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New and Recurrent Ulcerations after Percutaneous Achilles Tendon Lengthening in Transmetatarsal Amputation
New and Recurrent Ulcerations after Percutaneous Achilles Tendon Lengthening in Transmetatarsal Amputation Javier La Fontaine, DPM, MS,1 Damieon Brown, DPM,2 Moffatt Adams, DPM,3 Michael VanPelt, DPM4 The purpose of the study was to review the incidence rate of new and recurrent ulcerations in transmetatarsal amputations after original ulcers healed with percutaneous Achilles’ tendon lengthening as an isolated procedure. We reviewed 35 charts from period of January 1995 to March 2007, and 28 were included for the final review. Twenty-four ulcers were grade 1A, 2 were 0A and 1B, and 1 was 1C using the University of Texas Grading System. Time to heal of ulceration post-TAL was 9.4 weeks (range 3-72 weeks). For statistical analysis, we used binomial distribution for dichotomous variables. Results demonstrated 4 limbs did not heal, 10 patients had an ulcer recurrence (p⬍0.001), and 6 developed new ulcers. Of the 28 patients in which TAL was performed, 16 developed new neuropathic ulcers (including recurrent ulcers; p⫽0.0099). High recurrence and new ulcers formation exist after TAL in patients with an unbalanced metatarsal amputation, and extrinsic/ intrinsic factors may need to be addressed to prevent recurrence. Level of Clinical Evidence: 4 ( The Journal of Foot & Ankle Surgery 47(3):225–229, 2008) Key Words: tendo-achilles lengthening, ulcer, equinus, transmetatarsal amputation
P lantar neuropathic ulceration is a common complication in people with diabetes. Of all patients with diabetes, 15% will develop ulceration during their lifetime (1). Eighty-five percent of amputations performed in the diabetic population are preceded by ulceration (2). Thus, prevention or prompt healing of an ulcer will further prevent amputation. Offloading is the most effective treatment for neuropathic ulcers. Over the years, the gold standard for offloading a neuropathic ulcer has been the total contact cast, but bed rest, wheelchair, patellar-tendon brace can also be used (3, 4). The total contact cast is expensive, labor intensive, and is fraught with potential complica-
Address correspondence to: Javier La Fontaine, DPM, MS, University of Texas Health Science Center, Department of Orthopedics, 7703 Floyd Curl Dr. MSC7776, San Antonio, TX 78229. E-mail: lafontaine@uthscsa. edu. 1 Director, Podiatry Residency Program, Department of Orthopedics, Podiatry Division, University of Texas Health Science Center, San Antonio, TX. 2 Private Practice, Advanced Foot Care Center, Chattanooga, TN. 3 PGY-3, Department of Orthopedics, Podiatry Division, University of Texas Health Science Center, San Antonio, TX. 4 Assistant Professor, Dept. of Orthopaedic Surgery, University of Texas Southwestern Medical Center at Dallas, Dallas, TX. Financial Disclosure: None reported Conflicts of Interest: None reported Copyright © 2008 by the American College of Foot and Ankle Surgeons 1067-2516/08/4703-0010$34.00/0 doi:10.1053/j.jfas.2008.01.006
tions (5). Lin et al. was the first to combine the effectiveness of Achilles’ tendon lengthening (TAL) and total contact cast in the treatment of plantar ulcerations (6). Armstrong et al. (7, 8) showed retrospectively that there is a decreased plantar peak pressures in the forefoot before and after TAL. Also, Aronow and colleagues demonstrated that forefoot and midfoot pressures increase with contracture of the gastrocnemius–soleus complex (9). It has been studied under electron microscopy that an abnormal collagenous organization in diabetic Achilles’ tendon as well as non-enzymatic glycosylation effects on tendon and joint capsule decreases joint range of motion, increases contractures and peak plantar pressures and, therefore, lead to ankle equinus and ulceration respectively (10). Achilles’ tendon lengthening assist in healing in 80% of the ulcers treated (11). Mueller in 2003 demonstrated a high recurrence rate of ulceration after treatment with total contact cast alone (81%) when compared with total contact cast and TAL (38%) at 2 years follow-up (12). However, the intended goal was to reach 10° of dorsiflexion at the time of the intervention. Although TAL may be an effective way to assist healing and prevent recurrence of ulceration, a substantial ankle weakness, and reductions in plantar flexor torque has persisted beyond 8 months after surgery (13). In the same study, forefoot plantar pressure returned to high levels at 8 months as well. VOLUME 47, NUMBER 3, MAY/JUNE 2008
225
TAL can be performed, but not without complications (11). Heel ulcers are associated with ankle dorsiflexion of ⬎15° post-operative indicating a calcaneus gait (11). Other complications were also observed such as tendon rupture (10%), recurrence with ankle dorsiflexion ⬍10°, and Charcot arthropathy (4%). There is only one study addressing TAL in transmetatarsal amputations (TMA). In 1993, Barry et al. performed 33 TAL for the treatment of chronic ulcerations after TMA (14). The procedure achieved 91% healing rate and failed to heal 6% of the ulcers. However, no assessment of recurrent ulcerations after the procedure was done. In 1949, McKittrick et al (15) proposed the procedure as foot salvage for diabetic patients with infection or gangrene. However, the benefit of performing a partial foot amputation is well established in the medical literature. The more proximal the amputation, the greater the energy cost of ambulation and the lower the level of subsequent independent functioning (16). Inadequate blood flow, smoking history, and end-stage renal disease are risk factors for poor outcome following a TMA (17-19). Prompt healing of TMA is associated with good ambulatory capacity (19). In a retrospective study by Blume et al., initial healing of TMA (62/91) correlated significantly with the ability to ambulate and overall limb salvage. Also, tendon balancing procedures have been suggested to reestablish a plantigrade stump (20). Recurrent ulcerations have been well documented following partial foot amputations and transmetatarsal amputations (14, 21, 22). Kelly et al., demonstrated the peak plantar pressures of the transmetatarsal amputation side were 16% higher than those of the contralateral side but the difference was not statistically significant. In addition, there was no significant difference in peak plantar pressures in subjects with diabetes mellitus and transmetatarsal amputation compared with control subjects. We feel that the outcomes of this procedure are related to variation in the evaluation of equinus, the subjectivity in determining intraoperative amount of dorsiflexion necessary, and pedal deformities associated to the ulcers. The aim of the study was to investigate the incidence rate of new and recurrent ulcerations after percutaneous Achiilles’ tendon lengthening as an isolated procedure once the target ulcers healed.
Research Design and Methods We reviewed medical records from a period of January1995 to March 2007 at the University of Texas Health Science Center at San Antonio who underwent TAL for plantar ulcerations. Thirty-five medical records were reviewed from subjects who had undergone TAL for neuropathic ulcers after transmetatarsal amputation (TMA). 226
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Twenty-eight charts were included for the final review and data collected in 28 lower extremities. Seven charts were excluded because of deep infected ulcers, previous TAL, TAL performed for other purpose other than plantar neuropathic ulcers, TAL performed concomitantly with other procedures, inability for subjects to return to prescribed shoewear, and osseous equinus abnormal metatarsal parabola, and overgrowth of bone leading to ulceration. Radiographs were reviewed to assess structural deformities. Subjects included in this review had plantar ulcers in TMA, gastroc-soleus equinus, peripheral neuropathy, and no vascular disease to contraindicate the procedure. Gastro-soleus equinus was assessed clinically by fully extending the knee, maximally dorsiflexing the ankle, and flexing the knee. Gastroc-soleus equinus was diagnosed when the ankle did not dorsiflex beyond perpendicular in relation to the fibula when the knee was flexed, and the foot in neutral position (23). Evaluation of equinus was performed by the surgeon during the preoperative visit. Procedures were performed by multiple surgeons. Peripheral neuropathy was confirmed using a biothesiometer, 5.07g monofilament following the criteria suggested by Birke and Sims, 1986 (24). In those patients who had an absent pulse, non-invasive vascular assessment was performed prior to the procedure. All those with an ankle-brachial index of ⬎0.80 were considered candidate for the procedure, and non-healing ulcers with equinus. Twenty-one ulcers were located in the distal transmetatarsal stump, and 7 in the plantarlateral midfoot (not related to Charcot deformity). The procedure was performed with aseptic techniques, under general or local anesthesia. The Achilles’ tendon was surgically lengthened by different surgeons as described by Hoke (25). Three percutaneous incisions were performed approximately 3 cm apart from each one, and careful continuous dorsiflexion of the foot was applied until it passed perpendicular in relation to the fibula. No adjunct procedures were performed. Incisions were approximated with sutures or steri-strips. All subjects were allowed to partially bear weight after surgery with removable cast boot or total contact cast until ulcer healed. All patients were prescribed and returned to extra-depth shoes with prescribed insoles. For statistical analysis, we used binomial distribution for dichotomous variables because the data was collected based on the possibility of whether a new or recurrent ulceration occurred. Based on previous data from Holstein’s and Lin’s study (6, 11), we expected that 20% of subjects will develop a new and recurrent ulcer. For the analysis, a new ulcer was defined as an ulcer that appeared in another location once the target ulcer healed. A recurrent ulcer was defined as an ulcer that appeared once the target ulcer healed. A posteriori power analysis indicated that with a fixed number of 28 subjects, and an expected proportion of .20 (that is, 20% of subjects will develop a new ulcer) at a 90%
Table 1
Mann-Whitney test
Age by Recurrence
no yes Median difference 95.1% CI Mann-Whitney’s statistic Z statistic 2-tailed p
Table 2 n
Rank sum
Mean rank
U
18 262.5 14.58 88.5 10 143.5 14.35 91.5 0.5 -12.0 to 11.0 (normal approximation) 88.5 0.07 0.9426 (normal approximation, corrected for ties)
Fisher exact test
Gender
Female Male Total Difference of proportions 95% CI 2-tailed p
Recurrence
Total
no
yes
4 14 18 -0.200
4 6 10
8 20 28
-0.600 to 0.200 (normal approximation) 0.5679 (exact, double 1-tailed p)
Table 3
confidence interval, statistical significance can be detected. For the analysis, we used an alpha level of 0.05. Statistical analysis was performed by one of the co-investigators (MA), using Analyse-it® for Microsoft Excel (version 2.03; Microsoft Corporation, Redmond, WA).
Test Title Null Hypothesis n
Recurrence
Results The outcome of the study was to investigate the incidence rate of new and recurrent ulcerations in TMA after the original ulcers healed with percutaneous Achilles’ tendon lengthening as an isolated procedure. A target ulcer is the ulcer which the intervention was performed in order to heal. A new ulcer was defined as an ulcer that appeared in another location once the target ulcer healed. A recurrent ulcer was defined as an ulcer that appeared once the target ulcer healed. Median age of subjects was 51 years (range 24-72 years). All subjects were type 2 diabetic patients. There were 20 males and 8 females. All procedures were unilateral. Twenty-four ulcers were grade 1A, 2 were 0A, 1B and 1 was 1C using the UT wound classification system (26). The one ulcer that was considered 1B (infected) was prescribed oral antibiotics prior to the procedure. The two ulcers that were classified as 0A were included in the study because at the time of the procedure they were 0A, however, the ulcer continue to recur once the subjects returned to prescription shoes. Twenty-four ulcers healed, and four patients did not heal the ulcers. The 2 ulcers classified as 0A, were considered healed since they were no longer areas of impending cutaneous compromise. The 4 ulcers which did not heal were included in the study since the final outcomes were to assess new and recurrent ulcers after the intervention. Mean time to heal the ulcers after TAL was 9.4 weeks (range 3-72 weeks). To evaluate association between age and recurrence we used Mann Whitney test for parametric measurement. No statistical significance was found (Table 1). To evaluate association between gender and recurrence we used Fisher exact test. No statistical significance was
Binomial Test Recurrence after TAL Recurrence: no ⫽ 0.2 28
Total Hypothesized proportion Proportion 95% CI 2-tailed p
Total
no
yes
18 0.200
10
28
0.643 0.441 to 0.814 (exact) ⬍0.0001 (exact, double 1-tailed p)
Table 4 Test Title Null Hypothesis n
Binomial test New ulcers after TAL New Ulcer: no ⫽ 0.2 28 New Ulcer
Total Hypothesized proportion Proportion 95% CI 2-tailed p
Total
no
yes
12 0.200
16
28
0.429 0.245 to 0.628 (exact) 0.0099 (exact, double 1-tailed p)
found (Table 2). Ten limbs had an ulcer recurrence (p⬍0.0001) [Table 3], and 6 developed new ulcers in different foot location. Five new ulcers were located at the heel, and 1 sub-5th metatarsal stump. Therefore, of the 28 limbs in which TAL was performed, a total of 16 limbs developed new ulcers at the time of follow up, including all recurrent ulcers (p⬍0.0099) [Table 4]. Of the 16 new ulcers, 5 were heel ulcers (p⬍0.0003) [Table 5]. The incidence of recurrent ulcerations after initially healing following TAL VOLUME 47, NUMBER 3, MAY/JUNE 2008
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Table 5 Test Title Null Hypothesis n
Binomial test Heel ulcers after TAL Heel ulcer: no ⫽ 0.47 28 Heel ulcer
Total Hypothesized proportion Proportion 95% CI 2-tailed p
Total
no
yes
23 0.470
5
28
0.821 0.631 to 0.939 (exact) 0.0003 (exact, double 1-tailed p)
for the treatment of neuropathic foot ulceration was 35% (10/28). The incidence of new ulcerations after initially healing following TAL for the treatment of neuropathic foot ulceration was 21% (6/28). There were no complications such as tendon ruptures, infections, or amputations associated with the TAL. Discussion The role of gastroc-soleus equinus in the development of foot ulceration has been studied extensively. The Achilles tendon in diabetic patients has increased density of collagen fibrils, abnormal fibril morphology with disorganized collagenous fibers, and therefore, increased stiffness and plantar pressures (10). Several studies have demonstrated that percutaneous TAL has an effect in peak plantar pressure and ankle range of motion. Armstrong and colleagues showed in a retrospective study that peak plantar pressure decreases under the forefoot up to 8 weeks after TAL (7, 8). Maluf et al. (13) showed that a temporary reduction in peak forefoot pressure is noticed on those subjects that TAL is performed, but at 8 months, forefoot pressure and plantarflexory moment and power increased significantly. Their results suggest that TAL causes a temporary reduction in forefoot pressure primarily by reducing plantarflexory power during gait. The authors attributed the late increase in forefoot pressure to the plantarflexory muscles’ regaining strength after TAL. Although our study did not measure peak plantar pressures or muscle power, these observations may explain the high number of new ulcers in our study at an average of 2 years follow up. Recurrence of forefoot ulcerations after TAL ranges from 19% to 38% (6, 12). Mueller in 2003 demonstrated in a randomized clinical trial that TAL prevents recurrence of ulcers when compared to the group which did not undergo TAL. The study involved sixty-four subjects randomized 228
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into two treatment groups, total contact cast group and total contact with TAL group (12). At the time of the two-year follow-up, twenty-one (81%) of the twenty-six patients in the total-contact cast group and ten (38%) of the twenty-six patients in the TAL group had ulcer recurrence. Holstein et al. (11) demonstrated in his study a high incidence of recurrence and heel ulcers. In his retrospective review, of 68 patients and 75 ulcers, they noticed healing of the ulcers was obtained in 68 of 75 feet (91%). At a median follow-up of 12 months, a healing rate of 60 of 75 ulcers was accomplished (80%). Acute transfer ulcers to the heel occurred in 47% of patients and they were associated with excessive dorsiflexion (⬎15°) in the neuropathic heels. The authors concluded that lengthening of the Achilles tendon is effective in healing plantar neuropathic ulceration, but the procedure should be performed only in a setting that can manage complication and new ulcers. Our study showed similar findings as Holstein and Mueller. Ten of the 28 patients (35%) treated with TAL developed recurrence by the time of follow up. Also, six ulcers occurred in a new area not related to the target ulcer (5 in the heel, and 1 in the forefoot). A total of sixteen new ulcers at a follow-up of 2.4 years occurred in our study which represents findings similar to previous studies. Many clinicians agree that equinus may play a limited role in ulcer development. Orendurff (27) studied the relationship of equinus in peak plantar pressure in 27 subjects. Simple linear regression showed that the relationship between equinus and peak forefoot pressure was significant (p ⬍ 0.0471), but that only a small portion of the variance was accounted for (R(2) ⫽ 0.149). They concluded that equinus has only a limited role in causing high forefoot pressure. We also agree with Orendurff that equinus has only a limited effect on forefoot pressure. Also, Holstein’s study had seven ulcers which did not heal (10%) to 6 of which he attributed digital deformities as the primary cause. Although we did not analyze other risk factors, we concur with Holstein’s study. In our study, four ulcers did not heal, and of the 5 heel ulcers, 2 occurred in the subjects with 0a ulcers as the target ulcer. Our study has its limitations. First, we did not measure preoperative and post-operative dorsiflexion, which is an important factor when investigating the association between dorsiflexion and the development of heel ulcers after the procedure. Secondly, a true correlation between risks factors that may lead to recurrent or new ulcer formation after TAL could not be determined. Although we feel that variables such as age, gender, duration of ulcer, control of diabetes, UT grade may play a role in healing the ulcer, the authors failed to analyze those variables. We feel, however, that these variables may not play a role in developing recurrence or new ulcer formation. Our study does confirm that in a clinical setting
where TAL is performed commonly as the treatment of ulcers, careful monitoring should continue. We are able to conclude that a high recurrence and new ulcer formation exist after TAL in a clinical setting, and other extrinsic and intrinsic factors may need to be addressed. TAL should be performed for treatment of neuropathic ulcerations as an adjunctive procedure to appropriate shoegear, deformity correction, and pedal education.
13.
14.
References
15.
1. Boulton AJ. The diabetic foot: a global view. Diabetes Metab Res Rev 16 Suppl 1:S2–5, 2000. 2. Reiber GE, Boyko EJ, Smith DG: Lower extremity foot ulcers and amputation in diabetes., in MI Harris, CC Cowie, MP Stern, EJ Boyko, GE Reiber, PH Bennett (eds): Diabetes in America. Washington, D.C., US Government Printing Office, 1995. 3. Armstrong DG, Nguyen HC, Lavery LA, van Schie CH, Boulton AJ, Harkless LB. Off-loading the diabetic foot wound: a randomized clinical trial. Diabetes Care 24:1019 –1022, 2001. 4. Shaw JE, Hsi WL, Ulbrecht JS, Norkitis A, Becker MB, Cavanagh PR. The mechanism of plantar unloading in total contact casts: implications for design and clinical use. Foot Ankle Int 18:809 – 817, 1997. 5. Guyton GP. An analysis of iatrogenic complications from the total contact cast. Foot Ankle Int 26:903–907, 2005. 6. Lin SS, Lee TH, Wapner KL. Plantar forefoot ulceration with equinus deformity of the ankle in diabetic patients: the effect of tendo-Achilles lengthening and total contact casting. Orthopedics 19:465– 475, 1996. 7. Armstrong DG, Stacpoole-Shea S, Nguyen H, Harkless LB. Lengthening of the Achilles tendon in diabetic patients who are at high risk for ulceration of the foot. J Bone Joint Surg Am 81:535–538, 1999. 8. Armstrong DG, Stacpoole-Shea S, Nguyen H, Harkless LB. Lengthening of the achilles tendon in diabetic patients. J Bone Joint Surg Am 82-A:1510, 2000. 9. Aronow MS, Diaz-Doran V, Sullivan RJ, Adams DJ. The effect of triceps surae contracture force on plantar foot pressure distribution. Foot Ankle Int 27:43–52, 2006. 10. Grant WP, Sullivan R, Sonenshine DE, Adam M, Slusser JH, Carson KA, Vinik AI. Electron microscopic investigation of the effects of diabetes mellitus on the Achilles tendon. J Foot Ankle Surg 36:272– 278; discussion 330, 1997. 11. Holstein P, Lohmann M, Bitsch M, Jorgensen B. Achilles tendon lengthening, the panacea for plantar forefoot ulceration? Diabetes Metab Res Rev 20 Suppl 1:S37– 40, 2004. 12. Mueller MJ, Sinacore DR, Hastings MK, Strube MJ, Johnson JE. Effect
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of Achilles tendon lengthening on neuropathic plantar ulcers. A randomized clinical trial. J Bone Joint Surg Am 85-A:1436 –1445, 2003. Maluf KS, Mueller MJ, Strube MJ, Engsberg JR, Johnson JE. Tendon Achilles lengthening for the treatment of neuropathic ulcers causes a temporary reduction in forefoot pressure associated with changes in plantar flexor power rather than ankle motion during gait. J Biomech 37:897–906, 2004. Barry DC, Sabacinski KA, Habershaw GM, Giurini JM, Chrzan JS. Tendo Achillis procedures for chronic ulcerations in diabetic patients with transmetatarsal amputations. J Am Podiatr Med Assoc 83:96 – 100, 1993. McKittrick LS, McKittrick JB, Risley TS. Transmetatarsal Amputation for Infection or Gangrene in Patients with Diabetes Mellitus. Ann Surg 130:826 – 840, 1949. Waters RL, Perry J, Antonelli D, Hislop H. Energy cost of walking of amputees: the influence of level of amputation. J Bone Joint Surg Am 58:42– 46, 1976. La Fontaine J, Reyzelman A, Rothenberg G, Husain K, Harkless LB. The role of revascularization in transmetatarsal amputations. J Am Podiatr Med Assoc 91:533–535, 2001. Nguyen TH, Gordon IL, Whalen D, Wilson SE. Transmetatarsal amputation: predictors of healing. Am Surg 72:973–977, 2006. Blume P, Salonga C, Garbalosa J, Pierre-Paul D, Key J, Gahtan V, Sumpio BE. Predictors for the healing of transmetatarsal amputations: retrospective study of 91 amputations. Vascular 15:126 –133, 2007. Schweinberger MH, Roukis TS. Balancing of the transmetatarsal amputation with peroneus brevis to peroneus longus tendon transfer. J Foot Ankle Surg 46:510 –514, 2007. Dalla Paola L, Faglia E, Caminiti M, Clerici G, Ninkovic S, Deanesi V. Ulcer recurrence following first ray amputation in diabetic patients: a cohort prospective study. Diabetes Care 26:1874 –1878, 2003. Rosenblum BI, Freeman DV. Surgical revision of the problematic transmetatarsal amputation. J Am Podiatr Med Assoc 83:91–95, 1993. Nishimoto GS, Attinger CE, Cooper PS. Lengthening the Achilles tendon for the treatment of diabetic plantar forefoot ulceration. Surg Clin North Am 83:707–726, 2003. Birke JA, Sims DS. Plantar sensory threshold in the ulcerative foot. Lepr Rev 57:261–267, 1986. Hoke M. An operation for stabilizing paralytic feet. American Journal of Orthopedic Surgery 3:484 –507, 1921. Armstrong DG, Lavery LA, Harkless LB. Validation of a diabetic wound classification system. The contribution of depth, infection, and ischemia to risk of amputation. Diabetes Care 21:855– 859, 1998. Orendurff MS, Rohr ES, Sangeorzan BJ, Weaver K, Czerniecki JM. An equinus deformity of the ankle accounts for only a small amount of the increased forefoot plantar pressure in patients with diabetes. J Bone Joint Surg Br 88:65– 68, 2006.
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P lantar neuropathic ulceration is a common complication in people with diabetes. Of all patients with diabetes, 15% will develop ulceration during their lifetime (1). Eighty-five percent of amputations performed in the diabetic population are preceded by ulceration (2). Thus, prevention or prompt healing of an ulcer will further prevent amputation. Offloading is the most effective treatment for neuropathic ulcers. Over the years, the gold standard for offloading a neuropathic ulcer has been the total contact cast, but bed rest, wheelchair, patellar-tendon brace can also be used (3, 4). The total contact cast is expensive, labor intensive, and is fraught with potential complica-
Address correspondence to: Javier La Fontaine, DPM, MS, University of Texas Health Science Center, Department of Orthopedics, 7703 Floyd Curl Dr. MSC7776, San Antonio, TX 78229. E-mail: lafontaine@uthscsa. edu. 1 Director, Podiatry Residency Program, Department of Orthopedics, Podiatry Division, University of Texas Health Science Center, San Antonio, TX. 2 Private Practice, Advanced Foot Care Center, Chattanooga, TN. 3 PGY-3, Department of Orthopedics, Podiatry Division, University of Texas Health Science Center, San Antonio, TX. 4 Assistant Professor, Dept. of Orthopaedic Surgery, University of Texas Southwestern Medical Center at Dallas, Dallas, TX. Financial Disclosure: None reported Conflicts of Interest: None reported Copyright © 2008 by the American College of Foot and Ankle Surgeons 1067-2516/08/4703-0010$34.00/0 doi:10.1053/j.jfas.2008.01.006
tions (5). Lin et al. was the first to combine the effectiveness of Achilles’ tendon lengthening (TAL) and total contact cast in the treatment of plantar ulcerations (6). Armstrong et al. (7, 8) showed retrospectively that there is a decreased plantar peak pressures in the forefoot before and after TAL. Also, Aronow and colleagues demonstrated that forefoot and midfoot pressures increase with contracture of the gastrocnemius–soleus complex (9). It has been studied under electron microscopy that an abnormal collagenous organization in diabetic Achilles’ tendon as well as non-enzymatic glycosylation effects on tendon and joint capsule decreases joint range of motion, increases contractures and peak plantar pressures and, therefore, lead to ankle equinus and ulceration respectively (10). Achilles’ tendon lengthening assist in healing in 80% of the ulcers treated (11). Mueller in 2003 demonstrated a high recurrence rate of ulceration after treatment with total contact cast alone (81%) when compared with total contact cast and TAL (38%) at 2 years follow-up (12). However, the intended goal was to reach 10° of dorsiflexion at the time of the intervention. Although TAL may be an effective way to assist healing and prevent recurrence of ulceration, a substantial ankle weakness, and reductions in plantar flexor torque has persisted beyond 8 months after surgery (13). In the same study, forefoot plantar pressure returned to high levels at 8 months as well. VOLUME 47, NUMBER 3, MAY/JUNE 2008
225
TAL can be performed, but not without complications (11). Heel ulcers are associated with ankle dorsiflexion of ⬎15° post-operative indicating a calcaneus gait (11). Other complications were also observed such as tendon rupture (10%), recurrence with ankle dorsiflexion ⬍10°, and Charcot arthropathy (4%). There is only one study addressing TAL in transmetatarsal amputations (TMA). In 1993, Barry et al. performed 33 TAL for the treatment of chronic ulcerations after TMA (14). The procedure achieved 91% healing rate and failed to heal 6% of the ulcers. However, no assessment of recurrent ulcerations after the procedure was done. In 1949, McKittrick et al (15) proposed the procedure as foot salvage for diabetic patients with infection or gangrene. However, the benefit of performing a partial foot amputation is well established in the medical literature. The more proximal the amputation, the greater the energy cost of ambulation and the lower the level of subsequent independent functioning (16). Inadequate blood flow, smoking history, and end-stage renal disease are risk factors for poor outcome following a TMA (17-19). Prompt healing of TMA is associated with good ambulatory capacity (19). In a retrospective study by Blume et al., initial healing of TMA (62/91) correlated significantly with the ability to ambulate and overall limb salvage. Also, tendon balancing procedures have been suggested to reestablish a plantigrade stump (20). Recurrent ulcerations have been well documented following partial foot amputations and transmetatarsal amputations (14, 21, 22). Kelly et al., demonstrated the peak plantar pressures of the transmetatarsal amputation side were 16% higher than those of the contralateral side but the difference was not statistically significant. In addition, there was no significant difference in peak plantar pressures in subjects with diabetes mellitus and transmetatarsal amputation compared with control subjects. We feel that the outcomes of this procedure are related to variation in the evaluation of equinus, the subjectivity in determining intraoperative amount of dorsiflexion necessary, and pedal deformities associated to the ulcers. The aim of the study was to investigate the incidence rate of new and recurrent ulcerations after percutaneous Achiilles’ tendon lengthening as an isolated procedure once the target ulcers healed.
Research Design and Methods We reviewed medical records from a period of January1995 to March 2007 at the University of Texas Health Science Center at San Antonio who underwent TAL for plantar ulcerations. Thirty-five medical records were reviewed from subjects who had undergone TAL for neuropathic ulcers after transmetatarsal amputation (TMA). 226
THE JOURNAL OF FOOT & ANKLE SURGERY
Twenty-eight charts were included for the final review and data collected in 28 lower extremities. Seven charts were excluded because of deep infected ulcers, previous TAL, TAL performed for other purpose other than plantar neuropathic ulcers, TAL performed concomitantly with other procedures, inability for subjects to return to prescribed shoewear, and osseous equinus abnormal metatarsal parabola, and overgrowth of bone leading to ulceration. Radiographs were reviewed to assess structural deformities. Subjects included in this review had plantar ulcers in TMA, gastroc-soleus equinus, peripheral neuropathy, and no vascular disease to contraindicate the procedure. Gastro-soleus equinus was assessed clinically by fully extending the knee, maximally dorsiflexing the ankle, and flexing the knee. Gastroc-soleus equinus was diagnosed when the ankle did not dorsiflex beyond perpendicular in relation to the fibula when the knee was flexed, and the foot in neutral position (23). Evaluation of equinus was performed by the surgeon during the preoperative visit. Procedures were performed by multiple surgeons. Peripheral neuropathy was confirmed using a biothesiometer, 5.07g monofilament following the criteria suggested by Birke and Sims, 1986 (24). In those patients who had an absent pulse, non-invasive vascular assessment was performed prior to the procedure. All those with an ankle-brachial index of ⬎0.80 were considered candidate for the procedure, and non-healing ulcers with equinus. Twenty-one ulcers were located in the distal transmetatarsal stump, and 7 in the plantarlateral midfoot (not related to Charcot deformity). The procedure was performed with aseptic techniques, under general or local anesthesia. The Achilles’ tendon was surgically lengthened by different surgeons as described by Hoke (25). Three percutaneous incisions were performed approximately 3 cm apart from each one, and careful continuous dorsiflexion of the foot was applied until it passed perpendicular in relation to the fibula. No adjunct procedures were performed. Incisions were approximated with sutures or steri-strips. All subjects were allowed to partially bear weight after surgery with removable cast boot or total contact cast until ulcer healed. All patients were prescribed and returned to extra-depth shoes with prescribed insoles. For statistical analysis, we used binomial distribution for dichotomous variables because the data was collected based on the possibility of whether a new or recurrent ulceration occurred. Based on previous data from Holstein’s and Lin’s study (6, 11), we expected that 20% of subjects will develop a new and recurrent ulcer. For the analysis, a new ulcer was defined as an ulcer that appeared in another location once the target ulcer healed. A recurrent ulcer was defined as an ulcer that appeared once the target ulcer healed. A posteriori power analysis indicated that with a fixed number of 28 subjects, and an expected proportion of .20 (that is, 20% of subjects will develop a new ulcer) at a 90%
Table 1
Mann-Whitney test
Age by Recurrence
no yes Median difference 95.1% CI Mann-Whitney’s statistic Z statistic 2-tailed p
Table 2 n
Rank sum
Mean rank
U
18 262.5 14.58 88.5 10 143.5 14.35 91.5 0.5 -12.0 to 11.0 (normal approximation) 88.5 0.07 0.9426 (normal approximation, corrected for ties)
Fisher exact test
Gender
Female Male Total Difference of proportions 95% CI 2-tailed p
Recurrence
Total
no
yes
4 14 18 -0.200
4 6 10
8 20 28
-0.600 to 0.200 (normal approximation) 0.5679 (exact, double 1-tailed p)
Table 3
confidence interval, statistical significance can be detected. For the analysis, we used an alpha level of 0.05. Statistical analysis was performed by one of the co-investigators (MA), using Analyse-it® for Microsoft Excel (version 2.03; Microsoft Corporation, Redmond, WA).
Test Title Null Hypothesis n
Recurrence
Results The outcome of the study was to investigate the incidence rate of new and recurrent ulcerations in TMA after the original ulcers healed with percutaneous Achilles’ tendon lengthening as an isolated procedure. A target ulcer is the ulcer which the intervention was performed in order to heal. A new ulcer was defined as an ulcer that appeared in another location once the target ulcer healed. A recurrent ulcer was defined as an ulcer that appeared once the target ulcer healed. Median age of subjects was 51 years (range 24-72 years). All subjects were type 2 diabetic patients. There were 20 males and 8 females. All procedures were unilateral. Twenty-four ulcers were grade 1A, 2 were 0A, 1B and 1 was 1C using the UT wound classification system (26). The one ulcer that was considered 1B (infected) was prescribed oral antibiotics prior to the procedure. The two ulcers that were classified as 0A were included in the study because at the time of the procedure they were 0A, however, the ulcer continue to recur once the subjects returned to prescription shoes. Twenty-four ulcers healed, and four patients did not heal the ulcers. The 2 ulcers classified as 0A, were considered healed since they were no longer areas of impending cutaneous compromise. The 4 ulcers which did not heal were included in the study since the final outcomes were to assess new and recurrent ulcers after the intervention. Mean time to heal the ulcers after TAL was 9.4 weeks (range 3-72 weeks). To evaluate association between age and recurrence we used Mann Whitney test for parametric measurement. No statistical significance was found (Table 1). To evaluate association between gender and recurrence we used Fisher exact test. No statistical significance was
Binomial Test Recurrence after TAL Recurrence: no ⫽ 0.2 28
Total Hypothesized proportion Proportion 95% CI 2-tailed p
Total
no
yes
18 0.200
10
28
0.643 0.441 to 0.814 (exact) ⬍0.0001 (exact, double 1-tailed p)
Table 4 Test Title Null Hypothesis n
Binomial test New ulcers after TAL New Ulcer: no ⫽ 0.2 28 New Ulcer
Total Hypothesized proportion Proportion 95% CI 2-tailed p
Total
no
yes
12 0.200
16
28
0.429 0.245 to 0.628 (exact) 0.0099 (exact, double 1-tailed p)
found (Table 2). Ten limbs had an ulcer recurrence (p⬍0.0001) [Table 3], and 6 developed new ulcers in different foot location. Five new ulcers were located at the heel, and 1 sub-5th metatarsal stump. Therefore, of the 28 limbs in which TAL was performed, a total of 16 limbs developed new ulcers at the time of follow up, including all recurrent ulcers (p⬍0.0099) [Table 4]. Of the 16 new ulcers, 5 were heel ulcers (p⬍0.0003) [Table 5]. The incidence of recurrent ulcerations after initially healing following TAL VOLUME 47, NUMBER 3, MAY/JUNE 2008
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Table 5 Test Title Null Hypothesis n
Binomial test Heel ulcers after TAL Heel ulcer: no ⫽ 0.47 28 Heel ulcer
Total Hypothesized proportion Proportion 95% CI 2-tailed p
Total
no
yes
23 0.470
5
28
0.821 0.631 to 0.939 (exact) 0.0003 (exact, double 1-tailed p)
for the treatment of neuropathic foot ulceration was 35% (10/28). The incidence of new ulcerations after initially healing following TAL for the treatment of neuropathic foot ulceration was 21% (6/28). There were no complications such as tendon ruptures, infections, or amputations associated with the TAL. Discussion The role of gastroc-soleus equinus in the development of foot ulceration has been studied extensively. The Achilles tendon in diabetic patients has increased density of collagen fibrils, abnormal fibril morphology with disorganized collagenous fibers, and therefore, increased stiffness and plantar pressures (10). Several studies have demonstrated that percutaneous TAL has an effect in peak plantar pressure and ankle range of motion. Armstrong and colleagues showed in a retrospective study that peak plantar pressure decreases under the forefoot up to 8 weeks after TAL (7, 8). Maluf et al. (13) showed that a temporary reduction in peak forefoot pressure is noticed on those subjects that TAL is performed, but at 8 months, forefoot pressure and plantarflexory moment and power increased significantly. Their results suggest that TAL causes a temporary reduction in forefoot pressure primarily by reducing plantarflexory power during gait. The authors attributed the late increase in forefoot pressure to the plantarflexory muscles’ regaining strength after TAL. Although our study did not measure peak plantar pressures or muscle power, these observations may explain the high number of new ulcers in our study at an average of 2 years follow up. Recurrence of forefoot ulcerations after TAL ranges from 19% to 38% (6, 12). Mueller in 2003 demonstrated in a randomized clinical trial that TAL prevents recurrence of ulcers when compared to the group which did not undergo TAL. The study involved sixty-four subjects randomized 228
THE JOURNAL OF FOOT & ANKLE SURGERY
into two treatment groups, total contact cast group and total contact with TAL group (12). At the time of the two-year follow-up, twenty-one (81%) of the twenty-six patients in the total-contact cast group and ten (38%) of the twenty-six patients in the TAL group had ulcer recurrence. Holstein et al. (11) demonstrated in his study a high incidence of recurrence and heel ulcers. In his retrospective review, of 68 patients and 75 ulcers, they noticed healing of the ulcers was obtained in 68 of 75 feet (91%). At a median follow-up of 12 months, a healing rate of 60 of 75 ulcers was accomplished (80%). Acute transfer ulcers to the heel occurred in 47% of patients and they were associated with excessive dorsiflexion (⬎15°) in the neuropathic heels. The authors concluded that lengthening of the Achilles tendon is effective in healing plantar neuropathic ulceration, but the procedure should be performed only in a setting that can manage complication and new ulcers. Our study showed similar findings as Holstein and Mueller. Ten of the 28 patients (35%) treated with TAL developed recurrence by the time of follow up. Also, six ulcers occurred in a new area not related to the target ulcer (5 in the heel, and 1 in the forefoot). A total of sixteen new ulcers at a follow-up of 2.4 years occurred in our study which represents findings similar to previous studies. Many clinicians agree that equinus may play a limited role in ulcer development. Orendurff (27) studied the relationship of equinus in peak plantar pressure in 27 subjects. Simple linear regression showed that the relationship between equinus and peak forefoot pressure was significant (p ⬍ 0.0471), but that only a small portion of the variance was accounted for (R(2) ⫽ 0.149). They concluded that equinus has only a limited role in causing high forefoot pressure. We also agree with Orendurff that equinus has only a limited effect on forefoot pressure. Also, Holstein’s study had seven ulcers which did not heal (10%) to 6 of which he attributed digital deformities as the primary cause. Although we did not analyze other risk factors, we concur with Holstein’s study. In our study, four ulcers did not heal, and of the 5 heel ulcers, 2 occurred in the subjects with 0a ulcers as the target ulcer. Our study has its limitations. First, we did not measure preoperative and post-operative dorsiflexion, which is an important factor when investigating the association between dorsiflexion and the development of heel ulcers after the procedure. Secondly, a true correlation between risks factors that may lead to recurrent or new ulcer formation after TAL could not be determined. Although we feel that variables such as age, gender, duration of ulcer, control of diabetes, UT grade may play a role in healing the ulcer, the authors failed to analyze those variables. We feel, however, that these variables may not play a role in developing recurrence or new ulcer formation. Our study does confirm that in a clinical setting
where TAL is performed commonly as the treatment of ulcers, careful monitoring should continue. We are able to conclude that a high recurrence and new ulcer formation exist after TAL in a clinical setting, and other extrinsic and intrinsic factors may need to be addressed. TAL should be performed for treatment of neuropathic ulcerations as an adjunctive procedure to appropriate shoegear, deformity correction, and pedal education.
13.
14.
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