Lateral ligament instability

Lateral ligament injury of the ankle is very common (90) with 1 in 10,000 sustaining the injury per day it is the commonest ligament injury seen by surgeons.

Repeated lateral ligament injuries interfere with normal daily life (90, 91) and with chronic instability a minor trauma can cause a significant inversion injury with unpredictable outcome (90, 92).

Surgery to correct lateral ligament instability was described as early as 1949 by Nilsonne who described a peroneus brevis transfer (93). But it was Brostrom (94) who showed that direct repair of the lateral ligament was possible even years after acute injury and Hamilton (95) reported 93% good or excellent results with a modified Brostrom procedure.

With lateral ligament tears, it is the anterior talo-fibular ligament that fails first - calcaneo fibular ligament rupture is rare (94). A repair/reconstruction ideally needs to reproduce the ATFL in its anatomic position (96) and this is what a Brostrom or Hamilton procedure does.

The diagnosis of lateral ligament instability is straightforward - if there is a history of instability, the lateral ligaments are tender and moving the ankle demonstrates excessive inversion and an exaggerated anterior draw test. This is when the foot and talusare translocated anteriorly in the mortis and the amount of anterior movement recorded and compared with the normal side .

Radiographic lateral stress views can be performed applying set forces of inversion (90). But results of such instability testing can be questionable if the calcaneofibular ligament is intact and these patients still have instability (97, 98)

Arthroscopically, there is ballooning of the anterolateral capsule which appears and feels thinner than normal. One frequently sees scarring of the lateral gutter and syndesmosis with associated loose bodies or ossicles and lateral dome or plafond chondral changes.

Treatment is either an open or closed modified Brostrom repair with three weeks in a below-knee cast then standard physiotherapy. Arthroscopic results are as good as open (99).

Krips R (100) in 2006 produced an excellent article regarding ankle instability injuries and reconstruction. Takao M (101) in 2005 clearly demonstrated in their series of 72 patients that arthroscopy can be used to diagnose the cause of residual pain after and ankle sprain in most cases that are otherwise undiagnosable by clinical examination and imaging. Also Okuda R (102) in 2005 interestingly showed in their series of 30 consecutive patients that lateral ligament reconstruction can be successful regardless of focal chondral lesions as long as pre-op weight-bearing x-rays do not show any joint space narrowing.

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References
(90) Glasgow M, Jackson A, Jamieson A M, ‘Instability of the ankle after injury to the lateral ligament’ JBJS 1980; 62B:196
(91) Sefton G K, George J, Fitton J M, McMullen H, ‘Reconstruction of the anterior talofibular ligament for the treatment of the unstable ankle’ JBJS 1979; 61B:352 .
(92) Hawkins R B, ‘Arthroscopic repair for chronic lateral ankle instability’ In Guhl J F, ed ‘Foot and ankle arthroscopy’ Thorafore , N J: Slack, 1993: 155.
(93) Nilsonne H, ‘Making a new ligament in ankle sprain’ JBJS 1949 ; 31A : 380
(94) Brostrom L, ‘Sprained ankles : VI. Surgical treatment of ‘chronic’ ligament ruptures’ Acta Chir Scand 1966 ; 132 : 551
(95) Hamilton W G, Thomson F M, Snow S W, ‘The modified Brostrom procedure for lateral ankle instability’ Foot Ankle 1993; 14:1
(96) Colville M R, Marder R A, Zarins B ‘Reconstruction of the lateral ankle ligaments - a biomechanical analysis’ Am J Sports Med 1991 ; 20 :594.
(97) Johnson E E, Markolf K L, ‘The contribution of the anterior talofibular ligament to ankle joint laxity’ JBJS 1983; 65A:81 .
(98) Ruth C J, ‘The surgical treatment of the fibular collateral ligament of the ankle’ JBJS 1961; 43A:229
(99) Gollehon D L, Drez D, ‘Ankle arthroscopy - approaches and technique’ Orthopaedics 1983; 6:1150
(100) Krips R, de Vries J, van Dijk C N, ‘Ankle Instability’ Foot and Ankle Clinics 2006; 11:2; 311-29
(101) Takao M, UchioY, Naito K, Fukazawa I, Ochi M, ‘Arthroscopic assessment for intra-articular disorders in residual ankle disability after sprain’ Am J Sports Med 2005; 33:5; 686-92
(102) Okuda R, Kinoshite M, Morikawa J, Yasuda T, Abe M, ‘Arthroscopic ankle findings in chronic ankle instability: do focal chondral lesions influence the results of ligament reconstruction?’ Am J Sports Med 2005; 33:1; 35-42