2015 ISAKOS Biennial Congress ePoster #1922

Factors Associated With Grade 4 Chondral Defects of the Patellofemoral Joint

J. Richard Steadman, MD, Vail, CO UNITED STATES
Karen K. Briggs, MPH, MBS, Vail, CO UNITED STATES
Lauren M. Matheny, BA, Vail, CO UNITED STATES
William G. Rodkey, DVM, Dipl ACVS, Edwards, CO UNITED STATES

Steadman Philippon Research Institute, Vail, CO, USA

FDA Status Not Applicable

Summary: Grade 4 chondral defects are common and disability is increased with they occur in association with patella subluxation and/or malalignment.

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Abstract:

Introduction

Patellofemoral (PF) cartilage damage can cause severe knee pain and result in increasing disability. The purpose of this study was to identify factors associated with grade 4 (G4) chondral defects of the patello-femoral joint.

Methods

A cohort of 1374 patients (average age=48, range, 18 to 83) who underwent knee arthroscopy for knee pathology were studied prospectively. All patients had complete demographic data, surgical data, WOMAC and Lysholm scores, and health status (SF12) collected at initial exam and stored in a data registry. All consecutive patients undergoing knee arthroscopy by a single surgeon were included. Patients less than 18 years of age were excluded.

Results

G4 cartilage defects were seen in 634 knees (46%). PF G4 chondral defects were seen in 359 knees (26%), with 83 patellar (PAT) defects, 166 trochlear groove (TG) defects and 110 combined PAT and TG defects. 79 patients with PF G4 defects also had medial compartment G4 chondral defects and 94 patients with PF G4 chondral defects had lateral compartment G4 chondral defects. PF G4 defects were not associated ligament or meniscus injuries. Patients with PAT malalignment and/or subluxation (MAL/SUB) were 2 times more likely to have PF defects compared to those without MAL/SUB [95%CI:1.2 to 3.5]. In the subgroup of patients with PF defects, patients with PAT G4 defects had significantly more pain than patients with trochlea G4 defects(p=0.023); however, no other scores were different. Patient with PAT MAL/SUB were more likely to have PAT (p=0.001) and TG grade 4 defects (p=0.006) compared to those without MAL/SUB. These patients also had significantly lower physical component quality of life(p=0.001), increased pain(p=0.001), increased disability(WOMAC)(0.043), and decreased function (Lysholm)(p=0.041) compared to those without PAT MAL/SUB.

Conclusions

This study confirms that G4 defects of the PF compartment are common. They often occur with chondral defects in other compartments; however, they are not associated with ligament or meniscus injuries. PAT and TG patients often present with similar disability and loss of function; however, patients with PAT G4 defects do experience more pain. PF G4 defects are associated with patella malalignment and/or subluxation, which increases the disability seen in these patients. If a patient presents with PAT MAL/SUB, there should be a higher suspicion of PF G4 defects at arthroscopy. This observation may improve early diagnosis, preoperative planning and patient education. These data confirm the importance of new treatment strategies for chondral defects of the patellofemoral compartment, with special attention to alignment and stability of the patella.