52 – Disorders of the inert structures: Capsular and non-capsular patterns

Fourteen knees were studied by a method called spatial location, to determine the contact and load-bearing areas between the femur and the upper tibia in non-loaded and loaded conditions, at various angles of flexion. Under no load, contact occurred primarily on the menisci; the lateral aspects contacted at 0 degrees flexion, moving to the posterolateral aspects at 90 degrees flexion. An area of cartilage which frequently contacted was the medial tibial spine. Under loads of up to 150 kg, the lateral meniscus appeared to carry most of the load on that side of the joint, while on the medial side, the load was shared approximately equally by the meniscus and the exposed cartilage. These findings were verified on two knees by measuring contact pressure with a miniature transducer. Two implications of these findings are that the area of load-bearing is greatly increased and that the stability of the knee joint is enhanced by the menisci.

The role of the menisci in force transmission across the knee.

A radiolucent lesion in the medial femoral condyle was observed in 40 knees in 39 patients over age 60. Most patients had had spontaneous onset of severe knee pain. Twelve knees were radiographically normal within 2 months following onset of pain. Seven knees proceeded to osteoarthritis whereas others became rather asymptomatic. Strontium-85 scintimetry of symptomatic knees showed exceedingly high values. Biopsy showed evidence of repair of bone tissue. The condition was identified as osteonecrosis, the natural history and management of which were discussed. Only 2 patients had a history of systemic adrenocorticosteroid treatment; no other conditions commonly associated with osteonecrosis were identified.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/art.1780110602

Spontaneous Osteonecrosis of the Knee

Purpose: To prospectively evaluate the association between clinical features and structural abnormalities found at magnetic resonance (MR) imaging in patients with osteoarthritis (OA) of the knee. Materials and Methods: The study was approved by the institutional medical ethics review board. Written informed consent was obtained from each patient. MR images of the knee were obtained from 205 (42 [20%] men, 163 [80%] women; median age, 60 years; range, 43–77 years) patients in whom symptomatic OA at multiple joint sites was diagnosed. MR images were analyzed for various abnormalities of OA. All patients were interviewed concerning pain and stiffness in the knee that was imaged. Odds ratios (ORs) with 99% confidence intervals (CIs) were used to determine the association between the imaging findings and clinical features of OA. Results: A large joint effusion was associated with pain (OR, 9.99; 99% CI: 1.28, 149) and stiffness (OR, 4.67; 99% CI: 1.26, 26.1). The presence of an osteophyte in the patellofemora...

/pdf/osteoarthritis-of-the-knee-association-between-clinical-2cm8k4tnfg.pdf

Osteoarthritis of the knee: association between clinical features and MR imaging findings.

Osteochondritis dissecans of the knee is being seen with increased frequency in pediatric and young adult athletes and is thought to be, in part, owing to earlier and increasingly competitive sports participation. Despite much speculation, the cause of both juvenile and adult osteochondritis dissecans remains unclear. Early recognition is essential. Whereas adult osteochondritis dissecans lesions have a greater propensity to instability, juvenile osteochondritis dissecans lesions are typically stable, and those with an intact articular surface have a potential to heal with nonoperative treatment through cessation of repetitive impact loading. The value of adjunctive immobilization, protected weightbearing, and unloader bracing has not been established. Skeletally immature patients with stable lesions that have not healed with nonoperative treatment should have consideration given to arthroscopic drilling to promote healing before the lesion progresses and requires more involved treatment with a less optimistic prognosis. Magnetic resonance imaging may allow early prediction of lesion healing potential. The majority of adult osteochondritis dissecans cases as well as those skeletally immature patients with unstable lesions and secondary loose bodies require fixation and possible bone grafting. Many unstable lesions will heal after stabilization, but long-term prognosis is not clear. Chronic loose fragments can be difficult to fix and have poor healing potential. Results of excision of large lesions from weightbearing zones are poor. Chondral resurfacing techniques have limited long-term data for cases of osteochondritis dissecans in skeletally immature patients.

52 – Disorders of the inert structures: Capsular and non-capsular patterns

References

The role of the menisci in force transmission across the knee.

Spontaneous Osteonecrosis of the Knee

Osteoarthritis of the knee: association between clinical features and MR imaging findings.

Management of Osteochondritis Dissecans of the Knee: Current Concepts Review

Viscosupplementation with hylan G-F 20: a 26-week controlled trial of efficacy and safety in the osteoarthritic knee.