Steven M. Raikin
DEFINITION
Achilles tendon rupture results in loss of plantarflexion function of the ankle through disruption of the gastroc–soleus–Achilles (GSA) mechanism.
Chronic rupture is usually defined as a rupture not appropriately treated within 8 weeks of injury.
Chronic or neglected ruptures result in retraction of the proximal myotendinous portion and diastasis between the ruptured tendon ends.
Functional deficits result from loss of plantarflexion strength and dorsiflexion; check reign of the GSA mechanism.
This chapter presents a combined reconstruction and augmentation technique for repairing chronic or neglected Achilles tendon ruptures.
ANATOMY
The triceps surae complex is composed of the two heads of the gastrocnemius and the soleus muscle combining to form a single tendon—the Achilles tendon, making up the GSA complex.
The GSA complex originates from the distal femoral condyles and inserts into the posterior calcaneal tuberosity, making it one of the few muscle–tendon complexes to cross three joints (knee, ankle, and subtalar joints) in the human body.
The tendon is loosely surrounded by a paratenon, which allows the tendon to slide about 1.5 cm.
The blood supply to the tendon emanates from the muscle proximally and the calcaneal insertion distally, leaving a watershed area of relatively avascular tendon 4 to 5 cm from the calcaneal insertion.2,3
PATHOGENESIS
Seventy-five percent of Achilles tendon ruptures occur during sporting activities.
A history of prior Achilles tendinitis is present in about 15% of ruptures.
Ruptures occur most commonly in the 30to 40-year age group, with a male predominance.
Eighty percent of Achilles tendon ruptures occur in the watershed area 2 to 6 cm above the insertion.
Mechanism of injury resulting in rupture can be forceful plantarflexion or hyperdorsiflexion of the ankle.
Achilles tendon ruptures are frequently missed or misdiagnosed as ankle sprains on initial assessment.
Failure of immobilization or repair will allow continued contracture of the gastrocsoleus muscle, resulting in retraction of the proximal myotendinous portion of the GSA complex and subsequently in the development of a gap between the tendon ends.
NATURAL HISTORY
Missed or neglected ruptures of the Achilles tendon result in plantarflexion weakness and loss of the dorsiflexion; check reign of the GSA complex.
Without treatment patients develop gait dysfunction, particularly walking up stairs, inclines, or ladders, as well as balance difficulties, with a tendency to fall forward.
PATIENT HISTORY AND PHYSICAL FINDINGS
Patients frequently recall the primary event, and often describe feeling like they had been “shot” or “hit” on the back of the heel when the rupture occurred.
Silent or spontaneous ruptures may occur in the presence of systemic inflammatory diseases, steroid use, or chronic underlying Achilles tendinosis.
Patients are usually able to walk on the limb and plantarflex the ankle without significant pain despite the chronic rupture.
Primary complaints are:
Weakness of plantarflexion (walking up inclines, stairs, ladders)
Gait and balance difficulties
Clinical examination
Inability to walk on tiptoes
Inability to perform a single-leg toe raise (difficulty with double-leg raise)
Direct evaluation should be performed with the patient lying prone with both knees flexed to 90 degrees (both sides are examined and compared):
Decreased resting tension of the Achilles tendon (normal resting tension of the unaffected side holds the ankle at 20 to 30 degrees of plantarflexion, while the ruptured side will usually be neutral [zero degrees plantarflexion]).
Hyperdorsiflexibility of the ankle compared to the unaffected side
Plantarflexion may be present (due to the effect of the posterior tibial tendon, flexor hallucis longus [FHL], and digitorum longus, and the peroneal tendons) but is weaker than the unaffected side.
A palpable gap may be present between the ruptured tendon ends (FIG 1) when the tendon is followed from the insertion proximally. Careful palpation can usually detect the proximal end, and the gap can be estimated, although it is difficult to measure clinically.
The Thompson test (squeezing the calf) will not result in symmetrical ankle plantarflexion (compared to the unaffected side), although some degree of plantarflexion is usually present in chronic rupture cases.
FIG 1 • A large palpable gap can usually be felt between the ruptured ends.
IMAGING AND OTHER DIAGNOSTIC STUDIES
The diagnosis of an Achilles tendon rupture (acute or chronic or neglected) can usually be made on careful clinical evaluation alone.
If one is uncertain or wishes to better quantify the rupture gap, ultrasound or MRI can be performed.
Both tests are highly reliable in confirming the diagnosis and in obtaining an accurate measurement of the gap.
No difference in diagnostic accuracy has been shown, although the MRI may yield more information about the degree of atrophy and fibrosis within the gastrocsoleus muscle.
This will not affect the treatment options but may help prognosticate the outcome of reconstruction.
MRI evaluation is useful in neglected ruptures to quantify the gap between the tendon ends.
NONOPERATIVE MANAGEMENT
Brace management can be used for patients who are not candidates for surgical reconstruction.
These include patients with medical risk factors, poor distal circulation, and impaired wound healing potential (including patients on steroids or immunosuppressive medications, and those with diabetes mellitus).
Patients with more moderate functional deficits, with low physical demands, may choose nonsurgical management.
Management consists of a custom-molded ankle–foot orthosis (MAFO) made of polypropylene.
An ankle hinge spring-loaded MAFO can be fashioned to add plantarflexion torque and further aid push-off.
Long-term braces tend to be poorly tolerated in many patients with more active lifestyles.
SURGICAL MANAGEMENT
The choice of surgical reconstruction depends on the size of the rupture gap. The ability to mobilize the retracted muscle tends to be the major limiting factor.
Defects less than 1 cm can usually be mobilized and repaired with end-to-end anastomosis.
For defects of 1 to 3 cm, direct end-to-end anastomosis can usually be obtained. Stretching of the retracted muscle is usually required via longitudinal traction over about a 10-minute time period to close the gap.
Defects of 3 to 7 cm require an advancement procedure of the Achilles tendon, performed as a V-to-Y lengthening. Further augmentation with a FHL tendon transfer results in additional strength and function of the repair. This technique will be outlined in more detail below.
For defects of more than 7 cm, reconstruction involves either an Achilles turndown procedure (if enough tendinous tissue is available proximally) or an allograft replacement of the Achilles tendon.
Preoperative Planning
MRI or ultrasound should be reviewed to determine the gap size and to aid in the location of the ruptured ends (FIG 2).
Examination under anesthesia should be performed as described above.
General endotracheal or spinal anesthesia can be used for this procedure.
Surgery is usually performed on an outpatient basis.
Positioning
Once the patient is anesthetized, a well-padded thigh tourniquet should be applied.
It is technically easier to apply the tourniquet while the patient is still in a supine position.
The surgeon must ensure that the connection for the tubing is placed posteriorly or laterally to allow attachment after positioning, and to prevent pressure problems from the patient lying on the connection or tubing.
A calf tourniquet should not be used because it may limit the surgeon’s exposure and puts squeeze on the gastrocsoleus muscle, preventing muscle mobilization.
The patient is turned into a prone position.
Chest rolls should be used if the patient is asleep for the procedure (this is usually not needed if the procedure is performed under spinal anesthesia).
Both lower extremities should be prepared and draped. This allows the unaffected side to be used as a template against which the resting tension of the repair can be assessed.
The legs should be prepared and draped to above the level of the knee joints.
FIG 2 • MRI shows a neglected Achilles tendon rupture. The white arrows indicate the proximal and distal stump ends, with a 5-cm gap.
TECHNIQUES
INCISION
After Esmarch exsanguination of the limb, the tourniquet is inflated and left inflated until a compressive dressing has been applied at the end of the procedure.
The approach to the repair involves an extensile incision over the posterior calf (TECH FIG 1A).
Place the distal incision, over the region of the rupture and gap, medial to the Achilles tendon.
This prevents injury to the sural nerve, which runs 5 mm lateral to the Achilles tendon, and keeps the incision away from the posterior aspect of the heel, where it could rub against a shoe counter, causing irritation.
This usually involves the most distal 10 cm of the incision.
Continue the incision sharply full thickness down to and through the paratenon. Reflect the paratenon off the tendon and preserve it for later repair.
Proximally, curve the incision centrally and continue it up the posterior midline of the calf up to the proximal extent of the myotendinous junction.
The sural nerve in the calf crosses from lateral to central over the myotendinous junction region and then passes under the medial head of the gastrocnemius muscle proximally.
The nerve must be identified (TECH FIG 1B) within the subcutaneous tissue, retracted, and protected throughout the rest of the procedure.
The nerve runs with the lesser saphenous vein, which aids in identifying its location, and the vein too should be preserved if possible.
Expose the entire tendon up to a level proximal to the myotendinous junction.
Carefully reflect the paratenon off the proximal tendon and preserve it for later repair.
TECH FIG 1 • A. The incision required to address a neglected Achilles rupture with a large gap between tendon ends. B. The sural nerve should be isolated as it traverses from the lateral aspect of the tendon distally to the posterior midline within the calf.
MEASUREMENT OF THE GAP
Once the ruptured region is identified, measure the gap. A scar pseudo-tendon is frequently identified within the rupture gap, and this should be resected together with the nonviable ends of the tendon.
Measure the true tendon gap (TECH FIG 2) with the knee flexed to 30 degrees and the ankle plantarflexed to 20 degrees to match the resting tension of the unaffected side.
TECH FIG 2 • The true tendon gap is measured with the ankle in neutral resting tension (compared to the unaffected side).
V-TO-Y LENGTHENING
Make an inverted-V incision through the tendinous portion only of the myotendinous junction of the GSA complex.
Leave the underlying muscle fibers intact and attached to the proximal muscle body.
Place the apex of the V in the midline at the most proximal portion of the myotendinous junction.
The limbs of the V then diverge to exit at the medial and lateral borders of the tendon, respectively. The V limbs should be at least one-and-a-half times longer than the length of the measured gap (TECH FIG 3A). In our experience with these more extensive gaps (greater than 5 cm), we recommend that the limbs of the V are at least twice the length of the rupture gap to allow adequate lengthening to be obtained.
Use a heavy braided nonabsorbable suture (we use no. 2 Fiberwire [Arthrex Inc., Naples, FL], but no. 5 Ethibond [Ethicon-J&J, Piscataway, NJ] can also be used) for the end-to-end tendon anastomosis after the lengthening.
Use a locking Krackow technique, placing at least five locking loops in a running style along the medial and lateral aspect of the tendon, on each end of the rupture (TECH FIG 3B).
Insert the suture into the free end of the tendon and then loop it in a locking pattern up the side of the tendon. Attempt to capture about one third to one half of the tendon width with each loop of the suture. Once five loops have been thrown, pass the suture through the substance of the tendon, exiting at the same level on the opposite side of the tendon. Throw another five locking loops toward the end of the tendon, with the suture exiting again at the free end of the tendon.
We have found that a single continuous suture is adequate for the repair.
Apply traction to the suture material within the proximal tendon stump in a distally directed longitudinal direction (TECH FIG 3C). This is a firm continuous traction, allowing the muscle fibers to gently stretch out and slide. A weight can be hung over the end of the table to facilitate traction. While some force is required to create this advancement slide, take patience and great care not to detach the tendon from the muscle, which would devascularize the tendon.
While this is being applied, gently tease the muscle fibers of the myotendinous junction longitudinally, allowing the myotendinous junction to slide distally.
Continue traction until the tendon ends can be approximated with the ankle resting tension matching the unaffected side.
Repair the V incision in the tendon, creating an inverted-Y configuration (TECH FIG 3D). The long arm of the inverted Y is the length that the tendon has been elongated—equal to the length of the measured gap.
TECH FIG 3 • A. The inverted V is made within the myotendinous zone. The limbs of the V are twice the length of the rupture gap. B. A locking Krackow-type stitch is placed in each end of the ruptured tendon, using at least five locking loops of braided no. 2 nonabsorbable suture. C. The inverted V is cut through the tendinous portion only, leaving the underlying muscle fibers intact. The underlying muscle fibers are allowed to slide after the V release is made in the tendinous portion. D. Once lengthened the V cut is repaired into a Y configuration.
FLEXOR HALLUCIS LONGUS AUGMENTATION
Before repairing the ends of the tendon together, harvest the FHL tendon and transfer it to augment the repair.
The FHL muscle lies in the deep posterior compartment of the leg immediately posterior to the Achilles tendon in this region. With the Achilles tendon and muscle belly reflected, the deep posterior compartment fascia can be incised and released, exposing the FHL muscle and tendon. The muscle of the FHL usually extends distally down to the level of the tibiotalar joint, making it easy to identify (it is frequently referred to as “beef at the heel”) (TECH FIG 4A). Identify the tendon at the distal end of the muscle and digitally retract it.
The hallux should be seen to flex on traction of the tendon, confirming that the correct tendon has been identified.
Immediately medial to the FHL muscle and tendon is the medial neurovascular bundle (including the tibial nerve and posterior tibial artery); take care to avoid injury to these structures.
Follow the FHL tendon around the medial malleolus (dissection should be performed along the lateral aspect of the tendon as the sheath is released behind the ankle to avoid inadvertent injury to the bundle) (TECH FIG 4B).
With the ankle and hallux held fully flexed and maximum traction placed on the FHL tendon, transect the tendon as distally as possible. In almost all cases, adequate length of tendon can be obtained using this technique (TECH FIG 4C).
Measure the tendon diameter (TECH FIG 4D); a corresponding-sized bone tunnel will be drilled into the posterior tubercle of the calcaneus directly anterior to the attachment of the distal stump of the Achilles tendon.
TECH FIG 4 • A. The flexor hallucis longus (FHL) muscle belly is seen distally deep to the tendon within the deep posterior compartment of the leg. B. The FHL tendon is retracted and followed to the level of the medial malleolus. C. The FHL tendon is transected at the medial malleolar level, leaving adequate tendon length for the transfer. D. The FHL tendon diameter is measured, allowing accurate tunnel sizing. E. A Beath pin is drilled through the calcaneus immediately anterior to the Achilles tendon insertion. F. The Beath pin is overdrilled with an appropriately sized cannulated drill bit so as to create the bone tunnel for the FHL tendon. G. The FHL tendon is pulled into the bone tunnel via the attached suture material and pulled to an appropriate tension.
Place a Krackow locking suture in the distal portion of the FHL tendon and pull the tendon into the bone tunnel. This is done using a Beath pin (long pin with a suture eyelet), pulling the suture ends out of the plantar aspect of the foot (TECH FIG 4E). Create the bone tunnel with a sizespecific cannulated drill bit over the Beath pin (TECH FIG 4F). Traction can be applied to the suture to hold the tendon within the bone tunnel at the appropriate tension.
Pull the tendon to the required tension before fixation. The ideal tension holds the ankle at a resting tension of the ankle equal to that of the contralateral side (TECH FIG 4G).
Fix the tendon into the bone tunnel using an interference screw of the same size as the bone tunnel. We use an absorbable biotenodesis screw (Arthrex) (TECH FIG 5).
TECH FIG 5 • A bioabsorbable interference screw (noncutting threads) is inserted into the bone tunnel holding the flexor hallucis longus tendon, obtaining interference fit between the tendon and the bone and completing the tendon transfer.
ALTERNATE TECHNIQUE FOR FLEXOR HALLUCIS LONGUS HARVEST
If additional length of the FHL tendon is required, the tendon can be harvested from the midfoot.
This requires a separate incision to be made over the medial side of the foot from the plantar aspect of the talonavicular joint extending to the midshaft of the first metatarsal.
Reflect the abductor hallucis and flexor hallucis brevis dorsally, exposing the long flexor tendons.
Identify the FHL and flexor digitorum longus (FDL) tendons at the master knot of Henry (beware of the medial plantar nerve!) and cut the FHL tendon.
The FHL stump can be tenodesed to the FDL tendon, but multiple communications exist between these two tendons and this is usually not necessary.
Retract the FHL through the posterior calf incision.
This technique allows the FHL tendon to be passed through a transverse bone tunnel in the posterior tuberosity of the calcaneus and looped back onto itself.
The double strands of tendon are theoretically stronger than a single strand, but no advantage has been shown clinically with this technique.
I prefer to use the first single-incision technique, limiting the risks of an additional incision and the risks to the structures dissected in the approach, including the medial plantar nerve and its branches.
ACHILLES TENDON REPAIR
After the FHL transfer is completed, attention is moved back to the Achilles tendon.
Oppose the proximal and distal ends of the tendon appropriately (via the V-Y slide) and tie them together with intratendinous knots, using the aforementioned nonabsorbable braided suture (TECH FIG 6A).
Once again, confirm that the ankle resting tension remains equal to the contralateral side to avoid overtightening of the repair (TECH FIG 6B).
Gently dorsiflex the ankle to ensure that no diastasis occurs between the tendon ends, confirming adequate integrity of the repair strength.
Suture the muscle belly of the FHL to the back of the Achilles tendon at the level of the repair with absorbable suture. This provides a vascular bed to the relatively disvascular level of the ruptured Achilles tendon, theoretically increasing the healing potential of the repair.
Repair the paratenon over the repaired Achilles tendon as a separate layer, using absorbable suture.
Close the skin in layers via routine closure.
Apply a well-padded posterior plaster splint with the ankle maintained at its resting level of plantarflexion (equal to the contralateral side), and release the tourniquet.
TECH FIG 6 • A. The ruptured Achilles tendon ends are approximated after the V-Y lengthening, allowing direct end-to-end repair of the tendon. B. The final resting tension of the repaired Achilles tendon is compared to and matched with that of the unaffected side.
POSTOPERATIVE CARE
Postoperatively patients are splinted for 2 weeks in slight equinus (equal to the resting tension of the unaffected side).
They are kept strictly non–weight-bearing for the first 6 postoperative weeks.
At 2 weeks after surgery incisions are checked and sutures removed.
Patients are placed into Achilles-type fracture boots (Bledsoe Inc., Grand Prairie, TX) with three heel wedges, and instructed to remove one wedge after 2 weeks.
After 6 weeks patients are allowed to start bearing weight on the affected extremity as comfort allows in their protective Achilles boot braces (with two wedges in place at this point).
Patients are then instructed to remove one wedge every 2 weeks thereafter.
Physical therapy is performed two or three times a week for the subsequent 10 weeks and includes passive Achilles stretching, an Achilles strengthening program, and gait training. This is performed with the boot brace removed.
Twelve weeks after surgery, if the ankle is in a neutral alignment, the boot brace is discontinued for ambulation, with the patient continuing the therapy program.
Patients are instructed to slowly resume their activity as comfort allows, but to avoid sudden acceleration and cutting or jumping activities until at least 6 months after surgery.
OUTCOMES
Outcomes of chronic or neglected Achilles tendon rupture repair are uniformly inferior to those of acute rupture repair.
Using a V-Y advancement alone, Us et al5 reported up to 22% deficiency in peak torque compared to the unaffected side in 6 patients.
Wapner et al6 reported on using the FHL tendon without VY advancement through a two-incision approach (with the second incision made in the medial longitudinal arch, where the FHL was harvested at the level of the master knot of Henry).
On Cybex testing they reported 29.5% average decrease in strength at 30°/s and decreases in torque and work generated by plantarflexion of the ankle as being 41.8% and 51% respectively compared to the nonoperated side.
In a recent study by Raikin et al4 using the combined V-Y lengthening and FHL augmentation described above on 15 patients with a minimum gap of 5 cm, a 7.7 N-m (−22.3%) loss of plantarflexion torque at 60°/s and a 3.5 N-m (−13.5%) loss of plantarflexion torque at 120°/s was seen on Cybex testing compared to the unaffected side.
Patients had an average 5-degree loss of active motion arc of the ankle joint in the sagittal plane. AOFAS ankle hindfoot scores improved from an average 58.4 out of 100 preoperatively to an average 94.1 out of 100 postoperatively.
Eight of 15 patients were able to perform more than 10 repetitions of a single-leg heel raise at 2-year follow-up.
All patients were satisfied with their outcome (rated good or very good).
COMPLICATIONS
Wound edge necrosis
Rerupture
Plantarflexion weakness
Sural neuritis or nerve injury
Deep vein thrombosis
REFERENCES
1. Jozsa L, Kvist M, Balint BJ. The role of recreational sport activity in Achilles tendon rupture: a clinical, pathoanatomical and sociological study of 292 cases. Am J Sports Med 1989;17:338–343.
2. Lagergren C, Lindholm A. Vascular distribution in the Achilles tendon; an angiographic and microangiographic study. Acta Chir Scand 1959;116:491–495.
3. Mandelbaum BR, Myerson MS, Forster R. Achilles tendon ruptures: a new technique of repair, early range of motion and functional rehabilitation. Am J Sports Med 1995;23:392–395.
4. Raikin SM, Elias I, Bessler MP, et al. Reconstruction of retracted Achilles tendon rupture with V-Y lengthening and FHL tendon. Foot Ankle Int 2007;28:1238–1248.
5. Us AK, Bilgin SS, Aydin T, et al. Repair of neglected Achilles tendon ruptures: procedures and functional results. Arch Orthop Trauma Surg 1997;116:408–411.
6. Wapner KL, Pavlock GS, Hecht PJ, et al. Repair of chronic Achilles tendon rupture with flexor hallucis longus tendon transfer. Foot Ankle Int 1993;14:443–449.