Recurrent ankle sprains
Following an acute injury, approximately 20-40% of patients will experience prolonged recurrent ankle weakness and sprains, especially when walking on uneven surfaces, and patients often feel a loss of control of the ankle joint and inversion. The sprain may or may not be accompanied by painful swelling. Some patients may feel stiffness in the ankle joint. At this point, the patient enters the chronic instability phase. The patient may have either mechanical instability or functional instability.
The former means that the patient has symptoms of instability while the ankle joint mobility exceeds the normal physiological range; the latter means that the ankle joint mobility does not exceed the normal physiological range, but for a long time after the injury, the ankle joint often becomes tender and is prone to repeated sprains when walking on uneven roads. In functional ankle instability, the patient’s subjective control over the ankle joint is reduced, but the ankle mobility does not exceed the normal physiological range.
In chronic lateral instability, that is, the instability may be mechanical or functional. Lateral ankle ligament rupture and laxity is the main cause of mechanical instability. Functional instability, on the other hand, is related to many factors. For example, damage to the receptor nerve fibers in the joint capsule and ligaments leads to proprioceptive impairment, resulting in decreased motor and reflex control and weakness of the ankle joint. Other factors such as peroneal muscle weakness and instability of the subtalar joint are also common causes.
1.Non-surgical treatment
The treatment of functional instability mainly consists of rehabilitation exercises such as peroneal muscle strength training, Achilles tendon pulling, ankle balance board and balance plate exercises. The duration of training should be no less than 10 weeks. In addition, external fixation with bandages and braces can reduce ankle hypermobility and increase the sense of ankle stability. However, Rarick reported that the use of adhesive tape fixation reduced the strength by 50% after 10 minutes of activity, and Freman reported that after functional rehabilitation training, 70-85% of functional instability could be achieved with good results.
2.Surgical treatment
For patients with mechanical instability, functional rehabilitation training should be carried out first, and if non-surgery fails, surgical treatment can be considered.
Surgical methods can be divided into two categories.
(1) Anatomical repair method. 1966 Dr. Lennart Brostrom first reported the anatomical repair method. In 1980, Nathaniel Gould modified Brostrom’s surgical approach by suturing the lateral portion of the extensor support band to the distal fibula in a dorsal lift to further strengthen the ligament repair. This procedure was later often referred to as the modified Brostrom-Gould procedure.
The advantage of anatomic repair of the lateral ligament is that it does not sacrifice its own tissues, and because there is no tendon fixation effect, there is little impact on the biomechanics of the ankle and subtalar joint and no stiffness of the subtalar joint occurs. Therefore, whether the injury is acute or chronic instability, anatomic repair methods can be used first, and when direct repair is difficult, non-anatomic reconstruction methods are used.
Modified Brostrom-Gould postoperative rehabilitation program
Phase 1 (1 week postoperatively)
1.Calf cast brace to fix the ankle joint in neutral position
2.Cold compress for 3 days
3. Pain relief
Phase 2 (2-6 weeks after surgery)
1.Replace the plaster brace or fix it with splint.
2.Prohibit ankle joint inversion and inversion
3.Start gentle ankle extension and flexion activities after 3 weeks
4.Start gentle peroneal tendon strength exercises after 3 weeks
Phase 3 (6 weeks after surgery)
1.Start balance exercises
2.Peroneal muscle strength exercises
3.Joint mobility exercises
Phase 4 (8-12 weeks)
Gradually resume various activities and sports
(2) Non-anatomical reconstruction methods. According to the literature, there are more than 50 kinds of surgical procedures and their modifications. They are further divided into 3 categories according to the different reconstruction materials used.
1.Use of peroneal tendon.
2) Use of metatarsal tendon, partial Achilles tendon or autologous free material graft.
3.The use of alternative materials such as carbon fiber, bovine collagen, etc.
The most commonly used reconstructive material is still the peroneal tendon, and the commonly used procedure is the Chrisman-Snook procedure: 1/2 of the short peroneal tendon is cut from the proximal end, first through the foramen of the talar neck bone, then through the foramen of the distal fibula, down through the foramen of the lateral wall of the heel bone, and finally sutured to the short peroneal tendon.
If the tendon is too short, it can be fixed directly to the lateral aspect of the heel. This procedure uses only half of the short peroneal tendon to reduce the effect on ankle valgus forces. The reconstructed tendon follows the anatomical direction of the original ligament, i.e. the anterior talofibular ligament is reconstructed and the heel-fibular ligament is reconstructed, which is an ideal non-anatomical reconstruction method.