The lateral compartment in knees with isolated medial and patellofemoral osteoarthritis: a histologic analysis of articular cartilage.
ABSTRACT The purpose of this study was to examine, at a histologic level, the articular cartilage of the radiographically normal lateral compartment in knees with isolated medial and possibly patellofemoral osteoarthritis. Twenty patients with radiographic evidence of medial compartment osteoarthritis and a radiographically osteoarthritis-free lateral compartment underwent a tricompartmental total knee arthroplasty. The resected lateral femoral condyle and lateral tibial plateau were evaluated by a fellowship-trained musculoskeletal pathologist for the presence, or lack thereof, of osteoarthritis at a microscopic level. Both the tibia and femur showed evidence of mild osteoarthritis at a microscopic level. This study shows that in patients with radiographic evidence of medial osteoarthritis and a radiographically normal lateral compartment, there is mild osteoarthritis in the lateral compartment.
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ABSTRACT: BACKGROUND: One of the causes of failure after unicompartmental knee arthroplasty (UKA) for varus osteoarthritis is the progression of osteoarthritis in the lateral compartment. Bone formation within the articular cartilage has been reported as a possible cause of the deterioration of the osteoarthritis. However, its prevalence and histology are still uncertain. The purpose of the current study is to investigate bone pieces obtained from the lateral compartment of the knee during total knee arthroplasty (TKA) radiographically and histopathologically, and to examine the bone formation within the articular cartilage in detail. METHODS: Thirty-four consecutive patients, who underwent TKA for varus osteoarthritis of the knee, were included in this study. There were 6 males and 28 females and the mean age at the surgery was 74 years (range 63-85 years). Fifty-seven and 99 sagittal slabs were acquired from the resected bone pieces of the distal lateral femoral condyle and lateral tibial plateau, respectively. These slabs were investigated by soft X-ray radiographs and histopathological analyses stained with hematoxylin-eosin and elastica-Masson. RESULTS: On soft X-ray radiographs, bone formation (in which bone trabeculae were clearly detected) within the articular cartilage was observed in 8 (14.0 %) of 57 femoral slabs and 7 (7.1 %) of 99 tibial slabs. Histopathological analyses revealed that the bone which had formed comprised normal trabeculae and fatty marrow. There was rich vascularity in the cartilage around the formed bone. CONCLUSIONS: The current study is the first to describe the prevalence, location, and histopathological findings of bone formation within the articular cartilage of the lateral compartment of varus osteoarthritic knees. Since the thickness of the cartilage covering the bone formation is less than that without it, it may result in the deterioration of the lateral compartment after UKA.Journal of Orthopaedic Science 04/2013; · 0.96 Impact Factor
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ABSTRACT: PURPOSE: To evaluate whether medial open wedge high tibial osteotomy (HTO) results in structural changes in the articular cartilage in the lateral tibiofemoral compartment of adult sheep. METHODS: Three experimental groups received biplanar osteotomies of the right proximal tibiae: (a) closing wedge HTO (4.5° of tibial varus), (b) opening wedge HTO (4.5° tibial valgus; standard correction), and (c) opening wedge HTO (9.5° of valgus; overcorrection), each of which was compared to the contralateral knees that only received an arthrotomy. After 6 months, the macroscopic and microscopic characteristics of the articular cartilage of the lateral tibiofemoral compartment were assessed. RESULTS: The articular cartilage in the central region of the lateral tibial plateau in sheep had a higher safranin O staining intensity and was 4.6-fold thicker than in the periphery (covered by the lateral meniscus). No topographical variation in the type-II collagen immunoreactivity was seen. All lateral tibial plateaus showed osteoarthritic changes in regions not covered by the lateral meniscus. No osteoarthritis was seen in the peripheral submeniscal regions of the lateral tibial plateau and the lateral femoral condyle. Opening wedge HTO resulting in both standard and overcorrection was not associated with significant macroscopic and microscopic structural changes between groups in the articular cartilage of the lateral tibial plateau and femoral condyle after 6 months in vivo. CONCLUSION: Opening wedge HTO resulting in both standard and overcorrection is a safe procedure for the articular cartilage in an intact lateral tibiofemoral compartment of adult sheep at 6 months postoperatively.Knee Surgery Sports Traumatology Arthroscopy 01/2013; · 2.68 Impact Factor