Medial Knee Osteoarthritis Research Articles

Association between varus thrust and foot alignment and flexibility in knee osteoarthritis.

Varus thrust (VT) is a frequently reported abnormal gait pattern in patients with medial knee osteoarthritis (KOA). VT is important to prevent KOA progression. However, there is no consensus on the relationship between VT and foot alignment and flexibility, although it has been reported that patients with KOA have pronated foot. In this study, we examined the relationship between VT, foot alignment, and flexibility in patients with KOA. Twenty patients with unilateral KOA were included in this study (mean age: 71.5 ± 4.7 years). KOA severity ranged from grade III (8 patients) to grade IV (12 patients) based on the Kellgren-Lawrence classification. Gait analysis using inertial sensors was performed to determine the difference between the VT of KOA side and the contralateral side without symptoms. The correlations between VT, foot alignment, and flexibility were also analyzed. VT was significantly greater on the side with KOA than on the contralateral side without KOA (d = 1.09, p = .002). VT was not significantly correlated with foot alignment but was significantly correlated with the arch stiffness index, which indicates foot flexibility (r = 0.642, p = .003). This study suggests that foot flexibility may play a more significant role than foot alignment in addressing VT in patients with KOA. When performing physical therapy for VT, evaluating foot flexibility in addition to foot alignment may help reduce this condition. Further studies with larger sample sizes and more detailed statistical analyses are needed to validate these findings.

Inpatient cost comparison of total and unicompartmental knee arthroplasty in patients with medial compartmental osteoarthritis using time-driven activity-based costing.

Using time-driven activity-based costing (TDABC), we sought to compare the total facility costs, comprising supply and personnel costs during the episode of care for the index procedure, in patients with isolated medial compartmental knee osteoarthritis (OA) undergoing unicompartmental knee arthroplasty (UKA) versus total knee arthroplasty (TKA). We conducted a retrospective analysis of 100 UKAs and 100 TKAs from 2019 to 2022. From a larger sample of 4899 TKAs and 137 UKAs, patients with isolated medial OA (Kellgren-Lawrence Grade <2 in other compartments) were radiographically identified. Demographic data included age, sex and body mass index, with comorbidities controlled using the Charlson comorbidity index. Facility costs were calculated using TDABC and standardized in cost units (CUs), a metric for comparing costs across procedures. Multiple regression analysis was used to assess the independent effect of TKA versus UKA on facility costs. TKA patients had similar operative times (TKA vs. UKA: 1.01×, p = 0.783) and supply costs (1.00×, p = 0.866), where 'x' denotes the relative cost ratio. However, TKA was associated with higher personnel costs (260.0 vs. 222.5 CUs [1.17×], p < 0.001) and total facility costs, both including (706.3 vs. 667.5 CUs [1.06×], p = 0.007) and excluding implants (353.8 vs. 312.5 CUs [1.13×], p < 0.001). Adjusted for demographics and comorbidities, TKA had increased facility costs, including (32.2 CUs, 95% confidence interval [CI]: 2.9-61.5, p = 0.031) and excluding implants (37.8 CUs, 95% CI: 15.2-60.3, p = 0.001). TDABC analysis revealed higher total facility costs for the index procedure in TKA, suggesting UKA may be a cost-saving alternative for isolated medial compartment knee OA. Level III, retrospective comparative study.

Association of Flat Feet with Knee Moments and Western Ontario and McMaster Universities Arthritis Index in Knee Osteoarthritis

Introduction: Flat feet are prevalent among individuals with medial compartment knee osteoarthritis (KOA), showing a correlation with elevated knee pain and cartilage degeneration. This study investigates the relationship between calcaneal eversion angle (CEA) and medial longitudinal arch angle (MLAA) with knee kinetics and pain. Materials and Methods: This analytical observational study included 30 volunteers with moderate KOA. The Vicon motion analysis system and two synchronized force plates were employed to capture level walking and the static standing position to measure CEA and MLAA. The study assessed the first and second peaks of the knee adduction moment, knee adduction moment impulse, peak knee flexion moment, and the peak knee flexion angle at heel strike (PKFA-HS). The Western Ontario and McMaster Universities arthritis index (WOMAC) pain and physical function were evaluated. Results: A significant positive correlation was found between CEA and the knee pain sub-score (Pearson correlation [PC]=0.446, P=0.011) and WOMAC total score (PC=0.363, P=0.049). Additionally, a significant negative correlation was observed between CEA and peak knee flexion moment/PKFA-HS (PC=-0.418, P=0.022, and PC=-0.479, P=0.001, respectively). The results also indicated a negative significant correlation between MLAA and WOMAC pain sub-score (PC=-0.389, P=0.034). Conclusion: Increased CEA and decreased MLAA are associated with elevated WOMAC pain sub-score and decreased PKFA-HS in individuals with moderate KOA. Addressing flat feet should be considered in KOA management to enhance pain relief and functional outcomes

Toe-in and toe-out gait retraining interventions for individuals with knee osteoarthritis trial: A pilot randomised clinical trial

BackgroundGait retraining, through altering foot progression angle, has the potential to reduce pain and offload the medial tibiofemoral compartment in people with knee osteoarthritis. This pilot study aimed to evaluate the feasibility of toe-in and toe-out gait retraining on self-reported pain and physical function, and proxy measures of medial knee load, in individuals with medial knee osteoarthritis. MethodsTwenty participants with symptomatic medial knee osteoarthritis were randomly allocated to receive either toe-in or toe-out gait retraining for six-weeks, consisting of weekly clinician-supervised sessions and ≥ 30 min of daily self-practice. Feedback was guided by wearable sensors and a pressure-sensitive mat. Primary outcomes included recruitment rate, data completeness, adverse events, adherence, achievability, and intervention acceptability. Secondary outcomes were proxy measures of medial knee load, self-reported pain and physical function. Differences in feasibility and self-reported outcomes were interpreted via sample t-test using intention-to-treat analysis. The effect of the intervention group on knee biomechanics was evaluated using linear mixed modelling. FindingsRecruitment was acceptable (n = 4/month) with excellent data completeness (93 %) and attendance (82 %). Acceptability was moderate and similar between groups. There were no differences in average knee pain and physical function between groups over time, and both groups reduced maximum knee pain following the intervention (35 % improvement, p = 0.012). There were no differences in biomechanical outcomes between groups over time. InterpretationToe-in and toe-out gait retraining is feasible and improves pain in people with knee osteoarthritis. A full-scale randomised clinical trial is warranted and should consider individualising the intervention.

Population-based in silico modeling of anatomical shape variation of the knee and its impact on joint loading in knee osteoarthritis.

Anatomical knee joint features and osteoarthritis (OA) severity are associated, however confirming causals link to altered knee loading is challenging. This study leverages statistical shape models (SSM) to investigate the relationship between joint shape/alignment and knee loading during gait in knee OA(KOA) patients to understand their contribution to elevated medial knee loading in OA. Musculoskeletal (MSK) models were created for the mean as well as the first eightSSM principal modes of variation (-3,-2,-1, +1, +2, +3 standard deviations for each mode) and used as input to a MSK modeling framework. Using an identical KOA gait pattern (i.e., joint kinematics and ground reaction forces), we ran simulations for each MSK model and evaluated medial compartment loading magnitude and contact distribution at the instant of first and second peak of knee joint loading. An increase in external rotation, posterior tibia translation and a decrease in medial joint space and medial femoral condylar size predisposed the medial compartment knee joint to overloading during gait. This was coupled with an anterior and medial shift in contact location with increasing external rotated tibial position and increasing posterior tibial translation with respect to the femur. Next, results also highlighted a posterior shift of the medial compartment loading location with decreasing medial joint space. This study provides important population-based insights on how knee shape and alignment predispose individuals with KOA to elevated medial compartmental knee loading. This information can be crucial in assessing the risk for medial KOA development and progression.

Exercise and footwear in medial knee osteoarthritis: a randomized controlled trial comparing flat flexible footwear to stable supportive shoes

Abstract Objective This randomized controlled trial (RCT) investigated whether adding daily use of flat flexible footwear (FFF) to a strengthening and aerobic exercise programme improved short- and longer-term outcomes compared to adding stable supportive shoes (SSS) in people with medial tibiofemoral osteoarthritis (OA). Methods Participants (n = 97) with medial tibiofemoral OA were randomly assigned (1:1) to FFF (n = 50) or SSS (n = 47) group. Participants in both group received a 9-month intervention (3 months supervised followed by 6 months unsupervised exercise). The primary outcome was change in knee pain on walking at 3 months measured using a 11-point numeric rating scale (NRS). Secondary outcomes included change from baseline to 3 and 9 months in severity of knee pain overall (NRS), physical function (WOMAC subscale), habitual physical activity level (PASE), quality of life (QoL) (EQ-5D-5L), and markers of inflammation (Effusion- and Hoffa-synovitis) and structural disease progression (bone marrow lesions (BMLs)). Results There were no significant differences between the groups in the change in pain on walking (between-group difference, -0.67 [95% CI, -1.62 to 0.29]) at 3 months. Knee pain on walking and overall knee pain significantly decreased in both groups at 3 months and 9 months. Physical function and QoL improved in both groups at 3 months and at 9 months. We found no between-group differences in any secondary outcome at any time. Conclusions FFF added to exercise therapy did not provide additional better symptom- nor structure-modification benefit compared to conventional SSS and exercise in people with medial tibiofemoral OA. Clinical trial registration number ClinicalTrials.gov (NCT03796832)

Femoral cartilage defects initiate from medial meniscus extrusion or tibial cartilage lesions and expand in knee osteoarthritis as revealed by 3D MRI analysis

Knee osteoarthritis is characterized by articular cartilage wear, with its morphological progression not fully understood. This study aimed to elucidate factors contributing to femoral cartilage defects and their expansion in medial knee osteoarthritis, using a novel approach analyzing cross-sectional MRI data arranged by disease severity. From a cohort of 277 women in the Kanagawa Knee Study, we selected 17 knees that showed a cartilage area ratio < 0.99 in the posteromedial femoral cartilage region as the subjects for this study. The morphological relationships between femoral cartilage defects and menisci, as well as between femoral cartilage defects and tibial cartilage lesions, were investigated. Among subjects aged 30 to 79 years, the proportion was significantly higher in the 70–79 age group. In 11 cases, the outer edge of the cartilage defect was observed to coincide with the inner edge of the medial meniscus. Tibial cartilage lesions corresponded to femoral cartilage defects in 15 cases. Our 3D MRI analysis demonstrated that femoral cartilage defects were initially caused by either medial meniscus extrusion or kissing tibial cartilage lesions, with subsequent expansion of these defects resulting from the combined effects of ongoing medial meniscus extrusion and progressive tibial cartilage degeneration.Trial registration: UMIN, UMIN000032826; September 1, 2018.

Influencing factors analysis of asymmetry in knee adduction moment among patients with unilateral knee osteoarthritis

BackgroundThe knee adduction moment(KAM) of both lower limbs in patients with unilateral knee osteoarthritis(KOA) exhibits asymmetry during walking, but the factors influencing this asymmetry remain unclear. This study aimed to explore the influencing factors of KAM asymmetry in patients with unilateral KOA.MethodsA total of 148 patients with unilateral medial compartment KOA were selected for this retrospective study, and general data such as gender, age, and duration of disease were collected. The hip-knee-ankle (HKA) angle, degree of pain, and knee-extension muscle strength on the affected side were assessed through radiographic outcomes, the visual analog scale(VAS), and the Biodex isokinetic system. The peak KAM of both lower limbs was analyzed using a BTS motion-capture system and force platform. The asymmetry index(ASI) of KAM was calculated, and the patients were further categorized into the KAM symmetry group(ASI value ≤ 10%) and the KAM asymmetry group(ASI value>10%).Binary logistic regression analysis was employed to analyze the factors influencing the asymmetry of KAM.Results90 patients were categorized into the KAM asymmetry group, representing 60.8% of the cohort. A significant difference in the ASI value of KAM was observed between the two groups. Correlation analysis identified nine factors, including sex, age, and BMI, that were positively correlated with the ASI value of KAM. In contrast, knee-extension muscle strength and per-capita monthly household income were negatively correlated with the ASI value of KAM. Regression analysis revealed that being female(OR = 1.752), older age(OR = 2.472), increased BMI(OR = 1.535), larger varus angle(OR = 3.965), higher VAS score(OR = 2.617), Kellgren-Lawrence(K-L) grade IV(OR = 4.474), history of knee joint trauma(OR = 5.684), and living in a rural location(OR = 1.554) increased the risk of KAM asymmetry. Conversely, increased knee-extension muscle strength(OR = 0.758) and a per-capita monthly household income of 3000 ~ 6000 yuan(OR = 0.814) decreased the risk of KAM asymmetry.ConclusionFemale gender, older age, increased BMI, larger varus angle, higher VAS score, K-L grade IV, history of knee joint trauma, and living in a rural location are identified as risk factors for KAM asymmetry. Conversely, increased knee-extension muscle strength and a per-capita monthly household income of 3000 ~ 6000 yuan serve as protective factors against this asymmetry.

The efficacy of patellar denervation on prognosis and kneeling capacity after unicompartmental knee arthroplasty: a randomized clinical trial.

The aim of this study was to investigate the effect of patellar denervation (PD) on pain, function and ability to kneel after unicompartmental knee arthroplasty (UKA). Patients with medial knee osteoarthritis who underwent UKA were prospectively selected. Patients were randomly divided into PD and non-PD groups based on whether patellar denervation was performed. Clinical assessment was performed using the Hospital for Special Surgery (HSS) knee score, Kujiala score, visual analogue scale (VAS) and forgotten joint score (FJS-12), as well as postoperative complications were recorded. The patients' postoperative self-perception and actual ability to perform different kneeling positions were assessed in the two groups. UKA patients treated with PD achieved better Kujiala scores and FJS-12 scores, reduced anterior knee pain and improved kneeling ability postoperatively, validating the effectiveness of PD in UKA. Perception and actual performance of kneeling remained mismatched in PD patients, but performance during different kneeling activities was generally better than in non-PD patients. Clinical Trial Registration: ChiCTR1900025669. Patellar denervation can safely and effectively improve patellofemoral joint function, pain and kneeling ability in the early postoperative period after UKA.

Comparing Sagittal-Plane Biomechanics of Drop Jump Landing in Athletes With and Without Knee Osteoarthritis 2-Year Post-Anterior Cruciate Ligament Reconstruction.

The study aimed to determine differences in sagittal-plane joint biomechanics between athletes with and without knee osteoarthritis (OA) during drop vertical jump 2years after anterior cruciate ligament reconstruction (ACLR). Forty-one athletes with ACLR completed motion analysis testing during drop vertical jump from 30cm. Sagittal-plane peak joint angles and moments and joint contributions to total support moment (TSM) were calculated during first landing. Medial compartment knee OA of the reconstructed knee was evaluated using Kellgren-Lawrencescores (ACLR group: Kellgren-Lawrence <2; ACLR-OA group: Kellgren-Lawrence ≥2). The ACLR-OA group (n = 13) had higher hip and lower knee contributions in the surgical limb than the ACLR group and their nonsurgical limb. Further, the ACLR-OA group had higher peak hip extension moment than the ACLR group (P = .024). The ACLR-OA group had significantly lower peak knee extension and ankle plantar flexion moments and TSM (P ≤ .032) than ACLR group. The ACLR-OA group landed with increased hip extension moment, decreased knee extension and ankle plantar flexion moments and TSM, and decreased knee and increased hip contributions to TSM compared with ACLR group. The ACLR-OA group may have adopted movement patterns to decrease knee load and compensated by shifting the load to the hip. Clinicians may incorporate tailored rehabilitation programs that mitigate the decreased knee load to minimize the risk of knee OA after ACLR.

Knee

The October 2024 Knee Roundup360 looks at: Managing the unexpected: treatment of intraoperative medial collateral ligament injuries; Identifying subgroups of patients that may benefit from robotic arm-assisted total knee arthroplasty: secondary analysis of data from a randomized controlled trial; Cost-effectiveness of enoxaparin versus aspirin in the prevention of venous thromboembolism after total hip or knee arthroplasty: an analysis from the CRISTAL cluster-randomized trial; Cartilage regeneration and long-term survival in medial knee osteoarthritis patients treated with high tibial osteotomy and osteochondral autologous transfer system; Treatment of chronic and complex meniscal tears with arthroscopic meniscus repair augmented with collagen matrix wrapping: failure rate and functional outcomes; Long-term outcomes of multiligament knee injuries in American football players.

Simultaneous bilateral open wedge high tibial osteotomy versus simultaneous bilateral unicompartmental knee arthroplasty in the treatment of bilateral medial knee osteoarthritis: a retrospective study of an average three-year follow-up

ObjectiveThere is growing evidence that simultaneous bilateral open wedge high tibial osteotomy(SBOWHTO) and simultaneous bilateral unicompartmental knee arthroplasty(SBUKA) is an effective surgical treatment for bilateral medial knee osteoarthritis (MKOA). However, which intervention is more beneficial for bilateral MKOA patients remains unknown. Therefore, the aim of this study was to compare the effectiveness of these two strategies through early clinical outcomes, complication rates, and prosthetic survival.MethodsThe clinical data of 60 patients with bilateral MKOA admitted to the Affiliated Hospital of Qingdao University from January 2018 to December 2022 were retrospectively analyzed, and they were divided into SBOWHTO group (n = 28) and SBUKA group (n = 32) according to different treatment methods. Clinical relevant indexes, Hospital for Special Surgery (HSS) score, Knee Society Knee (KSS) score, range of motion(ROM), postoperative complications and prosthetic survival rate were compared between the two groups.ResultsPatients in the SBOWHTO group were followed up for 27 to 50 months, with an average of (37.18 ± 6.84) months. Patients in the SBUKA group were followed up for 24 to 59 months, with an average of (39.38 ± 9.74) months. There were no significant differences in postoperative KSS, HSS and ROM between SBOWHTO group and SBUKA group (p > 0.05). There was no significant difference in complication rate between the two groups (p = 0.721). There was no significant difference in prosthetic survival rate (p = 0.622) and prosthetic survival curve (χ2 = 0.546, p = 0.46) between the two groups.ConclusionsThis study compared early clinical outcomes, complication rates, and prosthesis retention rates after SBOWHTO and SBUKA, and found that the early clinical benefits of SBOWHTO and SBUKA were comparable in patients with bilateral MKOA.

The Effectiveness of Massage on Pain, External Knee Adduction Moment, and Muscle Co-contraction in Individuals with Medial Compartment Knee Osteoarthritis

BackgroundThe pain, external knee adduction moment (EKAM), and muscle co-contraction are increased in knee osteoarthritis (KOA). Massage therapy decreases pain in KOA, yet KOA is a mechanical disease and biomechanical changes need to be investigated as well. Therefore, the current study aims to investigate the effectiveness of massage on these outcomes in individuals with medial KOA. MethodsA cohort of fifteen participants with confirmed medial compartment KOA (2 males, 13 females, age: 61.33 (6.16) years; height: 1.62 (0.06) m; mass: 65.39 (4.04) kg; BMI: 24.74 (4.04) kg/m2) was given a six-week massage. Outcomes assessed pre- and post-intervention were: Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, temporal-spatial variables, knee joint kinematics and kinetics in sagittal, frontal, and transverse planes, vertical ground reaction force (GRF), and knee antagonist muscle co-contraction during gait. The paired t-test were used for statistical analysis. ResultsFifteen participants completed the study. Significant improvements were observed in WOMAC scores (pain, stiffness, function, and total), walking speed, step length, 1st peak GRF, sagittal plane knee joint range of motion during stance, and medial muscle co-contraction in early and mid-stance (p<0.05). However, no significant change was found in EKAM and knee adduction angular impulse (KAAI) (p>0.05). ConclusionMassage therapy, as a stand-alone treatment, reduces pain, improves function, and decreases medial muscle co-contraction in individuals with medial KOA. Although EKAM did not change, the results suggest a reduction in medial muscle co-contraction might be a mechanism by which pain is improved.

Cemented versus cementless Oxford unicompartmental knee arthroplasty for the treatment of medial knee osteoarthritis: an updated systematic review and meta-analysis.

This meta-analysis sought to compare the efficacy of cemented versus cementless Oxford unicompartmental knee arthroplasty(UKA) for the treatment of medial knee osteoarthritis. A comprehensive search of the following databases was conducted: Pubmed, The Cochrane Library, China National Knowledge Infrastructure (CNKI), Embase, the Web of Science, and MEDLINE. The objective was to identify literature comparing cemented versus cementless Oxford unicompartmental knee arthroplasty for the treatment of medial knee osteoarthritis. Duplicate literature, low-quality literature, literature with incompatible observations, and literature for which the full text was not available were excluded. Two independent researchers employed the Cochrane Risk Assessment Tool and the Newcastle-Ottawa Scale (NOS) to evaluate the quality of the included literature. The data then were extracted and subsequently meta-analyzed using RevMan 5.4. A total of 12 papers were included in the analysis, encompassing a cumulative of 2558 cumulative cases. Of these, 1258 were cemented and 1300 were cementless. A meta-analysis was conducted to compare the outcomes of cemented versus cementless Oxford UKA. The Oxford UKA group exhibited a significantly longer surgery time than the cementless Oxford UKA group [mean difference (MD) = 9.91, 95% confidence interval (CI) (7.64,12.17)]. Additionally, the cemented Oxford UKA group demonstrated a significantly lower knee OKS score compared to the cementless Oxford UKA group. The mean difference (MD) was - 1.58 (95% CI: -2.30, -0.86), indicating a significantly lower score for the cemented Oxford UKA group. Similarly, the mean difference (MD) was - 1.8 for the knee KSS clinical score, indicating a significantly lower score for the cemented Oxford UKA group. The results demonstrated that the knee KSS functional score was significantly lower in the cemented Oxford UKA group than in the cementless Oxford UKA group [MD=-1.72, 95% CI (-3.26, -0.37)]. 95% CI (-3.27,-0.17)], the cemented Oxford UKA group exhibited a significantly higher incidence of radiolucent lines around the prosthesis than the cementless Oxford UKA group [ratio of ratios (OR) = 3.62, 95% CI (1.08,12.13)]. The revision rate was significantly higher in the cemented Oxford UKA group than in the cementless Oxford UKA group [OR = 2.22, 95% CI (1.40,3.53)]. However, no significant difference was observed between the two groups in terms of reoperation rate, five-year prosthesis survival rate, and complication rate. The findings indicated that, in comparison to cemented Oxford UKA, cementless Oxford UKA resulted in a reduction in surgical time, an improvement in knee OKS score, KSS clinical score, and KSS functional score, and a decrease in the incidence of periprosthetic radiolucent lines and the rate of revisions.

Medial open wedge high tibial osteotomy is a viable option in young patients with advanced arthritis in a long-term follow-up.

This study aimed to evaluate the long-term outcomes of medial open wedge high tibial osteotomy (MOWHTO) as a treatment option for advanced medial compartment knee osteoarthritis (OA) Kellgren-Lawrence (K-L) III and IV. Patients with severe medial compartment arthritis, who underwent MOWHTO with locking plate between 2003 and 2015, were retrospectively reviewed. A locking plate for the osteotomy was utilized. Preoperative and postoperative patients' evaluation was performed using the International Knee Documentation Committee Score (IKDC), the Oxford Knee Score (OKS), the Knee Injury Osteoarthritis Outcome Score (KOOS) and the Short Form-12 Score (SF-12). Standardized standing whole-limb X-rays were taken to evaluate the mechanical tibiofemoral angle (mTFA) and proximal medial tibial angle (PMTA), and the severity of OA. A total of 32 patients, 35 knees (27 males, five females) of which 21 were classified as K-L Grade III and 14 as K-L Grade IV, and mean age 47.1 ± 9.17 years old, who were followed for 13.6 years (range 7-20 years), were included in the study. During the follow-up period, three knees required conversion to total knee replacement (91.5% survival rate). All clinical outcome scores (KOOS, OKS, IKDC and SF-12) showed a significant improvement compared to preoperative status (p < 0.05). Preoperative mTFA and PMTA were significantly corrected immediately after surgery and retained this improvement at the last follow-up. MOWHTO with a locking plate is an effective method to treat severe medial compartments. Clinical and radiological results are satisfactory and the survival rate is 91.5%, at a mean follow-up of 13.6 years after the procedure. Level IV.

The influence of knee position during static calibration trials on evaluation of knee loading during gait in individual with medial knee osteoarthritis

Quantitative three-dimensional gait analysis has been used to evaluate the loading at the knee (i.e. external knee adduction moment, EKAM) during level ground walking in individuals with knee osteoarthritis (OA). The magnitude of EKAM can be influenced by some factors, such as knee marker position and foot placement angles in static calibration trials, which may lead to inaccurate functional assessments and intervention planning. This study aimed to clarify the effects of knee position during static calibration trials on the evaluation of knee loading during gait in individuals with medial knee OA. Seventeen individuals with medial knee OA completed three different static standing trials; (1) knee flexed at 0 degrees, (2) knee flexed at 15 degrees, and (3) knee flexed at 30 degrees before walking at their self-selected speed. A sixteen-camera three-dimensional VICON gait analysis system with four AMTI force platforms was used to collect the EKAM, knee adduction angular impulse (KAAI), knee joint center (KJC), and other knee kinematic and kinetic variables during gait. A repeated measures ANOVA was used to investigate the differences between conditions. The 1st peak of EKAM, the 1st peak EKAM arm, KAAI, and knee extension moment were significantly increased at the 15-degree and 30-degree conditions in comparison with the 0-degree condition (P < 0.05). Additionally, the knee flexion moment and knee external rotation moment were significantly reduced at the 15-degree and 30-degree conditions in comparison with the 0-degree condition (P < 0.05). All biomechanical variables were influenced by the localization of the KJC during static calibration trials. The changes in knee position during static trials significantly affected the 1st peak EKAM, KAAI, and other knee kinematics and kinetics variables during gait. Therefore, future studies should consider keeping the participants’ knees in a consistent position during static trials between visits, as the variations in knee position could mask or exaggerate the differences between groups and interventions.

Medial opening wedge high tibial osteotomy performs similarly irrespective of body mass index.

This study investigates the effect of the body mass index (BMI) on the early (2 years) to midterm (5 years) results of medial opening wedge high tibial osteotomy (MOWHTO). A prospectively maintained single-centre database of 1138 knee osteotomies, between 2002 and2022, was retrospectively reviewed. Adult patients who underwent MOWHTO for symptomatic unicompartmental medial knee osteoarthritis (OA), with varus knee malalignment, having failed conservative management, were included. Patients were categorized into threegroups according to their BMI as per the classification from the National Institute for Health and Care Excellence (NICE): the healthy weight (HW) group (BMI of 18.5-24.9 kg/m2), the overweight (OW) (BMI of 25-29.9 kg/m2), and the obesity (OB) group (BMI ≥ 30 kg/m2). Multiple patient-reported outcome measures (n = 6) were recorded preoperatively and at 2 and 5 years postoperatively. Deformity analysis was undertaken preoperatively and postoperatively. The relative risk (RR) of the complications between the HW, OWand OB groups was calculated. The rate of conversion to arthroplasty, and 5and 10 years survivorship were recorded, as well as the hazard ratio (HR) of BMI on survivorship. A total of 574 cases were included in the study: the HW group (n = 96), the OW group (n = 233)and the OB group (n = 245), with a mean BMI of 23 ± 1.5 kg/m2, 27.4 ± 1.4 kg/m2 and 34.4 ± 3.8 kg/m2, respectively. The mean follow-up was 13.3 years (4.8-20.3). The mean mechanical tibiofemoral angle corrections were in the HW group: 7.1 ± 3°, OW group: 6.6 ± 3.5°and OB group: 7.1 ± 3.8°, with no intergroup significant difference (p = n.s.). Clinically, despite lower preoperative scores in the OW and OB groups, no difference was observed postoperatively amongst the three groups. The overall complication rate was 12.5% in the HW group, 6.8% in the OW group, and 9.8% in the OB group. There was no significant difference in the RR of complications between the HW and OW groups (RR = 0.6, 95% confidence interval [CI] = 0.3-1.3)(p = 0.2), and the HW and OB groups (RR = 0.8; 95% CI = 0.3-2.2)(p = 0.7). There was no overall significant difference in survival outcomes based on the BMI between the threegroups (p = 0.4). The HR of conversion to arthroplasty between the HW and OW groups was 1.4 [95% CI = 0.6-3.5](p = 0.5)and between the HW and OB groups was 1.8 [95% CI = 0.8-4.4] (p = 0.2). BMI has no significant effect on either the radiological corrections, clinical outcomes, complicationsor survivorship of MOWHTO at short- to medium-term follow-up. No specific cutoff point for BMI can be recommended as a contraindication to MOWHTO. Level IV, Retrospective cohort study.

Association Between Overhang of the Posterior Femoral Condyle and Restricted Postoperative Knee Flexion Related to Patient-Reported Stiffness in Medial-Pivot Total Knee Arthroplasty

BackgroundThe primary aim of this study was to investigate the association between the posterior longitudinal overhang in the femoral condyle (PLOF) in medial-pivot total knee arthroplasty (TKA) and a change in knee flexion angle (change in flexion). MethodsThis retrospective cohort study included 148 knees undergoing medial-pivot TKA for medial knee osteoarthritis. The primary outcome was the change in flexion (c-flexion) preoperatively and 1-year postoperatively. The component positions were evaluated using 3-dimensional measurements, where the PLOF was measured for each medial and lateral femoral condyle. The secondary outcome was the Western Ontario and McMaster Universities Osteoarthritis Index scores taken preoperatively and 2 years postoperatively. A multivariate regression analysis was performed to determine predictors of c-flexion and risk factors for negative c-flexion (less than 0°). Furthermore, a receiver operating characteristic curve was utilized to determine the threshold for negative c-flexion. ResultsThe mean c-flexion was −3.2° ± 8.7, and lateral PLOF was significantly associated with c-flexion (β = −0.52; P < 0.001). Larger preoperative flexion angles (odds ratio, 1.10; P < 0.001) and larger lateral PLOF (odds ratio, 1.69; P = 0.001) were risk factors for negative c-flexion, with thresholds of 129° and 1.1 mm, respectively (sensitivity, 0.79; specificity, 0.72). Additionally, patients who had negative c-flexion (n = 91) demonstrated less improvement in preoperative and 2-year postoperative Western Ontario and McMaster Universities Osteoarthritis Index stiffness subscores than patients who had positive c-flexion (0° or more; n = 57) (P = 0.01). ConclusionsA larger lateral PLOF was associated with decreased and negative c-flexion after medial-pivot TKA. Patients who had negative c-flexion demonstrated less improvement in knee stiffness. Surgical strategies aimed at minimizing lateral PLOF may enhance postoperative knee flexion and overall patient outcomes in medial-pivot TKA.

Influence of Increased Joint Line Obliquity on Survivorship After Lateral Closing-Wedge High Tibial Osteotomy

Background: Although high tibial osteotomy (HTO) has emerged as a powerful intervention for treating symptomatic medial osteoarthritis and varus malalignment, it can result in an increase in knee joint line obliquity (KJLO) in the frontal plane. Limited current evidence hinders understanding of the effect of increased KJLO on HTO survivorship. Purpose: To investigate the influence of KJLO and other potential risk factors on the survivorship of lateral closing-wedge HTO. Study Design: Cohort study; Level of evidence, 3. Methods: Patients with symptomatic medial knee osteoarthritis and varus malalignment treated with lateral closing-wedge HTO at a single hospital were screened with a minimum follow-up of 5 years. HTO survival rate was assessed using Kaplan-Meier survival analysis. The influence of postoperative increased KJLO (medial proximal tibial angle ≥95°), age (≥55 years), sex (female), preoperative malalignment (hip-knee-ankle angle ≥10° of varus), postoperative untargeted alignment (hip-knee-ankle angle <2° or >6° of valgus), and preoperative osteoarthritis severity (Kellgren-Lawrence grade ≥3) on survivorship of HTO was evaluated using Cox regression analysis. A failure of HTO was defined as a conversion to total knee arthroplasty (TKA). Results: A total of 410 patients (463 knees) were included, with a mean follow-up of 13.0 years (range, 5.0-18.1 years) and a mean survival time of 11.2 years (range, 1.2-18.1 years) for patients who reached the endpoint of TKA. HTO survival rates at 5, 10, and 15 years postoperatively were 91%, 78%, and 60%, respectively. Multivariate Cox regression analysis showed no significant difference in survivorship between patients with increased KJLO and those with acceptable KJLO (178 vs 285 knees; hazard ratio [HR], 0.8; 95% CI, 0.6-1.1; P = .148), with no significant between-group difference observed in the mean follow-up length (12.9 ± 3.0 years vs 13.1 ± 3.3 years; P = .105). Female sex (HR, 2.0; P < .001) and postoperative untargeted alignment (HR, 1.6; P = .003) were risk factors for a conversion to TKA. Conclusion: Increased postoperative KJLO (medial proximal tibial angle ≥95°) had no significant influence on the survivorship of lateral closing-wedge HTO. Men demonstrated superior survival outcomes compared with women, and it was important to achieve a targeted postoperative alignment (HKA 2°-6° of valgus) to ensure favorable HTO survivorship.

The Traditional Intramedullary Axis Underestimates the Medial Tibial Slope Compared to Transmalleolar Sagittal Axis in Image-based Robotic-Assisted Unicompartimental Knee Arthroplasty.

The medial unicompartmental knee arthroplasty (mUKA) has been recognized as an excellent treatment for medial knee osteoarthritis. The posterior tibial slope (PTS) is measured radiographically with the intramedullary axis (IMA) to the tibial baseplate on the sagittal plane radiograph. However, in most computer-navigated or robotic mUKAs, the PTS is set from a transmalleolar axis (TMA).The PTS difference was evaluatedbetween the sagittal TMA and the sagittal IMA of patients undergoing a CT-based primary robotic-assisted mUKA.We retrospectively reviewed the preoperative computed tomography (CT) scans taken according to the MAKO system protocol (Stryker) of 67 patients undergoing mUKAs. We measured the angular difference between the IMA and the TMA in the sagittal plane.Using the TMA to set the PTS the estimation of the slope of the medial tibial plateau would increase by an average of 1.9 ± 3.2 degreescompared to the IMA. Furthermore, in nineknees, PTS was decreased.Tibial components implanted with the help of a CT scan-based preoperative planning MAKO will show an average of 1.9 degrees more than those measured on sagittal radiographs potentially of concern for knee kinematics. A universal language is needed to standardize the slope calculation and the respective reference axis used.