Isolated Liner Exchange in Total Hip Arthroplasty at a Mean of 13 Years of Follow-up: Does Fixation Technique Matter?

BACKGROUND: Isolated liner exchange is an option to address polyethylene wear after total hip arthroplasty (THA). The liner can be fixed with either the original locking mechanism or cemented into the acetabular cup. Whether the method used for liner fixation has any bearing on the outcomes in the first and second decade after surgery is still unclear. METHODS: Data for all patients who had undergone isolated liner exchange surgery in our institution between April 1995 and January 2015 were retrieved. Patients were classified according to the type of polyethylene liner (conventional or highly crosslinked polyethylene) and the locking mechanism used (original locking mechanism or cemented). Survivorship and revision rates were compared among different subgroups. A total of 118 isolated liner exchanges were performed and patients had a mean duration of follow-up of 13 years (range, 5 to 25). RESULTS: Overall estimated mean survivorship was 17 years. Use of highly crosslinked polyethylene (HXLPE) had a lower re-revision rate compared to conventional liners (10.5 versus 46.9%) (P < .001). The re-revision rate of exchanges using HXLPE was not affected by the type of fixation (original locking mechanism 11.1 versus cement 10.0%, P = .868). Conversely, using the original locking mechanism with a conventional liner had a higher re-revision rate compared to cemented conventional liners (58.3 versus 12.5%) (P = .024). CONCLUSION: HXLPE liners should be used in insert exchange surgery whenever possible. Re-revision rate of exchanges using HXLPE was not affected by the fixation technique used. Cementing an insert into an acetabular component is associated with good survivorship at a mean of 13 years follow-up.

Metal-on-crosslinked polyethylene in total hip arthroplasty - an excellent combination at fifteen to twenty years of follow-up.

PURPOSE: Cross-linked polyethylene (PE) has been used with great clinical success in total hip arthroplasty (THA) since its debut in the late 1990's. However, reports regarding this bearing couple near the end of its second decade of service are still scant. The aim of this study was to first determine the long term clinical and radiological results and second Investigate what factors affect wear rates using a metal-on-crosslinked PE bearing articulation. METHODS: 55 THAs using a single brand of cross-linked liner, cementless cup and 28 mm hip ball were performed in 44 patients. Age, sex, Charlson Comorbidity Index (CCI) and need for revision surgery were recorded. Linear and volumetric wear was determined using the Martell method. RESULTS: Mean age at operation was 51.2 (29-73 ± 12.1) years. Mean duration of follow-up was 16.9 years (range 15.0-20.1 ± 1.1 years). Osteolysis was not present in the latest follow-up radiographs. Median linear and volumetric wear rate was 0.038 mm/year (95% CI 0.032-0.047) and 7.115mm3/year (95% CI 6.92-17.25) respectively. Acetabular component position was not found to be related to both linear and volumetric wear. No significant difference was found in the linear and volumetric wear rates of thinner and thicker liners (8 mm or below and > 8 mm) (p = 0.849 and p = 0.64 respectively). CONCLUSION: Metal-on-crosslinked PE is associated with low linear and volumetric wear rates which has virtually obviated osteolysis and has translated to excellent survivorship even at long term follow up. In-vivo oxidation does not appear to be of clinical concern at this point.

Exploring the relationship between pain intensity and knee moments in participants with medial knee osteoarthritis: a cross-sectional study.

BACKGROUND: High biomechanical loading is believed to be a risk factor to pain in people with knee osteoarthritis (OA), but controversial findings have been reported on the relationship between external knee adduction moment (KAM) and pain. A more comprehensive analysis considering other factor such as external knee flexion moment (KFM) could help better reveal this relationship. This study explored the relationship between external knee adduction moment and pain intensity in participants with knee osteoarthritis (OA) using an integrated path analysis model. METHODS: This was a cross-sectional study based on laboratory setting. Forty-seven participants with clinical and radiographic medial knee OA were analyzed for their external knee adduction moment (KAM) and knee flexion moment (KFM) during walking using a motion analysis system. Pain intensity was measured by visual analogue scale (VAS) and the pain subscale of the Knee Injury and Osteoarthritis Outcome Score. Varus/valgus alignment was captured and quantified using a bi-planar X-ray system. Using a path analysis model, the relationships between pain intensity, KAM, KFM, OA radiographic severity, knee varus angle and walking speed were examined. RESULTS: The proposed path model met the goodness-of-fit criteria. Based on this model, KAM had a negative effect on VAS pain indirectly through the mediation of KFM. The model indicated KAM and KFM were negatively related to one another; and KFM was positively related to VAS. The KAM index, defined as (KAM/ (KAM + KFM)), was negatively related to VAS. CONCLUSIONS: Path analysis enabled the construction of a more integrated pathokinematic framework for people with knee OA. The KAM index which reflected the load sharing on the frontal and sagittal planes also revealed its relationship with pain. Re-distribution of mechanical loading from frontal to sagittal plane might be a strategy for pain avoidance associated with mechanical irritation.

Combination Effect of High-Dose Preoperative and Periarticular Steroid Injection in Total Knee Arthroplasty. A Randomized Controlled Study.

BACKGROUND: Postoperative pain remains a major barrier to a patient's recovery after total knee arthroplasty (TKA). Periarticular corticosteroids in local infiltration analgesics (LIA) and high-dose intravenous corticosteroids have individually shown to improve pain control after TKA. However, potential interactions between them have not been investigated. This study aims to evaluate any combination effect of both routes of corticosteroids in TKA. METHODS: This is a double-blinded, paired, randomized controlled trial involving 1-stage bilateral TKAs. All received 16 mg of dexamethasone intravenously. One knee was randomized to receive LIA with 40 mg of triamcinolone, while the other knee receives LIA without corticosteroids. For each patient, one knee was affected by intravenous steroids only, while the other was under the combined effect of intravenous and periarticular steroids (IVPAS). Knee pain, Southampton wound scores, and functional knee scores (Knee Society Knee Score and Oxford Knee Scores) were compared between knees of the same patient. RESULTS: Forty-six patients (92 TKAs) were included. IVPAS knees showed significantly lower visual analog scale scores from day 1 to 6 weeks (P < .05) and a larger range of movement from day 2 to 4 (P < .05). IVPAS knees achieved active straight leg raise earlier than intravenous steroids (1.6 vs 2.3 days, P < .05). No differences in Southampton wound scores and functional knee scores for up to 1 year. CONCLUSION: Combining intravenous and periarticular corticosteroids improved pain control and recovery after TKA with no increase in wound complications up to 1 year.

Preoperative dexamethasone for pain relief after total knee arthroplasty: A randomised controlled trial.

BACKGROUND: Corticosteroids can reduce pain but the optimal dose and safety profiles are still uncertain. OBJECTIVE: This study aimed to evaluate two different doses of dexamethasone for pain management and their side effects after total knee arthroplasty. DESIGN: A prospective randomised, controlled trial. SETTING: A tertiary teaching hospital in Hong Kong. PATIENTS: One hundred and forty-six patients were randomly allocated to one of three study groups. INTERVENTIONS: Before operation, patients in group D8, D16 and P received dexamethasone 8 mg, dexamethasone 16 mg and placebo (0.9% saline), respectively. MAIN OUTCOME MEASURES: The primary outcome was postoperative pain score. Secondary outcomes were opioid consumption, physical parameters of the knees and side effects of dexamethasone. RESULTS: Compared with placebo, group D16 patients had significantly less pain during maximal active flexion on postoperative day 3 [-1.3 (95% CI, -2.2 to -0.31), P = 0.005]. There was also a significant dose-dependent trend between pain scores and dexamethasone dose (P = 0.002). Compared with placebo, patients in group D16 consumed significantly less opioid [-6.4 mg (95% CI, -11.6 to -1.2), P = 0.025] and had stronger quadriceps power on the first three postoperative days (all P < 0.05). They also had significantly longer walking distance on postoperative day 1 [7.8 m ([95% CI, 0.85 to 14.7), P = 0.023] with less assistance during walking on the first two postoperative days (all P < 0.029) and significantly better quality-of-recovery scores on postoperative day 1 (P = 0.018). There were significant dose-dependent trends between all the above parameters and dexamethasone dose (all P < 0.05). No significant differences were found in the incidence of chronic pain or knee function 3, 6 and 12 months postoperatively. CONCLUSION: Dexamethasone 16 mg given before total knee arthroplasty led to a reduction in postoperative pain, less opioid consumption, stronger quadriceps muscle power, better mobilisation and better overall quality-of-recovery after operation. No long-term improvement in reduction in pain and function of the knee was found. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02767882.

Ten- to Sixteen-Year Follow-Up of Highly Cross-Linked Polyethylene in Total Hip Arthroplasty: What Factors Affect Wear?

BACKGROUND: Increase in acetabular cup abduction in total hip arthroplasty (THA) using conventional polyethylene is associated with greater linear wear. Whether this relationship holds true for highly crosslinked liners, particularly with long-term follow-up, is still controversial. The effect of liner thickness on wear of highly cross-linked liners also remains to be clarified.This study sought to determine (1) the long-term clinical and radiological performance of highly cross-linked polyethylene in THA and (2) the effect of acetabular component positioning, polyethylene thickness, and patient demographics on wear. METHODS: Ninety-three THAs using a 28-mm hip ball, single brand of highly cross-linked polyethylene liner, and cementless cup were performed in 87 patients. Clinical outcomes were evaluated using the Harris Hip Score and need for revision surgery. Linear and volumetric wear, presence of osteolysis, and cup abduction angle were assessed. RESULTS: The mean age at operation was 51.4 years. The mean duration of follow-up was 12.7 years (10-16 years). Patients aged >50 years had higher rates of linear wear than those aged <50 years (P = .015). Positive correlation was found between cup abduction angle (P = .014) and cup version (P = .035) with a linear wear rate. Thinner liners (≤7 mm) had similar rates of linear and volumetric wear as thicker liners (≥8 mm) (P = .447). CONCLUSION: This is the only study to demonstrate a positive significant relationship between cup abduction angle and version with linear wear rate in THA with at least 10 years of follow-up. Liner thickness was not found to affect wear rates.

Does Barbed Suture Lower Cost and Improve Outcome in Total Knee Arthroplasty? A Randomized Controlled Trial.

BACKGROUND: Wound closure is key to prevent infection, facilitate immediate rehabilitation, and improve efficiency of total knee arthroplasty (TKA). Continuous knotless suturing with barbed suture can potentially save time and distribute tension more evenly. However, its role in TKA in terms of cost-effectiveness and wound complications is not clear. This study aims at comparing barbed and traditional sutures' wound closure time and cost in primary TKA. METHODS: One hundred nine knees were randomized into either barbed or traditional group. Synthetic absorbable sutures (Vicryl, Ethicon Inc) and bidirectional barbed sutures (Stratafix, Ethicon Inc) were used. Arthrotomy and subcutaneous wound closure time, wound complications, and rehabilitation parameters in terms of range of motion and Knee Society Score were compared. Patients were followed up to 3 months. RESULTS: Traditional sutures had significantly more positive leak tests (10 vs 2, P value <.05) and wound complications (11 vs 2, P value <.05). No differences in range of motion and Knee Society Score were noted. Arthrotomy and subcutaneous closure time were significantly shorter with barbed sutures (arthrotomy 325 seconds vs 491 seconds; subcutaneous 306 seconds vs 381 seconds, P value <.05). Concerning cost of suture material and operation time, barbed suture on average saved USD 48.7 per TKA in our local institute. CONCLUSION: Bidirectional barbed suture improves the cost-effectiveness of TKA through reducing wound closure time and wound complications.

Comparison between patient-specific instruments and conventional instruments and computer navigation in total knee arthroplasty: a randomized controlled trial.

PURPOSE: The current study investigated the accuracy in achieving proper lower limb alignment and individual component positions after total knee arthroplasty (TKA) with 3 different instrumentation techniques. It was hypothesized that patient-specific instruments (PSI) would achieve more accurate lower limb alignment and component positions compared to conventional instruments (CON). METHODS: Ninety knees in 81 patients were randomized in 1:1:1 ratio into CON, computer navigation (NAV) and PSI groups to receive TKA. The surgical routines were standardized. The lower limb mechanical axis and individual component positions were assessed on standard radiographs. Tourniquet time, operation time and patients' functional scores were documented. RESULTS: Conventional instruments and PSI were more likely to result in an excessively flexed femoral component (p = 0.001) compared to NAV. Number of outliers in postoperative lower limb alignment, and other components positions in the coronal and sagittal plane showed no statistically significant difference. The mean tourniquet time and operation time was significantly shorter in CON and PSI groups than NAV group (p < 0.001). Four early complications occurred in the PSI group (p = 0.015). At 3-month follow-up, there was no difference in terms of the knee range of motion and patients' function among the 3 groups. CONCLUSION: No significant radiological and clinical benefit could be demonstrated in using PSI over CON or NAV in TKA. Routine use of PSI is not recommended because of the extra cost and waiting time. LEVEL OF EVIDENCE: I.

Effect of tibial drill-guide angle on the mechanical environment at bone tunnel aperture after anatomic single-bundle anterior cruciate ligament reconstruction.

PURPOSE: The tibial drill-guide angle in anterior cruciate ligament (ACL) reconstruction influences the tunnel placement and graft-tunnel force, and is potentially associated with post-operative tunnel widening. This study aimed to examine the effect of the drill-guide angle on the stress redistribution at the tibial tunnel aperture after anatomic single-bundle ACL reconstruction. METHODS: A validated finite element model of human knee joint was used. The tibial tunnel with drill-guide angle ranging from 30° to 75° was investigated. The post-operative stress redistribution in tibia under the compressive, valgus, rotational and complex loadings was analysed. RESULTS: Compressive loading played a leading role on the stress redistribution at intra-articular tibial tunnel aperture. After ACL reconstruction, stress concentration occurred in the anterior and posterior regions of tunnel aperture while stress reduction occurred in the lateral and posteromedial regions under the compressive loading. Stress redistribution was partially alleviated by using the drill-guide angle ranging from 55° to 65°. CONCLUSIONS: The present study quantified the effect of bone tunnel drill-guide angle on the post-operative stress redistribution. This phenomenon potentially contributed to tunnel widening. A tunnel drill-guide angle ranging from 55° to 65° was proposed based on the biomechanical rationale. It could serve as a helpful surgical guide for ACL reconstruction.

Reducing edge loading and alignment outliers with image-free robotic-assisted unicompartmental knee arthroplasty: a case controlled study.

BACKGROUND: Survivorship of medial unicompartmental knee arthroplasty (UKA) is technique-dependent. Correct femoral-tibial component positioning associates with improved survivorship. Image-free robotic-assisted unicompartmental knee arthroplasty enables preoperative and intraoperative planning of alignment and assessment of positioning prior to execution. This study aimed to compare the radiological outcomes between robotic-assisted UKA (R-UKA) and conventional UKA (C-UKA). METHODS: This retrospective case control study involved 140 UKA (82 C-UKA and 58 R-UKA) performed at an academic institution between March 2016 to November 2020, with a mean follow-up of 3 years. Postoperative radiographs were evaluated for mechanical axis and femoral-tibial component position. Component position was measured by two methods: (1) femoral-tibial component contact point with reference to four medial-to-lateral quadrants of the tibial tray and (2) femoral-tibial component contact point deviation from the center of the tibial tray as a percentage of the tibial tray width. Baseline demographics and complications were recorded. RESULTS: There was a higher mean component deviation in C-UKA compared with R-UKA using method 2 (17.2% vs. 12.8%; P = 0.007), but no difference in proportion of zonal outliers using method 1 (4 outliers in C-UKA, 5.1% vs. 1 outlier in R-UKA, 1.8%; P = 0.403). R-UKA showed no difference in mean mechanical alignment (C-UKA 5° vs. R-UKA 5°; P = 0.250). 2-year survivorship was 99% for C-UKA and 97% for R-UKA. Mean operative time was 18 min longer for R-UKA (P < 0.001). CONCLUSION: Image-free robotic-assisted UKA had improved component medio-lateral alignment compared with conventional technique.

Promising short-term outcomes of free-hand burring technique to implant second-generation metaphyseal cone in Asian knees - a case series.

BACKGROUND: The second-generation metaphyseal cone was useful in managing bone defects in revision knee arthroplasty. However, due to the anatomical constraints in Asian osteometry, the authors utilized a novel free-hand burring technique instead of cannulated reaming for bone preparation. We reported the short-term outcomes of our surgical techniques specific to Asian osteometry. METHODS: We conducted a case series by consecutively recruiting 13 female and 12 male patients (involving 25 knees), with a mean age of 71 years (range, 54-88 years). The patients underwent revision total knee arthroplasty during the period from April 2017 to June 2022. Twenty-three tibial cones and 4 femoral cones using free-hand burring technique were implanted. The mean follow-up duration was 51 months (range 18-80 months). Due to the relatively small bone size and meta-diaphyseal center mismatch in the Asian knees, the free-hand burring technique instead of the cannulated reaming technique was adopted in preparing for cone implantation. The clinical outcomes were knee ranges of motion, the Knee Society Knee scores (KSS), end-of-stem pain, infection, and the need for revision surgery. The radiological outcomes included osteointegration, fracture, and loosening. RESULTS: Mean knee range of motion improved from 83 degrees (range 0°-120°) preoperatively to 106 degrees (range 60°-125°) postoperatively (P < 0.001). Mean KSS improved significantly from 29 (range 0-70) to 69 (range 5-100) (P < 0.001). All cones were osteointegrated. One case had transient end-of-stem pain, two developed intraoperative minor femoral fractures and one suffered from recurrent infection that did not require cone revision. Cone revision-free survivorship was 100%. There was no aseptic loosening. CONCLUSIONS: The second-generation cone implanted with free-hand burring bone preparation yielded promising short-term outcomes in Asian knees.

Comparison of the Cost-Effectiveness and Safety between Staged Bilateral Total Knee Arthroplasty and Simultaneous Bilateral Total Knee Arthroplasty: A Retrospective Cohort Study between 2001 and 2022.

A substantial proportion of Hong Kong's aging population suffers from osteoarthritis in both knees. Bilateral total knee arthroplasty (BTKA) is a surgical option for addressing this condition and can be performed via two approaches: simultaneous BTKA (SimBTKA) and staged BTKA (StaBTKA). We compared the cost-effectiveness and safety of these two methods in our institution. We retrospectively reviewed 2,372 patients (SimBTKA, 772; StaBTKA, 1,600; females, 1,780; males, 592; mean age at SimBTKA, 70.4 ± 7.99 years; mean age at StaBTKA, 66.4 ± 7.50 years; p < 0.001) who underwent BTKA in our institution from 2001 to 2022. Patients were categorized according to the surgical approach. Patients undergoing BTKA in our institution were included. Particularly for SimBTKA, patients were assessed by anesthetists to be medically fit before undergoing the procedure according to their age, American Society of Anesthesiologists status, and osteoarthritis severity. The primary outcome was the length of stay (LOS) after surgery. The secondary outcomes were the 30-day unintended readmission, intensive care unit (ICU) admission, and death. SimBTKA had a shorter mean total LOS (acute hospital + rehabilitation center; SimBTKA, 13.09 days; StaBTKA, 18.12 days; p < 0.001) and mean LOS in acute hospital (SimBTKA, 7.70 days; StaBTKA, 10.42 days; p < 0.001). However, no significant difference was found in the mean LOS in rehabilitation centers (SimBTKA, 5.47 days; StaBTKA, 6.32 days; p > 0.05) between the two approaches. The 30-day unintended readmission rate was lower in SimBTKA (SimBTKA, 2.07%; StaBTKA, 3.30%; odds ratio [OR] = 1.60; p > 0.05) but statistically insignificant. SimBTKA was less costly than StaBTKA by US$ 8,422.22 per patient. No significant differences in ICU admission and death rates were found (p > 0.05) between the two groups. SimBTKA had a shorter LOS and lower cost than StaBTKA and comparable complication rates. Therefore, SimBTKA should be indicated in medically stable patients.

Preoperative weight loss interventions before total hip and knee arthroplasty: a systematic review of randomized controlled trials.

BACKGROUND: The high co-prevalence of obesity and end-stage osteoarthritis requiring arthroplasty, with the former being a risk factor for complications during arthroplasty, has led to increasing interest in employing preoperative weight loss interventions such as bariatric surgery and diet modification. However, the current evidence is conflicting, and this study aimed to investigate the effect of weight loss intervention before arthroplasty in prospective randomized controlled trials. METHODS: Four electronic databases (MEDLINE, EMBASE, Web of Science, and Cochrane Central Register of Controlled Trials) were searched for prospective randomized controlled trials that compared weight loss interventions with usual care from inception to October 2023 by following the PRISMA guidelines. The Cochrane risk of bias tool and GRADE framework were used to assess the quality of the studies. Meta-analyses were performed when sufficient data were available from 2 or more studies. RESULTS: Three randomized controlled trials involving 198 patients were identified. Two studies employed diet modification, and one study utilized bariatric surgery. All three studies reported significant reductions in body weight and body mass index (BMI), and intervention groups had fewer postoperative complications. There was no difference in the length of stay between the intervention group and the control group. Variable patient-reported outcome measures were used by different research groups. CONCLUSION: Weight loss intervention can achieve significant reductions in body weight and body mass index before arthroplasty, with fewer postoperative complications reported. Further studies with different populations could confirm the effect of these interventions among populations with different obesity characteristics.

Subchondral bone expansion in advanced knee osteoarthritis: Relation with radiographic severity and role in surgical decision-making.

Background: Joint space width (JSW) is a traditional imaging marker for knee osteoarthritis (OA) severity, but it lacks sensitivity in advanced cases. We propose tibial subchondral bone area (TSBA), a new CT imaging marker to explore its relationship with OA radiographic severity, and to test its performance for classifying surgical decisions between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA) compared to JSW. Methods: We collected clinical, radiograph, and CT data from 182 patients who underwent primary knee arthroplasty (73 UKA, 109 TKA). The radiographic severity was scored using Kellgren-Lawrence (KL) grading system. TSBA and JSW were extracted from 3D CT-reconstruction model. We used independent t-test to investigate the relationship between TSBA and KL grade, and binary logistic regression to identify factors associated with TKA risk. The accuracy of TSBA, JSW and established classification model in differentiating between UKA and TKA was assessed using AUC. Results: All parameters exhibited inter- and intra-class coefficients greater than 0.966. Patients with KL grade 4 had significantly larger TSBA than those with KL grade 3. TSBA (0.708 of AUC) was superior to minimal/average JSW (0.547/0.554 of AUC) associated with the risk of receiving TKA. Medial TSBA, together with gender and Knee Society Knee Score, emerged as independent classification factors in multivariate analysis. The overall AUC of composite model for surgical decision-making was 0.822. Conclusion: Tibial subchondral bone area is an independent imaging marker for radiographic severity, and is superior to JSW for surgical decision-making between UKA and TKA in advanced OA patients.

The accuracy of sizing of the femoral component in total knee replacement.

PURPOSE: Femoral sizing in total knee replacement is important. Either undersizing or oversizing may result in deleterious effects to the clinical outcome after the surgery. There has been no study on the precision and accuracy of femoral sizing and the effect of measurement at different landmarks over the distal femur. This study assesses the intra-observer and inter-observer error of femoral sizing and identifies the effect of the placement site of the anterior referencing tool on femoral sizing. METHODS: Five investigators with different clinical experience measured the femoral size of 10 cadaveric specimens twice using three anterior referencing tool. The measurement of the femoral size was repeated at nine designated points on the anterior cortex of the cadaveric femora. RESULTS: Excellent intraobserver and interobserver agreements were obtained using the three anterior referencing tools. When the size on which the majority agreed was regarded as the actual size of the specimen, measurement at the nine designated points on the anterior cortex showed a deviation from the actual size from 6.2 to 46.2 %. Placing the femoral sizer stylus at the middle and 2 cm above the proximal margin of the anterior femoral condyle yielded the highest precision and accuracy. CONCLUSION: Regardless of the experience of the surgeons, measurement of the femoral size using the three anterior referencing tools is very accurate. Placing the stylus of the femoral sizer at the middle and 2 cm above the proximal margin of the anterior femoral condyle best reflects the actual size of the femur. LEVEL OF EVIDENCE: Experimental study.

Two-stage Partial Component Retention and Interim Cemented Liner for Infected Total Hip Arthroplasty: A Case Report.

Introduction: There is interest in partial exchange for infected total hip arthroplasty, as an alternative to complete removal of components in a traditional two-stage revision. Partial exchange avoids the difficulty of removing a well-fixed component and its associated bone loss. Case Report: We report a case of a 61-year-old male patient with an infected total hip arthroplasty, who underwent a two-stage partial exchange, with retention of the well-fixed femoral stem, and an interim cemented liner. He had excellent function and no infection recurrence at 4 years of follow-up. Conclusion: Two-stage partial exchange with interim cemented liner could be an effective option for infected total hip arthroplasty.

Robotic arm-assisted unicondylar knee arthroplasty resulted in superior radiological accuracy: a propensity score-matched analysis.

INTRODUCTION: Unicompartmental knee arthroplasty (UKA) is an effective surgical treatment for medial compartment arthritis of the knee, yet surgical outcomes are directly related to surgical execution. Robotic arm-assisted surgery aims to address these difficulties by allowing for detailed preoperative planning, real-time intraoperative assessment and haptic-controlled bone removal. This study aimed to compare the clinical and radiological outcomes between conventional manual mobile bearing and robot arm-assisted fixed bearing medial UKA in our local population. MATERIALS AND METHODS: This is a retrospective case-control study of 148 UKAs performed at an academic institution with a minimum of 1-year follow-up. 74 robotic arm-assisted UKAs were matched to 74 conventional UKAs via propensity score matching. Radiological outcomes included postoperative mechanical axis and individual component alignment. Clinical parameters included a range of motion, Knee Society knee score and functional assessment taken before, 6 and 12 months after the operation. RESULTS: Robot arm-assisted UKA produced a more neutral component coronal alignment in both femoral component (robotic -0.2 ± 2.8, manual 2.6 ± 2.3; P = 0.043) and tibial component (robotic -0.3 ± 4.0, manual 1.7 ± 5.3; P < 0.001). While the postoperative mechanical axis was comparable, robot arm-assisted UKA demonstrated a smaller posterior tibial slope (robotic 5.7 ± 2.7, manual 8.2 ± 3.3; P = 0.02). Clinical outcomes did not show any statistically significant differences. CONCLUSION: Compared with conventional UKA, robotic arm-assisted UKA demonstrated improved component alignment and comparable clinical outcomes. Improved radiological accuracy with robotic-arm assistance demonstrated promising early results.

Prediction of Total Knee Arthroplasty Sizes with Demographics, including Hand and Foot Sizes.

Anticipating implant sizes before total knee arthroplasty (TKA) allows the surgical team to streamline operations and prepare for potential difficulties. This study aims to determine the correlation and derive a regression model for predicting TKA sizes using patient-specific demographics without using radiographs. We reviewed the demographics, including hand and foot sizes, of 1,339 primary TKAs. To allow for comparison across different TKA designs, we converted the femur and tibia sizes into their anteroposterior (AP) and mediolateral (ML) dimensions. Stepwise multivariate regressions were performed to analyze the data. Regarding the femur component, the patient's foot, gender, height, hand circumference, body mass index, and age was the significant demographic factors in the regression analysis (R-square 0.541, p < 0.05). For the tibia component, the significant factors in the regression analysis were the patient's foot size, gender, height, hand circumference, and age (R-square 0.608, p < 0.05). The patient's foot size had the highest correlation coefficient for both femur (0.670) and tibia (0.697) implant sizes (p < 0.05). We accurately predicted the femur component size exactly, within one and two sizes in 49.5, 94.2, and 99.9% of cases, respectively. Regarding the tibia, the prediction was exact, within one and two sizes in 53.0, 96.0, and 100% of cases, respectively. The regression model, utilizing patient-specific characteristics, such as foot size and hand circumference, accurately predicted TKA femur and tibia sizes within one component size. This provides a more efficient alternative for preoperative planning.

Application of machine learning in the prevention of periprosthetic joint infection following total knee arthroplasty: a systematic review.

BACKGROUND: Machine learning is a promising and powerful technology with increasing use in orthopedics. Periprosthetic joint infection following total knee arthroplasty results in increased morbidity and mortality. This systematic review investigated the use of machine learning in preventing periprosthetic joint infection. METHODS: A systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed was searched in November 2022. All studies that investigated the clinical applications of machine learning in the prevention of periprosthetic joint infection following total knee arthroplasty were included. Non-English studies, studies with no full text available, studies focusing on non-clinical applications of machine learning, reviews and meta-analyses were excluded. For each included study, its characteristics, machine learning applications, algorithms, statistical performances, strengths and limitations were summarized. Limitations of the current machine learning applications and the studies, including their 'black box' nature, overfitting, the requirement of a large dataset, the lack of external validation, and their retrospective nature were identified. RESULTS: Eleven studies were included in the final analysis. Machine learning applications in the prevention of periprosthetic joint infection were divided into four categories: prediction, diagnosis, antibiotic application and prognosis. CONCLUSION: Machine learning may be a favorable alternative to manual methods in the prevention of periprosthetic joint infection following total knee arthroplasty. It aids in preoperative health optimization, preoperative surgical planning, the early diagnosis of infection, the early application of suitable antibiotics, and the prediction of clinical outcomes. Future research is warranted to resolve the current limitations and bring machine learning into clinical settings.

The role of telemedicine in joint replacement surgery? An updated review.

The usage of telemedicine and telehealth services has grown tremendously and has become increasingly relevant and essential. Technological advancements in current telehealth services have supported its use as a viable alternative tool to conduct visits for consultations, follow-up, and rehabilitation in total joint arthroplasty. Such technology has been widely implemented, particularly during the coronavirus 2019 (COVID-19) pandemic, to deliver postoperative rehabilitation among patients receiving total joint arthroplasty (TJA), further demonstrating its feasibility with a lower cost yet comparable clinical outcomes when compared with traditional care. There remains ample potential to utilize telemedicine for prehabilitation to optimize the preoperative status and postoperative outcomes of patients with osteoarthritis. In this review, various implementations of telemedicine within total joint arthroplasty and future application of telemedicine to deliver tele-prehabilitation in TJA are discussed.