X. Wang

Cartilage morphology at 2–3 years following anterior cruciate ligament reconstruction with or without concomitant meniscal pathology

PurposeTo examine differences in cartilage morphology between young adults 2–3xa0years post-anterior cruciate ligament reconstruction (ACLR), with or without meniscal pathology, and control participants.MethodsKnee MRI was performed on 130 participants aged 18–40xa0years (62 with isolated ACLR, 38 with combined ACLR and meniscal pathology, and 30 healthy controls). Cartilage defects, cartilage volume and bone marrow lesions (BMLs) were assessed from MRI using validated methods.ResultsCartilage defects were more prevalent in the isolated ACLR (69xa0%) and combined group (84xa0%) than in controls (10xa0%, Pxa0<xa00.001). Furthermore, the combined group showed higher prevalence of cartilage defects on medial femoral condyle (OR 4.7, 95xa0% CI 1.3–16.6) and patella (OR 7.8, 95xa0% CI 1.5–40.7) than the isolated ACLR group. Cartilage volume was lower in both ACLR groups compared with controls (medial tibia, lateral tibia and patella, Pxa0<xa00.05), whilst prevalence of BMLs was higher on lateral tibia (Pxa0<xa00.001), with no significant differences between the two ACLR groups for either measure.ConclusionsCartilage morphology was worse in ACLR patients compared with healthy controls. ACLR patients with associated meniscal pathology have a higher prevalence of cartilage defects than ACLR patients without meniscal pathology. The findings suggest that concomitant meniscal pathology may lead to a greater risk of future OA than isolated ACLR.Level of evidenceIII.

Greater magnitude tibiofemoral contact forces are associated with reduced prevalence of osteochondral pathologies 2–3 years following anterior cruciate ligament reconstruction

PurposeExternal loading of osteoarthritic and healthy knees correlates with current and future osteochondral tissue state. These relationships have not been examined following anterior cruciate ligament reconstruction. We hypothesised greater magnitude tibiofemoral contact forces were related to increased prevalence of osteochondral pathologies, and these relationships were exacerbated by concomitant meniscal injury.MethodsThis was a cross-sectional study of 100 individuals (29.7u2009±u20096.5xa0years, 78.1u2009±u200914.4xa0kg) examined 2–3xa0years following hamstring tendon anterior cruciate ligament reconstruction. Thirty-eight participantsxa0had concurrent meniscal pathology (30.6u2009±u20096.6xa0years, 83.3u2009±u200914.3xa0kg), which included treated and untreated meniscal injury, and 62xa0participants (29.8u2009±u20096.4xa0years, 74.9u2009±u200913.3xa0kg) were free of meniscal pathology. Magnetic resonance imaging of reconstructed knees wasxa0used to assess prevalence of tibiofemoral osteochondral pathologies (i.e., cartilage defects and bone marrow lesions). A calibrated electromyogram-driven neuromusculoskeletal model was used to predict medial and lateral tibiofemoral compartment contact forces from gait analysisxa0data. Relationships between contact forces and osteochondral pathology prevalence were assessed using logistic regression models.ResultsIn patients with reconstructed knees free from meniscal pathology, greater medial contact forces were related to reduced prevalence of medial cartilage defects (odds ratio (OR)u2009=u20090.7, Wald χ2(2)u2009=u20097.9, 95% confidence interval (CI)u2009=u20090.50–95, pu2009=u20090.02) and medialxa0bone marrow lesions (ORu2009=u20090.8, Wald χ2(2)u2009=u20094.2, 95% CIu2009=u20090.7–0.99, pu2009=u20090.04). No significant relationships were found in lateral compartments. In reconstructed knees with concurrent meniscal pathology, no relationships were found between contact forces and osteochondral pathologies.ConclusionsIn patients with reconstructed knees free from meniscal pathology, increased contact forces were associated with fewer cartilage defects and bone marrow lesions in medial, but not, lateral tibiofemoral compartments. No significant relationships were found between contact forces and osteochondral pathologies in reconstructed knees with meniscal pathology for any tibiofemoral compartment. Future studies should focus on determining longitudinal effects of contact forces and changes in osteochondral pathologies.Level of evidenceIV.

Cartilage quantitative T2 relaxation time 2-4 years following isolated anterior cruciate ligament reconstruction: CARTILAGE T2 FOLLOWING ISOLATED ACLR

Cartilage T2 relaxation time in isolated anterior cruciate ligament reconstruction (ACLR) without concomitant meniscal pathology and their changes over time remain unclear. The purpose of this exploratory study was to: (i) compare cartilage T2 relaxation time (T2 values) in people with isolated ACLR at 2–3 years post‐surgery (baseline) and matched healthy controls and; (ii) evaluate the subsequent 2‐year change in T2 values in people with ACLR. Twenty‐eight participants with isolated ACLR and nine healthy volunteers underwent knee magnetic resonance imaging (MRI) at baseline; 16 ACLR participants were re‐imaged 2 years later. Cartilage T2 values in full thickness, superficial layers, and deep layers were quantified in the tibia, femur, trochlear, and patella. Between‐group comparisons at baseline were performed using analysis of covariance adjusting for age, sex, and body mass index. Changes over time in the ACLR group were evaluated using paired sample t‐tests. ACLR participants showed significantly higher (pu2009=u20090.03) T2 values in the deep layer of medial femoral condyle at baseline compared to controls (mean difference 4.4u2009ms [13%], 95%CI 0.4, 8.3u2009ms). Over 2 years, ACLR participants showed a significant reduction (pu2009=u20090.04) in T2 value in the deep layer of lateral tibia (mean change 1.4u2009ms [−7%], 95%CI 0.04, 2.8u2009ms). The decrease in T2 values suggests improvement in cartilage composition in the lateral tibia (deep layer) of ACLR participants. Further research with larger ACLR cohorts divided according to meniscal status and matched healthy cohorts are needed to further understand cartilage changes post‐ACLR.

Relationships Between Tibiofemoral Contact Forces and Cartilage Morphology at 2 to 3 Years After Single-Bundle Hamstring Anterior Cruciate Ligament Reconstruction and in Healthy Knees

Background: Prevention of knee osteoarthritis (OA) following anterior cruciate ligament (ACL) rupture and reconstruction is vital. Risk of postreconstruction knee OA is markedly increased by concurrent meniscal injury. It is unclear whether reconstruction results in normal relationships between tibiofemoral contact forces and cartilage morphology and whether meniscal injury modulates these relationships. Hypotheses: Since patients with isolated reconstructions (ie, without meniscal injury) are at lower risk for knee OA, we predicted that relationships between tibiofemoral contact forces and cartilage morphology would be similar to those of normal, healthy knees 2 to 3 years postreconstruction. In knees with meniscal injuries, these relationships would be similar to those reported in patients with knee OA, reflecting early degenerative changes. Study Design: Cross-sectional study; Level of evidence, 3. Methods: Three groups were examined: (1) 62 patients who received single-bundle hamstring reconstruction with an intact, uninjured meniscus (mean age, 29.8 ± 6.4 years; mean weight, 74.9 ± 13.3 kg); (2) 38 patients with similar reconstruction with additional meniscal injury (ie, tear, repair) or partial resection (mean age, 30.6 ± 6.6 years; mean weight, 83.3 ± 14.3 kg); and (3) 30 ligament-normal, healthy individuals (mean age, 28.3 ± 5.2 years; mean weight, 74.9 ± 14.9 kg) serving as controls. All patients underwent magnetic resonance imaging to measure the medial and lateral tibial articular cartilage morphology (volumes and thicknesses). An electromyography-driven neuromusculoskeletal model determined medial and lateral tibiofemoral contact forces during walking. General linear models were used to assess relationships between tibiofemoral contact forces and cartilage morphology. Results: In control knees, cartilage was thicker compared with that of isolated and meniscal-injured ACL-reconstructed knees, while greater contact forces were related to both greater tibial cartilage volumes (medial: R 2 = 0.43, β = 0.62, P = .000; lateral: R 2 = 0.19, β = 0.46, P = .03) and medial thicknesses (R 2 = 0.24, β = 0.48, P = .01). In the overall group of ACL-reconstructed knees, greater contact forces were related to greater lateral cartilage volumes (R 2 = 0.08, β = 0.28, P = .01). In ACL-reconstructed knees with lateral meniscal injury, greater lateral contact forces were related to greater lateral cartilage volumes (R 2 = 0.41, β = 0.64, P = .001) and thicknesses (R 2 = 0.20, β = 0.46, P = .04). Conclusion: At 2 to 3 years postsurgery, ACL-reconstructed knees had thinner cartilage compared with healthy knees, and there were no positive relationships between medial contact forces and cartilage morphology. In lateral meniscal-injured reconstructed knees, greater contact forces were related to greater lateral cartilage volumes and thicknesses, although it was unclear whether this was an adaptive response or associated with degeneration. Future clinical studies may seek to establish whether cartilage morphology can be modified through rehabilitation programs targeting contact forces directly in addition to the current rehabilitation foci of restoring passive and dynamic knee range of motion, knee strength, and functional performance.