Tendinopathies of the ankle joint

TENDINOPATHIES OF THE ANKLE JOINT

ANDREA SCALA, MD, MASSIMO CIPOLLA, MD, and VITTORIO FRANCO, MD

Tendons around the ankle joint may undergo overuse pathology. The anatomy of the ankle must be thoroughly studied in order to understand the causes of the overuse pathology, and their clinical presentation. Changes in tendon functioning may arise following biomechanical alterations of the foot and ankle. Anatomic repair of the tendon tear-and-wear injuries is mandatory, as well as reconstruction of completely disrupted tendons. Restoration of the biomechanics of the foot and the ankle contributes to improved repair procedures and greatly helps in preventing recurrences of tendon disease. KEY WORDS: ankle joint, tendon overuse, surgery

The tendons that surround the ankle joint are enclosed in sheaths lined with a synovial membrane. Tendons and sheaths are bounded down by fibrous bands, imbedded in or fused with the external investing layer of deep fascia. These bands occupy position proximal and distal to the ankle and are divisible into three groups: (1) the retinacula for the extensor muscle, superior and inferior; (2) the retinaculum for the flexor muscles; and (3) the retinacula for the peroneal muscle, superior and inferior? The tendons of medial, anterior, and lateral aspect of the ankle are divided in compartments by fibrous bands. Osteofibrous tunnels represent the passage of tendons and sheaths close to bony structures. Fibrous tunnels are constituted by the duplication in two layers of the upper band of the inferior retinaculum. Compressive forces exerted at this site may jeopardize the 'vessels of the mesotendon contained in the synovial sheath and induce areas of critical hypovascular- itty within the tendons. Spontaneous disease or rupture of a tendon around the ankle rarely occur in absence of predisposing factors that impair the tendon intrinsic structure. The tendon belly may become inflamed, degenerated, and disrupted following overuse injuries, attrition and meta- bolic diseases. Inflammation, scarring, longitudinal splits, partial rupture, and complete ruptures may make it diffi- cult for tendons and sheaths to slide underneath fibrous fasciae, retinacula, septa, and ligaments. Constrictive and attritional pathology may occur under these circum- stances. Triggering of the involved tendons and painful limited range of motion may be the main symptoms. Primitive or acquired malalignments of the tarsal bone and joints may induce perturbation in biomechanical functioning of the foot and ankle and lay the groundwork for the diseases and injuries of the talocrural joint tendons. A review of the surgical treatments reported in the orthopae- dic literature for the tendon diseases and injuries around the ankle is presented.

From the Ciinica Valle Giulia, Rome, Italy. Address reprint requests to Andrea Scala, MD, Clinica Valle Giulia, via

Giuseppe De Notaris, 2/B, 00197 Rome, Italy. Copyright © 1997 by W.B. Saunders Company 1060-1872/97/0503-000955.00/0

E X T E N S O R H A L L U C I S L O N G U S T E N D O N P A T H O L O G Y A N D S U R G I C A L T R E A T M E N T

The tendon sheath for the Extensor Hallucis Longus (EHL) reaches proximally to just above the level of the tips of the malleoli and is prolonged on to the base of the first metatarsal bone. Acute rupture of the EHL tendon is an extremely rare injury. Rupture occurring in the tendinous portion, at level of the first metatarsophalangeal joint, 2 at the musculotendinous joint, and at the level of the extensor retinaculum s have been reported. Attrition due to a dorsal bunion, surgery trauma subsequent a cheilectomy, and effects of steroid injection have been considered among the predisposing factors of the rupture occurring at the distal portion of EHL. The avascular segment of the tendon due to an injuried mesotendon is the designed site of rupture.

Surgical Procedure for Distal EHL Tendon Rupture

The surgical procedure used in case of distal rupture is a primary repair. The ends of the torn EHL were reapproxi- mated with a nonabsorbable 2-0 suture using the Bunnel suture technique without undue tension. The edges of the repair were reinforced with a running 4-0 absorbable suture. After surgery a short leg walking cast was performed with extended toes. After 2 weeks, gentle passive extension exercises were allowed by removing the area of the dorsum of the toes. A wooden-soled shoe was used in the subsequent 2 to 3 weeks to facilitate progression to regular shoes. The subsequent 2 to 3 weeks are needed to facilitate progression to regular shoes. The examination after 6 months follow-up demonstrated full extension strength of the great toe. The range of motion was pain free, although limited to 20 ° of flexion and 20 ° of extension. 2

Surgical Procedure for Proximal EHL Tendon Rupture

Repetitive microtrauma and hypovascularity is the sup- posed etiology of the EHL tendon rupture occurring at the level of the extensor retinaculum. 3 The clinical presentation was a flexion deformity at the interphalangeal joint of the hallux and the impossibility of active extension of the great toe. Surgical exploration of the ankle joint was performed

Operative Techniques in Sports Medicine, Vol 5, No 3 (July), 1997: pp 157-169 1 5 7

because of the history of swelling and pain at this level. After the cutaneous incision a 5 cm defect in the EHL was found, extending from a point 1 cm proximal to the superior band of the inferior extensor retinaculum to a point 2 cm distal to the retinaculum. After the excision of the fibrous tissue in the tendon defect a primary tendon repair was performed with 2-0 Prolene suture. A below-the- knee cast and toe platform was worn for 6 weeks in order to protect the repair.

ANTERIOR TIBIALIS PATHOLOGY AND SURGICAL TREATMENT

The Anterior Tibialis Tendon (ATT) passes through the most medial compartments of the extensor retinacula and distally inserts into the medial and plantar surface of the first cuneiform bone and the base of the first metatarsal bone.

The injuries that affect the ATT during sports activities are paratenonitis and paratenonitis with tendinosis. Jump- ers usually develop paratenonitis with an acute onset during an intense performance. Extension and flexion of the foot are causes of acute pain. Crepitation may be palpable on the anteromedial aspect of the ankle. Swelling of the tendon and sheath is a preeminent sign. The Extensor Hallucis Longus may be involved. Long distance runners and walkers may be affected by a chronic form of paratenonitis with tendinosis characterized by a painful feeling of attrition along the anterior compartment of the leg.

Surgical Procedures for the ATT Paratenonitis

Surgical treatment is reserved almost exclusively to chronic forms. Release of the sheath, tendon exploration for nod- ules and debridement are performed. Fasciotomy of the anterior compartment of the leg is associated in order to remove constrictions of the muscle and tendon blood supply. Ruptures of the ATT are extremely rare during young age and sports-related activities. The mechanism of rupture is a forceful plantarflexion of the foot. The patient refers pain on the anterior aspect of the ankle followed by appearance of drop-foot and painless, flat-footed gait. Objectively it results in the patient not being able to walk on the heels. The foot is everted in standing position, and the medial arch is lowered. A visible and palpable defect is observed in the tendon just distal to the transverse retinacular ligament. Avulsion fracture at the tendon's insertion on the navicular bone has been reported. 4 Degeneration of the tendon generally precedes the rupture. 5 The Anterior Tibial muscle and tendon unit derives all its blood supply from the anterior tibial artery. Constrictive obstacles to the vessels linked to sports may lead to impairment of tendon integrity and to its degeneration.

Surgical Procedure for ATT Rupture

Repair of ATT ruptures is mandatory in active patients regardless of age. An end-to-end repair with a Kessler-type stitch of I nonabsorbable suture is performed. The periph- ery of the tendon is subsequently sutured with a running absorbable 3-0 suture. In case the tendons ends cannot be brought together a reconstruction procedure using the

tendon of the EHL as a graft has been described. 6 A plaster cast splint immobilizes the ankle for 3 weeks in a neutral position. A removable splint is then used to allow active range of motion exercise. After 6 weeks from surgery immobilization is discontinued and stretching exercises are initiated. Full function is resumed within 12 to 14 weeks from surgery.

POSTERIOR TIBIALIS TENDON PATHOLOGY AND SURGICAL TREATMENT

The Posterior Tibial Tendon (PTT) is a foot invertor and maintains the medial arch height during the stance phase. In sport active population overuse injuries are generally responsible for the onset of PTT tenosynovitis.

Predisposing factors must be considered: (1) the pro- nated foot; (2) the subtalar joint instability in a cavus valgus foot; and (3) accessory navicular.

(1) Athletes with a varus forefoot or apes planus with an everted rearfoot are bound to an excessive pronation. The distal tibia vara is a predisposing factor that acts in a similar way. In order to allow the medial aspect of the foot to come into contact with the ground during stance, the foot is forced to pronation. The tendon contracts chronically to prevent the medial arch collapse.

(2) The cavus valgus foot is featured by the valgus rearfoot and medial dislocation of the tarsal bones. The proper flexibility of talonavicular and calcaneocuboid joint turns to an exaggerated oscillation. The subsequent subtalar joint instability leads to posterior tibial tendinitis.

(3) Following to chronic solicitation or an acute sprain the accessory navicular junction may fracture. The posterior tibial tendon is involved in the abnormal motion that is determined.

Surgical Procedures for PTT Insufficiency

When chronically exposed to the aforementioned factors the PTT becomes insufficient to exert dynamic control on the medial longitudinal arch. Insufficiency of PTT due to tenosynovitis or attenuation may arise. Johnson 7 defined this condition dysfunction of PTT, described the stages of the tendon pathology, and formulated a plan of treatment. PTT dysfunction is a condition not rarely found that affects the structure of the medial side of the foot as well the tendon.

In Stage I tenderness along the course of the tendon and the medial aspect of the ankle is shown on physical examination (Fig 1) Pain and diminished inversion power are present. The tendon is normal in lenght but there is peritendinitis or tendon degeneration and minimal secondary deformity. 8 In case of Stage I PTT dysfunction, the recommended procedure is described as follows: After the surgical incision the flexor retinaculum is identified and opened. The tendon sheath is opened from the musculotendinous junction all the way to its insertion, leaving a 1-cm pulley posteriorly to the medial malleolus. Tendon synovec- tomy and tendon debridement are then performed. Small flap tears, when assessed, must be debrided and larger tears sutured. When the tendon is enlarged to more than 1.5 mm the normal size a wedge is removed from the substance to debulk the tendon (Fig 2) and the remaining

158 SCALA ET AL

Fig 1, Picture of an enlarged Posterior Tibial Tendon in a young sprinter.

longitudinal gap must be carefully sutured. The retinaculum is not resutured.

A walking below-the-knee plaster cast is held for 3 weeks. After removal of sutures a weightbearing cast is held for 3 weeks. Following this period a rehabilitation program is started whose important steps are the regaining of strength and endurance of plantar-flexion and inversion. Sports activities are not authorized until a full, painless range of motion of the ankle and foot articulations and equal strength of the tibialis posterior muscle tendon unit are present. 9 In Stage II the tendon is ruptured and secondary changes develop. The patient is unable to perform single limb-heel-rise test, which indicates weakness of the PTT. The too-many-toes sign is positive, which indicates the insurgence of secondary deformity. In Stage III the tendon is disrupted and the foot is structured in a rigid deformity.

Surgical Procedure for PTT Insufficiency With Acces- sory Navicular

The accessory navicular is usually unperceived. Symptoms become evident following a vigorous sprain on the medial side of the foot and ankle. The involvement of PTT is

Fig 2. The enlarged portion of the PTT is removed to debulk the tendon,

frequently missed. Persistent pain on the medial side of the foot, initial collapse of the medial arch, impairment of the athletic activities allow the correct diagnosis. This may occur with a delay that ranges from several months to 2 years.

The appropriate treatment consists of excision of the accessory navicular after careful dissection of PTT. The continuity of the tibial tendon must be accurately re- spected, especially the fibers bounded to the plantar side of the navicular and metatarsals. After the excision, the navicular is regularized to a smooth surface, especially when a cornuate bone is present. The posterior tibial tendon is anchored to the bone, to prevent any loss of tension. The PTT tendon belly is anchored passing the sutures through Ere-drilled tunnel into navicular bone. In younger patients this procedure is performed without relevant risk. In older patients, the procedure may induce an impairment of the vascularity of the tendon.

Surgical Procedure for Acute Traumatic Dislocations of PTT

Acute disruptions of PTT occur rarely as a consequence of medial malleolar fractures. 1° Acute traumatic dislocation of PTT is a rare injury. The PTT tendon is dislocated anteriorly. After the repositioning of the PTT the surgical reconstruction of the torn flexor retinaculum was performed by using bone-in-through sutures. After repair no immobilization was prescribed. No weight bearing was allowed for 6 weeks. After rehabilitation, full sports activity was resumed within 10 weeks. 11

Another technique of repair is the reconstruction of the flexor retinaculum with a medial slip of the Achilles tendon that is detached proximally and attached to the medial malleolus. A full functional recovery is obtained within 12 weeks. 12

Acute dislocation of the PTT tendon may be associated to a fracture of the lateral malleolus. The injury is considered by some as an equivalent of bimalleolar fracture. A retinacular repair was performedJ 3

Surgical Procedure for Chronic Dislocation of PTT

Chronic dislocation of PTT is a rare event. It has outlined the necessity not only to reconstruct the flexor retinaculum but to deepen the groove around the medial malleolusJ 4

Surgical Procedure for Dysfunction and Rupture of PTT

Posterior tibial tendon rupture in athletes is an event of particular gravity because it may hamper running and jumping. Athletes who experience this disease are usually in their maturity. PTT disruption is evident in the latest stage of tendon dysfunction. 7

PTT rupture has been postulated to occur as a result of degenerative changes to the tendon. Tenosynovitis, constrictive bands beneath the flexor retinaculum, trauma, rheuma- tologic, and dismetabolic conditions are indicated as causes.

The lack of proximity of major trauma suggest that rupture of their posterior PTT was more likely related to an intrinsic abnormality, or biomechanical failure, rather than an extrinsic traumatic factor. The relatively younger pa-

TENDINOPATHIES OF THE ANKLE JOINT 159

tients are exceptions to this rule. Remote prior trauma or surgery are not infrequent in younger patients. A history of previous trauma or surgery in the younger patients is of most importance. Although a thrust on the medial side of the foot could be the initiating moment of a degenerative process of the PTT in a predisposed foot, the diagnosis is often missed. As ankle sprains is a misleading diagnosis, PTT dysfunction remains unrecognized until severe signs and symptoms become evident. Corticosteroid injection has been shown to induce local microvascular attenuation in the tendon. The effects of corticosteroid may further be associated with local vascular impairment and eventual rupture of PTT. 15

Among the younger group of athletes particular condition of the foot like a cavus valgus foot may induce a PTT dysfunction and eventually to a painful pes planus. The rupture occurs when those factors are not diagnosed and the necessary treatments have been delayed or not under- taken. After the rupture of the PTT tenderness along the course of the tendon and unilateral painful pes planus are shown on physical examination (Fig 3 A, B.) In patients with bilateral pes planus worsening of the affected side is evident.

The medial arch lowers under the body weight and progressive medial protrusion of the talar head intervenes. Changes that characterize the posterior tibial rupture specifically involve the structures that surround the talo- navicular joint. The spring ligament that sustains the talar head, the fibrous medial wall of the talo-navicular joint, the talar aspect of the navicular and the anterior medial facets of the calcaneus for the talar head are the components of this ball-and-socket joint. The PTT as inserting beneath the navicular suspends dynamically this "key stone" of the medial arch'~ When the PTT becomes insufficient the talar head turns medially, subtalar joint malalignment occurs .and the calcaneus everts as a consequence (Fig 4 A, B). If the valgus orientation of the calcaneus, the talar head plantarflexion, the abduction of the forefoot and the forefoot varus-supination deformity remain uncorrected, the foot evolves toward a rigid painful pes planus. The too-many-toes sign becomes evident. The medial arch comes in contact with the ground. Surgical procedures are performed with the goal to restore the normal connection among the tarsal bones and joints. The medial protrusion of the talar head and the heel valgus must be corrected in order to reduce the subtalar subluxation. A prerequisite is that all patients considered for soft tissue reconstruction must have a flexible subtalar joint.

The normal prono-supination motion is the consequence of the realignment of the subtalar joint.

Surgical Procedures for Partial Tear

The PTT attenuation is manifested by the incapacity to invert the hindfoot while tip-toe standing. Swelling and tenderness are usually present with valgus of the rearfoot. The recommended technique of partial tears is (1) release of the flexor retinaculus, (2) excision and resuture of the tendon, and (3) augmentation of hindfoot inversion power by the Flexor Digitorum Longus (FDL) transfer. 9

After the surgical incision the flexor retinaculum is

B

Fig 3. (A) Picture of tenosynovitis of PTT. The swelling of the medial side of the foot is evident. (B) Photopodogram of the same patient, assessing the contact with the ground of the collapsed medial arch.

severed. The distal end of the PTT shows a bulbous appearance. The remaining portion of the PPT that lies underneath the flexor retinaculum appears flattened. The dissection is directed plantar-ward until the FDL is identified. The tendon is distally severed and as much length as possible is maintained. A tunnel is then gradually drilled until a 4.5 mm width is reached. The distal end of the FDL is rerouted from the dorsal to the plantar aspect of the navicular. The foot is placed in a equinovarus position and the FDL is sutured onto itself. The PTT is sutured end-to- end with the proximal FDL muscle-tendon junction.

After the procedure a below-the-knee cast is performed and held for 3 weeks saving the varus-equinus position. After this period the cast is changed weekly until square- angle position of the ankle is regained. Cast immobilization is held also during the initial phases of the rehabilitation program. Advised total casting time is 14 to 16 weeks. 9

The surgical procedure described by Jahss in Stage I of Tibialis Posterior degeneration is the proximal and distal

160 SCALA ET AL

Fig 4. (A) The radiograph shows the medial protrusion of the talar head in a case of severe dysfunction of the PTT on a dorsoplantar view. (B) MRI that assesses the severe intramu- ral degeneration of the PTT.

anastomosis to the flexor digitorum longus (Fig 5). 16 This procedure is credited to retain the motor function of the PTT as an invertor and a stabilizer of the hind foot. It is not appropriate to sacrifice, for either grafting or repair, any invertor such as the flexor digitorum longus or flexor hallucis longus. If the tibialis posterior is too attenuated, augmentation with free extension digitorum longus grafts is advised. When the peritalar subluxation becomes evident, triple arthrodesis is indicated.

Surgical Procedures for Complete PTT Rupture

Several recent studies have indicated failures of tendon transfer used for the surgical reconstruction of complete PTT ruptures. The determination of a failed reconstruction is defined 17 on the base of the recurrence of severe symptoms on the medial side of the ankle, including pain, swelling, and tenderness. Progression of hindfoot deformity in association with decrease in inversion strength was also considered to indicate failure of the surgery. Magnetic resonance imaging (MRI) has been considered of great use as diagnostic tool for the PTT dysfunction staging and of a predictive value for surgical outcome. The patient with MRI type II and III ruptures may have a greater risk of failure. The disadvantage of this procedure is the potential consequence of subjecting the flexor digitorum longus tendon to the same biomechanical, anatomic, and environ- mental condition that caused the degeneration of the PTT. An indirect confirm of this consideration is the report of a rupture of a flexor digitorum longus transferred as a reconstruction procedure in case of PTT rupture. 18 Because no specific technical errors could be identified to explain the tendon rerupture, one reason for the failure may have been the unrestrained subluxation of the subtalar joint and plantarflexion of the talus.

Failures of the reconstruction techniques performed exclusively on the medial side of the foot are destined to failure and recurrence because of the persistent condition of subtalar joint instability and malalignment. Lateral column procedures achieve the correction of subtalar joint pathomechanics thus preventing further ruptures.

Surgical Procedure for Tendon Transfer Combined With Displaced Osteotomy of the Calcaneus

The drawbacks of the flexor digitorum longus transfer reduce dramatically if the medial displacement osteotomy of the calcaneus is associated with the transfer.

The osteotomy realigns the valgus heel under the mechanical axis of the leg and reduces the deforming valgus moment of the gastrocnemius-soleus muscle group. The flexor digitorum longus transfer is thus delivered from the antagonistic forces that lead to the insufficiency and rerupture. I9

The lateral aspect of the calcaneus is exposed through a slightly curved incision. The osteotomy line is inclined posteriorly of 45 ° to the plantar surface of the hindfoot while the direction of the oscillating blame is perpendicu- lar to the lateral wall of the calcaneus. Care must be taken to not penetrate the posterior facet of subtalar joint. No bone wedge is removed and no varus tilt is attempted. The two bone fragments are separated and the posterior tuberosity of the calcaneus is medially translated 10 mm. Proximal sliding of the posterior calcaneal tuberosity must be avoided. The osteotomy is fixed by means of a calcellous lag screw. The screw is inserted from posterior, lateral, and inferior to anterior, medial and superior.

On the medial side of the foot the procedures usually performed are (1) tendon advancement or (2) side-to-side tenodesis with the FDL. In case of advanced dysfunction of PTT, the distal tendon of the FDL is exposed. A bone tunnel is drilled through the navicular. The FDL is rerouted in the


tunnel from the plantar to the dorsal side of the navicular. The capsule of the talo-navicular joint is tensioned either by excision of an elliptical portion or plicated in a vest-over- pants fashion. Before the suture of the tendon reconstruction the right tension is obtained by mantaining the foot in maximum inversion and slight plantarflexion.

Lengthening of the Lateral Column of the Foot for the Insufficiency of the PTT and Planovalgus Deformity

Severe degeneration of the PTT is accompanied by planovalgus often complicated with a painful accessory navicular? The medial protrusion of the talus and the abduction of the forefoot are also features of this condition.

In order to reduce the lateral dislocation of the talo- navicular and calcaneo-cuboid joints lengthening of the lateral column of the foot are performed.

The medial side of the foot undergoes the described procedure to reconstruct the degenerated PTT or to excise the accessory navicular. On the lateral side of the foot the skin incision follows the axis of the fourth intermetatarsal space. The lateral aspect of the calcaneus is prepared carefully by dissecting all the surrounding structures. The osteotomy is performed 1 to 1.2 cm proximal to the calcaneo-cuboid joint. The osteotomy is preceded by drilling several holes oriented slightly distally 10 ° to 15 ° in order to prevent damages to the anterior part of the subtalar joint. The osteotomy is completed by means of an osteotome. Medial displacement must be avoided while the two fragments of the calcaneus are gently separated by a lamina spreader. The gap is filled with a tricortical bone graft previously harvested from the iliac crest. Both the osteotomy and the iliac graft are fixed with Kirschner wires. The PTT repair after accessory navicular excision or the necessar)~ reconstruction following the aforementioned procedures are then performed. The immobilization period and the rehabilitation program are the same used for the operation performed for the reconstruction of the PTT. After the operation on a weightbearing radiograph the talo-navicular coverage angle 2° is measured. This measure allows a direct evaluation of the obtained correction.

Arthroeresis for the Treatment of PTT Dysfunction in Young Patients

Young athletes with a cavus valgus foot may be predisposed to the development of a PTT dysfunction. In these patients the hindfoot is everted, the talar head is medially displaced, and the tibio-talar joint is internally rotated. The peculiar feature of this condition is the apparently mantained height of the medial arch despite the appearance of a pes planus while the lateral profile of the foot shows a "break" at calcaneo-cuboid joint due to the valgus hindfoot and the forefoot abduction (Fig 6 A, B, C, D).

The eversion of the subtalar joint and the heel valgus are mantained by a contracture of peroneal tendons. The PTT chronically contracts in order to counterbalance the peroneal prevalence and to mantain the medial arch height. The consequent instability is the peculiar pathomechanics of the cavus valgus foot. When a cavus valgus foot is subjected to overuse solicitations, the PTT may become inflamed and degenerated. In athletic patients in whom the dysfunction of the PTT impairs a pre-existing cavus val-

Fig 5. The PTT shows a bulbous enlargement in Stage II of degeneration. The flexor digitorum Iongus is identified prior to anastomose to PTT.

gus, an intervention of reconstruction of PTT supported by an arthroeresis of the subtalar joint may be indicated. The arthroeresis is a procedure performed on the lateral side of the affected foot with the aim of restraining the exaggerated motion of subtalar joint that leads to subluxation. The mechanism of action was studied and popularized by Burutaran, Recaredo-Alvarez, and Pisani. 21

The necessary procedures on the medial side (tenosynovectomy, PTT advancement, retensioning of the talo- navicular joint, PTT reconstruction) are performed as previously described. A short incision is performed anteriorly to the lateral malleolus. The extensor digitorum brevis is carefully dissected from the anterolateral aspect of the calcaneus until the floor of the sinus tarsi is reached. One must be careful not to enter the subtalar joint nor the sheath of the peroneal tendons. The surgeon over-corrects manually the valgus heel and the forefoot abduction. While the correction is firmly mantained a 4.5 cancellous screw is inserted into the floor of the sinus tarsi (Fig 7 A, B). The direction of the screw is parallel to the major axis of the leg. The device is screwed until the realignment of the heel is achieved. Over-correction must be avoided. The screw impinges against the lateral process of the talus thus impeding its inward rotation and plantar flexion. Further- more, the screw acts as a lever that prolongs the lateral wall of the calcaneus thus preventing the valgus of the heel. The screw is strictly extraarticular and only restrains the subtalar joint hypermobility. The weightbearing radiographs assess the reduction of the medial protrusion of the talar head (Fig 8 A, B). The restoration of the physiological range of motion of the subtalar joint highly reduces the strains upon the PTT and the structures of the medial side of the foot. The reconstruction and the repair of the medial structures of the foot are consequently protected by the arthroeresis against further elongation.

Ar throdeses

Arthrodeses are reserved for more severe deformities, for arthritic changes that involve subtalar joint and Chopart's joint, and for deformities that make these articulations irreducible after subluxation and eventually as a salvage

162 SCALA ET AL

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Fig 6. (A) Twenty-eight-year old amateur tennis player whose right foot shows swelling on the medial side and an enhanced heel valgus due to PTT rupture. (B) The photopodogram assesses the interruption of the lateral profile of the foot due to the heel valgus and the forefoot abduction. The height of the medial arch is relatively mantained, contrary to the pes planus. (C) Picture of the same patient who underwent PTT-FDL tenodesis and arthroeresis of the subtalar joint seen at 3-years follow-up. The correction of the heel valgus and talar head protrusion appears to be mantained. The patient remains a two-time-per-week tennis player. (D) The photopodogram assesses the restoration of the normal lateral profile of the foot, because the calcaneo-cuboid dislocation and forefoot abduction are reduced.


Fig 7. (A) Subtalar arthroeresis. (B) The cancellous screw is inserted into the floor of the sinus tarsi through a lateral approach of the foot. Lateromedial radiograph that shows the correct position of the screw into the sinus tarsi floor.

procedure. Isolated arthrodeses are (1) talo-navicular fusion, (2) calcaneo-cuboid and (3) subtalar fusion. More complex fusion are Chopart's (talo-navicular and calcaneo- cuboid) fusion and triple arthrodesis. Increased stresses and discomfort of the adjacent joints may intervene following articular fusion. Arthrodeses are seldom indicated in patients who are athletes because of the loss of mobility that these procedures imply.

P E R O N E A L T E N D O N S P A T H O L O G Y A N D S U R G I C A L P R O C E D U R E S

The peroneal tendons provide the dynamic control of flexibility/stability balance of the foot lateral column. Tendon elasticity and endurance are submitted to severe solicitation due to continuous motion of posterior tarsal bones during sports activities.

The peroneus longus and brevis tendons overlay ankle joint, subtalar joint, and calcaneo-cuboid joint while directed toward their distal insertion. Postural changes of these joints dramatically affect the contraction/relaxation mechanism of the peroneal muscle. Cavus varus foot featured by inversion of the subtalar joint is more prone to lateral ankle sprains, and peroneal tendons chronically

contract in order to counterbalance this tendency. Inflam- matory changes may arise following this condition.

A structured valgus forefoot may cause callosities on the plantar side of the first metatarsal head. In order to avoid this painful condition, the rearfoot is forced to supination while peroneal tendons develop a chronic peroneal contracture to control an exaggerated subtalar supination. The consequent stress upon peroneal tendons may lead to tenosynovitis and tendinitis. Both tendons are contained within a common fibro-osseous tunnel and synovial sheath. The lateral wall of the tunnel is the superior peroneal retinaculum; the medial wall is constituted by posterio talofibular, calcaneal fibular and posterior inferior tibiofibu- lar ligaments; the anterior wall is the posterior aspect of the lateral malleolus. The superior peroneal retinaculum is a fibrous band that originates from the posterior ridge of the fibula and introduces itself into posterior (Achilles tendon) and inferior (calcaneus) structures in a variable fashion. As a primary restrain to peroneal tendon dislocation and/or subluxation, it plays an important role in the setting of both acute and chronic tendon pathology and lateral ankle instability. 22

The inferior peroneal retinaculum, whose fibers insert on the lateral aspect of the calcaneus, is in continuity with the superior retinaculum. This retinaculum contains the common peroneal sheath. The peroneal tendon sheath is a structure that is adapted to the mechanical requirements of the region. It serves simultaneously as a guide and re- straint for the peroneal tendons and as a lateral stabilizer of the upper ankle joint. 23 The two tendons divide their route after the lateral malleolus: the peroneus brevis turns anteriorly to the distal insertion which is the tuberosity of the base of the fifth metatarsal; the peroneus longus undergoes two abrupt changes of direction while routing towards the lateral side of the first metatarsal base: first, at the tip of the lateral malleolus, where it lays posteriorly to the peroneus brevis; second, at the entrance of the cuboid groove. There is usually an enlargement of the tendon that contains a sesamoid bone at the lateral edge of the cuboid. Injuries of the peroneal tendons are: peritendinitis, tendini -~ tis, ruptures (longitudinal, in continuity and transverse) and dislocation.

Surgical Procedures for Peroneal Tendinitis and Ten- don Tears

Inflammatory conditions of the peroneal tendon are paratenonitis (Fig 9), tendinosis, and tendinitis. The pulley action and abrupt change in the direction of the peroneal tendon at the lateral malleolus have been held responsible for the onset of peroneus longus tendinitis. 4 Attritional etiology is considered responsible in case of peroneal tendon diseases. Stenosing tenosynovitis may depend on friction against a well-developed peroneal tubercle. In congenital anomalies, such as accessory muscle which is featured by bifurcation and trifurcation of the tendons, attritional changes are present. The surgical section of the anomalous tendon is sufficient to relieve symptoms.

Pathologic findings in case of peroneal tendon ruptures may vary: bulbous enlargement, tendon attenuation, longitudinal tears, and ruptures in continuity (Fig 10).

164 SCALA ET AL

Fig 8. (A) Dorsoplantar view that assesses the lateral displacement of the forefoot and the medial protrusion of the talar head. (B) After the arthroeresis the restoration of the talo-navicular coverage angle is appreciable,

Cadaveric studies were per formed in order to investi- gate the injury mechanism of the longitudinal tears that occur to peroneus brevis and longus tendon. The findings assessed that the tear of the tendon could occur in the 25 ° to 15 ° range of plantar flexion as the peroneus longus impinged against the tip of the fibula and as the peroneus brevis impinged against the lateral wall of the peroneal groove or against the longus tendon. 24

Fig 9. Intraoperative picture that shows paratenonitis with tendinosis of peroneal tendons. The abundant vascular inflammatory tissue is removed from the synovial sheath.

Acute peroneus longus tears are not rare and may occur after a severe sport injury or a trauma. A " p o p " may be heard at the time of the injury. In case of severe impairment, featured by pain and weakness, a direct repair of the tendon is per formed with a nonabsorbable suture (4-0 braided Dacron).

The tear occurs alone or in association with peroneus brevis tendon. The tendon may show a single or a multiple tear. The tear may be longitudinal, transverse partial or complete. A fracture of the os pe roneum may also be associated. A varus foot was present in some of the 14 cases. The tears were located on the lateral calcaneus distally and in the cuboid groove. In case of acute onset, surgical procedures usually necessary are: tendon repair, bony f ragment excision, associated conditions corrected (repair peroneus brevis, reconstruction of the lateral ligaments). The high shear stresses within the tendon as it turns beneath the foot may be the major factor in produc- ing the longitudinal tear. Chronic tears do not recognize an initiating event and the onset of symptoms is gradual. When a mass is present on the lateral side, a f ragmented and proximally migrated os peroneus may be the cause. Radiographic assessment of proximal migrat ion of the os pe roneum is helpful in making the diagnosis. Abnormal solicitation due to overuse and at tenuated or absent lateral ankle l igament complex may be responsible for the peroneus longus tear. The feature of the chronic tear of the

TENDINOPATHIES OF THE ANKLE JOINT 1 6 5

Fig 10. (A) Ttie CT scan shows the pathologic enlargement of the peroneal tendon and sheaths. (B) The surgical exploration assesses the tendon degeneration and longitudinal rupture.

peroneus longus is longitudinal. Surgical repair provides for excellent outcome whether the tear is acute or chronic although patients with acute onset of symptoms show better results than those without an initiating event precipi- tating symptoms. In case of chronic onset, recommended surgical procedures are excise os peroneum, repair tear, and correct associated conditions (repair peroneus brevis, reconstruct ligaments). Isolated transverse rupture of the peroneus brevis is an unusual occurrence. A free split thickness tendon graft is the suggested treatment in such a case. 2s

Painful os peroneus syndrome may be the cause of plantar lateral foot pain. This syndrome results from a spectrum of condition involving fracture or separation of os peroneum, callus formation after the os peroneum fracture or separation resulting in a stenosing peroneus longus tenosynovitis, attrition or partial rupture of the peroneus longus around the os peroneum, rupture of peroneus longus distally or proximally to the os peroneum, presence of a gigantic os peroneum which entraps the os peroneum, and/or the peroneus longus tendon. Surgical treatment for such a syndrome includes excision of the os peroneum (Fig 11) and repair of the peroneus longus tear; excision of the os peroneum and degenerated peroneus

longus tendon with tenodesis of the remaining remnant of peroneus longus to the peroneus brevis tendon.

Luxation of Peroneal Tendons

The mechanism of injury is a forceful, passive extension of the ankle joint, with the foot in slight evertion, while peroneal tendons contract vigorously. The calcaneofibular ligament tenses in extension reducing the room of the peroneal tendon, while the change of direction is at its peak. Eversion contributes to push the tendons against the retinaculum thus ripping periostium and retinaculum fibers out of the posterior ridge of the distal fibula. Bone chips may be pulled away during the dislocation. A shallow or malaligned posterior aspect of the distal fibula and attenuation or laceration of the retinaculum, the fibrous lip and periosteum seem to be involved in the subluxation. Although several studies have been under- taken to assess the anatomic predisposing factors, no effective factor was detected to explain the onset of the peroneal tendon subluxation. 26 Acute dislocation occurs with pain and a snapping sensation. A bone fragment around the profile of lateral malleolus is an infrequent radiologic finding. The reduction of the peroneal tendon is usually easy to perform with the foot in equinus and inversion. Swelling at the posterior side of the malleolus is commonly observed. The dislocation may be missed, and ankle sprain is usually the misleading diagnosis.

Nonsurgical treatment of the acute dislocation includes taping or bandage with compression over the dislocated tendons area. A well-molded plaster cast is also recommended. Immobilization period varies from 4 to 6 weeks.

Unfortunately recurrent dislocations may occur after conservative therapy. Surgical treatment of recurrent dislocation of the peroneal tendons must be addressed to the primary pathology involved. Several surgical techniques have been developed to face the different changes that the surgeon may encounter at the time of surgery.

1. Acute rupture of the tendon sheath and retinaculum. Good results following direct suture of the sheath and of the torn retinaculus have been reported. 27 The repair of the rupture is performed by drilling three or four tunnels through the malleolus in which absorbable sutures are passed from the anterior to posterior side. The edge of the

Fig 11. A painful os peroneus that impinges within the groove for the peroneus Iongus is shown before the removal. The os peroneus is overhanged by the peroneus brevis.

166 SCALA ET AL

laceration is anchored and is securely fixed against the posterior margin of the peroneal malleolus. The sutures are then knotted on the anterior side of the lateral malleolus. No other sutures are usually needed as long as the posterior portion of the sheath is sound and remains untouched. A weightbearing cast is applied and held for 4 to 5 weeks. A gradual rehabilitation program is started at the removal of the cast.

2. Enlargement of the sheath, anterior luxation of the tendons with detachment of the periosteal retinacular fibers. The suggested surgical techniques are: (a) A rectangular fibroperiosteal flap is carved on the anterolateral aspect of the distal fibula (4 cm height and 2 cm width). The flap remains secured to the bone along the posterior ridge of the malleolus and is then turned over and sutured to the posterior margin of the peroneal sheath. (b) The pouch containing the dislocated peroneal tendon is incised. The anterior part of this pouch is sutured to the posterior ridge of the malleolus by means of nonresorbable Nylon passed within previously drilled bone tunnels. The sheath is then closed, paying special attention to secure the inferior and posterior margin to the calcaneofibular ligament.

3. When the fibroperiosteal tissues of sheath and of retinaculum is too attenuated and the layer is so thin that it may be frayed by sutures, the reconstruction of the postero- lateral retinaculum by means the Jones procedure 28 is recommended. A strip of Achilles tendon is obtained from the lateral aspect (6 cm height and 5 cm of width). A tunnel is drilled through the lateral malleolus at 1 cm from its distal tip. The peroneal tendons are reduced into their groove and the Achilles strip is then passed through the tunnel and is sutured to the anterolateral fascial structures of the ankle. Particular care must be taken when suturing the Achilles strip with the extended foot in order to avoid a limitation of the extension.

4. Different procedures have been described with the aim to modify the osseous posterior surface of the lateral malleolus. (a) A groove-deepening procedure is performed when a shallow surface of the lateral malleolus is the main factor of the peroneal tendons dislocation. 29 (b) Osteoto- mies of the lateral malleolus. The procedure is performed by rotating the osteotomized malleolus posteriorly to retain the tendon sheath. Following other techniques a bone block is performed in order to obtain an osseous hinge that prevents the tendon dislocation. The bone block is then posteriorly oriented or moved inferiorly. 3° These techniques are not commonly in use because of the risk of weakening of the malleolus, impingements of the displaced bone against the surrounding structures, pain due to the prominence of the screw and the displaced bone, and consequent discomfort with shoes. The same techniques must, on the other hand, be kept in mind when, in case of failure of previous procedures, a surgical revision becomes necessary.

5. Transposition of the peroneal tendon under the calcaneofibular ligament. The method was first described by Platzgummer in 1967. After dividing the calcaneofibular ligament near its origin and removing the fatty tissue in the space between this ligament, the posterior talofibular ligament and the lateral capsule of the subtalar joint, the peroneal tendons are placed behind the lateral malleolus and under the calcaneofibular ligament, which is recon-

structed by suture in order to create an efficient retain- ment. n The tendon sheaths are not placed under the calcanealfibular ligament. Gliding tissue forms in the new tendon bed. During the extreme plantarflexion, the space for the peroneal tendon narrows because the calcaneofibular ligament is gliding upward posteriorly at the medial side of the lateral malleolus, thus creating some impingement of the transposed tendons between the calcaneofibular ligament, the posterior talofibular ligament, the malleolus, and the protruding posterior rim of the talocalcaneal joint. The calcaneofibular ligament tenses during extension while relaxes during flexion leaving enough room for the transposed tendons. The calcaneo fibular ligament may be detached with a bone block and reinserted with a screw or with two crossed Kirschner wires. The calcaneal insertion of the ligament may be separated with a bone block and fixed with a screw or nail. The peroneal tendons may be divided before being rerouted under the calcaneofibular ligament.

FLEXOR HALLUCIS LONGUS TENDON PATHOLOGY AND SURGICAL PROCEDURES

The tendon of the Flexor Hallucis Longus (FHL) lies in a groove that crosses the posterior surface of the distal end of the tibia, the posterior surface of the talus, and the under-surface of the sustentaculum tall of the calcaneus. Flexor Hallucis Longus diseases related to sports activities are: tendonitis, partial ruptures, longitudinal tears, complete ruptures occurring in different sites along its course. Repetitive solicitations are the cause of tendinitis and synovitis while the mechanism of injury of complete rupture is a forced extension of the toes. Overuse lesions are featured by tendon nodularity, fusiform, thickering, erosion. Pathologic findings of the partial rupture are longitudinal tears, synovitis, and scar tissue around the tendon. Complete ruptures show bulbous, rounded tendon stumps and abnormal scarred tendon. The main symptom of FHL is triggering which may arise following several different conditions: entrapment of the FHL tendon in the fibro-osseous sheath behind the sustentaculum tall, acute traumatic FHL tendon rupture just proximal to its insertion on the hallux, rupture of the FHL in the midfoot. 32

Surgical Procedures for FHL Tendinitis

When tendinitis and partial rupture occur within the retromalleolar fibro-osseous tunnel flexor retinaculum release is indicated.

Surgical Procedures for FHL Partial Ruptures

Indication for surgery are: medial hindfoot pain that impairs the sports activity, pain reproduced with active plantar flexion of the great toe and lesser toes against resistence.

The surgical exploration shows scar tissue involving the tendon sheath of FHL and Flexor Digitorum Longus, tenosynovitis, impingement of the tendons in the scar tissue, longitudinal split tears# 3 The scar tissue is bluntly removed; tenosynovectomy is performed; the FHL muscle from the tendon is excised in order to leave the muscular


t i s sue p r o x i m a l l y to the m e d i a l m a l l e o l u s ; the l o n g i t u d i n a l sp l i t of the F H L t e n d o n is r e p a i r e d u s i n g a c o n t i n u o u s 6-0 m o n o f i l a m e n t n y l o n c losure , w i t h the k n o t s b u r i e d w i t h i n the t e n d o n ; the s y n o v i a l shea th s a re n o t s u t u r e d c losed .

Af t e r the surgery , i m m o b i l i z a t i o n is h e l d for i w e e k ; a t the r e m o v a l of cast , ac t ive e x t e n s i o n a n d f lex ion exerc i se of the a n k l e a n d toes a re s t a r t ed .

Surgical Procedures for FHL Complete Rupture

C o m p l e t e r u p t u r e s of F H L a p p e a r to b e w e l l - t o l e r a t e d b y the pa t i en t s . Su rg ica l r e p a i r is n o t b e l i e v e d m a n d a t o r y b y al l of us. The i n d i c a t i o n s for su rg i ca l t r e a t m e n t are (1) h y p e r e x t e n s i o n d e f o r m i t y of the g rea t toe; (2) loss of g r e a t toe p r e s s u r e a g a i n s t the f loor; a n d (3) p r e v e n t i o n of c o c k - u p toe de fo rmi ty . C o m p l e t e r u p t u r e s occur d i s t a l l y a n d p r i m a r y r e p a i r is the t r e a t m e n t of choice. S e c u r i n g the d i s t a l F H L t e n d o n to the F l exo r H a l l u c i s Brevis m u s c l e p r e v e n t s the c o c k - u p de fo rmi ty . I n t e r s t i t i a l - t y p e r u p t u r e w a s r e p o r t e d 34 at the l eve l of the m e t a t a r s a l h e a d i n t e r se sa - m o i d r e g i o n w h e r e the F H L t e n d o n c o m e s t h r o u g h the f i b ro -o s seous t u n n e l b e t w e e n the t w o s e s a m o i d b o n e s e n c a s e d in the F lexor H a l l u c i s Brevis . The l e s ion w a s t r e a t e d b y p r i m a r y s u t u r e r o u t i n g the t e n d o n in i ts n o r m a l loca t ion . A f t e r surgery , a s h o r t leg cas t w i t h e x t e n d e d toe p l a t e w a s h e l d for 4 weeks . A p n e u m a t i c f r ac tu re w a l k e r w a s u s e d for c o n t i n u e d p r o t e c t i o n of the toe f r o m fo rced ex tens ion . A c t i v e f l ex ion w a s a l l o w e d at 2 m o n t h s a n d p r o t e c t i o n w a s d i s c o n t i n u e d at 3 m o n t h s . The r e p a i r r e s u l t e d in n o ac t ive f l ex ion at the IP joint . The s t i f fen ing of the IP jo in t a f te r d i s t a l F H L r e p a i r a lso m a y occur, b u t it does n o t p r o v e to b e a m a j o r d i s a b i l i t y o r to cause a f u n c t i o n a l defici t .

In a r e p o r t e d case of F H L r u p t u r e u n d e r the s u s t e n t a c u - l u m tali , s5 w i t h 7 c m s e p a r a t i o n b e t w e e n the t w o s t u m p s , t e n o d e s i s of the F H L to the F lexor D i g i t o r u m L o n g u s p r o x i m a l a n d d i s t a l to the s u s t e n t a c u l u m ta l i p r o v e d to be effect ive. Tenodes i s of the d i s t a l s t u m p of the F H L to the F lexor H a l l u c i s Brevis a t a t e n s i o n is r e c o m m e n d e d to p r e v e n t h y p e r e x t e n s i o n of the ha l lux .

Surgical Procedures for the Entrapment and Trigger- ing of the FHL Tendon

E n t r a p m e n t of F H L w i t h t r i g g e r i n g of the t e n d o n m a y occur f o l l o w i n g a d i f fe ren t cond i t i on : t e n d o n e n t r a p m e n t in ca l canea l f r ac tu re f r a g m e n t s or in f r ac tu re f r a g m e n t s of the ank le , e n t r a p m e n t of the F H L in the f ib ro -osseus s h e a t h b e h i n d the t a lus a n d b e n e a t h the s u s t e n t a c u l u m ta l i r e su l t - i ng in t r i g g e r i n g of the ha l lux . E n t r a p m e n t of the F H L af ter t r e a t m e n t of a f ibu la f rac tu re w a s r e p o r t e d . 32 The a d h e - s ions of the F H L m u s c u l o t e n d i n o u s un i t to f ibu la f rac tu re ca l lus a n d the i n t e r o s s e o u s m e m b r a n e are r e s p o n s i b l e for the f ixed c o n t r a c t u r e of the ha l lux . S u g g e s t e d s u r g e r y is the e x p l o r a t i o n of the t e n d o n a n d re lease of the cause of e n t r a p m e n t a n d a d h e s i o n . 32

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168 SCALA ET AL

32. Leitschuh PH, Zimmerman JP, Uhirchack JM, Arciero RA, Bowser L: Hallux flexion deformity secondary to entrapment of the flexor ha)lucis longus tendon after fibular fracture. Foot and Ankle Intern 16:232-235,1995

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Tendinopathies of the ankle joint