Compartment Of Knee Research Articles

Quantifying Asymmetry Between Medial and Lateral Compartment Knee Loading Forces Using Acoustic Emissions.

Osteoarthritis is the most common type of knee arthritis that can be affected by excessive and compressive loads and can affect one or more compartments of the knee: medial, lateral, and patellofemoral. The medial compartment tends to be the most vulnerable to injuries and research suggests that a better understanding of the medial to lateral load distribution conditions could provide insights to the quantitative usage of knee compartments in activities of daily life. Prior to study in an osteoarthritic clinical population which may present with various complicating anatomical and physiological changes, we investigate knee acoustical emissions of able-bodied individuals during a varying width squat exercise which simulates loading asymmetries that would typically be seen in this clinical population. To that end, we present a novel method to quantify the directional bias of asymmetry between the medial and lateral compartment knee joint load in healthy individuals by recording knee acoustical emissions and analyzing them using a deep neural network in a subject independent model. We placed four miniature contact microphones on the medial and lateral sides of the patella on both the left and right leg. We compared the handcrafted audio features with the automated features extracted from the convolutional autoencoder which is an unsupervised model that learns the comprehensive representation of the input to determine whether these automated features can better represent the signal's characteristic in regard to the structural asymmetry of the knee joint. The input to the convolutional auto encoder (CAE) is a time-frequency representation and different types of these images such as spectrogram and scalogram are compared. We alsocompared the multi-sensor fusion approach with the performance of a single sensor to determine the robustness of using multiple sensors. Using a representation learning based approach, we developed a subject independent classification model capable of classifying the asymmetry of the medial and lateral joint load across subjects (accuracy = 83%). The result indicates that wavelet coherence which is the time-frequency correlation of two signals using a wavelet transform yields the best accuracy. These findings suggest that acoustic signals could potentially quantify the direction of medial to lateral load distribution which would broaden the implications for wearable sensing technology for monitoring cartilage health and factors responsible for cartilage breakdown and assessing appropriate rehabilitation exercises without overloading on one side.

EVALUATION OF A TRI-COMPARTMENT OFFLOADER KNEE BRACE: A PROSPECTIVE STUDY IN INDIVIDUALS WITH KNEE OSTEOARTHRITIS

Purpose: Knee Osteoarthritis (KOA) is a leading cause of physical disability worldwide. Individuals who suffer from KOA experience pain, reduced mobility, and lower quality of life. Considering the upward trend in KOA diagnoses, the economic burden of knee replacement, and the surgical backlog from COVID-19, the need for alternative conservative treatments is pressing. Bracing is an economical and accessible form of conservative treatment. Traditional KOA braces only offload one knee compartment.

MOVEMENT STARTEGIES ADOPTED BY INDIVIDUALS WITH MEDIAL KNEE OA IN RESPONSE TO PRESSURE-BASED AUDITORY FEEDBACK GAIT RERAINING

Purpose: Structural progression of medial knee osteoarthritis (OA) is associated with an increased knee adduction moment (KAM), a surrogate measure of the compartmental knee loads. The KAM is thus a target for mechanical intervention. Based on real-time pressure data and individualized training thresholds, the use of plantar pressure-based auditory feedback to shift weight medially was found to reduce the KAM in individuals with medial knee OA. However, its potential mechanisms remain unclear. Thus, this study aimed to elucidate movement strategies adopted by individuals with medial knee OA in response to pressure-based feedback gait retraining and compare movement strategies of substantial and partial responders of the intervention.

High Tibial Osteotomy Versus Unicompartmental Knee Arthroplasty for Unicompartmental Knee Osteoarthritis: A Systematic Review and Meta-Analysis.

High tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) are commonly performed procedures for the treatment of compartmental knee osteoarthritis; however, the optimal procedure remains controversial. We conducted this systematic review and meta-analysis to compare the functional outcomes and assess complications and revision rates between the two techniques. We searched electronic databases for relevant studies comparing HTO versus UKA for unicompartmental knee osteoarthritis. Continuous data as visual analogue scale (VAS), range of motion, and free walking speed were pooled as mean differences (MDs). Dichotomous data as functional knee outcomes, complications, and revision were pooled as odds ratios (ORs), with 95% confidence interval (CI), using R software for windows. Twenty-five studies involving 8185 patients were included. Meta-analysis showed that HTO was associated with higher risk of complications (OR = 2.47, 95% CI [1.52, 4.04]), poorer functional results (excellent/good) (OR = 0.32, 95% CI [0.21, 0.49]), and greater range of motion (MD = 7.05, 95% CI [2.41, 11.68]) compared to UKA. No significant differences were found between the compared groups in terms of VAS (MD = 0.14, 95% CI [- 0.08, 0.36]), revision rates (OR = 1.30, 95% CI [0.65, 2.60]), and free walking speed (MD = - 0.05, 95% CI [- 0.11, 0.00]). This study showed that UKA achieved fewer complications, better functional outcomes, and less range of motion compared to HTO. No significant differences were detected between HTO and UKA in terms of VAS and revision rate. Treatment options should be personalized to each patient considering factors such as their age, activities of daily living, their body mass index, and severity of osteoarthritis. II. The online version contains supplementary material available at 10.1007/s43465-022-00620-9.

Lateral Meniscus Allograft Transplantation in a Skeletally Immature Patient

Background: Lateral meniscus deficiency in young patients typically results from irreparable lateral meniscus tears, often associated with discoid meniscus. Such cases present a challenging clinical scenario given the known natural history of meniscus deficiency leading to degenerative lateral knee compartment changes. Managing this problem in a skeletally immature patient presents additional clinical and surgical considerations. Indications: Lateral meniscus allograft transplantation (LMAT) is indicated in patients with prior total or subtotal lateral meniscectomy resulting from irreparable lateral meniscus tears, with the goal of providing chondroprotection to the lateral compartment of the knee. Patients are assessed preoperatively for ligamentous stability of the knee, mechanical alignment, and associated chondral injuries to determine whether secondary procedures may be indicated. Technique Description: We present an all-arthroscopic technique for LMAT using small bone plugs in the anterior and posterior meniscus roots secured through 2 separate anatomic root drill tunnels tied over a bone bridge. The meniscus allograft is further secured using an outside-in suture repair technique. Special attention is given to meniscus allograft preparation, anatomic meniscus root identification, and drilling using a minimally disruptive transphyseal technique. Graft passage, suture management, and meniscus fixation and repair are also highlighted. Results: Anticipated outcomes from LMAT in skeletally mature patients are excellent, particularly if preexisting chondral degenerative changes are not present. Prior studies with greater than 7-year follow-up in adolescent patients undergoing meniscus allograft transplantation have shown reoperation rates of less than 6% with no growth disturbances noted, with most patients able to return to their prior level of sport. Computed tomography modeling data using this technique shows a proximal tibial physeal surface area disruption of less than 2.5%; therefore, the risk of growth disturbance is very low. Discussion/Conclusion: The surgical technique demonstrated here offers a safe and effective approach for the management of lateral meniscus deficiency after subtotal lateral meniscectomy for irreparable meniscus tears in skeletally immature patients. The chondroprotective effect of the lateral meniscus can be restored with an anatomically placed lateral meniscus allograft with minimal disruption to the proximal tibial physis.

Overview of posterior knee arthroscopy in the medial meniscal repair: Technical note

Preservation of the meniscus in bucket handle medial meniscal tears (BHMMTs) and posterior meniscocapsular (ramp) lesions is challenging. Current efforts are being made in the scientific community to (1) introduce new ways of gaining easier and better field of view over the repair site and (2) increase the chance of meniscal healing through effective augmentation procedures. The current note introduces a way to achieve good exposure of posterior knee compartments and proposes an augmentation technique that involves exposing the local non-articulating subchondral cancellous bone and making in situ clots.

Heterogeneity of cartilage damage in Kellgren and Lawrence grade 2 and 3 knees: the MOST study

Eligibility for clinical trials in osteoarthritis (OA) is usually limited to Kellgren-Lawrence (KL) grades 2 and 3 knees. Our aim was to describe the prevalence and severity of cartilage damage in KL 2 and 3 knees by compartment and articular subregion. The Multicenter Osteoarthritis (MOST) study is a cohort study of individuals with or at risk for knee OA. All baseline MRIs with radiographic disease severity KL2 and 3 were included. Knee MRIs were read for cartilage damage in 14 subregions. We determined the frequencies of no, any and widespread full-thickness cartilage damage by knee compartment, and the prevalence of any cartilage damage in 14 articular subregions. 665 knees from 665 participants were included (mean age 63.8±7.9 years, 66.5% women). 372 knees were KL2 and 293 knees were KL3. There was no cartilage damage in 78 (21.0%) medial tibio-femoral joint (TFJ), 157 (42.2%) lateral TFJ and 62 (16.7%) patello-femoral joint (PFJ) compartments of KL2 knees, and 17 (5.8%), 115 (39.3%) and 35 (12.0%) compartments, respectively, of KL3 knees. There was widespread full-thickness damage in 94 (25.3%) medial TFJ, 36 (9.7%) lateral TFJ and 176 (47.3%) PFJ compartments of KL2 knees, and 217 (74.1%), 70 (23.9%) and 104 (35.5%) compartments, respectively, of KL3 knees. The subregions most likely to have any damage were central medial femur (80.5%), medial patella (69.8%) and central medial tibia (69.9). KL2 and KL3 knees vary greatly in cartilage morphology. Heterogeneity in the prevalence, severity and location of cartilage damage in in KL2 and 3 knees should be considered when planning disease modifying trials for knee OA.

Prognostic factors for medial open-wedge high tibial osteotomy with spacer implantation in patients with medial compartmental knee osteoarthritis

BackgroundTo identify medial open-wedge high tibial osteotomy (MOWHTO) prognostic factors with wedge-shaped spacer implantation (spacer-type MOWHTO) for varus medial compartment knee osteoarthritis.MethodsPatients who underwent spacer-type MOWHTO between August 2018 and September 2019 were prospectively enrolled in this study. Patients were divided into effective group and invalid group based on the Western Ontario and McMasters University Osteoarthritis Index (WOMAC) score one year postoperatively. The variables assessed at baseline and one year postoperatively including age, sex, body mass index (BMI), Kellgren–Lawrence (K–L) grade, hip–knee–ankle angle (HKAA), medial proximal tibial angle (MPTA), posterior tibial slope angle (PTSA), Blackburn–Peel index (BPI), duration of symptoms, and WOMAC score were compared. Prognostic factors were analyzed using logistic regression, and the corresponding odds ratios were also calculated.ResultsA total of 104 patients were enrolled in the study protocol at one year postoperatively. The WOMAC score decreased from 72.39 ± 12.95 at baseline to 20.06 ± 12.96 at one year postoperatively. Univariate analysis revealed that the significant predictors of the WOMAC score were age > 70 years, BMI > 30 kg/m2, K–L grade IV, and pre-HKAA > 10° (P < 0.1 for all). Multivariable logistic regression analysis revealed that age > 70 (OR = 4.861) and K–L grade IV (OR = 6.590) were significantly associated with the higher WOMAC score at one year postoperatively.ConclusionsSpacer-type MOWHTO is an effective treatment for osteoarthritis with varus deformity. The prognostic factors for spacer-type MOWHTO are age and K–L grade.

SIZE OF KNEE OSTEOPHYTES is under‐estimated as Assessed by MRI USING CT AS A REFERENCE STANDARD

The radiographic diagnosis of knee osteoarthritis (OA) is based on the presence of a definite osteophyte (OP). Epidemiologic studies and clinical trials commonly employ MRI using standard clinical sequences and OP assessment is one of the features included. Commonly used sequence protocols in such studies are based on triplanar fat suppressed T2- or proton density-weighted sequences with bony features as well as fibrous and lipomatous tissues appearing hypointense. This may potentially result in underestimation of such features including osteophyte assessment. Computed tomography (CT) is considered as the modality of choice for the analysis of OPs and may therefore be considered a reference standard. To explore the diagnostic performance of routine MRI as used in observational studies and clinical trials of knee OA for the assessment of OPs in all three knee compartments and the femoral notch using CT as a reference standard. The Strontium Ranelate Efficacy in Knee Osteoarthritis Trial (SEKOIA) clinical trial explored the effect of 3 years of treatment with strontium ranelate in patients with primary knee OA. All patients included in the current study participated in the CT sub-study of SEKOIA. In the current investigation, baseline data from three different centers were used. OPs were scored using a modified MOAKS scoring system in the patellofemoral (PFJ), the medial tibio-femoral (TFJ) and the lateral TFJ. Size was assessed from 0 to 3 in 18 locations. Descriptive statistics were used to describe differences in ordinal grading between CT and MRI. In addition, weighted-kappa statistics were employed to assess agreement between scoring using the two methods. Finally, sensitivity, specificity, positive predictive value and negative predictive value as well as AUC measures of diagnostic performance were employed using CT as the reference standard. Mean age of the randomized patients was 62.9 ±7.5 years with a majority of women (70%). Body mass index was 29.9±5.0 kg/m 2 . The target knee JSW was 3.50±0.84 mm at baseline, patients were Kellgren and Lawrence grade 2 (62%) or 3 (38%). Included were 74 patients with available MRI and CT data. Altogether 1332 locations were evaluated. For the PFJ MRI detected 141 (72%) of 197 CT-defined OPs with a w-kappa of 0.58 (95% CI [0.52-0.65]). In the medial TFJ, MRI detected 178 (81%) of 219 CT-OPs with a w-kappa of 0.58 (95% CI [0.51-0.64]). For the lateral compartment these numbers were 84 (70%) of 120 CT-OPs with a w-kappa of 0.58 (95% CI [0.50-0.66]). Regarding disagreement, for the PFJ MRI underestimated OP size in 94 cases (21%) and over-estimated in 27 cases (6%). For the medial TFJ these numbers were 90 (20%) and 29 (7%), and for the lateral TFJ 67 (15%) and 15 (3%). Details of the diagnostic performance analysis are presented in Table 1 . MRI underestimates presence and size of osteophytes in all 3 knee compartments. However, the sensitivity of >0.9 for OP detection in the medial compartment, which is commonly the compartment of relevance in clinical DMOAD trials, reflects that MRI is adequately able to detect osteophytes that commonly define structural disease. CT may be helpful particularly reading assessment of small osteophytes particularly in early disease. No funding was received for this sub-analysis of the SEKOIA Study AG has received consultancies, speaking fees, and/or honoraria from Pfizer, Novartis, AstraZeneca, Merck Serono, and TissueGene and is President and shareholder of Boston Imaging Core Lab (BICL), LLC a company providing image assessment services. FWR is Chief Medical Officer and shareholder of BICL, LLC. and has received consultancies, speaking fees, and/or honoraria from Calibr –California Institute of Biomedical Research and Grünenthal, GmbH CORRESPONDENCE ADDRESS: frank.roemer@uk-erlangen.de .

BONE-MUSCLE-FAT INTERACTIONS AND PERFUSIVE EVIDENCE OF INFLAMMATION IN NON-OVERWEIGHT POSTMENOPAUSAL WOMEN WITH EARLY KNEE OA

Postmenopausal women are affected by a decline of estrogen resulting in an established insult on bone (loss), muscle (loss), and fat (gain). These effects are likely not limited to central sites. We were interested in potential damage to the knee in this process and how it contributes to known phenotypes observed in osteoarthritis within this population of women. To glean evidence of inflammation, we investigated perfusion kinetics within periarticular bone, muscle, and fat tissues. To investigate how periarticular muscle and fat relate to subchondral bone properties; and to understand how perfusion may mediate these relationships. This was a cross-sectional study of 52 postmenopausal women recruited by convenience sampling at the University Health Network (Toronto). Women 60-85 years old with evidence of knee pain were included if their BMI upon screening was <=25 kg/m 2 and had no renal disease or contraindications to MRI or Gadolinium for Dynamic Contrast-Enhanced (DCE)-MRI. Time resolution on DCE-MRI scans was 7 ms and Toft's pharmacokinetic model was used to estimate perfusion rate, Kep, within each knee compartment and the infrapatellar fat pad (IPFP) using Tissue4D (Siemens) (Fig 1). Periarticular inter- and intramuscular fat (IMF) was segmented on transaxial proton-density weighted MRI using the iterative threshold-seeking algorithm (ITSA) in Python (Fig 2). Subchondral BMD, periarticular muscle mass, and IPFP content were quantified from compartment-specific pQCT scans at 200 µm in-plane pixel size on Stratec software (Fig 3). Where relevant, compartment-specific associations were obtained using general linear or logistic regression models, adjusting for age and BMI at minimum, with 95% confidence. A lower periarticular (calf side) muscle mass (b= -0.58(-1.02,-0.15)per 1mg) and density (b= -2.76(-5.35,-0.17)per 1mg/cc) was significantly associated with higher medial and lateral (b= -4.57(-7.21,-1.93)per 1mg/cc) subchondral BMD (mg/cc) of the tibia. While the directionality was similar for MR measures of IMF on the calf side, it was only marginally significant. In contrast, a higher IMF volume on the thigh side was associated with lower subchondral BMD of medial femoral (b= -2.39(-4.09,-0.69)) and tibial (b= -1.58(-3.05,-0.11)) compartments. Both higher periarticular IMF(MRI) and lower muscle mass(CT) were correlates of greater perfusion (Kep) of the lateral tibia (b= 1.69 to 2.88 per 1unit, p<0.02). Correspondingly, a higher perfusion of the lateral tibia(b=1.25(0.34,2.15)) was associated with a co-localized higher subchondral BMD. On the other hand, greater perfusion in the IPFP was related to a lower co-localized subchondral BMD (b= -1.70 to -2.22, p<0.01). Although no formal mediation analysis was performed in this smaller pre-pandemic sample, there is evidence to suggest that periarticular muscle and fat may influence subchondral bone by triggering nearby inflammation. The translated effects appear to differ - with correlates on the calf/tibia side resulting in higher BMD, and correlates on the thigh/femur side resulting in lower BMD. It is possible that the observed tibial BMD may reflect the beginning of a collapsing architecture. CIHR PJT156274. Arthritis Society Ken Smith Stars Career Development Award. None of the authors have disclosures. CORRESPONDENCE ADDRESS: andy.wong@uhnresearch.ca

Radiographic Measurements of Normal Knee Joint Space in Adults

Introduction: The knee joint is the space between the femoral and tibial condyles. The tibiofemoral articulations are separated by articular cartilages and menisci; with little contributions from cruciate ligaments. These are collectively seen on a radiograph as a radiolucent area between the bony tibial and femoral condyles. This study was conducted to measure the normal knee joint space in patients referred for X-Ray to the Department of Radiology of a tertiary care hospital.&#x0D; Methods: This descriptive cross-sectional study was performed from 1st January to 1st April 2021 in the Department of Radiology and Imaging, Tribhuvan University Teaching Hospital (TUTH). A total of 157 patients were involved. The radiographic joint space width in the knee joint was measured in both medial and lateral compartments of bilateral knees in correlation with age and gender.&#x0D; Results: The mean right medial, left medial, right lateral, and left lateral spaces for females were 0.25±0.08 cm, 0.23±0.09 cm, 0.49±0.10 cm, and 0.49±0.29 cm respectively. Similarly, the mean right medial left medial, right lateral, and left lateral spaces for males were 0.26±0.07 cm, 0.10±0.09 cm, 0.18±0.09 cm, and 0.17±0.08 cm respectively. There was a strong positive correlation between both right and left joint spaces about age.&#x0D; Conclusion: The radiographic reference values for the joint space width were obtained, showing a positive correlation with age and no significant gender variations in bilateral knees.

Knee Scores of Patients with Non-Lateral Compartmental Knee Osteoarthritis Undergoing Mobile, Fixed-Bearing Unicompartmental Knee and Total Knee Arthroplasties: A Randomized Controlled Trial.

ObjectiveTo evaluate knee scores and clinical efficacies of patients with non‐lateral unicompartmental knee osteoarthritis (OA) who randomly underwent mobile‐bearing (MB) unicompartmental knee arthroplasty (UKA), fixed‐bearing (FB) UKA, and total knee arthroplasty (TKA).MethodsFrom September 2015 to February 2017, a prospective, randomized, parallel, single‐center trial of 180 patients (78 males and 102 females; 63.3 ± 6.9 years) with non‐lateral compartmental knee OA was performed in the first author‐affiliated hospital. The patients were randomly divided into three groups (each group included 60 patients) and received medial cemented Oxford phase 3 MB UKA, medial cemented Link FB UKA, or cemented DePuy Sigma PFC TKA, respectively. A similar perioperative management and fast‐track surgery program was carried out for all patients. The knee scores at 3‐year follow‐up after operation and clinical efficacies of these three groups of patients were recorded, investigated, and compared.ResultsPrimarily, compared to the TKA group, the UKA groups (MB UKA and FB UKA) had shorter operative time (median 63.2 < 67.1 min), less bleeding (8.6 < 30.0 mL), earlier resumption of walking without crutches (3.0 < 8.0 days) and walking up and down the stairs (5.0 < 10.0 days) (P < 0.001), higher FJS scores (78.0 > 74.5) (P = 0.007), better results in all knee scores (except VAS and KSS function scores) (P < 0.05), and a larger maximum flexion angle of the knee at the 3‐year follow‐up (123.0° > 96.0°) (P = 0.001). Secondarily, compared to the TKA group, the MB UKA group showed better results in the Western Ontario and McMaster Universities index (WOMAC) stiffness (83.6 > 79.6), WOMAC total (86.3 > 83.2), Oxford knee score (OKS) (20.0 < 23.0), Forgotten Joint Score (FJS) (78.5 > 74.5), and a larger maximum flexion angle of the knee (123.0 > 96.0) (P < 0.05). Moreover, the FB UKA group showed higher Hospital for Special Surgery Knee Score (HSS) (91.0 > 88.5), WOMAC stiffness (84.3 > 79.6), WOMAC function (85.2 > 81.7), WOMAC total scores (87.6 > 83.2), and a larger maximum flexion angle of the knee (119.0° > 96.0°) than the TKA group (P < 0.05). Overall, there was no significant difference in all knee scores and maximum flexion angles of the knee for the MB UKA and FB UKA groups (P > 0.05). There was one case with original bearing dislocation in MB UKA group. One patient with displacement of the femoral component caused by a fall injury, and another patient, who lost his life in a car accident, were involved in the FB UKA group. There was an infection case and an intermuscular vein thrombosis case in TKA group.ConclusionUKA showed more advantages than TKA; however, there was no significant difference between the MB UKA and FB UKA groups for treatment of non‐lateral compartmental knee OA.

Increase in cartilage degeneration in all knee compartments after failed ACL reconstruction at 4\xa0years of follow-up

PurposeDegeneration of the cartilage after anterior cruciate ligament reconstruction (ACL-R) is known, and further deterioration can be expected in patients with tunnel malplacement or partial meniscal resection. It was hypothesized that there is a significant increase in cartilage degeneration after failed ACL-R.Material and methodsIsolated ACL revision surgery was performed in 154 patients at an interval of 46 ± 33 months (5–175 months) between primary and revision surgery. Cartilage status at the medial, lateral femorotibial, and patellofemoral compartments were assessed arthroscopically during primary and revision ACL-R in accordance with the Outerbridge classification. Tunnel placement, roof angle, and tibial slope was measured using anteroposterior and lateral radiographic views.ResultsCartilage degeneration increased significantly in the medial femorotibial compartment, followed by the lateral and patellofemoral compartments. There was a correlation between both cartilage degeneration in the patellofemoral compartment (PFC) (rs = 0.28, p = 0.0012) and medial tibial plateau (Rs = 0.24, p = 0.003) in relation to the position of tibial tunnel in the frontal plane. Worsening of the cartilage status in the medial femorotibial compartment, either femoral or tibial, was correlated with the tibial aperture site in the lateral view (Rs = 0.28, p < 0.001). Cartilage degeneration in the lateral compartment of the knee, on both femoral or tibial side, was inversely correlated with the femoral roof angle (Rs = −0.1985, p = 0.02). Meniscal tears, either at the medial or lateral site or at both, were found in 93 patients (60%) during primary ACL-R and increased to 132 patients (86%) during revision ACL-R.DiscussionAccelerated cartilage degeneration and high prevalence of meniscal lesions are seen in failed ACL-R. Tunnel placement showed significant impact on cartilage degeneration and may partially explain the increased risk of an inferior outcome when revision surgery is required after failed primary ACL-R.Level of evidence: Level IV—retrospective cohort study.

An Efficient One-Step Moment Balancing Algorithm for Computing Medial and Lateral Knee Compartment Contact Forces.

The knee adduction moment is associated with the progression of knee osteoarthritis (OA). The adduction moment reflects the net effect of muscles, passive tissues and bone-on-bone contact forces. Medial compartment OA is more common than lateral and therefore our ability to correctly partition bone-on-bones forces across the medial and lateral compartments is key to understanding mechanical factors associated with the onset and progression of knee OA. In this technical brief we present an efficient one-step moment balancing algorithm linking the sagittal and frontal planes in the determination of musculotendon forces. Novel to the one-step approach is the introduction of a penalty function limiting total compressive force from acting in the lateral compartment when the internal moment is net abduction (i.e., external knee adduction). Medial and lateral knee contact forces were computed using the one-step moment balancing algorithm for 10 subjects walking at a self-selected pace and compared to values determined using a well-established two-step frontal moment balancing approach. Overall, average peak differences in magnitude and timing were small and the ensemble-averaged contact force profiles were similar between methods. The only statistical difference was slightly larger (0.2 BWs) peak medial contact force for the one-step method during the first half of stance, however these differences are small relative to peak values and would not likely alter interpretation of the data. The 1-step moment balancing method is a more efficient methodology for computing medial and lateral knee contact forces that can be used in place of two-step frontal plane moment balancing.

Q&amp;A: Rating Patellofemoral Arthroplasty

Q&amp;A: Rating Patellofemoral Arthroplasty

Second-look arthroscopic cartilage status is related to intermediate-term outcomes after medial opening-wedge high tibial osteotomy.

To determine the relationship between articular cartilage status and clinical outcomes after medial opening-wedge high tibial osteotomy (MOHTO) for medial compartmental knee osteoarthritis at intermediate follow-up. We reviewed 155 patients (155 knees) who underwent MOHTO from January 2008 to December 2016 followed by second-look arthroscopy with a mean 5.3-year follow-up (2.0 to 11.7). Arthroscopic findings were assessed according to the International Cartilage Repair Society (ICRS) Cartilage Repair Assessment (CRA) grading system. Patients were divided into two groups based on the presence of normal or nearly normal quality cartilage in the medial femoral condyle: good (second-look arthroscopic) status (ICRS grade I or II; n = 70), and poor (second-look arthroscopic) status (ICRS grade III or IV; n = 85) groups at the time of second-look arthroscopy. Clinical outcomes were assessed using the International Knee Documentation Committee (IKDC) score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and 36-Item Short Form survey. Significant improvements in all clinical outcome categories were found between the preoperative and second-look arthroscopic assessments in both groups (p < 0.001). At the latest follow-up, the mean IKDC and WOMAC scores in the good status group further improved compared with those at the time of second-look arthroscopic surgery (p < 0.001), which was not shown in the poor status group. The mean IKDC (good status, 72.8 (SD 12.5); poor status, 64.7 (SD 12.1); p = 0.002) and mean WOMAC scores (good status, 15.7 (SD 10.8); poor status, 21.8 (SD 13.6); p = 0.004) significantly differed between both groups at the latest follow-up. Moreover, significant correlations were observed between ICRS CRA grades and IKDC scores (negative correlation; p < 0.001) and WOMAC scores (positive correlation; p < 0.001) at the latest follow-up. Good cartilage status was found more frequently in knees with the desired range of 2° to 6° valgus correction than in those with corrections outside this range (p = 0.019). Second-look arthroscopic cartilage status correlated with clinical outcomes after MOHTO at intermediate-term follow-up, despite the relatively small clinical differences between groups. Cite this article: Bone Joint J2021;103-B(11):1686-1694.

Outcomes of Combined Unicompartmental Knee Replacement and Anterior Cruciate Ligament Reconstruction: A Systematic Review

Abstract Background The incidence of osteoarthritis of the medial compartment after ACL injury has been quoted to range from 33% to 70%. Medial osteoarthritis in ACL deficient knee is a challenge. Patients are mainly young and active. First reports highlighted a higher incidence of complications, in terms of tibial loosening and higher revision rate, when UKA were performed in ACL-deficient knees. They defined ACL deficiency is a contraindication to UKA. Objectives A systematic review and meta-analysis of literature to assess functional outcomes of combined unicompartmental knee arthroplasty with ACL reconstruction and revision rate. Data Sources The following electronic databases were searched up to 2019: PubMed, Google Scholar search engine, JBJS {Journal of bone and joint Surgery}, Cochrane database of systematic reviews, EMBASE and Science Direct. Results A total of 10 studies met the inclusion criteria encompassing 218 patients who were treated with simultaneous ACL reconstruction and unicompartmental knee arthroplasty. The mean age was 49.5 years (range from 36 to 71) with a mean follow-up of 49.3 months (range from 9 to 258). There was an improvement in mean Oxford Score from 29 to 42.5. The mean knee society score improved from 88.3 to 159. Complications reported included tibial inlay dislocation (n = 3), conversion to a total knee arthroplasty (n = 2), infection requiring two-stage revision (n = 2), stiffness requiring manipulation under anaesthesia (n = 1). Average revision rate was 1.8%. Conclusion Literature has strong evidence to support that combined UKA and ACL reconstruction show good functional outcomes and less revision rate. It is a valid treatment option for MOA more in young age group in whom MOA secondary to ACL tear and intact other knee compartments. there is no clinical trial or study suggest that UKA and ACL reconstruction is superior to UKA with tibial slope change or using fixed bearing prosthesis for MOA in ACL deficient knee with instability.

Long-Term Survivorship of Closed-Wedge High Tibial Osteotomy for Severe Knee Osteoarthritis: Outcomes After 10 to 37 Years.

Background:High tibial osteotomy (HTO) was developed as a joint-preserving procedure to treat relatively young patients with isolated medial compartmental knee osteoarthritis (OA). Long-term survivorship after HTO is important to determine whether patients will need additional surgery.Purpose:To determine the long-term (>35-year) survivorship and prognostic factors for closed-wedge HTO (CWHTO) for severe medial OA.Study Design:Case series; Level of evidence, 4.Methods:We retrospectively evaluated patients who underwent CWHTO for severe medial knee OA between 1983 and 2009 at our institution, Nagoya University Graduate School of Medicine (Nagoya, Japan). Patient demographics, follow-up period, and pre- and postoperative femoral-tibial angle (FTA) were reviewed. The patients or the relatives of the patients were interviewed by telephone to record postoperative status, including conversion to total knee arthroplasty (TKA).Results:Of the 74 CWHTO procedures performed, we evaluated 56 procedures in 45 patients (mean age at time of surgery, 56.8 years). The mean follow-up period was 17.1 years. Nine knees (16.1%) underwent conversion to TKA. The mean time to TKA conversion was 15.6 years. Kaplan-Meier analysis revealed a 10-year survival rate of 90.1%, a 15-year rate of 83.8%, a 20-year rate of 75.9%, and a 35-year rate of 75.9%. Log-rank test showed that age ≥55 years (P = .044), body mass index (BMI) ≥25 kg/m2 (P = .0016), and preoperative FTA <185° (P = .0034) were risk factors associated with TKA conversion. Multivariate analyses adjusted for age and sex identified BMI ≥25 kg/m2 (hazard ratio [HR], 13.4; 95% CI, 1.7-106.9; P = .014) and preoperative FTA <185° (HR, 4.2; 95% CI, 1.1-16.6; P = .04) as risk factors associated with TKA conversion.Conclusion:The survival rate of CWHTO for severe medial knee OA was 90.1% at 10 years, 83.8% at 15 years, and 75.9% at 20 years and 35 years. Furthermore, a BMI ≥25 kg/m2 and FTA <185° were the independent risk factors associated with TKA conversion after CWHTO.

Associations Between Cadence and Knee Loading in Patients With Knee Osteoarthritis.

To test the hypothesis that higher walking cadence is associated with lower knee loading, while controlling for walking speed, in patients with medial compartment tibiofemoral osteoarthritis (OA). A total of 691 patients underwent quantitative gait analysis, including 3-dimensional knee moments and temporospatial parameters. Using multivariate linear regression, we tested the association of walking cadence with the knee adduction moment angular impulse (a surrogate measure of medial knee compartment load throughout the stance), while controlling for walking speed. We repeated the analysis while also adjusting for sex, age, body mass index, radiographic OA, knee pain, lateral trunk lean, foot progression angle, and mechanical axis angle, and while replacing the knee adduction moment angular impulse with other surrogate measures of knee loading. While controlling for walking speed, we found that a lower cadence was associated with higher knee adduction moment angular impulse (standardized β = -0.396, P < 0.001), suggesting a 0.02% body weight × height × seconds (%BW × Ht × s) decrease in impulse for each step per minute increase in cadence (unstandardized β -0.020 %BW × Ht × s [95% confidence interval -0.027, -0.015]), and remained consistent after adjusting for covariates. A lower cadence was also associated with higher first (standardized β = -0.138, P = 0.010) and second peak knee adduction moment (standardized β = -0.132, P = 0.018), higher peak knee flexion moment (standardized β = -0.128, P = 0.049), and vertical ground reaction force (standardized β = -0.116, P = 0.035) in the adjusted analyses. When controlling for walking speed, we found that a lower cadence is associated with higher knee loading per step in patients with medial tibiofemoral OA. Future research should investigate the potential beneficial biomechanical and clinical effects of increasing walking cadence in patients with knee OA.

Difference in the joint space of the medial knee compartment between full extension and Rosenberg weight-bearing radiographs

ObjectivesRadiographs are the most widespread imaging tool for diagnosing osteoarthritis (OA) of the knee. Our purpose was to determine which of the two factors, medial meniscus extrusion (MME) or cartilage thickness, had a greater effect on the difference in the minimum joint space width (mJSW) at the medial compartment between the extension anteroposterior view (extension view) and the 45° flexion posteroanterior view (Rosenberg view).MethodsThe subjects were 546 participants (more than 50 females and 50 males in their 30 s, 40 s, 50 s, 60 s, and 70 s) in the Kanagawa Knee Study. The mJSW at the medial compartment was measured from both the extension and the Rosenberg views, and the “mJSW difference” was defined as the mJSW in the Rosenberg view subtracted from the mJSW in the extension view. The cartilage region was automatically extracted from MRI data and constructed in three dimensions. The medial region of the femorotibial joint cartilage was divided into 18 subregions, and the cartilage thickness in each subregion was determined. The MME was also measured from MRI data.ResultsThe mJSW difference and cartilage thickness were significantly correlated at 4 subregions, with 0.248 as the highest absolute value of the correlation coefficient. The mJSW difference and MME were also significantly correlated, with a significantly higher correlation coefficient (0.547) than for the mJSW difference and cartilage thickness.ConclusionsThe MME had a greater effect than cartilage thickness on the difference between the mJSW at the medial compartment in the extension view and in the Rosenberg view.Key Points• The difference in the width at the medial compartment of the knee between the extension and the flexion radiographic views was more affected by medial meniscus extrusion than by cartilage thickness.