AdipoRon reduces TGFß1-mediated collagen deposition in vitro and alleviates knee stiffness in vivo.

Arthrofibrosis, which causes joint motion restrictions, is a common complication following total knee arthroplasty (TKA). Key features associated with arthrofibrosis include myofibroblast activation, knee stiffness, and excessive scar tissue formation. We previously demonstrated that adiponectin levels are suppressed within the knee tissues of patients affected by arthrofibrosis and showed that AdipoRon, an adiponectin receptor agonist, exhibited anti-fibrotic properties in human mesenchymal stem cells. In this study, the therapeutic potential of AdipoRon was evaluated on TGFß1-mediated myofibroblast differentiation of primary human knee fibroblasts and in a mouse model of knee stiffness. Picrosirius red staining revealed that AdipoRon reduced TGFß1-induced collagen deposition in primary knee fibroblasts derived from patients undergoing primary TKA and revision TKA for arthrofibrosis. AdipoRon also reduced mRNA and protein levels of ACTA2, a key myofibroblast marker. RNA-seq analysis corroborated the anti-myofibrogenic effects of AdipoRon. In our knee stiffness mouse model, 6 weeks of knee immobilization, to induce a knee contracture, in conjunction with daily vehicle (DMSO) or AdipoRon (1, 5, and 25 mg/kg) via intraperitoneal injections were well tolerated based on animal behavior and weight measurements. Biomechanical testing demonstrated that passive extension angles (PEAs) of experimental knees were similar between vehicle and AdipoRon treatment groups in mice evaluated immediately following immobilization. Interestingly, relative to vehicle-treated mice, 5 mg/kg AdipoRon therapy improved the PEA of the experimental knees in mice that underwent 4 weeks of knee remobilization following the immobilization and therapy. Together, these studies revealed that AdipoRon may be an effective therapeutic modality for arthrofibrosis.

Cost and outcomes of Hospital-based Usual cAre versus Tele-monitor self-directed Rehabilitation (HUATR) in patients with total knee arthroplasty: A randomized, controlled, non-inferiority trial.

OBJECTIVE: To evaluate the clinical efficacy and cost-effectiveness of telemonitored self-directed rehabilitation (TR) compared with hospital-based rehabilitation (HBR) for patients with total knee arthroplasty (TKA). DESIGN: In this randomized, non-inferiority clinical trial, 114 patients with primary TKA who were able to walk independently preoperatively were randomized to receive HBR (n = 58) or TR (n = 56). HBR comprised at least five physical therapy sessions over 10 weeks. TR comprised a therapist-led onboarding session, followed by a 10-week unsupervised home-based exercise program, with asynchronous monitoring of rehabilitation outcomes using a telemonitoring system. The primary outcome was fast-paced gait speed at 12 weeks, with a non-inferiority margin of 0.10 m/s. For economic analysis, quality-adjusted-life-years (QALY) was the primary economic outcome (non-inferiority margin, 0.027 points). RESULTS: In Bayesian analyses, TR had >95% posterior probability of being non-inferior to HBR in gait speed (week-12 adjusted TR-HBR difference, 0.02 m/s; 95%CrI, -0.05 to 0.10 m/s; week-24 difference, 0.01 m/s; 95%CrI, -0.07 to 0.10 m/s) and QALY (0.006 points; 95%CrI, -0.006 to 0.018 points). When evaluated from a societal perspective, TR was associated with lower mean intervention cost (adjusted TR-HBR difference, -S$227; 95%CrI, -112 to -330) after 24 weeks, with 82% probability of being cost-effective compared with HBR at a willingness to pay of S$0/unit of effect for the QALYs. CONCLUSIONS: In patients with uncomplicated TKAs and relatively good preoperative physical function, home-based, self-directed TR was non-inferior to and more cost-effective than HBR over a 24-week follow-up period. TR should be considered for this patient subgroup.

Outcomes of different perioperative management strategies of patients on chronic anticoagulation in elective total hip and knee arthroplasty: a systematic review.

INTRODUCTION: There are currently different management guidelines for patients undergoing elective total hip arthroplasty (THA) or total knee arthroplasty (TKA) that are on long-term anticoagulation. The timing of discontinuation and restarting the anticoagulation is challenging during the postoperative care, which often involves general practitioners and physiotherapists. METHODS: The systematic review followed the PRISMA guidelines and included 3 databases: PubMed/MEDLINE, EMBASE, and Web of Science Core Collection. It was registered in the International Prospective Register for Systematic Reviews and Meta-analysis (PROSPERO) under the registration number: CRD42023408906. The risk of bias assessment was performed using the Methodological index for non-randomized studies (MINORS) criteria. RESULTS: Six retrospective studies involving 727 patients with therapeutic anticoagulation (1,540 controls) for elective THA, TKA and revision arthroplasty have been included. The follow-up ranged from 30 days to 1 year postoperatively. All studies evaluated outcomes of warfarin therapeutic anticoagulation versus prophylactic dosages of one or more of the following: warfarin, aspirin, low-molecular-weight heparin (LMWH) and unfractionated low-dose heparin (UFH). One study did not discontinue therapeutic anticoagulation. Two studies reported no significant differences in complications between groups, whilst 3 studies had significantly higher rates of superficial wound infections, revision surgeries, postoperative haematomas, and prosthetic joint infections (PJI). CONCLUSION: Different anticoagulation-related perioperative management strategies achieve different outcomes following elective arthroplasty in patients with therapeutic chronic anticoagulation. There is contradictory evidence regarding the need for the discontinuation of therapeutic warfarin. Retrospective data showed that individual risk stratification with multi-modal prophylaxis resulted in minimal complications. LEVEL OF EVIDENCE: Systematic Review of Level III studies.

The efficacy and safety of perioperative glucocorticoid for total knee arthroplasty: a systematic review and meta-analysis.

BACKGROUND: An increasing number of individuals undergo total knee arthroplasty (TKA), which can result in pain, limited motor function and adverse complications such as infection, nausea and vomiting. Glucocorticoids have been shown anti-inflammatory and antiemetic effects, but can also elevate blood glucose levels and increase the risk of wound infection. Thus, it is essential to investigate the efficacy and safety of glucocorticoid usage in TKA. METHOD: A comprehensive systematic search of PubMed, Medline, EMBASE, Cochrane databases, to identify relevant randomized controlled trials (RCTs) of glucocorticoid application in TKA. The primary outcomes assessed were the postoperative pain assessment. Secondary outcomes included the range of motion in knee joint, levels of inflammatory cytokines, adverse complications, and the length of hospital stay. RESULTS: Thirty-six randomized controlled trials were included in the final analysis. The glucocorticoid group exhibited significant reduction in the resting VAS scores on postoperative days 1, 2 (POD1, 2)and postoperative 3 months (POM3), as well as decreased morphine consumption on POD1 and increased range of motion (ROM) in knee joint on POD1, 3. Additionally, the glucocorticoid group exhibited decreased levels of postoperative inflammatory cytokines and the incidence of PONV along with a shorter length of hospital stay. The blood glucose concentration was significantly increased in the glucocorticoid group on POD1 compared with the control group. While the blood glucose on POD2 and occurrence of postoperative adverse complications were similar between two groups including wound infection and venous thrombosis. The periarticular injection analgesia (PIA) group demonstrated lower VAS scores on POD2 comparing to the systemic administration (SA) group according to two studies. However, there was no significant difference of the resting VAS on POD1 and POD2 between PIA and SA group across all studies. CONCLUSION: Perioperative glucocorticoids treatment in TKA significantly reduced short-term pain score and opioid-use which was probably not patient relevant. The application of glucocorticoids in TKA implied a beneficial trend in analgesic, anti-inflammatory, and antiemetic effects, as well as improved range of motion and shortened hospital stay. While it will not increase the risk of continued high glucose, postoperative wound infection and venous thrombosis.

A systematic review and meta-analysis of hybrid vs. cemented stems - which method is more optimal for revision total knee arthroplasty?

INTRODUCTION: The number of primary and revision Total Knee Arthroplasty (TKA) cases are expected to increase in future. There are various advantages and disadvantage to employing either of the two main types of stem fixation methods - cemented or hybrid technique. This review aimed to study the most optimal fixation method for revision TKAs by comparing radiological outcomes and re-revision rates. METHODS: A systematic review and meta-analysis was performed using PubMed and Cochrane Library from 2010 to identify studies explicitly comparing outcomes between cemented against hybrid fixation revision TKA techniques, with a minimum follow up of at least 24 months. A total of 8 studies was included in this review. Egger's test and visual inspection of the funnel plot did not reveal publication bias. RESULTS: There was no statistically significant difference in radiological failure and loosening (OR 0.79, CI 0.37-1.66, I2 = 29%, p = 0.22), all causes of re-revision (OR 1.03, CI 0.73-1.44, I2 = 0%, p = 0.56) and aseptic revision (OR 0.74, CI 0.27-2.02, I2 = 0%, p = 0.41) between cemented and hybrid techniques. Functional and pain outcomes compared between the two fixation techniques were largely similar across the studies included in this meta-analysis. CONCLUSION: Despite a trend favouring hybrid stems in revision TKA, current evidence revealed that radiological outcomes and re-revision rates are largely similar between cemented and hybrid fixation techniques.

Tourniquet does not affect intraoperative kinematics during total knee arthroplasty: Results of a prospective study using a robotic assistance system.

PURPOSE: Tourniquet use during total knee arthroplasty (TKA) remains controversial. There are limited data demonstrating the effect of tourniquet use on flexion and extension gaps. The use of a tourniquet can theoretically affect the kinematics of the knee joint, specifically the extension and flexion gaps and the laxity, by mechanically compressing the soft tissues including the muscles above the knee joint. Therefore, this study was designed to prospectively evaluate changes in flexion and extension gaps with and without the use of a tourniquet. METHODS: The following prospective study included 50 consecutive patients who underwent TKA using a surgical robot. The inclusion criteria were advanced osteoarthritis (OA) and varus-alignment or valgus-alignment <3° (hip-knee-ankle angle, standing long-leg X-ray), and the exclusion criteria were BMI >35 kg/m2 and mechanical axis in >3° valgus. A CR-TKA was performed, and the medial and lateral gaps (in mm) throughout the full range of motion in 10° increments were recorded. The procedure was conducted both with and without an applied tourniquet (350 mmHg). RESULTS: No significant differences were observed in the medial joint space. By contrast, the lateral gap showed significant differences in 10-20° of flexion (with a tourniquet 1.9 mm vs. without a tourniquet 2.1 mm, p = 0.018), 20-30° (1.6 vs. 1.8 mm, p = 0.02), 100-110° (0.9 vs. 1.1 mm, p = 0.021), and 110-120° (0.8 vs. 1 mm, p = 0.038). Thus, at the above degrees of flexion on the lateral side, there was a decrease in the mean of 0.2 mm with the use of a tourniquet. CONCLUSION: Although the use of a tourniquet showed a detectable change in the lateral gap in four 10° segments of flexion, clinical relevance with an average difference of 0.2 mm is not achieved. Thus, the use of a tourniquet in TKA can still be advocated based on the presented data. LEVEL OF EVIDENCE: Level I.

Inverse kinematic total knee arthroplasty using conventional instrumentation restores constitutional coronal alignment.

PURPOSE: Restricted inverse kinematic alignment (iKA) is a contemporary alignment strategy for total knee arthroplasty (TKA), commonly performed with robotic assistance. While superior clinical results are reported for kinematic-type alignment strategies, registry data indicate no survivorship benefit for navigation or robotic assistance. This study aimed to determine the efficacy of an instrumented, restricted iKA technique for achieving patient-specific alignment. METHODS: Seventy-nine patients undergoing 84 TKAs (five bilateral procedures) using an iKA technique were included for preoperative and postoperative lower limb alignment analysis. The mean age was 66.5 (range: 43-82) with 33 male and 51 female patients. Artificial intelligence was employed for radiographic measurements. Alignment profiles were classified using the Coronal Plane Alignment of the Knee (CPAK) system. Preoperative and postoperative alignment profiles were compared with subanalyses for preoperative valgus, neutral and varus profiles. RESULTS: The mean joint-line convergence angle (JLCA) reduced from 2.5° to -0.1° postoperatively. The mean lateral distal femoral angle (LDFA) remained unchanged postoperatively, while the mean medial proximal tibial angle (MPTA) increased by 2.5° (p = 0.001). By preservation of the LDFA and restoration of the MPTA, the mean hip knee ankle angle (HKA) moved through 3.5° varus to 1.2° valgus. The CPAK system was used to visually depict changes in alignment profiles for preoperative valgus, neutral and varus knees; with 63% of patients observing an interval change in classification. CONCLUSION: Encouraged by the latest evidence supporting both conventional instrumentation and kinematic-type TKA strategies, this study describes how a restricted, conventionally instrumented iKA technique may be utilised to restore constitutional lower limb alignment. LEVEL OF EVIDENCE: Level III.

Individualised compared to off-the-shelf total knee arthroplasty results in lower and less variable patellar tilt.

PURPOSE: The purpose of this study was to compare postoperative patellar tilt at 4 months follow-up in a consecutive series of randomised patients that received individualised or off-the-shelf (OTS) primary total knee arthroplasty (TKA). The hypothesis was that patellar tilt would be lower and less variable in patients who received individualised TKA compared to patients who received OTS TKA. METHODS: A consecutive series of 385 patients randomised (1:1) to receive either OTS TKA or individualised TKA were analysed. Pre- and postoperative radiographs at 4 months were obtained of weight-bearing long leg, anterior-posterior and lateral knee views and a skyline view at 30° of flexion. Postoperative patellar tilt was measured between the anterior femoral line and patellar resection surface (ß) and the anterior femoral line and mediolateral patellar axis (σ). Postoperative patellar tilt (absolute value) was compared between the individualised and OTS TKA groups based on preoperative phenotypes of their femoral mechanical angle, tibial mechanical angle and hip-knee-ankle angle. Variability in postoperative patellar tilt was compared using the 95% confidence intervals (CIs). RESULTS: Comparisons of baseline patient characteristics revealed no difference between the individualised and OTS TKA groups. Comparison of absolute postoperative patellar tilt revealed significant differences between individualised and OTS TKA (|ß|, 1.0° ± 1.0° and 2.5° ± 2.2°, respectively, p < 0.001; |σ|, 1.7° ± 1.6° and 2.8° ± 2.3°, respectively, p < 0.001). The 95% CI of postoperative patellar tilt (|ß|) was narrower in patients that received individualised compared to OTS TKA (0.0° to 3.8° and 0.1° to 8.3°, respectively), irrespective of their preoperative phenotype. CONCLUSION: Patients who underwent individualised TKA had lower and less variable postoperative patellar tilt than those with OTS TKA, irrespective of preoperative phenotype. Individualised TKA allows the decoupling of the tibiofemoral and patellofemoral joints, replicating anatomical trochlear orientation and improving patellar tilt, which could facilitate better clinical outcomes. CLINICAL TRIAL REGISTRATION: This study constitutes a part of a larger registered randomised controlled trial comparing patient satisfaction following OTS versus individualised TKA (NCT04460989). LEVEL OF EVIDENCE: Level II.

Tibia-first, gap-balanced patient-specific alignment restores bony phenotypes and joint line obliquity in a great majority of varus and straight knees and normalises valgus and severe varus deformities.

PURPOSE: The present study focuses on testing the capability of a restricted tibia-first, gap-balanced patient-specific alignment technique (PSA) to restore bony morphology and phenotypes. METHODS: Three-hundred and sixty-seven patients were treated with navigated total knee arthroplasty and tibia-first gap-balanced PSA technique. Boundaries for medial proximal tibial angle were 86°-92°, mechanical lateral distal femoral angle 86°-92°, and hip-knee-ankle angle 175°-183°. Knees were classified by coronal plane alignment of the knee (CPAK), with subsequent analyses comparing pre- and postoperative distributions. Phenotype classification within CPAK groups assessed pre- and postoperative distributions. RESULTS: Preoperatively, the largest CPAK group was type II (30.8%), followed by type I (20.5%) and type V (17.8%). Postoperatively, type II remained the largest group (39%), followed by type V (30%). All groups with varus/valgus deformities (I, III, IV and VI) became smaller. While in straight legs (II, IV), the CPAK was restored in more than 70%-75%, in varus groups (I, IV) in 40%-50% and in valgus (III and VI) in 5%-18%. The joint line obliquity remained the same in the majority of knees (straight >75%; varus 63%-80%; valgus VI 95%), with the exception of CPAK III (40%). The phenotype analysis showed for straight legs a phenotype restoration of 85%, for varus 94% and for valgus 37%. Joint line convergence angle was reduced significantly in all groups from 1.8°-4.3° preoperatively to 0.6°-1.2° postoperatively. CONCLUSION: PSA restores bony phenotypes and joint line obliquity in the majority of straight and varus knees, while most of the valgus and extreme varus knees are normalised. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Similar QALY gain in primary and revision knee arthroplasty: A cost analysis and Markov model.

PURPOSE: The aim of this study is to investigate the cost-effectiveness of revision total knee arthroplasty compared to primary total knee arthroplasty in terms of cost-per-quality-adjusted life year (QALY). METHODS: Data were retrieved for all primary and revision total knee replacement (TKA) procedures performed at a tertiary Swiss hospital between 2006 and 2019. A Markov model was created to evaluate revision risk and we calculated lifetime QALY gain and lifetime procedure costs through individual EuroQol 5 dimension (EQ-5D) scores, hospital costs, national life expectancy tables and standard discounting processes. Cost-per-QALY gain was calculated for primary and revision procedures. RESULTS: EQ-5D data were available for 1343 primary and 103 revision procedures. Significant QALY gains were seen following surgery in all cases. Similar, but significantly more QALYs were gained following primary TKA (PTKA) (5.67 ± 3.98) than following revision TKA (RTKA) (4.67 ± 4.20). Cost-per-QALY was €4686 for PTKA and €10,364 for RTKA. The highest average cost-per-QALY was seen in two-stage RTKA (€12,292), followed by one-stage RTKA (€8982). CONCLUSION: RTKA results in a similar QALY gain as PTKA. The costs of achieving health gain are two to three times higher in RTKA, but both procedures are highly cost-effective. LEVEL OF EVIDENCE: Economic level II.

Improvement in functional outcome 1 year after nonsurgical multidisciplinary treatment for chronic pain after total knee arthroplasty: A prospective cohort study.

PURPOSE: The purpose of this study was to evaluate a multidisciplinary intervention developed for patients with debilitating chronic pain after total knee arthroplasty (TKA) unresponsive to existing treatment options. METHODS: A treatment-based prospective cohort study was caried out in 30 TKA patients with debilitating chronic pain at least 1 year after TKA. The treatment was a multidisciplinary intervention. Main inclusion criteria: no indication for surgery. Primary outcome was function measured by KOOS-PS, OKS, OKS-APQ and WORQ. Secondary outcome measures were pain, fear of movement, self-efficacy, quality of life (QoL), health care and pain medication use, work rehabilitation and patient satisfaction. The assessments took place pre- and directly posttreatment, at 1, 3 and 12 months follow-up. The clinical relevance was assessed by predefined minimal important clinical change (MCIC). RESULTS: At baseline patients were on average 64.7 (±7.9) years old, 67% were female, and they had knee pain for 42 (10-360) months. The results at 12-month follow-up: first, a significant improvement was shown in function, pain, fear of movement, self-efficacy and QoL. Second, in 38.5%-69.2% of patients clinical relevant improvement was shown for functional outcome, 31% for pain, and 50% for self-efficacy. Third, 42% of patients reported 'no healthcare use in the past three months'. CONCLUSION: One year after a multidisciplinary treatment a clinically relevant improvement was shown in terms of function, pain, self-efficacy and QoL. It seems to be a promising treatment option in this difficult-to-treat patient group with debilitating chronic pain after TKA. Future research should examine the effect of the treatment in a larger study population, considering a control group, and focusing on the working population and evaluating cost-efficacy. LEVEL OF EVIDENCE: Level II.

Clinical outcomes following transtibial medial meniscal root repair are maintained at long-term follow-up.

PURPOSE: To evaluate long-term outcomes of patients treated with posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and to identify patient surgical and magnetic resonance imaging (MRI) characteristics associated with improved outcomes. METHODS: This was a single-centre, retrospective study evaluating patients who had undergone a PMMR repair using a transtibial suture pullout technique with two locking cinch sutures. This was performed as a follow-up to previously published 2-year and 5-year outcome studies, using the same cohort. All patients from the prior short-term and midterm studies were invited to participate. Patient-reported outcome (PROs) scores, including the International Knee Documentation Committee (IKDC) and Lysholm scores, were collected. Previously collected demographic data were updated based on review of the electronic medical record. Patient outcomes were assessed preoperatively, as well as at 2-year, 5-year and 8-year postoperatively. MRI outcome measurements were assessed at 2-year and 5-year follow-ups. All statistical analysis was performed using SPSS version 26. RESULTS: Seventeen patients of the original 18 patients (94.4%) were included in the final analysis. Additionally, three patients who had additional ipsilateral surgery were excluded from the analysis of PROs. The IKDC score significantly increased from 44.7 ± 11.6 at preoperative baseline to 71.2 ± 21.3 at 8-year post-operation (p = 0.001). There were no significant differences in IKDC score between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). The Lysholm score significantly increased from 49.6 ± 7.3 at preoperative baseline to 76.4 ± 17.2 at 8-year follow-up (p < 0.001). There was no significant difference in Lysholm scores between 2-year and 8-year follow-ups (p = n.s.) or 5-year and 8-year follow-ups (p = n.s.). A linear regression analysis found that 5-year IKDC scores were significantly correlated with 8-year IKDC scores (ß = 0.681, p = 0.038). At 8-year follow-up, four (23.5%) patients required additional procedures on their operative knee (one total knee arthroplasty conversion). CONCLUSION: Patients treated with repair of PMMRT had maintenance of clinical outcome improvements at long-term follow-up despite worsening MRI outcomes at short-term and medium-term follow-ups. While a high proportion of patients required additional procedures on their operative knee at 8-year follow-up, few of these patient's additional procedures were related to failure of their primary surgery. Providers and patients may expect durable clinical outcomes following the repair of PMMRT, irrespective of radiographic appearance. LEVEL OF EVIDENCE: Level IV.

Knee kinematics are not different between asymmetrical and symmetrical tibial baseplates in total knee arthroplasty: A fluoroscopic analysis of step-up and lunge motions.

PURPOSE: This clinical fluoroscopy study investigated knee kinematics of two different cemented fixed-bearing, posterior-stabilised (PS) total knee arthroplasty (TKA) designs: an asymmetric tibial component including an asymmetric insert designed to optimise personalised balance and fit and its precursor symmetrical design with symmetric insert. METHODS: A consecutive series of patients (16 TKAs from each treatment group) participating in a randomised controlled trial comparing TKA migration was included. The exclusion criterion was the use of walking aids. Flat-panel fluoroscopic recordings of step-up and lunge motions were acquired 1-year postoperatively. Medial and lateral contact points (CPs) were determined to calculate CP displacement, femoral axial rotation and pivot position. Using linear mixed-effects modelling techniques, kinematics between TKA designs were compared. RESULTS: During knee extension between 20° flexion and full extension, the CPs moved anteriorly combined with a small internal femoral rotation (a screw-home mechanism). Whereas CP movement was reversed: femoral rollback, external femoral rotation while flexing the knee between full extension and 20° knee flexion, At larger flexion angles, femoral axial rotation (FAR) occurred around a lateral pivot point both during step-up and lunge. The symmetric design had a 2.3° larger range of FAR compared to the asymmetric design during lunge (p = 0.02). All other kinematics were comparable. CONCLUSION: Despite the differences in design, this study showed that the asymmetric and symmetric PS TKA designs had mostly comparable knee kinematics during step-up and lunge motions. It is therefore expected that the functionality of the successor TKA design is similar to that of its precursor design. LEVEL OF EVIDENCE: Level II, prospective comparative study.

Tibial plateau fractures are associated with poor functional outcomes and a low conversion rate to total knee arthroplasty.

PURPOSE: The aim of this study was to analyse the functional outcome and the conversion rate to total knee arthroplasty (TKA) after surgically treated tibial plateau fractures (TPF). METHODS: All patients undergoing surgical treatment of TPF at a single institution between January 2003 and December 2019 were retrospectively reviewed. The Knee injury and Osteoarthritis Outcome Score (KOOS) and Tegner activity scale (TAS) were collected. The conversion rate to TKA was examined 2, 5, 7 and 10 years after surgical treatment of TPF. RESULTS: Ninety-four patients, with a mean follow-up of 110.6 months (±60.0), were included in the functional outcome assessment. Mean KOOS scores were 75.4 for symptoms, 80.6 for pain, 84.3 for activities of daily living (ADL), 59.5 for sports and 61.3 for QOL. All subscales were significantly lower on the injured side compared with the contralateral leg. Lower KOOS was observed in patients with hardware removal and Schatzker type 5 and 6 injuries. Median TAS was postinjury (4) significantly lower than preinjury (5) (p < 0.001). The conversion rate to TKA was 6.3%, 10.9%, 11.7% and 12.2% after 2,5,7 and 10 years of follow-up, respectively. Patients undergoing TKA were older than patients with no conversion to TKA (2 years follow-up 53.8 vs. 64.5 years, p = 0.026). CONCLUSION: TPFs decrease the function of the knee when compared with the contralateral side and to the preoperative condition. Bicondylar fractures are associated with worse functional outcomes. A conversion rate to TKA of 12.2% was found at 10 years follow-up. LEVEL OF EVIDENCE: Level III.

Enhancing soft tissue balance: Evaluating robotic-assisted functional positioning in varus knees across flexion and extension with quantitative sensor-guided technology.

PURPOSE: Functional implant positioning (FIP) for total knee arthroplasty (TKA) is an evolution of kinematic alignment based on preoperative CT scan and robotic-assisted technology. This study aimed to assess the ligament balancing of image-based robotic-assisted TKA in extension, mid-flexion and flexion with an FIP using intraoperative sensor-guided technology. The hypothesis was that image-based robotic-assisted TKA performed by FIP would achieve ligament balancing all along the arc of knee flexion. METHODS: This prospective monocentric study included 47 consecutive patients with varus knees undergoing image-based robotic-assisted TKA performed with FIP. After robotic-assisted bone cuts, trial components were inserted, and soft tissue balance was assessed using sensor-guided technology at 10°, 45° and 90° of knee flexion. A mediolateral balanced knee was defined by an intercompartmental pressure difference (ICPD) ≤ 15 lbf and medial and lateral compartment pressure ≤60 lbf. The mean age was 71.6 years old ±6.7, the mean BMI was 29.0 kg/m2 ± 4.9 and the mean preoperative HKA was 174° ± 5 [159; 183]. RESULTS: The mean postoperative knee alignment was 177.0° ± 2.2° [172; 181]. There were 93.6% of balanced knees (n = 44) at 10 and 90° of knee flexion versus 76.6% (n = 36) at 45° of knee flexion with a significant difference (p = 0.014). Median ICPD at 10, 45 and 90° of knee flexion were, respectively, 7.0 (interquartile range [IQR]: 9), 11.0 (IQR: 9.5) and 8.0 (IQR: 9.0). Pairwise analyses revealed differences for ICPD at 45° versus ICPD at 10° (p = 0.003) and ICPD at 90° versus ICPD at 45° (p = 0.007). CONCLUSION: FIP with an image-based robotic-assisted system allowed the restoration of a well-balanced knee at 10° and 90° of flexion in varus knees. Nevertheless, some discrepancies occurred in midflexion, and more work is needed to understand ligament behaviour all along the arc of knee flexion. LEVEL OF EVIDENCE: Level II.

Mechanically aligned total knee arthroplasty does not yield uniform outcomes across all coronal plane alignment of the knee (CPAK) phenotypes.

PURPOSE: Patient dissatisfaction rates following total knee arthroplasty (TKA) reported in the literature reach 20%. The optimal coronal alignment is still under debate. The aim of this retrospective study was to compare clinical outcomes in different coronal plane alignment of the knee (CPAK) phenotypes undergoing mechanically aligned (MA) TKA. The hypothesis was that knees with preoperative varus arithmetic hip-knee-ankle angle (aHKA) would achieve inferior clinical outcomes after surgery compared to other aHKA categories. Additionally, another objective was to assess CPAK phenotypes distribution in the study population. METHODS: A retrospective selection was made of 180 patients who underwent MA TKA from April 2021 to December 2022, with a 1-year follow-up. Coronal knee alignment was classified according to the CPAK classification. Clinical outcome evaluations were measured using the Knee Society Score (KSS), Oxford Knee Score (OKS), Short Form Survey 12 and Forgotten Joint Score (FJS). Differences in clinical outcomes were considered statistically significant with a p value <0 .05. RESULTS: Patients with varus aHKA achieved significantly inferior outcomes at final follow-up compared to other aHKA categories in KSS pt. 1 (79.7 ± 17.2 vs. 85.6 ± 14.7; p = 0.028), OKS (39.2 ± 9.2 vs. 42.2 ± 7.2; p = 0.019) and FJS (75.4 ± 31.0 vs. 87.4 ± 22.9; p =0 .003). The most common aHKA category was the varus category (39%). The most common CPAK phenotypes were apex distal Types I (23.9%), II (22.8%) and III (13.3%). CONCLUSION: MA TKA does not yield uniform outcomes across all CPAK phenotypes. Varus aHKA category shows significantly inferior results at final follow-up. The most prevalent CPAK categories are varus aHKA and apex distal JLO, with phenotypes I, II and III being the most common. However, their gender distribution varies significantly. LEVEL OF EVIDENCE: Level IV.

CPAK classification cannot be used to determine segmental coronal extra-articular knee deformity.

PURPOSE: While the coronal plane alignment of the knee (CPAK) classification serves as a useful guide in personalising total knee arthroplasty (TKA), the extent of its correlation with segmental coronal extra-articular knee deformities remains uncertain. This study aims to investigate the potential correlation between CPAK matrix groups and segmental coronal extra-articular deformities in prearthritic knees, shedding light on the relationship between these two factors that seems to be both essential to perform personalised TKA. MATERIALS AND METHODS: A radiological assessment of 1240 nonarthritic knees was performed by evaluating lower limb measurements following the protocol established by Paley et al. Subsequently, all knees were classified into their respective CPAK matrix groups. In our quest to discern any correlation between the CPAK matrix groups and the presence of segmental coronal extra-articular knee deformities, nine potential coronal extra-articular deformity phenotype (CEDP) groupswere identified based on medial proximal tibial angle (MPTA) and mechanical lateral distal femoral angle (mLDFA). Neutral values for MPTA and mLDFA were set at 90.0° ± 3.0° and then at 87.0° ± 2.0°. Each CPAK matrix group underwent detailed coronal morphology analysis and then, segmental coronal extra-articular deformities were assessed by comparing them with the CEDP groups. RESULTS: The study revealed a mean hip-knee-ankle angle (HKA) of 178.6° ± 4.4°, mLDFA of 86.9° ± 2.5°, MPTA of 85.4° ± 2.4°, arithmetic HKA of -1.4° ± 3.2° and joint line obliquity of 172.5° ± 3.7°. The varus CPAK groups (I/IV/VII) included 435 patients, the neutral groups (II/V/VIII) comprised 630 patients and the valgus groups (III/VI/IX) had 175 patients. Notably, CPAK matrix groups were not distinctly associated with specific coronal extra-articular deformity phenotype (CEDP) groups. Particularly among the most common CPAK matrix groups (I/II/III/IV/V), there was a significant variation in segmental coronal extra-articular deformity patterns. Moreover, when neutral MPTA/mLDFA values were set at 87.0° ± 2.0°, the CPAK matrix groups exhibited even greater variability in coronal extra-articular deformities. CONCLUSION: The CPAK matrix groups do not exhibit a direct correlation with a specific extra-articular deformity pattern (CEDP), thus rendering them unsuitable for determining segmental coronal extra-articular knee deformities. LEVEL OF EVIDENCE: Level III, retrospective diagnostic study.

Anatomic Referencing of the Distal Femur in Total Knee Arthroplasty: The Impact of Orientation on Femoral Component Size.

BACKGROUND: Anatomic referencing in total knee arthroplasty places the femoral component flush to the anterior cortex while maintaining posterior condylar offset (PCO). The intent of this study was to evaluate how component position influences the femoral component size. METHODS: Digital surface models were created using 446 femora from an established computed tomography database. Virtual bone resections, component sizing, and component placement were performed assuming neutral (0°) flexion and neutral (3°) rotation relative to the posterior condyles. The appropriately sized femoral component, which had 2 mm of incremental size, was placed flush with the anterior cortex for optimal restoration of the PCO. Sizing and placement were repeated using 3 and 6° flexion and 0, 5, and 7° external rotation (ER). RESULTS: At 0° flexion, decreasing ER from 3 to 0° resulted in an average decreased anterior-posterior height (APH) of 1.9 mm, corresponding to a component size decrease of 1 for 88% of patients. At 7° ER, component size increased by an average of 2.5 mm, corresponding to a size increase for 80% of patients. Flexing the femoral component to 3° with ER at 3° resulted in a decrease in APH of 2.2 mm (1 size decrease in 93% of patients). At 3° flexion and 3° ER, 86% had the same component size as at 0° flexion and 0° ER. Increasing ER at 3° flexion increased APH by 1.2 mm at 5° and 3.1 mm at 7° on average, relative to 3° ER. Increasing flexion from 3 to 6° extended this effect. CONCLUSIONS: Flexion decreases the APH when the ER is held constant. The ER of the femoral component increases the APH across all tested flexion angles, causing an increase in the ideal femoral component size to maintain PCO. With anatomic referencing, alterations in femoral component positioning and subsequent changes in component size can be accounted for.

Multi-Planar Expansion of the Coronal Plane Alignment of the Knee Classification? A Computed Tomographic Study Indicates No Significant Correlation With Alignment Parameters in Other Planes.

BACKGROUND: The Coronal Plane Alignment of the Knee (CPAK) classification categorizes knee phenotypes based on constitutional limb alignment (arithmetic hip-knee-ankle angle or aHKA) and joint line obliquity (JLO). This study aimed to determine if sagittal and rotational knee alignments vary among CPAK types in order to establish whether this classification should be expanded beyond coronal plane assessment. METHODS: Coronal, sagittal, and rotational alignment measurements were made and CPAK types were calculated from computed tomographic data of 437 patients (509 knees) who underwent robotic-assisted total knee arthroplasty (TKA). Differences in femoral, tibial, and tibio-femoral angular measurements were compared across CPAK types, and correlations were made to aHKA and JLO. Nonparametric and linear regression tests were used to analyze between-type differences. RESULTS: There were no differences in tibial slope or femoral rotational measures across CPAK phenotypes. However, CPAK Type III knees had a greater tibio-femoral rotation mean difference than CPAK Type I, II, IV, and V knees (P < .05). We also found increased femoral flexion in Type I knees when compared to Type VI knees (P = .01). The aHKA had a weak correlation with femoral flexion angle, and JLO had a weak correlation with femoral posterior condylar axis to tibial antero-posterior axis angle. CONCLUSION: Few clinically important differences in sagittal and rotational alignments were found between CPAK types, indicating that CPAK phenotype has little correlation to 3-dimensional alignment characteristics. Need for an expansion of the CPAK classification beyond coronal plane alignment is not supported from these results.

Outcomes After Successful Debridement, Antibiotic, and Implant Retention Therapy for Periprosthetic Joint Infection in Total Knee Arthroplasty.

BACKGROUND: Controversy surrounds debridement, antibiotic and implant retention (DAIR) for treatment of acute periprosthetic joint infection (PJI). Data regarding DAIR's rate of infection resolution is variable with little investigation of functional outcomes. METHODS: We identified 191 DAIR cases at a single institution from 2008 to 2020. Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS-JR) and Patient Reported Outcome Measurement Information System-10 (PROMIS) scores were collected. Patient Reported Outcome Scores were obtained from 60 cases. Median follow-up (IQR) was 4.5 (2.1 to 7.6) versus 3.0 (1.2 to 5.3) years for the control group. Mean scores were compared to a cohort of uncomplicated total knee arthroplasties matched by age, body mass index, and sex using generalized linear models adjusted for follow-up duration. Kaplan-Meier survivorship curves for PJI were constructed. RESULTS: Mean Patient Reported Outcome Scores for the DAIR cohort were 57.2 ± 19.7 for KOOS-JR, 41.6 ± 7.1 for PROMIS physical health (PH), and 46.6 ± 8.7 for PROMIS mental health (MH). Mean control group values were 65.8 ± 21.0 for KOOS-JR, 44.6 ± 8.4 for PROMIS PH, and 49.2 ± 9.2 for PROMIS MH. No difference was observed in KOOS-JR (P = .83) or PROMIS MH (P = .11). PROMIS PH was lower in the DAIR cohort compared to the control group (P = .048). Median follow-up (years) for all 191 cases was 5.9 (range, 0.5 to 13.1). Survivorship (years) without subsequent operation for infection was 84% at 1, 82% at 2, and 79% at 5. CONCLUSION: Knee and MH outcomes in successful DAIR procedures were similar to uncomplicated total knee arthroplasty. DAIR's success rate was 79% in treating acute PJI at 5 years. LEVEL OF EVIDENCE: Level III.