Dervan rim sign new, simple radiological sign for unique Indian medial femoral condylar osteoarthritis

Abstract

Introduction: OA knee is most common form of arthritis in Asian population. The medial compartment of knee is most commonly involved. Most X-ray studies have been from the Western Caucasian patients with different genetic pool, habitus and lifestyle. The accepted norm for surgical intervention like unicondylar knee replacement or High Tibial Osteotomy is bone on bone Arthritis which has simultaneous affection of both medial Tibial & Femoral compartments. We however noted a different radiological pattern also causing severe pain on medial side of knee, without bone on bone arthritis. This was labeled DERVAN RIM SIGN. Materials and Method: This pilot Study describes a new radiological sign based on standard Anteroposterior Xray of knee joint, taken in standing weight bearing position with toes and patella pointing forwards in 15 degrees of flexion. The findings of this sign and correlation to selective medial condylar femoral cartilage loss in 25 patients are confirmed with 1 MRI of knee joint 17 patients 2 Arthroscopy of knee joint 3 patients 3 Open Arthrotomy during Unicondylar knee Arthroplasty 5 patients Results: 100 percent correlation is seen in all 25 cases between the Dervan RIM sign & Eburnation and loss of Medial femoral cartilage in the three modalities of visual confirmation viz MRI, Arthroscopy or Visual examination in open surgery. Mild involvement of the Tibial condyle was noted in all cases and this was the cause of absence of bone on bone Arthritis.

Is Indian osteoarthritis different? Emerging scenarios of disease pattern and implications for diagnosis and treatment of osteoarthritis in India

“…As highlighted in above results, there is strong correlation between presence of medial femoral and tibial condyle cartilage loss and presence of radiological rim sign. 13 In our study, it has been observed that there is a difference in the cartilage loss pattern between those patients of Indian ethnicity and that of the Caucasian population. A study by Forbell et al suggests that there is more loss of cartilage over medial tibial condyle as compared to femoral condyle in the Caucasian population.…”

“…In the cartogram, femoral and tibial wear was measured and in the antero-posterior knee radiographs, we measured the height of the "Dervan rim sign" (femoral cartilage loss and tibial cartilage loss). 13 The findings were then tabulated. And microsoft excel was used to compute data and calculate value accordingly.…”

Dervan simultaneous surgical protocol complete relief of lower limb neuralgic & arthritic pain

“…Site of pain The newly described Dervan Rim Sign was an important tool to note non bone on bone medial compartment arthritis and explain cause of non-bone on bone contact arthritic pain [7] . Counselling, planning & explaining surgical protocol, Rehabilitation as per the Dervan Protocol [8] .…”