Questionnaire on the perceptions of patients about total knee replacement

The effect of adductor canal block on outcomes of total knee arthroplasty: A single centre, historical cohort study

Background

Adductor canal blocks (ACBs) have been associated with reduced pain following total knee arthroplasty (TKA). There is a paucity of evidence regarding whether these early differences impact longer term outcomes. This study aimed to identify whether using ACB in TKA was associated with improvements in both early and late outcomes.

Methods

Patients who underwent a unilateral TKA between 2021 and 2022 were retrospectively assessed for pain scores, time to first mobilization and opioid use over the first 72 h. At 6 weeks, complications, pain scores and opioid use were assessed. At 12 months validated patient reported outcome measures (PROMs) and patient satisfaction with their surgery were assessed.

Results

262 unilateral TKA, of whom 129 received ACB (ACB group) and 133 did not (control group) were assessed. The ACB group had significantly lower median day 1 pain (median difference -0.44 (-0.09 to -0.79), p = 0.015). There was no significant difference between groups for pain after 24 h, time to mobilization or opioid use over 72 h. There was no significant difference in pain (p = 0.892), opioid use (p = 0.913) or complications (p = 0.348) at 6 weeks, or median change in PROMs (p = 0.436 and p = 0.307), opioid use (p = 0.187), or satisfaction with surgery (p = 0.262) at 12 months.

Conclusion

ACBs were associated with a clinically insignificant difference in median pain on day 1. there was no association with pain after 24 h, opioid use, time to mobilization or longer term outcomes. Our findings do not support the use of routine ACB during TKA.

Smart Knee Implants and Functional Outcome for Total Knee Arthroplasty

Smart knee implants integrate advanced sensor-based technologies, forming a unique technology-embedded total knee arthroplasty (TKA) implant. Such implants introduce the ability to capture new elements of patient-related data for use in the context of recovery in real time including subjective reported outcomes and objective outcomes related to range of motion, and gait parameters. This technology allows for real-time data capture and patient-specific insights, creating opportunities to optimize postoperative care.This brief narrative review discusses the foundations and origin of technology-embedded implants, beginning with research-related roots relating to the derivation of fundamental knee joint force measurements. Analyzing the current market of implants, the present review investigates the technological capacities of modern designs including form and function. Further discussed is an evaluation of smart knee implant effectiveness, focusing on its impact on recovery outcomes such as patient-reported outcome measures (PROMs), functional improvement, gait patterns, and patient adherence/satisfaction.Smart implants represent a significant technological advancement in personalized care, leveraging real-time data including joint motion, alignment, and patient motion to assist surgeons in optimizing rehabilitation protocols. These implants provide insights into recovery progression postoperatively, with the potential for early identification of at-risk individuals. Preliminary studies demonstrate favorable patient outcomes and satisfaction, although further research is necessary to establish the long-term benefits and efficacy of smart knee implants.

The effect of Kellgren-Lawrence grade on functional outcome following medial unicompartmental knee arthroplasty in patients with partial thickness cartilage loss

INTRODUCTION

Medial unicompartmental knee arthroplasty (mUKA) is indicated for anteromedial osteoarthritis (AMOA) with medial full thickness cartilage loss (FTCL). Previous studies have reported controversial outcomes in patients with partial thickness cartilage loss (PTCL) who undergo mUKA. However, there is no reliable way to predict which PTCL patients do well. The aim of the present study was to investigate whether Kellgren-Lawrence (KL) grade is associated with clinical outcomes following mUKA patients with PTCL.

MATERIALS AND METHODS

Cartilage loss in the medial compartment was evaluated via MRI and intra-operatively according to the International Cartilage Repair Society (ICRS) classification system. Standing anteroposterior and lateral radiographs were taken to determine the KL grade. The patients, were grouped as having FTCL or PTCL with KL 0-2 and KL 3. The clinical data from the latest follow-up were assessed via the Forgotten Joint Score (FJS-12 score), the Oxford Knee Score (OKS), and the Knee Injury and Osteoarthritis Outcome Score (KOOS). Postoperative complications were also observed and recorded.

RESULTS

We studied 40 knees of 39 patients with PTCL and matched them with 40 knees with FTCL for mUKAs. The groups were similar in terms of age, sex, operative side, BMI and follow-up. The mean OKS (P = 0.014), KOOS pain (P = 0.040), KOOS symptom (P = 0.028), and KOOS sport (P = 0.034) scores were significantly lower in the PTCL group than in the FTCL group. To evaluate the effect of the KL grade, patients were categorized into the following groups: FTCL, PTCL with KL 0-2 and KL 3. The mean OKS (P = 0.044), KOOS symptom (P = 0.047) and KOOS sport (P = 0.045) scores were significantly lower in the PTCL with KL 0-2 group. However, no significant difference was found between the FTCL and PTCL with KL 3 in terms of the FJS-12, OKS and KOOS scores. No patients had any complications requiring reoperation or surgical revision.

CONCLUSIONS

PTCL patients who have KL 3 AMOA are not contraindicated by mUKA when nonoperative treatment for those patients have otherwise failed. However, PTCL patients with KL 0-2 AMOA are not equally suited for treatment with mUKA, and other treatment options should be considered.

Psychometric Validation of the Persian Version of the Lysholm Score

Background

The Lysholm Knee Score (LKS) is a widely utilized patient-reported outcome measure for knee injury patients, due to its robust psychometric properties. It has been translated and validated in several languages, but it has not been translated into Persian.

Purpose

To perform psychometric validation and cultural adaptation for the Persian version of the LKS (P-LKS) in patients with anterior cruciate ligament tears.

Study Design

Cohort study (diagnosis); Level of evidence, 3.

Method

The LKS was translated into Persian using a forward-backward translation procedure. To assess the reliability and validity of the P-LKS, responses were gathered from 100 consecutive patients (mean age, 35 ± 13 years; 91 male and 9 female). These participants also fulfilled the Persian versions of the International Knee Documentation Committee Subjective Form (IKDC-SF) and the 36-Item Short Form Health Survey (SF-36). Construct validity was evaluated by correlating the scores from the P-LKS with those from the Persian IKDC-SF and SF-36. Reliability was determined by examining test-retest reliability and internal consistency. Additionally, floor and ceiling effects, as well as measurement errors, were assessed. The Bland-Altman method was utilized to evaluate absolute agreement.

Results

Construct validity was strong, as >80% of the predetermined hypotheses regarding correlations between the P-LKS and other measures were verified. The P-LKS exhibited a high correlation with the Persian IKDC-SF (r = 0.92) and the physical component of the Persian SF-36 (r = 0.85). Bland-Altman analysis indicated no systematic bias among the test and retest phases. The test-retest reliability and internal consistency for the P-LKS were excellent (ICC = 0.97; Cronbach alpha = 0.88). Floor and ceiling effects for the overall score of the P-LKS were <15% (0% and 2%, respectively). The standard error of measurement was 1.04; the minimal detectable change at the individual level was 2.88, and at the group level, it was 0.29.

Conclusion

The study demonstrated that the P-LKS successfully preserved the attributes of the original version. It can be regarded as a reliable tool for Persian-speaking patients with complete anterior cruciate ligament tear.

Preoperative Psychopharmacological Treatment Is Not a Risk Factor for Poorer Patient-Reported Improvements 12 months After Hip or Knee Arthroplasty: A Multicenter Registry-Based Cohort Study of 7,247 Procedures

BACKGROUND

Preoperative psychopharmacological treatment (PPT) has been associated with increased hospital length of stay and readmission rate after hip and knee arthroplasty. However, little is known regarding the association between PPT and improvements in patient-reported outcomes postoperatively in a multicenter fast-track setting. Thus, the primary objective was to investigate whether PPT is a risk factor for poorer patient-reported improvements 12 months after surgery. Secondary objectives included assessment of additional time points and subgroups of PPT.

METHODS

This multicenter registry-based cohort study included 4,021 primary hip and 3,226 primary knee arthroplasties performed from 2016 to 2020 at three fast-track departments in Denmark due to primary osteoarthritis. The Oxford Hip Score/Oxford Knee Score (OHS/OKS), EuroQol-5 Dimensions-3 Levels/EuroQol-5 Dimensions-5 Levels, and EuroQol visual analog scale were collected at baseline and 3, 6, 12, and 24 months after surgery. Exposure status was assigned using the Danish National Prescription Registry. Marginal mean differences (MD) with 95% confidence intervals (CIs) were estimated using multilevel Tobit regression and adjusted for age, sex, and the Charlson Comorbidity Index obtained from the Danish National Patient Register.

RESULTS

No associations were found between PPT and improvements in OHS (MD -0.5, CI -1.4 to 0.4) or OKS (MD -0.3, CI -1.2 to 0.5) after 12 months. However, PPT was associated with lower baseline OHS (MD -1.4, CI -2.2 to -0.6) and OKS (MD -2.1, CI -2.9 to -1.3), and 12 months follow-up OHS (MD -1.9, CI -2.8 to -1.1) and OKS (MD -2.4, CI -3.2 to -1.6). Similar findings were observed at other time points, using EuroQol-5 Dimensions-3 Levels/EuroQol-5 Dimensions-5 Levels or EuroQol visual analog scale, and when evaluating PPT subgroups.

CONCLUSIONS

In hip and knee arthroplasty, PPT was not a risk factor for poorer patient-reported improvements 12 months after surgery. However, PPT was associated with marginally poorer baseline and follow-up scores. Thus, arthroplasties remain effective treatments despite PPT from a patient-centered perspective.

The incidence of radiolucent lines in cemented attune total knee arthroplasty- a retrospective clinical and radiological study

INTRODUCTION

The Attune total knee arthroplasty (TKA) system was introduced with the goal to improve clinical outcome, patient satisfaction and implant survival. The aim of the present study was to investigate the clinical and radiological outcome of the cemented Attune knee and to assess the rate of radiolucent lines (RLL) at a median follow-up of 4 years.

MATERIALS AND METHODS

In this single-center cohort study, we retrospectively evaluated the clinical and radiological results of 165 consecutive patients following cemented TKA with the original design of the Attune knee at a minimum follow-up of two years. Postoperative radiographs were assessed for RLL and clinical outcome was measured using patient reported outcome scores.

RESULTS

A total of 115 patients (127 knees) were available for assessment at a mean follow-up of 47.8 ± 12.9 months. The overall incidence of femoral and tibial RLL was 24% and 26%, respectively. Of the original cohort, two patients had to be revised during the course of the study, resulting in a survival rate of 98.9% at two years with the endpoint "revision for any reason". Clinical outcome scores improved significantly up to the latest follow-up.

CONCLUSIONS

The findings of this study demonstrated good clinical results with significant improvement in pain and knee function and acceptable revision rates at a median follow-up of 4 years. However, a high incidence of periprosthetic RLL was seen in this cohort. No implant showed signs of component loosening, but patients with RLL should be monitored closely and future studies with longer follow-up durations are necessary to investigate the influence of these radiolucencies on the long-term performance of this knee system.

Butyrate (short-chain fatty acid) alleviates lipopolysaccharide-binding proteins and improves physical function in knee osteoarthritis patients

Knee-osteoarthritis (OA) is often associated with increased intestinal permeability, potentially causing sarcopenia, and mobility issues. Current treatments are ineffective. The objective of this study was to investigate if butyrate improves sarcopenia and physical function in knee-OA patients, and if improvements correlate with changes in gut health, specifically intestinal permeability, and bacterial load. In this double-blind study, 60 OA patients received placebo, 52 received 300 mg butyrate daily for 12-weeks. Gut health (zonulin), and systemic bacterial load (lipopolysaccharide-binding proteins (LBP)) were assessed. Handgrip strength (HGS), Oxford knee scores (OKS), and short physical performance battery (SPPB) were measured at the beginning and end of the study to assess physical functionality. Patients taking butyrate showed improvement in HGS, walking speed, OKS scores, and maintained a better balance, walking ability and no decline in rising from chair, according to SPPB-scores. Butyrate lowered blood levels of zonulin, LBP, and CRP as markers of intestinal permeability, bacterial load, and inflammation, respectively (all p < 0.05). Regression analysis exhibited marked correlations of zonulin with HGS, OKS, walking speed, and SPPB scores in the butyrate-treated group. These observations suggest that butyrate could serve as a therapeutic option for sarcopenia and physical decline in OA, potentially by improving intestinal barrier function.

Evaluation of Functional Outcomes, Survivorship and Complications of Hypoallergenic Fixed-Bearing Medial and Lateral Unicompartmental Knee Arthroplasty: A Minimum 2-Year Follow-Up

Background: Unicompartmental knee arthroplasty (UKA) is a viable treatment option for patients with isolated knee osteoarthritis. This study evaluated the clinical outcomes of the JII UK (Smith & Nephew, Memphis, TN, USA) hypoallergenic, fixed-bearing UKA implant in a medium cohort of patients undergoing both medial and lateral procedures with a short-term follow-up. Methods: A retrospective review was conducted on 257 consecutive patients who underwent primary UKA using the JII UK implant between December 2020 and December 2022. Clinical outcomes were assessed using the Knee Society Score (KSS), Knee Society Function Score (KSFS), Oxford Knee Score (OKS), UCLA Activity Score, Forgotten Joint Score (FJS-12), and satisfaction. Survivorship analysis was performed, and complications were recorded. Results: At the 2-year follow-up, the implant survival rate was 99.61%. Statistical significant improvements were observed in all clinical scores, with high patient satisfaction. The mean UCLA Activity Score increased from 4.53 preoperatively to 7.3 at 24 months. Conclusions: This study demonstrates promising short-term clinical outcomes for the hypoallergenic fixed-bearing medial and lateral UKA implant, with high patient satisfaction and a low complication rate. Further studies with longer follow-up periods are warranted to confirm these findings.

Chronic pain at 1-year following knee arthroplasty is associated with a worse joint-specific function and health-related quality of life

PURPOSE

The purpose of this study was to identify independent variables associated with chronic pain (CP) at 1 year following knee arthroplasty (KA) and whether this influenced functional outcomes.

METHODS

This retrospective study was conducted over a 2-year period and included 2588 patients with completed Oxford knee score (OKS) and EuroQol (EQ)-five domains (5D) preoperatively and at 1 and 2 years postoperatively. The OKS pain component score was used to define patients with CP (≤14 points). The mean age was 70.0 (range 34-94) years and there were 1553 (60.0%) females.

RESULTS

There were 322 (12.4%) patients with CP at 1 year. A worse preoperative EQ-5D (p = 0.025), EQ-visual analogue scale (VAS) (p = 0.005) and OKS questions relating to washing (p = 0.010), limping (p = 0.007), kneeling (p = 0.003) and night pain (p = 0.004) were independently associated with risk of CP. However, the preoperative OKS (area under the curve [AUC]: 72.0, p < 0.001) and EQ-5D score (AUC: 70.1, p < 0.001) were the most reliable predictors, with threshold values of <18-points and <0.300 being predictive of CP, respectively. Of those with CP at 1 year, 231 were followed up at 2 years, of which 92 (39.8%) had resolution of their CP. A worse response to OKS question 11 (ability to shop) and EQ-5D (p = 0.028) at 1 year was independently associated with persistent CP. Patients with CP had significantly (p < 0.001) worse OKS, EQ-5D and EQ-VAS at 1 year compared to those without. However, for those that had resolution of their CP at 2 years, their outcomes were clinically equal to those that did not have CP at 1 year.

CONCLUSION

One in eight patients had CP at 1 year following surgery, which was associated with clinically worse knee-specific outcomes and quality of life. However, by 2 years, two in five patients had resolution of their CP and had functional outcomes clinically equal to those without CP at 1 year. The risk factors identified could be used to inform patients of their risk for CP and the potential for resolution.

LEVEL OF EVIDENCE

Level III retrospective study.

Does a medial congruent bearing in total knee arthroplasty compromise fixation? A randomized controlled trial

BACKGROUND

Medially congruent (MC) bearings aim at promoting medial pivoting after total knee arthroplasty (TKA), as the congruency provides further constraint for the medial femoral compartment. However, this design difference could alter intra-articular force distribution, potentially compromising fixation of the tibia implant. The aim of this study was to compare migration, measured with radiostereometric analysis (RSA), of an MC to a more traditional cruciate retaining (CR) TKA system. Secondary aims were to compare patient-perceived treatment outcome and number of complications between the treatment groups.

METHODS

Sixty patients undergoing TKA were randomized to an MC or CR bearing and had follow up visits after 3 months, 1 and 2 years. Primary outcome was tibia implant migration, measured by maximal total point motion (MTPM) with model-based RSA, 2 years post-surgery. Secondary outcomes were tibia MTPM, change in patient-reported outcome measurements (PROMs) and number of complications registered at all follow up visits.

RESULTS

Primary outcome was available for 52 patients (27 MC patients, 25 CR patients). We found no difference in tibia MTPM between the MC and CR groups 2 years post-surgery. Median (interquartile range) MTPM was 0.60 (0.39-0.97) mm and 0.48 (0.32-0.78) mm in the MC and CR group, respectively (P = 0.167). There were no between-group differences in improvement in PROMs and no between-group differences in number of complications.

CONCLUSION

We found no compromising of tibia implant fixation in TKA by choosing an MC bearing, when compared with a CR bearing. PROMs and complication rates suggest comparable treatment results with both types of bearings in TKA.

Patient-reported outcomes and complications of a new-generation total knee system: a randomized controlled trial

BACKGROUND AND PURPOSE

 Documentation of new-generation implants' short-term performance could reassure surgeons and patients about their use, while awaiting the long-term outcome. Our aim was to compare the performance of a newer total knee arthroplasty (TKA) system with its predecessor, measured by patient-reported knee function, pain, and complication rate.

METHODS

We performed a multi-center, randomized, controlled trial (clinicaltrials.gov ID: NCT03073941). 314 patients with primary osteoarthritis were randomized to treatment with a Persona or NexGen cruciate-retaining TKA system and followed for 2 years. The primary outcome was measured with the patient-reported outcome (PRO) Oxford Knee Score (OKS) 2 years post-surgery. Secondary outcomes were the OKS-Activity and Participation questionnaire (OKS-APQ), Forgotten Joint Score (FJS), EQ-5D-3L, and number of complications during the study period. Responder analyses were performed using Patient Acceptable Symptom State (PASS) and Minimal Important Change (MIC) criteria.

RESULTS

 Primary outcome was available from 289 patients (92%). We found no difference in adjusted mean OKS between the groups 2 years post-surgery (0.1, 95% confidence interval -1.4 to 1.7). We found no significant differences in adjusted mean of secondary PROs, PRO time-weighted averages, proportion of patients with PASS or MIC, or complications 2 years post-surgery.

CONCLUSION

 We found no difference in OKS 2 years post-surgery, or in any secondary variables analyzed including complications, between the 2 TKA systems. Short-term safety and performance of the Persona TKA was comparable to its predecessor.

The Effects of Computer Navigation and Patient-Specific Instrumentation on Risk of Revision, PROMs, and Mortality Following Primary TKR: An Analysis of National Joint Registry Data

BACKGROUND

Computer navigation and patient-specific instrumentation have been in use over the past 2 decades for total knee replacement (TKR). However, their effects on implant survival and patient-reported outcomes remain under debate. We aimed to investigate their influence on implant survival, outcomes of the Oxford Knee Score (OKS) and health-related quality of life (EQ-5D-3L), intraoperative complications, and postoperative mortality compared with conventional instrumentation, across a real-world population.

METHODS

This observational study used National Joint Registry (NJR) data and included adult patients who underwent primary TKR for osteoarthritis between April 1, 2003, and December 31, 2020. The primary analysis evaluated revision for all causes, and secondary analyses evaluated differences in the OKS and EQ-5D-3L at 6 months postoperatively, and mortality within 1 year postoperatively. Weights based on propensity scores were generated, accounting for several covariates. A Cox proportional hazards model was used to assess revision and mortality outcomes. Generalized linear models were used to evaluate differences in the OKS and EQ-5D-3L. Effective sample sizes were computed and represent the statistical power comparable with an unweighted sample.

RESULTS

Compared to conventional instrumentation, the hazard ratios (HRs) for all-cause revision following TKR performed using computer navigation and patient-specific instrumentation were 0.937 (95% confidence interval [CI], 0.860 to 1.021; p = 0.136; effective sample size [ESS] = 91,607) and 0.960 (95% CI, 0.735 to 1.252; p = 0.761; ESS = 13,297), respectively. No differences were observed in the OKS and EQ-5D-3L between conventional and computer-navigated TKR (OKS, -0.134 [95% CI, -0.331 to 0.063]; p = 0.183; ESS = 29,135; and EQ-5D-3L, 0.000 [95% CI, -0.005 to 0.005]; p = 0.929; ESS = 28,396) and between conventional TKR and TKR with patient-specific instrumentation (OKS, 0.363 [95% CI, -0.104 to 0.830]; p = 0.127; ESS = 4,412; and EQ-5D-3L, 0.004 [95% CI, -0.009 to 0.018]; p = 0.511; ESS = 4,285). Mortality within 1 year postoperatively was similar between conventional instrumentation and either computer navigation or patient-specific instrumentation (HR, 1.020 [95% CI, 0.989 to 1.052]; p = 0.212; ESS = 110,125).

CONCLUSIONS

On the basis of this large registry study, we conclude that computer navigation and patient-specific instrumentation have no statistically or clinically meaningful effect on the risk of revision, patient-reported outcomes, or mortality following primary TKR.

LEVEL OF EVIDENCE

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

Distal Femoral Replacement for Revision Total Knee Arthroplasty in Non-Oncologic Indications: A Single-Institution Outcomes Study

INTRODUCTION

Distal femoral replacement (DFR) is a salvage procedure to manage massive bone loss in total knee arthroplasty (TKA). Few studies report mid-term (five to 10 years) to long-term (>10 years) outcomes of DFR for non-oncologic indications. The purpose of this study was to report the implant survival of DFRs in non-oncologic TKA for the entire cohort and by indication, as well as patient-reported clinical outcomes.

METHODS

We retrospectively identified all DFR performed for non-oncologic indications from 2002 to 2021 at our institution. There were three patients who had less than a 2-year follow-up who were excluded (no revisions after DFR). There were 45 DFR included who had a mean follow-up of 6.6 years (range, 2.0 to 17.2). The mean age was 75 years (range, 53 to 94), the mean body mass index was 29.2 (range, 19.2 to 52.4), and 64.4% were women. Indications for index DFR were mechanical TKA failure (40.0%), periprosthetic fracture (33.3%), and periprosthetic joint infection (26.7%). There were fourteen (31.1%) patients who underwent revision after index DFR. Reasons for the first revision were infection (seven), fracture (three), hinge dislocation (two), loosening (one), and extensor mechanism rupture (one). All DFRs were rotating hinge designs with fully cemented stems. Kaplan-Meier analysis was used to determine all-cause revision-free Survival and patient-reported outcomes were collected.

RESULTS

The revision-free survival for the entire cohort was 74.6% at five years and 60.2% at 10 years. By indication for index DFR, six of the 12 infection patients, five of the 18 mechanical failure patients, and three of the 15 fracture patients underwent revision. Differences in revision-free survival by indication were not statistically different (P = 0.221). At the final follow-up, the mean Oxford knee score was 25 (range 5 to 40), with 69% patient satisfaction.

CONCLUSION

A DFR for non-oncological indications is associated with high revision rates. Mid-term (five to 10 years) and long-term (10 years) revision-free survival is poor, and patient satisfaction is modest. Differences in survival by indication for DFR were not statistically significant. DFR remains a valuable salvage procedure, but patients need to be counseled on the expected outcome.

Risk factors for valgus subsidence in uncemented medial unicompartimental knee arthroplasty

Aims

Valgus subsidence of uncemented tibial components following medial unicompartmental knee arthroplasty (UKA) poses a challenge in the early postoperative phase, necessitating a comprehensive understanding of its prevalence, risk factors, and impact on patient outcomes.

Methods

This prospective multicentre study analyzed 97 knees from 90 patients undergoing UKA across four participating hospitals. A standardized surgical technique was employed uniformly by all participating surgeons. Postoperative evaluations were conducted preoperatively, and one day, four weeks, three months, and one year postoperative, encompassing weightbearing radiographs, bone mineral density assessments, and clinical outcome reports using the Forgotten Joint Score and Oxford Knee Score. Statistical analyses, including non-parametric correlation analysis using the Kendall correlation coefficient and Mann-Whitney U test, were performed to explore associations between subsidence and various patient-related or radiological parameters.

Results

A total of eight patients showed more than 2° valgus subsidence (8.2%), higher than previously reported rates. There were significant correlations between subsidence and higher preoperative varus alignment of the tibia, larger adaptation of the preoperative varus to a postoperative neutral or valgus alignment, mediolateral undersizing of the tibial component, excessive lateral load of tibial component by more lateral position of femoral component relative to tibial component, a lower T-score, and female sex. Our study found no significant difference in pain scores between subsidence and non-subsidence groups at various postoperative milestones.

Conclusion

These findings corroborate earlier suggested risk factors based on biomechanical models. Further research might provide the opportunity to identify high-risk groups preoperatively and adapt treatment strategies for these patients.

Total versus robotic-assisted unicompartmental knee replacement (TRAKER) for medial compartment osteorthritis: a randomized controlled trial

Aims

Unicompartmental knee arthroplasty (UKA) is associated with an accelerated recovery, improved functional outcomes, and retention of anatomical knee kinematics when compared to manual total knee arthroplasty (mTKA). UKA is not universally employed by all surgeons as there is a higher revision risk when compared to mTKA. Robotic arm-assisted (ra) UKA enables the surgeon to position the prosthesis more accurately when compared to manual UKA, and is associated with improved functional outcomes and a lower early revision risk. Non-randomized data suggests that, when compared to mTKA, raUKA has a clinically meaningful greater functional benefit. This protocol describes a randomized controlled trial that aims to evaluate the clinical and cost-effectiveness of raUKA compared to mTKA for individuals with isolated medial compartment osteoarthritis (OA).

Methods

The total versus robotic-assisted unicompartmental knee arthroplasty (TRAKER) trial is a patient- and assessor-blinded, pragmatic parallel two-arm randomized superiority trial of adults undergoing elective primary knee arthroplasty for primary medial compartment OA at a single NHS hospital (ClinicalTrials.gov NCT05290818). Participants will be randomly allocated on a 1:2 basis to either raUKA or mTKA, respectively. The primary analysis will compare the Oxford Knee Score (OKS) six months after surgery. Secondary outcomes measured at three, six, and 12 months include the OKS, Forgotten Joint Score, patient expectations, EuroQol five-dimension questionnaire (EQ-5D), and EQ-visual analogue scale (EQ-VAS), patient satisfaction, range of motion, postoperative complications, need for further surgery, resource use, and financial costs. Cost-effectiveness will be measured over a ten-year time span. A total of 159 patients will be randomized (n = 53 raUKA vs n = 106 mTKA) to obtain 80% power to detect a five-point difference in OKS between the groups six months after surgery.

Conclusion

The trial findings will provide evidence about the clinical and cost-effectiveness of raUKA compared to mTKA in patients with isolated medial compartment OA. This will inform future National Institute for Health and Care Excellence guidelines on primary knee arthroplasty in the UK.

Preoperative peripheral nerve blocks are not independently associated with improved functional outcome, patient satisfaction, or risk of chronic pain at one year following knee arthroplasty

Aims

Control of acute pain following knee arthroplasty (KA) with a perioperative peripheral nerve block (PNB) may improve functional outcomes and reduce the risk of chronic postoperative knee pain (CPKP). The aims of this study were to assess whether a PNB influences patient-reported outcomes and risk of CPKP at one year following KA.

Methods

A retrospective study was conducted over a two-year period and included 3,338 patients who underwent KA, of whom 1,434 (43.0%) had a lower limb PNB. A total of 2,588 patients (77.6%) completed and returned their one-year follow-up questionnaire. The Oxford Knee Score (OKS) and pain component (OKS-PS), EuroQol five-dimension questionnaire (EQ-5D), and EQ-visual analogue scale (VAS) were collected preoperatively and at one year postoperatively. Patient satisfaction was also recorded at one year. The OKS-PS was used to define CPKP at one year.

Results

The PNB group were younger (mean difference (MD) 0.7 years, 95% CI 0.0 to 1.3; p = 0.039), had a worse OKS (MD 0.7, 95% CI 0.1 to 1.3; p = 0.027), and were more likely to have had a spinal anaesthesia relative to a general anaesthetic (odds ratio 4.2, 95% CI 3.23 to 5.45; p < 0.001). When adjusting for confounding factors, patients in the PNB group had a significantly reduced improvement in their OKS (MD -0.9, 95% CI -1.6 to -0.1; p = 0.022), which may not be clinically meaningful. There were no significant differences in the OKS-PS (p = 0.068), EQ-5D (p = 0.313), or EQ-VAS (0.855) between the groups when adjusting for confounding factors. When adjusting for confounding factors using binary regression analysis, there were no differences in patient satisfaction (p = 0.132) or in the risk of CPKP (p = 0.794) according to PNB group.

Conclusion

PNBs were independently associated with worse knee-specific outcomes, but whether these are clinically meaningful is not clear, as the difference was less than the minimal clinically important difference. Furthermore, PNBs were not independently associated with differences in health-related quality of life, patient satisfaction, or risk of CPKP.

Kinematic Alignment Does Not Result in Clinically Important Improvements After TKA Compared With Mechanical Alignment: A Meta-analysis of Randomized Trials

BACKGROUND

There is debate as to whether kinematic TKA or mechanical alignment TKA is superior. Recent systematic reviews have suggested that kinematically aligned TKAs may be the preferred option. However, the observed differences in alignment favoring kinematic alignment may not improve outcomes (performance or durability) in ways that patients can perceive, and likewise, statistical differences in outcome scores sometimes observed in clinical trials may be too small for patients to notice. Minimum clinically important differences (MCIDs) are changes that are deemed meaningful to the patient. A meta-analysis of randomized trials that frames results on this topic in terms of MCIDs may therefore be informative to surgeons and their patients.

QUESTIONS/PURPOSES

(1) Does kinematic alignment for TKA insertion improve patient-reported outcome measures (PROMs) by clinically important margins (for example, 5 points of 48 on the adjusted Oxford Knee Score [OKS] or 13.7 points of 100 on the Forgotten Joint Score [FJS]) compared with mechanical alignment? (2) Does kinematic alignment for TKA insertion improve ROM by a clinically important margin (defined as 3.8° to 6.4° in flexion) compared with mechanical alignment?

METHODS

A systematic review of Medline and Embase databases was performed from inception to January 29, 2023, the date of search. We identified RCTs comparing mechanical alignment TKA with kinematic alignment TKA. All English-language RCTs comparing PROMs data in kinematic versus mechanical alignment TKAs performed in patients 18 years or older were included. Studies that were not in English, involved overlapping reports of the same trial, and/or utilized nonrandomized controlled trial methodology were excluded. Conference abstracts or study protocols, pilot studies, and review articles were also excluded. Two reviewers screened abstracts, full-text, and extracted data and assessed included studies for risk of bias using the Cochrane Risk of Bias tool, version 2. Twelve randomized controlled trials (RCTs) were identified, which included 1033 patients with a mean age of 68 years (range 40 to 94) from eight countries who were undergoing primary TKA. Six studies were determined to be low risk of bias, with the remaining six studies were determined to be of moderate-to-high risk of bias. As a result, we would expect that the included studies might overestimate the benefit of the newer approach. Outcomes included ROM and PROMs. Where feasible, pooled analysis was completed. PROMs data were extracted from nine pooled studies, with a randomized n = 443 in the kinematic alignment group and n = 435 in the mechanical alignment group. ROM data were extracted from six pooled studies, with randomized n = 248 in the kinematic alignment group and n = 243 in the mechanical alignment group. PROMS were converted to common scales where possible. Multiple versions of the OKS exist; therefore, OKS scores were converted if needed to a 0 to 48 Oxford scale, in which higher scores represent better clinical outcomes. WOMAC scores were converted to OKS using previously reported techniques. The OKS and converted WOMAC scores were represented as "functional scores" in our data set because of their conversion. An MCID of 5 was utilized as previously documented for the OKS. Heterogeneity was assessed using the I2 statistic, and for an I2 of > 25%, random-effects models were utilized.

RESULTS

In nine pooled studies, we found no clinically important difference between the kinematic and mechanical alignment groups in terms of our generated functional score (mean difference 3 of possible 48 [95% confidence interval (CI) 0.81 to 4.54]; p = 0.005). The functional score included OKS and WOMAC scores converted to OKS. The difference did not exceed the MCID for the OKS. In three pooled studies, we found no difference between the kinematic and mechanical alignment groups in terms of FJS at 1 to 2 years (mean difference 4 of possible 200 [95% CI -1.77 to 9.08]; p = 0.19). In three pooled studies, we found no difference between the kinematic and mechanical alignment groups in terms of EuroQol 5-domain instrument VAS score at 1 to 2 years (mean difference 0.2 of possible 100 [95% CI -3.17 to 3.61]; p = 0.90). We found no clinically meaningful difference between kinematic TKA and mechanical alignment TKA for ROM (extension mean difference 0.1° [95% CI -1.08 to 1.34]; p = 0.83, and flexion mean difference 3° [95% CI 0.5 to 5.61]; p = 0.02).

CONCLUSION

This meta-analysis found no clinically important benefit favoring kinematic over mechanical alignment in TKA based on the available RCTs. Because patients cannot perceive advantages to kinematic alignment, and because it adds costs, time (if using advanced technologies), and potential risks to the patient that are associated with novelty, it should not be widely adopted in practice until or unless such advantages have been shown in well-designed RCTs.

LEVEL OF EVIDENCE

Level I, therapeutic study.

High Prevalence of Symptomatic Knee Osteoarthritis Among Patients Who Have Fragility Hip Fractures

BACKGROUND

Knee osteoarthritis (OA) is a common degenerative musculoskeletal condition that impairs mobility and balance, increasing fall risk. When combined with osteoporosis, it further increases the risk of fragility fractures. Despite its prevalence, the frequency of knee OA in patients who have fragility hip fractures (FHFs) is not well established. This study aimed to determine the prevalence of knee OA among FHF patients.

METHODS

We conducted a cross-sectional analysis of patients who underwent surgical treatment for FHF. The knee OA diagnoses followed the American College of Rheumatology criteria, and severity was assessed via the Kellgren-Lawrence classification system. Bone mineral density (BMD) was evaluated at the lumbar spine and contralateral hip, and fall risk was assessed using a self-report questionnaire.

RESULTS

Among the 162 patients who had FHF (mean age 79 ± 8.1 years; 80.2% women), 66% had symptomatic knee osteoarthritis (SKOA). Of these, 21.0% were classified as end-stage knee osteoarthritis. Notably, 47.1% of these end-stage knee osteoarthritides were recommended for knee OA surgery before their hip fracture. The presence of SKOA was significantly associated with a history of multiple falls (P = 0.013) and a high fall risk (P = 0.020). Among the 120 patients who had BMD data, 68% had low BMD (T-score ≤ -2.5) at the contralateral hip or lumbar spine. Almost half (45%) of the FHF patients had concurrent SKOA and low BMD, whereas approximately 20% had SKOA, low BMD, and a high fall risk.

CONCLUSIONS

There is a high prevalence of SKOA among FHF patients. Comprehensive evaluation and management of knee OA and osteoporosis are essential to reduce the risk of subsequent fractures in this vulnerable population.

Diabesity is associated with a worse joint specific functional outcome following primary total knee replacement

INTRODUCTION

The combined effect of diabetes mellitus and obesity (Diabesity) on total knee replacement (TKR) outcomes is unclear. This study aimed to assess whether diabesity influenced functional outcomes and complication rate following primary TKR.

MATERIALS AND METHODS

This case-controlled study compared the independent effects of obesity, diabetes, and diabesity on TKR outcomes. Data were collected pre-operatively and 12 months post-operatively from a single study centre. Outcomes included Oxford Knee Score (OKS), EuroQol 5-dimensions (Eq. 5D), post-operative satisfaction and complication rate.

RESULTS

There were 2577 TKRs in the cohort, of which 244 (9.5%) had diabesity. Diabesity was independently associated with reduced pre-operative OKS (-1.14 points, 95% CI -1.97 to -0.31, p = 0.007) and OKS improvement (-2.37 points, 95% CI -3.11 to -1.62, p < 0.001). Obesity was also independently associated with worse pre-operative OKS (-0.78 points, 95% CI -1.28 to -0.27, p = 0.003) and OKS improvement (-0.81 points, 95% CI -1.26 to -0.35, p = 0.001). Both diabesity (-0.05 points, 95% CI -0.08 to -0.02, p = 0.003) and obesity (-0.02 points, 95% CI -0.04 to 0.00, p = 0.039) were associated with worse pre-operative Eq. 5D score. Patients with diabesity reported reduced post-operative satisfaction due to obesity independently (OR 0.75, 95% CI 0.56 to 1.00, p = 0.048). Diabesity was not independently associated with post-operative complications.

CONCLUSIONS

Diabesity was independently associated with a worse knee-specific function and Eq. 5D score pre-operatively, and diminished joint specific functional improvement following TKR. Patients with diabesity also experienced reduced post-operative satisfaction due to obesity independently.

Are Current Patient-Reported Outcome Measures Fit for Purpose to Evaluate Unicompartmental Knee Arthroplasty?

The optimal procedure for isolated end-stage medial compartment knee osteoarthritis (OA) remains uncertain, with debate persisting between unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). The aim of this narrative review is to evaluate current outcome measures in knee arthroplasty (KA) and explore how evolving patient populations and technological advancements may necessitate the use of different patient-reported outcome measures (PROMs) for evaluating UKA. While UKA offers potential advantages over TKA in early pain relief and functional outcomes, most randomised control trials using traditional PROMs have failed to show definitive superiority. The recent introduction of robotic assistance may have further enhanced the benefits of UKA. However, it remains uncertain whether the advantages outweigh the higher revision rates associated with UKA. Although traditional PROMs, such as the Oxford Knee Score or Knee Injury and Osteoarthritis Outcome Score, were designed for the KA population of 30 years ago, they continue to be employed today. The current KA population, particularly those undergoing UKA, are typically younger, physically fitter, and have higher functional demands than those for whom traditional PROMs were originally designed. As a result, these PROMs are now limited by ceiling effects. High-performance PROMs, such as the Forgotten Joint Score-12 or the metabolic equivalent of task score, have recently been utilised for high-demand patients and do not have postoperative ceiling effects. Return to work and sport are also important outcomes that are often overlooked for younger, high-demand patients. Future studies should aim to define the differences between UKA and TKA populations, identify patient factors that predict UKA success, and validate high-performance PROMs for UKA. This will provide deeper insights into the functional benefits of UKA and TKA, enabling patients and surgeons to make more informed decisions regarding implant selection.

Outcomes following functionally aligned total knee arthroplasty in severe varus deformity

Introduction

Total knee arthroplasty (TKA) in severe varus deformity still remains a challenge. Alternative alignment TKA aims to improve outcomes and satisfaction. The purpose of this study is to report on the outcomes of a functionally aligned TKA in severe varus deformity.

Methods

This is a retrospective review of single surgeon series. 92 patients with a varus deformity of >15⁰ on varus stress underwent a functionally aligned, TKA (Stryker Triathlon, Mahwah, New Jersey, USA) between 2016 and 2022. A control group, matched for age, gender and body mass index (BMI) from the same period was also identified with mild varus deformity (<10⁰). Intra-operative robotic data collected included gap measurements, bone resection depths, alignment, and rate of soft tissue releases. Clinical outcome data was collected as part of the prospective registry which included patient reported outcome measures (Forgotten Joint Score 12, Oxford Knee Score and Knee Injury and Osteoarthritis Outcome Score Joint Replacement), pain Visual analogue score (VAS), patient satisfaction and range of motion. We reported a minimum follow-up of 12 months.

Results

Medial soft tissue release was performed in 7.6 % of patients in the severe varus group. No soft tissue release was required in the control group. 96.7 % of TKAs achieved coronal balance in extension within 1 mm in the severe varus group. The varus stressed Hip knee ankle angle (HKA) was corrected by 8.5⁰ (95 % CI -9.4 to -7.6, p < 0.001). Patients in both group achieved excellent clinical outcomes scores and satisfaction (Severe varus: 91.9 % vs control: 92.7 %) at the final follow-up.

Conclusion

Patient with severe varus deformity (>15⁰) undergoing a functionally aligned TKA achieve a well-balanced TKA with excellent clinical outcomes and small rates of soft tissue release.

Inferior short-term survivorship and patient outcomes for cementless compared to hybrid fixation with a cemented femoral implant in a novel blade-anchored medial unicompartmental knee arthroplasty design: An analysis of 132 cases

PURPOSE

For younger, more active patients, a cementless unicompartmental knee arthroplasty (UKA) might be more advantageous than cemented fixation. Therefore, this study aimed to compare implant survivorship and patient-reported outcome measures (PROMs) between cementless and hybrid fixation (cemented femur and cementless tibial fixation) in a novel tibial blade-anchored, medial UKA design.

METHODS

Two surgeon's registries were reviewed for patients who underwent primary cementless or hybrid medial UKA for medial osteoarthritis between 2019 and 2022. Patients were included if implant survivorship and one-year postoperative PROMs (UCLA-activity score, Oxford Knee Score (OKS), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR), pain (VAS) and satisfaction) were registered. Variables were compared using independent two-sample t-tests or the Chi-square test. Survival rates were determined using the Kaplan-Meier models and compared using the Log-rank test.

RESULTS

A total of 132 knees were included (cementless 58.3%; cemented 41.7%; mean follow-up 3.1 ± 0.6 years). Three-year all-cause revision survival rate was significantly superior for the hybrid fixation (hybrid: 100%; cementless 88.5%[84.7%-92.3%], p = 0.026). However, the difference in three-year conversion rate to total knee arthroplasty (TKA) did not reach statistical significance. The one-year postoperative OKS (hybrid: 42.9 ± 4.8; cementless: 39.8 ± 6.4, p = 0.003) and KOOS-JR (hybrid:81.5 ± 13.7; cementless: 74.4 ± 12.1, p = 0.002) were significantly superior for the hybrid fixation. Three-year conversion rate to TKA and two-year postoperative PROMs did not significantly differ.

CONCLUSION

The cementless medial UKA demonstrated a significantly inferior short-term all-cause survival rate and inferior postoperative one-year OKS and KOOS-JR compared to the hybrid medial UKA design with a cemented femoral component.

Obesity and hyperlipidemia were associated with more severe synovitis and structural abnormalities as well as inferior functional outcomes in knee osteoarthritis: a retrospective comparative study

BACKGROUND

Considering that the respective effects of obesity and hyperlipidemia on knee osteoarthritis (OA) have not been fully investigated, the purpose of this study was to determine the relationship of obesity or hyperlipidemia with the synovitis and structural abnormalities of knee OA, and the effect of obesity and hyperlipidemia on functional outcomes of total knee arthroplasty.

METHODS

There were 99 OA patients without obesity and hyperlipidemia in Group 1, 100 OA patients only with obesity in Group 2, 98 OA patients only with hyperlipidemia in Group 3, and 97 OA patients with both obesity and hyperlipidemia in Group 4. Semi-quantitative synovial inflammatory markers were measured including effusion-synovitis, size and intensity of infrapatellar fat pad abnormality, and synovial proliferation score. The structural abnormalities of knee OA were evaluated using Whole-Organ Magnetic Resonance Imaging Score (WORMS). Functional outcomes were evaluated before surgery and at 2 years follow-up.

RESULTS

There were significantly higher effusion-synovitis, size and intensity of infrapatellar fat pad abnormality, and synovial proliferation score, as well as higher cartilage, bone marrow edema, meniscus, and total WORMS scores in Group 2, Group 3, and Group 4 (P < 0.05), but with no significant difference between Group 2 and Group 3 (P > 0.05). Group 2, Group 3, Group 4 had significantly worse Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, Oxford Knee Score, Knee Society Score at baseline and 2 years follow-up (P < 0.05), but with no significant difference between Group 2 and Group 3 (P > 0.05). There were significant associations of obesity or hyperlipidemia with all synovial inflammatory markers and cartilage, bone marrow edema, meniscus, and total WORMS scores as well as functional outcomes (P < 0.05).

CONCLUSIONS

Obesity and hyperlipidemia were associated with more severe synovitis and structural abnormalities of knee OA, as well as inferior preoperative and postoperative functional outcomes. The negative effects of obesity and hyperlipidemia on knee OA could be mutually enhanced. The findings emphasized the negative effects of obesity and hyperlipidemia on the symptoms and outcomes of knee OA, and highlighted the association of obesity and hyperlipidemia with synovitis.

Different intraoperative joint laxity patterns do not impact clinical outcomes in robotic-assisted medial unicompartmental knee replacement with 1-to-1 surface reconstruction

PURPOSE

Robotic-assisted technology in medial unicompartmental knee arthroplasty (mUKA) allows for customized adjustments of joint laxity through virtual preoperative component positioning before bone preparation. Nevertheless, the optimal balancing curve has yet to be delineated. This study sought to investigate if varying intraoperative knee laxity patterns had any impact on postoperative patient outcomes.

MATERIALS AND METHODS

A retrospective analysis was conducted on prospectively collected data from 326 fixed-bearing RAUKA procedures performed between 2018 and 2022 with a minimum 2-year follow-up. Patients were categorized into three cohorts based on intraoperative joint laxity patterns (millimetres of joint gap during valgus stress) imparted at 20°, 60°, 90° and 120° of knee flexion: cohort 1 < +0.5 mm (tight); cohort 2 between 0.6 and 1.9 mm (physiologic); cohort 3 > 2 mm (loose). Wilcoxon and Kruskal-Wallis tests were conducted to assess patient-reported outcome measure (PROM) improvements and preoperative and postoperative differences across the cohorts. A Spearman's test evaluated the correlation between knee balance at all degrees of flexion and preoperative and postoperative HKA.

RESULTS

No differences in preoperative and postoperative PROMs were identified across the cohorts (p > 0.05). All three cohorts with different joint laxity patterns showed a significant improvement in the postoperative PROMS (p < 0.05). The preoperative or postoperative limb alignment did not significantly affect clinical outcomes relative to different laxity patterns.

CONCLUSION

No differences were found in the outcomes across different joint laxity patterns in robotic-assisted medial UKA using fixed-bearing mUKAs. There was no evident advantage for maintaining a closer to physiologic laxity compared to tighter or looser balancing.

LEVEL OF EVIDENCE

Level III, therapeutic study.

The in-vivo medial and lateral collateral elongation correlated with knee functional score and joint space following unicompartmental knee arthroplasty

BACKGROUND

The medial collateral ligament (MCL) and lateral collateral ligament (LCL) are paramount for joint stability. Their elongation patterns may change during fixed-bearing and mobile-bearing unicompartmental knee arthroplasty (FB and MB UKA). This study aims to explore the relationship between the elongation of MCL, LCL, and changes in joint space, as well as their correlation with functional scale scores during FB and MB UKA.

HYPOTHESIS

We hypothesize that MCL and LCL have different elongation patterns in UKA patients, and there is a correlation between elongation and joint space and functional scores.

MATERIALS AND METHODS

The study recruited 24 patients undergoing UKA on a unilateral knee (13 FB and 11 MB). A dual fluoroscopic imaging system was employed to assess in-vivo knee kinematics during static standing and single-leg lunge. The superficial and deep MCL (sMCL, dMCL) and LCL were divided into anterior, medium, and posterior portions. The virtual ligament method quantified in-vivo ligament lengths. Analysis focused on the correlation of normalized ligament lengths with functional scores and joint space.

RESULTS

1. LCL Elongation in FB UKA: There is a significant increase in LCL elongation during early and mid-flexion of the single-leg lunge (p < 0.05). 2. MCL Elongation in MB UKA: Both sMCL and dMCL exhibit significant elongation during early and mid-flexion of the single-leg lunge (p < 0.05). 3. Correlation with Functional Scores: Differences in collateral ligament elongation in FB UKA are significantly correlated with the OKS and KSS, highlighting the impact on functional outcomes. In MB UKA, differences in ligament elongation are significantly correlated with the FJS. 4. Joint Space Correlation: There is a significant correlation between the elongation of the anterior and medium portions of dMCL and joint space in the surgical compartment during mid- and deep flexion (30-100°, p < 0.05, r > 0.64).

CONCLUSION

The study reveals distinct ligament elongation patterns between UKA and native knees in LCL for FB UKA and MCL for MB UKA. These patterns are associated with knee functional scores. Moreover, dMCL elongation correlates significantly with the joint space for MB UKA during middle and deep flexion phases.

LEVEL OF EVIDENCE

III; prospective retrospective cohort study.

Responsiveness and minimal clinically important changes of common patient-reported and performance-based outcome measures of physical function in patients with knee osteoarthritis

PURPOSE

We investigate and compare responsiveness of the physical function subscales of patient-reported measures of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) and Oxford Knee Score (OKS), and performance-based measures of the timed up-and-go test and 6-min walk test and determine the minimal clinically important change (MCIC) values in knee osteoarthritis (OA) patients following physiotherapy intervention.

METHODS

One hundred patients were asked to complete the WOMAC and OKS and to perform the timed up-and-go test and 6-min walk test once pre-intervention and again after 4-week physiotherapy intervention (post-intervention). Responsiveness was determined by correlation analysis and receiver operating characteristics (ROC) curve.

RESULTS

The WOMAC-physical function subscale (WOMAC-PF), OKS-functional component score (OKS-FCS), timed up-and-go test, and 6-min walk test showed moderate-to-good relationships with the patients' global rating scale (Spearman correlation ranges = 0.51-0.56). All outcome measures of physical function showed the area under the curve (AUC) >0.70 (AUC ranges = 0.78-0.82). The MCIC values were 12.5 points for WOMAC-PF, 17.5 points for OKS-FCS, 2.82 s for timed up-and-go test, 61 m for 6-min walk test.

CONCLUSIONS

All outcome measures have adequate responsiveness to detect clinical improvements over time in functional status following the physiotherapy intervention in patients with knee OA. The MCIC values can help clinicians and researchers to make a decision based on the clinical significance of improvements in patients' functional status.

Comparison of Patients Based on Their Self-Selected Discharge Pathway after Total Knee Arthroplasty at an Ambulatory Surgical Center

Outpatient total knee arthroplasty (TKA) is being performed more frequently in ambulatory surgical centers (ASCs) to decrease the cost of care. Discharge pathways include 23-hour observation (OBSERVATION) or same-day discharge home (HOME), which differ in postoperative medical supervision. Few studies allow patients to self-select their discharge pathway. This study compared patient variables between self-selected OBSERVATION or HOME discharge after TKA at an ASC. We hypothesized that age, sex, and distance lived from the ASC would differ between discharge pathways. Clinical and patient-reported outcomes were explored.A chart review identified 130 patients with TKA at an ASC between November 2017 and December 2019. Patients self-selected OBSERVATION or HOME during a preoperative physician visit. Patient variables obtained from the electronic medical record were age, sex, race/ethnicity, marital status, body mass index, diabetic status, American Society of Anesthesiologists (ASA) class, distance lived from the ASC, anesthesia type, procedure time, and time in the postanesthesia recovery unit. Clinical outcomes (knee range of motion, infection rate, and reoperation rate) and patient-reported outcomes (Knee Injury and Osteoarthritis Outcome Score, Joint Replacement [KOOS, JR]; Oxford Knee Score [OKS]) were collected at either 6 or 12 weeks postsurgery. Variables were compared between groups.Pathway selection was n = 70 OBSERVATION and n = 60 HOME, and all patients completed their self-selected discharge pathway. Age and proportion of females were significantly higher in OBSERVATION than in HOME (61.3 ± 3.5 vs. 58.5 ± 5.4 years, 85.7 vs. 65.0%, respectively; p < 0.05). Distance lived from the ASC tended to be greater in OBSERVATION than HOME (22.1 ± 24.6 vs. 15.3 ± 10.1 miles, p = 0.056). Across groups, clinical outcomes were favorable (i.e., >88% met the 6-week knee flexion milestone, 1.9% infection rate, and 3.1% manipulation under anesthesia), and the preoperative to 12-week postoperative change in KOOS, JR and OKS scores met the minimal clinically important difference.Older age, female sex, and farther distance lived from the ASC may influence patients to select OBSERVATION over HOME discharge following TKA at an ASC. No robust differences were found in early outcomes.

New evidence on patella resurfacing in modern total knee arthroplasty for all inflammatory arthritis in a mixed Asian population

Background

Traditional teaching advocates for routine patella resurfacing (PR) during total knee arthroplasty (TKA) in patients with inflammatory arthritis. However, evidence on this topic remains limited in the Asian population. This study aims to evaluate the postoperative outcomes and complication of patella resurfacing (PR) during primary total knee arthroplasty (TKA) in Asian patients with inflammatory arthritis.

Methods

A retrospective analysis was conducted using registry data from our institution. Patients with inflammatory arthritis who underwent primary TKA from August 2017 to December 2021 were included in the study. Patients were divided into two groups - patella resurfaced (PR, n = 25) and non-resurfaced patella (PNR, n = 31) groups. Demographics, operative data, patient reported outcome measures, and complications were compared.

Results

Preoperative range of motion (ROM) (PR:95.3 ± 23.6° vs PNR:105 ± 19.5°, p = 0.106), Knee Society Scoring System Knee score (KS-KS) (PR:44.6 ± 17.4 vs PNR:49.3 ± 17.7, p = 0.331) and Knee Society Function Score (KS-FS) (PR:40.9 ± 27.3 vs PNR:47.7 ± 27.0, p = 0.325) and Oxford Knee Score (OKS) (PR:25.0 ± 7.8 vs PNR:23.3 ± 10.3, p = 0.525) were similar in both groups. Outcomes between PR and PNR groups at the one-year mark in terms of ROM (PR:112.7 ± 18.1 vs PNR:114.6 ± 16.5, p = 0.455), OKS (PR:41.5 ± 3.9 vs PNR:41 ± 4.7, p = 0.954), KS-KS (PR:84.5 ± 13.2 vs PNR:89.2 ± 9.3, p = 0.095) and KS-FS (PR:73.6 ± 18.3 vs PNR:78.7 ± 19.3, p = 0.173) were also similar. Intraoperative complication (PR:0/25 vs PNR: 3/31 (9.6 %), p = 0.245) and re-operation rates (PR: 1/25 (4 %) vs PNR: 1/31 (3.2 %), p = 0.877) were also similar in both groups.

Conclusion

This study conducted on a mixed Asian population with inflammatory arthritis demonstrated that the one-year postoperative ROM and functional outcomes, complication, and re-operation rates between PR and PNR groups were similar. Hence, routine patella resurfacing on all Asian patients with inflammatory arthritis undergoing TKA may not be necessary.

Item response theory validation of the Oxford knee score and Activity and Participation Questionnaire: a step toward a common metric

OBJECTIVES

The Oxford knee score (OKS) and OKS Activity and Participation Questionnaire (OKS-APQ) are patient-reported outcome measures used to assess people undergoing knee replacement surgery. They have not explicitly been tested for unidimensionality (whether they measure one underlying trait such as 'knee health'). This study applied item response theory (IRT) to improve the validity of the instruments to optimize for ongoing use.

STUDY DESIGN AND SETTING

Participants undergoing primary total knee replacement (TKR) provided preoperative and postoperative responses for OKS and OKS-APQ. Confirmatory factor analysis (CFA) were performed on the OKS and OKS-APQ separately and then on both when pooled into one. An IRT model was fitted to the data.

RESULTS

2972 individual response patterns were analyzed. CFA demonstrated that when combining OKS and OKS-APQ as one instrument, they measure one latent health trait. A user-friendly, free-to-use, web app has been developed to allow clinicians to upload raw data and instantly receive IRT scores.

CONCLUSIONS

The OKS and OKS-APQ can be combined to use effectively as a single instrument (producing a single score). For the separate OKS and OKS-APQ the original items and response options can continue to be posed to patients, and this study has confirmed the suitability of IRT-weighted scoring. Applying IRT to existing responses converts traditional sum scores into continuous measurements with greater granularity, including individual measurement error.

Reliability of the Star Excursion Balance Test with End-Stage Knee Osteoarthritis Patients and Its Responsiveness Following Total Knee Arthroplasty

Background/Objectives: The Star Excursion Balance Test (SEBT) is a simple and feasible tool for assessing dynamic balance in individuals with knee osteoarthritis (KOA). It has an advantage as it replicates dynamic balance better than other static balance tools. This study aims to determine how reliable SEBT is among people with end-stage KOA, as well as how responsive it is and how well it correlates with performance-based outcome measures after TKA. Methods: Patients on the waiting list for TKA performed SEBT in the anterior, posteromedial and posteriorlateral directions twice within 7 days. The measurements were repeated 6 and 12 months after TKA. The participants completed performance-based outcome measurements (PBOMs) and the Oxford Knee Score (OKS) before and after TKA to estimate correlation. Results: In all directions, the intraclass correlation coefficient range (ICC) was 0.998-0.993, and there were no significant differences between the test and re-test mean SEBT scores. The standard error of measurement (SEM) ranged from 0.37% to 0.68%, and the minimum detectable change (MDC) ranged from 1.02% to 1.89%. The post TKA SEBT results show significant improvement, with a large effect size. There were large-to-medium correlations between SEBT and PBOMs before and after TKA, while OKS correlated only before surgery. The magnitude of change in SEBT, PBOMs and OKS did not correlate. Conclusions: SEBT is an extremely reliable tool for assessing dynamic balance in all three directions of severe KOA patients. It is sensitive enough to detect balance changes at 6 and 12 months post TKA. SEBT cannot be used to reflect the change in functional outcome improvement after TKA.

Implant design influences the joint-specific outcome after total knee arthroplasty

Aims

The aims were to assess whether joint-specific outcome after total knee arthroplasty (TKA) was influenced by implant design over a 12-year follow-up period, and whether patient-related factors were associated with loss to follow-up and mortality risk.

Methods

Long-term follow-up of a randomized controlled trial was undertaken. A total of 212 patients were allocated a Triathlon or a Kinemax TKA. Patients were assessed preoperatively, and one, three, eight, and 12 years postoperatively using the Oxford Knee Score (OKS). Reasons for patient lost to follow-up, mortality, and revision were recorded.

Results

A total of 94 patients completed 12-year functional follow-up (62 females, mean age 66 years (43 to 82) at index surgery). There was a clinically significantly greater improvement in the OKS at one year (mean difference (MD) 3.0 (95% CI 0.4 to 5.7); p = 0.027) and three years (MD 4.7 (95% CI 1.9 to 7.5); p = 0.001) for the Triathlon group, but no differences were observed at eight (p = 0.331) or 12 years' (p = 0.181) follow-up. When assessing the OKS in the patients surviving to 12 years, the Triathlon group had a clinically significantly greater improvement in the OKS (marginal mean 3.8 (95% CI 0.2 to 7.4); p = 0.040). Loss to functional follow-up (53%, n = 109/204) was independently associated with older age (p = 0.001). Patient mortality was the major reason (56.4%, n = 62/110) for loss to follow-up. Older age (p < 0.001) and worse preoperative OKS (p = 0.043) were independently associated with increased mortality risk. An age at time of surgery of ≥ 72 years was 75% sensitive and 74% specific for predicting mortality with an area under the curve of 78.1% (95% CI 70.9 to 85.3; p < 0.001).

Conclusion

The Triathlon TKA was associated with clinically meaningful greater improvement in knee-specific outcome when compared to the Kinemax TKA. Loss to follow-up at 12 years was a limitation, and studies planning longer-term functional assessment could limit their cohort to patients aged under 72 years.

Mid-term outcomes of medial metal backed and all-polyethylene unicompartmental knee arthroplasty in obese patients: a retrospective propensity-matched analysis

BACKGROUND

This retrospective study compares the outcomes of unicompartmental medial fixed-bearing knee arthroplasty (mUKA), involving a cemented metal-backed (MB) or an all-polyethylene (AP) tibial component, performed in obese patients with a body mass index (BMI) > 30 with a follow-up of at least 5 years.

METHODS

The institutional database was mined for primary mUKAs involving an MB or an AP tibial component (MB-UKA and AP-UKA groups, respectively) performed from January 2015 to August 2019. Patient demographics and patient-reported outcome measures (PROMs) were compared and a propensity score matching (PSM) analysis (1:1) using multiple variables was conducted.

RESULTS

PSM analysis yielded 37 pairs of obese MB-UKA and AP-UKA patients. At 5 years, the Knee Society Function Score (KSFS) was 75.1 ± 10.6 in MB-UKA and 79.4 ± 9.1 in AP-UKA patients (p = 0.029), and the Oxford Knee Score (OKS) was 38.1 ± 4.4 in MB-UKA and 40.6 ± 5.7 in AP-UKA patients (p = 0.011).

CONCLUSION

At five-year follow-up, in a matched group of obese MB-UKA and AP-UKA patients, the AP-UKA group achieved better KSFSs and OKSs. Both the AP and the MB tibial components were able to bring about a significant improvement of the most widely used PROMs.

Impact of motivational feedback on levels of physical activity and quality of life by activity monitoring following knee arthroplasty surgery-protocol for a randomized controlled trial nested in a prospective cohort (Knee-Activity)

BACKGROUND

Evidence on how to improve daily physical activity (PA) levels following total knee arthroplasty (TKA) or medial uni-compartmental knee arthroplasty (mUKA) by motivational feedback is lacking. Moreover, it is unknown whether a focus on increased PA after discharge from the hospital improves rehabilitation, physical function, and quality of life. The aim of this randomized controlled trial (RCT) nested in a prospective cohort is (a) to investigate whether PA, physical function, and quality of life following knee replacement can be increased using an activity monitoring device including motivational feedback via a patient app in comparison with activity monitoring without feedback (care-as-usual), and (b) to investigate the potential predictive value of PA level prior to knee replacement for the length of stay, return to work, and quality of life.

METHODS

The study is designed as a multicenter, parallel-group, superiority RCT with balanced randomization (1:1) and blinded outcome assessments. One hundred and fifty patients scheduled for knee replacement (TKA or mUKA) will be recruited through Odense University Hospital, Denmark, Vejle Hospital, Denmark and Herlev/Gentofte Sygehus, Denmark. Patients will be randomized to either 12 weeks of activity monitoring and motivational feedback via a patient app by gamification or 'care-as-usual,' including activity monitoring without motivational feedback. The primary outcome is the between-group change score from baseline to 12-week follow-up of cumulative daily accelerometer counts, which is a valid proxy for average objectively assessed daily PA.

DISCUSSION

Improving PA through motivational feedback following knee replacement surgery might improve post-surgical function, health-related quality of life, and participation in everyday life.

TRIAL REGISTRATION

ClinicalTrials.gov, ID: NCT06005623. Registered on 2023-08-22.

TRIAL STATUS

Recruiting.

Determination of the effect of preoperative knee joint function on postoperative quality of life in patients with total knee arthroplasty

Primary total knee arthroplasty (TKA) is one of the most successful procedures for end-stage knee osteoarthritis. To determine the effect of preoperative knee joint function on postoperative quality of life in patients undergoing primary TKA. This descriptive cross-sectional study was conducted with a total of 208 patients in the orthopedics and traumatology clinic. Data were gathered with a personal information form, the Oxford Knee Score (OKS), and the EQ-5D-5L Quality Of Life Scale in the preoperative period, at postoperative 6th week, and at postoperative 3rd month. The data were analyzed using descriptive statistics, one-way analysis of variance (ANOVA), correlation analysis, and simple linear regression analysis. The mean age of the patients was 65.65 ± 7.01 years. Most patients (86.1%) were women, and 51.4% underwent left TKA. OKS scores indicated poor knee function preoperatively and gradually increased at postoperative 6th week and 3rd month. Preoperative OKS was a significant predictor of postoperative knee joint function and quality of life. This study shows that preoperative knee joint function significantly affects postoperative knee joint function and quality of life. These results demonstrate the importance of the surgery timing and suggest that performing surgery earlier in functional decline may be associated with a better outcome.

Inadequate Classification of Poor Response After Total Knee Arthroplasty: A Comparative Analysis of 15 Definitions Using Data From the Dutch Arthroplasty Register and the Osteoarthritis Initiative Database

BACKGROUND

Variations in defining poor response to total knee arthroplasty (TKA) impede comparisons of response after TKA over time and across hospitals. This study aimed to compare the prevalence, overlap, and discriminative accuracy of 15 definitions of poor response after TKA using 2 databases.

METHODS

Data of patients one year after primary TKA from the Dutch Arthroplasty Register (n = 12,275) and the Osteoarthritis Initiative database (n = 204) were used to examine the prevalence, overlap (estimated by Cohen's kappa), and discriminative accuracy (sensitivity, specificity, positive predictive value, negative predictive value, and Youden index) of 15 different definitions of poor response after TKA. In the absence of a gold standard for measuring poor response to TKA, the numeric rating scale satisfaction (≤ 6 'poor responder') and the global assessment of knee impact (dichotomized: ≥ 4 'poor responder') were used as anchors for assessing discriminative accuracy for the Dutch Arthroplasty Register and Osteoarthritis Initiative dataset, respectively. These anchors were chosen based on a prior qualitative study that identified (dis)satisfaction as a central theme of poor responses to TKA by patients and knee specialists.

RESULTS

The median (25th to 75th percentile) prevalence of poor responders in the examined definitions was 18.5% (14.0 to 25.5%), and the median Cohen's kappa for the overlap between pairs of definitions was 0.41 (0.32 to 0.59). Median (25th to 75th percentile) sensitivity was 0.45 (0.39 to 0.54), specificity was 0.86 (0.82 to 0.94), positive predictive value was 0.45 (0.34 to 0.62), negative predictive value was 0.89 (0.87 to 0.89), and the Youden index was 0.36 (0.20 to 0.43).

CONCLUSIONS

This study found a lack of overlap between different definitions of poor response to TKA. None of the examined definitions adequately classified poor responders to TKA. In contrast, the absence of a poor response could be classified with confidence.

Open Reduction and Orthogonal Tension Band Plating of an Isolated Periprosthetic Tibial Tubercle Fracture: A Case Report

CASE

A 67-year-old woman sustained a periprosthetic tibial tubercle avulsion fracture with extensor mechanism disruption. She underwent open reduction internal fixation (ORIF) with orthogonal mini-fragment plates applied in a tension band fashion with patellar tendon suture augmentation. Radiographs, range of motion, and patient-reported outcomes were completed over 1 year.

CONCLUSION

Isolated periprosthetic tibial tubercle fractures with disruption of the extensor mechanism can be treated with ORIF using orthogonal tension band plating. At 1-year follow-up, the surgical technique described in this report yielded radiographic union, clinical restoration of preinjury motion, and excellent patient-reported outcomes.

In the medium term, more than half of males report kinesiophobia after anterior cruciate ligament reconstruction

OBJECTIVES

Anterior cruciate ligament rupture is a serious trauma with long-term consequences for the patient. Psychological and physiological factors may negatively affect patient recovery after anterior cruciate ligament reconstruction (ACLR), and development of kinesiophobia is possible. The aim of this study was to examine the presence of kinesiophobia and lower-leg muscle strength recovery in both sexes after ACLR.

METHODS

140 ACLR patients agreed to participate in the study. Kinesiophobia was assessed using the Tampa Scale of Kinesiophobia (TSK). The Knee injury and Osteoarthritis Outcome Score (KOOS), Oxford Knee Score (OKS) and Tegner Activity Scale (TAS) were used for patient-related outcome measurements. In both legs quadriceps and hamstring muscle strength at 60°/s and 180°/s were measured with an isokinetic dynamometer. For dynamic balance and leg function, the Y-balance test and single-leg hop test were used.

RESULTS

100 (71%) males and 40 (29%) females-mean age 32.5 (±8.3)-were examined 5.5 (±1.25) years after ACLR. 68/140 patients (48.6%) reported a TSK kinesiophobia score equal to or higher than 37 points: 54/100 (54%) males and 14/40 (35%) females (p ​= ​0.04). Patients with kinesiophobia had significantly lower KOOS values (p ​< ​0.001). In terms of the TAS no significant differences were found between those with or without kinesiophobia. Knee strength deficiency at 180°/sec and 60°/sec was significantly higher in the kinesiophobia group in knee extension in males (p ​= ​0.009) and knee flexion in females (p ​= ​0.001). Normalized body weight isokinetic average peak torque strength tests were significantly better in males compared to females in both groups (p ​< ​0.001).

CONCLUSION

Both sexes reported high rates of kinesiophobia, but males are at higher risk of developing kinesiophobia than females in the medium term after ACLR. Furthermore, patients with kinesiophobia have significantly lower total KOOS scores, and females were significantly weaker than males in knee flexion and extension according to normalized body weight muscle strength tests. Also, a longer time from injury to surgery increases the risk of kinesiophobia in females.

LEVEL OF EVIDENCE

Level IV.

TYPE OF STUDY

Retrospective case series study.

CLINICAL TRIAL REGISTRATION

Trial registration in ClinicalTrials.gov. Identifier: NCT05762809.

Altered dynamic joint space in the lateral condyle compartment following medial unicompartmental knee arthroplasty

PURPOSE

The progression of osteoarthritis in lateral compartment has been identified as a primary complication in medial unicompartmental knee arthroplasty (UKA) revisions, irrespective of whether employing fixed bearing (FB) or mobile bearing (MB) designs. Compared to the previous contact point analyses, the tibiofemoral contacts during knee movements are comprehended by a more comprehensive understanding of joint spaces. This study aims to dynamically map the joint spaces in the lateral compartment during the single-leg lunge following FB and MB UKA procedures, and compare them with the respective contralateral native knees. It is hypothesized that the significant change in joint space for post-UKA compared to their native knees.

METHODS

Twelve patients with unilateral medial FB UKA and eleven patients with unilateral medial MB UKA were included and underwent computed tomography scans. The exclusion criteria included anterior cruciate ligament deficiency, postoperative knee pain, any postoperative complications, and musculoskeletal illnesses. A dual fluoroscopic imaging system was utilized to capture the single-leg lunge, and 2D-to-3D registration facilitated the visualization of knee motion. According to the knee motions, joint spaces on tibial and femoral surfaces in the lateral compartments of native, FB, and MB UKA knees were calculated and mapped.

RESULTS

In comparison to the native knees, FB UKA knees exhibited significant increases in medial, lateral, central, and posterior joint spaces in the lateral compartment (p < 0.05), while MB UKA knees showed significant increases only in central and posterior joint spaces (p < 0.05). Moreover, FB UKA demonstrated greater increases in medial, central, and posterior joint spaces compared to MB UKA. Tibial varus and valgus during lunges, as well as the Oxford Knee Score (OKS) and Hip-Knee-Ankle angle (HKA), correlated with joint spaces.

CONCLUSIONS

Dynamic joint space analysis provided a more comprehensive insight into contact dynamics. FB UKA led to an enlargement of joint spaces, whereas MB UKA resulted in joint spaces closer to native knees. These findings contribute to understanding potential postoperative complication in UKAs.

Genicular Nerve Block for Knee Osteoarthritis: A Systematic Review and Meta-analysis of Randomized Clinical Trials

OBJECTIVES

Genicular nerve block (GNB) has emerged as a novel nonsurgical therapy for symptomatic knee osteoarthritis (KOA). The objective was to evaluate GNB versus placebo and other intra-articular (IA) therapies.

METHODS

The Medline, Embase, and Scopus databases were searched from their inception to January 2021. Only randomized controlled trials (RCTs) were included. A random-effects model and the generic inverse variance method were used for quantitative data synthesis. Heterogeneity was tested with the I2 index.

RESULTS

Regarding pain statistically significant scores were demonstrated at 1 and 3 months overall total effect of 1.43 (95% CI, 0.86, 1.99; P= 0.00001; I2 =85%). Similarly, for knee function a total effect of 0.71 (95% CI, 0.35, 1.06; P= 0.00001; I2 =69%) at 1 and 3 months, statistically significant. The minimal clinically important difference regarding pain was achieved at 1 and 3 months.

DISCUSSION

Although, GNB achieved the MCID for KOA pain and statistically significant results for knee functions. We cannot recommend its routine use besides being a safe procedure so far, evidence is fair on GNB for primary KOA due to study heterogeneity and limited follow-up.

Long-term Outcomes after Medial Open Wedge High Tibial Osteotomy - A Retrospective Study of 69 Patients

High tibial osteotomy (HTO) is a widespread option to avoid or delay total knee arthroplasty (TKA). The present study aimed to assess the long-term survival rate and postoperative subjective knee function after isolated medial open wedge HTO in patients with symptomatic medial compartment knee osteoarthritis (OA) and varus malalignment.Sixty-nine patients (48.8 ± 6.7, 35-66 years; preoperative mechanical tibiofemoral angle [mTFA] -5.3 ± 3.4; -14.9-0.0° varus) treated with medial open wedge HTO using a TomoFix plate were included in this retrospective study, with a follow-up of at least 10 years (11.8 ± 1.0 years). The survival rate after HTO was calculated after 5 and 10 years. Subjective knee function was assessed using Hospital for Special Surgery (HSS), Oxford knee, Lequesne, and Lysholm scores.Thirty-three patients underwent conversion to TKA, on average, 7.0 ± 3.4 (1.3-13.7) years after HTO. Five- and ten-year survival rates were 84.1 and 60.9%, respectively. Patients without conversion to TKA showed a Lysholm score of 64.5 (35-92), Lequesne score of 7 (1-13), HSS score of 71 (56-86), and Oxford knee score of 38.5 (25-44) at the last follow-up (more than 10 years). Significantly higher scores were registered at the last follow-up compared to the preoperative state regarding the Lysholm score (preoperative: 43.5 [12-95]; follow-up: 64.5 [35-92]; p < 0.001). The HSS score (preoperative: 69.5 [43-93]; follow-up: 71 [56-86]; p = 0.6941) showed no statistically significant change during the 10-year follow-up period. The Lequesne score was significantly lower than the preoperative score (preoperative: 11.5 [0.5-22]; follow-up: 7 [1-13]; p < 0.001), indicating a lower handicap.The majority of patients with a valgus medial compartmental knee OA treated with HTO with fixation using the TomoFix plate can expect no conversion to TKA for more than 10 years. Furthermore, patients without conversion to TKA after 10 years still had a significantly higher subjective knee function than preoperatively. Further research is needed to identify risk factors for conversion to TKA. This helps to guide surgeons in selecting patients who will benefit most from HTO.

Identifying who are unlikely to benefit from total knee arthroplasty using machine learning models

Identifying and preventing patients who are not likely to benefit long-term from total knee arthroplasty (TKA) would decrease healthcare expenditure significantly. We trained machine learning (ML) models (image-only, clinical-data only, and multimodal) among 5720 knee OA patients to predict postoperative dissatisfaction at 2 years. Dissatisfaction was defined as not achieving a minimal clinically important difference in postoperative Knee Society knee and function scores (KSS), Short Form-36 Health Survey [SF-36, divided into a physical component score (PCS) and mental component score (MCS)], and Oxford Knee Score (OKS). Compared to image-only models, both clinical-data only and multimodal models achieved superior performance at predicting dissatisfaction measured by AUC, clinical-data only model: KSS 0.888 (0.866-0.909), SF-PCS 0.836 (0.812-0.860), SF-MCS 0.833 (0.812-0.854), and OKS 0.806 (0.753-0.859); multimodal model: KSS 0.891 (0.870-0.911), SF-PCS 0.832 (0.808-0.857), SF-MCS 0.835 (0.811-0.856), and OKS 0.816 (0.768-0.863). Our findings highlighted that ML models using clinical or multimodal data were capable to predict post-TKA dissatisfaction.

Multiple fractures of the femur: Case report, literature review, and proposal for a shared algorithm of treatment

Multiple fractures of the femur, defined for the purposes of this study as the association of three or more non-contiguous fractures on the same bone segment, is an exceedingly rare condition with an unknown incidence in the literature. A limited number of studies, mainly consisting of case reports or small case series, have addressed this topic, and no shared consensus or guidelines exist on what the ideal timing and sequence of multiple fracture fixation is. The present paper reports the clinical case of a 36 years old man who sustained a blunt chest injury, a non-concussive head injury, a displaced intracapsular fracture of the left femur (AO 31B2), a left diaphyseal multifragmentary fracture (AO 32B3), a supradiacondylar fracture of the distal end of the left femur (AO 33C1.1), a Hoffa fracture of the lateral left femoral condyle (AO 33B3.2 f), and a multifragmentary fracture of the left patella with bone loss (AO 34C3) due to a vehicular high-energy trauma. The patient was surgically treated by open reduction and internal fixation according to a proposed algorithm of treatment and reported excellent clinical and radiological outcomes at 32 months follow-up. The primary aim of this study is to describe our experience in the treatment of such complex fractures, by presenting our clinical and radiological results, and to propose a treatment algorithm. The secondary aim is to provide a comprehensive review of the literature on this topic.

Conversion of UKA to TKA using identical standard implants-How does it compare to primary UKA, primary TKA and revision TKA?

BACKGROUND

UKA is a well-established treatment option for anteromedial osteoarthritis of the knee, resulting in superior functional outcomes but also higher revision rates than TKA. This study aimed to compare the outcomes of UKA, TKA, UKA converted to TKA using identical standard implants and revised TKA to support clinical decision-making.

METHODS

In this study, we retrospectively examined 116 patients who underwent UKA, 77 patients who received TKA, 28 patients whose UKA was converted to TKA using identical standard implants, and 21 patients who had a one-stage revision of TKA. The mean age at operation was 66.5 years (39-90 years), with a mean BMI of 28.8 kg/m2 (17.4-58.8) and a mean follow-up period of four years (0.9-9.9 years). We assessed various PROMs, including Oxford Knee Score, UCLA score, KSS score, and a modified WOMAC-Score as well as patient satisfaction and ability to resume daily activities, work, and sports.

RESULTS

The highest patient satisfaction was seen in the UKA. All scores were significantly higher for UKA than for TKA, converted UKA, and revised TKA. None of the scores showed a significant inferiority of converted UKA to TKA. In the case of revision, two scores showed significantly better results for converted UKA than for revised TKA.

CONCLUSIONS

Our results indicated that patients initially treated with UKA did not have significantly worse functional outcomes after conversion to TKA, given the use of identical standard implants. This highlights the effectiveness of UKA as a therapeutic option with outcomes superior to those of primary TKA and the importance of a bone-sparing procedure. Conversely, revision TKA is linked to poorer functional outcomes compared to both primary arthroplasties.

Kinematic Alignment Technique Outperforms Mechanical Alignment in Simultaneous Bilateral Total Knee Arthroplasty: A Randomized Controlled Trial

BACKGROUND

The aim of this study was to compare the clinical results of kinematic alignment (KA) with those of mechanical alignment (MA) in single-stage bilateral total knee arthroplasty.

METHODS

In this double-blinded randomized controlled trial, 65 patients who had bilateral knee osteoarthritis underwent simultaneous bilateral total knee arthroplasty. One knee was randomly selected to be operated on with the calipered-KA technique and the other with MA. The participants were assessed via the Oxford Knee Score, Western Ontario and McMaster Universities Osteoarthritis Index questionnaire, and visual analog scale before the surgery and the same plus the Forgotten Joint Score at their last follow-up visit, 2 years postoperatively. Maximum knee flexion and the time reaching maximum knee flexion, named the recovery time, were also recorded. Hip-knee-ankle angle, medial proximal tibial angle, and lateral distal femoral angle were measured before and after the surgery using 3-joint-view radiographs.

RESULTS

At 2 years, there were significant differences between the KA and MA techniques in terms of duration of surgery, recovery time, and final Western Ontario and McMaster Universities Osteoarthritis Index, Forgotten Joint Score, and maximum flexion range in favor of KA (P < .05), but no significant difference in visual analog scale score or Oxford Knee Score. In patients who have a preferred knee, the KA knee was preferred over the MA knee by most patients. No prosthetic failure or revision was reported in either group.

CONCLUSIONS

The KA technique yields acceptable functional outcomes compared to the MA technique. The KA technique was associated with a shorter surgery time, a faster recovery time, and higher patient satisfaction in 2-year follow-ups. Larger multicenter studies with longer follow-ups are warranted to confirm these findings.

LEVEL OF EVIDENCE

I.

Porous Tantalum Metaphyseal Cones for Severe Femoral and Tibial Bone Defects in Revision Total Knee Arthroplasty are Reliable for Fixation at Mean 5-Year Follow-Up

BACKGROUND

Porous tantalum metaphyseal cones may facilitate reconstructions of severe bone defects during revision total knee arthroplasty (TKA), but there remains a paucity of data on their outcomes at mean 5 years of follow-up. This study reports the component survivorship, patient satisfaction, functional outcomes, radiographic osseointegration, and complications of revision TKA with porous tantalum metaphyseal cones at mid-term (mean 5-year) follow-up.

METHODS

This study included 152 patients who had a mean age of 66 years (range, 33 to 86 years) undergoing revision TKA with porous tantalum metaphyseal cones. Indications for surgery included aseptic loosening (n = 87, 57.3%), second-stage reimplantation for infection (n = 42, 27.6%), osteolysis with well-fixed components (n = 20, 13.2%), and periprosthetic fracture (n = 3, 2.0%). Component survivorship, clinical outcomes, radiographic outcomes, and any complications were recorded. The mean follow-up time was 5.6 years (range, 2.2 to 13.7).

RESULTS

Survivorship was 100% when the end point was revision of the metaphyseal cone (no cones were revised) and 83.8% (95% confidence interval: 77.9 to 90.2%) when the end point was reoperation for any reason at 5-year follow-up. Reoperations were performed for infection (n = 10), instability (n = 4), periprosthetic fracture (n = 2), and quadriceps rupture/dehiscence (n = 3). The mean patient satisfaction score was 78.8 ± 11.3 and the mean Forgotten Joint Score was 62.2 ± 16.7 at the final follow-up. The preoperative median University of California at Los Angeles score improved from 2 (interquartile range 2 to 3) to 6 points (interquartile range 5 to 6) (P < .001), and the preoperative Oxford knee score improved from 15.2 ± 3.8 to 39.4 ± 5.1 points (P < .001) at the final follow-up. All metaphyseal cones showed radiographic evidence of osteointegration without any subsidence or loosening.

CONCLUSIONS

Porous tantalum metaphyseal cones enabled robust reconstructions of severe femoral and tibial bone defects during revision TKA. These reconstructions were associated with excellent survivorship, improvements in functional outcomes, and reproducible radiographic osseointegration at mean 5-year follow-up. The most common reasons for reoperation were infection and instability.

Favorable early outcomes of medial unicompartimental knee arthroplasty in active patients presenting a degenerative medial meniscus root tear with meniscal extrusion and mild radiographic osteoarthritis

INTRODUCTION

There is only limited literature available evaluating the preferable treatment for active mid-age or elderly patients presenting with a degenerative medial meniscus root tear (d-MMRT) with medial meniscal extrusion (MME) and early-phase radiographic osteoarthritis (OA), failing to provide solid evidence. The aim of this study was to evaluate early outcomes of medial unicompartimental arthroplasty (mUKA) in active patients presenting a d-MMRT with meniscal extrusion and mild radiographic OA of the knee. To prove this claim we hypothesized that (1) patients with a d-MMRT with initial grade 1-3 KL OA of the medial compartment of the knee present the same pre-operative symptoms as patients with an end-stage grade 4 K-L OA, and that (2) those patients with d-MMRT and low-grade OA achieve the same early clinical and functional outcomes when treated with mUKA compared to patients with end-stage medial OA.

METHODS

We reviewed the prospectively collected data of 185 patients undergoing robotic-assisted image-based mUKA from January 2021 to July 2022 at a single Institution. We identified two different cohorts of non-consecutive patients: a group of 24 patients undergoing mUKA surgery following d-MMRT combined with K-L grades 1-3 OA (group 1), and a group of 161 patients who underwent mUKA but presenting with an end-stage bone-on-bone K-L grade 4 OA (group 2). Preoperative and postoperative clinical assessments at one-year follow-up included the Oxford Knee Score (OKS), 5-level EQ-5D version (EQ-5D-5L score), and a standard weight-bearing X-ray protocol. The paired t-test was used to compare clinical outcomes and radiologic values of the two cohorts and in-between the two cohorts. Statistical significance was set at p < 0.05.

RESULTS

The mean follow-up for group 1 was 16.4 ± 2.5 months, and the mean age at the time of operation was 63 ± 8.6 years with a mean time from diagnosis to intervention of 53 ± 47.5 days. Preoperative impairment was greater in group 1 compared to group 2, but with no significant difference. Postoperatively, both groups showed excellent mean outcomes at 1-year follow-up, with no significant difference. The mean preoperative HKA, mPTA, and LDFA were 176.3 ± 3.1, 88.1 ± 2.3, and 86.6 ± 1.7 respectively. The mean postoperative HKA, coronal femoral component angle, and coronal tibial component angle were 179.1 ± 2.6, 87.2 ± 2.3, and 87.2 ± 3.3. No difference was found between preoperative age, BMI, between the two cohorts.

CONCLUSIONS

Favorable early clinical outcomes were obtained after mUKA in active mid-age and elderly patients presenting with degenerative medial meniscus root tear and mild isolated medial OA. Patients with mild no bone-on-bone OA but with degenerative medial meniscus root tear and medial meniscal extrusion presented the same or worse pre-operative symptoms as patients with end-stage medial OA and benefit the same from mUKA.

Unveiling distinct kinematic profiles among total knee arthroplasty candidates through clustering technique

BACKGROUND

Characterizing the condition of patients suffering from knee osteoarthritis is complex due to multiple associations between clinical, functional, and structural parameters. While significant variability exists within this population, especially in candidates for total knee arthroplasty, there is increasing interest in knee kinematics among orthopedic surgeons aiming for more personalized approaches to achieve better outcomes and satisfaction. The primary objective of this study was to identify distinct kinematic phenotypes in total knee arthroplasty candidates and to compare different methods for the identification of these phenotypes.

METHODS

Three-dimensional kinematic data obtained from a Knee Kinesiography exam during treadmill walking in the clinic were used. Various aspects of the clustering process were evaluated and compared to achieve optimal clustering, including data preparation, transformation, and representation methods.

RESULTS

A K-Means clustering algorithm, performed using Euclidean distance, combined with principal component analysis applied on data transformed by standardization, was the optimal approach. Two unique kinematic phenotypes were identified among 80 total knee arthroplasty candidates. The two distinct phenotypes divided patients who significantly differed both in terms of knee kinematic representation and clinical outcomes, including a notable variation in 63.3% of frontal plane features and 81.8% of transverse plane features across 77.33% of the gait cycle, as well as differences in the Pain Catastrophizing Scale, highlighting the impact of these kinematic variations on patient pain and function.

CONCLUSION

Results from this study provide valuable insights for clinicians to develop personalized treatment approaches based on patients' phenotype affiliation, ultimately helping to improve total knee arthroplasty outcomes.

Comparison ultrasound-guided adductor canal block and surgeon-performed block for pain management after total knee arthroplasty: a prospective randomized controlled study

OBJECTIVE

Adductor canal block (ACB) is widely performed for postoperative analgesia for total knee arthroplasty (TKA). The aim of this study is to compare surgeon-assisted and anesthesiologist-assisted (ultrasound-guided) adductor blocks in terms of postoperative analgesic efficacy.

METHODS

This study was designed as a double-blind, prospective and randomized trial. A total of 240 participants were randomly allocated to three groups: one where the surgeon performed the adductor canal block (ACBs), another where it was conducted by an anesthetist with ultrasound guidance (ACBa), and a third group without the adductor block. The follow-up management after the Total Knee Arthroplasty (TKA) procedure occurred on the first, third, and tenth days, as well as the twelfth week. Outcome measures comprised pain assessment using the Visual Analog Scale (VAS) and monitoring opioid analgesic consumption.

RESULTS

No significant differences in demographic profiles were observed between the groups. Groups ACBa and ACBs exhibited significantly lower VAS scores compared to the control group at both 3 and 12 h after surgery, with group ACBa showing the lowest VAS scores among all groups. However, at 1 day, 3 days, 10 days and 12 weeks after surgery, there was no significant difference in VAS scores between the ACBa and ACBs groups. On the first three days, the ACBa group had the lowest opioid consumption and the lowest total opioid consumption. The differences in VAS scores between the groups began to decrease on the first day after surgery.

CONCLUSION

The adductor canal block (ACB) has been demonstrated to be an effective method of reducing pain in patients undergoing total knee replacement (TKR) in the postoperative period. Nevertheless, despite the pronounced impact that ACB performed by an anesthesiologist under ultrasound guidance has on VAS scores according to intraoperative ACB by surgeons, its effect on clinical outcomes has not been demonstrated.

TRIAL REGISTRATIONS

This study was retrospectively registered with the Clinical Trials Registry Platform on July 31, 2024 (NCT06533085).

A literature review and expert consensus statement on diagnostics in suspected metal implant allergy

BACKGROUND

Although rare, allergic reactions to metal implants represent a diagnostic challenge in view of missing guidelines.

OBJECTIVES

To develop an European expert consensus on characteristics of metal allergy reactions and the utility of various diagnostic tools in suspected metal implant allergy.

METHODS

A nominal group technique (NGT) was applied to develop consensus statements. Initially an online literature database was created on a secure server to enable a comprehensive information. Twenty-three statements were formulated on potential aspects of metal implant allergy with a focus on diagnostics and grouped into five domains. For the consensus development, the panel of 12 experts initially did refine and reformulate those statements that were ambiguous or had unclear wording. By face-to-face (9/12) or virtual participation (3/12), an anonymous online voting was performed.

RESULTS

Consensus (≥80% of agreement) was reached in 20/23 statements. The panel agreed that implant allergy despite being rare should be considered in case of persistent unexplained symptoms. It was, however, recommended to allow adequate time for resolution of symptoms associated with healing and integration of an implant. Obtaining questionnaire-aided standardized medical history and standardized scoring of patient outcomes was also considered an important step by all experts There was broad consensus regarding the utility/performance of patch testing with additional late reading. It was recognized that the lymphocyte transformation test (LTT) has to many limitations to be generally recommended. Prior to orthopaedic implant, allergy screening of patients without a history of potential allergy to implant components was not recommended.

CONCLUSIONS

Using an expert consensus process, statements concerning allergy diagnostics in suspected metal implant allergy were created. Areas of nonconsensus were identified, stressing uncertainty among the experts around topics such as preoperative testing in assumed allergy, histological correlate of periimplant allergy and in vitro testing, which underscores the need for further research.