Functional Outcomes of Achilles Tendon Minimally Invasive Repair Using 4- and 6-Strand Nonabsorbable Suture: A Cohort Comparison Study

BACKGROUND The aim of management of Achilles tendon rupture is to reduce tendon lengthening and maximize function while reducing the rerupture rate and minimizing other complications. PURPOSE To determine changes in Achilles tendon resting angle (ATRA), heel-rise height, patient-reported outcomes, return to play, and occurrence of complications after minimally invasive repair of Achilles tendon ruptures using nonabsorbable sutures. STUDY DESIGN Cohort study; Level of evidence, 3. METHODS Between March 2013 and August 2015, a total of 70 patients (58 males, 12 females) with a mean age of 42 ± 8 years were included and evaluated at 6 weeks and 3, 6, 9, and 12 months after repair of an Achilles tendon rupture. Surgical repair was performed using either 4-strand or 6-strand nonabsorbable sutures. After surgery, patients were mobilized, fully weightbearing using a functional brace. Early active movement was permitted starting at 2 weeks. RESULTS There were no significant differences in the ATRA, Achilles Tendon Total Rupture Score (ATRS), and Heel-Rise Height Index (HRHI) between the 4- and 6-strand repairs. The mean (SD) relative ATRA was -13.1° (6.6°) (dorsiflexion) following injury; this was reduced to 7.6° (4.8°) (plantar flexion) directly after surgery. During initial rehabilitation at 6 weeks, the relative ATRA was 0.6° (7.4°) (neutral) and -7.0° (5.3°) (dorsiflexion) at 3 months, after which ATRA improved significantly with time to 12 months (P = .005). At 12 months, the median ATRS was 93 (range, 35-100), and the mean (SD) HRHI and Heel-Rise Repetition Index were 81% (0.22%) and 82.9% (0.17%), respectively. The relative ATRA at 3 and 12 months correlated with HRHI (r = 0.617, P < .001 and r = 0.535, P < .001, respectively). CONCLUSION Increasing the number of suture strands from 4 to 6 does not alter the ATRA or HRHI after minimally invasive Achilles tendon repair. The use of a nonabsorbable suture during minimally invasive repair when used together with accelerated rehabilitation did not prevent the development of an increased relative ATRA. The ATRA at 3 months after surgery correlated with heel-rise height at 12 months.