Endoscopic-Assisted Hamstring Tendon Harvesting

An instrument originally designed for endoscopically assisted decompression of the ulnar nerve is used (R. Wolf GmbH, Knittlingen, Germany), called the optical dissector. This instrument is designed with a “handling” handle at one end and a hollow retractor at the other end (Fig 1 A and B). A 30° or, preferably, a 70° arthroscope is inserted into the sheath of the device to facilitate endoscopic vision. The patient is positioned on the operating table in the supine position, usually without the use of a tourniquet. A padded thigh post and a L-shaped footrest allow the knee to be positioned at 90° of flexion. A vertical or oblique 3- to 4-cm long skin incision is performed, centred over the pes anserinus, between the tibial tubercle and the posteromedial edge of the tibia. The pes anserinus fascia is opened bluntly and elevated using a small Kocher clamp and the distal attachments of both the semitendinosus and the gracilis tendons are isolated using a cotton tape. The optical dissector is inserted into the pes anserinus with the surgeon holding the device with one hand elevating the pes and the subcutaneous tissue. The medial collateral ligament is clearly identified by its white, dense fibers running in a vertical direction, crossed by the hamstring tendons. The gracilis tendon crosses the medial collateral ligament at a 70° to 80° angle. The surgeon is using with the other hand a 20-cm long Metzenbaum scissors to palpate the fascial attachments and divide them under direct endoscopic vision (Fig 2). At the same time, the assistant applies longitudinal traction to the tendon with a blunt hook or the cotton tape, facilitating fascial band exposure and tendon liberation. The Metzenbaum scissors are used with their curved end toward the tendon to avoid inadvertent tendon injury. The entire tendon length is visualized from the tibial attachment to the musculotendinous junction, where several bands may exist that hinder advancement of the tendon harvester. Resistance at the muscle–tendon junction may be due to the presence of fascial bands. All tendon bands and attachments are divided under direct vision. Occasionally, large vessels are encountered, which can be coagulated. The gracilis tendon enters the respective muscle belly through a fascial arcade, which is palpable but difficult to dilate blindly (Fig 3A). If the fascial arcade is narrow, it can be released under direct vision to facilitate insertion of the tendon stripper (Fig 3 A and B). Next, the assistant holds the optical dissector, and the surgeon applies tendon traction while inserting the tendon stripper (Fig 4). The stripper is pushed proximally into the muscle belly aiming at the inferior ischiopubic ramus. When an open tendon stripper is used, no rotation is allowed to avoid disengagement or tendon injury. The whole length of the gracilis tendon is harvested and wrapped in an antibiotic-soaked sponge.

The next step is harvesting of the thicker and stronger semitendinosus tendon. The tendon is visualized and a blunt hook is passed around it. The semitendinosus tendon has usually 2 main bands; one is distal and close to the skin incision and the other proximal, connecting the tendon with the fascial overlying the medial head of the gastrocnemius. Failure to release the latter, broad and strong band, may lead to graft amputation. The optical dissector is inserted into the surgical wound following the semitendinosus tendon while the assistant applies steady traction. Both fascial bands are recognized und dissected under direct vision (Fig 5 A-C). The musculotendinous junction of the semitendinosus tendon is visualized, and the entrance of the tendon is enlarged. The tendon stripper is inserted and pushed towards the musculotendinous junction in line with the tendon aiming towards the ischial tuberosity. Advancement of the stripper into the muscle belly is accompanied by steady traction applied to the tendon via the hook until the tendon is liberated. Finally, the tendons are freed and cut at their distal insertion. Alternatively, the distal tibial attachments of the hamstring tendons can be released to use a closed tendon stripper.

Alternatively, to avoid the use of the optical dissector, a Langenbeck retractor with a 15-cm long blade is inserted in the pes anserinus sheath, and the assistant elevates the pes anserinus sheath and the subcutaneous tissue facilitating tendon exposure (Fig 6). The retractor is used to create space, leaving only the hamstring tendons at the deeper aspect of the surgical wound. The assistant applies longitudinal traction to the tendon with a hook to assist in the exposure of the fascial bands. The surgeon inserts a 30° or, preferably, a 70° arthroscope into the pes anserinus without its sheath along the course of the gracilis tendon. The scope is held in contact with the retractor to improve viewing stability. Further dissection is performed with a pair of long Metzenbaum scissors, freeing all fascial bands under direct vision until the musculotendinous junction. The tendon stripper is then inserted, and the tendon is harvested under direct vision. The same procedure is repeated to harvest the semitendinosus tendon. This technique is feasible only in patients with minimal amount of subcutaneous fat and it is more difficult and time consuming. A major problem with this method is that the arthroscope fogs immediately when it is inserted in the surgical wound. Warming the scope by inserting it in sterile, warm saline delays fogging.

At the end of the harvesting procedure, the skin is infiltrated with a long-acting local anesthetic, which is also injected deep into the wound using a Tieman catheter. Closure of the skin incision is performed in layers using absorbable sutures.