A Prospective Pilot Study Comparing Diagnostic Knee Needle Arthroscopy (NA) With Standard Weight Bearing Knee Radiographic in Predicting Unicompartmental Knee Osteoarthritis Prior to Unicompartmental Knee Arthroplasty

A prospective study of patients being evaluated for UKA/TKA will be performed. The study will include two groups: 1) patients who are diagnosed with isolated unicompartmental knee OA by standard weight bearing radiographs and are likely indicated for UKA and 2) patients for whom the standard weight bearing radiographs are equivocal for the diagnosis of unicompartmental OA vs. tricompartmental OA. The preoperative radiographic evaluation prior to UKA or TKA includes a series of standard weight bearing knee radiographs which historically have been used to differentiate between unicompartmental OA and tricompartmental OA. This series of radiographs includes weight bearing AP, lateral, skyline, Rosenberg, and valgus stress views.

Subsequently, after obtaining informed consent, both groups of patients will undergo NA, performing in the operating room on the day of arthroplasty, prior to surgery beginning. NA will be performed with a 1.9mm nano arthroscope, as part of their diagnostic pre-arthroplasty evaluation, in lieu of standard arthroscopy, which utilizes a 4.8mm arthroscope. NA will directly visualize the articular cartilage in the medial, lateral, and patellofemoral compartments of the knee. Cartilage will be arthroscopically graded according to the Outerbridge Classification of chondral lesions. Patients with visualized Grade IV full-thickness cartilage loss with exposed subchondral bone isolated to either the medial or lateral compartment, with Grade 0-II lesions in the contralateral and / or patellofemoral compartments, will undergo a medial or lateral UKA, respectively. Patients with a Grade IV lesion in the medial or lateral compartment, with asymptomatic Grade III lesions in the contralateral and / or patellofemoral compartments will undergo a medial or lateral UKA, respectively. Patients with a Grade IV lesion in the medial or lateral compartment, with symptomatic Grade III lesions in the contralateral and / or patellofemoral compartments will undergo TKA. Patients with a Grade IV lesion in the medial or lateral compartment, with Grade IV lesions in the contralateral and / or patellofemoral compartments will undergo TKA.

Intraoperative findings at the time of arthroplasty will serve at the gold standard to which the NA findings will be compared. Furthermore, the diagnosis obtained from NA will be compared to the diagnosis obtained from preoperative weight bearing radiographs.