Management of the rigid adult acquired flatfoot deformity

The optimal management of the adult acquired flatfoot requires careful assessment of the deformity. Although it is essential to recognize the location and degree of malalignment, it is of equal importance to appreciate whether the deformity is flexible or rigid. For patients undergoing surgery for a flexible flatfoot, various soft tissue procedures and bony osteotomies may be used to restore alignment while preserving joint motion. However, for patients undergoing surgery for a rigid deformity, such procedures are indicated less often, and arthrodesis is usually necessary.     

Operative treatment of the difficult stage 2 adult acquired flatfoot deformity

In the flexible pes planovalgus deformity of stage 2 posterior tibial tendon dysfunction, osteotomies appear to have a significant role in operative management by restoring more normal biomechanics, allowing tendon transfers to function successfully. The options when considering osteotomies for stage 2 disease include lateral column lengthening, medial displacement calcaneal osteotomy, and combined double osteotomy technique. The tight Achilles tendon should be lengthened as well. Lateral column lengthening has been used extensively for treatment of flexible flatfeet. It has been shown clinically and radiographically to address all 3 components of the pes planovalgus deformity present in stage 2 posterior tibial tendon dysfunction. Lateral column lengthening is used in combination with a medial soft tissue rebalancing procedure. The mechanism of action is still speculative but clearly is not owing to tensioning of the plantar fascia as previously thought. Despite the excellent correction of foot posture obtained by use of lateral column lengthening for adult acquired flatfoot, many clinicians have reservations about its use because of reported secondary increases in the calcaneocuboid joint pressures. This increase in pressure has been shown to occur experimentally, increasing the potential risk of calcaneocuboid joint arthrosis. This experimental evidence is supported by Phillips' study of the original Evans procedure, which resulted in a 65% incidence of calcaneocuboid joint arthrosis at 13-year follow-up. Mosier-LaClair et al reported a 14% incidence of calcaneocuboid joint arthritis at 5-year follow-up after double osteotomy for stage 2 posterior tibial tendon dysfunction. This incidence has not been proved true in the remainder of the literature surrounding this procedure and its use for flexible flatfoot. To address the concern regarding potential calcaneocuboid arthrosis secondary to lateral column lengthening, calcaneocuboid joint distraction arthrodesis has been explored as an alternative technique. The results show good initial correction, but the follow-up is extremely limited, and one study reported loss of correction over time. Longer follow-up is needed to determine whether or not this technique would provide the lasting correction seen with the Evans procedure. Calcaneocuboid joint lengthening arthrodesis does result in some limitation of adjacent hindfoot motion. Although this limitation is significantly less compared with talonavicular and subtalar joint fusion, this procedure may result in increased local pressures and arthrosis of the midfoot or hindfoot. For the above-mentioned reasons, longer follow-up studies are needed to determine whether calcaneocuboid joint distraction arthrodesis would prove to be a reliable and safe alternative for lateral column lengthening in the treatment of adult acquired flatfoot. Medial displacement calcaneal osteotomy has been used for correction of the pes planovalgus foot in posterior tibial tendon dysfunction. It has been used extensively for the surgical treatment of flexible flatfoot throughout the literature. Medial displacement osteotomy, in combination with flexor digitorum longus tendon transfer, can address all 3 components of adult acquired flatfoot. It does not recreate the medial longitudinal arch in all patients, however. Although the mechanism of action of medial displacement calcaneal osteotomy is unknown, it has been proved that it is not through the tightening of the plantar fascia in a windlass effect as previously thought. In contrast to lateral column lengthening, however, medial displacement calcaneal osteotomy does address the deforming valgus force of the Achilles tendon. Functionally transferring the insertion of the Achilles tendon medially removes a constant valgus-deforming force. The osteotomy can then act as a double tendon transfer with the flexor digitorum longus tendon to aid in foot inversion. For stage 2 posterior tibial tendon insufficiency, the authors favor the combination double osteotomy technique with a flexor digitorum longus tendon-to-medial cuneiform tendon transfer, débridement or removal of the posterior tibial tendon, and percutaneous heel cord lengthening. Early results were positive at 1.5 years after surgery with respect to maintenance of correction and functional improvement with no evidence of calcaneocuboid arthrosis. More recently, the intermediate 5-year follow-up has been assessed for this combination of procedures, and similar results were found. There was a high rate of patient satisfaction and functional improvement, and surgical correction of the flatfoot deformity was maintained and compared favorably with the contralateral normal foot. Although the intermediate follow-up found a 14% incidence of calcaneocuboid arthrosis, 50% of these patients had preoperative evidence of calcaneocuboid joint arthritis. (ABSTRACT TRUNCATED)     

Posterior calcaneal displacement osteotomy for the adult acquired flatfoot

The posterior calcaneal displacement osteotomy with flexor digitorum longus tendon transfer is an accepted approach to the stage II posterior tibial tendon dysfunction flatfoot. This reconstructive osteotomy provides a viable alternative to isolated hindfoot arthrodesis procedures. Proper patient selection and sound surgical technique ensure favorable postoperative results. Complications, though limited, may include sural neuritis, peroneal tendonitis, undercorrection, and peritalar arthrosis.     

Medial column procedures in the correction of adult acquired flatfoot deformity

AAFD is a complex problem with a wide variety of treatment options. No single procedure or group of procedures can be applied to all patients with AAFD because of the variety of underlying etiology and grades of deformity. As the posture of the foot progresses into hindfoot valgus and forefoot abduction through attenuation of the medial structures of the foot, the medial column begins to change shape. The first ray elevates and the joints of the medial column may begin to collapse. Careful physical examination and review of weight-bearing radiographs determines which patients have an associated forefoot varus deformity that may require correction at the time of flatfoot reconstruction. Correction of an AAFD requires a combination of soft-tissue procedures to restore dynamic inversion power and bony procedures to correct the hindfoot and midfoot malalignments. If after these corrections forefoot varus deformity remains, the surgeon should consider use of a medial column procedure to recreate the “triangle of support” of the foot that Cotton described.5 If the elevation of the medial column is identified to be at the first NC or the first TMT joint, then the joint should be carefully examined for evidence of instability, hypermobility, or arthritic change. If none of these problems exist, then the surgeon can consider use of the joint-sparing Cotton medial cuneiform osteotomy to correct residual forefoot varus. However, if instability, hypermobility, or arthritic change is present, then the surgeon should consider use of an arthrodesis of the involved joint to correct residual forefoot varus. Either procedure provides a safe and predictable correction to the medial column as part of a comprehensive surgical correction of AAFD.     

The use of orthotic devices in adult acquired flatfoot deformity

PTT dysfunction is the most common cause of adult acquired flat foot deformity. The aggressive nonoperative approach has become accepted more widely, in part because of the advances in orthotic and bracing technology and options. Many patients with a PTT dysfunction can be treated effectively with conservative management protocols. The goal of alleviating pain and correcting deformities is being accomplished with the proper application of the wide spectrum of orthotic modalities available today.     

Biotenodesis screw for fixation of FDL transfer in the treatment of adult acquired flatfoot deformity

BACKGROUND: In stage II PTTD, flexor digitorum longus (FDL) tendon transfer with an adjunctive bony procedure is the most common method of surgical correction. This paper presents an alternative method of fixation with a biotenodesis interference screw (Arthrex Biotenodesis Screw System) that allows proper tensioning of the FDL tendon transfer. MATERIALS AND METHODS: We retrospectively reviewed 25 consecutive patients who underwent FDL tendon transfer utilizing a biotenodesis interference screw. Intraoperative stability was noted and any loss of correction was assessed postoperatively. RESULTS: Stable fixation was achieved in 24 of the 25 patients who underwent FDL tendon transfer for PTTD. We were not able to achieve stable fixation in one patient due to improper placement of the bone tunnel. This was recognized intraoperatively and did not affect the final outcome. CONCLUSION: This method is technically easier to perform than the recommended technique by the manufacturer. It can be performed through a slightly smaller incision without disrupting the normal interconnections between flexor hallucis long (FHL) and FDL tendon at the Knot of Henry.     

Effects of surgical correction for the treatment of adult acquired flatfoot deformity: A computational investigation

Computational models of the foot/ankle complex were developed to predict the biomechanical consequences of surgical procedures that correct for Stage II adult acquired flatfoot deformity. Cadaveric leg and foot bony anatomy was captured by CT imaging in neutral flexion and imported to the modeling software. Ligaments were approximated as tension only springs attached at insertion sites. Muscle contraction of the gastrocnemius/soleus complex was simulated through force vectors and desired external loads applied to the model. Ligament stiffnesses were modified to reflect Stage II flatfoot damage, followed by integration of corrective osteotomies—medializing calcaneal osteotomy (MCO) and Evans and calcaneocuboid distraction arthrodesis (CCDA)—to treat flatfoot. Joint angles, tissue strains, calcaneocuboid contact force, and plantar loads were analyzed. The flatfoot simulation demonstrated clinical signs of disease evidenced by degradation of joint alignment. Repair states corrected these joint misalignments with MCO having greatest impact in the hindfoot, and Evans/CCDA having greatest effect in the mid‐ and forefoot. The lateral procedures unevenly strained plantar structures, while offloading the medial forefoot, and increased loading on the lateral forefoot, which was amplified by combining with MCO. The Evans procedure raised calcaneocuboid joint contact force to twice intact levels. Computational results are in agreement with clinical and experimental findings. The model demonstrated potential precursors to such complications as lateral tightness and arthritic development and may thus be useful as a predictor of surgical outcomes. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1047–1054, 2011     

Weight-bearing radiographs and cone-beam computed tomography examinations in adult acquired flatfoot deformity

BackgroundOptimal characterization of Adult acquired flatfoot deformity (AAFD) on two-dimensional radiograph can be challenging. Weightbearing Cone Beam CT (CBCT) may improve characterization of the three-dimensional (3D) structural details of such dynamic deformity. We compared and validated AAFD measurements between weightbearing radiograph and weightbearing CBCT images.Methods20 patients (20 feet, right/left: 15/5, male/female: 12/8, mean age: 52.2) with clinical diagnosis of flexible AAFD were prospectively recruited and underwent weightbearing dorsoplantar (DP) and lateral radiograph as well as weightbearing CBCT. Two foot and ankle surgeons performed AAFD measurements at parasagittal and axial planes (lateral and DP radiographs, respectively). Intra- and Inter-observer reliabilities were calculated by Intraclass correlation (ICC) and Cohen’s kappa. Mean values of weightbearing radiograph and weightbearing CBCT measurements were also compared.ResultsExcept for medial-cuneiform-first-metatarsal-angle, adequate intra-observer reliability (range:0.61?0.96) was observed for weightbearing radiographic measurements. Moderate to very good interobserver reliability between weightbearing radiograph and weightbearing CBCT measurements were observed for the following measurements: Naviculocuneiform-angle (ICC:0.47), Medial-cuneiform-first-metatarsal-gapping (ICC:0.58), cuboid-to-floor-distance (ICC:0.68), calcaneal-inclination-angle(ICC:0.7), axial Talonavicular-coverage-angle(ICC:0.56), axial Talus-first-metatarsal-angle(ICC:0.62). Comparing weightbearing radiograph and weightbearing CBCT images, statistically significant differences in the mean values of parasagittal talus-first-metatarsal-angle, medial-cuneiform-first-metatarsal-angle, medial-cuneiform-to-floor-distance and navicular-to-floor-distance was observed (P < 0.05).ConclusionModerate to very good correlation was observed between certain weightbearing radiograph and weightbearing CBCT measurements, however, significant difference was observed between a number of AAFD measurements, which suggest that 2D radiographic evaluation could potentially underestimate the severity of AAFD, when compared to 3D weightbearing CT assessment.     

Medial column procedures in the acquired flatfoot deformity

This article focuses on the medial column procedures for the treatment of the acquired flatfoot. When performing a medial column procedure alone, in combination with soft tissue reconstruction, or with concomitant lateral bony procedure, the deformity being addressed should include significant abduction or collapse through the talonavicular (TN), naviculocuneiform (NC), or tarsometatarsal (TMT) joints. The procedures covered in this article include arthrodesis of the TN, NC, and metatarsocuneiform (MTC) joints, together or in isloation. Osteotomies of the cuneiforms will also be addressed.     

The effects of adult acquired flatfoot deformity on tibiotalar joint contact characteristics

Changes in the tibiotalar contact characteristics were investigated using eight fresh frozen cadaver ankle specimens to further develop an established model of the acquired flatfoot deformity. The deformity was simulated by sectioning the tendons and ligaments of the ankle and foot that normally support the longitudinal arch. Axial loads of 1,350 N were applied to the foot in a neutral position in both the intact specimen and flatfoot model. The flatfoot condition resulted in significant lateral shifts of 5.28 mm in global contact area and 11.26 mm in the location of peak pressure, and in a small but significant posterior shift of 1.14 mm in global contact area. The flatfoot condition also resulted in a significant, 35%, reduction in contact area. Significant increases in mean pressure, 14%, and peak pressure, 13%, were also found, but were not in proportion to the relatively large decrease in contact area. This suggests a transfer of load off of the talar dome. Increased loading of the lateral facet and fibula are suspected. The lateral shift in the contact region created a local increase in mean contact pressure that may be responsible for long term degenerative changes in patients with this deformity.     

伴严重疼痛的成人平足症的手术治疗

[目的]探讨伴严重疼痛的成人平足症的手术治疗方法。[方法]自2002年8月~2004年10月,手术治疗12例伴严重疼痛的单侧成人平足症患者,男7例,女5例;年龄20~56岁,平均35岁;左足8例,右足4例;病因学:胫后肌腱功能障碍Ⅱ~Ⅲ期6例,先天性平足症3例,神经疾病导致平足症2例,高弓马蹄内翻足术后平足1例。根据M aryland足部评分标准,术前足踝功能可2足,差10足。对每例患者采用个性化手术方案设计,联合应用的术式有足外侧柱延长术、跟骨截骨内移术、关节融合术、胫后肌腱修复术、弹簧韧带紧缩术、趾长屈肌腱转移术等。多数骨性手术均辅以了一种以上相关的软组织手术。术后予以短腿管型石膏将足于内翻跖屈位固定,4~6周后换用短腿后托石膏将足于中立位继续固定4周后拆除外固定,根据骨愈合情况逐渐开始负重训练。[结果]全部病例均获得随访,随访时间16~28个月,平均22个月。M aryland足踝评分:优7足,良3足,可2足,优良率为83.3%。所有患者术后足外形恢复良好,能穿普通鞋。术后X线片测量足弓高度,提示前足外展、后足外翻畸形的特异性角度明显改善(P<0.01)。其中弓高平均增加约9 mm,侧位距跟角减少约17°,前后位距跟角减少约11°,侧位第1跖距角减少约14°,跟骨倾斜角增加约10°,距舟覆盖角减少约6°。[结论]骨性手术结合软组织手术组成的个性化联合术式治疗伴严重疼痛的成人平足症可获得较理想的疗效。     

Functional bracing of the adult acquired flatfoot

This article reviews the current orthotic and pedorthic management of adult acquired flatfoot and associated secondary pathology. Appropriate footwear, footwear modifications, custom foot orthoses, and ankle foot orthoses are highlighted for the treatment of this often seen foot disorder. As this pathology progresses through its various stages, the discussion provides conservative and postoperative alternatives for treatment of even the most affected feet.     

Biomechanics of procedures used in adult flatfoot deformity

A flatfoot deformity can occur secondary to fairly obvious causes, or more subtle and less definable entities. Complicating the situation further, it is likely that the cause of an acquired flatfoot deformity in an adult is multifactorial. This likelihood makes the definition, diagnosis, and appropriate treatment of this condition a daunting task. More research is needed to define further the biomechanics of the foot and to understand the significance of the forces that combine to create flatfoot deformity.     

Calcaneal lengthening: investigation of deformity correction in a cadaver flatfoot model

BACKGROUND: Evans showed that lengthening the lateral column by inserting structural bone graft into the anterior calcaneus could correct abduction and valgus deformity in flatfoot. To better understand the mechanism of correction and the three-dimensional effect of this procedure a cadaver study was done. METHODS: Three cadaver flatfoot models were used. Computed tomographic (CT) scans were made of each specimen before and after lengthening. Data from these scans were used to determine the center of volume of the talus, navicular, cuboid, and calcaneus. The angular and translational motions for each bone were determined. RESULTS: On average, relative to the talus, the navicular moved 18.6 degrees of rotation in adduction, 2.6 degrees of rotation in pronation, and 3.4 degrees in plantarflexion. The average translation was 5.6 mm medial, 0.4 mm posterior, and 1.8 mm plantar. The cuboid moved an average of 24.2 degrees of rotation in adduction and lengthening, 13.9 degrees in pronation, and 1.9 degrees in plantarflexion. The average translation was 9.4 mm medial, 2.6 mm distal, and 1.5 mm plantar. The calcaneus moved an average of 4.4 degrees of rotation in adduction, 0.1 degrees of rotation in eversion, and 1.3 degrees of plantarflexion. The average translation was 3 mm medial and 0.7 mm posterior with no plantar translation. CONCLUSIONS: The mechanism of Evans calcaneal lengthening involves adduction and plantarflexion of the midfoot relative to the hindfoot. The cuboid and navicular appear to move as a unit. The shape of the talar head, axis of the subtalar joint, degree of initial deformity, competence of plantar soft tissues, such as the long plantar ligament, and adequate length of the Achilles tendon are important. Knowing what qualitative three-dimensional changes take place allows a better understanding of the mechanics of the procedure and its possible applications.     

Calcaneal osteotomies for the treatment of adult-acquired flatfoot

Calcaneal osteotomies are useful procedures for the treatment of stage 2 adult-acquired flatfoot. Often combined with adjunctive soft-tissue procedures, the posterior calcaneal displacement osteotomy and Evans procedure provide effective realignment of pes planovalgus deformity. Preoperative evaluation, indications, contraindications, surgical considerations and techniques are discussed.     

Validation of a population of patient‐specific adult acquired flatfoot deformity models

Adult acquired flatfoot deformity (AAFD) is a degenerative disease resulting in malalignment of the mid‐ and hindfoot secondary to posterior tibial tendon dysfunction and increasing implication of ligament pathologies. Despite the complex 3D nature of AAFD, 2D radiographs are still employed to diagnose and stage the disease. Computer modeling techniques allow for accurate 3D recreations of musculoskeletal systems for the investigation of biomechanical factors contributing to disease. Following Institutional Review Board approval, the lower limbs of six diagnosed AAFD sufferers were imaged with MRI, photographs, and X‐ray. Next, a radiologist graded the MRI attenuation of eight soft‐tissues implicated in AAFD. Six patient‐specific rigid‐body models were then created and loaded according to patient weight, graded soft‐tissues, and extrinsic muscles. Model function was validated using clinically relevant kinematic measures in three planes. Agreement varied depending on the measure, with average absolute deviations of <7° for angles and <4 mm for distances. Additionally, the clinically favored AP talonavicular coverage angle, ML talo‐1st metatarsal angle, and ML 1st cuneiform height showed strong correlations of R² = 0.63, 0.75, and 0.85, respectively. Thus, computer modeling offers a promising methodology for the non‐invasive investigation of in vivo kinematic behavior in pathologic feet and, once validated, may further be used to investigate biomechanical parameters that are difficult to measure clinically. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1861–1868, 2013     

Lateral column osteotomy versus subtalar arthroereisis in the correction of Grade IIB adult acquired flatfoot deformity: A clinical and radiological follow-up at 24 months

BackgroundAdult acquired flat foot deformity (AAFD) is a spectrum of conditions which can be progressive if untreated. Surgical correction and restoration of anatomical relationship are often required in the treatment of symptomatic Grade II AAFD after a failed course of conservative treatment. There is a paucity of literature recommending best practice–especially in the adult population. The authors aim to compare radiological and clinical outcomes of two widely employed surgical techniques in the treatment of symptomatic AAFD.MethodsA retrospective study of 76 patients with Grade IIB AAFD and had undergone either lateral column lengthening (LCL) or subtalar arthroereisis (STA) surgical correction of their symptomatic AAFD. Each technique was augmented with both bony osteotomy and soft tissue transfer as determined by on table assessment. Clinical and radiological outcomes were reviewed 24 months after surgery.ResultsLCL and STA groups had comparable radiological outcomes at 24 months after surgery. However, LCL group demonstrated superior American Orthopaedic Foot and Ankle Society (AOFAS) midfoot (90.3 ± 12.6 vs 81.1 ± 20.6, p < 0.001) as well as Visual Analogue Scale (VAS) midfoot scores (0.5 ± 1.6 vs 1.3 ± 2.4, p < 0.001) at 24 months compared to the STA group. STA had a higher complication rate (20.6% vs 4.4%), with all cases complaining of sinus tarsi pain requiring subsequent removal of implant.ConclusionThere is a role for either techniques in the treatment of symptomatic AAFD. LCL whilst more invasive has demonstrated superior outcome scores and lower complication rates at 24 months compared to STA. Patients need to be counselled appropriately to appreciate the benefits of each technique.