Basic Research

Clinical Orthopaedics and Related Research®

, 469:2866

First online:

Are Joint Structure and Function Related to Medial Knee OA Pain? A Pilot Study

  • Rebecca Avrin ZifchockAffiliated withLeon Root, MD Motion Analysis Laboratory, Department of Rehabilitation, Hospital for Special Surgery
  • , Yatin KiraneAffiliated withLeon Root, MD Motion Analysis Laboratory, Department of Rehabilitation, Hospital for Special Surgery Email author 
  • , Howard HillstromAffiliated withLeon Root, MD Motion Analysis Laboratory, Department of Rehabilitation, Hospital for Special Surgery
  • , The Hospital for Special Surgery Lower Extremity Realignment Research GroupAffiliated withLeon Root, MD Motion Analysis Laboratory, Department of Rehabilitation, Hospital for Special Surgery

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Abstract

Background

Although the severity of knee osteoarthritis (OA) usually is assessed using different measures of joint structure, function, and pain, the relationships between these measures are unclear.

Purpose

Therefore, we: (1) examined the relationships between the measures of knee structure (flexion-extension range of motion, radiographic tibiofemoral angle, and medial joint space), function (Knee Osteoarthritis Outcome Scores [KOOS], peak adduction angle, and moment), and pain (visual analog scale [VAS]); and (2) identified variables that best predicted knee pain.

Methods

We assessed 15 patients with medial knee OA using VAS pain, KOOS questionnaire, 3-D gait analysis, and radiographic examination. Parameter relationships were assessed using Pearson correlation, and variables most predictive of knee pain were determined using a stepwise multiple regression.

Results

Subjective measurements correlated (|r| ≥ 0.54) with one another, as did most of the objective measurements (|r| ≥ 0.56) except for adduction moment which did not correlate with any variable. All variables correlated (|r| > 0.54) with VAS knee pain except peak adduction moment. Medial joint space and peak adduction angle best predicted knee pain, accounting for approximately three-quarters of the model variance (r2 = 0.73).

Conclusions

Medial joint space and peak adduction angle may be useful for predicting knee pain in patients with medial knee OA. Therapies that target these structural and functional variables may reduce knee pain in this population.

Clinical Relevance

Increasing the medial joint space and limiting the peak knee adduction angle may be critical in achieving effective pain relief in patients with varus knee OA.