The increase in rate of ATR has been considered associated with the emphasis of physical activity during recreational sports in recent years. In line with numerous studies and meta-analyses6,14, our patients were male-predominant. Although the best strategy for managing ATR remains controversial as mentioned, literature suggests a tendency for surgical intervention, as operation is advocated for active patients especially athletes who seek early return to previous high functional status12,13,23. Current evidence suggests that open compared to percutaneous repair has higher rates of wound complications, mainly infections, and almost double costs11,15,22,23,24,30,31,32. Propelled by these partially unsatisfactory complications, percutaneous repair of ATR has gained favour. In addition, some authors described a possible higher re-rupture rates with percutaneous techniques, from an incidence of 2.1%15 to even 17%18, although other studies are ambiguous on this7,9,20,22,23. As in our study, no reruptures were noted after percutaneous repair.
Injuries of the sural nerve remain the most described complication in percutaneous approach19,23,25,33, having an incidence high up to 16.7%13. Since the first description of percutaneous technique by Ma and Griffith34 in 1977, many modifications have been proposed thereafter18,29,31,35,36,37,38,39 for better vision of pathology and to reduce possible complications. Some were focused to prevent sural nerve damage, for example exposing the nerve35, making posterior18 or paramedial incisions37, and placing the knots at the medial aspect of the Achilles tendon36. No current studies could guarantee complete prevention of sural nerve lesions under percutaneous method, except the method by Amlang et al.37 with the aid of Dresden instrument, resulting no signs of sural nerve injuries under such technique33,37. In accordance with most literature, we found 4 amongst 36 patients (11.1%) in our study experiencing sensory disturbances after surgery. Although there were authors believing the injury was not restricted to operative techniques7, we regard their conditions iatrogenic based on the location of discomforts and the denial of related complaints prior to surgical intervention. The anatomic variations and courses of the sural nerve are considerable40,41, we tried to minimize the damage by making the incisions small and longitudinal paralleling the nerve with careful undermining. We also kept the incisions as close to the lateral tendon edge as possible relying on the anatomical identification by Kammar et al.41, which gave us the mean distances between the sural nerve and the Achilles tendon in respective heights, as well as the findings that the distance could be lower in older patients and men tended to have the nerve more lateral to the Achilles tendon insertion. Nevertheless, we concluded certain difficulties to fully protect the sural nerve, due to unidentifiable variants and possible nerve displacement by local soft tissue swelling in Achilles tendinopathy and paratendinopathy. Yet, nerve injuries were mostly temporary and there was a good chance of spontaneous resolution of symptoms.
There is no general accepted evaluation score for ATR treatments. In our study, we used ankle-hindfoot AOFAS and VAS score as subjective evaluation. AOFAS score is one of the mostly used assessment tools in foot surgery42 and was also seen in various studies acting as an outcome measure of ATR percutaneous repair22,31,43,44,45. Some authors have established subgroups of scores to define ‘excellent’, ‘good’, ’fair’ and ‘poor’ outcomes46. For instance, scores between 90 and 100 points are indicative of an ‘excellent’ result. Therefore, we regarded most of our patients to have excellent results. We found our mean AOFAS score comparable to the referenced studies although their combined results marked a slightly higher average score at 95.5(44-100), in which we believed it was contributory mainly to a much longer follow-up time (average 28.78 months, range 12-82) at the time of assessment. We chose the follow-up point at 12 months postoperatively for the patients to complete the survey as previous studies have shown functional scores following ATR repair may plateau beyond 1-year time point43,47. Similarly, VAS score for pain was evaluated at 12 months postoperatively. Our result was less than satisfactory compared to previous studies44,45 which gave a mean VAS score of 0.6 at an average follow-up period of 31.2 months. The difference observed was partly on account of the deviation caused by the higher VAS scores given by patients suffering from complications. However by crosschecking with the AOFAS questionnaire, we found only the patient requiring neurolysis gave a 30-points in the ‘pain’ category, otherwise full 40-points were recorded in the same category from all the remaining 35 patients. Another cause for higher value might be associated with the observational phenomenon in our region that patients appear to give an at-least-one-point in VAS even in years after injuries, no matter on how the treatment or improvements have been.
Although the AOFAS scoring contains questions evaluated by physicians, we considered the survey to be mostly subjective. The follow-up of ATR also needs to be realized objectively. US was chosen over other diagnostic imaging studies in our study as it acted as a reproducible, non-invasive, and cost-effective tool. Möller grading system29 was used to quantify our US findings. In our study, US was performed on each patient at a minimum of 12-month outpatient follow-up. As patients were asked to visit on an ad hoc basis, the average follow-up time for the US scores to be recorded was 18.3(12-21) months. We regarded the results representative as the changes in US findings after 12 months post injury were reported insignificant29. The US features of the Achilles tendon in all our patients after one year post surgery agreed with the tendon appearances described29. Furthermore, the mean positive points of 1.8(1-3) from our results were superior than that given by Möller et al. (mean 4.3, range 2-8) 29, which can be attributed to the development of better surgical techniques and advancement of rehabilitation protocols over years. Patients after surgical repair specifically percutaneous repair in our current study did demonstrate a smaller positive findings, in other words better results. On the other hand, none of our patients was presented with US abnormalities48 and the healing processes of all the examined tendons were healthy.
The concept of rehabilitation for ATR has changed notably as early dynamic functional rehabilitation, when compared with traditional postoperative immobilization, led to more excellent rated subjective responses and no difference in rerupture rate49,50. Our promotion of immediate weight bearing after surgical repair was also well acknowledged43,51,52. Early active ankle mobilisation results in reduces range of motion loss, increases blood supply, and reduces the degree of muscle atrophy53, all our patients were able to attain swifter near-to-normal range of motion restoration. Time of returning to sports was also pleasing, a shorter period was observed comparing to the general treated population23.
There are several limitations in this series. First, this is a retrospective case series with the absence of control group and a relatively small sample size. We were unable to report direct comparisons of clinical outcomes and ultrasonic evaluation due to the restriction by patient choice for treatment. Second, the follow-up period was relatively short compared to other existing case series. Nevertheless, we have elaborated a more-than-12-month evaluation was adequate for patients to reach a clinical and functional plateau and for the treated tendon to be well-healed. Third, it remains unclear to what extent the rehabilitation program could possibly affect our measurement on clinical outcomes. Furthermore, the rehabilitation of each patient was unsupervised, which may lead to individual differences in functional performance. Notwithstanding the stated limitations, strength of this study is the combination of subjective and objective quantitative measurement, namely the validated AOFAS with VAS score and ultrasonic evaluation respectively, which is different from previous studies.