Endoscopic Approach to Proximal Hamstring Avulsion Repair
Authors: Suppauksorn Sunikom , Nwachukwu Benedict U. , Beck Edward C. , Okoroha Kelechi R. , Nho Shane J. 
Published: December 2020

Background:
Endoscopic repair of a proximal hamstring avulsion promotes precise anatomical repair and lowers the risk of neurovascular injury.

Description:
Indications for proximal endoscopic repair of the proximal part of the hamstrings include acute tears of 2 tendons with >2 cm of retraction in young active patients, acute complete tears of 3 tendons with >2 cm of retraction, or failed conservative treatment of tears of ≥2 tendons with ≤2 cm of retraction. Repair of a proximal hamstring avulsion is performed using 2 portals. The medial portal is developed percutaneously under fluoroscopic guidance. The lateral portal is developed under direct visualization. The footprint of the hamstrings is identified from medial to lateral. The sciatic and posterior femoral cutaneous nerves must be carefully identified and protected. The avulsed tendons are fixed with suture anchors with the knee in flexion.

Alternatives:
Conservative treatment is commonly used to treat injuries of the musculotendinous junction (type 2), incomplete or complete avulsion with minimal retraction (≤2 cm) (type 3 or 4, respectively), and patients with limited mobility or severe comorbidities
1
. The initial treatments consist of RICE (rest, ice, compression, and elevation), protective ambulation, and then physical therapy. Open repair is used for incomplete or complete avulsion with >2 cm of retraction, or when conservative treatments have failed
1–3
. Open reconstruction is used for chronic avulsion with tendon retraction of >5 cm
4–6
.

Rationale:
Endoscopic surgery is a minimally invasive procedure that offers excellent visualization of the subgluteal space without gluteus maximus muscle retraction. In open repair, the inferior border of the gluteus maximus muscle is mobilized to access the ischial tuberosity. The mean distance (and standard deviation) from the inferior border of the gluteus maximus muscle to the hamstring origin has been reported to be 6.3 ± 1.3 cm, which is close to the mean distance from the inferior border of the gluteus maximus to the inferior gluteal nerve and artery, which has been reported to be 5.0 ± 0.8 cm
7
. Open repair, which requires gluteus maximus retraction, poses an injury risk to the inferior gluteal nerve and artery. Open repair increases the risk of wound infection because the incision involves the perineum
8
. The feasibility of the endoscopic repair depends on the chronicity and amount of tendon retraction. It is feasible for a symptomatic tear of ≥2 tendons with a retraction of ≤2 cm. Mobilization of the retracted tendon is challenging in endoscopic repair. In acute injuries, the degree of retraction is not critical because the tendon is easily mobilized. Chronic injuries (>2 months) and those with far tendon retraction (>5 cm) are not suitable for endoscopy
9
. In chronic injuries with incomplete or complete avulsion with minimal retraction (≤2 cm) (types 3 and 4) that have failed conservative treatment, endoscopy is suitable since the tendon is not retracted
1
. Endoscopic repair can be converted to an open procedure in difficult endoscopic conditions.