Tibiofemoral Compartment Research Articles

Knee Kinetics and Kinematics in Patients With Ankle Arthroplasty and Ankle Arthrodesis.

Background: Previous literature suggests that patients treated with total ankle arthroplasty (TAA) versus ankle arthrodesis (AA) may have better function and lower risk for adjacent joint arthritis in the foot. Little is known on how these interventions affect proximal joints such as the knee. Questions: We sought to assess whether patients with TAA and AA exhibited altered biomechanics linked to the onset and progression of knee osteoarthritis (KOA). We used the knee adduction moment (KAM), a surrogate measure for the mechanical load experienced at the medial tibiofemoral compartment, because it is linked with the onset and progression of KOA. Methods: At a minimum of 2 years postoperatively, instrumented 3-dimensional walking gait was recorded in 10 TAA and 10 AA patients at self-selected walking speeds. TAA patients had either a Salto Talaris or INBONE prosthesis. Average first and second peak KAMs (Nm/kg), KAM impulse (Nm-s/kg), and range-of-motion (ROM, °) were calculated on both the affected and unaffected limbs for each patient. Results: There were no significant differences in the KAM's first and second peaks, impulse, or knee ROM in any plane between the unaffected and affected limbs, or between TAA and AA. Conclusion: TAA and AA may not meaningfully affect ipsilateral knee kinetics and KAMs in short-term follow-up. This study highlights the importance of continuing to study these parameters in larger cohorts of patients with longer follow-up to determine how our treatment of end-stage ankle arthritis may affect the incidence or progression of ipsilateral KOA.

Identifying trajectories of T2 relaxation time over age in the medial tibiofemoral cartilage in participants with pre-radiographic knee osteoarthritis

Identifying trajectories of T2 relaxation time over age in the medial tibiofemoral cartilage in participants with pre-radiographic knee osteoarthritis

Valgus knee bracing for medial knee osteoarthritis and varus malalignment: a pilot study

Purpose: Knee bracing is inconsistently recommended in clinical guidelines for the management of knee osteoarthritis (OA). Knee OA progression may be related to altered mechanical knee loads, particularly in those with varus malignment. Valgus knee bracing is thought to alleviate symptoms by reducing loads borne through the medial tibiofemoral compartment during walking. However, the effect of valgus knee bracing on medial tibiofemoral compartment mechanical loads is not well understood. Investigations on valgus knee bracing to date have largely used the external knee adduction moment as a surrogate to infer medial tibiofemoral compartment mechanical loads.

Association between Patellofemoral and medial Tibiofemoral compartment osteoarthritis progression: exploring the effect of body weight using longitudinal data from osteoarthritis initiative (OAI).

To investigate the associations of medial and lateral patellofemoral osteoarthritis (PF-OA) at baseline with symptomatic and radiographic OA outcomes in the medial tibiofemoral compartment (MTFC) over 4years, according to baseline overweight status. Data and MRI images of 600 subjects in the FNIH-OA biomarkers consortium were used. Symptomatic worsening and radiographic progression of MTFC-OA were defined using Western Ontario and McMaster Universities Arthritis Index (WOMAC) pain scores and MTFC joint space narrowing (JSN) from baseline to 4-year follow-up. Baseline MRIs were read to establish PF-OA diagnosis. The association between baseline regional PF-OA pattern and odds for MTFC-OA progression was evaluated using regression models (adjusted for relevant confounding covariates including body mass index (BMI), age, sex, PF alignment measurements, KL grade, and knee alignment). To evaluate the effect modifying role for overweight status, stratification analysis was performed (BMI ≥ 25 vs. < 25kg/m2). At baseline, 340 (56.7%), 255 (42.5%), and 199 (33.2%) subjects had OA in the medial, lateral, and both PF compartments. Baseline medial PF-OA was associated with WOMAC pain score and MTFC JSN progression at 4years (Adjusted OR:1.56[95%CI:1.09-2.23] and 1.59[1.11-2.28], respectively) but not lateral PF-OA. In stratification analysis, overweight status was found to be an effect modifier for medial PF-OA and WOMAC pain (OR in overweight vs. non-overweight subjects:1.65[1.13-2.42] vs. 0.50[0.12-1.82]) as well as MTFC-JSN progression (1.63[1.12-2.4] vs. 0.75[0.19-2.81]). In addition to the known confounding effect of BMI for PF-OA and MTFC-OA, the overweight status may also play an effect modifier role in the association between baseline medial PF-OA and MTFC-OA progression, which is amenable to secondary prevention.

Ramp lesions are six times more likely to be observed in the presence of a posterior medial tibial bone bruise in ACL-injured patients.

The aim of this study was to determine whether posterior tibial slope (PTS), meniscal slope (MS), and bone bruise pattern (BBP), as observed on magnetic resonance imaging (MRI), differed between patients with or without medial meniscus ramp lesions at the time of anterior cruciate ligament reconstruction (ACLR). The hypothesis was that patients with a ramp lesion had a higher PTS and MS, with a different BBP than patients without a ramp lesion. Fifty-six patients undergoing ACLR were selected from an in-house registry and separated into 2 groups: (1) the RAMP group included patients with a primary ACLR and a medial meniscus ramp lesion diagnosed intraoperatively; (2) the CONTROL group included patients with a primary ACLR without ramp lesion after arthroscopic exploration of the posteromedial knee area. The two groups were matched for age, sex and type of concomitant meniscal lesions. The medial/lateral-PTS/MS and BBP were subjected to blinded evaluation on the preoperative MRI of the reconstructed knee. Twenty eight patients (21 males; 7 females) were included in each group. No significant difference could be observed between groups in terms of demographical characteristics, PTS, and MS. A posteromedial tibial plateau (PMTP) bone bruise was more often observed in the RAMP group (n = 23/28) compared to the CONTROL group (n = 12/28) (p < 0.01). The RAMP group was 6.1 (95%CI [1.8; 20.8]) times more likely to present a PMTP bone bruise. The likelihood of having a bone bruise in both the medial and lateral compartments was 4.5 (95%CI [1.2; 16.5]) times higher in the RAMP group. However, a BBP only involving the lateral tibiofemoral compartment was more likely to be observed in the CONTROL group (n = 10/28) compared to the RAMP group (n = 3/28, p < 0.05 - odds ratio 4.6 (95%CI [1.1; 19.2]). Ramp lesions were 6.1 and 4.5 times more likely to be observed in the presence of a posteromedial tibia plateau bone bruise or a combined bone bruise respectively in both the medial and lateral tibiofemoral compartment in patients undergoing ACLR. The tibial and meniscal slopes did not differ between patients with or without ramp lesions undergoing ACLR. Level III.

Lateral tenodesis procedures increase lateral compartment pressures more than anterolateral ligament reconstruction, when performed in combination with ACL reconstruction: a pilot biomechanical study

ObjectivesGiven the common occurrence of residual laxity and re-injury post anterior cruciate ligament reconstruction (ACLR), additional anterolateral procedures are increasingly used in combination with an ACLR. Despite the perception that there is a risk of over-constraining the lateral tibiofemoral (LTF) compartment, potentially leading to osteoarthritis, assessment on their effect on intra-articular compartment pressures is still lacking. Our objective was therefore, through a pilot biomechanical study, to compare LTF contact pressures after the most commonly used anterolateral procedures.MethodsA controlled laboratory pilot study was performed using 4 fresh-frozen cadaveric whole lower limbs. Through 0° to 90° of flexion, LTF contact pressures were measured with a Tekscan sensor, located under the lateral meniscus. Knee kinematics were obtained in 3 conditions of rotation (NR: neutral, ER: external and IR: internal rotation) to record the position of the knees for each loading condition. A Motion Analysis system with a coordinate system based on CT scans 3D bone modelling was used. After an ACLR, defined as the reference baseline, 5 anterolateral procedures were compared: anterolateral ligament reconstruction (ALLR), modified Ellison, deep Lemaire, superficial Lemaire and modified MacIntosh procedures. The last 3 procedures were randomised. For each procedure, the graft was fixed in NR at 30° of flexion and with a tension of 20 N.ResultsCompared with isolated ACLR, addition of either ALLR or modified Ellison procedure did not increased the overall LTF contact pressure (all p>0.05) through the full range of flexion for the IR condition. Conversely, deep Lemaire, superficial Lemaire and modified MacIntosh procedure (all p<0.05) did increase the overall LTF contact pressure compared with ACLR in IR. No significant difference was observed in ER and NR conditions.ConclusionThis pilot study, comparing the main anterolateral procedures, revealed that addition of either ALLR or modified Ellison procedure did not change the overall contact pressure in the LTF compartment through 0° to 90° of knee flexion. In contrast, the deep and superficial Lemaire, and modified MacIntosh procedures significantly increased overall LTF contact pressures when the knee was internally rotated.

Differences in impact on adjacent compartments in medial unicompartmental knee arthroplasty versus high tibial osteotomy with identical valgus alignment

BackgroundIt is unclear why medial unicompartmental knee arthroplasty (UKA) with postoperative valgus alignment causes adjacent compartment osteoarthritis more often than high tibial osteotomy (HTO) for moderate medial osteoarthritis of the knee with varus deformity. This study used a computer simulation to evaluate differences in knee conditions between UKA and HTO with identical valgus alignment. MethodsDynamic musculoskeletal computer analyses of gait were performed. The hip–knee–ankle angle in fixed-bearing UKA was changed from neutral to 7° valgus by changing the tibial insert thickness. The hip–knee–ankle angle in open-wedge HTO was also changed from neutral to 7° valgus by opening the osteotomy gap. ResultsThe lateral tibiofemoral contact forces in HTO were larger than those in UKA until moderate valgus alignments. However, the impact of valgus alignment on increasing lateral forces was more pronounced in UKA, which ultimately demonstrated a larger lateral force than HTO. Valgus alignment in UKA caused progressive ligamentous tightness, including that of the anterior cruciate ligament, resulting in compression of the lateral tibiofemoral compartment. Simultaneously, patellofemoral shear forces were slightly increased and excessive external femoral rotation against the tibia occurred due to the flat medial tibial insert surface and decreased lateral compartment congruency. By contrast, only lateral femoral slide against the tibia occurred in excessively valgus-aligned HTO. ConclusionsIn contrast to extra-articular correction in HTO, which results from opening the osteotomy gap, intra-articular valgus correction in UKA with thicker tibial inserts caused progressive ligamentous tightness and kinematic abnormalities, resulting in early osteoarthritis progression into adjacent compartments.

The aspiration test: an arthroscopic sign of lateral meniscus posterior horn instability

The suspensory mechanism of the posterior horn of the lateral meniscus (PHLM) is an anatomically complex structure including the popliteomeniscal fascicles, the meniscotibial posterior root attachment and the meniscofemoral ligaments. Damage to one or several of these structures – either through knee trauma or congenital abnormalities—can result in an instability of the PHLM that may lead to lateral knee pain, locking sensations or lack of rotational control of the knee (e.g. after anterior cruciate ligament injuries). The diagnosis of PHLM instability is complex due to the lack of reliable clinical tests and imaging signs. Direct visual dynamic inspection via arthroscopy thus remains the gold standard. However, arthroscopic probing of the PHLM is not always reliable and the precise quantification of the amount of subluxation of the PHLM can be difficult. Therefore, the main objective of this report was to describe a quick and easy arthroscopic screening test called “the aspiration test” in order to help surgeons to detect PHLM instability. During the exploration of the lateral tibiofemoral compartment with the knee kept in the figure of 4 position, the arthroscope is placed in the antero-lateral portal and directed towards the lateral tibiofemoral compartment. The aspiration test is then performed by activating the aspiration of the 4-mm shaver when located in the intercondylar notch. In case of a PHLM instability, an excessive displacement of the PHLM is observed. After repair, a second aspiration test allows to verify that the PHLM has been stabilized.

Meta-analysis on the association between knee extensor strength and structural changes of knee osteoarthritis.

This study aimed to perform a meta-analysis to evaluate whether knee extensor (KE) strength weakness was associated with increased structural worsening in knee osteoarthritis (KOA) including joint space narrowing (JSN) and cartilage loss. PubMed, Embase, Scopus, ScienceDirect, Web of Science, and Cochrane library were searched from their inception to May 2020, to identify eligible studies. Odds ratios (ORs) accompanied by 95% confidence intervals (CIs) were calculated for the relationship between KE strength and outcomes. Totally eleven longitudinal studies were included. The pooled crude OR indicated no significant association between KE strength weakness and KOA progression of JSN (OR: 1.13, 95% CI: 0.90, 1.42), and this result duplicated after confounders were adjusted (OR: 1.10, 95% CI: 0.87, 1.39). Subgroup analysis showed the association remained non-significant in sex-specific outcomes and subsets of neutral and malaligned knees, but there was a trend toward increased risk of JSN progression in female knees with low strength (OR: 1.24, 95% CI: 0.87, 1.76, I2 = 82%). The pooled crude OR showed that KE strength weakness was associated with increased risk of cartilage loss (OR:1.43, 95% CI: 1.05, 1.95). After adjustment, we found a non-significant trend that low KE strength could increase the risk of cartilage loss (OR: 1.25, 95% CI: 0.95, 1.64), and this trend was separately observed in tibiofemoral or patellofemoral compartments. This meta-analysis suggested that KE strength weakness was not significantly associated with an increased risk of radiographic structural KOA progression in patients with KOA or known risk factors for KOA. However, there was a trend that women with weaker KE strength displayed a higher risk of JSN worsening and that KE strength weakness had an association with an increased risk of cartilage damage. Key points • Knee extensor strength weakness is not significantly associated with an increased risk of radiographic structural KOA progression in patients with or at risk of knee osteoarthritis. • There is a non-significant trend toward an increased risk of JSN progression in female knees with low knee extensor strength. • There is a trend that low KE strength can increase the risk of cartilage loss no matter in tibiofemoral or patellofemoral compartments, but it's not significant.

The effect of lateral extra-articular tenodesis on in vivo cartilage contact in combined anterior cruciate ligament reconstruction.

Lateral extra-articular tenodesis (LET) may confer improved rotational stability after anterior cruciate ligament reconstruction (ACLR). Little is known about how LET affects in vivo cartilage contact after ACLR. The aim of this study was to investigate the effect of LET in combination with ACLR (ACLR + LET) on in vivo cartilage contact kinematics compared to isolated ACLR (ACLR) during downhill running. It was hypothesised that cartilage contact area in the lateral compartment would be larger in ACLR + LET compared with ACLR, and that the anterior-posterior (A-P) position of the contact center on the lateral tibia would be more anterior after ACLR + LET than after ACLR. Twenty patients were randomly assigned into ACLR + LET or ACLR during surgery (ClinicalTrials.gov:NCT02913404). At 6months and 12months after surgery, participants were imaged during downhill running using biplane radiography. Tibiofemoral motion was tracked using a validated registration process. Patient-specific cartilage models, obtained from 3T MRI, were registered to track bone models and used to calculate the dynamic cartilage contact area and center of cartilage contact in both the medial and lateral tibiofemoral compartments, respectively. The side-to-side differences (SSD) were compared between groups using a Mann-Whitney U test. At 6months after surgery, the SSD in A-P cartilage contact center in ACLR + LET (3.9 ± 2.6mm, 4.4 ± 3.1mm) was larger than in ACLR (1.2 ± 1.6mm, 1.5 ± 2.0mm) at 10% and 20% of the gait cycle, respectively (p < 0.01, p < 0.05). There was no difference in the SSD in cartilage contact center at 12months after surgery. There was no difference in SSD of cartilage contact area in the medial and lateral compartments at both 6 and 12months after surgery. There were no adverse events during the trial. LET in combination with ACLR may affect the cartilage contact center during downhill running in the early post-operation phase, but this effect is lost in the longer term. This suggests that healing and neuromuscular adaptation occur over time and may also indicate a dampening of the effect of LET over time. (337 /350 words) LEVEL OF EVIDENCE: Level II.

Biomechanical Study of a Tricompartmental Unloader Brace for Patellofemoral or Multicompartment Knee Osteoarthritis

Objective: Off-loader knee braces have traditionally focused on redistributing loads away from either the medial or lateral tibiofemoral (TF) compartments. In this article, we study the potential of a novel “tricompartment unloader” (TCU) knee brace intended to simultaneously unload both the patellofemoral (PF) and TF joints during knee flexion. Three different models of the TCU brace are evaluated for their potential to unload the knee joint.Methods: A sagittal plane model of the knee was used to compute PF and TF contact forces, patellar and quadriceps tendon forces, and forces in the anterior and posterior cruciate ligaments during a deep knee bend (DKB) test using motion analysis data from eight participants. Forces were computed for the observed (no brace) and simulated braced conditions. A sensitivity and validity analysis was conducted to determine the valid output range for the model, and Statistical Parameter Mapping was used to quantify the effectual region of the different TCU brace models.Results: PF and TF joint force calculations were valid between ~0 and 100 degrees of flexion. All three simulated brace models significantly (p < 0.001) reduced predicted knee joint loads (by 30–50%) across all structures, at knee flexion angles >~30 degrees during DKB.Conclusions: The TCU brace is predicted to reduce PF and TF knee joint contact loads during weight-bearing activity requiring knee flexion angles between 30 and 100 degrees; this effect may be clinically beneficial for pain reduction or rehabilitation from common knee injuries or joint disorders. Future work is needed to assess the range of possible clinical and prophylactic benefits of the TCU brace.

Surgical meniscal lesions in stable knee: Topographic description in a prospective series of 1424 cases

BackgroundThe epidemiology of meniscal lesions in stable knee has been a focus of study, but exact topography is not clearly known. Tear patterns are thought to differ between pathologies and the difference between a traumatic and a degenerative pattern is not always easy to draw. In 2010, ISAKOS designed a questionnaire to standardize assessment. The main objective of present study was to detail the precise topography and type of surgical meniscal patterns (i.e., that were operated on) in stable knee. Secondary objectives were to assess the relationship of tear pattern and cartilage lesions in the tibiofemoral compartment, and to analyze age at onset. HypothesesThe study hypotheses were that tear pattern correlates with cartilage lesions, and that mean age differs according to tear pattern, with younger onset of vertical tears, in surgery@ patients. Patients & methodsData collection for this descriptive epidemiological study was prospective, on systematic ISAKOS questionnaire. 1424 isolated meniscal tears in stable knee, operated on between 2010 and 2017, were included: 253 lateral meniscus (LM), and 1171 medial meniscus (MM). Mean age at surgery was respectively 36 and 47 years. ResultsThe most frequent tear pattern was vertical (39% in LM, 38% in MM). The more frequent locations were posterior+midpart and midpart (22% each) in LM, and posterior in MM (56%). Tears were mainly peripheral (zone 1) in LM (46%), and zone 2 in MM (46%). Mean age in medial vertical tears was 43±14 years, significantly lower (p<0.001) than in other types. Meniscal tear pattern correlated significantly with medial tibiofemoral cartilage lesion (p<0.001). DiscussionThe present study described the precise topography of isolated meniscal tears in stable knee in a large sample, using the ISAKOS questionnaire. The study hypotheses were confirmed for the medial but not the lateral meniscus. Level of evidenceIII; well-conducted non-randomized prospective comparative study.

Focal cartilage defects of the lateral compartment do influence the outcome after high tibial valgus osteotomy.

Introduction: High tibial medial open-wedge valgus osteotomy (HTO) is a well-established procedure for unicompartimental medial osteoarthritis of the young and active patient. However, the influence of cartilage defects of the lateral compartment on the total outcome remains obscure. Methods: From 2005 to 2012, a total of 63 patients underwent HTO for medial osteoarthritis of the knee at a single university orthopaedic center. Baseline data as well as intraoperative findings, including the grade and location of cartilage lesions, were evaluated retrospectively. Two groups were formed regarding the integrity of the lateral tibiofemoral compartment as measured by the Outerbridge score (group A: no lateral cartilage defects, group B: mild to moderate lateral cartilage defects). Functional outcome was assessed using the Knee and Osteoarthritis Outcome Score (KOOS), including its five subscores. Results: Comparing pre- and postoperative data, we identified an overall benefit of the HTO procedure as measured by the KOOS. Group A (no lateral cartilage defects) showed an increase in all five KOOS subscores (p = 0.00–0.01), whereas for group B (mild to moderate lateral cartilage defects), only two KOOS subscores revealed a significant increase (p = 0.03–0.04). There was also a statistically significant difference in the total KOOS score with higher values for group A at the postoperative visit. Cartilage defects with a higher Outerbridge score were associated with lower postoperative KOOS subscores. Discussion: Mild to moderate cartilage defects of the lateral compartment humble the total outcome after HTO procedure. Thus, indication for HTO should be made very carefully if any degree of lateral cartilage degeneration is present.

Medial Meniscal Allograft Transplantation

Background: This technique video reviews medial meniscal allograft transplantation (MAT) using a representative case example. Indications: Medial meniscal allograft transplantation is indicated in symptomatic patients with a deficient medial tibiofemoral compartment that has not progressed to arthritic changes. Concomitant procedures to address focal cartilage defects, ligamentous laxity, and/or limb malalignment should be performed prior to MAT or in the same surgical setting. Technique Description: Preoperative workup includes magnetic resonance imaging (MRI), prior arthroscopic pictures, and sizing radiographs. The Pollard radiographic method measures for the appropriate cryopreserved allograft size. Arthroscopic instruments remove residual meniscal tissue to a 1 mm base around the capsule. Percutaneous lengthening of the medial collateral ligament (MCL) at its femoral attachment aids visualization/instrumentation. This technique employs 8-mm bone plugs for anterior and posterior meniscal root fixation. Tunnels size 8.5 mm diameter and 10 mm depth are created. Once the meniscal allograft is placed in the joint, inside-out sutures are placed throughout the meniscal body. Sutures from the meniscal roots are secured with an anchor in the anterior proximal tibia. Results: There are numerous outcomes studies of meniscal allograft transplantation with a reported overall graft survivorship of roughly 70% at 10 years and 60% at 15 years follow-up. Discussion/Conclusion: Meniscal allograft transplantation is a temporizing measure that provides good midterm clinical results, although long-term failure rates increase incrementally. Most studies suggest return to sport is possible although activity modification is recommended.

Long-term Effect of a Single Subcritical Knee Injury: Increasing the Risk of Anterior Cruciate Ligament Rupture and Osteoarthritis

Background: Rupture of the anterior cruciate ligament (ACL) is a well-known risk factor for the development of posttraumatic osteoarthritis (PTOA), but patients with the “same injury” can have vastly different trajectories for the onset and progression of disease. Minor subcritical injuries preceding the critical injury event may drive this disparity through preexisting tissue pathologies and sensory changes. Purpose: To investigate the role of subcritical injury on ACL rupture risk and PTOA through the evaluation of pain behaviors, joint mechanics, and tissue structural change in a mouse model of knee injury. Study Design: Controlled laboratory study. Methods: Ten-week-old male C57BL/6J mice were allocated to naïve control and subcritical knee injury groups. Injury was induced by a single mechanical compression to the right hindlimb, and mice were evaluated using joint histopathology, anteroposterior joint biomechanics, pain behaviors (mechanical allodynia and hindlimb weightbearing), and isolated ACL tensile testing to failure at 1, 2, 4, or 8 weeks after injury. Results: Subcritical knee injury produced focal osteochondral lesions in the patellofemoral and lateral tibiofemoral compartments with no resolution for the duration of the study (8 weeks). These lesions were characterized by focal loss of proteoglycan staining, cartilage structural change, chondrocyte pathology, microcracks, and osteocyte cell loss. Injury also resulted in the rapid onset of allodynia (at 1 week), which persisted over time and reduced ACL failure load (P = .006; mean ± SD, 7.91 ± 2.01 N vs 9.37 ± 1.01 N in naïve controls at 8 weeks after injury), accompanied by evidence of ACL remodeling at the femoral enthesis. Conclusion: The present study in mice establishes a direct effect of a single subcritical knee injury on the development of specific joint tissue pathologies (osteochondral lesions and progressive weakening of the ACL) and allodynic sensitization. These findings demonstrate a predisposition for secondary critical injuries (eg, ACL rupture) and an increased risk of PTOA onset and progression (structurally and symptomatically). Clinical Relevance: Subcritical knee injuries are a common occurrence and, based on this study, can cause persistent sensory and structural change. These findings have important implications for the understanding of risk factors of ACL injury and subsequent PTOA, particularly with regard to prevention and management strategies following an often underreported event.

RÉSULTATS À MOYEN TERME DES PROTHÈSES UNICOMPARTIMENTALES DU GENOU À MADAGASCAR MEDIUM-TERM RESULTS OF UNICOMPARTMENTAL KNEE ARTHROPLASTY IN MADAGASCAR

Introduction: the unicompartmental knee arthroplasty (UKA) is a globally recognized procedure for the treatment of osteoarthritis of a tibiofemoral compartment. It was carried out in Madagascar since 2012 at the Joseph Ravoahangy Andrianavalona University Hospital Center (CHU-JRA) and this study is the first study concerning the UKA carried out in the country. The objective of this study is to assess the medium-term results of PUCs in Madagascar. &#x0D; Methods: this was a six-year prospective study from 2012 to 2017 carried out in the Department of Orthopedic Surgery and Traumatology of the CHU-JRA Antananarivo including all patients who received a UKA. &#x0D; Results: twelve UKA were placed in eight patients. The mean age of the patients was 73.5 years. Mechanical pain in the internal compartment of the knee was the complaint of all patients, and the diagnosis of internal tibial osteoarthritis was confirmed after the x-ray. An improvement in the IKS (International Knee Society) score was found, with the average overall score which had gone from 132.5 preoperatively to 190 at the last follow-up, an IKS knee average score increased from 65 to 95 and an IKS score function increased from 67.5 to 95. After a mean follow-up of four years, the quality of life of the patients was excellent with the KOOS (Knee Injury and Osteoarthritis Outcome Score) which went from 26/100 before the operation to 98/100. Apart from a loosened prosthesis no other complication were found. &#x0D; Conclusion: UKA is an ideal treatment for isolated osteoarthritis of a tibiofemoral compartment. It offers better physiological function, a less invasive surgical approach, a faster recovery time. This first study in Madagascar concerning the PUC found excellent mediumterm results but long-term patient follow-up will be necessary.

Obesity Is Preferentially Associated With Patellofemoral Compartment Wear: A Magnetic Resonance Imaging Assessment.

A well-known association exists between obesity and knee osteoarthritis (OA) for both incidence and progression of the disease. However, the cartilage wear patterns in OA associated with obesity are less well studied. The OA initiative, a prospective sample of 4,796 patients, was used for this study. After the application of inclusion and exclusion criteria, patients were stratified into increasing body mass index (BMI) cohorts (BMI < 25, 25 ≤ BMI < 30, 30 ≤ BMI < 40, and 40 ≤ BMI). Knee MRIs were assessed using the semiquantitative MRI Osteoarthritis Knee Score scores. Patellofemoral (PF), medial, and lateral compartment cartilage scores were compared among BMI cohorts, controlling for confounders using linear regression models. In total, 2,006 patients were present in our cohort, 773 men (38.5%) and 1,233 women (61.5%); the mean age was 61.7 ± 8.9 years. Increasing BMI was independently associated with increasing grades of PF wear for both right and left knees in the lateral patella facet (right knee β: 0.208, 95% confidence interval [CI]: 0.128 to 0.288, P < 0.001, left knee β: 0.147, 95% CI: 0.056 to 0.237, P = 0.002), medial femoral trochlea (right knee β: 0.135, 95% CI: 0.065 to 0.204, P < 0.001, left knee β: 0.142, 95% CI: 0.063 to 0.221, P < 0.001), and lateral femoral trochlea (right knee β: 0.163, 95% CI: 0.093 to 0.232, P < 0.001, left knee β: 0.147, 95% CI: 0.067 to 0.226, P < 0.001). For the right knee, increasing BMI was associated with medial compartment wear in the posterior femoral area (β: 0.070, 95% CI: 0.015 to 0.126, P = 0.013) and lateral compartment wear in the central tibial area (β: 0.070, 95% CI: 0.002 to 0.138, P = 0.045). For the left knee, increasing BMI was associated with medial compartment wear in the central femoral area (β: 0.093, 95% CI: 0.016 to 0.171, P = 0.018). Obesity is preferentially associated with increasing cartilage wear in the PF compartment in comparison to the tibiofemoral compartment. Physical therapy and exercise programs that promote weight loss should be modified to decrease forces on the PF joint.

Reliability of tibiofemoral contact area and centroid location in upright, open MRI

BackgroundImaging cannot be performed during natural weightbearing in biomechanical studies using conventional closed-bore MRI, which has necessitated simulating weightbearing load on the joint. Upright, open MRI (UO-MRI) allows for joint imaging during natural weightbearing and may have the potential to better characterize the biomechanical effect of tibiofemoral pathology involving soft tissues. However open MRI scanners have lower field strengths than closed-bore scanners, which limits the image quality that can be obtained. Thus, there is a need to establish the reliability of measurements in upright weightbearing postures obtained using UO-MRI.MethodsKnees of five participants with prior anterior cruciate ligament (ACL) rupture were scanned standing in a 0.5 T upright open MRI scanner using a 3D DESS sequence. Manual segmentation of cartilage regions in contact was performed and centroids of these contact areas were automatically determined for the medial and lateral tibiofemoral compartments. Inter-rater, test-retest, and intra-rater reliability were determined and quantified using intra-class correlation (ICC3,1), standard error of measurement (SEM), and smallest detectable change with 95% confidence (SDC95). Accuracy was assessed by using a high-resolution 7 T MRI as a reference.ResultsContact area and centroid location reliability (inter-rater, test-retest, and intra-rater) for sagittal scans in the medial compartment had ICC3,1 values from 0.95–0.99 and 0.98–0.99 respectively. In the lateral compartment, contact area and centroid location reliability ICC3,1 values ranged from 0.83–0.91 and 0.95–1.00 respectively. The smallest detectable change in contact area was 1.28% in the medial compartment and 0.95% in the lateral compartment. Contact area and centroid location reliability for coronal scans in the medial compartment had ICC3,1 values from 0.90–0.98 and 0.98–1.00 respectively, and in the lateral compartment ICC3,1 ranged from 0.76–0.94 and 0.93–1.00 respectively. The smallest detectable change in contact area was 0.65% in the medial compartment and 1.41% in the lateral compartment. Contact area was accurate to within a mean absolute error of 11.0 mm2.ConclusionsKnee contact area and contact centroid location can be assessed in upright weightbearing MRI with good to excellent reliability. The lower field strength used in upright, weightbearing MRI does not compromise the reliability of tibiofemoral contact area and centroid location measures.

Medial meniscal extrusion greater than 4 mm reduces medial tibiofemoral compartment contact area: a biomechanical analysis of tibiofemoral contact area and pressures with varying amounts of meniscal extrusion.

The primary objective of this study is to evaluate the contact areas, contact pressures, and peak pressures in the medial compartment of the knee in six sequential testing conditions. The secondary objective is to establish how much the medial meniscus is able to extrude, secondary to soft tissue injury while keeping its roots intact. Ten cadaveric knees were dissected and tested in six conditions: (1) intact meniscus, (2) 2mm extrusion, (3) 3mm extrusion, (4) 4mm extrusion, (5) maximum extrusion, (6) capsular based meniscal repair. Knees were loaded with a 1000-N axial compressive force at 0°, 30°, 60°, and 90° for each condition. Medial compartment contact area, average contact pressure, and peak contact pressure data were recorded. When compared to the intact state, there was no statistically significant difference in medial compartment contact area at 2mm of extrusion or 3mm of extrusion (n.s.). There was a statistically significant decrease in contact area compared to the intact state at 4mm (p = 0.015) and maximum extrusion (p < 0.001). The repair state was able to improve medial compartment contact area, and there was no statistically significant difference between the repair and the intact states (n.s.). No significant differences were found in the average contact pressure between the repair, intact, or maximum extrusion conditions at any flexion angle (n.s.). No significant differences were found in the peak contact pressure between the repair, intact, or maximum extrusion conditions at any flexion angle (n.s.). In this in vitro model, medial meniscus extrusion greater than 4mm reduced medial compartment contact area, but meniscal extrusion did not significantly increase pressure in the medial compartment. Additionally, meniscal centralization was effective in restoring the medial tibiofemoral contact area to intact state when the meniscal extrusion was secondary to meniscotibial ligament injury. The diagnosis of meniscal extrusion may not necessarily involve meniscal root injury. Since it is known that meniscal extrusion greater than 3 or 4mm has a biomechanical impact on tibiofemoral compartment contact area and pressures, specific treatments can be established. Centralization restored medial compartment contact area to the intact state.

Is step rate associated with worsening of patellofemoral and tibiofemoral joint osteoarthritis in women and men? The Multicenter Osteoarthritis Study.

© 2019, American College of Rheumatology This is the peer reviewed version of the following article: Step Rate and Worsening of Patellofemoral and Tibiofemoral Joint Osteoarthritis in Women and Men: The Multicenter Osteoarthritis Study, which has been published in final form at https://onlinelibrary.wiley.com/doi/full/10.1002/acr.23864. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.Objective: To determine the association of self-selected walking step rate with worsening of cartilage damage in the patellofemoral (PF) joint and tibiofemoral (TF) joint compartments at a 2-year follow-up visit. Methods: The Multicenter Osteoarthritis Study (MOST) is a prospective cohort of men and women with or at risk of knee osteoarthritis. Self-selected step rate was measured using an instrumented GAITRite walkway (CIR Systems) at the 60-month visit. Cartilage damage was semiquantitatively graded on magnetic resonance images at the 60- and 84-month visits in the medial and lateral PF and TF compartments. Step rate was divided into quartiles, and logistic regression was used to determine the association of step rate with the risk of worsening cartilage damage in men and women separately. Analyses were adjusted for age, body mass index, and knee injury/surgery. Results: A total of 1,089 participants were included. Mean ± SD age was 66.9 ± 7.5 years, mean ± SD body mass index was 29.6 ± 4.7 kg/m2, and 62.3% of the participants were women. Women with the lowest step rate had increased risk of lateral PF (risk ratio [RR] 2.1 [95% confidence interval (95% CI) 1.1–3.8]) and TF (RR 1.8 [95% CI 1.1–2.9]) cartilage damage worsening 2 years later compared to those with the highest step rate. Men with the lowest step rate had increased risk of medial TF cartilage damage worsening 2 years later (RR 2.1 [95% CI 1.1–3.9]). Conclusion: Lower step rate was associated with increased risk of cartilage damage worsening in the lateral PF and TF compartments in women and worsening medial TF joint damage in men. Future research is necessary to understand the influence of step rate manipulation on joint biomechanics in women and men.