Unicompartmental Knee Arthritis: Knee Bracing

Rajiv Gandhi, M.D., FRCSC
Nizar Mahomed, M.D., FRCSC
Toronto, ON

The knee is the joint most affected by osteoarthritis and varus alignment is its most common deformity1. Conservative treatment options include weight loss, pain medicines, intra-articular injections, lateral heel wedges, and bracing. Bracing options include valgus-unloader braces or simple neoprene sleeves.

Evaluation of the unloader brace has shown that it may decrease the adduction moment at the knee during gait thereby decreasing the forces across the medial compartment2. In a fluoroscopic study, the authors show that condylar separation can be achieved through the medial compartment with unloader bracing3. They also concluded that the condylar separation was less in obese patients with whom brace fixation was difficult to obtain. The neoprene sleeves likely provide little mechanical support to the knee but instead may lead to decreased pain and better function through improved sense of proprioception4.

In the literature there currently exists three randomized controlled trials comparing valgus-unloader brace treatment with medical treatment only. The first is a randomized crossover study of 40 patients which concluded that valgus brace treatment showed only a modest improvement in pain that was not statistically significant5. This study did not provide a power calculation and likely had an insufficient sample to detect a clinically significant difference. Moreover, the major limitation of the crossover design is the carryover effect where the effect of the first treatment still may be present into the period of the second treatment.

The second study randomized 119 patients into three arms: 1) valgus-unloader brace, 2) neoprene sleeve, or 3) medical therapy only. These authors concluded that both bracing groups showed a substantially greater improvement in quality of life scores as compared to the control group (p<0.001). As compared to neoprene sleeves, the valgus-unloader brace group demonstrated significantly less pain on the six minute walking test (p=0.021) and on the 30 second stair climbing test (p=0.016), and a strong trend towards a significant improvement on the total WOMAC score (p=0.06)4.

The third study randomized 117 patients who had isolated medial or lateral compartment arthritis into two groups: one group was treated with medical therapy and a varus or valgus-unloader brace as appropriate, and the second group was treated with medical management alone. For their primary outcome of pain severity and knee function scores, they reported a strong trend towards a beneficial effect of bracing over medical management alone at three, six, and 12 months follow-up (p<0.1). The brace group did report significantly improved walking distances as compared to the control group at all points of follow-up (p<0.05). The authors concluded that brace treatment offers a small additional beneficial effect in knee OA as compared to medical management alone6.

Draganich et al performed a crossover study of ten patients, and compared the use of custom fit valgus-unloader bracing with off the shelf patient-adjustable valgus bracing7. These authors concluded that both braces significantly reduced pain and stiffness as compared to no bracing (p<0.05). The custom fit bracing also demonstrated a significant benefit in reducing pain and stiffness, improving function, and decreasing the peak external adduction moment during gait as compared to the off the shelf braces (p<0.05). Other authors have also found a significant decrease in pain, stiffness and peak external adduction moment with the use of valgus-unloader bracing8.

In a biomechanical study, Ramsey et al attempted to determine the mechanism by which valgus-unloader bracing leads to pain relief in varus gonarthrosis9. Through gait and motion analysis, the authors concluded that the pain relief is mediated through the reduction in muscle co-contractions rather than condylar separation, as neutral alignment produced the same pain relief as valgus alignment. The hypothesis put forward is that the brace limits functional instability of the knee, which decreases the muscle co-contractions of the vastus lateralis and medialis and thereby decreasing joint contact pressures9.

In conclusion, the best available evidence indicates that valgus-unloader bracing, in addition to medical management, is effective at relieving pain at short-term follow-up when compared to medical management alone. Its use appears limited by the ability to fit the brace on obese limbs and patient compliance with the brace. The beneficial effects of bracing are likely mediated through compartment unloading, improved proprioception, and a decrease in the adduction moment arm and muscle co-contraction.

References

  1. 1. Wilson, M. G.; Michet, C. J., Jr.; Ilstrup, D. M.; and Melton, L. J., III. Idiopathic symptomatic osteoarthritis of the hip and knee: a population-based incidence study. Mayo Clin. Proc., 1990 65: 1214-1221,.
  2. Lindenfeld, T. N.; Hewett, T. E.; and Andriacchi, T. P. Joint loading with valgus bracing in patients with varus gonarthrosis. Clin. Orthop, 1997 344: 290-297.
  3. Dennis D.A., Richard D. Komistek R.D., Nadaud M.C., Mahfouz M. Evaluation of Off-Loading Braces for Treatment of Unicompartmental Knee Arthrosis. J Arthroplasty 2006; 21(4 Suppl 1): 2-8.
  4. Kirkley A., Webster-Bogaert S., Litchfield R., Amendola A., Macdonald S., McCalden R.J., Fowler P. The effect of bracing on varus gonarthrosis. J Bone Joint Surg Am. 1999; 81:539-48.
  5. Horlick S.G., Loomer, R. L. Valgus knee bracing for medial gonarthrosis. Clin. J. Sport Med. 3: 251-255, 1993.
  6. Brouwer R.W., van Raaij T.M., Verhaar J.A., Coene L.N., Bierma-Zeinstra S.M.A. Brace treatment for osteoarthritis of the knee: a prospective randomized multi-centre trial. Osteoarthritis Cartilage. 2006 Aug; 14(8): 777-83
  7. Draganich L., Reider B., Rimington T. Piotrowski G., Mallik K., Nasson S. The effectiveness of Self-Adjustable custom and off-the-shelf bracing in the treatment of varus gonarthrosis. J Bone Joint Surg Am. 2006; 88: 2645-2562.
  8. Lindenfeld T.N., Hewett T.E., Andriacchi T.P. Joint Loading with valgus bracing in patients with varus gonarthrosis. Clin Orthop Relat Res. 1997; 344: 290-297.
  9. Ramsey D.K., Briem K., Axe M.J., Snyder-Mackler L. A mechanical theory for the effectiveness of bracing for medial compartment osteoarthritis of the knee. J Bone Joint Surg Am. 2007; 89: 2398-2407.

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