Achilles Tensioning and Anchor Insertion
The ankle is plantar flexed to tension the Achilles tendon relative to the contralateral limb and is held in place by an assistant (Figures 4A-4E).
Position of the drill holes can be rechecked with a Kirschner wire before anchor insertion, as their relative position changes with ankle plantar flexion. It is not necessary to premeasure and adjust suture length at the tip of the anchor as in other blind tunnel anchor insertion techniques (eg, InternalBrace; Arthrex). Once the anchor tip is malleted into bone, the free suture ends are released to avoid overtensioning the tendon. Before the anchor insertion handle is completely removed, the tip of a mosquito clamp can be used to feel the bony surface and confirm the anchor is completely seated.
With the ankle still held in the appropriate amount of plantarflexion, the process is repeated and the other SwiveLock anchor inserted. Sutures are cut flush with the anchor, and the surgeon performs wound irrigation and layered closure, with absorbable suture, of the paratenon and subcutaneous tissues. After skin closure with nylon suture, resting ankle plantarflexion is assessed and the Thompson test performed. The patient is placed in a well-padded non-weight-bearing plantar flexion splint for incision and initial tendon healing during the first 2 weeks after surgery.
Discussion
A key aspect of recovery is the balance achieved between skin and tendon healing and early mobilization, as outcomes of surgical repair of Achilles ruptures are improved with early weight-bearing and functional rehabilitation.11-13 Some surgeons recommend weight-bearing immediately after surgery, given the direct tendon-to-bone fixation achieved with repair.9 I prefer 2 weeks of non-weight-bearing, which allows the skin to heal adequately and the initial soft-tissue inflammation to subside. If the incision is healed at 2 weeks, sutures are removed, and the patient is transitioned to a tall, non-weight-bearing CAM (controlled ankle motion) boot, worn for 1 to 2 weeks with initiation of gentle ankle range-of-motion exercises. If there is any concern about wound healing, sutures are maintained for another 1 to 2 weeks.
Between 3 and 8 weeks after surgery, progressive weight-bearing is initiated with a peel-away heel lift (~2 cm thick total, 3 layers). Each lift layer is removed as pain allows, every 2 to 3 days. The goal is full weight-bearing with the foot flat 5 to 6 weeks after surgery. Physical therapy focusing on ankle motion and gentle Achilles stretching and strengthening is started 5 to 6 weeks after surgery, depending on progression and functional needs. Between 8 and 12 weeks after surgery, the patient is transitioned to normal shoe wear with increased activities. Running and jumping are allowed, as pain and swelling allow, starting at 12 weeks.
Although preliminary outcomes and experience with the Achilles Midsubstance SpeedBridge have been favorable, long-term clinical and functional studies are needed to determine the specific advantages and disadvantages of this new technique relative to other repairs. The main benefits observed thus far are reduced subjective knot tying and tensioning, decreased reliance on suture fixation in compromised tissue at the rupture site, reduced risk of FiberWire knot irritation of superficial soft tissues, lower risk of distal suture pullout, and earlier mobilization owing to bony fixation of the tendon. Potential complications include anchor-site heel pain caused by prominent anchors or by the bone edema that occurs when a patient increases physical activity by a significant amount at 12 weeks.9 Heel pain caused by bone edema resolves by 20 weeks without intervention.
Stress shielding of the distal Achilles tendon is a theoretical concern given the tendon–bone construct, but there have been no reports of tendon atrophy or repair failure caused by stress shielding. The original PARS technique was often used to create Achilles tension with the ankle maximally plantar flexed—the idea being that the tendon would gradually stretch over time.1 Overtensioning the Achilles repair is a potential complication with the SpeedBridge, as the distal anchors provide a more rigid point of distal fixation. Surgeons can avoid this complication by cycling the sutures to remove any residual creep and then tensioning the Achilles according to the contralateral limb and/or palpating tendon opposition at the rupture site.
Overall, this new limited-incision knotless Achilles tendon repair technique allows for minimal soft-tissue dissection, restoration of Achilles musculotendinous length, and direct tendon-to-bone fixation. Early results are promising, but long-term clinical outcomes and comparative analysis are needed. In addition, many details of this technique must be clarified—including incidence of short- and long-term complications in larger cohorts, optimal suture material and configuration, and risks and benefits of immediate (<2 weeks) and delayed (2-4 weeks) weight-bearing.
Am J Orthop. 2016;45(7):E487-E492. Copyright Frontline Medical Communications Inc. 2016. All rights reserved.