Posterior tibial tendon dysfunction: tendon transfers, osteotomies, and lateral column lengthening Nirain A. D’Souza, MD*, Tosca Kinchelow, MD*, and Sheldon Lin, MD† The recognition of Posterior Tibial Tendon Dysfunction (PTTD) as a cause of adult acquired flatfoot has spurred significant evolution of its treatment during the past twenty years. Renewed interest in its pathophysiology and treatment options has led to the creation of several new regimens. Because the treatment of PTTD is relatively new, many of these surgical protocols have relative short-term follow up, hence the controversy regarding the ideal surgical technique for its treatment. This review discusses the current concepts regarding the pathology, diagnosis, and treatment options for this disease. In particular the treatment of Stage 2 PTTD will be discussed. Curr Opin Orthop 2002, 13:81–88 © 2002 Lippincott Williams & Wilkins, Inc. Department of Orthopaedic Surgery, Jersey Medical School, *Resident, Department of Orthopaedic Surgery UMD/NJ-Newark; †Assistant Professor, Department of Orthopaedic Surgery UMD/NJ, Newark, New Jersey, USA. Address reprints and correspondence to S. Lin, MD, 90 Bergen Street DOC 7400, Newark, NJ, USA; e-mail: linss@umdnj.edu Current Opinion in Orthopaedics 2002, 13:81–88 ISSN 1041–9918 © 2002 Lippincott Williams & Wilkins, Inc. Recent advances in the understanding of the pathologic process as well as the biomechanics of PTTD have led to new treatment options. However, it is necessary to review the pertinent anatomy, staging, and nonoperative treatment of PTTD before examining the operative treatment options that are available. Anatomy and function An understanding of anatomy is essential to understanding PTTD. The posterior tibial muscle originates on the posterior tibia and fibula as well as the intermuscular septum. The posterior tibial tendon (PTT) runs in its own fibro-osseous groove behind the medial malleolus. From the medial malleolus, the PTT enters a tenosynovial sheath and divides into multiple insertions including the plantar surfaces of the navicular and medial cuneiform bones. The tendon’s position posterior to the axis of the ankle and medial to the subtalar joint allows it to initiate heel inversion at the conclusion of the foot flat stage of the stance phase. As such, the PTT is a critical component in the complex interaction between the midfoot and hind foot that prepares the entire foot to act as a rigid lever arm. The hindfoot is motivated by the action of the PTT to invert, causing the axes of the talonavicular and calcaneocuboid joints to become nonparallel and creates a rigid midfoot joint. This conformation facilitates the “push-off” required to propel the body through the last aspect of gait. In addition, the axis of the Achilles tendon is shifted medially relative to the subtalar joint with heel inversion and acts to solidly lock the heel in varus further stabilizing the midfoot joints. In contrast to the PTT, which fires during a full weightbearing phase, the peroneus brevis, the primary antagonist is active in the swing phase and has less work to accomplish. Therefore it is smaller in cross sectional area and is approximately 50% as strong [1]. Pathophysiology Although many etiologies have been proposed to explain PTTD, the exact nature and fundamental lesion is still under investigation. Some have pointed to areas of hypovascularity [2] at the level of the medial mallelous. Inflammatory arthropathies as well as direct injection of corticosteroids have also been implicated as causes [3,4]. Mosier et al. [5] provided a histopathologic description of 81 82 Ankle and foot tissue taken during operative reconstruction. The author showed that the underlying pathology is degenerative tendinosis without inflammation. Table 2. Statistical evaluation of pressure and radiographic measurements Mann’s hypothesis has been the general basis regarding the pathophysiology of PTTD [6]. He theorized that a muscular imbalance between tibialis posterior and peroneal brevis combined with a lack of ligamentous support beneath the talonavicular joint, results in a progressive loss of the medial longitudinal arch, a valgus hindfoot, and forefoot abduction. Peak pressure A/P TaloCalcaneal angle Second talo metatarsal Lateral talocalcaneal Lateral talo 1st metatarsal Talonavicular coverage angle Theoretically, an attenuation in the PTT resting length decreases its strength and results in eventual collapse of the medial arch. As foot flat occurs, the PTT is unable to initiate the hindfoot inversion. The antagonist tendon, peroneus brevis, maintains the heel eversion, which in turn keeps the transverse tarsal joints, parallel and supple. Because the hindfoot remains in valgus, the pull of the Achilles tendon is lateral, not medial to the axis of the subtalar joint. This further reinforces the deformity of heel eversion. As heel rise commences, the unlocked midfoot remains flexible, and the static constraints (ie, plantar ligaments) are subjected to the force of body weight as well as the pull of the gastroc-soleus complex. Over time these ligaments weaken and fail, with the loss of the medial arch [7]. In the absence of treatment, the process continues unabated, leading to heel equinovalgus, pes planus, and forefoot abduction [8,9]. The end result is degenerative arthritis in the hindfoot, forefoot, and possibly the ankle joint as well. Several recent studies have attempted to unravel the question regarding the etiology and pathogenesis of PTTD. Mizel et al. [10] analyzed 10 patients who had had a PTT transfer secondary to peroneal nerve injury and did not find valgus hindfoot in any of their patients. The author concluded that, in a PTT-deficient foot, the pathology will not manifest itself if the peroneal brevis function is absent or significantly weakened. Yeap et al. [11••] analyzed 17 patients with a mean follow-up period of 64.4 months after a PTT tendon transfer to regain active ankle dorsiflexion. While 8 (47%) had grade 4 or Table 1. Mean (Standard Deviation) results of pressure and radiographic measurements Normal Peak pressure (kg/cm2) A/P talocalcaneal Angle (deg) Second talo metatarsal (deg) Lateral talocalcaneal (deg) Lateral talo 1st metatarsal (deg) Talonavicular Coverage angle (deg) Flat foot Corrected 8.9 ± 3.6 18.5 ± 2.9 15.0 ± 2.9 24.3 ± 6.1 12.9 ± 8.1 26.0 ± 6.5 23.9 ± 8.8 21.4 ± 7.1 13.1 ± 6.7 39.0 ± 6.2 45.3 ± 10.8 39.9 ± 4.8 −2.1 ± 3.3 11.4 ± 4.9 3.3 ± 6.3 17.9 ± 6.3 38.0 ± 6.5 20.6 ± 7.0 p value Normal vs flat p value Flat vs corrected 0.0064 0.0002 0.0019 0.0248 0.0004 0.0023 0.1590 0.0052 0.0000 0.0718 0.0002 0.0009 better power of eversion, none had a clinical flatfoot on the Harris Beath footprint. In fact, 5 of the 8 had stronger eversion compared with inversion clinically (MRC grading) and by Cybex testing. Therefore, this study questions the relative importance of muscle imbalance in etiology and pathogenesis of PTTD. Some authors suggest a predisposition, such as a pre-existent tendency to flatfoot [12], may be a critical factor in the pathogenesis of PTTD. A foot with pre-existent tendency to flatfoot will tend to pronate more than a normal foot and place additional stress on the PTT. With time and additional stress caused by an extrinsic factor (ie, obesity, seronegative arthropathy), the tendon undergoes degeneration. Diagnosis PTTD occurs more commonly in white, obese, hypertensive women in the fourth to sixth decade [13,14,15]. Myerson noted significant correlation of PTTD patients with a concurrent diagnosis of inflammatory arthropathy [4]. History Early stages are characterized by tenosynovitis. Patients describe an insidious onset of vague activity related pain, unilateral ankle involvement, and swelling along the medial and plantar-medial aspects of the ankle/foot. Patients often complain of fatigue and weakness, uneven shoe wear, and difficulty walking and standing on their toes. As the tendon attenuates, the tenosynovitis and medial pain may or may not resolve. Patients may notice the development of a flat foot (or worsening of previous pes planus). With hind foot valgus, impingement of the lateral malleolus occurs on the calcaneus, causing lateral foot pain. Patients in the late stages of PTTD may exTable 3. Radiographic results (amount of correction) CPA LTMA LTCA TMA TCA TNCA Evans post-op Fusion post-op Evans long term (mean 40.9 mos) Fusion long term (mean 20.3 mos) 5.56°† 9.06° 2.89° 14.5° 9.67° 22.0° 9.37°† 10.89° 2.74° 17.3° 6.68° 26.2° 3.82°* 9.18° 3.27° 12° 4.36° 16.1° 6.44°* 11.5° 3.8° 16.9° 5.25° 23.6° † = p < 0.001; *= p < 0.014 All other measurements show no statistically significant difference between the two groups. Published with permission [36]. Posterior tibial tendon dysfunction D’Souza et al. 83 perience diffuse arthritic pain and stiffness, soft tissue swelling of the hindfoot, and a progressively fixed deformity [14,16,17]. Physical exam Initially the physical exam will reveal little if any sign of PTT dysfunction during evaluation. Only in advanced stages will the classic clinical manifestations be obvious. The exam begins with inspection of the patient’s shoes and any orthoses, noting any uneven and abnormal wear patterns. Then the patient’s unclothed lower extremities should be inspected with the patient fully weight bearing. Any asymmetric swelling and deformity should be noted. With the patient seated, the tendon should then be palpated. Tenderness is most often noted between the distal malleolus and the navicular [15]. If diseased, the tendon may palpable with a gap or thickened (up to 1.5 times normal in chronic PTTD) [14,15]. The motor exam is performed with the foot plantarflexed and everted. Normally patients should be able invert the foot against resistance. Passive range of motion of the foot is assessed, noting if any deformity is flexible or fixed. Depending on the disease stage, associated deformities may be present. Pes planus and hindfoot abduction are assessed by the “too many toes” sign. Hind foot alignment, as well as PTT strength, can be assessed with bilateral and single limb heel-rise [14,15,16,18••]. Bilateral heel-rise is assessed first, to assess if asymmetric heel alignment is present, with the affected side demonstrating decreased inversion. Single limb heel rise, reported to be the most sensitive indicator of PTTD [8,13–15], is performed with the patient fully weight bearing on the affected foot. Normally, 5 to 10 single limb heel rises are possible without difficulty. Depending on the stage of PTT dysfunction, the patient may experience only subjective weakness and not frank failure to initiate heel rise. Hinterman et al. [19] described another valuable test, the first metatarsal rise sign. With the patient fully weight bearing on both feet, the affected foot is rotated, bringing the hindfoot into a varus position. In the PTT deficient patient, the head of the first metatarsal will rise. Staging Johnson and Strom [9] described PTT dysfunction in three clinical stages. The stages correspond with the pathophysiologic progression of the disease. Myerson [17] modified this classification system to include a fourth stage, incorporating the concept of ankle arthrosis. Treatment In nearly all cases of PTTD, a trial of conservative treatment is warranted. For Stage 1 PTTD, a short leg cast is used to control acute pain and swelling. Weight bearing is allowed as the patient’s symptoms abate. The longterm treatment goal is pain relief and prevention of tendon attenuation and subsequent deformity. After the initial casting (1–3 weeks), a custom molded medial posted orthosis is ideal. This orthosis must provide medial support of the longitudinal arch as well as reduction of heel valgus and forefoot abduction. Orthotic treatment is recommended for 3 to 6 months and patients are counseled that they may require this orthosis indefinitely. Despite treatment, some patients will progress to more advanced stages. The use of corticosteroid injection in the treatment carries the risk of tendon rupture and is not recommended. Initially, Stage 2 PTTD is treated similarly to Stage 1. Because the foot is flexible, corrective orthoses are utilized to prevent or correct deformity and control pain. Orthoses are often unable to correct a deformity; therefore one may resort to a medial posted UCBL device [1,20]. If the deformity is severe, an ankle-foot orthosis may be needed. As in Stage 1, Stage 2 is given a threeto six- month trial, before advocating surgical intervention. In Stages 3 and 4, the foot is rigid, and the goal is to provide support and reduce pain. Therefore the foot is braced in in-situ. Although a solid ankle foot orthosis may sometimes prove useful, often an articulated device is better tolerated. In Stage 4 disease a solid device is usually required. Great care must be taken to avoid the complications of skin ulceration because of the rigidity of the deformity. Operative treatment If a trial of conservative treatment fails, patients with Stage 1 PTTD often benefit with PTT exploration. All tenosynovial tissue should be excised, with debridement of degenerated tendon areas and repair of any tears. Significant pathology within the substance of the tendon may require aggressive resection and a tendon transfer to augment the PTT. An FDL transfer to the navicular or medial cuneiform, as well as Achilles lengthening may be incorporated into the operative treatment of Stage 1 PTTD. The treatment of Stage 2 PTTD is still controversial. Isolated FDL transfer, while successful in the short-term period, have failed to demonstrate long-term durability [21]. Failure of isolated FDL transfer has led to the investigation of bony procedures to supplement the FDL transfer. Theoretically they all provide a level of deformity correction that improves the longevity of the tendon transfer. Treatment algorithms of Stage 2 PTTD consists of several distinct protocols. The first consists of medially based procedure that combine a tendon transfer with a medial displacement calcaneal osteotomy. The second concept (based laterally) includes a lateral column lengthening through either the anterior aspect of the calcaneus or calcaneo- cuboid joint, in conjunction 84 Ankle and foot with tendon transfer. A third uses a hybrid-combined approach of medial displacement calcaneal osteotomy in conjunction to the lateral column lengthening. One recent protocol proposes a combined FDL tendon transfer and hind foot fusion. Medial calcaneal slide osteotomy A medial calcaneal slide osteotomy and FDL tendon transfer has been recommended for Stage 2 PTTD. Preliminary studies [22] have reported improved radiographic arch appearance (improvement in lateral first talo-first metatarsal angle of 13° and improvement in arch height) and high patient satisfaction (marked improvement in AOFAS hindfoot score and pain relief) [23]. Recently, Guyton et al. [24••] reported an intermediateterm follow-up review of 26 patients who had undergone FDL transfer and medial displacement calcaneal osteotomy (Fig. 1). With an average 32-month follow-up (range 12–70 months), all patients except three could perform single leg toe rise, a maneuver none could perform preoperatively. Clinically assessed subtalar motion over time remained 81+15% of the contralateral side. Pain relief was judged excellent by 75% and good by 16%; the average AOFAS Hindfoot pain score was 32.5(out of 40). The average functional score for symptom categories of the AOFAS was 26.8(out of 28 possible). Although significant improvements in the radiographic alignment of the foot was noted, only 50% of the patients felt the appearance had noticeably changed and only one (4%) felt the improvement to be significant. The authors concluded the FDL transfer and medial displacement calcaneal osteotomy provides good functional outcome and symptom relief. In addition, the continued ability to perform single heel rise suggests that the procedure is durable and preserves subtalar motion. Still, over 50% fail to notice any improvement in the appearance of their feet. While early clinical studies appear promising, few biomechanical studies exist regarding the effect of medial calcaneal osteotomy upon the foot. It is theorized that the procedure medially displaces both the heel ground contact point, as well as the insertion of the Achilles tendon. This decreases the strain in the medial aspect of the foot and increases the ability of the gastoc-soleus complex to act as an invertor. Recently Nyska et al. [25•] challenged this thinking and hypothesized the success of medial displacement calcaneal osteotomy comes from a shift of the Achilles forces on the hindfoot. Utilizing a dynamic flatfoot model, several distinct different experimental stages were analyzed (key phases: stage 2—intact foot with Achilles loading, stage 4—flatfoot without medial calcaneal displacement osteotomy but with Achilles loading, and stage 6—flatfoot with medial calcaneal displacement osteotomy and with Achilles loading)(Fig. 2). Using radiographic parameters for flatfoot (medial cuneiform height, mean talarfirst metatarsal angle, mean talocalcaneal angle, and mean talonavicular angle), loading of the Achilles tendon increased the deformity of flatfoot, while a medial calcaneal osteotomy significantly decreased the arch flattening effect of this tendon. The author concluded that medial calcaneal osteotomy significantly decreased the arch flattening effect of the Achilles and limits the potential of the deformity. Lee et al. in 46th Annual Meeting of the ORS [26•] introduced the concept of medial displacement osteotomy with posterior distraction and demonstrated signifi- Figure 1. Kaplan-Meier survivorship curve Kaplan-Meier survivorship curve for the FDL transfer augmented by medial displacement osteotomy. Published with permission [8]. Survival analysis of the FDL transfer with calcaneal osteotomy assessed by manual testing for the first year, ability to perform a single leg toe rise thereafter Probability of functioning transfer 1 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 Markers indicate censoring of data 0.1 0 0 1 2 3 Time, yrs 4 5 6 Posterior tibial tendon dysfunction D’Souza et al. 85 Figure 2. Mean heights and ankles Mean cuneiform height, mm 0 —1 —2 —3 —4 —5 —6 A Stage 2 Stage 4 Stage 6 Mean talar-first metatarsal angle, degrees 10 Both the slide and distraction osteotomy significantly corrected the talonavicular joint orientation, but neither procedure significantly corrected talonavicular plantarflexion. In addition there was no difference in talonavicular joint orientation between the slide and distraction slide models. The author concluded that the slide and distraction osteotomies were effective in correcting the flatfoot deformities but were not statistically different. 8 6 4 2 0 B Stage 2 Stage 4 Stage 6 Mean talocalcaneal angle, degrees 3 2 1 0 C Stage 2 Stage 4 Stage 6 Stage 2 Stage 4 Stage 6 8 Mean talonavicular angle, degrees One criticism of the medial calcaneal slide osteotomy and FDL tendon transfer is its inability to completely restore the affected ankle to its pre-morbid clinical condition and radiographic appearance. Previous clinical studies with short-term follow-up review of patients undergoing FDL transfer have shown that pes planus and heel valgus deformity usually persist. Guyton et al. [24] noted only 50% of the patients felt the appearance of their operated foot had noticeably changed and only one felt the improvement to be significant. —1 —2 6 4 2 0 —2 D cantly reduced inversion force requirements for heel rise. This finding was significant because it suggests the distraction technique may be more efficacious than a slide in correcting flatfoot deformity. Lee compared the performance of the slide versus the proposed medial distraction slide osteotomies utilizing a flatfoot model. Twelve fresh specimens were tested using an electronic tracking sensor (FASTRAK, Colchester VT) to monitor the kinematics of the talus, cuboid, calcaneus, and navicular in a dynamically loaded (Achilles, PT, PB, PL) flatfoot deformity model. The slide osteotomy consisted of 1-cm medial displacement of the posterior calcaneus and the distraction was performed by inserting an 8-mm spacer to “distract” the posterior and medialized calcaneal fragment. (A) Mean cuneiform heights. (B) Mean talar-first metatarsal angles. (C) Mean talocalcaneal angles. (D) Mean talonavicular angles. Published with permission [28]. Sammarco and Hockenbury theorized a greater arch correction could be achieved by transferring a stronger muscle. The commonly used FDL is only 28% of relative strength of PTT and only 69% of opposing PB strength [27]. In comparison, the flexor hallucis longus (FHL) is stronger with 50% of the relative strength compared with PTT and exceeds that of opposing PB strength. Sammarco et al. [28••] retrospectively analyzed a series of 19 patients undergoing an FHL tendon transfer and medial calcaneal osteotomy for stage 2 PTTD. While theoretically sound, the authors were unable to demonstrate an improvement of the radiographic appearance of the medial longitudinal arch (no significant difference in lateral first metatarsal angle, calcaneal pitch, and vertical distance to medial cuneiform, or talonavicular coverage). Nevertheless, the clinical outcomes (AOFAS Hindfoot score 62.4 vs 83.6) using this technique were comparable with scores observed in clinical series of FDL tendon transfer and calcaneal osteotomy. Long-term follow-up review is still required to deter- 86 Ankle and foot mine if the clinical outcome of FHL transfer is superior to the FDL transfer with calcaneal displacement. Lateral column lengthening Another proposed technique for Stage 2 PTTD consists of lateral column lengthening through the calcaneocuboid (CC) joint or the proximal anterior process region of the calcaneus (Evan’s like procedure). One recent study analyzed the effect of the lateral column lengthening on the pes planovalgus deformity [29•]. Using a dynamic flatfoot deformity model, the three-dimensional tarsal bone positions were determined using a magnetic tracking system. The arch height decreased 5.3 + 3.5 mm after flatfoot deformity development and increased 3.2 + 3.6 mm after CC fusion. The metatarsotalar alignment and calcaneotalar position improved in adduction and inversion. Calcaneocuboid alignment improved; however, alignment appeared overcorrected in all three planes of motion. In summary, the arch alignment in the toe-off phase of gait in cadaveric feet was improved significantly with CC arthrodesis but was not reduced anatomically. While lateral column lengthening procedures have been shown to reliably restore the medial arch as well as significantly improve forefoot alignment, significant concern exists regarding the CC joint as well as the durability of the correction. Several authors have recommended abandoning the Evan’s like procedure due to concerns of the development of CC arthritis [30,31]. Phillip et al. [30] reported degenerative changes in CC joint in 6 of the 23 feet. Another study by Hinterman [31] reviewed 19 patients who underwent lateral column lengthening by calcaneal osteotomy in conjunction with medial soft-tissue procedures. At an average follow-up review of 23 months, all 19 patients had satisfactory restoration of the medial arch height and correction of forefoot abduction. Two patients (9%) had radiographic signs of CC degeneration and one went on to subsequent arthrodesis after five months. An initial cadaver study [32] demonstrated an increased CC joint pressures after an Evan’s osteotomy with wedge graft. The author concluded the increased CC pressure was too great and recommended an alternative procedure. Recently, Momberger et al. [33•] examined how the lateral column lengthening affected CC joint pressure using an in vitro planovalgus deformity model. Using a Tekscan 6900 sensor (Tekscan Inc, S. Boston, MA), peak pressures were analyzed across the joint under a constant load in normal, planovalgus deformity, and after Evan’s type calcaneal (10-mm lengthening) osteotomy. Peak pressure across the joint increased significantly from the baseline to the flatfoot condition (P < 0.05); however, the change in pressure from the flatfoot to the corrected foot was not significant. In some cases, the peak pressure was actually lower than in the flatfoot condition (Tables 1 and 2) (Fig. 3). The author concluded that calcaneal lengthening through an Evan’s osteotomy does not increase pressure across the CC joint beyond the physiologic loads in the flatfoot model. One recent study attempted to answer the controversy regarding which of these two lateral column lengthening procedures achieved better results for patients with Stage 2 PTTD. Thomas et al. [34•] analyzed 25 patients with 27 feet at one-year. Ten feet underwent Evan’s open wedge osteotomy with tri-cortical iliac crest graft and 17 feet underwent CC distraction arthrodesis. Both groups underwent debridement of PTT with FDL transfer. Radiographic results documented marked improvement in all parameters, with no statistical difference between the two groups. See Table 3. Postoperative AOFAS rating score average 87.9 for the osteotomy and 80.9 for distraction arthrodesis group (also not statistically different). Twenty of 25 in both groups were very satisfied and 96% stated they would have the same surgery again. Complications were observed in 32 patients (34 feet). For the Evan’s group, complications specific to this procedure include two cases of dorsal displacement/subluxation of the anterior process of the calcaneus. For the CC distraction arthrodesis group, 2 non-unions (11.8%), 3 delayed union (17.6%), and 3 graft stress fractures (17.6%) were observed. The author concluded that an Evan’s opening wedge osteotomy and CC distraction arthrodesis offered marked improvement in radiographic parameters and AOFAS score; however, the potential complications were significant for both groups. Of most concern is the high Figure 3. Tekscan graphs Tekscan graphs in the normal, flatfoot, and corrected deformity. Published with permission [21]. Posterior tibial tendon dysfunction D’Souza et al. 87 rate of non-union and delayed union associated with CC distraction arthrodesis. Combined medial calcaneal osteotomy and lateral column lengthening Several centers in the United States have used a combined extra-articular approach of medial calcaneal osteotomy and lateral column lengthening [35]. This concept is unique in its attempts to combine the benefits of the medial displacement osteotomy (ie, the restoration of heel varus and medial realignment of the Achilles to aid heel inversion) with the benefits of lateral column lengthening (ie, the reliable restoration of medial arch height and forefoot abduction). Furthermore, because correction occurs at two sites, less drastic correction are required, thereby decreasing the risk of contiguous arthrosis. Recently, Mosier-Laclair et al. [18••] analyzed the effect of combined medial displacement calcaneal osteotomy and lateral column lengthening in 26 patients with 28 Stage 2 PTTD at 5 years. The patient satisfaction remained high (AOFAS hindfoot score of 90), with a lasting correction of the deformity. Four patients (14%) did demonstrate signs of CC arthrosis and one had talonavicular arthrosis; however, only one patient required subsequent fusion with relief of symptoms. Mosier-Leclair et al. observed the double osteotomy technique provides symptomatic relief and lasting correction of pes planovalgus deformity associated with stage 2 PTTD. They recommended that patients with preoperative signs of calcaneo-cuboid arthritis might not be ideal candidates or that distraction arthrodesis may better serve this subset of patients. Subtalar fusion Another proposed technique for Stage 2 PTTD consists of subtalar fusion in conjunction FDL transfer to the navicular. An isolated subtalar fusion is relatively easy to perform but theoretical concerns for delayed arthrosis at adjacent joints remain. Johnson et al. [36••] reported their retrospective series of Stage 2 PTTD patients (with an average of 27-months follow-up review), undergoing subtalar fusion in conjunction FDL transfer to the navicular as well as spring ligament reconstruction and medial reefing. The authors showed significant improvement in radiographic parameters including an average 6° correction in the AP talo-1st metatarsal angle and 17° improvement in the talonavicular coverage angle. The lateral talo-1st metatarsal angle improved 10° and the medial cuneiform distance improved 6 mm. The AOFAS score was 82 postoperatively. Successful union occurred at 10.1 weeks; however, there was one delayed union. These early results suggest that the FDL transfer with medial soft-tissue reconstruction and subtalar fusion have comparable results with medial calcaneal osteotomy or lateral column lengthening. However, questions concerning the long-term effects on adjacent joints remain to be answered. For Stage 3 PTTD, the standard continues to remain the triple arthrodesis. A rigid Stage 3 PTTD foot, with its various deformities(pesplanovalgus alignment), often has significant arthritis in the hindfoot and midfoot articulations. An anatomic reduction often precedes the arthrodesis because an in-situ fusion carries the risk of future arthrosis at the adjacent joints. Even with properly positioned fusion, there is a risk that valgus deformity will occur. A recent cadaveric study by Song et al. [37••] analyzed the effect of a triple arthrodesis upon the softtissue restraints, specifically the deltoid ligament complex. This cadaveric study suggests that the triple arthrodesis itself causes significant strain on the deltoid ligament complex. Summary The ideal treatment for PTTD dysfunction remains in question. No long-term randomized controlled study exists, analyzing current treatment options. Both medial and laterally based procedures have demonstrated good results in the short term. However the long-term questions concerning the limitations of these have yet to be answered. Regarding medial calcaneal osteotomy, the issue remains its inability to restore the appearance of the medial arch, both clinically and radiographically. Concern regarding subsequent CC joint arthritis after an Evans type procedure is still clinically relevant . Similar criticism exists with calcaneo-cuboid distraction arthrodesis, regarding delayed union and stress fractures. Subtalar fusion remains a viable treatment particularly those patients with some degree of subtalar arthrosis. References and recommended reading Papers of particular interest, published within the annual period of review, have been highlighted as: • Of special interest •• Of outstanding interest 1 Sutherland D: An electromyographic study of the plantar flexors of the ankle in normal walking on the Level. J Bone Joint Surg 1996, 48A:66–71. 2 Frey C, Shereff M, Greendige N: Vascularity of the posterior tibial tendon. J Bone Joint Surg 1990, 72A:884–888. 3 Kettlekamp D, Alexander: Spontaneous Rupture of the Posterior Tibial Tendon. J Bone and Joint Surg 1969, 51A:759–764. 4 Myerson MS, Solomon G, Shereff M: Posterior Tibial Tendon Dysfunction: Its Association with Seronegative Inflammatory disease. Foot Ankle Int 1989, 9:219–215. 5 Mosier SM, Lucas DR, Pomeroy G, Manoli A 2nd: Pathology of the posterior tibial tendon in posterior tibial tendon insufficiency. Foot Ankle Int 1998, 19:520–524. 6 Mann RA, Thompson FM: Rupture of the posterior tibial tendon causing flat foot: surgical treatment. J Bone and Joint Surg [Am] 1985, 67:556–561. 7 Gadzag A, Cracchiolo A: Rupture of the Posterior Tibial Tendon. J Bone Joint Surg 1997, 79A:675–681. 8 Johnson KA: Tibialis posterior tendon rupture. Clin Orthop 1983, 177:140– 147. 88 Ankle and foot 9 Johnson KA, Strom DE: Tibialis posterior tendon dysfunction. Clin Orthop 1989, 239:196–206. 10 Mizel MS, Temple HT, Hecht P, et al: Role of peroneal tendons in the production of the deformed foot with posterior tibial tendon deficiency. Foot Ankle Int 1999, 20:285–289. 11 Yeap JS, Singh D, Birch R: Tibialis posterior tendon dysfunction: a primary or secondary problem? Foot Ankle Int 2001, 22:51–55. •• Seventeen patients observed for a mean of 64.4 months after Tibialis Posterior transfer for active ankle dorsiflexion. In this study PTTD was not an inevitable sequela after PT transfer. The authors suggest there is a predisposition toward flatfeet may be a contributing factor. 12 Dyal CM, Feder J, Deland JT, Thompson FM: Pes planus in patients with posterior tibial tendon insufficiency: asymptomatic versus symptomatic foot. Foot Ankle Int 1997, 18:85–88. 13 Holmes GB, Mann RA: Possible epidemiologic factors associated with rupture of posterior tibial tendon. Foot Ankle Int 1992, 13:70–79. 14 Pomeroy GC, Pike RH, Beals TC, Manoli II A: Acquired flatfoot in adults due to dysfunction of the posterior tibial tendon. J Bone Joint Surg 1999, 81A(8):1173–1182. 15 Churchill RS, Sferra JJ: Posterior tibial tendon insufficiency. Its diagnosis, management and treatment. Am J Orthop 1998, 339–337. 16 Geidman WM, Johnson JE: Posterior tibial tendon dysfunction. J Orthop Sports Phys Ther 2000, 30(2):68–77. 17 Myerson MS: Adult required flatfoot deformity: treatment of dysfunction of the posterior tibial tendon. J Bone Joint Surg [Am] 1996, 78:780–792. Mosier-LaClair S, Pomeroy G, Manoli A: Intermediate follow-up on the double osteotomy and tendon transfer procedure for stage II posterior tibial tendon insufficiency. Foot Ankle Intl 2001, 22:283–293. Five-year follow-up of double osteotomy and tendon transfer in 26 patients and 28 feet. AOFAS score remained 90 at follow up with maintenance of longitudinal arch measurements. Four feet had signs of calcaneo-cuboid arthritis at follow up and one required subsequent fusion. Nyska M, Parks B, Chu I, Myerson M: The contribution of the medial calcaneal osteotomy to the correction of flatfoot deformities. Foot Ankle Int 2001, 22:278–282. Cadaveric study that shows the Achilles tendon loading in a flatfoot model aggravates the deformity. Medial calcaneal osteotomy decreases the arch-flattening effect of the Achilles tendon. 25 • 26 • Lee S, Hubbard C, Young K, et al: Comparison of two calcaneal osteotomies on a flatfoot model. Orthop Res Society, Feb 25–28, 2001: San Francisco, CA. 27 Silver RL, de la Garza J, Rang M: The myth of muscle balance: a study of relative strengths and excursions about the foot and ankle. J Bone Joint Surg 1985, 67B:432. Sammarco GJ, Hockenbury RT: Treatment of stage II posterior tibial tendon dysfunction with flexor hallicus longus transfer and medial displacement calcaneal osteotomy. Foot Ankle Intl 2001, 22(4):305–312. Seventeen patients at 18-month follow-up after FHL transfer and medial calcaneal osteotomy. AOFAS score improved from 62.4/100 to 83.6/100. Despite high patient satisfaction there was no radiographic improvement in the longitudinal arch by radiographic criteria. 28 •• Kitaoka HB, Kura Hideji, Luo ZP, An KN: Calcaneocuboid distraction arthrodesis for posterior tibial tendon dysfunction and flatfoot. Clin Orthop 2000, 381:241–247. Cadaveric study that demonstrates the biomechanical effects of calcaneo-cuboid distraction arthrodesis. Arch alignment in toe-off was significantly improved but was not anatomically recreated. 29 • 30 Phillips GE: A review of elongation of the os calcis for flat feet. J Bone Joint Surg 1983, 65B:15–18. 31 Hinterman B, Valderrabano V, Kundert HP: Lengthening of the lateral column and reconstruction of the medial soft tissue for treatment of acquired flatfoot deformity associated with insufficiency of the posterior tibial tendon. Foot Ankle Int 1999, 20(10):622–629. 32 Cooper P, Norwak MD, Shaer J: Calcaneocuboid joint pressures with lateral column lengthening (Evans) procedure. Foot Ankle Int 1997, 18:199–205. 18 •• 19 Hinterman B, Gachter A: The first metatarsal rise sign: a simple sensitive sign of tibialis posterior dysfunction. Foot Ankle Int 1996, 17:236–241. 20 Chao W, Wapner KL, Lee TH, et al.: Nonoperative management of posterior tibial tendon dysfunction. Foot Ankle Int 1996,17:736–741. 21 Michaelson J, Conti S. Jahss MH: Survivorship analysis of tendon transfer surgery for posterior tibial tendon rupture (abstract). Orthop Trans 1992, 16:30. 22 Myerson MS, Corrigan J, Thompson F, et al.: Tendon transfer combined with calcaneal osteotomy for the treatment of posterior tendon insufficiency: a radiological investigation. Foot Ankle Int 1995, 16:712–718. 23 Myerson MS and Corrigan J: Treatment of posterior tibial tendon dysfunction with flexor digitorum longus tendon transfer and calcaneal osteotomy. Orthopedics 1996, 19:383–388. Guyton GP, Jeng C, Kreiger LE, Mann RA: Flexor digitorum longus transfer and medial displacement calcaneal osteotomy for posterior tibial tendon dysfunction: a middle term clinical follow-up. Foot Ankle Int 2001, 22:627–636. Thirty-two months follow-up review after FDL transfer and medial calcaneal osteotomy. All patients except three could perform a single leg toe raise postoperatively, a maneuver none could perform preoperatively. Subtalar motion was maintained. Radiographic improvement was noted but 50% of patients still felt that their feet had not changed. 24 •• Momberger N, Morgan JM, Bachus KN, West JR: Calcaneocuboid joint pressure after lateral column lengthening in a cavern planovalgus deformity model. Foot Ankle Intl 2000, 21:730–735. Changes in calcaneocuboid joint pressure were statistically insignificant using a dynamic flatfoot model after lateral column lengthening. 33 • Thomas RL, Wells BC, Garrison RL, Prada SA: Preliminary results comparing two methods of lateral column lengthening. Foot Ankle Int 2001, 22:107– 119. While both Evans calcaneal osteotomy and calcaneocuboid distraction arthrodesis are successful, they were still associated with high complication rates. 34 • 35 Pomeroy GC, Manoli II A: A new operative approach for flatfoot secondary to posterior tibial tendon insufficiency: a preliminary report. Foot Ankle Int 1997, 18(4):206–212. Johnson JE, Cohen BE, DiGiovanni BF, Lamdan R: Subtalar arthrodesis with flexor digitorum longus transfer and spring ligament repair for treatment of posterior tibial tendon insufficiency. Foot Ankle Int 2000, 21(9):722–729. Twenty-seven month follow-up review after subtalar fusion and FDL transfer. AOFAS scores remained high. The author’s results compared favorably with lateral column lengthening and may prove more durable. Complications included one delayed union. 36 •• Song S, Lee S, O’Malley M, et al.: Deltoid ligament strain after correction of acquired flatfoot deformity by triple arthrodesis. Foot Ankle Int 2000, 21:573–577. Triple arthrodesis in cadavers was shown to impose increase strain on the deltoid ligament. 37 ••