SLR - November 2017 - Najwah S. Hayman

Endoscopic Versus Open Excision of Os Trigonum for the Treatment of Posterior Ankle Impingement Syndrome in an Athletic Population: A Randomized Controlled Study with Five-Year Follow-Up

Reference: Georgiannos D, Bisbinas I. Endoscopic Versus Open Excision of Os Trigonum for the Treatment of Posterior Ankle Impingement Syndrome in an Athletic Population: A Randomized Controlled Study with Five-Year Follow-Up. The American Journal of Sports Medicine. 2017 Jan 23; 45(6): 1388–1394.

Scientific Literature Review

Reviewed By: Najwah S. Hayman, DPM
Residency Program: Cambridge Health Alliance, Cambridge, MA

Podiatric Relevance: Posterior Ankle Impingement Syndrome (PAIS) is a clinical condition characterized by repeat forced plantarflexion of the ankle. It is predominantly seen among athletes, and is largely due to compression of the os trigonum between the tibia and calcaneus. Traditionally, this type of injury has been treated with open excision of the os trigonum. However, as there has been growing interest in minimally invasive surgery, the idea of using an endoscopic approach has become more popularized. This study systematically compares endoscopic to open excision of the os trigonum for treatment of PAIS in athletes, with the notion that endoscopic excision produces more favorable functional outcomes, decreased pain and a shorter recovery time.

Methods: A level II prospective, randomized, controlled trial was performed in a single institution for athletes with PAIS due to a symptomatic os trigonum. A total of 52 patients were enrolled for elective surgery between 2008 and 2011. All patients underwent conservative treatment for a minimum of six months prior to being placed in Group A, open excision surgery (n=26), or Group B, endoscopic excision (n=26). The primary outcomes measured were postoperative complications, time to return to training and time to return to previous sports level. Functional outcome was evaluated with the American Orthopedic Foot and Ankle Society (AOFAS) hindfoot score. Pain was recorded using the Visual Analog Score-Foot and Ankle (VAS-FA). Patients were followed for five years postoperatively to obtain the necessary data.   

Results: Group A had an overall postoperative complication rate of 23 percent compared to Group B at 3.8 percent and included cases of infection, sural nerve injury and complex regional pain syndrome (P < 0.001). The average time to return to training was 9.58 + 3.98 weeks for Group A and 4.58 + 1.47 weeks for Group B (P < 0.001). Mean time to return to previous sports level was 11.54 + 3.89 weeks for Group A and 7.12 + 2.25 weeks for Group B. Patients treated with endoscopic excision showed significant improvement in AOFAS scores compared to those treated with open approach (P < 0.05). No statistical significance resulted for postoperative VAS-FA pain scores between both groups.

Conclusions: The authors conclude that with regards to function and pain, both open and endoscopic approaches produce reasonably good outcomes. However, endoscopic excision resulted in fewer postoperative complications and shorter recovery time—two important factors for an athletic patient population. Although not addressed in this study, other factors to consider when deciding between open and endoscopic excision include the cost of both procedures and the skill level of the surgeon (more training may be required for endoscopic technique). Nevertheless, endoscopic excision for the treatment of PAIS due to symptomatic os trigonum appears to be a safe and effective procedure and is a great alternative to the gold standard open excision approach. This study may be limited by a small sample size, but it provides some evidence to support the advantages of endoscopic minimally invasive surgery compared to traditional open methods. 

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