Background: Open hamstring lengthening (oHSL) is commonly performed to decrease knee contracture and improve
gait and posture for children with spastic diplegia. Furthermore, percutaneous hamstring lengthening (pHSL) is also
gaining popularity as an alternative to the open approach. This study aimed to compare the results of pHSL versus
oHSL and to determine the efficacy and safety of the percutaneous approach.
Methods: This retrospective included 54 patients (108 knees) with spastic diplegia operated for flexed knee gait with
either open or percutaneous HSL. The mean age of the participants at the time of surgery was 10.3±1.7 years (age
range: 5-25 years) for the open and 8.5±1.5 years (age range: 7-23 years) for the percutaneous group. Overall, 29 and
25 children were subjected to oHSL and pHSL, respectively.
Results: The mean durations of follow-up were 19.1 months (range: 12-49 months) and 18.3 months (range: 14-
45 months) for oHSL and pHSL groups, respectively. In the open group, the mean of preoperative popliteal angle
decreased from 64.3±3.6 to 28.4±4.3 (P<0.001), and in the percutaneous group from 63.8±2.7 to 29.5±2.3 (P<0.001).
The obtained results revealed no significant differences between the two approaches leading to a similar improvement
among the investigated patients (P=0.83).
Although the Gross Motor Function Class Score improved significantly within each group (P<0.001); this improvement
was insignificant between the groups (P=0.88). The mean of hospital stay for the percutaneous group was 1.6 days
(range:1-3 days) compared to 3.6 days (range: 2-6 days) for the open group, which indicated a significant difference
(P=0.001). The mean values of total cost were $333 and $473 in the percutaneous group and open group (P=0.001),
respectively. There was no significant difference between the groups regarding the complication rate (P=0.85).
Conclusion: Percutaneous HSL is a safe, easy, rapid, and brief procedure that is as effective as the open technique for
children with spastic diplegia in a short period of time. However, it is essential to examine the effects of this approach
during longer follow-ups to generalize the findings of the current study.
Level of evidence: III