Arthritis & Rheumatism, Volume 63,
November 2011 Abstract Supplement

Abstracts of the American College of
Rheumatology/Association of Rheumatology Health Professionals
Annual Scientific Meeting
Chicago, Illinois November 4-9, 2011.


Vibratory Sense in Patients At High Risk of Knee Osteoarthritis.

Thorlund1,  Jonas B., Shakoor2,  Najia, Ageberg3,  Eva, Sandal1,  Louise F., Block2,  Joel A., Roos1,  Ewa M.

Research Unit for Musculoskeletal Function and Physiotherapy, Institute of Sports Science and Clinical Biomechanics, University of Southern Denmark, Odense, Denmark
Rush University Medical Center, Chicago, IL
Department of Health Sciences, Lund University, Lund, Sweden

Background/Purpose:

Patients with knee osteoarthritis (OA) have impaired proprioception and vibratory sense. Vibratory sense is a separate yet closely related sensory pathway to proprioception, but is able to be more reliably tested than proprioception. It remains unclear if sensory deficits, which may alter neuromuscular activity and affect mechanical knee joint load, precede or follow as a consequence of OA. Young patients with previous anterior cruciate ligament injury are at high risk of knee OA. Furthermore, middle-aged patients with degenerative meniscus tears are suggested to be at high risk of knee OA or have early changes of knee OA. As such, they represent two distinctly different groups of patients to study early factors involved in OA pathogenesis. The aim of this study was to investigate the hypothesis that patients at high risk or with very early changes of knee OA would already display characteristic OA sensory deficits compared with age-matched controls.

Methods:

Patients: 39 ACL injured patients (ACL) (24.0±5.2 yrs, BMI 24.0±2.9 kg/m2, time since injury 21.9±21.6 month) were compared with 28 controls (ACL-C) (25.6±4.4 yrs, BMI 23.6±2.2 kg/m2). Furthermore, 22 patients meniscectomized for a degenerative tear (APM) (49.6±4.8 yrs, BMI 24.7±2.7 kg/m2, time since surgery 49.6±5.0 month) were compared with 25 controls (APM-C) (49.4±5.2 yrs, BMI 25.2±4.9 kg/m2).

Self-reported outcomes: The Knee Injury and Osteoarthritis Score (KOOS) was used to assess knee-related pain, symptoms, function in daily life (ADL), sports and recreation function (Sport/Rec) and quality of life (QOL). Separate subscale scores from 0 to 100, worst to best, were calculated.

Vibratory perception threshold (VPT): VPT was assessed using a biothesiometer at two different sites (i.e. the most prominent point of the medial malleolus (MM) and the medial femoral condyle MFC)). The mean of two measurements was noted as the VPT (i.e. higher value indicates worse vibration sense).

Results:

ACL self-reported substantially worse than ACL-C on all KOOS subscales (p<0.001). APM self-reported worse QOL (p=0.007) than APM-C and a tendency for more pain (p=0.079) and symptoms (p=0.084) than controls. No difference was observed between APM and APM-C in ADL and Sport/Rec. In contrast, no evidence of somatosensory deficit was observed in either the ACL or the APM group. Linear regression (adjusting for age and sex) showed no sign of sensory deficits (i.e. increased VPT score) in ACL compared with ACL-C at either of the two sites (MM: 9.4 (8.6 – 10.3) vs. 11.0 (9.7 – 12.3) volts, p=0.034 MFC: 15.7 (14.0 – 17.5) vs. 18.1 (15.8 – 20.4), p=0.122 in the patients and controls, respectively) or in APM compared with APM-C (MM: 14.4 (12.2 – 16.6) vs. 16.6 (13.6 – 19.6), p=0.182 MFC: 18.9 (15.9 – 21.9 vs. 23.0 (19.3 – 26.8), p=0.092 in the patients and controls, respectively).

Conclusion:

These data do not support the hypothesis that sensory deficits precede overt OA in post-traumatic OA, at least in young ACL-injured patients and middle-aged meniscectomized patients at high risk or in the very early phase of knee OA. Further study is necessary to distinguish the time course of somatosensory loss in OA.

To cite this abstract, please use the following information:
Thorlund, Jonas B., Shakoor, Najia, Ageberg, Eva, Sandal, Louise F., Block, Joel A., Roos, Ewa M.; Vibratory Sense in Patients At High Risk of Knee Osteoarthritis. [abstract]. Arthritis Rheum 2011;63 Suppl 10 :1088
DOI:

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