Total Hip Resurfacing Research Articles

A comparison of postoperative microbiological and histological test results with the indication for revision as listed at the time of surgery in the National Joint Registry: a single-centre cohort study of metal-on-metal total hip replacement and hip resurfacing revision procedures.

Surgeons allocate an indication(s) for revision surgery on NJR Minimum Data Set forms in the immediate perioperative period, when results from intraoperative histology and microbiology samples are not available. We evaluated to what extent the postoperative diagnostics obtained for patients undergoing metal-on-metal hip arthroplasty (MoMHA) revision surgery align with the indication for revision listed in the NJR. NJR data for MoMHA revision patients (2004-2015) at a single centre were linked to hospital records of microbiology and histology testing for prosthetic joint infection (PJI) and adverse reaction to metal debris (ARMD). The Musculoskeletal Infection Society and Mirra classifications were used as "gold standards' to classify PJI and ARMD respectively and to assess the diagnostic accuracy of the clinician selected revision indication recorded on MDS forms. Of 301 cases, 5.6% (n = 17) and 3.7% (n = 11) were revised for PJI and ARMD respectively. In a further 6.6% (n = 20, PJI) and 15.6% (n = 47, ARMD) the indication for revision selected at the time of surgery did not corroborate with the test results from intraoperative samples. Diagnostic accuracy analysis revealed sensitivity and specificity of indication for surgery at the time of revision for PJI of 35.5% (95% CI, 19.2-54.6) and 97.8% (CI, 54.6-95.2) respectively, and for ARMD of 7.41% (CI, 2.06-17.9) and 97.2% (CI, 94.3-98.9) respectively. We observed that the results of histology and microbiology analyses of intraoperative samples may provide evidence to support alternative diagnoses in 20% of cases. This indicates a need for a change in the work-up of these cases to allow a more accurate prediction of the indication for revision. Alternatively, if there was evidence of a difference in outcome for patients where the indication may be changed when such data becomes available, the feasibility of a facility to add additional information from samples taken intraoperatively when it becomes available should be explored.

Return to surfing following hip arthroplasty.

To date, no previous studies have explored return to surfing after hip arthroplasty. The objective of this study is to analyse return to a risky activity following hip arthroplasty. A retrospective chart review was conducted on all primary total hip arthroplasties (THA) and hip resurfacing arthroplasties (HRA) performed by the senior author from 2014 to 2021. Patients identified as surfers were contacted to complete a survey including surfing history and patient-reported outcomes. 83 hips in 67 patients were contacted. There were 66 THAs and 17 HRAs. 81 hips were performed through a posterior approach and 2 through an anterior approach. At an average of 67 months, there were no dislocations and no patients reported hip pain while surfing. Time to resume surfing was a median of 16 (range 8-144) weeks. Among 13 patients who did not return to surfing, 8 cited new lifestyle restrictions, 4 attributed it to other arthritic joints, and only 1 patient attributed their limitation to the replaced hip. This group had taken significantly more time off from surfing prior to surgery. Return to surfing following THA and HRA is common and safe in our study population with no complications and specifically no dislocations. Patients with other sites of arthritis and patients who have more extensive time away from surfing prior to surgery are less likely to return to sport. While surfing is clearly not without risk, patients can generally expect a high rate of successful return to surfing after hip arthroplasty.

Clinical outcomes and return to dance after total hip arthroplasty or hip resurfacing in professional dancers.

Professional dancers represent a unique patient population in the setting of hip arthroplasty, given the high degree of hip strength and mobility required by their profession. We sought to determine the clinical outcomes and ability to return to professional dance after total hip arthroplasty (THA) or hip resurfacing arthroplasty (HRA). Active professional dancers who underwent primary THA or HRA at a single institution with minimum one-year follow-up were included in the study. Primary outcomes included the rate of return to professional dance, three patient-reported outcome measures (PROMs) (modified Harris Hip Score (mHHS), Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS-JR), and Lower Extremity Activity Scale (LEAS)), and postoperative complications. A total of 49 hips in 39 patients (mean age 56 years (SD 13); 80% female (n = 39)) were included. Mean follow-up was 4.9 years (SD 5.1). Of these 49 hips, 37 THAs and 12 HRAs were performed. In all, 96% of hips returned to professional dance activities postoperatively. With regard to PROMs, there were statistically significant improvements in mHHS, HOOS-JR, and LEAS from baseline to ≥ one year postoperatively. There were complications in 7/49 hips postoperatively (14%), five of which required revision surgery (10%). There were no revisions for instability after the index procedure. Two complications (5.4%) occurred in hips that underwent THA compared with five (42%) after HRA (p = 0.007), though the difference by procedure was not significantly different when including only contemporary implant designs (p = 0.334). Active professional dancers experienced significant improvements in functional outcome scores after THA or HRA, with a 96% rate of return to professional dance. However, the revision rate at short- to mid-term follow-up highlights the challenges of performing hip arthroplasty in this demanding patient population. Further investigation is required to determine the results of THA versus HRA using contemporary implant designs in these patients.

Assessing brain integrity in patients with long-term and well-functioning metal-based hip implants.

Production of metal debris from implant wear and corrosion processes is now a well understood occurrence following hip arthroplasty. Evidence has shown that metal ions can enter the bloodstream and travel to distant organs including the brain, and in extreme cases, can induce sensorial and neurological diseases. Our objective was tosimultaneously analyze brain anatomy and physiology in patients with long-term and well-functioning implants. Included were subjects who had received total hip or hip resurfacing arthroplastywith an implantation time of a minimum of 7 years (n = 28) and age- and sex-matched controls (n = 32). Blood samples were obtained to measure ion concentrations of cobalt and chromium, and the Montreal Cognitive Assessment was performed. 3T MRI brain scans were completed with an MPRAGE sequence for ROI segmentation and multiecho gradient echo sequences to generate QSM and R2* maps. Mean QSM and R2* values were recorded for five deep brain and four middle and cortical brain structures on both hemispheres: pallidum, putamen, caudate, amygdala, hippocampus, anterior cingulate, inferior temporal, and cerebellum. No differences in QSM or R2* or cognition scores were found between both groups (p > 0.6654). No correlation was found between susceptibility and blood ion levels for cobalt or chromium in any region of the brain. No correlation was found between blood ion levels and cognition scores.Clinical significance: Results suggest that metal ions released by long-term and well-functioning implants do not affect brain integrity.

Comprehensive Review on Biomaterials and Their Inherent Behaviors for Hip Repair Applications.

Developing biomaterials for hip prostheses is challenging and requires dedicated attention from researchers. Hip replacement is an inevitable and remarkable orthopedic therapy for enhancing the quality of patient life for those who have arthritis as well as trauma. Generally, five types of hip replacement procedures are successfully performed in the current medical market: total hip replacements, hip resurfacing, hemiarthroplasty, bipolar, and dual mobility systems. The average life span of artificial hip joints is about 15 years, and several studies have been conducted over the last 60 years to improve the performance and thereby increase the lifespan of artificial hip joints. Present-day prosthetic hip joints are linked to the wide availability of biomaterials. Metals, ceramics, and polymers are some of the most promising types of biomaterials; nevertheless, each biomaterial has advantages and disadvantages. Metals and ceramics fail in most applications owing to stress shielding and the emission of wear debris; ongoing research is being carried out to find a remedy to these unfavorable responses. Recent research found that polymers and composites based on polymers are significant alternative materials for artificial joints. With growing research and several biomaterials, recent reviews lag in effectively addressing hip implant materials' individual mechanical, tribological, and physiological behaviors. This Review comprehensively investigates the historical evolution of artificial hip replacement procedures and related biomaterials' mechanical, tribological, and biological characteristics. In addition, the most recent advances are also discussed to stimulate and guide future researchers as they seek more effective methods and synthesis of innovative biomaterials for hip arthroplasty application.

Outcome of hip resurfacing revision through the Hueter-anterior approach.

The Hueter-Anterior Approach (HAA) with its limited soft tissue and internervous dissection has been shown to be an effective approach for primary total hip and hip resurfacing arthroplasty (HRA). The purpose of this study is to evaluate the clinical outcome of patients requiring revision of HRA to total hip replacement using the HAA, assessing function and complications. We performed a retrospective review of a prospectively maintained research database. Between 2006 and 2015, 555 primary metal-on-metal (MoM) HRAs were performed via the HAA; we identified 33 hips in 30 patients that required revisions for aseptic causes to THA: aseptic loosening of acetabulum in 12 and femoral in 7, 10 for pseudotumour/ALTR, 4 for femoral neck fracture. All revision surgeries were performed through a HAA by a single surgeon who had also performed the index operation. PROMs were collected preoperatively and yearly at various timepoints postoperatively. The mean age at time of revision was 48.9 years (±5.3 SD) for 22 males (67%) and 11 females (33%). The mean time to revision surgery/failure of hip resurfacing was 3.3 years (±2.4 SD). There were 5 major reoperations with 3 infections, 1 acetabular loosening and 1 trunnionosis. There were significant improvements in multiple PROMs. The HAA is a viable surgical approach for revision of HRA with smaller initial HRA acetabular components generally requiring a relatively larger acetabular compoent at time of revision. Patients reported improvement in symptoms and function and a lower risk of subsequent reoperation than what has previously been reported for failed MoM bearings.

CLINICAL OUTCOMES AND RETURN TO DANCE AFTER TOTAL HIP ARTHROPLASTY OR HIP RESURFACING IN COMPETITIVE (PROFESSIONAL) DANCERS

Competitive dancers represent a unique patient population in the setting of hip arthroplasty given the high degree of hip strength and mobility required by their profession. We sought to determine the clinical outcomes and ability to return to competitive dance after total hip arthroplasty (THA) or hip resurfacing arthroplasty (HRA) among competitive dancers.Active competitive dancers who underwent primary THA or HRA at a single institution with minimum one-year follow-up were included in the study. Primary outcomes included (1) the rate of return to competitive dance, (2) three PROMs (modified Harris Hip Score [mHHS], Hip Disability and Osteoarthritis Outcome Score for Joint Replacement [HOOS-JR], and Lower Extremity Activity Scale [LEAS]), and (3) post-operative complications.Forty-nine hips in 39 patients (mean age 56±13 years; 80% female) were included. Mean follow-up was 4.9±5.1 years. Thirty-seven THAs and 12 HRAs were performed. Ninety-six percent of patients returned to competitive dance activities post-operatively. With respect to PROMs, there were statistically significant improvements in mHHS, HOOS-JR, and LEAS from baseline to ≥ 1 year post-operatively. There were complications in 9/49 (18%) hips post-operatively, five (10%) of which required revision surgery.Active competitive dancers experienced significant improvements in functional outcome scores after THA or HRA, with a rate of return to competitive dance of 96%.

Comparisons of in-hospital complications between total hip arthroplasty and hip resurfacing arthroplasty

BackgroundHip resurfacing arthroplasty (HRA) is a less common but effective alternative method to total hip arthroplasty (THA) for hip reconstruction. In this study, we investigated the incidences of in-hospital complications between patients who had been subjected to THA and HRA.MethodsThe National Inpatient Sample data that had been recorded from 2005 to 2014 was used in this study. Based on the International Classification of Disease, Ninth Revision, Clinical Modification, patients who underwent THA or HRA were included. Data on demographics, preoperative comorbidities, length of hospital stay, total charges, and in-hospital mortality and complications were compared. Multiple logistic regression analysis was used to determine whether different surgical options are independent risk factors for postoperative complications.ResultsA total of 537,506 THAs and 9,744 HRAs were obtained from the NIS database. Patients who had been subjected to HRA exhibited less preoperative comorbidity rates, shorter length of stay and extra hospital charges. Moreover, HRA was associated with more in-hospital prosthesis loosening. Notably, patients who underwent HRA were younger and presented less preoperative comorbidities but did not show lower incidences in most complications.ConclusionsThe popularity of HRA gradually reduced from the year 2005 to 2014. Patients who underwent HRA were more likely to be younger, male, have less comorbidities and spend more money on medical costs. The risk of in-hospital prosthesis loosening after HRA was higher. The HRA-associated advantages with regards to most in-hospital complications were not markedly different from those of THA. In-hospital complications of HRA deserve more attention from surgeons.

Running Following Hip Arthroplasty: A Systematic Review

With improved implants and younger patients undergoing total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA), there are increased expectations to return to high-impact activities. Recommendations regarding return to running following hip arthroplasty remain unclear. A search of the PubMed database was conducted, and all publications referencing running following THA or HRA published between January 1, 2000, and September 1, 2020, were included in the systematic review. Patient demographics, surgical variables, activity measures, and revision rates were recorded for each study. A total of 225 unique citations were identified, of which four manuscripts met the eligibility criteria. Eighty-nine of 121 (73.6%) preoperative runners returned to running postoperatively. All four studies reported mean postoperative UCLA activity scores of at least nine. More patients returned to running following HRA than THA with lower rates of revision. Further research with longer postoperative follow-up is necessary to provide definitive recommendations for running following arthroplasty procedures. (Journal of Surgical Orthopaedic Advances 32(1):001-004, 2023).

A Comparison of Hip Muscle Mass, Muscle Power, and Clinical Outcomes with Long-Term Follow-Up in Patients with Metal-on-Metal Hip Arthroplasty Compared to Metal-on-Polyethylene Hip Arthroplasty

(1) Background: Metal-on-metal (MoM) total hip arthroplasty (THA) and hip resurfacing arthroplasty (HRA) was presumed to provide superior functional outcomes compared to metal-on-polyethylene (MoP) THA. (2) Methods: We compared muscle mass, power, step test asymmetry, and patient-reported outcomes between MoM THA/HRA and MoP THA. A total of 51 MoM THA/HRAs and 23 MoP THAs participated in the cross-sectional study at a mean of 6.5 (2.4–12.5) years postoperatively. Muscle mass was measured by Dual energy X-ray Absorption (DXA) scans and muscle power in a Leg Extensor Power Rig. Step test asymmetry was obtained with an Inertial Measurement Unit (IMU). The patients completed the Harris Hip Score (HHS) and the Copenhagen Hip and Groin Outcome Score (HAGOS). (3) Results: The MoM THA/HRA group had a greater inter-limb difference in hip muscle mass compared to the MoP THA group (p = 0.02). Other inter-limb differences in muscle mass and power were similar (p > 0.05). Muscle mass of the thigh and calf area and muscle power in both legs were higher in MoM THA/HRA compared to MoP THA (p < 0.009). Step test time asymmetry when ascending was lower in MoM THA/HRA compared to MoP THA (p = 0.03). HHS and HAGOS scores were similar between groups (p > 0.05). (4) Conclusion: Overall, we could not verify the hypothesis that MoM THA/HRA contributes to superior functional outcomes compared to MoP THA.

Debridement, antibiotics and implant retention for prosthetic joint infection: comparison of outcomes between total hip arthroplasty and hip resurfacing.

The management of prosthetic joint infection (PJI) has been widely studied in the context of total hip arthroplasty (THA). However, the outcomes of debridement, antibiotics and implant retention (DAIR) for PJI have never been compared between hip resurfacing arthroplasty (HRA) and THA. This led us to carry out a retrospective case-control study comparing the surgical treatment of post-operative infections between HRA and THA to determine the infection remission rate and the medium-term functional outcomes. This single-centre case-control study analysed 3056 HRA cases of which 13 patients had a PJI treated by DAIR. These patients were age-matched with 15 infected THA hips treated by DAIR and modular component exchange (controls). Their survival (no recurrence of the infection) was compared and factors that could affect the success of the DAIR were explored: sex, body mass index, age at surgery, presence of haematoma, type of bacteria present and antibiotic therapy. At a mean follow-up of fiveyears (2-7), the infection control rate was significantly higher in the HRA group (100% [13/13]) than in the THA group (67% [10/15]) (p = 0.044). More patients in the THA group had undergone early DAIR (< 30days) (73% [11/15]) than in the HRA group (54% [7/13]). There was no significant difference between the two groups in the ASA score, presence of comorbidities, body mass index and duration of the initial arthroplasty procedure. At the review, the Oxford-12 score of 17/60 (12-28) was better in the HRA group than the score of 25/60 (12-40) in the THA group (p = 0.004). DAIR, no matter the time frame, is a viable therapeutic option for infection control after HRA.

Harris Hip Score and SF-36 following metal-on-metal total hip arthroplasty and hip resurfacing - a randomized controlled trial with 5-years follow up including 75 patients

BackgroundThe metal-on-metal large-diameter-head (MoM-LDH) hip replacements increased in popularity during the start of the twenty-first century. Subsequently reports raised concerns regarding adverse reactions due to elevated chromium (Cr) and cobalt (Co) concentrations as well as high rates of other complications and revisions.The purpose was to compare Harris Hip Score and SF-36 at 5-years follow up following MoM-LDH total hip arthroplasty (MoM-LDH-THA) or MoM hip resurfacing (MoM-HR).MethodsThe study was conducted between November 2006 to January 2012 in a tertiary health care center in Denmark. Patients with primary or secondary osteoarthritis were randomly assigned to receive a Magnum (MoM-LDH-THA) or a Recap (MoM-HR) prosthesis. Randomization was computer generated and allocation was concealed in an opaque envelope. Neither patients nor care provider were blinded. Primary outcome was Harris Hip Score at 5-years follow up.ResultsSeventy-five were included and allocated to the MoM-LDH-THA (n = 39) and MoM-HR (n = 36) group. The study was prematurely stopped due to numerous reports of adverse events in patients with MoM hip replacements. Thirty-three in the MoM-LDH-THA and 25 in the MoM-HR group were available for primary outcome analysis.Median Harris Hip Score was 100 (IQR: 98–100) for MoM-LDH-THA and 100 (IQR: 93–100) for MoM-HR (p = 0.486). SF-36 score was high in both groups with no significant difference between groups.ConclusionHarris Hip Score and SF-36 score was excellent in both groups with no significant difference at 5-years follow up. Our findings suggest that there is no clinical important difference between the two prostheses implanted 5 years after implantation.Trial registrationClinicalTrials.gov, NCT04585022, Registered 23 September 2020 – Retrospectively registered.This study was not prospectively registered in a clinical trial database since it was not an entirely implemented standard procedure in the international orthopedic society when the study was planned.

Despite higher revision rate, MoM large-head THA offers better clinical scores than HR: 14-year results from a randomized controlled trial involving 48 patients

BackgroundThe high failure rates of metal on metal (MoM) large diameter head total hip arthroplasty (LDH THA) and hip resurfacing (HR) prevented their long-term comparisons with regards to clinical outcome. Such knowledge would be important as ceramic LDH bearing is now available. With long-term follow-up, we investigated the difference in 1) patient-reported outcome measures (PROMs); 2) revision and adverse events rates, and 3) metal ion levels between MoM LDH THA and HR.MethodsForty-eight patients were randomized for LDH THA (24) or HR (24) with the same MoM articulation. At a mean follow-up of 14 years, we compared between groups different PROMs, the number of revisions and adverse events, whole blood Cobalt (Co) and Chromium (Cr) ion levels, and radiographic signs of implant dysfunction.ResultsLDH THA (all cases: revised and well-functioning) had significantly better WOMAC (94 versus 85, p = 0.04), and more frequently reported having no limitation (p = 0.04). LDH THA revision rate was 20.8% (5/24) versus 8.3% (2/24) for HR (p = 0.4). Mean Co and Cr ion levels were higher in LDH THA compared to the HR (Co: 3.8 μg/L vs 1.7 μg/L; p = 0.04 and Cr: 1.9 μg/L vs 1.4 μg/L, p = 0.1). On radiographic analyses, 2 LDH THAs showed signs of adverse reaction to metal debris, whereas 1 loose femoral HR component was documented.ConclusionIn the long-term, MoM LDH THA had a high trunnion related revision rate but nonetheless showed better PROMs compared to HR. Provided with a well-functioning modular junction, non-MoM LDH THA would offer an appealing option.Trial registrationClinicalTrials.gov (NCT04516239), August 18, 2020. Retrospectively registered.

Clinical Feasibility of Multi-Acquisition Variable-Resonance Image Combination-Based T2 Mapping near Hip Arthroplasty.

Background: Hip arthroplasty is increasingly prevalent, and early detection of complications can improve outcomes. Quantitative magnetic resonance imaging (qMRI) methods using multi-acquisition variable-resonance image combination (MAVRIC) may allow for the assessment of soft tissues in close proximity to hip arthroplasty devices. Question/Purposes: We sought to determine the clinical feasibility of MAVRIC-based T2 mapping as a qMRI approach for assessing synovial reactions in patients with a hip arthroplasty device. We hypothesized that there would be differences in T2 metrics by synovial type, clinical impression, and clinical findings related to synovitis. Methods: We conducted a cross-sectional study of 141 subjects with 171 hip arthroplasties with greater than 1 year post-implantation. We enrolled subjects who had had a primary total hip arthroplasty or hip resurfacing arthroplasty between May 2019 and March 2020, excluding those with a revision hip arthroplasty and those with standard safety contraindications for receiving an MRI. Institutional standard 2D fast spin echo (FSE), short-tau inversion recovery (STIR), and susceptibility-reduced MAVRIC morphological MR images were acquired for each hip and followed by a dual-echo acquisition MAVRIC T2 mapping sequence. Results: While 131 subjects (81%) were classified as having a "normal" synovial reaction, significantly longer T2 values were found for fluid synovial reactions compared with mixed reactions. In addition, subjects with synovial dehiscence and decompression present had T2 prolongation. Larger synovial volumes were found in subjects with low-signal intensity deposits. Conclusions: MAVRIC-based T2 mapping is clinically feasible and there are significant quantitative differences based on type of synovial reaction. Patients undergoing hip arthroscopy revision surgery will warrant comparison of T2 values with direct histologic assessment of a tissue sample obtained intraoperatively. The approach used in this study may be used for a quantitative evaluation and monitoring of soft tissues around metal implants.

Dual Mobility Total Hip Arthroplasty is not Associated with a Greater Incidence of Groin Pain in Comparison with Conventional Total Hip Arthroplasty and Hip Resurfacing: A Retrospective Comparative Study

Groin pain is a common long-term complication of total hip arthroplasty (THA). Femoral head size has been proposed as one of the primary causes. The implants used in dual mobility (DM) THA have large outer-bearing articulations, which could increase the risk of post-operative groin pain. Hip resurfacing (HR), too, has been shown to be associated with a risk of groin pain. The goals of this study were to compare the incidence of groin pain at 1year after hip arthroplasty in patients with different femoral head diameters and in patients undergoing conventional THA, DM THA, and HR. After combing an institutional registry for all patients who had undergone THA or HR for primary hip osteoarthritis, we included 3193 patients in the analysis; 2008 underwent conventional THA, 416 underwent DM THA, and 769 underwent HR. We used logistic regression modeling to analyze the relation of groin pain at 1year after surgery to patient demographics and clinical characteristics, including age, sex, body mass index (BMI), University of California at Los Angeles activity score at 1year after surgery, bearing couple, and the ratio of acetabular diameter to femoral head diameter. We also measured cup inclination and anteversion in a subset of patients with and without groin pain at 1year to assess whether pain could be related to implant position. Overall, 8.7% of patients reported groin pain at 1year. Patients with groin pain were younger and had lower BMIs. There were increased odds of groin pain with a greater cup-to-head ratio, although DM implants, interestingly, were not significantly associated with groin pain; this may be attributable to so much of their movement taking place inside the implant. Subgroup analysis measuring cup inclination and anteversion showed no difference in cup position between patients with and without pain. In this population of hip arthroplasty patients, the incidence of groin pain 1year after surgery did not differ among patients undergoing DM and conventional THA; DM THA in particular was not associated with a higher risk of groin pain, despite its comparatively larger femoral head sizes. HR, on the other hand, was associated with a higher risk of pain. Appropriate implant sizing and bearing couple choice may optimize the functional benefit of THA.

Artificial Intelligence to Identify Arthroplasty Implants From Radiographs of the Hip

BackgroundThe surgical management of complications surrounding patients who have undergone hip arthroplasty necessitates accurate identification of the femoral implant manufacturer and model. Failure to do so risks delays in care, increased morbidity, and further economic burden. Because few arthroplasty experts can confidently classify implants using plain radiographs, automated image processing using deep learning for implant identification may offer an opportunity to improve the value of care rendered. MethodsWe trained, validated, and externally tested a deep-learning system to classify total hip arthroplasty and hip resurfacing arthroplasty femoral implants as one of 18 different manufacturer models from 1972 retrospectively collected anterior-posterior (AP) plain radiographs from 4 sites in one quaternary referral health system. From these radiographs, 1559 were used for training, 207 for validation, and 206 for external testing. Performance was evaluated by calculating the area under the receiver-operating characteristic curve, sensitivity, specificity, and accuracy, as compared with a reference standard of implant model from operative reports with implant serial numbers. ResultsThe training and validation data sets from 1715 patients and 1766 AP radiographs included 18 different femoral components across four leading implant manufacturers and 10 fellowship-trained arthroplasty surgeons. After 1000 training epochs by the deep-learning system, the system discriminated 18 implant models with an area under the receiver-operating characteristic curve of 0.999, accuracy of 99.6%, sensitivity of 94.3%, and specificity of 99.8% in the external-testing data set of 206 AP radiographs. ConclusionsA deep-learning system using AP plain radiographs accurately differentiated among 18 hip arthroplasty models from four industry leading manufacturers.

The burden and utility of routine follow-up at one year after primary arthroplasty.

Routine surveillance of primary hip and knee arthroplasties has traditionally been performed with office follow-up visits at one year postoperatively. The value of these visits is unclear. The present study aims to determine the utility and burden of routine clinical follow-up at one year after primary arthroplasty to patients and providers. All patients (473) who underwent primary total hip (280), hip resurfacing (eight), total knee (179), and unicompartmental knee arthroplasty (six) over a nine-month period at a single institution were identified from an institutional registry. Patients were prompted to attend their routine one-year postoperative visit by a single telephone reminder. Patients and surgeons were given questionnaires at the one-year postoperative visit, defined as a clinical encounter occurring at nine to 15 months from the date of surgery, regarding value of the visit. Compliance with routine follow-up at one year was 35%. The response rate was over 80% for all questions in the patient and clinician surveys. Overall, 75% of the visits were for routine surveillance. Patients reported high satisfaction with their visits despite the general time for attendance, including travel, being over four hours. Surgeons found the visits more worthwhile when issues were identified or problems were addressed. Patient compliance with follow-up at one year postoperatively after primary hip and knee is low. Routine visits of asymptomatic patients deliver little practical value and represent a large time and cost burden for patients and surgeons. Remote strategies should be considered for routine postoperative surveillance primary hip and knee arthroplasties beyond the acute postoperative period. Cite this article: Bone Joint J 2020;102-B(7 Supple B):85-89.

Design of custom-made navigational template of femoral head and pilot research in total hip resurfacing arthroplasty

BackgroundTo develop a novel custom-made navigational template for accurate prosthesis implantation in total hip resurfacing arthroplasty (THRA) by computer-aided technology.MethodsThe template was produced based on data preoperatively acquired from computed tomography (CT) scan. The position of the drill guide was obtained according to the anatomical axis of the femoral neck which was defined by the point of the femoral head center and another point of the femoral neck center. The final direction of the drill guide was confirmed by a valgus angle. The surface of the template was constructed based on the inverse of the femoral neck surface. Then the template was made of acrylate resin by using rapid prototyping (RP) technique. Finally, all the templates were verified in 17 cadavers arranged for THRA and postoperative medical images were employed to evaluate the accuracy and validity of the template.ResultsThe templates had achieved a high fitting with the femoral neck surface, and there were no guide failures. Postoperative evaluation revealed that the Kirschner-wires pass through the center of the femoral head and femoral neck, presenting a relative expected and acceptable valgus angle to the central axis of the femoral neck. The lateral offset showed the relative valgus angle achieved as expected, the horizontal offset showed that no obvious antero-posterior deviation occured. The comparison between the preoperative Neck-shaft angle (NSA) and the postoperative Stem-shaft angle (SSA) showed there is no significant difference(P > 0.05).ConclusionThe novel custom-made navigational template of femoral head can effectively assist surgeons for accurately implanting the femoral head components to the desired position in THRA.

Perioperative changes in pelvic tilt after hip resurfacing using a direct lateral approach

Background: Proper positioning of the acetabular component is critical for prevention of dislocation and excessive wear for total hip arthroplasty (THA) and hip resurfacing. Consideration of preoperative pelvic tilt (PT) may aid in acetabular component placement. The purpose of this study was to investigate how PT changes after hip resurfacing, via pre and post-operative radiographic analysis of anterior pelvic plane (APP), and whether radiographic analysis of the APP is a reproducible method for evaluating PT in resurfaced hips. Methods: A consecutive group of 228 patients from a single surgeon who had hip resurfacing were evaluated. We obtained X-rays from an institutional database for these patients who had their surgeries between January 1 st , 2014 to December 31 st , 2016. PT was measured by two observers before and after resurfacing utilizing a standardized radiographic technique. Correlation coefficients were calculated for PT measurements between observers, and pre- and post-surgery. Results: Mean preoperative PT was 0.7° (SD ±6.6°) and 0.4° (SD ±6.1°). Mean post-operative PT was −1.2° (SD ±6.2°) and −1.2° (SD ±6.0°). Correlations between pre and post-operative PT were R=0.829 (P 10°. Intraclass correlation coefficients between observers were R=0.987 (95% CI, 0.963–0.981; P Conclusions: After hip resurfacing arthroplasty (HRA), the mean difference between preoperative and postoperative PT was less than 1°. These results suggest that near-native PT is maintained with consistency after hip resurfacing, a finding that is variable following THA. Since variations in PT affect functional acetabular position, these results support the use of PT measurement in pre-operative planning for hip arthroplasty with a high degree of inter-observer reliability.

Wear Failure Analysis of UHMWPE Acetabular Cups in THR

The UHMWPE acetabular cups are the most popular joints for joint prostheses after Charnley introduced UHMWPE for the acetabular component in 1962. It has been demonstrated that polyethylene wear remains the main source of particles in the THR and therefore requires particular attention. The paper presents a series of theoretical and practical aspects regarding the wear of acetabular cups (made of UHMWPE) from the total hip prosthesis component. At the same time, the other tribological phenomena that occur in these MoP (metal on polyethylene) combinations are treated, such as lubrication and friction. Total Hip Replacement &amp; Hip Resurfacing A hip replacement involves replacing the hip joint with a mechanical bearing system which is comprised of a femoral component and an acetabular component. During a hip replacement the acetabulum is reamed and the acetabular component is fitted into the cavity and the femoral component can either be placed over a reamed femoral head, in a procedure referred to as hip resurfacing, or positioned inside the femoral shaft during a total hip replacement [1]. Fig. 1. Total Hip Replacement (a) and Hip Resurfacing Replacement (b) [2].