Cruciate retaining and posterior stabilized total knee arthroplasty in severe varus osteoarthritis knee: A match-pair comparative study in an Asian population

Background Posterior stabilized (PS) total knee arthroplasty (TKA) is advocated in severe varus osteoarthritic (OA) knees as the posterior cruciate ligament posed challenges in gap balancing. However, there is scarcity in the literature to illustrate the superiority of PS TKA over cruciate retaining (CR) TKA. Our study aims to compare the outcomes between CR and PS TKAs in patients with severe varus OA knees. Methods: A retrospective review was conducted on patients who underwent primary TKA for OA knee from 2003 to 2013. Patients with OA knees of varus tibiofemoral angle ≥15 were matched into two groups (Group CR and PS) according to age, gender, and body mass index and compared in terms of clinical (tibiofemoral alignment, range of motion, and revision rate) and functional outcome (Knee Society Scoring, Oxford Knee Score, Short Form-36 Health Survey). Results: Both Group CR ( n = 56) and PS ( n = 56) had similar pre-operative scores. Both groups achieved correction of tibiofemoral alignment from median pre-operative varus of 17.6/17.0 (CR/PS) ( p = .279) to median post-operative valgus of 4.9/4.0 (CR/PS) ( p = .408). Over 24 months, both groups were comparable in achieving significant improvement in clinical and functional outcomes. No case of revision surgery was reported (median follow-up months; CR: 65, PS: 74, p = .549). Conclusion: Both CR and PS TKAs perform similarly well in severe varus OA knee up to 2 years post-operation. Further studies are warranted to assess the long-term outcome between the two implant designs.

The Insufficient Coverage of Lateral Trochlear Resection is Correlated to the Tibiofemoral Alignment Parameters in Kinematically Aligned TKA: A Retrospective Clinical Study

Background: The mismatching of the femoral component and trochlear resection surface is very common in kinematically aligned total knee arthroplasty (KA-TKA) when conventional prostheses are employed. This mismatching is mainly manifested in the insufficient coverage of the bone cut surface of the lateral trochlea. The aim of present study is to explore whether this mismatch is related to the alignment parameters of the tibiofemoral joint. Methods: 45 patients (52 knees) who underwent KA-TKA in our hospital were included. There were 16 patients (16 knees) received surgery using patient specific instrumentations, and conventional instruments with caliper and other special tools were employed in the other 29 patients (36 knees). The widths of exposed resection bone surface at the middle (MIDexposure) and distal (INFexposure) levels on the lateral trochlear were measured as dependent variables, while the hip-knee-ankle (HKA) angle, mechanical lateral distal femoral angle (mLDFA), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA) and transepicondylar axis angle (TEAA) were measured as independent variables. Correlation analysis and subsequent linear regression were conducted among the dependent variables and various alignment parameters of the tibiofemoral joint. Results: The incidence of insufficient coverage of the lateral trochlear cut bone surface was 86.5%, with MIDexposure and INFexposure being 2.3 (0-6mm) and 2.0 (0-5mm), respectively. The widths of two levels of exposed bone resection were significantly correlated to mLDFA and HKA, but were not related to TEAA. Conclusions: the insufficient coverage of trochlear resection surface in KA-TKA is negatively correlated with the degrees of valgus of the distal femoral joint line and the degrees of varus of the knee. The present study suggest that in the development of KA-specific prostheses, attention should be paid to the effects of tibiofemoral alignment parameters on the prosthetic matching of the trochlear resection surface.

Femoral Component Alignment Boundaries for Tibia First Gap Balancing using Digital Tensioning Tool

Achieving a balanced knee is a critical aspect of Total Knee Arthroplasty (TKA). Coronal and axial boundaries for femoral component placement to achieve balance however, are not well defined. Our aim is to investigate the effect of femoral component and long leg coronal and axial alignment on patient outcomes when using a tibia-first gap balancing technique.All surgeries were performed using the OMNIBotics robot-assisted TKA platform and BalanceBot device. A total of 197 patients were prospectively enrolled into this study and received TKA surgery using the OMNIBotics platform and completed 1-year KOOS outcome scores. Femoral component and tibiofemoral alignment were categorized as inliers or outliers in the coronal and axial planes. Knee Injury and Osteoarthritis Outcome Score (KOOS), and University of California at Los Angeles Activity Scale (UCLA) was collected at 1-year post-op.No significant differences were found between the KOOS subscores or UCLA outcome and femoral coronal or tibiofemoral coronal and axial alignment. Significant differences were found between the KOOS pain and sports sub-scores and femoral axial alignment (∆ = 5.4, p = 0.007, ∆ = 8.3, p = 0.03 respectively), in which outlier femoral rotation reported higher scores.Component alignment limits for improved survival and patient outcomes are a source of ongoing debate. The data presented here indicates that when utilizing a tibia-first gap balancing technique, small deviations outside of traditional ±3°alignment boundaries did not negatively affect KOOS or UCLA outcomes, indicating balance may have a stronger link to patient outcome than alignment.

Frontal Plane Tibiofemoral Alignment is Strongly Related to Compartmental Knee Joint Contact Forces and Muscle Control Strategies During Stair Ascent

Static frontal plane tibiofemoral alignment is an important factor in dynamic knee alignment and knee adduction moments (KAMs). However, little is known about the relationship between alignment and compartment contact forces or muscle control strategies. The purpose of this study was to estimate medial (MCF) and lateral (LCF) compartment knee joint contact forces and muscle forces during stair ascent using a musculoskeletal model implementing subject-specific knee alignments. Kinematic and kinetic data from 20 healthy individuals with radiographically confirmed varus or valgus knee alignments were simulated using alignment specific models to predict MCFs and LCFs. Muscle forces were determined using static optimization. Independent samples t-tests compared contact and muscle forces between groups during weight acceptance and during pushoff. The varus group exhibited increased weight acceptance peak MCFs, while the valgus group exhibited increased pushoff peak LCFs. The varus group utilized increased vasti muscle forces during weight acceptance and adductor forces during pushoff. The valgus group utilized increased abductor forces during pushoff. The alignment-dependent contact forces provide evidence of the significance of frontal plane knee alignment in healthy individuals, which may be important in considering future knee joint health. The differing muscle control strategies between alignments detail-specific neuromuscular responses to control frontal plane knee loads.

Frontal plane tibio-femoral alignment and its association with knee pain among patients with early osteoarthritis of the knee in a population presenting to a tertiary hospital in South India

<p class="abstract"><strong>Background:</strong> <span lang="EN-IN">Frontal plane knee malalignment may increase the progression of knee osteoarthritis (OA) and worsen functional capacity</span><span lang="EN-IN">.</span></p><p class="abstract"><strong>Methods:</strong> <span lang="EN-IN">In our study, the aim was to find the correlation of frontal plane tibiofemoral alignment with knee pain in early OA knee patients. After meeting the inclusion and exclusion criteria, 195 patients with 314 knees (104 females, 91 males) were studied. Clinical and radiological measurements of frontal plane tibiofemoral alignment, using landmark of hip, knee, and ankle, compared with knee pain</span>.<strong></strong></p><p class="abstract"><strong>Results:</strong> <span lang="EN-IN">The accepted Statistical significance was p&lt;0.05. Patients with 130 knees (41%) were normal alignment, and 184 knees (59%) were abnormal alignment. The mean±SD age in our study was 54.6±8.9 years. The mean±SD BMI in our study to be 25.86±1.96. Mean±SD Q-angle in patients with normal and abnormal alignment was 14.76±1.54 and 14.63±1.9 respectively. There is statistically no significant correlation between BMI and VAS score (r=0.054, p=0.344). Means±SD of mLDFA, mMPTA, mTFA, aTFA, and JOA were 88.86±2.73, 84.96±3.00, 5.96±4.01, 4.55±3.67, and 2.37±1.88 respectively. JOA and mTFA had statistically significant weak positive correlation with VAS (knee pain) score, (r=0.281) (p=0.000) and (r=0.236) (p=0.000) respectively. The rest of the angles were not had statistically significant correlation with VAS score. The mTFA had statistically significant weak positive correlation with all the angles. We found that Frontal plane tibiofemoral alignment correlates with knee pain in patients with early OA</span><span lang="EN-IN">. </span></p><p class="abstract"><strong>Conclusions:</strong> <span lang="EN-IN">The mTFA may be considered one important criterion in designing treatment and planning surgery for patients with primary osteoarthritis. The Q angle acts as a good alternative clinical tool in assessing frontal plane alignment. BMI was not correlating with knee pain (VAS score)</span><span lang="EN-IN">.</span></p>