r=0.719(P<0.001).Contrariwise,intraoperative ASIR measurements precisely predicted the implanted cups’size or differed by only one size(2 mm)in 245 cases.CONCLUSION In our study,we demonstrated that the size of the first acetabular reamer not entering freely in the acetabular rim corroborates the final acetabular component size to implant.This was also corresponding in the majority of the cases with conventional preoperative templating.It can be featured as a valid tool for avoiding the potentially pernicious complications of acetabular cup over-reaming and over-sizing in primary total hip arthroplasty.It is a simple and reproducible technical note useful for confirming the predicted acetabular cup size preoperatively;thus,its application could be considered routinely,even in cases where preoperative templating is unavailable.

Direct ink writing to fabricate porous acetabular cups from titanium alloy

Acetabular cups,which are among themost important implants in total hip arthroplasty,are usually made from titanium alloys with high porosity and adequate mechanical properties.The current three-dimensional(3D)printing approaches to fabricate customized acetabular cups have some inherent disadvantages such as high cost and energy consumption,residual thermal stress,and relatively low efficiency.Thus,in this work,a direct ink writing method was developed to print a cup structure at room temperature,followed by multi-step heat treatment to form microscale porous structure within the acetabular cup.Our method is facilitated by the development of a self-supporting titanium-6 aluminum-4 vanadium(Ti64)ink that is composed of Ti64 particles,bentonite yield-stress additive,ultraviolet curable polymer,and photo-initiator.The effects of Ti64 and bentonite concentrations on the rheological properties and printability of inks were systematically investigated.Moreover,the printing conditions,geometrical limitations,and maximum curing depth were explored.Finally,some complex 3D structures,including lattices with different gap distances,honeycomb with a well-defined shape,and an acetabular cup with uniformly distributed micropores,were successfully printed/fabricated to validate the effectiveness of the proposed method.

Surgical outcomes of acute acetabular transverse fracture using ilioinguinal and Stoppa approach

Objective: To compare surgical outcomes of acute acetabular transverse fracture using ilioinguinal and Stoppa approach. Methods: Twenty five patients who managed with ilioinguinal approach (group A) at a mean follow-up of (32.3±4.6) mo and 30 patients who managed with Stoppa approach (group B) at a mean follow-up of (29.7±3.8) mo were prospectively reviewed. The study was approved by the hospital ethical review committee (IRB approval no: 0189-2007). Patients were called for routine follow up and follow-up durations were set. End points of the study were: (1) blood loss was measured intraoperatively by measuring the blood loss in the suction drain and counting blood stained gauze and postoperatively by assessing hemoglobin after 6 h of surgery;(2) functional outcome was demonstrated using the Harris hip score;(3) reduction quality and radiological results were demonstrated by Matta scoring system. Results: Mean blood loss (intraoperatively +postoperatively) was (1 175.8±310.2) mL and (1 115.7±285.1) mL in patients operated with ilioinguinal and Stoppa approach, respectively. Mean operative time was (242.3±60.8) min and (198.9±50.3) min in patients operated with ilioinguinal and Stoppa approach, respectively. Functional outcome, radiological outcome and reduction quality showed no significant difference between two approaches. Complication rate was 36.0% in group A (9 patients) and 13.3% in group B (4 patients). Conclusions: Our study concludes that Stoppa approach allows less blood loss and operative time with fewer complications.

Effects of different pelvic osteotomies on acetabular morphology in developmental dysplasia of hip in children

Developmental dysplasia of hip seriously affects the health of children,and pelvic osteotomy is an important part of surgical treatment.Improving the shape of the acetabulum,preventing or delaying the progression of osteoarthritis is the ultimate goal of pelvic osteotomies.Re-directional osteotomies,reshaping osteotomies and salvage osteotomies are the three most common types of pelvic osteotomy.The influence of different pelvic osteotomy on acetabular morphology is different,and the acetabular morphology after osteotomy is closely related to the prognosis of the patients.But there lacks comparison of acetabular morphology between different pelvic osteotomies,on the basis of retrospective analysis and measurable imaging indicators,this study predicted the acetabular shape after developmental dysplasia of the hip pelvic osteotomy in order to help clinicians make reasonable and correct decisions and improve the planning and performance of pelvic osteotomy.

髂窝入路配合改良的Stoppa入路在骨盆髋臼骨折中的应用

目的探讨髂窝入路配合改良的Stoppa入路在骨盆髋臼骨折中的应用疗效。方法我科自2010年3月至2011年12月共应用该方法治疗骨盆髋臼骨折30例,骨盆骨折22例,髋臼骨折8例。骨盆骨折Tile分型C型,髋臼骨折为前柱、横行、双柱及T型。结果术后根据Matta影像学评分,骨盆骨折前后环复位满意,髋臼骨折解剖复位6例,2例复位满意,随访27例,随访平均半年。所有随访患者无钢板断裂及螺钉松动,所有随访患者均骨折愈合,但有1例患者因合并后壁骨折术中经前向后方行螺钉固定未再采取后方K-L入路,未达到解剖复位,半年后出现股骨头坏死。平均手术时间90min（75~115min）,平均出血500mL（200~750mL）。结论髂窝入路配合改良的Stoppa入路如果运用得当可代替髂腹股沟入路能解决的所有问题。该显露办法较髂腹股沟入路的损伤小,容易掌握、耗时短及并发症少,值得推广。

3D Printing Hip Prostheses Offer Accurate Reconstruction,Stable Fixation,and Functional Recovery for Revision Total Hip Arthroplasty with Complex Acetabular Bone Defect

Complicated and large acetabular bone defects present the main challenges and difficulty in the revision of total hip arthroplasty(THA).This study aimed to explore the advantages of three-dimensional(3D)printing technology in the reconstruction of such acetabular bone defects.We retrospectively analyzed the prognosis of four severe bone defects around the acetabulum in three patients who were treated using 3D printing technology.Reconstruction of bone defect by conventional methods was difficult in these patients.In this endeavor,we used radiographic methods,related computer software such as Materialise's interactive medical image control system and Siemens NX software,and actual surgical experience to estimate defect volume,prosthesis stability,and installation accuracy,respectively.Moreover,a Harris hip score was obtained to evaluate limb function.It was found that bone defects could be adequately reconstructed using a 3D printing prosthesis,and its stability was reliable.The Harris hip score indicated a very good functional recovery in all three patients.In conclusion,3D printing technology had a good therapeutic effect on both complex and large bone defects in the revision of THA.It was able to achieve good curative effects in patients with large bone defects.

Acetabular components with or without screws in total hip arthroplasty

AIM To compare the operation time, blood loss, and early outcomes of acetabular components with and without the screw.METHODS Thirty patients who underwent cementless acetabular component with or without screw and whose follow-up exceeded one year period in total hip arthroplasty were evaluated. A posterior approach was used in all surgical procedures by one experienced surgeon. Demographic data, operation time, intra-and postoperative blood loss volume, follow-up clinical score, cup migration, and osteolysis were recorded. The Kolmogorov-Smirnov test was performed for testing the normality of study data. Mann-Whitney U test was used to analyze the intergroup differences. A P-value of ≤ 0.05 was considered statistically significant.RESULTS Acetabular components were used in 16(53.3%) patients with screw and 14(46.7%) without screw. After one year of follow-up, an osteolytic lesion of 3 mm was found in only one patient in the screw group. No cup migrationwas encountered. Intra-group mean Harris hip score significantly increased, but there was no significant intergroup difference. While the mean operation time of the screw group was 121.8 min(range; 95-140), it was 102.7 min(range; 80-120) in the no-screw group, and this difference was statistically significant(P = 0.002). The mean intraoperative/postoperative, and total blood loss were 556.6 mL(range: 350-800)/423.3 mL(range: 250-600), and 983.3 mL(range: 600-1350), respectively in the screw group; and 527 mL(range: 400-700)/456 mL(range: 230-600), and 983 mL(range: 630-1250), respectively in the no-screw group. The blood loss difference between the two groups was not significant. In the screw group, the operation time was 19.1 min longer than the no-screw group, and this difference was statistically significant.CONCLUSION Acetabular components with or without screw have similar results, but the use of screw increases the operation time significantly, while not changing the blood loss volume.

Fix and replace:An emerging paradigm for treating acetabular fractures in older patients

Acetabular fractures in older patients are challenging to manage.The "fix and replace" construct may present a new paradigm for the management of these injuries.We present the current challenge of acetabular fractures in older patients.We present this in the context of the current literature.This invited editorial presents early results from our centre and the ongoing challenges are discussed.

Acetabular revisions using porous tantalum components: A retrospective study with 5-10 years follow-up

AIM To evaluate the clinical and X-ray results of acetabular components and tantalum augments in prosthetic hip revisions.METHODS Fifty-eight hip prostheses with primary failure of the acetabular component were reviewed with tantalum implants. The clinical records and X-rays of these cases were retrospectively reviewed. Bone defect evaluations were based on preoperative CT scans and classified according to Paprosky criteria of Radiolucent lines and periprosthetic gaps; implant mobilization and osteolysis were evaluated by X-ray. An ad hoc database was created and statistical analyses were performed with SPSS software(IBM SPSS Statistics for Windows, version 23.0). Statistical analyses were carried out using the Student's t test for independent and paired samples. A P value of < 0.05 was considered statistically significant and cumulative survival was calculated by the KaplanMeier method.RESULTS The mean follow-up was 87.6 ± 25.6 mo(range 3-120 mo). 25 cases(43.1%) were classified as minor defects, and 33 cases(56.9%) as major defects. The preoperative HHS rating improved significantly from a mean of 40.7 ± 6.1(range: 29-53) before revision, to a mean of 85.8 ± 6.1(range: 70-94) at the end of the follow-up(Student's t test for paired samples: P < 0.001). Considering HHS only at the end of follow-up, no statistically significant difference was observed between patients with a major or minor defect(Student's t test for independent samples: P > 0.05). Radiolucent lines were found in 4 implants(6.9%). Postoperative acetabular gaps were observed in 5 hips(8.6%). No signs of implant mobilization or areas of periprosthetic osteolysis were found in the x-rays at the final follow-up. Only 3 implants failed: 1 case of infection and 2 cases of instability. Defined as the end-point, cumulative survival at 10 years was 95%(for all reasons) and 100% for aseptic loosening of the acetabular component.CONCLUSION The medium-term use of prosthetic tantalum components in prosthetic hip revisions is safe and effective in a wide variety of acetabular bone defects.

Acetabular Reconstruction with Massive Allograft Shaped to the Cavity and Kerboull-Type Acetabular Reinforcement Device for Multiple Failures of Impaction Bone Graft: A Case Report

Acetabular component revision in the presence of severe bone loss is difficult for reconstructing an acetabular component in the anatomical hip center. Various treatment options are available, although often the acetabular defect cannot be corrected with a single option alone. Precise assessment of the bone loss and a suitable combination of methods are needed. Here we report a case of multiple failures with impaction bone grafting reconstruction for an acetabular bone defect of American Academy of Orthopedic Surgeons classification type III. We finally reconstructed the acetabulum with three femoral head allografts and a Kerboull-type acetabular reinforcement device. The allograft was a casted, jet-type helmet-like shape. A year later the patient was able to walk without a cane and perform light agricultural work. Accurate evaluation of the acetabular bone loss and appropriate reconstruction is important.

Femoroacetabular impingement is more common in military veterans with end-stage hip osteoarthritis than civilian patients: a retrospective case control study

Background: The purpose of this study was to compare the frequency of femoroacetabular impingement(FAI) between matched groups of military veterans and civilian patients with end-stage hip osteoarthritis(OA).Methods: Patients who underwent a primary total hip arthroplasty(THA) between January 1, 2015 and December 31, 2015 at a single Veteran’s Affairs Hospital were identified. Veterans were then matched 1:2 with civilian patients from our prospective outcome registry. The alpha angle and lateral center-edge angle(LCEA) were measured by a single evaluator. Independent t-tests were used to compare joint angles, and Fisher exact tests were used to compare the prevalence of cam(alpha angle ≥60°), pincer(LCEA ≥40°), or mixed-type pathologies.Results: Twenty-one veterans were matched 1:2 with civilian patients. The mean alpha angle did not significantly differ between groups(P=0.33) nor did the prevalence of cam deformities(P=0.79). The LCEAs were significantly greater in veterans than in civilians(P=0.04), and veterans also demonstrated a significantly greater prevalence of pincer and mixed-type deformities than civilians(P=0.025 and P=0.004, respectively).Conclusions: These results suggest that FAI is perhaps a more common mechanism in the progression of OA in a veteran population than in a civilian population, as pincer and mixed-type deformities were significantly more common among veterans than civilians. The forces borne by the hip during military training exceed normal physiologic conditions. In addition, the time between symptom onset and surgical correction may be 10–12 months longer for active military personnel than for civilians. The combination of increased physical demands and a protracted time to treatment highlights the need for better recognition of FAI in military members. Future studies are necessary to determine whether earlier intervention may prevent or delay the progression to end-stage OA and the need for total hip arthroplasty.

Interobserver and intraobserver agreement for Letournel acetabular fracture classification system using 3-dimensional printed solid models

BACKGROUND Acetabular fractures pose diagnostic and surgical challenges.They are classified using the Judet-Letournel system,which is based solely on X-ray.However,computed tomography(CT)imaging is now more widely utilized in diagnosing these injuries.The emergence of 3-dimensional(3-D)printing technology in varying orthopedic fields has provided surgeons a solid model that improves their spatial understanding of complex fractures and ability to plan preoperatively.AIM To evaluate the reliability of the Judet-Letournel classification system of acetabular fractures,when using either CT imaging or 3-D printed models.METHODS Seven patients with acetabular fractures underwent pelvic CT imaging,which was then used to create solid,3-D printed models.Eighteen orthopaedic trauma surgeons responded to questionnaires regarding fracture classification and preferred surgical approach.The same questionnaire was completed using only CT imaging,and two weeks later,using only 3-D printed models.The inter-and intra-observer agreement rates were then analyzed.RESULTS Inter-observer agreement rates based on CT imaging or 3-D printed models were moderate for fracture classification:κ=0.44,κ=0.55,respectively(P<0.001)and fair for preferred surgical approach:κ=0.34,κ=0.29,respectively(P<0.005).Intra-observer agreement rates for fracture classification and preferred surgical approach comparing CT imaging or 3-D printed models were moderate:κ=0.48,κ=0.41,respectively.No significant difference in intra-observer agreement was detected when comparing orthopedic pelvic specialists to general orthopedic traumatologists.CONCLUSION The Judet-Letournel classification demonstrated only moderate rates of agreement.The use of 3-D printed models increased the inter-observer agreement rates with respect to fracture classification,but decreased it with respect to the preferred surgical approach.This study highlights the role of 3-D printed models in acetabular fractures by improving spatial understanding of these complex injuries,thus providing more reliable fracture diagnoses and alternative viewpoints for pre-operative planning.

Morphology of Acetabulum and Femoral Head-Neck Junction in Hip Dysplasia Which Underwent Rotational Acetabular Osteotomy

The purpose of this study was to evaluate the preoperative radiographs with cases of developmental dysplasia of the hip (DDH) leading to rotational acetabular osteotomy (RAO) or curved peri-ace-tabular osteotomy (CPO), and examine the frequency of femoroacetabular impingement (FAI) related bone morphology in the acetabulum and femoral head-neck junction. Twenty-four hips with hip dyaplasia who underwent CPO or RAO were included in this study. Six hips had grade 0 and eighteen hips had grade 1 OA according to the T&ouml;nnis classification. We excluded patients with moderate and severe hip osteoarthritis and major femoral head deformities. Preoperative radiograph was evaluated on sharp angle, center-edge angle, alpha angle, crossover sign and posterior wall sign. Crossover signs were revealed in 7 hips (29.2%);posterior wall signs were revealed in 16 hips (66.7%);and cam-type deformities with an alpha angle of ≥50.5&deg;were observed in 19 hips (79.2%) in preoperative evaluation. As determined using the T&ouml;nnis scale, no progression of osteoarthritis was found in 16 of the 24 hips;there was a one-grade progression in 8 hips. Among the 8 hips, either positive cross-over sign or posterior sign in acetabulum, and an alpha angle of ≥50.5&deg;in femur were observed in six hips with progression of osteoarthritis. The presence of cam-type deformity and acetabular retroversion in patients who underwent RAO or CPO was relatively high in preoperative radiographs, and caution should be employed during surgery in patients with DDH. There is a possibility of secondary FAI due to excessive forward coverage of the bone fragments after RAO and CPO.

Anatomic Anteversion of the Acetabular Component Correlates with Polyethylene Linear Wear in Total Hip Arthroplasty: The Three-Dimensional Numerical Analysis

Background: Although abduction of the acetabular component is considered to predict factors for polyethylene wear attributable to osteolysis, other radiographic factors have yet to be elucidated. The purpose of the present study was to evaluate whether anteversion or change in implantation angle of the acetabular component influences polyethylene linear wear by using standing and supine radiographs of the hip joint. Methods: Standing and supine plain anteroposterior radiographs of 62 hip joints in which cementless total hip arthroplasty was performed were examined for polyethylene linear wear rate (mm/year), pelvic inclination, and radiological inclination and anatomic anteversion of the acetabular component. Results: All correlation coefficients of measurements of polyethylene linear wear, pelvic inclination angle, anatomical anteversion angle and radiological inclination angle were calculated highly. And by the three-dimensional numerical analysis, anatomic anteversion of the acetabular component had at least some effect on the degree of polyethylene wear. Conclusion: This study suggests that increased anteversion of the acetabular component reduces polyethylene linear wear in metal-on-polyethylene total hiparthroplasty.

Acetabular cup version modelling and its clinical applying on plain radiograms

AIM To measure the sensitivity and specificity of the cup version assessment by using only anteroposterior hip and pelvis views, evaluate the incidence of inadequate cup version in patients with repeated dislocations after total hip arthroplasty(THA). METHODS Radiographic retrospective analysis of 2 groups of patients, with follow up of 6-60 mo, after undergoing primary THA. First group of 32 patients(20 female, 12 male) with unilateral THA(32 hips) required early revision arthroplasty for reasons of dislocation. The mean age and mode were 59(from 38 to 83) and 66 ages respectively. The average body mass index(BMI) was 24.2(from 17.7 to 36.3), mode 23.9. Second group was consisted of 164 patients(101 female, 63 male) without dislocations during the follow-up period(170 hips). Among them 6 patients required bilateral THA. The mean age was 60(from 38 to 84) and mode 59. BMI was 24.8(17.2-36.8), mode 25.2. Clinical significance of the cup anteversion sign was estimated with cross tabulation 2 × 2. RESULTS The value of the χ~2 yates was 10.668(P < 0.01).Sensitivity of SAI(sign of anteversion insufficiency) was 29%(95%CI: 9%-46%), and specificity was 92%(95%CI: 88%-96%). Relative risk of dislocation in patients with SAI was 3.4(95%CI: 1.8-6.3). CONCLUSION This method provides the surgeons with the ability to perform a reliable and simple qualitative assessment of the acetabular component version. It can be useful during patient examination with early loosening of the implant, dislocations, and impingement. Additionally, it can provide necessary information during planning of revision surgery, especially when considering question about cup replacement, although final assessment of the cup position should be done with a computed tomography scan.

ACETABULAR ROTATION OSTEOTOMY IN THE TREATMENT OF ACETABULAR DYSPLASIA IN ADULTS

Acetabular dysplasia is one of the most important reasons for development ofsecondary osteoarthrosis of the hip joint. This paper introduced a method of modifiedWagner’s procedure, called acetabular rotation osteotomy for the treatment of severeacetabular dysplasia in ten adults patients. These were followed up for 1-4 years. Fivecriteria including pain, gait, range of motion, measurement of roentgenographic changees,and CT scan were evaluated. From the limited information of this paper, it showed thatin all cases pain improved and range of motion did not reduced significantly. Comparingthe pre- and post-operative x-ray films, CE angle increased and exceeded the normal val-ue. Tonnis hip value decreased and approached the normal value, anteversion of theacetabulum improved, and the percentage of acetabular coverage increased as well.

Optimum Combination of Femoral Head Size, Femoral Head Material, and Acetabular Cup Liner’s Highly-Cross-Linked Polyethylene Brand for Hip Implant

Clinical two-dimensional linear wear rate data for acetabular cup liners fabricated using approved brands of highly cross-linked ultra-high-molecular-weight polyethylene, as reported in 39 articles in the literature, were analyzed using a statistical technique called response surface methodology. The output was a series comprising16 acceptable combinations of femoral head diameter (HD), femoral head material (HM), and HXLPE brand (PB), each of which would yield the optimum wear rate (herein taken to be a wear rate of practically zero). An example of such a combination is 28- mm-diameter Oxinium? femoral head articulated against an acetabular cup liner fabricated from ReflectionTM HXLPE. The findings in this work may guide an orthopaedic surgeon’s selection of the combination of HD, HM, and PB to use in a primary total hip joint replacement.