SURGICAL MANAGEMENT OF CHRONIC RUPTURES OF THE ACHILLES TENDON
January 7th, 1997
Jeffrey N. Kann, MD and Mark S. Myerson, MD
Patients who sustain a rupture of the Achilles tendon are frequently treated immediately after injury. Early intervention, whether operative or nonoperative, usually leads to good functional outcomes.6,7,9 However, because of the strength of the muscles of plantarflexion of the foot, the extent of the acute injury may not always be appreciated. Plantarflexion is possible using the long toe flexors, as well as the posterior tibial and peroneal muscles, all of which provide modest plantarflexion strength. Unlike the acute tear of the Achilles tendon, neglected or insufficiently treated ruptures are far more difficult to manage on a delayed basis (>2 months postinjury). At about 10 days after the injury, any gap between the torn tendon ends begins to fill with fibrous scar tissue, which does not have the same contractile strength as the normal tendon. The fibroblasts are disorganized and not longitudinally oriented. This disorganized scar will gradually stretch and elongate as it is unable to withstand the tensile forces applied by the gastrocnemius-soleus complex. Although the tendon may occasionally heal in continuity in an elongated position, a long-standing rupture more commonly results in a gap whose length is determined by the amount of retraction of the proximal stump. Daily activities such as walking are compromised, and any exercise, including running, jumping, and stair climbing, may be quite difficult or even impossible.
Many techniques for repair of the chronic Achilles tendon rupture have been proposed.4,5,10,11,16,17,19 These have included autologous as well as synthetic material. Bugg and Boyd4 used multiple strips of fascia lata, whereas Bosworth3 turned down a strip of the proximal Achilles tendon. Lynn11 used the plantaris tendon to reinforce his repair, and Turco and Spinella19 used a peroneus brevis transfer to augment the repair. Synthetic material such as carbon fiber5 and marlex mesh15 have also been used as a bridge between the torn tendon ends. Mann et al14 recommended the use of the flexor digitorum longus (FDL) to supplement the repair and Wapner et al20-22 used the flexor hallucis longus (FHL) to repair a chronic Achilles rupture.
Our decision-making about which technique to use for chronic Achilles ruptures is based on: 1) the distance between the tendon ends, 2) the age of the patient, 3) the length of time elapsed, and 4) athletic activity.
It is helpful to plan the extent of surgery preoperatively. To this end, one should attempt to palpate the tendon ends and, hence, determine the size of the gap so that the technical aspects of surgery can be planned accordingly. Although this gap can usually be clinically determined, magnetic resonance imaging or ultrasound will adequately document the size of the defect. In our practice, both limbs are prepped in the operative field so that, with the patient lying prone, the resting tension on the Achilles repair may be compared with that of the normal foot.
A tourniquet is optional for all procedures and, if used, should be applied to the thigh to avoid tethering the gastrocnemius-soleus complex, which will prevent the proximal stump from being pulled distally. Wound closure after any of the procedures described below must be performed carefully to avoid subsequent skin necrosis. The paratenon should be repaired when possible to help maintain the blood supply to the tendon, followed by wound closure in layers. One of the problems we encounter, regardless of the length of time elapsed since the acute injury, is difficulty with wound closure, with subsequent less than optimal results. We now routinely perform a fasciotomy of the posterior compartment of the leg, which increases the horizontal or cross-sectional diameter of the tissue envelope, thereby facilitating skin closure performed with a dermal mattress suture of 4-0 nylon. The lower leg is immobilized in a bulky dressing, incorporating splints to hold the ankle in a neutral position. A neutral position is preferred after all reconstructive procedures unless the ankle is intentionally placed in equinus to facilitate end-to-end repair of smaller gaps between the tendon ends.
The postoperative course is identical for all of the different procedures. We emphasize a functional rehabilitation with early mobilization and strengthening.
Defects of 1 cm
For minimal defects, it is possible to accomplish a repair without any augmentation. The muscle can usually be mobilized and the repair performed with the foot held in mild equinus. This equinus position is not usually a long-term problem since the foot gradually assumes a plantigrade position during rehabilitation. Ideally, however, normal function is preferable, which mandates full dorsiflexion. Perfect end-to-end apposition is important and the repair is not different from that which we have described in detail elsewhere8,12,13. The key to this repair is adequate internal fixation followed by aggressive rehabilitation to maximize isokinetic function.
The surgery is performed on an outpatient basis. The patient is given a general anesthesia and positioned prone. A posteromedial incision is used to avoid the sural nerve, which can be very sensitive if traumatized, and to take advantage of the plantaris tendon, if present, since it may be used to augment the repair. The dissection is taken to the level of the paratenon, thus ensuring thick flaps. The paratenon is opened 3 cm above to 3 cm below the defect. The rounded, slightly bulbous ends of the tendon are cut sharply, removing the fibrous scar and creating a flat surface for apposition. The repair is performed with a no. 2 nonabsorbable polyfilament suture using a whip suture technique as previously described.8,12,13 The sutures are tied anteriorly (deep) to prevent the knots from being in a prominent subcutaneous position. The paratenon is repaired using a 4-0 absorbable suture.
Postoperatively, patients are allowed to commence range-of-motion exercises once the sutures are removed (at approximately 2 weeks). Weight-bearing commences at this time in a removable hinged range-of-motion walker boot that allows complete flexion of the ankle but has a dorsiflexion block that can be adjusted during the recovery process. We emphasize range-of-motion of the ankle, early weight-bearing, and functional rehabilitation, including plantarflexion strengthening exercises.
Defects of 1 to 2 cm
The principle of this procedure is similar to that described above, but reliance is placed on the tensile properties of the muscle tendon unit to achieve end-to-end tendon apposition. The exposure and method of suture is identical to that described above. Once the sutures are inserted, tension (approximately 20 pounds of pressure) is then applied for 10 minutes to "stress relax" the myotendinous junction. If the surgeon cannot maintain this pressure, a weight that is tied to the proximal tendon sutures may be suspended over the end of the table. This technique is quite reliable and will gain up to 2 cm in length, depending on the elastic properties of the tissue. The ankle is then placed in the desired amount of plantarflexion and a direct end-to-end repair is performed as previously described. After skin closure, the lower limb is immobilized in a neutral position; although slight plantarflexion is permissible, it is not preferred nor ideal. The postoperative management is similar to that described above.
Defects of 2 to 5 cm
For defects of this magnitude, we use the FHL transfer, a technique popularized by Wapner et al.20-22. The FHL is stronger than the FDL or peroneal muscles, and its strength and excursion are compatible with its function as a transfer. The relative strengths and excursions of the muscles of the foot and ankle were delineated by Silver et al18 who showed that the FHL was the second strongest plantarflexor next to the gastrocnemius-soleus complex: gastrocnemius-soleus complex, 49.1%; FHL, 3.6%; peroneus brevis, 2.6%; and FDL, 1.8%. In addition, the contractile axis of the FHL most closely approximates that of the Achilles and its anatomic proximity to the Achilles facilitates the repair.
Surgery may be performed under either general or regional anesthesia (our preference). The patient is positioned slightly laterally, with the affected side down and the ipsilateral hip and knee flexed, since this aids in the exposure. The skin marking for the incision on the foot corresponds to the talonavicular joint proximally and the midportion of the first metatarsal distally (Fig. 1). The plane of the dissection is deep to the abductor hallucis and flexor hallucis brevis, which are reflected plantarward. The FHL and FDL are identified, with the FHL being the more medial structure (Fig. 2). The medial plantar branch of the medial plantar nerve can be damaged with this dissection and must be retracted. To prevent proximal and distal retraction of the FHL tendon ends, once cut, two sutures are inserted into the FHL tendon, 1 cm apart at the level at which the FHL is to be cut (Fig. 3). The FHL and FDL are sutured by tenodesis of the distal stump of the FHL together distally with the ankle and toes in a neutral position (Fig. 4). The range of motion of the hallux is assessed and, unless full dorsiflexion of the hallux is possible after the tenodesis, the sutures must be changed to adjust the tension on the stump of the FHL. More proximally, at the level of the foot where the FHL and FDL tendons cross each other (the Knot of Henry), there are multiple fibrous cross-connections between these tendons that usually need to be released for the FHL to be pulled into the proximal wound.
A second incision is made along the medial border of the Achilles tendon from the myotendinous junction to 2 cm distal to the Achilles insertion. The deep posterior compartment of the leg is then opened longitudinally and the FHL muscle is identified. The FHL tendon is pulled into the proximal wound. At times, it is necessary to open the flexor retinaculum as far distal as the sustentaculum tali to permit the tendon to pass into the proximal wound. A 4.5-mm drill hole is made 1 cm distal to the Achilles tendon insertion and 1.5 cm anterior to the posterior margin of the calcaneal cortex from medial to lateral (Fig. 5). A 1-cm incision is made on the lateral posterior margin of the heel posterior to the sural nerve and immediately over the drill hole. The tendon is then passed from medial to lateral, and then through a subcutaneous tunnel over the dorsal cortex of the calcaneus. In the past, we have tried drilling two holes, made at 90o to each other, but this construct is markedly tenuous, and fracture of the calcaneus may occur. A suture passer may be used to pull the tendon of the FHL from proximal to distal through the drill hole. Alternatively, the end of a small metallic suction tip is passed from lateral to medial and the suture on the FHL is sucked into the tip, facilitating passage from medial to lateral. The FHL is then woven through the Achilles tendon from distal to proximal for the length of the FHL. The FHL is sutured to the Achilles with 2-0 nonabsorbable monofilament, and the muscle is sutured to the Achilles with 2-0 absorbable suture (Fig. 6). The Achilles is therefore used in the final repair, regardless of the length of time since rupture, in the hope that the gastrocnemius-soleus muscle will augment the transfer. This is an important step, and integral to the final outcome. The FHL, while strong, is markedly weaker than the gastrocnemius-soleus, and alone cannot be expected to return the patient to full activity.
The construct is tensioned with the ankle in neutral flexion. Closure is performed as previously stated with the foot held in neutral flexion, although slight equinus is permissible. At the completion of the repair, the foot is taken through a full range of motion, and the ability of the construct to withstand dorsiflexion beyond neutral is carefully checked. The postoperative routine is identical to that described above for chronic rupture repair techniques.
Defects >5 cm
For massive defects, we use a V-Y myotendinous lengthening, as described by Abraham and Pankovich1 augmented with the FHL transfer just described. As originally described, this procedure reportedly corrected strength deficit when performed without the addition of the FHL transfer.1 However, in using this procedure in the past,1 we have determined that the repair is tenuous and not compatible with early range of motion. Furthermore, it compromised rehabilitation and impeded the ultimate return of power, strength, and full function. Although the FHL may be used as the sole transfer for these massive defects, as described above, we have found that it is insufficient by itself. Despite attritional atrophy of the gastrocnemius-soleus muscle, sufficient function remains, so that even in chronic cases, the combined procedure works well.
Either general anesthesia or a combined peroneal-popliteal block is used, but the patient must be in the prone position. The FHL is harvested as previously described. A long incision is made, beginning proximal to the myotendinous junction in the midline, gently curving posteromedial to the Achilles tendon, and ending distal to the tendon insertion. The length of the defect after debridement of the tendon ends must be determined. An inverted V incision is made in the fascia of the gastrocnemius, leaving the underlying muscle attached to the anterior paratenon. The length of the arms of the inverted V should be twice as long as the defect (Fig. 7). The flap is then gently advanced and an end-to-end repair is performed using the whip suture as previously described8,12,13 (Fig. 8). The Y is then closed with 2-0 nonabsorbable suture. The FHL is then passed through drill holes in the calcaneus and weaved through the Achilles tendon as described above. Routine closure is performed and a bulky splint in 10 to 20o of plantarflexion. Postoperative rehabilitation is performed as described above.
The main complications associated with delayed repair of the Achilles tendon are wound necrosis, rerupture, infection, and inability to gain dorsiflexion. Wound-edge necrosis can best be avoided by using meticulous soft-tissue handling techniques, full-thickness flaps, and routine use of the posterior fasciotomy. In addition, a bulky, cotton dressing with a posterior splint should be used to minimize initial motion pressure on the wound.
The above-described surgical, postoperative, and rehabilitative techniques make rerupture unusual; to date, we have not experienced this complication.
Infection can be devastating if full-thickness necrosis occurs, exposing the tendon. In this case, the tendon must be kept constantly moist to avoid desiccation by using regular wet-dressing changes with oral antibiotics and permitting healing by secondary intention. Attinger et al2 described an alternative method of wound management that uses the application of silvadene dressings followed by split-thickness skin grafting over the granulating surface.
Ankle stiffness can best be avoided by a regimented postoperative rehabilitation course and ensuring that the repair does not require the ankle to be placed in excessive plantarflexion. Perhaps a more clinically significant complication is the lack of either free motion or the ability to regain adequate push-off strength. Either of these may be caused by incorrect tensioning of the repair or elongation of the repair construct postoperatively. Ankle stiffness results from insufficient length because the repair must be made with the foot held in equinus; yet this position is far less compromising than if the repair were performed in a functionally elongated position. Push-off strength is never fully regained for this patient.
The chronic or neglected Achilles tendon rupture poses a difficult problem for the orthopaedic surgeon. Most patients will complain of an inability to perform a single toe-stance/heel-rise, weakness at push-off of the gait cycle, and the inability to participate in recreational sports due to lack of strength. Bracing with a spring-loaded, hinged ankle/foot orthosis can improve function and power at push-off, but will not permit the patient to perform toe-rises.
The etiology of the chronic rupture can be multifactorial, including missed initial diagnoses, inappropriate treatment of an acute rupture, chronic Achilles tendinosis leading to microtears with subsequent lengthening, and ruptures associated with inflammatory disorders, such as rheumatoid arthritis and systemic lupus erythematosus. Ruptures in patients with inflammatory disorders can be very difficult to diagnose and treat. Such patients frequently have multijoint involvement (causing a decreased range of motion and weakness), are on multidrug regimens (often including steroids that which can increase the risk of postoperative complications), and can sustain spontaneous ruptures that may be undetected for years.
We believe that there is no time limit beyond which a repair of a chronic rupture will not improve function. Regardless of the etiology, the size of the defect, and the time since rupture, the decision-making algorithm and repair techniques outlined above provide patients with improved strength, function, and power, and freedom from a brace. It must, however, be remembered that the patient must be motivated toward an aggressive rehabilitation course and be compliant with such a regimen.
1. Abraham E, Pankovich AM: Neglected rupture of the Achilles tendon. Treatment by V-Y tendinous flap. J Bone Joint Surg 57A:253, 1975
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Chronic ruptures of the Achilles tendon pose a formidable problem for the orthopaedic surgeon. These chronic tears result in either lengthening from scarring or a large fixed gap. The patient with this disorder is quite debilitated due to substantial decrease in push-off strength. They often have difficulty with simple, everyday tasks such as stair-climbing and rising on their toes. Treatment modalities include various operative and nonoperative techniques. Our protocol for treating the chronic Achilles tendon rupture is described.
Fig. 1. Schematic representation of the medial incision corresponding to the talonavicular joint proximally and the midportion of the first metatarsal distally.
Fig. 2. The abductor hallucis and flexor hallucis brevis muscles are reflected plantarward. This exposes two tendons: the more medial tendon is the FHL; the more lateral is the FDL.
Fig. 3. Once the FHL is identified, two sutures are placed 1 cm apart at the level at which the FHL is to be cut.
Fig. 4. The distal stump of the FHL is sutured to the FDL with the foot and ankle in neutral position. It is at this point that one must check the motion of the hallux. If full dorsiflexion cannot be achieved, then the tenodesis must be adjusted more distally.
Fig. 5. After the FHL has been mobilized into the proximal wound, a 4.5-mm drill hole is made 1 cm distal to the insertion of the Achilles tendon and 1.5 cm anterior to the posterior calcaneal cortex (medial to lateral).
Fig. 6. The FHL is pulled form medial to lateral through the drill hole. Then a subcutaneous tunnel is made over the dorsal cortex of the calcaneus, and the FHL is woven through the Achilles tendon from distal to proximal for the length of the FHL. The FHL tendon and muscle are sutured to the Achilles.
Fig. 7. After exposure, an incision is made in the fascia of the gastrocnemius. The length of the arms of the inverted V should be twice as long as the defect.
Fig. 8. The V is then advanced and an end-to-end repair is performed. The Y is closed with a 2-O nonabsorbable suture. The FHL is then woven through the Achilles tendon as previously described.