Authors: Aaron Leininger, Robert A. Duerr, Aakash Chauhan, Ryan P. McGovern, John J. Christoforetti
Categories: Technical Note
Source: Arthroscopy Techniques
Hamstring injuries commonly occur at the musculotendinous junction; however, they can occur as proximal avulsion injuries. A lack of recognition can lead to proximal hamstring injuries being frequently misdiagnosed, resulting in delayed treatment. Chronic proximal hamstring tears are often retracted and scarred to the surrounding soft tissues. Owing to the poor quality of tissue at the torn ends of the tendon, an augmented reconstruction using an allograft may be required. In cases with poor visualization of the ischial tuberosity and proximal hamstring footprint, an Achilles tendon allograft can be secured directly to the tuberosity with suture anchors. However, visualization of the footprint can be optimized using an arthroscope. This report describes a technique for endoscopic-assisted anatomic reconstruction using an Achilles allograft with both knotless and knotted suture anchors for chronic complete avulsions of the proximal hamstring.
Complete rupture of the proximal hamstring accounts for approximately 9% of all hamstring injuries.^1^ Although hamstring muscle strains are among the most common injuries in athletes and respond well to conservative management, complete ruptures generally have poor outcomes with conservative treatment.1, 2, 3 There is a lack of consensus regarding timing and indications for surgery,^1^ with several reported indications including avulsion of 2 tendons with more than 2 cm of retraction, complete avulsion of all 3 tendons, displaced bony avulsions, and partial avulsions with persistent pain despite extensive conservative treatment.^4^^,^^5^ It is also important to consider patient factors during surgical consultation, such as age, activity level, functional demands, and expectations. Delayed surgical intervention (>4 weeks) is associated with prolonged morbidity and can be associated with a higher rate of complications owing to the increased technical difficulty required to perform the surgical procedure. However, this is sometimes unavoidable in patients presenting late after injury.6, 7, 8
Chronic proximal hamstring avulsions are often retracted and scarred to surrounding soft tissues. This presentation is more typical of middle-aged patients with an isolated injury causing persistent pain, weakness, and sciatica-like symptoms due to nerve irritation. Preoperative magnetic resonance images showing a chronic proximal hamstring avulsion are presented in Figure 1. These patients are more likely to have poor-quality tissue at the torn ends of the tendon and may require an augmented reconstruction using an allograft. A technique for Achilles allograft reconstruction of chronic complete proximal hamstring ruptures has previously been described with favorable results.^9^^,^^10^ This technique requires an extensive incision, identification of the sciatic nerve and torn tendons, fixation of the distal end of the Achilles allograft to the tuberosity as a bone plug with an interference screw, and suturing of the proximal allograft to the hamstring tendons with a combination of absorbable and nonabsorbable sutures at the desired tension.^7^^,^^9^ In cases with poor visualization of the ischial tuberosity–proximal hamstring footprint, the allograft Achilles tendon is secured directly to the tuberosity with suture anchors as dictated by visualization of the footprint.^9^ Achieving an anatomic reattachment of the proximal hamstring tendons to the footprint can be technically demanding in these cases. In this report, we describe a technique for endoscopic-assisted anatomic reconstruction using Achilles allograft with both knotless and knotted suture anchors for chronic complete avulsions of the proximal hamstring.
After induction of general anesthesia, the patient is placed prone on the operating table with all bony prominences padded. In this case, an ultrasound examination was performed to identify the stump of the retracted proximal hamstring tendons and to mark the longitudinal limb of the skin incision. The horizontal limb of a T-shaped incision is marked in line with the gluteal fold (Fig 2). The entire extremity is prepared and draped in sterile fashion, with care taken to expose the area above the gluteal fold (Fig 3).
Fig 2 The horizontal limb of the T-shaped incision is marked in line with the gluteal fold (purple line).
Fig 3 The patient is placed prone on the operating table with all bony prominences padded. The entire extremity is prepared and draped in sterile fashion, with care taken to expose the area above the gluteal fold.
A T-shaped incision is made as previously marked. The incision may be extended proximally as necessary for safe exposure of the sciatic nerve and proximal hamstring tendons. Full-thickness skin flaps are dissected to the level of the deep fascia. The gluteus maximus is retracted superiorly. The deep fascia overlying the proximal hamstring is sharply incised, which allows for exposure of the paratenon and torn ends of the tendon. Commonly, a seroma may be encountered depending on the chronicity of the tear. Care should be taken to protect the posterior femoral cutaneous nerve at this stage of the procedure. Identification and neurolysis of the sciatic nerve comprise an important step, especially in symptomatic patients. Once the sciatic nerve is identified and protected, the ends of the tendon are identified, mobilized, and debrided of devitalized tissue (Fig 4, Video 1).
Fig 4 Intraoperative images during proximal hamstring reconstruction. (A) The proximal hamstring tendons (arrow) have been freed from chronic adhesions. (B) The sciatic nerve (asterisk) is visible with the hamstring tendons (arrow) reflected.
Attention is then turned to the ischial tuberosity preparation. This may be done through either an open or endoscopic approach. The ischial tuberosity is identified, and the proximal hamstring footprint is debrided to a bleeding bony bed. The anchors are placed in a diamond configuration with three 3.0-mm single-loaded SutureTak anchors (Arthrex, Naples, FL) placed in an inverted-triangle configuration and a 4.75-mm SwiveLock anchor (Arthrex) placed at the superior edge (Fig 5, Video 1).
Fig 5 (A) Endoscopic image of ischial tuberosity with anchor placement marked by electrocautery. (B) Pelvis model showing diamond configuration of anchor placement on ischial tuberosity.
The Achilles allograft is prepared by initially removing any calcaneus bone block. The remaining tendon is sutured using a FiberLoop suture (Arthrex) that is whipstitched through the end of the Achilles tendon allograft. The whipstitch should exit at the superior end of the allograft with 10 cm of suture tail present. The final pass of the whipstitch ensures that the remaining tail exits inferiorly on the graft. The position of the desired exit point will vary depending on the degree of retraction and soft-tissue loss of the native hamstring tendon. In the case presented, the exit point is shown at approximately half the length of the allograft. As with the proximal suture tails, at least 10 cm of suture tail should be present in the distal suture tails (Fig 6, Video 1).
Fig 6 Achilles allograft preparation with whipstitch. The superior end is the end that will be fixed to the ischial tuberosity during reconstruction.
Each limb of suture from the 3 SutureTak anchors is passed through the whipstitched allograft tendon in a similar inverted-triangle position, for a total of 6 suture limbs. The suture limbs should be kept separate to allow for knot tying (Fig 7). With tension held on these sutures, the allograft is shuttled to the ischial tuberosity footprint with the original looped suture and anchored with a 4.75-mm SwiveLock anchor in a knotless fashion (Fig 8). The remaining sutures are tied using an arthroscopic knot pusher to ensure adequate tension and contact of the tendon with the ischial tuberosity (Fig 9, Video 1).
Fig 7 Sawbones model (Vashon Island, WA) showing the passage of the SutureTak anchor tails through the Achilles allograft.
Fig 8 Sawbones model showing the shuttling process of the allograft into position using the SwiveLock anchor. The superiorly exiting whipstitch is passed through the SwiveLock anchor for this portion of shuttling.
Fig 9 Endoscopic image of ischial tuberosity during placement of SutureTak anchors in the inferior 3 positions of the previously shown diamond configuration.
The native proximal hamstring tendon is secured with a running Krackow stitch with No. 2 FiberWire (Arthrex), and the ends of this suture are tied to the proximal end of the original FiberLoop suture that was passed through the allograft (Fig 10). Flexion of the knee should be performed to maintain appropriate tension as these sutures are tied (Figs 11 and 12). Side-to-side sutures can be added for additional strength of the allograft to the native tendon construct (Video 1). A surgical technique overview is provided in Table 1. Pearls and pitfalls of this procedure are outlined in Table 2.
Fig 10 Sawbones model showing the Krackow stitch configuration in the proximal tendon stump. Two suture tails should be exiting from the stump once completed.
Fig 11 Sawbones model showing the docking of the proximal tendon stump with the allograft tissue. The Krackow suture tails of the stump are tied to the inferiorly exiting whipstitch on the allograft.
Fig 12 Intraoperative image showing the final reconstruction during testing of the construct. The knee is flexed and extended while the repair is directly visualized.
The patient was seen in the office by the senior author (J.J.C.) the day after surgery. The patient was weight bearing as tolerated with a walker for 6 weeks postoperatively. The patient was pre-fit for a hip orthosis (T-Scope Hip; Breg, Carlsbad, CA) by a trained medical equipment professional. The brace was set to allow full hip extension and 45° of hip flexion for the first 6 weeks. Daily mobilization with foot and ankle pumps was performed by the patient. Following in-office consultation with the senior author, the patient discontinued use of the walker at 6 weeks postoperatively. From week 6 to 12 postoperatively, the patient maintained wearing the brace unrestricted and was instructed to ambulate with caution and perform knee bending during toe-touch activities of daily living. Physical therapy focused on restoration of gait with gluteus and core isometrics. The patient returned to full pain-free athletic participation at 5 months postoperatively.
Surgical management of proximal hamstring avulsions, especially chronic injuries, can pose a significant challenge. The functional demand of the hamstring requires a biomechanically strong, anatomic repair to achieve successful tendon-to-bone healing. In a recent cadaveric study comparing 3 constructs for repair of complete proximal hamstring avulsions (2 small anchors, 2 large anchors, and 5 small anchors) with the intact proximal hamstring, the authors found that the repair using 5 small anchors provided similar strength to the intact proximal hamstring and was significantly stronger than either 2-anchor repair.^11^ They believed that the 5-anchor construct provided a more secure repair to the large footprint as opposed to “focally spot-welding” with only 2 anchors.^11^ We believe that our technique similarly uses sound biomechanical principles to better re-create the native anatomy and disperse forces with a diamond-configuration 4-anchor repair, although further biomechanical testing is needed. Identifying the appropriate position and location of the proximal hamstring footprint can be difficult in large open cases, but we believe using the endoscope to identify and mark the positions of the suture anchors provided a more anatomic repair.
The theoretical advantages of this approach over a large open approach include a lower risk of iatrogenic sciatic nerve injury, lower infection risk, and improved identification of the proximal hamstring footprint anatomy. A similar technique described the advantages of a dry endoscopic-assisted repair over an all-endoscopic repair to include a similar infection risk, a less technically demanding technique to achieve a more anatomic repair, and no risk of fluid extravasation.^12^ Further studies comparing the outcomes of fully open, all-endoscopic, and endoscopic-assisted surgical techniques are needed.
As with any surgical procedure, there are risks associated with the described intervention. This procedure does have specific risks and limitations that should be discussed with the patient prior to intervention aside from the general risks of surgery the use of allograft tissue and its potential for serving as a nidus for infection and/or disease transmission, the possibility of fibrous tissue formation that may limit functional outcome or reintroduction of scarring leading to sciatica symptoms in the affected extremity, and the risk of incomplete release of the scar tissue surrounding the sciatic nerve during the procedure. If the endoscopic method is used, care should be taken to ensure appropriate visualization is obtained and, if not possible, then conversion to more extensile exposure should be performed to ensure appropriate neurolysis and graft positioning are obtained.
Previous reports of allograft-augmented reconstructions of the proximal hamstring used extensive incisions and described difficulty in identifying the proximal hamstring footprint on the ischial tuberosity.^9^^,^^10^ We believe this endoscopic-assisted technique provides a safe and effective approach to achieve an accurate repair of the proximal hamstring while decreasing the risk of postoperative infection and iatrogenic sciatic nerve injury associated with more extensile approaches.