Lateral Ligament Repair of the Ankle

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Lateral Ligament Repair of the Ankle

Robert Donatelli, Will Hall, Brian E. Prell, Graham Linck and Richard D. Ferkel

The ankle requires both static and dynamic stability. Mobility is crucial for normal ankle function in the midst of rapidly changing postures of the foot during sporting and everyday weight-bearing activities. Lateral ligament injuries of the ankle account for 13% to 56% of all injuries in sports requiring running or jumping such as soccer, basketball, and volleyball.1,2 Ankle sprains also compromise 10% of the emergency room visits in the United States, with an incidence of 30,000 injuries per day.3 The large majority of these injuries can be successfully treated conservatively with casting, bracing, nonsteroidal antiinflammatory drugs, and physical therapy. Approximately 85% of all ankle sprains involve the lateral structures of the ankle.4,5 The majority of ankle sprains heal without any residual functional instability.4 Despite adequate trials of conservative measures, however, approximately 10% to 30% of all acute ligamentous injuries have recurrent symptoms of chronic pain, swelling, and instability with activities.4,69 Functional instability of the ankle is reported to be as high as 20% after ankle sprains.10,11 Ligamentous instability has been thought to be related to the loss of mechanoreceptors12 and can lead to the development of ankle joint degenerative changes.13 When conservative measures fail to produce satisfactory proprioceptive performance and mechanical stability, surgical repair or reconstruction of the injured lateral ligament structures should be considered.

Anatomy and Mechanism of Injury

The etiology of the unstable ankle is usually a forced plantar flexion inversion injury in which the body’s center of gravity rolls over the ankle. This type of force results in injury to the anterior talofibular (ATF) ligament; and possibly the calcaneofibular (CF) ligament, the anterior inferior tibiofibular ligament, or the posterior talofibular (PTF) ligament.3 The ATF ligament is the weakest of the lateral ligaments and blends with the ankle joint capsule. The CF ligament is the only extraarticular ligament among the complex and is larger and stronger than the ATF ligament14; it has been found able to withstand forces two to three-and-a-half times greater than that of the ATF ligament.15 The PTF ligament is the strongest of all the ligaments and is rarely injured with inversion sprains or associated with chronic ankle instability.14 The unstable ankle is generally caused by a traumatic event such as an ankle sprain. It also can be associated with ankle fractures but virtually never develops insidiously.

Surgical Indications and Considerations

A lateral ankle reconstruction is an elective surgery used to treat chronic instability that results from a continuum of ankle injuries. Ankle injuries can result in permanent damage to the ligaments that support the lateral ankle. Various studies have examined the benefits of surgical versus functional treatment in lateral ligament injuries of the ankle. These studies have shown that operative repair was associated with patients’ delayed return to work, restricted range of motion (ROM), impaired ankle mobility, and increased complications after surgery, including undefined pain.1619 This is in contrast to conservative treatment, which includes functional bracing and early mobilization. Kannus and Renstrom reviewed 12 prospective studies and found that functionally or conservatively managed patients with grade III ankle sprains returned to work two to four times faster than those patients who underwent acute repair of the damaged ligaments.20 Therefore, the surgical option is used when nonoperative treatments have failed, such as physical therapy, bracing, activity modification, and steroid injections. Postoperative physical therapy is a vital link in returning the patient to an active lifestyle.

Indications for reconstruction of the ankle’s lateral ligaments include recurrent giving way with activities of daily living (ADLs) and sports that is refractory to conservative treatment, a positive physical examination, abnormal inversion, and/or positive anterior drawer stress x-rays (Fig. 28-1).

Patients of all ages and types are candidates for this type of surgery, but few patients older than 50 years undergo ankle reconstruction because of decreased activity levels and an increased ability to adjust functions and lifestyle to avoid recurrent buckling episodes. Surgeons should take care when considering this procedure for patients with generalized ligamentous laxity and collagen disorders that may result in failure. In addition, advanced degenerative joint disease or arthrofibrosis may be relative contraindications to this surgery.

Surgical Procedures

More than 50 different surgical procedures for correction of lateral ankle instability have been described.21 The majority of reconstructive procedures use part, or all, of the peroneal brevis tendon. Common procedures include the Watson-Jones, Evans, Chrisman-Snook, and Elmslie procedures and their modifications. Anatomic repair with direct suturing of the torn ligaments, imprecation, reinsertion to the bone, and in some instances augmentation with local tissue have increased recently in popularity.10,22,23 Direct repair of the ATF and CF ligaments was described by Broström in 1966 and later modified by Gould in 1980.22,24 Direct repair of torn lateral ligaments has the advantage of being simple and reliable, avoiding the use of normal tendons. It restores the original anatomy, requires less exposure, and maintains full ankle motion.

Procedure—Modified Broström

The modified Broström procedure, also termed the Broström-Gould procedure, is the method of choice for most patients with lateral ankle instability. The patient is taken to the operating room and examined under anesthesia. If the surgeon has any questions about the degree of ankle instability, stress x-ray films (stressing the ankle in both inversion and anterior drawer) are taken. The thigh is then secured on a well-padded thigh holder in preparation for ankle arthroscopy, as described in Chapter 30. The lower extremity is prepared and draped in standard fashion. Arthroscopy is performed first; the authors of this chapter have found that 93% of patients have additional intraarticular ankle pathology associated with lateral ankle instability in one study.5 More recently, in another study, we found 95% of patients had associated intraarticular problems noted at arthroscopy before the Broström procedure.25 In addition, a similar report by Taga showed 95% of patients have additional intraarticular pathology at the time of ankle reconstruction.26 Hua and associates27 found 91% of patients to have intraarticular lesions at the time of the modified Broström reconstruction.

The intraarticular pathology is identified and addressed through arthroscopic surgery. The scarred anterior talofibular (ATF) ligament is identified and assessed to make sure it is adequate for the modified Broström repair. After the arthroscopy is completed, the nurse removes the thigh support and places the leg flat on the surgical table. The ankle is reswabbed with a sterile antibacterial solution. An additional clean surgical drape is placed over the foot and ankle, and gloves are changed. New sterile instruments are used to perform the open portion of the procedure. Arthroscopic methods are now available for surgical reconstruction of the lateral ankle ligaments, but at this time open stabilization as described by Broström gives a better, more reproducible result. Recently, Corte-Real and Moreira,11 Lui,28 Nery and associates29 reported on their arthroscopic method for chronic lateral ankle instability. The results had a high percentage of good-excellent results, but long-term studies are necessary to compare the arthroscopic with the open procedures before a recommendation can be made for switching to all-arthroscopic techniques.

After arthroscopy the ankle is prepared and the tourniquet inflated. An incision is made over the lateral aspect of the ankle. This incision may be obliquely shaped in the skin folds or more vertical from the fibula toward the sinus tarsi, depending on the surgeon’s preference and the clinical situation. The senior author prefers the vertical incision because it allows better assessment of the peroneal tendons and can be extended distally and proximally if other procedures need to be done. Dissection is carried down through the subcutaneous tissues and the extensor retinaculum is carefully exposed because it is to be used for later reattachment. The surgeon must take care to avoid the intermediate dorsal cutaneous nerve, the lateral branch of the superficial peroneal nerve (which often lies near the end of the ATF ligament), and the sural nerve (which lies over the peroneal tendons). An oblique capsular incision is then made along the anterior border of the fibula from the AITF ligament to the CF ligament, leaving a small 3- or 4-mm cuff of tissue on the fibula for reattachment of the torn ligament complex (Fig. 28-2). The stretched ATF ligament is found as a thickening in the anterior capsule, and the CF ligament is found in the distal portion of the wound under the tip of the fibula, running deep to the peroneal tendons. The CF ligament often is attenuated or avulsed from the fibular tip.

A “pants-over-vest” overlapping suture technique is used to imprecate or shorten the torn ligaments and provide a double layer of reinforcement to the repair. Suturing is done starting from the ligament portion attached to the talus, so that the knots are tied distal and inferior to the fibula (Fig. 28-3). This helps prevent postoperative knot prominence and skin irritation with shoe wear. “O” nonabsorbable sutures are used in the majority of the repair, but one absorbable suture is used for the CF ligament near the peroneal tendon, to avoid irritation. The sutures are tied with the ankle in neutral position, and a posterior drawer is applied to reduce the talus. The ankle is checked to make sure full ROM has been maintained during the repair. The extensor retinaculum is then pulled proximal over the repair and sutured to the fibular periosteum. ROM is again checked, as is the stability of the ankle. The tourniquet is released, and bleeding tissues are coagulated. The subcutaneous tissue and skin are then closed in the standard fashion. The patient is placed in a short-leg well-padded cast that is split in the recovery room to allow for swelling.

The patient’s cast is changed at 1 and 2 weeks and the stitches are removed. Weight bearing is started at week 3 in a cast or cast boot, at the surgeon’s discretion. Physical therapy with mobilization starts usually at week 6 or sometimes sooner.

Procedure—Anatomic Hamstring Reconstruction

Indications for an anatomic hamstring reconstruction include a high-stress, heavy athlete, generalized ligamentous laxity, deficient ATF ligament tissue for direct repair, talar tilt greater than 10o more than the opposite ankle, and a varus hindfoot. The incision used is the same as shown in Fig. 28-2, A. The lateral ligaments are released in the same oblique fashion for later reattachment over the hamstring repair. An autogenous or allograft semitendinosus graft is prepared with nonabsorbable sutures at both ends. A guidepin is inserted into the fibula to create two converging bony tunnels, beginning from insertion of the ATF ligament on the fibula, as well as the insertion of the CF ligament on the fibula. These tunnels are connected using a curved curette. Alternatively, as option B, the holes can be drilled out the posterior fibula to increase the bone bridge between the anterior talofibular ligament (ATFL) arm and the calcaneofibular ligament (CFL) arm. A reamer is then placed over the guidepin to create 5-mm tunnels. A guidepin is then inserted along the talar neck at the nonarticular portion and reamed to a predetermined size based on the diameter of the graft (Figs. 28-4 and 28-5). A passing device is placed from posterior to anterior through the fibula to facilitate graft passage (Fig. 28-6). The graft is then fixated on the talus with a special interference screw that helps push the tendon into the bone socket (Fig. 28-7). Alternatively, in option B, the graft can be passed from anterior to posterior and the ATF arm can be separately tensioned and fixed with an interference screw before tensioning the CFL arm (Fig. 28-8). This is usually done in slight plantar flexion because this is when the ATF ligament is the tightest. The tensioning on the CFL arm is done in slight dorsiflexion, and the tendon is passed underneath the peroneal tendons to exit into a drill hole made through the calcaneus. The CFL arm is cut so that 20 mm of the tendon will be in the calcaneus when it is secured with an interference screw (Fig. 28-9). This is done with the ankle in neutral position by bringing the sutures out through a poke hole on the medial heel and pulling tension on the sutures while the screw is inserted in the calcaneus (while pulling the graft into the tunnel) (Fig. 28-10). The final constructs gives anatomic reconstruction of the ATFL and CFL (Fig. 28-11). A modified Broström repair is then done over the hamstring reconstruction.

The patient is then placed in a cast which is split in the recovery room. The cast is changed at 1 and 2 weeks, and the stitches removed. Weight bearing is started at week 3 in a cast or a cast-boot at the surgeon’s discretion. Physical therapy usually starts in the pool at week 6 or 8, depending on what else is done at surgery.

Surgical Outcomes

A lateral ankle reconstruction is considered to be successful when the patient has full ROM and a pain-free ankle and can return to all ADLs and sports without restriction. Liu and Baker30 studied the static restraints of various surgical procedures in 40 cadaveric ankles. They found no significant difference between the Watson-Jones and Chrisman-Snook procedures, but the modified Broström procedure produced the least anteroposterior displacement and talar tilt at all different forces tested.

Hennrikus31 prospectively compared the Chrisman-Snook and modified Broström procedures in 40 patients. Although both produced 80% good-to-excellent results, the former procedure had a much greater proportion of complications and the latter procedure had a higher functional score. Hamilton et al34 performed the modified Broström procedure on 28 ankles; 54% of the patients were high-level ballet dancers. At 64 months’ follow-up, he noted 27 of 28 good-to-excellent results. Peters33 reviewed the literature and found 460 ankles treated with anatomic modified Broström repairs had an average of between 87% and 95% good-to-excellent results.

Ferkel and Chams25 reviewed the results of 21 patients who underwent the modified Broström procedure. The average patient age was 27.5 years and the average follow-up occurred at 57 months. They found 95% good-to-excellent results with an American Orthopaedic Foot and Ankle Society’s (AOFAS) ankle/hindfoot score of 97.1. When the ATF ligament is not adequate to use for a Broström repair, we use either an autogenous or allograft hamstring graft with biotenodesis screws through the talus and calcaneus to reconstruct the ATFL and CFL.3436

Alternatively, the Broström-Evans procedure can be used in patients with the same indications as the hamstring reconstruction. In this procedure, the peroneal brevis is split using one third of it through a drill hole in the tip of the fibula, exiting the posterior fibula. The peroneal tendon is then secured with an interference screw and the Broström is placed over it. Results with the Broström-Evans procedure have also been good.22

Challenges

Despite having a stable ankle postoperatively, some patients still complain of pain, aching, swelling, and crepitation.26 Many of these complaints may be related to preexisting intraarticular pathology such as degenerative joint disease, osteochondral lesions of the talus, loose bodies, chronic synovitis, and chronic scarring. Occasionally the ankle can be made too tight at the time of reconstruction; this severely limits the patient’s ability to invert. This is the single most serious complication after ankle reconstruction. If a patient does not have full motion after surgery, especially full inversion and eversion, rehabilitation is significantly compromised and the patient tends to develop a painful valgus hindfoot.

Precautions and Contraindications

The physical therapist should increase the level of rehabilitation gradually for the patient after surgery. Too-vigorous exercise and the use of isokinetic machines can lead to increased pain, shear stress, and swelling that can last for weeks to months and stretch the reconstruction. If this occurs, the ultimate results can be compromised and the patient, physician, and physical therapist can all become quite frustrated. Every patient progresses at a different rate and the exercise program should be customized to the individual needs of each patient.

Rehabilitation Concerns

The therapist should contact the physician whenever pain appears to be out of proportion to expectations. In addition, any wound drainage, evidence of fever or infection, and increased laxity should alert the therapist to interact with the surgeon. If the patient has an acute episode of pain or feels a “pop” or significant change during rehabilitation or ADLs, the surgeon should be alerted immediately.

Therapy Guidelines for Rehabilitation

The first 6 weeks after surgery are important for the succes of the surgery. Whether the reconstruction was done with primary ligamentous repair (as in the Broström procedure), with tendon augmentation (as in the Chrisman-Snook procedure), or with hamstring reconstruction, the initial tissue healing stage is important.9,31 The surgical reconstruction to correct the ligamentous instability is only as good as the stability gained from soft tissue healing. Soft tissue healing is considered the maximal protection stage.

Evaluation

The initial postoperative evaluation gives the therapist a baseline from which to proceed in returning the patient to desired independent function. Initial ROM measurements are taken both for active range of motion (AROM) and passive range of motion (PROM). PROM is measured within a pain-free range, especially while measuring forefoot inversion.

imageThe physical therapist has a responsibility to the surgeon and the patient to protect the lateral ligamentous reconstruction. Forefoot inversion stresses the reconstructed tissues and must be carefully engaged. Manual muscle testing to determine strength of the lower extremity can be part of the initial evaluation. However, muscle testing at the ankle is delayed until the patient has progressed and accommodated to resisted exercises at the ankle. imageThe therapist should avoid having the patient perform a single–leg heel raise, which is usually advocated to determine normal gastrocnemius-soleus strength, because of decreased proprioception and the significant muscle deficits resulting from the effects of immobilization. The incision is assessed for mobility and hypersensitivity after complete healing has occurred. Operative damage to the sural nerve and the lateral branch of the superficial peroneal nerve has been reported as a cause of decreased sensation in the involved ankle.10,37 Joint effusion and soft tissue edema can be factors in limited ROM, proprioception deficits, and the inability to strengthen the joint. Joint and soft tissue mobility also are assessed at the limits of ROM.

Phase I

TIME: Weeks 4 to 6 after surgery

GOALS: Decrease pain and swelling, restore joint and soft tissue mobility, increase strength in lower extremity and ankle, increase proprioception, normalize gait, maintain cardiovascular fitness, and provide patient education (Table 28-1)

TABLE 28-1

Lateral Ligament Repair

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Rehabilitation Phase Criteria to Progress to This Phase Anticipated Impairments and Functional Limitations Intervention Goal Rationale
Phase I
Postoperative 4-6 weeks