The incidence of acute Achilles tendon rupture has increased during the past decade, reflecting the greater prevalence of people who are involved in sports, with the highest incidence in men aged 30 to 50 years.2 The treatment choices for the acute injury include nonoperative open surgery,22,28 and percutaneous,1,9,13,18,21 or minimally invasive surgery.2,5,16 There is still controversy regarding the best treatment to recommend.17,23,25,35 Open operative treatment is associated with a lower risk of rerupture compared with nonoperative treatment35; however, open surgery shows a higher risk of complications, including infection and disturbed skin sensibility.7 Percutaneous repair is associated with a lower complication rate compared with open operative repair7,10,14,17,19,32 but with a higher risk of reruptures and elongations.7,17
In the literature, we could not find a study that compares the results of a percutaneous surgical technique with a minimally invasive one. In this study, we compared the results of a modified percutaneous Ma and Griffith21 Achilles tendon repair with a minimally invasive technique.2
The primary aim of this study was to investigate the rate of rerupture and development of complications, especially sensory disturbances and infections, between these two techniques of Achilles tendon repair. The secondary aims were to compare the time for return to work and to sports and the clinical and functional outcomes as judged by the American Orthopaedic Foot and Ankle Society (AOFAS) score, leg circumference, plantar flexion peak torque, and endurance.
MATERIALS AND METHODS
We assessed 24 consecutive patients surgically treated for unilateral acute Achilles tendon rupture. The first 12 patientsNumber 458 May 2007(Group A) were treated with the modified Ma and Griffith technique21 and the next 12 patients (Group B) had the minimally invasive technique using the Achillon® system (Newdeal, Lyon, France).2 We included patients with an acute rupture (within 7 days) occurring between 2 and 8 cm proximal to the calcaneus tuberosity without general and local predisposing factors, such as diabetes, rheumatoid arthritis, local and general use of corticosteroids, previous class quinolone antibiotics therapy, or tendinopathies. In 23 patients, ruptures occurred during athletic activities, whereas only one rupture occurred during a nonathletic activity. In all cases, the diagnosis was based mainly on history and clinical examination (function impairments, palpation of the gap, Thompson test) and confirmed by ultrasonographic examination. The two groups were not different in terms of demographic and clinical variables, such as age, height of the lesion from the calcaneus tuberosity, and length of followup (Table 1), and we provided a power analysis for each parameter (Table 1).
For the percutaneous suture, the patient was placed in a prone position under general, spinal or peripheral nerve block anesthesia with the knee flexed at 15°. Both feet were prepared in the surgical field to adapt the tension of the suture to the physiologic equinus of the uninjured side. A pneumatic tourniquet was optional. The tendon defect was identified on palpation and three pairs of 5-mm skin incisions were made medial and lateral to the tendon edge: one pair at the lesion site, one pair distally at the distal stump site, and one pair proximally at the proximal stump site, both in healthy tendinous tissue. To minimize the risk of trapping the sural nerve at the proximal stump, the two skin incisions were made closer together. With small forceps, the paratenon was opened at each incision level. The modification of the original Ma and Griffith21 technique consisted of two Number 2 Bunnell-type bioresorbable sutures, which were passed on each stump with a large needle beginning transversely from the proximal and distal couples of the incisions. Then the sutures were tightened and knotted up to the foot reaching the same equinus position of the uninjured foot. The skin incisions then were sutured with 3-0 resorbable sutures.
For the minimally invasive group, we used the technique reported by Assal et al.2 With the patient in the prone position and under tourniquet at the thigh level, we made a longitudinal medial paratendinous incision 2 to 3 cm in length at the lesion level. The paratenon was incised and the proximal stump was identified. Pulling the proximal tendon stump with forceps, the Achillon® device was introduced under the fascia with the stump that comes between the two internal branches. When the device was introduced, it was gradually widened to follow the progressive proximal enlargement of the tendon. Three Number 1 absorbable sutures then were passed through the Achillon® branches and the tendon with a straight needle. The device was then slowly withdrawn and progressively closed. In this way, the three sutures exit from the incision, trapping the proximal tendon stump inside the fascia.1 The same maneuvers were performed in the distal stump. The six sutures were knotted with the foot in the same equinus position of the uninjured side. Suturing of the paratenon and the skin was then performed using 3-0 resorbable sutures.
A walker boot at 25° to 30° plantar flexion was applied in both groups directly in the operating room (Fig 1). Soon after surgery, antithromboembolic therapy was initiated and continued until the ninth week. All sutures were removed 15 days after surgery.
In both groups, we instituted the same semifunctional rehabilitation program (Fig 1). The walker boot was maintained for 8 weeks. During the first 2 weeks, the patient was at rest without weightbearing. At the beginning of the third week, a partial load up to 15 kg was permitted and home cycling with splint was started. At the beginning of the fourth week, the boot was locked in a neutral ankle position and active motion without the boot was permitted from 0° to 30° plantar flexion. At the sixth week, partial load was permitted up to 25 kg and progressively up to full load, associated with active motion with 5° dorsiflexion. After 8 weeks, progressive full load was reached and the orthosis was abandoned. A more intensive program of ankle motion, stretching, isometric, and proprioceptive exercises was then progressively instituted.
Followup in both groups was based on the clinical AOFAS rating score, associated with other additional findings, such as neurologic deficit (sural nerve), measurement of calf, thigh, and ankle circumferences, and range of motion in comparison with the contralateral leg.
In addition, both groups were evaluated with isokinetic dynamometry (Cybex; Easytech, Florence, Italy) of both limbs, after correction for gravity. Concentric plantar flexion peak torque (in Newtons/meter) was registered with five successive cycles at an angular velocity of 60°/second. Endurance was defined as total work done (in Joules) during the test time and was measured with 30 cycles at 240°/second. The percent differences in peak torque and total work were calculated using the unaffected side as a reference.
All sections were viewed by two individuals (BL, GL) who were blinded to the results.
All continuous data were expressed in terms of mean and standard deviation (SD). The Mann-Whitney test evaluated by Monte Carlo methods for small samples was used to test the hypotheses regarding differences between the two surgical treatments. The Pearson regression analysis and correlation coefficient were performed to investigate relationships between isokinetic data and calf circumference. For all tests, p < 0.05 was considered significant. Statistical analysis was performed by means of SPSS Version 7.5 software (SPSS Inc, Chicago, IL). We conducted a power analysis post hoc; in the power analysis, we assumed a value for the reference difference (Δ) that was clinically significant for each variable.
There was no difference regarding the rate of rerupture of the tendon between the two surgical techniques: no reruptures of the tendon were reported in either group.
The two groups revealed no differences concerning disturbed sensibility: none of the patients had sensory disturbances of the ankle and foot, in particular in the sural nerve distribution.
No patient had a deep or superficial wound infection. In Group B, one patient had a deep venous thrombosis during the third week. He was treated with a pharmacologic protocol: low-molecular-weight heparin subcutaneous injection (nadroparin calcium, 0.1 mL/10 kg body weight) until resolution of the problem and recovery of regular ambulation.
No difference was detected between the two groups regarding the time to return to sports activity. Twenty-two patients returned to their same level of sports activity after 5 months and only two patients (one in Group A and one in Group B) decided not to resume sports activities for reasons unrelated to the injury.
There was no difference in mean AOFAS score between the two groups: 98.0 (SD, 5.7; range, 80-100) in Group A and 100 (SD, 0; range, 100-100) in Group B. Only one patient had 80/100 because of moderate pain at the site of the scar because of the presence of subcutaneous nodules.
The two groups of patients had similar durations of the time for absence from work: the patients in Group A returned to their previous work activity after an average of 12 weeks (SD, 1.7) and the patients in Group B after an average of 11 weeks (SD, 1.3). Active maximum plantar flexion and dorsiflexion at followup were equal to the contralateral leg in both groups.
Calf circumference was diminished in the injured leg as compared with the contralateral leg in all cases, but the degree of calf circumference reduction was less (p < 0.0005) in Group B as compared with Group A (Table 2). The mean circumference differences were comparable at the thigh and ankle levels in the two groups (Table 2).
In both groups, the percent differences in plantar flexion peak torque and endurance between the injured and contralateral leg were equivalent (Table 3).
In both groups, no correlation between the calf circumference and isokinetic peak torque and endurance was found in either the healthy or injured limbs. Force (Fig 2A) and resistance (Fig 2B) expressed at the level of the injured limb did not correlate with the calf circumference.
Subcutaneous ruptures of the Achilles tendon occur especially in active individuals who practice various levels of sports activities. The goal of treatment is to enable patients to return to the same activities before injury in as little time as possible. The numerous percutaneous or minimally invasive techniques used to repair the tendon presented in the literature are valid alternatives to open surgery, which reduce complications and disadvantages, as they are performed within 7 days for lesions from 2 to 8 cm from the tendon's heel insertion.2 The two techniques we compared represent the first and last generation in the treatment of this lesion.
We could not find a comparison of a percutaneous surgical technique with a minimally invasive one in the literature. The aim of this study was to compare the rates of rerupture and complications of the two techniques and to determine any differences between the techniques in terms of clinical and functional outcomes.
The main limitation of our study is the small sample size. However, the small sample of patients was attributable to the strict inclusion criteria we used to avoid confounding factors. Furthermore, the number of patients is similar to other comparative studies.3,12 The patients in our study did not all have the same gender, but this was to be expected in a consecutive series of patients. Gender does not seem to be a critical factor for outcomes, as we have seen in the literature.7 And, finally, it is incorrect to overstate the results from a retrospective comparative study, even if the results are statistically significant.
All patients had high AOFAS scores, except for one patient in Group A with a score of 80/100 because of the presence of nodules causing moderate pain. The mean AOFAS scores of the two groups were high and agreed with those in the literature.2,4
No patients in this study experienced reruptures. In two recent meta-analyses17,35 that included percutaneous repair, the reported incidence of rerupture was very low (3.6%35 and 2.1%17).
In our study, no skin retraction or sural nerve or flexor hallucis longus tendon entrapment occurred, which, together with nodules at the suture area, are reported as complications of percutaneous techniques, with an incidence from 8.6%35 to 15%.17 To minimize the risk of sural nerve entrapment using the percutaneous technique, it is advisable to perform the two proximal incisions closer together than the others. The sural nerve crosses the lateral edge of the tendon approximately 9.8 cm proximally from the calcaneal insertion of the tendon.33
The main technical difference between the two procedures is that in the percutaneous technique suturing also includes the superficial fascia, whereas using the Achillon® device suturing occurs in the same fascia that is not entrapped. From a surgical point of view, the two techniques are comparable in our experience, considering the learning curve, even if using the Achillon® device involves greater complexity.
Both groups resumed work activity in a brief time: 12 weeks on average in Group A and 11 weeks on average in Group B. In the literature, a shorter time to return to work (22 days) was reported,4 but this probably is correlated to the type of work, which generally is not specified. The time to return to work depends on the characteristics of the work activity, especially whether it is sedentary-type work. The return to previous sports activity was similar in both groups: 5 months on average in Groups A and B. This amount of time is in agreement with previous studies2,4 and is consistent with a safe approach. Two patients (one in Group A, one in Group B) did not resume sports activities for reasons unrelated to the lesion.
With regard to reductions in thigh and sural circumferences compared with the healthy side (considering normal differences), the results at the thigh level were similar in the two groups (−0.25 cm on average in both groups), whereas the results at the calf level were substantially different between the two groups. The average reduction in calf circumference was greater in Group A (−1.25 cm; SD, 0.45) than in Group B (−0.25 cm; SD, 0.40). Bradley and Tibone3 found an intermediate value for calf circumference decrease after percutaneous repair (−0.9 cm).
Isokinetic evaluation of the two groups did not show a difference between the healthy and treated side, as also reported.2,3,12,29 The poorest results occurred in patients 70 years of age treated with the percutaneous technique. No differences were noted between the two groups.
Isokinetic results of force and resistance were not correlated in either group to calf circumference; a lesser calf diameter does not necessarily indicate a reduction in force expressed by the muscle, as reported by Leppilahti et al.20
The literature of the past decade indicates better results can be achieved with early functional rehabilitation.4,27 Some authors have shown a better orientation of the collagen fibers during healing, with an increase in scar tissue resistance associated with reduced thickness of the tendon when alternating tensions are applied to the repaired tendon.11,24,26
In this study, the limited thickness of the repaired tendon resulted in a good cosmetic appearance in both groups. An increase in ankle circumference after surgery was similar in both groups (+0.5 cm; SD, 0.48) and was less than that after open-surgery techniques.8 The mechanical stress that the repaired tendon experiences, however, should not exceed suture hold, which is less in minimally invasive techniques than in open techniques. For this reason, a semifunctional rehabilitative protocol beginning after 2 weeks of rest is preferred. In fact, Pneumaticos et al26 observed, at 2 weeks after surgery, the defect between the two tendinous heads was primarily made of immature fibroblasts with a decrease in the inflammatory response.
Immobilization with the use of a walker during the first 3 weeks after surgery at 25° to 30° plantar flexion appeared sufficient without the need to also immobilize the knee. As reported by Sekiya et al,31 the position of the ankle at 30° neutralizes the mechanical effect of traction on the repaired tendon even if the knee is placed in extension.
The percutaneous modified Ma and Griffith technique and the minimally invasive technique using the Achillon® System resulted in a high percentage of satisfactory clinical and functional outcomes. We consider these two techniques comparable: the only difference was the reduction in calf muscle circumference, which was less in the group treated with the minimally invasive Achillon® System. Therefore, in both groups, the differences between the injured and uninjured legs did not lead to reductions in muscle strength and permitted the same return time to preoperative levels of activity.
We thank Antonio Sinopoli for invaluable editorial assistance and for preparation of the tables and figures.
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© 2007 Lippincott Williams & Wilkins, Inc.
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