Ankle Injuries - Peroneus Longus Tendinopathy
‘Susan’ is a 65 year-old moderately overweight lady who came to see me in late August 2015. She had a 3 month history of right posterior and lateral ankle to mid-foot pain. Initially, the pain was intermittent, but over time it became constant and more severe. It was aggravated by any walking, particularly up hills. She developed a very antalgic gait, which she said had been present for over a month.
Her GP sent her for an MRI in early July which reported peroneus longus tenosynovitis. The radiologist recommended an US-guided cortisone injection into the sheath, and this was performed in mid-July. This gave her some relief for two weeks, then the pain returned worse than ever.
On her initial examination she walked with all her weight on her instep, and with the right leg externally rotated. She had a cavus / supinated foot type. Walking produced pain rated as 7 out of 10. Interestingly, she could weight-bear on her toes without any exacerbation of pain.
On palpation she was very tender over the peroneus longus tendon at the point where it turned medially under the cuboid. She was fearful that this condition would be permanent, and her main goal at that point was to be able to walk without pain. Her ultimate goal was to one day return to tennis.
On the initial treatment I released trigger-points within the belly of the muscle, and gave her non-weight bearing isometric resisted plantarflexion and eversion exercises. These were sustained for 45 seconds, repeated 5 times, in sets of 4. I strapped her ankle to take some load off the tendon and to pronate the midfoot, and I supplied her with heel raises. She was given strict instructions to avoid walking in flat shoes or bare feet, and to avoid walking up hills. When walking down stairs she was instructed to lead with the right leg and to go one step at a time.
Immediately after the first session of isometric exercises, Susan reported that her pain reduced to 2 out of 10, and she was able to walk with minimal limp for the first time in over a month. I reviewed her a week later and she had strictly followed my instructions and performed her exercises 3-4 times daily. She reported being 80% better. She walked almost normally and with only 1 out of 10 pain. On this occasion I progressed her to full-weight-bearing isometric exercises. I saw her on 5 further occasions over the next 4 months, progressing her to more functional exercises including lateral stepping up-on-toes, balance drills, resisted through range plantar-flexion / eversion, and even light jogging and hitting a ball against a wall. She returned to social tennis in late November, with no aggravation of her pain. At her last visit in December she reported having had no pain for the past 2 months. I put her through some vigorous testing including lateral jumping, pivoting and propping, and she performed all this without any problem. I cleared her to return to all normal activities, including tennis, in the New Year.
Peroneus longus tendinopathy is very uncommon. It is seen mostly in people who over-supinate, and sometimes as a traction injury after ankle sprain. As with most tendon disease, this condition is exacerbated by compression between the tendon and underlying bone – in this case the cuboid. Initial management involves unloading the tendon, and avoiding compression so the healing process can commence. In acute and medium-term tendinopathies, isometric exercises have been shown to be beneficial in promoting healing, and often in providing effective pain-relief. The use of cortisone is controversial. If the tendon sheath or an involved bursa is inflamed, cortisone is often reported to be effective. However the tendon itself does not respond well, and there is very good evidence that cortisone injections around and within tendons leads to worse medium and long-term outcomes. This has been found for the extensor tendons of the forearm (tennis elbow) and Achilles tendon.
Very good research over the past 15 years has shown that the cornerstone of effective tendon management is an appropriate exercise programme. No other therapy has shown consistently reliable results. A good understanding of the mechanics underlying each tendon problem is essential, so that overload &/or compressive forces can be effectively reduced. The most appropriate form of exercise will depend on the stage and type of tendon disease.