Journal of the American Academy of Orthopaedic Surgeons 112 The loss of function of the posterior tibial tendon has been associated with the development of a progres- sive flatfoot deformity in adults and children. 1,2 The exact etiology of this condition remains contro- versial. While rupture of the pos- terior tibial tendon has been asso- ciated with various underlying pathologic conditions, the idio- pathic nature of this problem in most patients adds to a growing level of interest in the problem among the general orthopaedic community. There is a sizable group of patients in whom symp- tomatic discomfort is associated with dysfunction of this tendon as well as concomitant deformities. The purpose of this report is to illustrate the spectrum of posterior tibial tendon insufficiency, to high- light recently described techniques for reconstruction, and to review options for surgical and nonopera- tive management. History The original description of posteri- or tibialis insufficiency and its asso- ciated tendinitis is credited to Kulowski in a 1936 article. Fowler 3 and Williams 4 described early series of patients who had apparent tendinitis of the posterior tibialis tendon that required surgical treat- ment. However, for many years, few reports were published about this pathologic condition. Consid- erable interest in posterior tibial tendon insufficiency has developed over the past 15 years. This interest has largely stemmed from efforts to understand the pathomechanics of the hindfoot as well as reports of clinical series describing a variety of methods for surgical treatment of this condition. Dr. Beals is Assistant Professor, Department of Orthopedics, University of Utah School of Medicine, Salt Lake City. Dr. Pomeroy is Clinical Assistant Professor of Orthopaedic Surgery, University of New England; and Director, Portland Orthopedic Foot and Ankle Center, South Portland, Me. Dr. Manoli is Professor and Chairman, Department of Orthopedic Surgery, University of South Alabama, Mobile. Reprint requests: Dr. Beals, University of Utah School of Medicine, 50 North Medical Drive, Salt Lake City, UT 84132. Copyright 1999 by the American Academy of Orthopaedic Surgeons. Abstract Posterior tibial tendon insufficiency is the most common cause of acquired adult flatfoot deformity. Although the exact etiology of the disorder is still unknown, the condition has been classified, on the basis of clinical and radio- graphic findings, into four stages. In stage I, there is no notable clinical deformity; patients usually present with pain along the course of the tendon and local inflammatory changes. Stage II is characterized by a dynamic deformity of the hindfoot. Stage III involves a fixed deformity of the hindfoot and typically also a fixed forefoot supination deformity but no obvious evi- dence of ankle abnormality. In stage IV, ankle involvement is secondary to long-standing fixed hindfoot deformities. The initial treatment of patients in any stage should be nonoperative, with immobilization, a nonsteroidal anti- inflammatory drug, and perhaps an orthotic device. The role of corticosteroid injections continues to be controversial. When nonoperative management fails, the treatment options consist of soft-tissue procedures alone or in com- bination with osteotomy or arthrodesis. Stage I insufficiency is generally treated with debridement and tenosynovectomy. Soft-tissue transfer does not appear to correct the underlying deformity in stage II disease; however, there is growing interest in joint-sparing operations that attempt to compensate for the underlying deformities with osteotomies or arthrodeses, supplemented with dynamic transfers to replace the insufficient posterior tibial tendon. Subtalar, double, or triple arthrodesis is the procedure of choice for stage III disease, frequently in conjunction with heel-cord lengthening. Tibiocalcaneal arthrodesis or pantalar arthrodesis is most commonly used to treat stage IV disease. J Am Acad Orthop Surg 1999;7:112-118 Posterior Tibial Tendon Insufficiency: Diagnosis and Treatment Timothy C. Beals, MD, Gregory C. Pomeroy, MD, and Arthur Manoli II, MD Timothy C. Beals, MD, et al Vol 7, No 2, March/April 1999 113 Anatomy and Biomechanics The posterior tibial muscle origi- nates on the posterior aspect of the tibia, the fibula, and the interos- seous membrane. It courses poste- riorly and medially around the ankle in a groove adjacent to the medial malleolus and inserts on the midfoot in the area of the navicular tuberosity. The tendon has bands that attach to the plantar aspect of the cuneiforms; the second, third, and fourth metatarsals; and the sustentaculum tali. It runs posteri- or to the axis of the ankle joint and medial to the axis of the subtalar joint. Therefore, the tendon func- tions as a plantar-flexor of the ankle and as an invertor of the sub- talar joint complex. The posterior tibial muscle initi- ates the process of inversion of the hindfoot during gait, bringing it into a neutral position and maxi- mizing the mechanical advantage of the more laterally positioned Achilles tendon as the individual rises onto the forefoot. The poste- rior tibial muscle truly drives the position of the hindfoot and deter- mines the flexibility of the foot by its control over the transverse tarsal joints. The loss of the force of inversion of the muscle explains why patients with posterior tibial tendon insufficiency have only a limited ability, or are completely unable, to rise onto their toes from a position of single-leg stance. The posterior tibial muscle is normally opposed by the peroneus brevis, and it has been theorized that it is the lack of opposition of the per- oneus brevis muscle that leads to the clinical deformities recognized in patients with rupture or dys- function of the posterior tibial ten- don. The posterior tibial and per- oneus brevis muscles both function during the midstance phase of gait. Several pertinent anatomic fac- tors relate to reconstruction tech- niques and explain the problems patients experience with insuffi- ciency of the posterior tibial ten- don. These include the fact that the posterior tibial muscle is large in comparison to those that can be transferred to replace it. It has a cross-sectional area of 16.9 cm 2 , compared with 5.5 cm 2 for the flex- or digitorum longus muscle and 6.7 cm 2 for the peroneus brevis muscle. The medial capsular and ligamentous structures of the hind- foot and midfoot certainly play a role in the development of flatfoot deformities. The talonavicular joint capsule, as well as the spring- ligament 5 and deltoid-ligament complexes, have been implicated in the progressive loss of the medi- al longitudinal arch of the foot and the ankle dysfunction seen in long- standing cases of posterior tibial tendon insufficiency. Diagnosis The diagnosis of posterior tibial tendon insufficiency is primarily a clinical one. Patients typically complain of pain medially around the ankle that may radiate into the arch of the foot. Some patients in the later stages of the condition complain of pain on the lateral aspect of the foot, where the calca- neus abuts against the fibula, due to an excessive valgus position of the hindfoot. Roughly half of all patients give a history of some sort of trauma that was initially thought to be a sprain. Patients often expe- rience swelling along the course of the posterior tibial tendon and sig- nificant pain, most typically several centimeters proximal to the inser- tion onto the navicular tuberosity. Pain is exacerbated by activity, and the ability to walk distances de- creases. Some patients present simply with pain and apparent inflammation along the tendon without any evidence of clinical deformity, but most patients have some collapse of the foot. The rate of development of clini- cal deformity is variable, and there are no adequate studies of the nat- ural history of posterior tibial ten- don insufficiency. In some pa- tients, the deformity increases, and eventually the hindfoot valgus, notable even during relatively early stages of the condition, be- comes fixed. In the latest stages of the condition, the ankle is affected and has a tendency toward valgus tilting from laxity of the medial deltoid complex. Clinical evaluation includes observing the patient in a standing position. When viewed from be- hind, the Òtoo many toesÓ sign is typically seen, which is evidence of abduction of the midfoot relative to the hindfoot. 6,7 Excessive hindfoot valgus is noted in the affected limb, as well as loss of the longitudinal arch when viewed from either the side or the front. Typically, soft- tissue swelling around the medial aspect of the ankle is evident. The tissues below the medial malleolus appear prominent due largely to excessive hindfoot valgus (Fig. 1). Patients asked to rise onto their Fig. 1 Clinical appearance of a patient with stage II posterior tibial tendon insuffi- ciency. Note the too-many-toes sign on the left, the excessive hindfoot valgus, and medial soft-tissue swelling. Posterior Tibial Tendon Insufficiency Journal of the American Academy of Orthopaedic Surgeons 114 toes from a position of single-leg stance either are completely unable to comply or can do so only to a limited degree. They may attempt to compensate by vaulting forward to raise themselves with use of the Achilles tendon. While some authors dismiss its utility, manual testing of muscle units is helpful for both diagnosis and the determination of treatment options. Resistance against the tib- ialis posterior is assessed, as well as testing of the peroneus brevis, flex- or hallucis longus, and flexor digi- torum longus. To evaluate the tib- ialis posterior, the foot is placed in an everted, plantar-flexed position, and the patient is asked to invert the foot. This method is more accurate than testing the foot in an inverted position; with that tech- nique, the function of the tibialis anterior may confuse the examiner. Contracture of the Achilles ten- don complex is often noted when the foot is placed in a reduced posi- tion. In cases of excessive hindfoot valgus, patients are able to achieve a relatively dorsiflexed position by rotation through the transverse tarsal joints into a Òcompensated equinusÓ position. The hindfoot equinus often seems most directly related to the gastrocnemius mus- cle and is not necessarily related to the entire gastrocnemius-soleus complex. This distinction is made by testing with the knee extended and flexed. During gait evaluation, recruitment of the long extensor tendons can be seen in patients who have a tight Achilles tendon complex. Thorough evaluation is neces- sary to ensure that insufficiency of the posterior tibialis tendon is an isolated problem and not indica- tive of a more generalized condi- tion, such as rheumatoid arthritis or seronegative arthropathy. Ex- amination of the contralateral limb and upper extremities is often helpful. Radiographic evaluation should include four weight-bearing films: an anteroposterior view of both ankles, an anteroposterior view of both feet, and lateral foot and ankle radiographs of each side. This allows comparison in patients who have unilateral disease and often serves as an excellent teaching tool when explaining the nature of the problem to the patient. Arthrosis of the hindfoot joints should be determined, as this may affect treatment. Typical deformity in- cludes apparent shortening of the hindfoot on the weight-bearing anteroposterior ankle radiograph, which is indicative of collapse through the subtalar joint complex. A rare finding in advanced poste- rior tibial tendon insufficiency is an ossicle in the medial ligament com- plex, which seems associated with failure of the deltoid. On weight-bearing lateral radio- graphs, the inclination of the talus is plantarward in comparison to normal, with collapse typically through the talonavicular joint. On some occasions, the collapse seems equally evident through the navic- ulocuneiform and tarsometatarsal articulations. Comparison of the inferior portion of the medial cuneiform to the inferior portion of the fifth metatarsal can be helpful to allow objective measurement of the degree of collapse (Fig. 2). Anteroposterior foot radiographs typically demonstrate lateral peri- talar subluxation of the navicular and associated abduction of the midfoot. The amount of the talar head that is uncovered appears increased in comparison to the con- tralateral side. Evaluation with adjunctive mo- dalities, such as tomography, injec- A B Fig. 2 A, Lateral weight-bearing radiograph of a foot with stage II posterior tibial tendon insufficiency. The inferior border of the medial cuneiform (medial column) is even with the base of the fifth metatarsal (lateral column). Note the plantar inclination of the talus. B, The normal contralateral foot is shown for comparison. Timothy C. Beals, MD, et al Vol 7, No 2, March/April 1999 115 tion tenography, ultrasonography, and magnetic resonance imaging, has been advocated by some. Indeed, there are case reports docu- menting utility in cases in which the diagnosis is uncertain. Although this is not routinely recommended, such tests should be considered. Classification of Posterior Tibial Tendon Insufficiency Johnson and Strom 7 initially de- scribed a classification scheme for posterior tibial tendon insufficiency. Although the classification is not predictive and does not consider the contracted gastrocnemius, the initial three-stage scheme is useful in developing algorithms for treat- ment. However, it has been found helpful to also consider a fourth stage of the disorder in developing a treatment plan. Stage I Stage I is defined as the absence of a fixed deformity of the foot or ankle with the possible exception of a contracted gastrocnemius-soleus complex. The foot is in normal alignment when the patient is stand- ing. Patients typically present with pain along the course of the poste- rior tibialis tendon and evidence of local inflammatory changes. Stage II Stage II is characterized by a dynamic deformity of the hindfoot. The standing patient displays an increased degree of hindfoot valgus, apparent weakness of tibialis poste- rior function, the characteristic too- many-toes sign, and inability to do a single-leg heel rise. However, pat- ients still have a relatively normal arc of subtalar motion, and the foot can be placed into a neutral posi- tion, with the possible exception of contraction of the gastrocnemius- soleus complex. Stage III Patients with stage III posterior tibial tendon insufficiency have a fixed deformity of the hindfoot. With the hindfoot in a fixed valgus position, it is not possible to re- duce the talonavicular joint. Typi- cally, these patients also have an accompanying fixed forefoot supi- nation deformity that is a compen- satory change to accommodate the hindfoot valgus in order to main- tain a plantigrade foot. Patients with stage III disease do not have obvious evidence of ankle abnor- malities. Stage IV A relatively small subset of patients have ankle involvement secondary to long-standing fixed deformities of the hindfoot. They may present with ankle arthritis due to eccentric loading of the ankle. Some have a valgus talar tilt with loss of competence of the del- toid ligament complex. Pathophysiology The etiology of posterior tibial ten- don insufficiency is elusive. In an epidemiologic study, Holmes and Mann 8 correlated the development of posterior tibial tendon insuffi- ciency to hypertension and obesity. This condition affects more women than men. Controversy exists about the development of posterior tibial tendon insufficiency in patients with rheumatoid arthritis, with some authors emphasizing the role of the tendon and others implying dysfunction secondary to subtalar arthrosis. The blood supply in the region of tendon failure has been stud- ied. 9,10 Some theorize that there is an area of diminished perfusion at the site of tendon failure, which may have implications regarding the etiology of the injury and its apparent inability to heal. Mechani- cal causes of posterior tibial tendon insufficiency have been described, including an association with a contracted gastrocnemius-soleus complex. Recent immunohistologic stud- ies imply a lack of an inflammatory appearance in stage II disease. The histologic appearance is consistent with mechanical failure of the col- lagen architecture of the tendon in the area of elongation and rupture, with mucoid degeneration. Com- plete rupture of the tibialis poste- rior tendon is not common, as most patients have longitudinal failure of the tendon substance. In gross appearance, the tendon has been described as being the color of poached fish, often with longitudi- nal tears on the lateral side of the tendon (Fig. 3). In cases of chronic posterior tibial tendon insufficiency, the gross appearance and histo- logic structure of the tendon are abnormal. Nonoperative Management The initial management of patients who present in any stage of poste- rior tibial tendon insufficiency is nonoperative. Some success has been achieved by immobilization of patients who have symptoms of acute tendinitis with or without deformity. A trial with an accom- modative orthotic device that is supportive of the medial longitudi- nal arch is usually worthwhile. Although there are no published studies documenting the efficacy of orthotic devices in the treatment of the various stages of this condition, there is certainly a population of patients who report a decreased level of symptoms associated with the use of such a device. An ankle brace or ankle-foot orthosis will be helpful to some patients. Nonster- oidal anti-inflammatory medication can decrease pain and associated swelling. Posterior Tibial Tendon Insufficiency Journal of the American Academy of Orthopaedic Surgeons 116 The role, benefit, and appropri- ateness of corticosteroid injections for this problem continue to be controversial. Published reports associate the use of steroid injec- tions with rupture of the tendon, although it is possible that in these instances rupture might have occurred without injection due to the underlying pathologic changes in the tendon. There are no con- trolled studies of the use of such injections. Therefore, at this time, routine use of injections in this area cannot be recommended as part of the nonoperative treatment of this condition. Operative Management The operative treatment of patients in whom nonoperative manage- ment has failed consists of either soft-tissue procedures alone or soft- tissue procedures combined with either osteotomies or arthrodesis. It is important to account for all the fixed and dynamic structural defor- mities present when defining a spe- cific operative plan for a given patient. Stage I Patients who have stage I poste- rior tibial tendon insufficiency often do not have a notable clinical defor- mity. They have an inflammatory condition involving the tendon, but the tendon remains competent in terms of function, and there are no secondary deformities that have developed due to the tenosynovitis. These patients have been treated with debridement of the tendon and tenosynovectomy around the posterior tibial tendon. There is only one recent study providing follow-up, and it supports the con- cept that the combination of debridement and tenosynovectomy is effective in relieving pain. 11 However, there are no published studies on this patient population that provide long-term follow-up data. Consideration could be given to augmentation of the posterior tibial tendon with the flexor digito- rum longus and to a gastrocnemius or heel-cord lengthening. Stage II It is in the treatment of this sub- set of patients where there is the greatest degree of controversy regarding the optimal surgical management. The historical foun- dation for treatment of this stage of posterior tibial tendon insufficiency is provided by a study reporting on the debridement of the posterior tibial tendon and transfer of the flexor digitorum longus to the navic- ular. 1 The results in 17 patients with a mean follow-up of less than 3 years have been very acceptable in terms of relieving pain. How- ever, it appears that the soft-tissue transfer does not correct the under- lying deformity. A recent article describes the results in a series of 13 patients fol- lowed up for a mean of 27 months after primary repair of the poste- rior tibial tendon and tenodesis of the flexor digitorum longus. 12 The results were considered to support the idea that these procedures re- lieve pain and improve the ability to ambulate. Similarly, good re- sults have been achieved with spring-ligament repair or recon- struction in addition to tendon transfer. 5 There is growing interest in oper- ations for stage II disease that attempt to compensate for the under- lying deformities and deforming forces with osteotomies or arthrode- ses. The bone procedures are sup- plemented with dynamic transfers to replace the insufficient posterior tib- ial tendon. Recent reports 13,14 have highlighted the early successful results of joint-sparing operations, such as a medializing osteotomy of the calcaneal tuberosity in addition to tendon transfer and a procedure that combines a medializing cal- caneal osteotomy, a lateral columnÐ lengthening osteotomy through the anterior calcaneus, a flexor digito- rum longus tendon transfer to the medial cuneiform, and heel-cord lengthening (Fig. 4). These two stud- ies demonstrate improved radio- graphic appearance, and the study by Pomeroy and Manoli 14 docu- ments statistically significant im- Fig. 3 Gross appearance of a degenerated posterior tibial tendon. Note the disruption of the fibers on the lateral side of the tendon. Timothy C. Beals, MD, et al Vol 7, No 2, March/April 1999 117 provement in function as indicated by the score on the ankle-hindfoot rating scale of the American Ortho- paedic Foot and Ankle Society. 15 The early reports of the success of joint- sparing operations allow optimism that it may be possible to treat stage II posterior tibial tendon insufficiency with procedures that do not necessi- tate a significant loss of hindfoot motion and adaptability. Lateral-column lengthening through the calcaneocuboid articu- lation with medial soft-tissue reconstruction has been advocated. The biomechanical and radio- graphic implications of such proce- dures have been studied by Sangeorzan et al 16 and Deland et al. 17 Subtalar arthrodesis is still suggested by many experienced foot and ankle surgeons, both alone and in concert with medial soft- tissue debridement and/or tendon transfer. The results of a study of patients treated with isolated talo- navicular arthrodesis demonstrated improved function and decreased pain. 18 In another study, 19 the implications of a talonavicular fusion in terms of the effect on hindfoot motion implied a signifi- cant loss of mobility. Stage III The foot with stage III posterior tibial tendon insufficiency has fixed deformities that cannot be corrected by osteotomies or soft-tissue proce- dures alone. Typically, there is some degree of arthrosis present in the subtalar joint complex. The proce- dures of choice in this stage of the disease include subtalar arthrodesis, double arthrodesis, and triple ar- throdesis. These are frequently done in conjunction with heel-cord length- ening. The arthrodesis selected should be able to correct all of the deformities. Once the subtalar joint has been taken out of an excessive degree of hindfoot valgus, fixed fore- foot supination necessitates a talo- navicular arthrodesis to rotate the foot into a plantigrade position. In some cases with more extreme defor- mity, it may even be necessary to perform an operation to plantar-flex the first ray if full correction of the deformity cannot be accomplished with a triple arthrodesis. The funda- mental goal is a plantigrade foot in a good position that supports the ankle in optimal alignment. Graves et al 20 reported on 17 patients who had undergone triple arthrodesis, 10 of whom had poste- rior tibial tendon insufficiency. The mean follow-up interval was 3 1 Ú2 years. The postoperative complica- tions were significant, and the authors recommended that triple arthrodesis be reserved as a salvage procedure. They also emphasized the risk of increased arthrosis in joints adjacent to the arthrodesis. Stage IV Patients with long-standing severe hindfoot valgus deformities and secondary ankle arthrosis are difficult to treat. Fortunately, few patients fall into this category. Most commonly, tibiocalcaneal arthrodesis or pantalar arthrodesis is performed to address all of the deformities simultaneously. Summary Posterior tibial tendon insufficiency is a disorder with a broad spectrum of clinical presentations. It is essential that treatment be closely correlated to the particular static and dynamic deformities in the patient. The classification system initially outlined by Johnson and Strom 7 is helpful in determining A B Fig. 4 Preoperative (A) and postoperative (B) radiographic appearance of a patient who underwent a medializing calcaneal tuberosity osteotomy and lateral columnÐlengthening calcaneal osteotomy. Posterior Tibial Tendon Insufficiency Journal of the American Academy of Orthopaedic Surgeons 118 the stage of disease and the treat- ment options available. However, without a documented natural his- tory of the disorder or a known time frame for the progression from one stage to another, it re- mains a challenge to counsel pa- tients regarding the optimal treat- ment. Recently described joint- sparing operations and limited arthrodeses combined with soft- tissue reconstruction allow opti- mism that patients with this dis- abling hindfoot condition can resume relatively normal function. The long-term outcome of patients treated with these techniques re- mains unknown. References 1.Mann RA, Thompson FM: Rupture of the posterior tibial tendon causing flat foot: Surgical treatment. J Bone Joint Surg Am1985;67:556-561. 2.Masterson E, Jagannathan S, Borton D, Stephens MM: Pes planus in child- hood due to tibialis posterior tendon injuries: Treatment by flexor hallucis longus tendon transfer. J Bone Joint Surg Br1994;76:444-446. 3.Fowler AW: Tibialis posterior syn- drome [abstract]. J Bone Joint Surg Br 1955;37:520. 4.Williams R: Chronic non-specific ten- dovaginitis of tibialis posterior. J Bone Joint Surg Br1963;45:542-545. 5.Cracchiolo A III: Evaluation of spring ligament pathology in patients with posterior tibial tendon rupture, tendon transfer, and ligament repair. Foot Ankle Clin1997;2:297-307. 6.Johnson KA: Tibialis posterior tendon rupture. Clin Orthop1983;177:140-147. 7.Johnson KA, Strom DE: Tibialis poste- rior tendon dysfunction. Clin Orthop 1989;239:196-206. 8.Holmes GB Jr, Mann RA: Possible epi- demiological factors associated with rupture of the posterior tibial tendon. Foot Ankle1992;13:70-79. 9.Frey C, Shereff M, Greenidge N: Vas- cularity of the posterior tibial tendon. J Bone Joint Surg Am1990;72:884-888. 10.Stepien M: The sheath and arterial supply of the tendon of the posterior tibialis muscle in man. Folia Morphol (Warsz)1973;32:51-62. 11.Teasdall RD, Johnson KA: Surgical treatment of stage I posterior tibial tendon dysfunction. Foot Ankle Int 1994;15:646-648. 12.Shereff MJ: Treatment of ruptured posterior tibial tendon with direct repair and FDL tenodesis. Foot Ankle Clin1997;2:281-296. 13.Myerson MS, Corrigan J, Thompson F, Schon LC: Tendon transfer combined with calcaneal osteotomy of treatment for posterior tibial tendon insufficien- cy: A radiological investigation. Foot Ankle Int1995;16:712-718. 14.Pomeroy GC, Manoli A II: A new operative approach for flatfoot sec- ondary to posterior tibial tendon insufficiency: A preliminary report. Foot Ankle Int1997;18:206-212. 15.Kitaoka HB, Alexander IJ, Adelaar RS, Nunley JA, Myerson MS, Sanders M: Clinical rating systems for the ankle- hindfoot, midfoot, hallux, and lesser toes. Foot Ankle Int1994;15:349-353. 16.Sangeorzan BJ, Mosca V, Hansen ST Jr: Effect of calcaneal lengthening on rela- tionships among the hindfoot, mid- foot, and forefoot. Foot Ankle1993;14: 136-141. 17.Deland JT, Otis JC, Lee KT, Kenneally SM: Lateral column lengthening with calcaneocuboid fusion: Range of motion in the triple joint complex. Foot Ankle Int1995;16:729-733. 18.Harper MC, Tisdel CL: Talonavicular arthrodesis for the painful adult acquired flatfoot. Foot Ankle Int 1996; 17:658-661. 19.OÕMalley MJ, Deland JT, Lee KT: Selective hindfoot arthrodesis for the treatment of adult acquired flatfoot deformity: An in vitro study. Foot Ankle Int1995;16:411-417. 20.Graves SC, Mann RA, Graves KO: Triple arthrodesis in older adults: Results after long-term follow-up. J Bone Joint Surg Am1993;75:355-362.