Unloader brace significantly benefits osteoarthritis of the knee

Investigators also find that education aids in brace use compliance.

A prospective cohort study found that patients with osteoarthritis, who have high expectations of improving their ability to participate in recreational sports, had improvement in their disability when using an unloader brace.

Össur Unloader One

by Bob Kronemyer, Healio Orthopedics Today May 2010

“Patients maintained or improved their activity level and saw reduction in pain and anti-inflammatory medications,” said co-investigator Karen K. Briggs MPH, director of clinical research at the Steadman Philippon Research Institute in Vail, Colorado. Her comments came during the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons in New Orleans.

For the study, 47 patients, 17 women and 29 men, with a mean age of 61 years were fitted with unloader braces (Össur Unloader One), 14 patients with a lateral unloader, and 32 with a medial unloader.

High expectations
“Previous studies have shown that unloader braces resulted in improvement in disability due to osteoarthritis,” Briggs told Orthopedics Today. “However, few studies have looked at active patients with osteoarthritis seeking to improve function and activity level. In our study, we showed that patients can improve their activity and their function with an unloader brace — in a population who had high expectations regarding activity.”

The study found similar improvement in both types of braces. The larger medial group, though, had increased disability prior to brace use and more improvement.

“But the smaller the medial joint space, the more disability in the medial group,” Briggs said. The lateral group showed increased disability in patients with more varus alignment.

All patients completed the Western Ontario and McMaster Universities (WOMAC) Osteoarthritis Index prior to brace use, then at 6-week and 6-month follow-up. The medial group had a higher pre-brace total WOMAC (34 vs. 23). Pre-brace pain was also greater in the medial group (8 vs. 5).

Improved WOMAC
The mean medial joint space for the medial group was 2.4 mm, compared to a mean lateral joint space of 4.2 mm for the lateral group.

“It was interesting that for the medial group, the pre-brace WOMAC score correlated with medial joint space,” Briggs said. “The less medial joint space, the more disability. The lateral group disability did not correlate with joint space loss, however, the joint space was measured on AP radiographs which does not assess loss of joint space in the posterior portion of the lateral compartment.”

There was also a 26% deviation from neutral alignment in the medial group and 19% in the lateral group. “For the lateral group, pre-brace WOMAC correlated with deviation from neutral alignment,” Briggs said. “More research is needed to determine the difference between patient disability in the varus and valgus knee.”

At 6 months, improvement in WOMAC was 12 points for the medial group and 9 points in the lateral group, “for close to a 50% improvement in disability,” she said.

QOL scores
Patients also had expectations of improvement in quality of life. This was measured using the SF-12. “The physical component of the SF-12 showed significant improvement at 6 weeks and 6 months,” Briggs said. “As expected, the mental component did not change.”

Overall, patients were satisfied with their treatment. “We feel it is important to document all these measures,” Briggs said. “If patient expectations can be met, then patients will be more satisfied with their treatment.”

Briggs also noted that the study had a high level of continued brace use. “It is our opinion that the low drop-out rate is due to patient education and proper fitting of the brace initially,” she said.

Perspective
The study shows that patient education, and compliance makes the use of an unloader brace successful for the treatment of medial and lateral knee osteoarthritis. In it, the more the medial joint space narrowing, the more the pre-brace disability. The results showed that the unloader brace had a 50% improvement in disability.

There is no question that to make the use of unloader brace successful several criteria must be met. The patient must be very motivated to use a brace and this may be improved by patient education. Not every patient is convinced that they want to wear a brace for all activities. Many patients would rather have an operation than use a brace. Therefore there is probably some selection bias in any brace study.

The other criteria that are important are the size of the thigh, and medial pseudo-laxity. It is very difficult to fit a brace to a conical thigh. The lean active patient is much more likely to continue with brace use. I have found that the patient who has medial pseudo-laxity compared to a fixed varus knee will respond better to unloader bracing.

Finally, the company that supplied the brace supported this study.

Thus there are several selection bias that are evident in this study by Briggs, which should be recognized, but do not reduce the significance of the findings.

Donald H. Johnson MD FRCSC, Sports Medicine Clinic, Carleton University, Ottawa, Ontario

Use of an unloader brace for medial or lateral compartment osteoarthritis of the knee, Briggs KK, Matheny LM, Steadman JR, Aultman H. Paper 638. Presented at the 2010 Annual Meeting of the American Academy of Orthopaedic Surgeons. March 9-13. New Orleans.

Karen K. Briggs MPH, director of clinical research, Steadman Philippon Research Institute, 181 W. Meadow Drive, Suite 1000, Vail CO 81657. 970-479-5783
The study was funded by Össur America. Dr. Richard Steadman is a consultant for Össur America.

Source Healio Orthopedics Today

An Update on Unloading Knee Braces in the Treatment of Unicompartmental Knee Osteoarthritis from the Last 10 Years: A Literature Review, Mistry DA, Chandratreya A, Lee PYF. Surg J (NY). 2018 Jul 2;4(3):e110-e118. DOI: 10.1055/s-0038-1661382. eCollection 2018 Jul. Review.

Effect of unloading brace treatment on pain and function in patients with symptomatic knee osteoarthritis: the ROTOR randomized clinical trial, Thoumie, Philippe; Marty, Marc; Avouac, Bernard; Pallez, Adeline; Vaumousse, Arnaud; Pipet, Linh Pham Thi; Monroche, André; Graveleau, Nicolas; Bonnin, Armand; Amor, Cyrine Ben; Coudeyre, Emmanuel. Scientific Reports volume 8, Article number: 10519 (2018). DOI:  10.1038/s41598-018-28782-3

The clinical effect of an unloader brace on patients with osteoarthritis of the knee, a randomized placebo controlled trial with one year follow up, Hjörtur F. Hjartarson and Sören Toksvig-Larsen. BMC Musculoskeletal Disorders 201819:341 DOI: 10.1186/s12891-018-2256-7

Is there a difference in outcome between two types of valgus unloading braces? A randomized controlled trial, Nienke van Egmond. Vol 83, No 4 (2017) Acta Orthopaedica Belgica

Unloading knee brace is a cost-effective method to bridge and delay surgery in unicompartmental knee arthritis, Paul YF Lee, Thomas G Winfield, Shaun RS Harris, Emerald Storey, Amit Chandratreya. BMJ Open Sport & Exercise Medicine 2017;2:e000195. DOI: 10.1136/bmjsem-2016-000195

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Does an unloader brace reduce knee loading in normally aligned knees? Ebert JR, Hambly K, Joss B, Ackland TR, Donnelly CJ. Clin Orthop Relat Res. 2014 Mar;472(3):915-22. DOI: 10.1007/s11999-013-3297-8. Epub 2013 Sep 25.

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