Patterns of patellofemoral articular cartilage wear in Japanese cadavers

Morphological analysis of three-dimensional MR images of patellofemoral joints in asymptomatic subjects

The existing methods for analyzing patellofemoral (PF) osteoarthritis (OA) are limited. Our purpose was to clarify the frequency, localization, and morphological progression of PFOA by observing three-dimensional (3D) magnetic resonance (MR) images from a cohort population. The subjects were 561 patients aged 30-79 years from the Kanagawa Knee Study who had not visited a hospital for more than three consecutive months for knee symptoms. MR images of the PF joints, separated into the medial and lateral types, were presented in order of the highest to lowest patella cartilage area ratios. Cartilage defects in the patella were detected in 37 subjects (6.6%). Medial lesions (4.6%) were significantly more frequent than lateral lesions (2.0%) (p < 0.01). For both medial and lateral lesions, the patellar cartilage defects were divided into confined and unconfined types. The 3D MR images of the PF joint showed that the patellar cartilage defect occurred along each ridge of the femoral trochlea. The 3D MR images revealed a 6.6% prevalence of patellar cartilage defects, higher in the medial than lateral regions. The 3D MR images can easily determine PF morphology and cartilage defect location, making them useful in understanding the pathophysiology and etiology of PFOA.

High Prevalence of Isolated Antero-medial Osteoarthritis (AMOA) in Indian Patients Undergoing Primary Total Knee Arthroplasty

Background

Isolated antero-medial osteoarthritis (AMOA) of the knee is a distinct pattern of arthritis. Medial arthritis of the knee in select patients can be managed with uni-compartmental arthroplasty (UKA), with studies showing shorter hospital stay, faster rehabilitation and reduced medical complications in the post-operative period compared to TKA. However, the prevalence of AMOA in Indian patients with osteoarthritis of the knee is unknown. The aim of this study was to evaluate the prevalence of AMOA in patients undergoing primary TKA for OA.

Methods

This was a prospective evaluation of 2518 knees in 1936 patients who were selected for primary TKA. Pre-operative radiographs were screened based on the Oxford UKA Radiological decision aid and diagnosis of AMOA was established. All 2518 knees underwent primary total knee arthroplasty and cases of AMOA were confirmed intra-operatively based on ACL integrity, lateral compartment wear and medial compartment wear pattern. Cases with AMOA arthritic wear pattern were considered amenable for UKA if radiographs showed intact lateral joint space, intra-operatively those with intact and functional ACL, acceptable patellofemoral wear (Outerbridge I-II).

Results

We report a prevalence of 46.94% of AMOA, who were amenable for UKA. Obese patients were more likely to have a damaged or non-functional ACL and more likely to have a high degree of wear, not amenable for UKA (p < 0.05). Non-functional ACL was associated with higher prevalence of posterior extension of arthritic wear.

Conclusion

This study demonstrated a high prevalence (46.94%) of antero-medial osteoarthritis (AMOA), amenable for UKA. Patient selection is important for improving outcomes after TKA or UKA. Future studies are warranted to compare outcomes of both UKA and TKA in patients with isolated AMOA of the knee.