Examining the "revisability" benefit of hip resurfacing arthroplasty.

BACKGROUND: Hip resurfacing arthroplasty (HRA) is an alternative to total hip arthroplasty (THA) that is typically reserved for young active patients because it preserves bone. However, the benefits of HRA only hold true if conversion THA after failed HRA provides acceptable outcomes. AIM: To compare patient reported outcomes for conversion THA after HRA failure to primary THA. METHODS: A retrospective review of 36 patients (37 hips) that underwent conversion THA for failed HRA between October 2006 and May 2019 by a single surgeon was performed. Patient reported outcomes [modified Harris Hip Score (mHHS), University of California Los Angeles (UCLA) activity score] were obtained via an email-based responder-anonymous survey. Outcomes were compared to normative data of a primary THA cohort with similar demographics. Subgroup analysis was performed comparing outcomes of conversion THA for adverse local tissue reaction (ALTR) vs all other causes for failure. RESULTS: The study group had a lower mHHS than the control group (81.7 ± 13.8 vs 90.2 ± 11.6, P < 0.01); however, both groups had similar UCLA activity levels (7.5 ± 2.3 vs 7.2 ± 1.6, P = 0.51). Patients that underwent conversion for non-ATLR causes had similar mHHS (85.2 ± 11.5 vs 90.2 ± 11.6, P = 0.11) and higher UCLA activity levels (8.5 ± 1.8 vs 7.2 ± 1.6, P < 0.01) compared to the control group. Patients that underwent conversion for ATLR had worse mHHS (77.1 ± 14.5 vs 90.2 ± 11.6, P < 0.01) and UCLA activity levels (6.1 ± 2.3 vs 7.2 ± 1.6, P = 0.05) when compared to the control group. CONCLUSION: Patient outcomes equivalent to primary THA can be achieved following HRA conversion to THA. However, inferior outcomes were demonstrated for ALTR-related HRA failure. Patient selection and perhaps further studies examining alternative HRA bearing surfaces should be considered.

Establishing minimal clinically important differences and patient acceptable symptom state thresholds following birmingham hip resurfacing.

INTRODUCTION: Birmingham Hip Resurfacing (BHR) has emerged as a compelling and innovative alternative to total hip arthroplasty (THA), especially among young, active patients. However, the Minimal Clinically Important Difference (MCID) and the Patient Acceptable Symptom State (PASS) thresholds have not yet been determined for patients undergoing BHR. Therefore, the current study aimed to (1) determine the MCID and PASS thresholds for both the Hip disability and Osteoarthritis Outcome Score (HOOS)-Pain and HOOS physical function shortform (PS), for patients who underwent BHR; and (2) identify factors influencing the achievement of MCID and PASS for HOOS-Pain and HOOS-PS. METHODS: Prospectively collected data from patients undergoing BHR was analyzed. Patients with osteoarthritis and completed preoperative and 1-year postoperative PROMs were included. Distribution-based and anchored-based approaches were used to estimate MCID and PASS, respectively. The optimal cut-off point for PASS thresholds was calculated using the Youden index. RESULTS: MCID for HOOS-Pain and PS were calculated to be 9.2 and 9.3, respectively. The PASS threshold for HOOS-Pain and PS were ≥ 77.7 and ≥ 87.3, respectively. The current study identified several factors affecting postoperative achievement of thresholds. Baseline Mental Component Summary (MCS) scores were a predictor for achieving MCID for postoperative HOOS-Pain, achieving MCID for postoperative HOOS-PS, achieving PASS for postoperative HOOS-Pain, and achieving PASS for postoperative HOOS-PS. Furthermore, baseline HOOS-Pain was a significant predictor for achieving MCID for postoperative HOOS-PS, achieving PASS for postoperative HOOS-Pain, and achieving PASS for postoperative HOOS-PS. CONCLUSIONS: MCID and PASS thresholds were established for HOOS-Pain and PS domains following BHR with most patients achieving these clinically meaningful benchmarks. Additionally, several factors affecting achievement of MCID and PASS were identified, including modifiable risk factors that may allow clinicians to implement optimization strategies and further improve outcomes.

Effect of Elevated Acetabular Cup on Contact and Failure Analysis in Hip Implants for Different Microseparations and Cup Inclinations Under Routine Gait Activities Using In Silico Approach.

Objectives: The acetabular cup design plays a critical role in reducing contact stress between femur head acetabular cup. Many studies used ellipsoidal and spheroidal geometry in acetabular cup design to effectively reduce contact stress. The present study focuses on elevated acetabular cup rim with round corner design to reduce contact stress with round corner geometry. Methods: The cobalt chromium femur head and cup are considered for finite element (FE) model of hip resurfacing. The gait loads of routine activities of humans like normal walking, stair ascending and descending and sitting down and getting up gait activities are applied to the developed 3D FE model. Five microseparations of 0.5, 1, 1.5, 2 and 2.5 mm are considered in the present study. The acetabular cup inclination angle considered for this study are 35°, 45°, 55°, 65° and 75°. The contact stress and von Mises stress plot for each gait activities under these microseparations are analyzed for betterment of longevity of implants. Results: Overall elevated cup rim design helped in reducing contact stress to a greater extent than conventional cup with different geometries. Also, the predicted von Mises stress for all the parameters considered in the current study are well within the yield strength of CoCr material. Therefore, elevated cup rim could be used as a better alternative to spline and, ellipsoidal and circular geometries of cup.

Advances in imaging for pre-surgical planning in hip resurfacing arthroplasty.

BACKGROUND: Accurate preoperative templating is essential for the success of hip resurfacing arthroplasty (HRA). While digital radiograph is currently considered the gold standard, stereoradiograph and CT converted 3D methods have shown promising results. However, there is no consensus in the literature regarding the preferred modality for HRA templating, and angular measurements are often overlooked. Thus, this study aimed to: (1) compare the performances of different modality in implant sizing and angle measurements, (2) evaluate the measurement reproducibility, (3) assess the impact of severe osteoarthritis on femoral head sizing, and (4) based on the analysis above, explore the optimal imaging and planning strategy for HRA. HYPOTHESIS: An optimal imaging modality exists for HRA planning regarding implant sizing and angular measurements. MATERIALS AND METHODS: Preoperative imaging data from seventy-seven HRA surgeries were collected. Three raters performed templating using digital radiograph, stereoradiograph, and CT converted 3D models. Measurements for femoral head size, neck-shaft angle, and calcar-shaft angle were obtained. The femoral head sizing was compared to the intraoperative clinical decision. The reproducibility of measurements was assessed using the intraclass correlation coefficient (ICC). Correlations were examined between sizing disagreement and osteoarthritis grade (Tonnis Classification). RESULTS: Digital radiograph, stereoradiograph, and 3D techniques predicted one size off target in 27/77 (35%), 49/70 (70%), and 75/77 (97%) of cases, respectively, corresponding to 1.8±1.6 (0 to 5.67), 0.9±0.7 (0 to 2.67), and 0.4±0.4 (0 to 1.67) sizes off target, indicating statistically significant differences among all three modalities, with p-values all below 0.01. There were no statistically significant differences among the different modalities for angular measurements. Measurements showed moderate to excellent reproducibility (ICC=0.628-0.955). High-grade osteoarthritis did not impact image sizing in any modality (r=0.08-0.22, all p>0.05). DISCUSSION: CT converted 3D models were more accurate for implant sizing in HRA, but did not significantly outperform other modalities in angular measurements. Given the high costs and increased radiation exposure associated with CT, the study recommended using CT scans selectively, particularly for precise femoral head sizing, while alternative imaging methods can be effectively used for angular measurements. LEVEL OF EVIDENCE: III; retrospective comparative diagnostic study.

Kuntscher nail removal: Revision of a failed hip resurfacing above an incarcerated Kuntscher nail. A case report of a smart nail extraction technique through a custom-made instrumentation.

Removal of a retained and osseointegrated intramedullary femoral nail can represent a considerable problem, especially in the case of contemporary total hip arthroplasty or, even worse, in the case of revision hip arthroplasty. Usually, complex and invasive surgical techniques are required to remove incarcerated Kuntscher nails. We described a case of an incarcerated Kuntscher nail, inserted 39 years before, in a 75-year-old woman waiting for a revision total hip arthroplasty of a failed metal-on-metal hip resurfacing. A CT-based custom-made extra-long trephine reamer was designed and successfully used to easily extract the nail, leaving the proximal femur before a revision hip arthroplasty.

Assessing the Effects and Challenges of Total Hip Arthroplasty before Pregnancy and Childbirth: A Systematic Review.

Total hip arthroplasty is indubitably one of the most performed operations worldwide. On the other hand, especially in the western world, the average age that women get pregnant has raised confoundedly. Consequently, a steadily increasing number of women become pregnant after they had hip arthroplasty surgery, with copious potential implications. The amount of knowledge on this particular field is considered inadequate in the existing literature. This paper aims to augment clinicians understanding surrounding this topic. A systematic literature review was conducted in accordance with the PRISMA guidelines. Papers from various computerized databases were scrutinized. Article selection was carried out by three authors independently employing specific pre-determined inclusion and exclusion criteria, while disagreements were elucidated with the contribution of other authors. A patently limited number of research articles were detected from our rigorous literature review, with only 12 papers meeting the inclusion criteria. The vast majority of studies were small-scale and examined confined population groups. Most studies had been performed in Finland, utilizing data from nationwide registries. Women with previous history of total hip arthroplasty feature increased rates of c-section delivery, although vaginal labor can be attempted with certain precautions. Hip implants' survival does not appear to be affected from gestation, which is predominately well-tolerated from these women. Metal ion circulation in mothers' blood has not been proven to trigger substantial complications concerning either mothers or offspring. It can be considered safe for women with such medical history to get pregnant; however, further multinational studies and pertinent research on this field are vital to attain more solid inferences.

Is there still an indication for the Birmingham Hip Resurfacing in femoral head osteonecrosis?

PURPOSE: Osteonecrosis of the femoral head (ONFH) is a progressive hip disease. Hip resurfacing arthroplasty (HRA) is a preferred surgical procedure among hip arthroplasty performed in young patients. The aim of this study is to show the long-term clinical and radiological results of HRA procedures performed for patients suffering from ONFH. METHODS: Forty-five patients who underwent hip resurfacing with the diagnosis of femoral head osteonecrosis were included in the study. The Harris Hip Score (HHS) was used for clinical scoring of the patients. The blood chromium, cobalt, white blood cell (WBC) count, and CRP levels of patients were checked. Ultrasonography (USG) was performed for all patients at mid-term control checked for pseudo-tumours. For the radiological evaluation, acetabular inclination, stem shaft angle, prothesis-to-neck ratio, osteolysis zones, and heterotopic ossification were used. RESULTS: The mean age of the patients was 46.6 ± 9.3 years, and the mean follow-up period was 11.83 ± 2.9 years. The mean HHS was 90.3 ± 12.8 for final follow-up. The mean WBC value was 8.2 109/L, mean CRP value was 6.3 mg/L, mean chromium value was 4.9 µg/L, and mean cobalt value was 1.8 µg/L. Inclination changing 0.2°(p = 0.788), stem shaft angle changing 0.7°(p = 0.424), and neck-to-prosthesis ratio changing 0.01°(p = 0.075). No pseudo-tumours were detected in any patients in USG examination. CONCLUSION: HRA provides long-term implant survival and excellent clinical outcomes for end-stage ONFH patients with low complication rates.

Metal ion release after hip resurfacing arthroplasty and knee arthroplasty: a retrospective study of one hundred ninety-five cases.

PURPOSE: Hip arthroplasty with metal-on-metal bearings like hip resurfacing results in the release of metallic ions. In parallel, like every metallic implant, knee arthroplasty implants undergo passive corrosion. We analyzed blood levels of cobalt and chromium ions in patients who have a hip resurfacing arthroplasty and compared them to patients who have undergone knee arthroplasty at a minimum follow-up of one year. The hypothesis was that there is no difference in the ion release between hip resurfacing and knee arthroplasty. METHODS: Sixty-three patients who underwent knee arthroplasty were compared to a cohort of 132 patients who underwent hip resurfacing. The blood levels of cobalt and chromium ions were determined preoperatively and at six and 12 months postoperatively and then compared between groups. We analyzed the relationship between ion release and the change in clinical outcome scores (Harris Hip score, Oxford Hip score, Merle D'Aubigné Postel score, Oxford Knee score, International Knee Society score), the BMI, sex, physical activity, implant size and inclination of the acetabular implant (hip resurfacing patients only). Mixed linear models were used to assess the changes in ion blood levels over time. RESULTS: The cobalt blood levels were higher in the first 6 months in the resurfacing group (0.87 ug/L vs 0.67 ug/L; p = 0.011), while it was higher in the knee arthroplasty group at 12 months (1.20 ug/L vs 1.41 ug/L; p = 0.0008). There were no significant differences in chromium levels during the follow-up period. CONCLUSION: The increase in metal ion release after knee arthroplasty is as high as after hip resurfacing at the one year follow-up. The monitoring of this parameter probably should not be recommended in case of good clinicals outcomes.

Hip resurfacing: case closed? A bibliometric analysis of the past 10 years.

INTRODUCTION: Hip resurfacing (HR) was introduced as a potential alternative to total hip arthroplasty (THA), indicated predominantly for younger, high demand patients. The modern metal-on-metal implant was popularized in the 1990s and early 2000s and promised greater wear resistance. However, its popularity waned due to increased rates of complications related to metal toxicity including pseudo-tumors as well as the recall of many resurfacing implants. The purpose of this study was to conduct a bibliometric analysis and investigate the current trends in hip resurfacing literature. METHODS: Using the keywords "hip resurfacing," publications between 2012 and 2022 were identified on Web of Science Core Collection of Clarivate Analytics. Results were screened for relevance by three independent reviewers using title, abstract, and full text. The retrieved data were evaluated by the bibliometric method. Included articles were imported into CiteSpace 5.7.R1, 64-bit (Drexel University, Philadelphia, PA, USA), VOSviewer 1.6.15 (Leiden University, Leiden, the Netherlands), and the Online Analysis Platform of Literature Metrology to identify trends in publication. RESULTS: Search terms yielded 1200 results and 724 were included in final analysis. A steady decrease of publications was noted over the past decade with less than 40 articles published in 2020 and 2021. The Journal of Hip Arthroplasty (92), Hip International (74), and Clinical Orthopaedics and Related Research (54) published the most articles. Authors from the United States and the United Kingdom published the most studies. High-frequency keywords in co-occurrence and co-cited cluster analysis were metal-on-metal, metal ions, wear, pseudo-tumor, and revision, demonstrating that long-term concerns have been the focus of most recent studies. CONCLUSION: In conclusion, our bibliometric analysis allowed novel exploration and identification of the current research trends, contributions, and the distribution of publications exploring HR. The understanding of HR and the poor long-term outcomes of some resurfacing implants has improved significantly over the past decade, with the most recent focus on failure rates and long-term complications from metal debris. However, the breadth of literature has steadily declined in the past decade, and ultimately demonstrates the decline of scientific interest and focus on novel areas in hip resurfacing and a potential reached consensus.

Three-Dimensional Preoperative Planning Software for Hip Resurfacing Arthroplasty.

Three-dimensional planning of hip arthroplasty is associated with better visualisation of anatomical landmarks and enhanced mapping for preoperative implant sizing, which can lead to a decrease in surgical time and complications. Despite the advantages of hip resurfacing arthroplasty (HRA), it is considered a technically challenging procedure and associated with inaccurate implant placement. This study aimed to examine the validity, reliability, and usability of preoperative 3D Hip Planner software for HRA. Fifty random cases of various hip osteoarthritis severity were planned twice by two junior trainees using the 3D Hip Planner within a one-month interval. Outcome measures included femoral/cup implant size, stem-shaft angle, and cup inclination angle, and were assessed by comparing outcomes from 2D and 3D planning. An adapted unified theory of acceptance and use of technology (UTAUT) survey was used for software usability. Bland-Altman plots between 3D and 2D planning for stem-shaft and inclination angles showed mean differences of 0.7 and -0.6, respectively (r = 0.93, p < 0.001). Stem-shaft and inclination angles showed inter-rater reliability biases of around -2° and 3°, respectively. Chi-square and Pearson's correlation for femoral implant size showed a significant association between the two assessors (r = 0.91, p < 0.001). The 3D test-retest coefficient of repeatability for stem-shaft and inclination angles were around ±2° and ±3°, respectively, with a strong significant association for femoral implant size (r = 0.98, p < 0.001). Survey analyses showed that 70-90% agreed that 3D planning improved expectancy in four domains. 3D hip planner appears to be valid and reliable in preoperative HRA and shows significant potential in optimising the quality and accuracy of surgical planning.

Hip Resurfacing Arthroplasty: Past, Present and Future.

The history of hip resurfacing arthroplasty (HRA) has faced numerous challenges and undergone decades of evolution in materials and methods. These innovations have been translated to the successes of current prostheses and represent a surgical and mechanical achievement. Modern HRAs now have long term outcomes with excellent results in specific patient groups as demonstrated in national joint registries. This article reviews the key moments in the history of HRAs with specific emphasis on the lessons learnt, current outcomes and future prospects.

Mid-term clinical and radiographic outcome of metal-on-metal hip resurfacing through an anterolateral approach.

PURPOSE: The aim of this retrospective study was to evaluate the medium-term clinical and radiographic results of current generation metal-on-metal resurfacing prostheses performed through anterolateral approach. MATERIALS AND METHODS: Fifty-seven hips in 52 patients underwent resurfacing arthroplasty. Two patients died from unrelated causes, leaving 55 hips in 35 males (3 bilateral) and 15 females (2 bilateral), with a mean age at surgery of 56.2 years (range, 27-70 years). Clinical and radiographic assessment was carried out preoperatively and at follow-up in all the survived cases. The cumulative survival rate was determined according to the method of Kaplan-Meier. RESULTS: At a mean follow-up of 5.2 years (range, 1.8-9.1 years), 2 HRs of the same female patient were revised because of early loosening of the acetabular component. Deep venous thrombosis and transient femoral nerve palsy occurred both in 1 case. No specific complications of HR were observed. Average Harris hip score improved significantly from 59.8 points (range, 30.4-90.6) preoperatively to 93.7 points (range, 53-100) at the latest examination. Neck narrowing showed an average of 3.27%, but it never exceeded 10%. Nonprogressive acetabular radiolucencies and osteolysis were detected both in 2 hips. A high rate of patients (32, 60.4%) developed heterotopic ossifications, although low-grade in most cases (27, 84.4%). The cumulative survival rate at 9.1 years with revision for any reason as the end point was 93.0%. CONCLUSIONS: The early clinical and radiographic results of modern metal-on-metal hip resurfacing performed through an anterolateral approach are promising, but longer-term follow-up studies are necessary.

Hip Resurfacing in Teenagers.

BACKGROUND: The goals of hip resurfacing are to relieve pain, restore function, and preserve future reconstructive options. Hip resurfacing is an attractive and sometimes the only option when the femoral canal is blocked, making total hip arthroplasty (THA) difficult. Hip resurfacing also can be an attractive option for a teenager on the rare occasion when a hip implant is needed. METHODS: A cementless ceramic-coated femoral resurfacing implant matched with a highly cross-linked polyethylene acetabular bearing was used in 105 patients (117 hips) aged 12 to 19 years. The mean follow-up was 14 years (range, 5 to 25). No patients were lost to follow-up before 19 years. Osteonecrosis, residuals of trauma, developmental dysplasia, and childhood hip diseases were the common reasons requiring surgery. Patients were evaluated using patient-reported outcomes, patient acceptable symptom states (PASS), and implant survivorships. Radiographs and retrievals were also examined. RESULTS: There were 2 revisions (polyethylene liner exchange at 12 years and femoral revision for osteonecrosis at 14 years). The mean postoperative Hip Disability Osteoarthritis Outcome Score (HOOS) was 94 points (range, 80 to 100) and the mean Harris Hip Score (HHS) score was 96 points (range, 80 to 100). All patients achieved Minimal Clinically Important Difference improvement in their HHS and HOOS scores. There were 99 (85%) hip resurfacing procedures achieving a satisfactory PASS and 72 (69%) patients were active in sports. CONCLUSION: Hip resurfacing is a highly technical procedure. Careful implant selection is required. The meticulous preoperative planning, careful extensile surgical exposure, and exacting implant placement in this study likely contributed to the favorable results achieved. Hip resurfacing allows THA as a future option in patients where the lifetime revision rate is a major consideration.

Strategies for fixation of periprosthetic fragility fractures of the neck of femur below a well-functioning hip resurfacing arthroplasty: A case-series.

Introduction: Metal-on-metal Hip Resurfacing (HR) was performed in many young individuals as it conserved bone stock and had low wear rates, before it became less popular due to the detection of Adverse Reactions to Metal Debris. As such, many patients in the community have well-functioning HRs and as they age, the incidence of fragility fractures of the neck of femur around the existing implant is expected to increase. These fractures are amenable to surgical fixation as adequate bone stock remains in the head of the femur and the implants are well fixed. Case-series: We present a series of six cases which were treated by fixation using locked plates (3), dynamic hip screws (2) and cephalo-medullary nail (1). Four cases achieved clinical and radiographic union with good function. One case had a delayed union, though union was finally achieved at 23 months. One case had an early failure necessitating revision to a Total Hip Replacement after 6 weeks. Discussion: We highlight the geometrical principles of placing fixation devices under an HR femoral component. We have also conducted a literature search and present details of all case reports to date. Conclusion: Fragility per-trochanteric fractures under a well-fixed HR with good baseline function are amenable to fixation using a variety of methods including large screw devices that are commonly used in this location. Locked plates including variable angle locking designs should be kept available if needed.

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

BACKGROUND: Hip 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. METHODS: The 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. RESULTS: A 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. CONCLUSIONS: The 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.

Hip resurfacing arthroplasty in women: A novel ceramic device enables near normal gait function.

BACKGROUND: Gait function improves after Total Hip Arthroplasty (THA) but is not restored to normal levels. Metal-on-metal Resurfacing Arthroplasty (MoM-HRA) is an alternative to THA and has shown to restore normal levels gait function and physical activity but has been restricted to men owing to problems of metal-ion release. Ceramic HRA (cHRA) removes the cobalt-chrome bearing surfaces, thereby eliminating these specific metal-ion concerns and aiming to be safe for females. RESEARCH QUESTION: Is there a difference in gait function of female cHRA patients compared to female THA using subjective and objective measures? METHODS: Fifteen unilateral cHRA and 15 unilateral THA, age and BMI matched, completed patient reported outcome measures (PROMs) (Oxford Hip Score, EQ5d and MET score) and underwent gait analysis using an instrumented treadmill pre- (2-10 weeks) and post-operatively (52-74 weeks). Maximum walking speed (MWS), Vertical GRF of the stance phase, GRF symmetry index (SI) and spatiotemporal gait measures were recorded. Patients were compared to age, gender and BMI healthy controls (CON). RESULTS: There were no differences in PROMs or gait function between groups pre-operatively. Post- operatively, cHRA had a higher MET score (11.2 vs 7.1, p = 0.02) and a higher MWS (6.2 vs 6.8 km/hr, p = 0.003) compared to THA. cHRA had a similar GRF profile to CON, whereas THA had a reduced push-off force at 70-77 % of the stance phase compared to CON. At faster walking speeds of 6 km/hr walking speed, THA displayed an asymmetric GRF profile (SI<4.4 %) whereas the cHRA patients continued to display a symmetrical gait profile. cHRA was able to increase step length from pre-op levels (63 vs 66 cm, p = 0.02) and produced a larger step length compared to THA (73 vs 79 cm, p = 0.02). SIGNIFICANCE: Female cHRA returned to levels of gait function and activity similar to healthy controls unlike female THA.

Novel Use of an Accelerometer to Assess Load Asymmetry Over Time After Hip Resurfacing Arthroplasty.

BACKGROUND: There is limited knowledge regarding usage of wearable technology to guide return to sport after hip resurfacing arthroplasty (HRA). This study evaluated the use of accelerometers to identify when symmetry is restored between operative and nonoperative limbs. METHODS: A total of 26 primary HRA patients performed 5 validated physical tests before, 3 and 6 months after HRA: broad jump, double-leg vertical jump (DLVJ), hop test, lateral single-leg jump (LSLJ), and vertical single-leg jump. Impact load and average intensity data (g-force units) were collected using accelerometers. Strength data (pounds [lbs.]) for internal and external rotation were collected with a dynamometer. Univariate and correlation analyses analyzed interlimb asymmetries. RESULTS: At preoperation, there were significant impact load asymmetries for DLVJ (P = .008), hop test (P = .021), and LSLJ (P = .003) and intensity asymmetry for DLVJ (P = .010) and LSLJ (P = .003). At 3 months, there was impact load asymmetry for DLVJ (P = .005) and LSLJ (P = .005) and intensity asymmetry for broad jump (P = .020), hop test (P = .042), and LSLJ (P = .005). There were significant strength asymmetries at preoperation and 3 months postoperation for internal (P = .013) and external rotation (P = .037). All significant asymmetries indicated the nonoperative leg had greater output. No significant asymmetries were found for any exercises at 6 months postoperation. An increase in Harris Hip Score was significantly associated with a decrease in impact asymmetry (rs = -0.269, P = .006). CONCLUSION: Impact loads and strength reach interlimb symmetry at 6 months post-HRA. Wearable accelerometers provide useful metrics to distinguish limb asymmetries for recovery monitoring.

Metal-on-Metal Hips: Ten-Year Clinical and Radiographic Outcomes of the ADEPT Metal-on-Metal Hip Resurfacing and Modular Total Hip Arthroplasty.

BACKGROUND: The aim of this study is to update the 10-year follow-up survivorship and metal ions levels of a cohort of metal-on-metal (MoM) hip resurfacing (HR) and large-diameter-head (LDH) total hip arthroplasty (THA). METHODS: The study is a retrospective analysis of prospectively collected data that compared the outcomes of 24 MoM HR (21 patients) and 15 (11 patients) modular LHD MoM THA at >10 years follow-up. Baseline characteristics as well as intraoperative and postoperative information were collected, including complications, revisions, clinical and radiographic outcomes, and serum metal ions level (Cobalt, Chromium). Metal ion levels were compared using a two-tailed unpaired t-test and Wilcoxon signed-rank test (jamovi v2.3.3.0, Sydney, NSW, AU). RESULTS: No significant differences were detected in gender, BMI, and ASA score between the two groups. Patients in the modular THA group were significantly older (57 years vs. 46 years; p < 0.05). The HR overall survivorship was 91.7% (22 of 24 hips) with survivorship from implant failure and/or aseptic loosening and/or metal debris related 100% of problems. The modular THA overall survivorship was 86.7% (13 of 15 hips) with survivorship from implant aseptic loosening and metal ions complications of 93.4% (14 of 15 hips). No significant difference was noted when comparing clinical outcomes. Metal ions were significantly lower in the HR group (Co 25.8 nmol/L vs. 89 nmol/L; p < 0.001-Cr 33.5 nmol/L vs. 55.2 nmol/L; p = 0.026). CONCLUSION: Both implants reported excellent and comparable clinical outcomes at >10 years follow-up. The Adept HR reported remarkable survivorship, in line with the registry data, proving once again its reliability in young active males. The modular LDH THA, despite being discontinued, presented higher reliability and a lower failure rate when compared with similar withdrawn MoM implants. Trunnionosis did not appear to be a significant problem in this particular modular design.

Wear debris in metal-on-metal bearings and modular junctions : What have we learned from the last decades?

Metal-on-metal (MoM) bearing hip arthroplasty saw increasing utilization and peaked in the 1990s and early 2000s. Although the linear and volumetric wear rate for a MoM bearings was lower than its polyethylene counterpart, metal ion particles were found to be approximately 10â€¯× smaller and 500â€¯× higher in quantity compared to polyethylene wear debris. Research into these articulations have demonstrated their relationship to the formation of lymphocyte-mediated adverse local tissue reactions. The work-up for metal particle-associated conditions (metallosis) includes a thorough patient history and physical examination, blood laboratory studies for metal ion concentrations, and advanced imaging studies including magnetic resonance imaging (MRI). The treatment of metallosis and adverse local tissue reactions ranges from close serial observation to extensive debridement and full revision of arthroplasty components, when indicated.

A comparison of 2 cementing techniques in hip resurfacing using human femoral heads.

INTRODUCTION: Hip resurfacing remains a valid option in young male patients. The creation of the optimum cement mantle aids fixation of the femoral component. If the cement mantle is too thick the prosthesis can remain proud leading to early failure or if it penetrates too far into the femoral head, it may cause osteonecrosis. METHOD: 18 of 96 femoral heads collected from patients undergoing total hip arthroplasty were matched for their surface porosity. They were randomly allocated into 2 different cementing groups. Group 1 had the traditional bolus of cement technique, while group 2 had a modified cementing technique (swirl) where the inside of the femoral component was lined with an even layer of low viscosity cement. RESULTS: The traditional bolus technique had significantly greater cement mantle thickness in 3 of 4 zones of penetration (p = 0.002), greater and larger air bubble formation (6 of 9 in bolus technique vs. 1 in 9 in swirl technique, p = 0.05) and more incomplete cement mantles compared with the swirl technique. There was no relationship to femoral head porosity. CONCLUSION: The swirl technique should be used to cement the femoral component in hip resurfacing. Long-term clinical studies would conform if this translates into increased survivorship of the femoral component.