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FOOT & ANKLE INTERNATIONAL Copyright 2012 by the American Orthopaedic Foot & Ankle Society DOI: 10.3113/FAI.2012.0602 Functional Results of Posterior Tibial Tendon Reconstruction, Calcaneal Ostetomy, and Gastrocnemius Recession Joseph X. Kou, MD; Mamtha Balasubramaniam, MS; Matthew Kippe, MD; Paul T. Fortin, MD Walnut Creek, CA ABSTRACT Level of Evidence: III, Prospective Case Series Background: This study aimed to assess and provide prospective outcome data following reconstruction of Stage II posterior tibial tendon insufficiency, as well as evaluate the effect of reconstruction with gastrocnemius recession on plantarflexion strength. Methods: A prospective evaluation of 24 patients undergoing reconstruction for Stage II posterior tibial tendon insufficiency was granted IRB approval. The reconstructive procedures consisted of a flexor digitorum longus transfer, medial displacement calcaneal osteotomy, lateral column lengthening, and gastrocnemius recession. Patients were asked to complete multiple outcome measures preoperatively, 6 months, 1 year, and 2 years postoperatively. A dynamometer was utilized to evaluate peak torque plantarflexion preoperatively, 6 months, and 1 year postoperatively. Results: In the study, 14 patients completed preoperative surveys, and 23 patients had 2-year followup. Patients were highly satisfied with the results of their surgery. All outcome measures showed statistically significant improvement. Improvement was seen at 6 months, but results continued to improve at the 1-year mark. By the second year, improvement largely reached a plateau. Biodex testing showed no loss of plantarflexion strength after reconstruction and gastrocnemius recession. Conclusion: Reconstruction of the flexible adult acquired flatfoot with FDL transfer, double calcaneal osteotomy, and gastrocnemius recession yielded excellent functional results for the treatment of Stage II posterior tibial tendon insufficiency. Plantarflexion weakness was not found to be a concern. A good functional outcome can be anticipated after the early postoperative period. However, it should be expected to take at least 1 year for maximal benefit. Key Words: Posterior Tibial Tendon; Flatfoot; Gastrocnemius Recession; Calcaneal Osteotomy; Lateral Column Lengthening INTRODUCTION The acquired adult flatfoot deformity (AAFD) is a known entity which causes substantial morbidity. AAFD consists of hindfoot valgus, loss of the medial arch, forefoot abduction, and attenuation of the posteromedial soft tissues, including the posterior tibial tendon (PTT). There are numerous treatment options for the flexible AAFD or Stage II posterior tibial tendon dysfunction as described by Johnson and Strom.11 However, there is currently a paucity of strong, prospective Level I or II studies which support these treatment options. Many studies with Level IV evidence support medializing calcaneal osteotomy with posterior tibial tendon augmentation.7,9,16,17,22,25,28 While good results have been shown with medializing calcaneal osteotomies and PTT augmentation, other bony procedures have been used in conjunction to treat the underlying flatfoot deformity and protect soft-tissue reconstructions. Lateral column lengthening procedures which address peritalar dorsolateral subluxation and medial column stabilization procedures8 which address collapse at the first tarsal-metatarsal joint and forefoot supination from lateral column lengthening, have been utilized in addition to PTT augmentation and medializing calcaneal osteotomies. Studies have shown the ability of these procedures to attain radiographic correction of the deformity,4 but few studies with only Level IV evidence have demonstrated good functional results with double calcaneal osteotomies with PTT augmentation.13,25 Van Der Krans et al.27 has demonstrated with Level II evidence that good results can be obtained with calcaneocuboid distraction arthrodesis, posterior tibial tendon augmentation, and percutaneous Achilles tendon lengthening. However, based on the present literature, insufficient evidence exists to make a specific treatment recommendation for or against the use No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Corresponding Author: Joseph Xavier Kou, MD Muir Orthopaedic Specialists Orthopaedic Surgery 2405 Shadelands Dr. Walnut Creek, CA 94598 E-mail: [email protected] For information on pricing and availability of reprints, email [email protected] or call 410-494-4994 x232. 602 603 Foot & Ankle International/Vol. 33, No. 7/July 2012 FUNCTIONAL RESULTS OF PTT RECONSTRUCTION of double calcaneal osteotomies in the operative management of Stage II AAFD.18 Although the actual role of equinus contracture in AAFD is controversial, it is known to be associated with the disease.26 As such, many AAFD reconstructive procedures include percutaneous lengthening of the Achilles tendon or gastrocnemius recession. Loss of strength after percutaneous Achilles lengthening is a concern.12,24 The use of gastrocnemius recession as an alternative is gaining popularity in the hopes of averting loss of plantarflexion strength. Computer simulations have suggested nearly normal moment-generating characteristics could be restored with gastrocnemius recession compared to significant loss of moment-generating capacity with Achilles lengthening.5 The clinical effect of gastrocnemius recession on plantarflexion strength has yet to be fully addressed. Brodsky et al.3 has shown increased ankle power at push-off after posterior tibial tendon reconstruction; however, only three of the 12 patients had gastrocnemius recessions. Sammarco et al.21 demonstrated an initial decrease in plantarflexion strength after gastrocnemius recession, but with improvement over time. However, the numbers generated in this study were in comparison to the postoperative contralateral extremity and not the preoperative ipsilateral limb. The purpose of this study was two-fold. The first was to prospectively determine the functional results, using validated outcome measures, of PTT reconstruction with FDL transfer to the navicular, medializing calcaneal osteotomy, lateral column lengthening, and gastrocnemius recession. The second was to prospectively determine the effect of these procedures on plantarflexion strength. We hypothesized that there would be an improvement in functional outcome measures following reconstruction and that there would not be a significant loss in plantarflexion strength despite gastrocnemius recession. Procedures that all patients underwent were: 1) gastrocnemius recession through a longitudinal incision along the medial side of the leg at the level of the musculotendinous junction; 2) medial displacement calcaneal osteotomy through the posterior one-third of the calcaneus; 3) lateral column lengthening with approximately 1 cm tricortical iliac crest allograft wedge placed 1 cm proximal to the calcaneocuboid joint (stabilized with one or two 3.5-mm cortical screws); and 4) FDL transfer to the navicular. The PTT was only excised if found to be extremely attenuated and nonfunctional. Twelve patients with first tarsal-metatarsal joint instability and/or arthrosis underwent medial column stabilization (Figures 1 through 4). Associated procedures included two patients who had correction of hallux valgus, and one patient with a fibular stress fracture treated with internal fixation (Figure 2). Postoperative management involved removal of splint and application of a bivalved short leg cast on postoperative day 2. The cast was removed at 1 week postoperatively for wound check and then re-applied, taking care to maintain a plantigrade foot. Patients were made nonweightbearing for a total of 6 weeks, and then placed in a walker boot to progressively weight bear over 1 month. Physical therapy was initiated as soon as weightbearing was allowed. Postoperative orthotics were not used. All patients were treated with coumadin for 1 month postoperatively, maintaining an INR between 2 and 3 for DVT prophylaxis. Patients underwent both pre- and postoperative evaluations. Each evaluation consisted of four outcome measure questionnaires and a measurement of strength with an isokinetic dynamometer. A visual analog foot and ankle scale (VAS) was administered to assess pain, mobility, strength, daily function, overall health, and satisfaction with the results of the surgery on a scale from 0 to 10. The foot and ankle outcome survey (FAOS)19 was utilized to assess pain, symptoms, and ability to function in activities of daily living (ADL). The Rowan foot pain assessment questionnaire (ROFPAQ)20 validated for chronic foot pain, assessed foot pain with an affective, cognitive, and sensory subscale. The SF-1229 was also utilized, which measured both a physical (PCS) as well as a mental component (MCS). Evaluation of plantarflexion strength was accomplished with a Biodex dynamometer. Isokinetic dynamometer testing with the Biodex has been shown to have high test-retest reliability10 and superiority compared to manual muscle testing.1 Peak torque ankle plantarflexion measurements were taken with the knee in full extension and 90 degrees flexion of both the ipsilateral and contralateral extremity. Evaluations were conducted at four time intervals. The first evaluation was administered preoperatively, followed by evaluations at 6 months, 1 year, and 2 years postoperatively. Biodex testing was performed preoperatively, 6 months, and 1 year, postoperatively. Additionally, pre- and postoperative radiographic measurements of hindfoot valgus, talo-first MATERIALS AND METHODS IRB approval was obtained for the study group, which consisted of 24 consecutive patients with Stage II PTT insufficiency treated operatively by one fellowship-trained orthopaedic foot and ankle surgeon between September 2004 and January 2006. Of the 24 patients, seven were male and 17 were female. The average age was 60.9 years with a range of 26 to 81 years of age. All patients had Stage II disease demonstrated by pain along the course of the PTT, weakness during single heel rise, weakness with manual inversion resistance, and flexible deformities involving pronation and abduction at the transverse tarsal joint with valgus angulation of the heel. All patients had failed conservative treatment with shoe modifications, foot orthoses, AFO support, and antiinflammatory medications. Exclusion criteria included neuropathic arthropathy and seropositive arthritis. Copyright 2012 by the American Orthopaedic Foot & Ankle Society 604 KOU ET AL. Foot & Ankle International/Vol. 33, No. 7/July 2012 Fig. 1: Preoperative radiographs of Stage II AAFD with midfoot collapse and fibular stress fracture. Fig. 2: Postoperative radiographs of same patient with double calcaneal osteotomy, first TMT fusion, and fixation of fibular stress fracture. Fig. 3: Preoperative radiographs of stage II AAFD with significant midfoot arthrosis and collapse. metatarsal angle, and talo-navicular coverage angle, presence of calcaneocuboid arthritis, and presence of lateral column pain were recorded. In this study, 24 patients enrolled in the study were able to obtain a preoperative biodex study. Twelve patients followed up for a biodex study at 6 months, and 17 patients followed up for a biodex study at 1-year postop. Fourteen patients completed the four outcome measure surveys preoperatively. Twelve patients completed the outcome measure surveys at 6 months postop, 20 patients completed the outcome measure surveys at 1 year postop, and 23 patients completed the outcome surveys at 2 years postop. No patients were Copyright 2012 by the American Orthopaedic Foot & Ankle Society Foot & Ankle International/Vol. 33, No. 7/July 2012 FUNCTIONAL RESULTS OF PTT RECONSTRUCTION 605 Table 1: Patient Outcome Data Scoring Availability Patient Preop 6 Month 12 Month 24 Month 1 2 3 4 X X X X X X X X X X X 5 X X X X 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X X completely lost to followup. Detailed outcome data availability is summarized in Table 1. Statistical analysis The FAOS, ROFPAQ, SF-12, and VAS were all administered at each of the four time points: preoperatively, 6 months, 1 year, and 2 years postoperatively. At each time point, the responses to the questions in each questionnaire were scored according to the scoring algorithm specified for that questionnaire. This included the creation of subscales based on grouping specific questions within each questionnaire at each time point. Patients’ responses to each of the questions across the four time points were not independent and were, in fact, all highly correlated. Hence each subscale and other responses were analyzed using generalized linear models with time as a nominal predictor and the responses at the preoperative timepoint as the reference level. Multiple comparisons were performed using Bonferroni adjustment. All data were first assessed using numerical and graphical techniques to determine if they met the distributional assumptions of the statistical tests being used to analyze them. Based on this preliminary assessment, parametric, nonparametric or exact statistical tests were used to analyze the data. Continuous variables were summarized using mean ± standard deviation, median, and inter-quartile range (IQR). Categorical variables were summarized using frequencies and percentages. P values less than an alpha of 0.05 (Probability of Type I Error) were considered statistically significant. Fig. 4: Postoperative radiographs of same patient with double calcaneal osteotomy and midfoot fusion. Post-hoc power analysis In this longitudinal study, patients served as their own controls as their post-operative responses were compared to that at pre-op. A power analysis was performed in accordance with the repeated measures study design with one factor (Time) based on one group. Based on this computation, a minimum of 12 subjects when measured repeatedly four times would have achieved 99.5% (approximately 100%) power to test the factor based on a Geisser-Greenhouse Corrected F Test 6,14,15 with a 5% significance level. The actual effect standard deviation was 0.56 (an effect size of 1.60). This study had 24 patients and hence was adequately powered to test the differences between the pre- and postoperative and time points for the various outcomes measured. RESULTS Complications and additional procedures included seven hardware removals, one calf DVT, one wound dehiscence that healed with local wound care, and one delayed wound healing which required 4 weeks of daily dressing changes until healing was achieved. Preoperatively, 18 (75%) patients were found to have subfibular impingement pain (tenderness to palpation distal to the tip of the fibula). No patient had preoperative radiographic evidence of subtalar arthritis. Nineteen (76%) patients had complaints of lateral column pain at 6 months postop. This number dropped to seven (28%) at 1 year and three (12%) by 2 years. No patient had evidence of calcaneocuboid arthritis preoperatively. At 2 years postop, nine patients (36%) had evidence of degenerative changes (defined as joint space narrowing and presence of marginal osteophytes on radiographs) at the calcaneocuboid joint. None of these nine patients had complaints of lateral column pain at latest followup. Medial column stabilization was performed as an adjunct procedure in approximately 50% of the patients. The difference in outcome measures between those who had medial column stabilization procedures and those that did not were compared and not found to be statistically significant (p > 0.05) on any of the outcome measures. Therefore, all conclusions were consistent with those made without taking medial column stabilization into account. For the sake of simplicity and clarity, only results without this stratification were presented in this study. Copyright 2012 by the American Orthopaedic Foot & Ankle Society 606 KOU ET AL. Foot & Ankle International/Vol. 33, No. 7/July 2012 Table 2: VAS Results Preop Mean ± SD, Median (IQR) Pain Mobility Strength Function Overall Health 5.2 4.8 6.5 7.0 4.8 4.6 5.6 6.2 6.4 6.3 ± 2, (1.5) ± 2.0, (2.8) ± 2.3, (3.8) ± 2.1, (3.4) ± 2.4, (3.4) Satisfaction with results of surgery Average at 6-Month Mean ± SD, Median (IQR) Average at 1-year Mean ± SD, Median (IQR) 2.7 ± 2.5, 2.1 (2.8) 7.8 ± 1.8, 8.1 (1.6) 7.3 ± 1.5, 7.6 (1.95) 7.9 ± 2.1, 8 (2.5) 7.6 ± 2.1, 7.9 (3.1) 8.8 ± 1.5, 9.5 (2.5) 1.0 ± 1.1, 0.5 (1.4) 8.6 ± 1.8, 9 (2) 8.1 ± 1.5, 8.2 (2.5) 8.7 ± 1.3, 8.7 (2) 9.0 ± 1.6, 9.8 (1.5) 9.3 ± 1.1, 10 (1) Average at 2-year Mean ± SD, Median (IQR) 1.1 0.5 8.7 9.3 8.1 8.4 8.7 9.5 8.7 9.4 8.9 9.8 ± 1.4, (1.8) ± 1.5, (1.9) ± 1.9, (1.7) ± 1.6, (2.6) ± 1.7, (1.3) ± 1.8, (1.2) Table 3: FAOS, ROFPAQ, and SF-12 Results Preop Mean ± SD, Median (IQR) FAOS pain FAOS symptoms FAOS activities of daily living ROFPAQ sensory ROFPAQ affective ROFPAQ cognitive SF-12 Physical Component 60.3 ± 17.9, 59.7 (19.4) 66.8 ± 22.0, 73.2 (35.7) 65.5 ± 20.2, 67.5 (30) 2.5 ± 0.5, 2.5 (0.6) 3.3 ± 0.7, 3.3 (1.0) 3.1 ± 0.5, 3 (0.6) 35.9 ± 10.8, 32.2 (12.5) 6-Month Mean ± SD, Median (IQR) 70.4 ± 20.5, 63.9 (30.6) 64.9 ± 15.4, 64.3 (16.1) 77.7 ± 17.3, 78.3 (36.7) 2.1 ± 0.7, 1.9 (1.0) 2.5 ± 0.7, 2.4 (1.0) 2.4 ± 0.6, 2.4 (0.8) 41.0 ± 9.7, 39.5 (11.8) 1-Year Mean ± SD, Median (IQR) 86.7 ± 10.5, 87.5 (19.4) 85.8 ± 11.0, 89.3 (16.1) 90.6 ± 8.5, 91.7 (16.7) 1.8 ± 0.3, 1.9 (0.5) 2.0 ± 0.6, 2.0 (0.8) 1.8 ± 0.5, 1.9 (0.7) 49.4 ± 8.9, 48.7 (10.8) 2-Year Mean ± SD, Median (IQR) 87.3 ± 12.3, 91.7 (19.4) 85.6 ± 12.2, 85.7 (17.9) 89.7 ± 10.6, 93.3 (15) 1.7 ± 0.4, 1.7 (0.5) 2.0 ± 0.77, 2.1 (1.1) 1.7 ± 0.7, 1.7 (0.9) 47.2 ± 10.1, 51.3 (15.9) FAOS, foot and ankle outcome survey; ROFPAQ, Rowan foot pain assessment questionnaire. The average preoperative hindfoot valgus of 15.6 degrees improved to 4.1 degrees at 2 years postop. The average preoperative talo-first metatarsal angle of −25.0 degrees corrected to 9.1 degrees at 2 years postop. The average preoperative talo-navicular coverage angle of 27.7 degrees was corrected to 8.7 degrees at 2 years postop. The results of the outcome measure questionnaires (VAS, ROWAN, FAOS, SF-12) are summarized in Tables 2 and 3. The data is organized into graph form in Figures 5 through 8. Statistical data was additionally run to determine if age, the presence of lateral column pain, calcaneocuboid arthritis, the use of a medial column fusion, preoperative distal midfoot collapse, and valgus tibiotalar joint tilt had any significant effect on functional outcome scoring. No statistically significant difference (all p > 0.05) was found to suggest that any of these variables had any significant effect on outcome. Preoperative average plantarflexion strength with a fully extended knee in the operative extremity was found to be Copyright 2012 by the American Orthopaedic Foot & Ankle Society Foot & Ankle International/Vol. 33, No. 7/July 2012 FUNCTIONAL RESULTS OF PTT RECONSTRUCTION Fig. 5: VAS results. Fig. 6: FAOS results. Fig. 7: ROFPAQ results. Copyright 2012 by the American Orthopaedic Foot & Ankle Society 607 608 KOU ET AL. Foot & Ankle International/Vol. 33, No. 7/July 2012 Fig. 8: SF-12 Results (Physical Component). 14.1 Nm, SD = 12.7. At 6 months, this value increased to 15.0 Nm, SD = 6.9 (p = 1.0000). At 1 year, it increased to 21.3 Nm, SD = 11.7 (p = 0.16). Preoperative average plantarflexion strength with the knee flexed 90 degrees in the operative extremity was found to be 14.0 Nm, SD = 9.2. At 6 months, strength increased to 16.4 Nm, SD = 8.3 (p = 1.0000), and then increased to 22.4 Nm, SD = 9.8 (p = 0.0246) after 1 year. For comparison purposes, plantar flexion strength of the contralateral nonoperative extremity (knee flexed and extended) was measured at all three time points, and no statistically significant difference was found between all 3 time points. With a fully extended knee, the preoperative difference between extremities was a 36% weaker operative extremity. At 6 months, the difference increased to 41%, but at 1 year the difference dropped to only 6%. When the knee was flexed 90 degrees, the preoperative difference in strength between extremities was 35% weaker in the operative extremity. By 6 months that difference dropped to 17%, and by 1 year there was only a 4% difference. Biodex plantarflexion strength results are summarized in Table 4 and Figures 9 and 10. DISCUSSION Many retrospective studies have demonstrated that the AAFD can be treated surgically with good results. There are numerous options that the surgeon has to select from when treating the AAFD. Of course, with many options, there are also many opinions on which treatment regimen has the best results. Despite the many options and recommendations in the literature, to our knowledge there is no prospective comparative data in the North American literature to support a specific surgical treatment of the AAFD. This study provides prospective data on the outcome of PTT reconstruction using FDL transfer, medializing calcaneal osteotomy, lateral column lengthening, and gastrocnemius recession. The results of our data demonstrate statistically significant improvement of all outcome measures (VAS, FOAS, ROFAPQ, SF-12) and their subscales at 1 year, with maintenance of that significant improvement at 2 years. Additionally, patients had a high level of satisfaction with the results of the procedure. As a result, we conclude that the treatment regimen described in this study is an excellent option for the treatment of the AAFD. It should be noted that while improvements were seen in the early 6-month postoperative period, many outcome measure results were not statistically significant until the 1year mark. The surgeon and the patient should be aware that a good functional outcome can be seen in the early postoperative period. However, it should be expected to take at least 1 year for the maximum benefit from the procedure to be appreciated. Isokinetic dynamometry evaluation in this study did not demonstrate any statistically significant loss of plantarflexion strength when combining a gastrocnemius recession with PTT reconstruction. In fact, there was a progressive improvement in plantarflexion strength at 1 year when compared to preoperative strength of the ipsilateral extremity. Plantarflexion strength with the leg fully extended would seem to isolate gastrocnemius strength more accurately than with the knee flexed, which relaxes the gastrocnemius. When comparing strength to the contralateral extremity, our 6month results were similar to Sammarco et al.21 in which the early postoperative period saw increased plantarflexion weakness with a fully extended leg when compared to the contralateral extremity. However, similar to Sammarco’s study, at 1 year the situation changed and the operative extremity strength improved. When the knee was flexed, there was no loss in plantarflexion strength postoperatively, and this was likely due to gastrocnemius being relaxed. In Table 4: Biodex Plantarflexion Strength (Nm) results Preop Mean ± SD, Median (IQR) Leg extended operative leg Leg extended contralateral leg Flexed 90 operative leg Flexed 90 contralateral leg 6 months Mean ± SD, Median (IQR) 1 year Mean ± SD, Median (IQR) 14.1 ± 12.7, 9.8 (10.5) 19.2 ± 14.5, 15.2 (16.7) 15.0 ± 6.9, 15.3 (19.2) 21.2 ± 10.3, 23.1 (15.7) 21.3 ± 11.7, 21.8 (15.5) 22.6 ± 11.8, 21.7 (18.7) 14.0 ± 9.2, 11.9 (12.8) 18.9 ± 10.2, 20.0 (17.5) 16.4 ± 8.3, 16.7 (12.1) 19.2 ± 8.3, 18.9 (14.8) 22.4 ± 9.8, 18.9 (12.3) 23.3 ± 13.2, 21.2 (20.9) Copyright 2012 by the American Orthopaedic Foot & Ankle Society Foot & Ankle International/Vol. 33, No. 7/July 2012 FUNCTIONAL RESULTS OF PTT RECONSTRUCTION 609 Fig. 9: Plantarflexion strength of the operative extremity. this study, at 1 year after surgery the operative extremity was 6% weaker than the contralateral extremity, compared to being 36% weaker preoperatively. It should be noted that after 1 year, the ankle was not left weaker compared to preoperative measurements of plantarflexion despite the lengthening from a gastrocnemius recession. Studies have demonstrated increased lateral forefoot pressures after lateral column lengthening procedures.2,23 As a result, there are concerns about lateral column pain and subsequent calcaneocuboid arthritis after lateral column lengthening. Many patients in this study (75%) presented with lateral column pain preoperatively. We believe the source of this pain is from subfibular impingement due to the planovalgus deformity seen in PTTD. The subfibular impingement is relieved after deformity correction through calcaneal osteotomies, but lateral column pain persisted postoperatively on initial followup. In this study there was a 76% incidence of lateral column pain at 6 months postop. However, this number dropped to 28% at 1 year and 12% Fig. 10: Plantarflexion weakness in comparison to contralateral extremity. by 2 years. Although no patient had evidence of calcaneocuboid arthritis preoperatively, at 2 years postop, 36% patients had evidence of degenerative changes at the calcaneocuboid joint. It is interesting to note that none of the patients who developed calcaneocuboid arthritis complained of lateral column pain. Although the patients with postoperative calcaneocuboid arthritis did not have pain 2 years postoperatively, there is reason for concern that they may eventually develop arthritic pain. We believe initial postoperative lateral column pain was from the change in mechanics from the calcaneal osteotomies performed. Preoperative subfibular impingement pain was usually tenderness at the distal tip of the fibula, whereas postoperative lateral column pain manifested as tenderness at the anterior calcaneal process/cuboid/fifth metatarsal base. We theorize that the resultant preferential lateral overload and supination is the cause of initial lateral column pain, but the eventual normalization of motion and gait pattern over 1 to 2 years is why lateral column pain resolved in most patients and was not an issue for 88% of the patients in this study at 2 years. The development of calcaneocuboid arthritis would seem to confirm increased lateral column pressure, but longer-term followup is needed to determine if this increased pressure is clinically relevant in terms of manifesting as chronic pain. Our study design does have limitations. Preoperative data points are incomplete since we were only able to obtain pre-op evaluations on 14 of the 25 patients. We are also missing 2-year followup on one patient. The study size of 25 patients was a sample of convenience, and power analysis was performed ‘post-hoc.’ The FAOS was validated for use in those with rheumatoid arthritis. The use of the FAOS outcome measure, as well as the VAS Copyright 2012 by the American Orthopaedic Foot & Ankle Society 610 KOU ET AL. Foot & Ankle International/Vol. 33, No. 7/July 2012 was not validated specifically to those with PTTD, and is considered a weakness of the use of these outcome measures. Gastrocnemius recession was an adjunct procedure and not done in isolation. As a result, weakness from the procedure may be masked by increased plantarflexion strength from the FDL transfer or less pain. Percutaneous Achilles lengthening is a popular treatment for equinus contracture, but we are unable to compare it to gastrocnemius recession since no Achilles lengthenings were performed in the study. The study design did not include a randomized, non-surgical control group. Also, it is not possible to determine whether there was any benefit to double calcaneal osteotomy over a single osteotomy since no comparisons were made. The adjunct procedure of medial column stabilization could be considered a confounding variable to the results of this study. A complete statistical analysis of this data was performed using medial column stabilization as a binary predictor and no statistically significant differences were found in any of the outcome measures. Although the possibility exists of a Type I error, all conclusions were consistent with those made without taking medial column stabilization into account. For the sake of simplicity and clarity, only results without this stratification were presented in this study. Finally, further long-term followup is needed to evaluate for maintenance of correction and relief of symptoms. 6. 7. 8. 9. 10. 11. 12. 13. 14. CONCLUSION 15. The prospective results of this study make a strong argument for the role of FDL transfer, double calcaneal osteotomy, and gastrocnemius recession in the management of Stage II AAFD. The inclusion of gastrocnemius recession allowed the surgeon to address equinus contracture without the need for concern about plantarflexion weakness after the reconstruction. The surgeon and patient should be aware that a good functional outcome can be anticipated after the early postoperative period, and that further improvements in pain and functionality continue for at least 1 year postoperatively. REFERENCES 16. 17. 18. 19. 20. 1. Andersen, H; Jakobsen, J: A comparative study of isokinetic dynamometry and manual muscle testing of ankle dorsal and plantar flexors and knee extensors and flexors. Eur Neurol. 37:239 – 242, 1997. http://dx.doi.org/10.1159/000117450 2. Benthien, RA; Parks, BG; Guyton, GP; Schon, LC: Lateral column lengthening, flexor digitorum longus transfer, and opening wedge medial cuneiform osteotomy for flexible flatfoot: a biomechanical study. Foot Ankle Int. 28:70 – 77, 2007. http://dx.doi.org/10.3113/FAI.2007.0013 3. 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