(Reuters Health) - Patients with arthritic knees can add hip-strengthening exercises to their workout to improve the ability to walk and maybe reduce pain, according to a research review.

Based on pooled data from eight clinical trials with a total of 340 patients, the study team concludes in the British Journal of Sports Medicine that hip strengthening exercises involving weights or elastic bands would help the most.

“Despite knowing that exercise is beneficial, what type of exercise should be included in a thorough exercise program remains largely unknown,” said lead author Andrew Hislop of the University of Queensland in Brisbane, Australia.

Most international guidelines recommend exercise in the conservative management of knee osteoarthritis, a bone and cartilage disease that affects one in four people over age 55. However, many doctors don’t follow up on this advice with patients or refer them to the proper physiotherapist for an additional appointment, Hislop noted.

“With a growing population and increasing number of lower limb injuries, there is going to be an ever increasing burden on the health system to manage knee osteoarthritis,” he told Reuters Health by email.

Hislop and colleagues conducted a systematic review and meta-analysis of randomized controlled trials that investigated the effect of adding hip-strengthening exercises to a regimen often prescribed to strengthen the quadriceps muscles at the front of the thigh for people with knee arthritis.

The researchers looked at whether aspects of knee and walking function improved, as well as whether pain and quality of life were affected by the added hip-strengthening routine.

They also evaluated three types of hip exercises to see which had the greatest effect: resistance weight-lifting, functional neuromuscular exercises such as single-leg squats or stepping, and so-called multimodal exercise that combined these two.

Overall, adding hip-strengthening significantly improved walking function, though it did not have a statistically meaningful effect on pain, stair function or the ability to stand from a sitting position.

When researchers looked at individual types of hip exercise, however, they found that resistance exercises in particular were more effective than functional neuromuscular exercises for improving pain and functioning. Multimodal exercise had no added effect.

“Strengthening the hip muscles, particularly the hip abductors, might improve pelvic drop and trunk control, lightening the load on the knee,” Hislop said.

“Many health professionals are concerned only with the site affected by the disease, forgetting the regional consequences of the disease” at the hip or beyond, said Dr. Jamil Natour, chief of rheumatology at the Federal University of Sao Paulo in Brazil, who wasn’t involved in the study.

“We should verify that the ‘normal’ hip of a patient with knee osteoarthritis is evaluated and possibly rehabilitated,” he told Reuters Health by email.

Researchers also want to understand exactly how exercise influences knee osteoarthritis pain. The effect be physical, but could also stem from other factors such as a general improvement in wellbeing, attention from a healthcare professional or a placebo effect.

“Over the last decade or so, many researchers have looked for the optimal exercise program, but unfortunately, without luck,” said Marius Henriksen, head of the Physiotherapy and Biomechanics Research unit at Copenhagen University Hospital in Frederiksberg, Denmark, who wasn’t involved with the study.

“To me, that suggests that the exercise that is effective is the exercise that is being done,” he told Reuters Health by email. “Go out there and exercise and be physically active, and do something that you find fun and meaningful.”

SOURCE: bit.ly/2CjwUpx British Journal of Sports Medicine, online February 6, 2019.