Journal of Orthopaedic Surgery 2015;23(1):62-5
Ankle lateral ligament reconstruction for chronic instability Ren Yong,1 Kah Weng Lai,2 Lai Hock Ooi3
Department of Orthopaedic Surgery, Khoo Teck Puat Hospital, Singapore Department of Orthopaedic Surgery, National University Hospital, Singapore 3 Island Orthopaedic Consultants Pte Ltd, Mount Elizabeth Medical Centre, Singapore 1 2
ABSTRACT Purpose. To report the outcome of a technique combining direct anatomic reconstruction of the anterior talofibular ligament (ATFL) with augmented reconstruction using the peroneus brevis tendon fixed by a bio-absorbable interference screw. Methods. 13 men and 2 women aged 17 to 36 (mean, 24) years with recurrent inversion injuries of the right (n=5) and left (n=10) ankles underwent lateral ankle reconstruction by a single surgeon. All patients had a positive anterior drawer test and heel eversion stress test, and some degree of tenderness to palpation over the anterolateral joint capsule. All patients had complete or partial tear of the ATFL and the calcaneofibular ligament, except for one. The torn ligaments were repaired anatomically and reinforced with a split peroneus brevis tendon rerouted through the fibula and fixed with a bioabsorbable interference screw. The outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and the Foot and Ankle Outcome
Score (FAOS) at 6 months. Results. The mean time from injury to surgery was 40.5 months. The mean follow-up duration was 13.6 (range, 6–26) months. No patient had surgical or wound complications. The mean AOFAS ankle and hindfoot score was 91.5 (median, 93; range, 79–100). The mean FAOS was 78.8 (median, 77; range, 61– 100). 10 patients had no limitation in both daily and recreational activities; 3 had limitation in recreational activities, and 2 had limitation in both. 12 patients had normal and 3 had moderate limitation in hindfoot motion. One patient had hindfoot instability. Conclusion. The combination of augmented and direct anatomic reconstructions enables early mobilisation despite limitation in hindfoot motion and is a viable option for chronic hindfoot instability. Key words: ankle injuries; lateral ligament, ankle
INTRODUCTION The incidence of lateral ankle ligament injury is 7 per 1000 persons per year.1 Approximately 35% of
Address correspondence and reprint requests to: Ren Yong, Department of Orthopaedic Surgery, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828. Email: [email protected]
Vol. 23 No. 1, April 2015
such patients experience instability and up to 44% of patients with ruptured lateral ligaments have instability one year after non-operative treatment.2 30 to 40% of patients develop persistent instability necessitating reconstruction of the lateral ankle ligaments.3,4 The optimal treatment for chronic lateral ankle instability is controversial. Both direct anatomic and augmented reconstruction methods have been described.5–15 Direct anatomic reconstruction restores anatomy, preserves joint mechanics and subtalar motion, keeps gait unchanged, and results in minimal donorsite morbidity.5,6 End-to-end repair of the ruptured ligaments is feasible up to several years after the initial injury, but healing with scar tissue or lengthening results in insufficiency.7 The Chrisman-Snook procedure is an augmented reconstruction.8–15 The peroneus brevis tendon is usually used because it is expendable.16 The change in inversion-eversion subtalar motion after reconstruction is not significant.17–20 The modified Broström technique is the gold standard for patients with generalised ligamentous laxity or long-term instability, and for revision of failed Broström reconstructions.21 This study reports the outcome of a technique combining direct anatomic reconstruction of the anterior talofibular ligament (ATFL) with augmented reconstruction using the peroneus brevis tendon fixed by a bio-absorbable interference screw. MATERIALS AND METHODS Between September 2006 and May 2008, 13 male and 2 female consecutive patients aged 17 to 36 (mean, 24) years with recurrent inversion injuries of the right (n=5) and left (n=10) ankles after sporting injury (n=14) or fall from a height (n=1) despite intensive rehabilitation and use of ankle braces underwent lateral ankle reconstruction by a single surgeon. All patients had a positive anterior drawer test and heel eversion stress test, and some degree of tenderness to palpation over the anterolateral joint capsule. No patient had sensory changes or muscle weakness, nor diabetes or signs of generalised joint laxity. All patients had complete or partial tear of the ATFL and the calcaneofibular ligament (CFL), except for one; none had any chondral injury. Patients were placed in a lateral decubitus position under general anaesthesia with tourniquet control. A 10-cm curvilinear incision was started at the posterior border of the fibula and extended to the inferior tip of the lateral malleolus (Fig. a). Care
Ankle lateral ligament reconstruction for chronic instability
63
was taken to preserve the lateral cutaneous branch of the superficial peroneal nerve and sural nerve. The inferior extensor retinaculum and joint capsule were incised to expose the torn or attenuated ATFL. The peroneal tendons were retracted posteriorly to expose the torn or attenuated CFL. The proximal peroneal sheath was opened and the peroneus brevis was identified. The anterior half of the tendon was dissected and split distally to create a distally based graft 5 to 7 cm in length (Fig. b). A whipstitch was placed into the proximal end of the graft to facilitate passage through the osseous tunnel. The graft was passed inferiorly, avoiding the peroneal retinaculum at the inferior aspect of the wound. The bone at the area of contact between the scarred tissue and the lateral malleolus was decorticated using a rongeur. The ends of the ATFL and the capsule were plicated using interrupted 1/0 Vicryl 2 stitches (Ethicon, Johnson & Johnson, Somerville [NJ], USA). Any hypertrophic and embedded osseous bodies and excess fibrous tissue were excised. Hypertrophic fibrous tissue or synovium that could cause impingement was also excised. A 4.5-mm diameter, 5-cm-long osseous tunnel was drilled from the distal tip of the fibula proximally such that it exited along the posterior cortex of the fibula. A wire was used to facilitate the passage of the graft through the osseous tunnel. A 5.5x15-mm biotenodesis screw (Arthrex, Naples [FL], USA) was inserted into the tunnel to fix the graft in tension, with the foot held in eversion and the ankle at neutral dorsi- and plantar-flexion (Fig. c). The stability and range of motion of the ankle and the strength of the reconstructed ligament were checked using the inversion stress and anterior drawer tests to ensure normal subtalar and ankle motion. The tourniquet was deflated, haemostasis was obtained, and the wound was irrigated and closed. Postoperatively, the ankle was immobilised in the neutral position in a cast for one week. Full weight bearing with a long walking boot (Aircast, Summit [NJ], USA) was allowed at week 2. After 6 weeks, ankle and subtalar joint exercises and progressive strengthening and proprioceptive training were started. After 3 months, return to sports was allowed with use of ankle braces for at least a further 6 months. Outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and the Foot and Ankle Outcome Score (FAOS) at 6 months. The maximum AOFAS ankle and hindfoot score is 100 and includes pain (40), function (10), maximum walking distance (10), gait (8), sagittal and hindfoot motion (14), and stability and alignment (18).22 The FAOS is a questionnaire
64
Journal of Orthopaedic Surgery
R Yong et al.
(a)
Superficial peroneal nerve Anterior talofibular ligament
Sural nerve
Posterior talofibular ligament
Calcaneofibular ligament
Inferior extensor retinacuium Lateral talocalcaneal ligament
(b)
(c)
Figure Ankle lateral ligament reconstruction: (a) skin incision and the ligamentous structures, (b) harvesting and splitting the peroneus tendon graft, and (c) fixing the graft with a biotenodesis screw.
covering pain, symptoms, activities of daily living, sports/recreation, and quality of life.23 RESULTS The mean time from injury to surgery was 40.5 months. The mean follow-up duration was 13.6 (range, 6–26) months. No patient had surgical or wound complications. The mean AOFAS ankle and hindfoot score at 6 months was 91.5 (median, 93; range, 79–100). 10 patients had no pain and 5 had mild pain. 10 patients had no limitation in both daily and recreational activities; 3 had limitation in recreational activities, and 2 had limitation in both. Four patients reported no difficulty walking on uneven surfaces, whereas 10 reported some difficulty and one reported severe difficulty. All patients had normal gait. All but 2 patients had moderate limitation in sagittal
motion. 12 patients had normal and 3 had moderate limitation in hindfoot motion. One patient had hindfoot instability; all patients had good alignment of the hindfoot. The mean FAOS at 6 months was 78.8 (median, 77; range, 61–100); the mean±standard deviation sub-scores for pain, symptoms, activities of daily living, sport/recreation, and quality of life were 80.7±12.9, 82.4±14.0, 90.4±10.9, 74.3±15.7, 66.4±14.8, respectively. DISCUSSION Combining direct anatomic reconstruction of the ATFL with augmented reconstruction using the peroneus brevis anchored by a bio-absorbable interference screw enabled patients to return to weight-bearing with walking orthotics within a week of surgery, with only 3 patients having some limitation of hindfoot
Vol. 23 No. 1, April 2015
motion. The peroneus brevis tendon graft can be used in patients with generalised ligamentous laxity, in whom the modified Broström procedure may be insufficient.21 Bioabsorbable screws have been used in anterior cruciate reconstruction with great success. The bioabsorbable screw enabled direct tendon-tobone healing and maintenance of graft tension during fixation of the tendon within its transosseous tunnel. Stable fixation was achieved without any hardware
Ankle lateral ligament reconstruction for chronic instability
65
prominence. A 5.5-mm screw is recommended for the relatively small fibulas in the Asian population; larger screws may fracture the fibula. Although sural nerve entrapment and subsequent neuroma formation and neuropathic symptoms are reported complications,24 none of our patients had nerve complications, as care was taken to protect the lateral cutaneous branch of the superficial peroneal nerve and the sural nerve.
REFERENCES 1. Holmer P, Sondergaard L, Konradsen L, Nielson PT, Jorgensen LN. Epidemiology of sprains in the lateral ankle and foot. Foot Ankle Int 1994;15:72–4. 2. Freeman MA. Instability of the foot after injuries to the lateral ligament of the ankle. J Bone Joint Surg Br 1965;47:669–77. 3. Gerber JP, Williams GN, Scoville CR, Arciero RA, Taylor DC. Persistent disability associated with ankle sprains: a prospective examination of an athletic population. Foot Ankle Int 1998;19:653–60. 4. Verhagen RA, de Keizer G, van Dijk CN. Long-term follow-up of inversion trauma of the ankle. Arch Orthop Trauma Surg 1995;114:92–6. 5. Broström L. Sprained ankles. VI. Surgical treatment of “chronic” ligament ruptures. Acta Chir Scand 1966;132:551–65. 6. Gould N, Seligson D, Gassman J. Early and late repair of lateral ligament of the ankle. Foot Ankle 1980;1:84–9. 7. Ahlgren O, Larsson S. Reconstruction for lateral ligament injuries of the ankle. J Bone Joint Surg Br 1989;71:300–3. 8. Colville MR. Surgical treatment of the unstable ankle. J Am Acad Orthop Surg 1998;6:368–77. 9. Karlsson J, Bergsten T, Lansinger O, Peterson L. Reconstruction of the lateral ligaments of the ankle for chronic lateral instability. J Bone Joint Surg Am 1988;70:581–8. 10. Evans DL. Recurrent instability of the ankle; a method of surgical treatment. Proc R Soc Med 1953;46:343–4. 11. Ng ZD, Das De S. Modified Brostrom-Evans-Gould technique for recurrent lateral ankle ligament instability. J Orthop Surg (Hong Kong) 2007;15:306–10. 12. Snook GA, Chrisman OD, Wilson TC. Long-term results of the Chrisman-Snook operation for reconstruction of the lateral ligaments of the ankle. J Bone Joint Surg Am 1985;67:1–7. 13. Colville MR, Grondel RJ. Anatomic reconstruction of the lateral ankle ligaments using a split peroneus brevis tendon graft. Am J Sports Med 1995;23:210–3. 14. Anderson ME. Reconstruction of the lateral ligaments of the ankle using the plantaris tendon. J Bone Joint Surg Am 1985;67:930–4. 15. Sjolin SU, Dons-Jensen H, Simonsen O. Reinforced anatomical reconstruction of the anterior talofibular ligament in chronic anterolateral instability using a periosteal flap. Foot Ankle 1991;12:15–8. 16. St Pierre RK, Andrews L, Allman F Jr, Fleming LL. The Cybex II evaluation of lateral ankle ligamentous reconstructions. Am J Sports Med 1984;12:52–6. 17. Hollis JM, Blasier RD, Flahiff CM, Hofmann OE. Biomechanical comparison of reconstruction techniques in simulated lateral ankle ligament injury. Am J Sports Med 1995;23:678–82. 18. Cheng M, Tho KS. Chrisman-Snook ankle ligament reconstruction outcomes—a local experience. Singapore Med J 2002;43:605–9. 19. Ahlgren O, Larsson S. Reconstruction for lateral ligament injuries of the ankle. J Bone Joint Surg Br 1989;71:300–3. 20. Leach RE, Namiki O, Paul GR, Stockel J. Secondary reconstruction of the lateral ligaments of the ankle. Clin Orthop Relat Res 1981;160:201–11. 21. Baumhauer JF, O’Brien T. Surgical considerations in the treatment of ankle instability. J Athl Train 2002;37:458–62. 22. Halasi T, Kynsburg A, Tallay A, Berkes I. Development of a new activity score for the evaluation of ankle instability. Am J Sports Med 2004;32:899–908. 23. Roos RM, Brandsson S, Karlsson J. Validation of the foot and ankle outcome score for ankle ligament reconstruction. Foot Ankle Int 2001;22:788–94. 24. Yang J Jr, Morscher MA, Weiner DS. Modified Chrisman-Snook repair for the treatment of chronic ankle ligamentous instability in children and adolescents. J Child Orthop 2010;4:561–70.
Ankle lateral ligament reconstruction for chronic instability Ren Yong,1 Kah Weng Lai,2 Lai Hock Ooi3
Department of Orthopaedic Surgery, Khoo Teck Puat Hospital, Singapore Department of Orthopaedic Surgery, National University Hospital, Singapore 3 Island Orthopaedic Consultants Pte Ltd, Mount Elizabeth Medical Centre, Singapore 1 2
ABSTRACT Purpose. To report the outcome of a technique combining direct anatomic reconstruction of the anterior talofibular ligament (ATFL) with augmented reconstruction using the peroneus brevis tendon fixed by a bio-absorbable interference screw. Methods. 13 men and 2 women aged 17 to 36 (mean, 24) years with recurrent inversion injuries of the right (n=5) and left (n=10) ankles underwent lateral ankle reconstruction by a single surgeon. All patients had a positive anterior drawer test and heel eversion stress test, and some degree of tenderness to palpation over the anterolateral joint capsule. All patients had complete or partial tear of the ATFL and the calcaneofibular ligament, except for one. The torn ligaments were repaired anatomically and reinforced with a split peroneus brevis tendon rerouted through the fibula and fixed with a bioabsorbable interference screw. The outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and the Foot and Ankle Outcome
Score (FAOS) at 6 months. Results. The mean time from injury to surgery was 40.5 months. The mean follow-up duration was 13.6 (range, 6–26) months. No patient had surgical or wound complications. The mean AOFAS ankle and hindfoot score was 91.5 (median, 93; range, 79–100). The mean FAOS was 78.8 (median, 77; range, 61– 100). 10 patients had no limitation in both daily and recreational activities; 3 had limitation in recreational activities, and 2 had limitation in both. 12 patients had normal and 3 had moderate limitation in hindfoot motion. One patient had hindfoot instability. Conclusion. The combination of augmented and direct anatomic reconstructions enables early mobilisation despite limitation in hindfoot motion and is a viable option for chronic hindfoot instability. Key words: ankle injuries; lateral ligament, ankle
INTRODUCTION The incidence of lateral ankle ligament injury is 7 per 1000 persons per year.1 Approximately 35% of
Address correspondence and reprint requests to: Ren Yong, Department of Orthopaedic Surgery, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore 768828. Email: [email protected]
Vol. 23 No. 1, April 2015
such patients experience instability and up to 44% of patients with ruptured lateral ligaments have instability one year after non-operative treatment.2 30 to 40% of patients develop persistent instability necessitating reconstruction of the lateral ankle ligaments.3,4 The optimal treatment for chronic lateral ankle instability is controversial. Both direct anatomic and augmented reconstruction methods have been described.5–15 Direct anatomic reconstruction restores anatomy, preserves joint mechanics and subtalar motion, keeps gait unchanged, and results in minimal donorsite morbidity.5,6 End-to-end repair of the ruptured ligaments is feasible up to several years after the initial injury, but healing with scar tissue or lengthening results in insufficiency.7 The Chrisman-Snook procedure is an augmented reconstruction.8–15 The peroneus brevis tendon is usually used because it is expendable.16 The change in inversion-eversion subtalar motion after reconstruction is not significant.17–20 The modified Broström technique is the gold standard for patients with generalised ligamentous laxity or long-term instability, and for revision of failed Broström reconstructions.21 This study reports the outcome of a technique combining direct anatomic reconstruction of the anterior talofibular ligament (ATFL) with augmented reconstruction using the peroneus brevis tendon fixed by a bio-absorbable interference screw. MATERIALS AND METHODS Between September 2006 and May 2008, 13 male and 2 female consecutive patients aged 17 to 36 (mean, 24) years with recurrent inversion injuries of the right (n=5) and left (n=10) ankles after sporting injury (n=14) or fall from a height (n=1) despite intensive rehabilitation and use of ankle braces underwent lateral ankle reconstruction by a single surgeon. All patients had a positive anterior drawer test and heel eversion stress test, and some degree of tenderness to palpation over the anterolateral joint capsule. No patient had sensory changes or muscle weakness, nor diabetes or signs of generalised joint laxity. All patients had complete or partial tear of the ATFL and the calcaneofibular ligament (CFL), except for one; none had any chondral injury. Patients were placed in a lateral decubitus position under general anaesthesia with tourniquet control. A 10-cm curvilinear incision was started at the posterior border of the fibula and extended to the inferior tip of the lateral malleolus (Fig. a). Care
Ankle lateral ligament reconstruction for chronic instability
63
was taken to preserve the lateral cutaneous branch of the superficial peroneal nerve and sural nerve. The inferior extensor retinaculum and joint capsule were incised to expose the torn or attenuated ATFL. The peroneal tendons were retracted posteriorly to expose the torn or attenuated CFL. The proximal peroneal sheath was opened and the peroneus brevis was identified. The anterior half of the tendon was dissected and split distally to create a distally based graft 5 to 7 cm in length (Fig. b). A whipstitch was placed into the proximal end of the graft to facilitate passage through the osseous tunnel. The graft was passed inferiorly, avoiding the peroneal retinaculum at the inferior aspect of the wound. The bone at the area of contact between the scarred tissue and the lateral malleolus was decorticated using a rongeur. The ends of the ATFL and the capsule were plicated using interrupted 1/0 Vicryl 2 stitches (Ethicon, Johnson & Johnson, Somerville [NJ], USA). Any hypertrophic and embedded osseous bodies and excess fibrous tissue were excised. Hypertrophic fibrous tissue or synovium that could cause impingement was also excised. A 4.5-mm diameter, 5-cm-long osseous tunnel was drilled from the distal tip of the fibula proximally such that it exited along the posterior cortex of the fibula. A wire was used to facilitate the passage of the graft through the osseous tunnel. A 5.5x15-mm biotenodesis screw (Arthrex, Naples [FL], USA) was inserted into the tunnel to fix the graft in tension, with the foot held in eversion and the ankle at neutral dorsi- and plantar-flexion (Fig. c). The stability and range of motion of the ankle and the strength of the reconstructed ligament were checked using the inversion stress and anterior drawer tests to ensure normal subtalar and ankle motion. The tourniquet was deflated, haemostasis was obtained, and the wound was irrigated and closed. Postoperatively, the ankle was immobilised in the neutral position in a cast for one week. Full weight bearing with a long walking boot (Aircast, Summit [NJ], USA) was allowed at week 2. After 6 weeks, ankle and subtalar joint exercises and progressive strengthening and proprioceptive training were started. After 3 months, return to sports was allowed with use of ankle braces for at least a further 6 months. Outcome was assessed using the American Orthopaedic Foot and Ankle Society (AOFAS) ankle and hindfoot score and the Foot and Ankle Outcome Score (FAOS) at 6 months. The maximum AOFAS ankle and hindfoot score is 100 and includes pain (40), function (10), maximum walking distance (10), gait (8), sagittal and hindfoot motion (14), and stability and alignment (18).22 The FAOS is a questionnaire
64
Journal of Orthopaedic Surgery
R Yong et al.
(a)
Superficial peroneal nerve Anterior talofibular ligament
Sural nerve
Posterior talofibular ligament
Calcaneofibular ligament
Inferior extensor retinacuium Lateral talocalcaneal ligament
(b)
(c)
Figure Ankle lateral ligament reconstruction: (a) skin incision and the ligamentous structures, (b) harvesting and splitting the peroneus tendon graft, and (c) fixing the graft with a biotenodesis screw.
covering pain, symptoms, activities of daily living, sports/recreation, and quality of life.23 RESULTS The mean time from injury to surgery was 40.5 months. The mean follow-up duration was 13.6 (range, 6–26) months. No patient had surgical or wound complications. The mean AOFAS ankle and hindfoot score at 6 months was 91.5 (median, 93; range, 79–100). 10 patients had no pain and 5 had mild pain. 10 patients had no limitation in both daily and recreational activities; 3 had limitation in recreational activities, and 2 had limitation in both. Four patients reported no difficulty walking on uneven surfaces, whereas 10 reported some difficulty and one reported severe difficulty. All patients had normal gait. All but 2 patients had moderate limitation in sagittal
motion. 12 patients had normal and 3 had moderate limitation in hindfoot motion. One patient had hindfoot instability; all patients had good alignment of the hindfoot. The mean FAOS at 6 months was 78.8 (median, 77; range, 61–100); the mean±standard deviation sub-scores for pain, symptoms, activities of daily living, sport/recreation, and quality of life were 80.7±12.9, 82.4±14.0, 90.4±10.9, 74.3±15.7, 66.4±14.8, respectively. DISCUSSION Combining direct anatomic reconstruction of the ATFL with augmented reconstruction using the peroneus brevis anchored by a bio-absorbable interference screw enabled patients to return to weight-bearing with walking orthotics within a week of surgery, with only 3 patients having some limitation of hindfoot
Vol. 23 No. 1, April 2015
motion. The peroneus brevis tendon graft can be used in patients with generalised ligamentous laxity, in whom the modified Broström procedure may be insufficient.21 Bioabsorbable screws have been used in anterior cruciate reconstruction with great success. The bioabsorbable screw enabled direct tendon-tobone healing and maintenance of graft tension during fixation of the tendon within its transosseous tunnel. Stable fixation was achieved without any hardware
Ankle lateral ligament reconstruction for chronic instability
65
prominence. A 5.5-mm screw is recommended for the relatively small fibulas in the Asian population; larger screws may fracture the fibula. Although sural nerve entrapment and subsequent neuroma formation and neuropathic symptoms are reported complications,24 none of our patients had nerve complications, as care was taken to protect the lateral cutaneous branch of the superficial peroneal nerve and the sural nerve.
REFERENCES 1. Holmer P, Sondergaard L, Konradsen L, Nielson PT, Jorgensen LN. Epidemiology of sprains in the lateral ankle and foot. Foot Ankle Int 1994;15:72–4. 2. Freeman MA. Instability of the foot after injuries to the lateral ligament of the ankle. J Bone Joint Surg Br 1965;47:669–77. 3. Gerber JP, Williams GN, Scoville CR, Arciero RA, Taylor DC. Persistent disability associated with ankle sprains: a prospective examination of an athletic population. Foot Ankle Int 1998;19:653–60. 4. Verhagen RA, de Keizer G, van Dijk CN. Long-term follow-up of inversion trauma of the ankle. Arch Orthop Trauma Surg 1995;114:92–6. 5. Broström L. Sprained ankles. VI. Surgical treatment of “chronic” ligament ruptures. Acta Chir Scand 1966;132:551–65. 6. Gould N, Seligson D, Gassman J. Early and late repair of lateral ligament of the ankle. Foot Ankle 1980;1:84–9. 7. Ahlgren O, Larsson S. Reconstruction for lateral ligament injuries of the ankle. J Bone Joint Surg Br 1989;71:300–3. 8. Colville MR. Surgical treatment of the unstable ankle. J Am Acad Orthop Surg 1998;6:368–77. 9. Karlsson J, Bergsten T, Lansinger O, Peterson L. Reconstruction of the lateral ligaments of the ankle for chronic lateral instability. J Bone Joint Surg Am 1988;70:581–8. 10. Evans DL. Recurrent instability of the ankle; a method of surgical treatment. Proc R Soc Med 1953;46:343–4. 11. Ng ZD, Das De S. Modified Brostrom-Evans-Gould technique for recurrent lateral ankle ligament instability. J Orthop Surg (Hong Kong) 2007;15:306–10. 12. Snook GA, Chrisman OD, Wilson TC. Long-term results of the Chrisman-Snook operation for reconstruction of the lateral ligaments of the ankle. J Bone Joint Surg Am 1985;67:1–7. 13. Colville MR, Grondel RJ. Anatomic reconstruction of the lateral ankle ligaments using a split peroneus brevis tendon graft. Am J Sports Med 1995;23:210–3. 14. Anderson ME. Reconstruction of the lateral ligaments of the ankle using the plantaris tendon. J Bone Joint Surg Am 1985;67:930–4. 15. Sjolin SU, Dons-Jensen H, Simonsen O. Reinforced anatomical reconstruction of the anterior talofibular ligament in chronic anterolateral instability using a periosteal flap. Foot Ankle 1991;12:15–8. 16. St Pierre RK, Andrews L, Allman F Jr, Fleming LL. The Cybex II evaluation of lateral ankle ligamentous reconstructions. Am J Sports Med 1984;12:52–6. 17. Hollis JM, Blasier RD, Flahiff CM, Hofmann OE. Biomechanical comparison of reconstruction techniques in simulated lateral ankle ligament injury. Am J Sports Med 1995;23:678–82. 18. Cheng M, Tho KS. Chrisman-Snook ankle ligament reconstruction outcomes—a local experience. Singapore Med J 2002;43:605–9. 19. Ahlgren O, Larsson S. Reconstruction for lateral ligament injuries of the ankle. J Bone Joint Surg Br 1989;71:300–3. 20. Leach RE, Namiki O, Paul GR, Stockel J. Secondary reconstruction of the lateral ligaments of the ankle. Clin Orthop Relat Res 1981;160:201–11. 21. Baumhauer JF, O’Brien T. Surgical considerations in the treatment of ankle instability. J Athl Train 2002;37:458–62. 22. Halasi T, Kynsburg A, Tallay A, Berkes I. Development of a new activity score for the evaluation of ankle instability. Am J Sports Med 2004;32:899–908. 23. Roos RM, Brandsson S, Karlsson J. Validation of the foot and ankle outcome score for ankle ligament reconstruction. Foot Ankle Int 2001;22:788–94. 24. Yang J Jr, Morscher MA, Weiner DS. Modified Chrisman-Snook repair for the treatment of chronic ankle ligamentous instability in children and adolescents. J Child Orthop 2010;4:561–70.
