45 Semitendinosus Allograft Augmentation of Lateral Ankle Ligament Reconstruction Abstract Failure of rehabilitation for chronic lateral ankle ligament instability often requires surgical reconstruction. Direct anatomic surgical techniques (Broström–Gould) have been described with good long-term outcomes. There are certain situations where direct repair cannot be achieved or where the patient`s available tissue quality or underlying deformity would lead to high failure rates. In these situations, local repair can be augmented with near anatomic reconstruction utilizing allograft semitendinosus tendon. This avoids risking injury to the previously described utilization of the patient’s peroneus brevis tendon (Chrisman–Snook type procedures), which will weaken the dynamic stabilizers of the lateral ankle. An additional advantage is utilizing biologic tissue to enhance local tissue deficiency, positioned isometrically to optimize function and stability. Keywords: ankle instability, semitendinosus, allograft, augmentation, cavovarus, ligament laxity • Recurrent deformity from failed modified Broström type anatomic reconstruction. • Recurrent deformity from nonanatomic split peroneus brevis reconstruction. • Poor local tissue quality due to generalized ligamentous instability (Ehlers–Danlos syndrome). • Severe varus ankle deformity (varus talar tilt >30 degrees based on weight-bearing radiographs) with complete loss of locally usable tissue. • Severe hindfoot varus deformity with concomitant lateral ankle ligament instability. • Associated high-grade tears of their peroneus brevis tendons requiring reconstruction with concern that the dynamic stabilizer of the ankle would be suboptimal and augmentation utilizing an allograft would be beneficial. • Lateral ankle ligament instability. • Recurrent sprains of the ankle. • Associated pathology (described earlier) precluding direct anatomic repair. • Recurrent ankle sprains. • History of failed physical therapy. • History/family history of generalized ligamentous instability: • History of prior surgical reconstruction. • Lateral ankle ligament instability: • Scars from previous surgical repairs may be present. • Peroneus brevis dysfunction/pain/weakness despite adequate therapy. • Evaluate for associated cavovarus deformity. • Evaluate for generalized ligamentous instability: • Weight-bearing ankle and foot radiographs should be obtained: • Magnetic resonance imaging (MRI): • Physical therapy with focus on peroneal strengthening and proprioception training. • Brace immobilization: • Activity modification. • Immune compromise (high risk for allograft transplantation). • History of or active perioperative site infection. • Inadequate bone stock for required bone tunnels (usually fibular). • Severe ankle arthritis requiring arthrodesis (in patient who is not a candidate for ankle arthroplasty that can be performed concomitantly with this procedure). • Lasting stability of the lateral ankle ligamentous complex. • Maintenance of ankle function and range of motion. • Prevention of recurrent ankle instability. • Fresh frozen allograft can be utilized. • This is freely available in most institutions. • No immune typing or cross-matching is required. • No donor site morbidity. • Allows anatomic positioning of bone tunnels for ligament reconstruction. • Anatomic positioning of bone tunnels: • Adequate length on semitendinosus allograft. • Interference fixation into bone tunnels. • Fixation in ankle eversion with maximal tightness of allograft. • Procedure can be performed in isolation, or combined with anatomic ligament repair. • Lateral or sloppy lateral position with a wedge or beanbag under the ipsilateral hip. • Calf or thigh tourniquet can be used. • Concomitant procedures are carried out as needed. • The exposure for the reconstruction is dependent on associated procedures. • Different tendon allograft can be used. The semitendinosus tendon is optimal due to the length of the tendon, which should be at least 20 cm long. • The allograft is thawed and soaked in antibiotic solution prior to use. • On the back table, a whipstitch is run through each end of the tendon, tubularizing the tendon (Fig. 45.2). • A “Chinese finger trap” wrapping suture can be placed around the tendon end with absorbable suture to bullet-tip the end of the tendon and prevent fraying and jamming of the tendon during passage through the bone tunnels. • Suture ends are left long to pull and tension the tendon through the bone tunnels. • We usually manually pre-tension the tendon prior to implantation, but the necessity for this remains controversial. • The thickness of each end of the tendon is measured utilizing a known diameter measuring system (Fig. 45.3). Fig. 45.1 (a) Incision planning for primary procedure with small incision anterior to fibular over anterior talofibular ligament (ATFL) insertion. (b) More extensive lateral incision is made when repair of the peroneal tendons is required. Fig. 45.2 Semitendinosus allograft of adequate length with locking stitches at each end.
45.1 Indications
45.1.1 Pathology
45.1.2 Clinical Evaluation
History
Ehlers–Danlos syndrome.
Marfan’s syndrome.
Recurrent joint instability (shoulder, patella, etc.).
Examination
Positive anterior drawer test.
Positive varus stress test.
Beighton score > 6/9.
45.1.3 Radiographic Evaluation
May be normal in many cases.
Evaluate for cavovarus deformity (hindfoot or forefoot driven).
Varus talar tilt >30 degrees (without additional varus stressing of the ankle).
Assess for associated pathology:
Peroneal tendon pathology.
Osteochondral lesions talus.
Ankle/hindfoot arthritis.
45.1.4 Nonoperative Options
Semi-rigid ASO (Ankle Stabilizing Orthosis) brace usually insufficient for these severe instability cases.
Rigid ankle–foot orthosis (AFO; Arizona brace or molded ankle–foot orthosis [MAFO] brace) usually required.
45.1.5 Contraindications
45.2 Goals of Surgical Procedure
45.3 Advantages of Surgical Procedure
45.4 Key Principles
Anterior talofibular ligament (ATFL) footprint in talus.
ATFL insertion into fibular.
Common flexor tendon (CFT) insertion into fibular.
CFT attachment into calcaneus.
45.5 Preoperative Preparation and Patient Positioning
45.6 Operative Technique
If this is the primary procedure, as with cases of Ehlers–Danlos syndrome where the local tissue quality is known to be deficient, a more percutaneous approach can be used. Four small incisions are utilized, one over the ATFL insertion footprint into the talus, a second at the ATFL insertion into the anterior distal fibular, one posterior to the distal fibula, and a final incision over the lateral calcaneus at the calcaneofibular ligament (CFL) insertion (Fig. 45.1a).
If peroneal or lateral ankle joint exposure is required, the procedure is performed through a curvilinear incision along the path of the peroneal tendons, posterior to the fibula. The flap is elevated in order to gain access to ATFL and CFL (Fig. 45.1b).
45.6.1 Graft Preparation
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