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Comparison of hamstring transfer with hamstring lengthening in ambulatory children with cerebral palsy: further
Camila De Mattos1, K Patrick Do, Rosemary Pierce
1Hospital Estadual da Criança, Rio de Janeiro, Brazil.
Insights
Hamstring lengthening alone or with transfer effectively reduces knee flexion in children with cerebral palsy (CP). While both methods improve hip extension, the transfer technique shows greater initial gains, though long-term recurrence rates are similar.
Area of Science:
- Orthopedics
- Pediatric Surgery
- Gait Analysis
Background:
- Hamstring overactivity in children with cerebral palsy (CP) can cause gait abnormalities like jump or crouch gait.
- Traditional hamstring lengthening (HSL) aims to decrease knee flexion but risks weakening hip extension and recurrence.
- A modified technique involves hamstring lengthening plus transfer (HST) to potentially mitigate these risks.
Purpose of the Study:
- To compare the long-term outcomes of HSL versus HST for treating flexed knee gait in ambulatory children with CP.
- To evaluate recurrence rates of knee flexion and preservation of hip extensor power.
- Hypothesis: HST will result in less recurrence and better hip extensor preservation.
Main Methods:
- Retrospective review of 50 children with CP undergoing hamstring surgery for flexed knee gait.
- Subjects divided into HSL (18) and HST (32) groups.
- Pre-operative, post-operative, and long-term gait studies were analyzed (mean follow-up: 4.4 years).
Main Results:
- Both HSL and HST improved knee extension in stance long-term; straight leg raise slightly worsened in both groups.
- The HST group showed significant improvement in peak hip extension power early post-op, which increased further long-term.
- The HSL group had an initial decrease in hip extension power, returning to pre-operative levels long-term. Two cases of knee recurvatum occurred in the HST group.
Conclusions:
- No significant long-term difference in recurrence rates between HSL and HST for flexed knee gait in CP.
- Both techniques effectively reduce stance phase knee flexion long-term.
- The HST group demonstrated superior improvement in hip extension power, potentially justifying the added surgical time.
Background:
Overactivity or contractures of the hamstring muscles in ambulatory children with cerebral palsy (CP) can lead to either a jump gait (knee flexion associated with ankle plantar flexion) or a crouch gait (knee flexion associated with ankle dorsiflexion). Hamstring lengthening is performed to decrease stance knee flexion. However, this procedure carries the potential risk of weakening hip extension power as well as recurrence over time; therefore, surgeons have adopted a modified procedure wherein the semitendinosus and gracilis are transferred above the knee joint, along with lengthening of the semimembranosus and biceps femoris.
Purpose:
The purpose of our study is to evaluate the differences between hamstring lengthening alone (HSL group) and hamstring lengthening plus transfer (HST group) in the treatment of flexed knee gait in ambulatory children with CP. We hypothesized that recurrence of increased knee flexion in the stance phase will be less in the HST group at long-term follow-up, and hip extensor power will be better preserved.
Methods:
Fifty children with CP who underwent hamstring surgery for flexed knee gait were retrospectively reviewed. All subjects underwent a pre-operative gait study, a follow-up post-operative gait study, and a long-term gait study. The subjects were divided into two groups; HSL group (18 subjects) or HST group (32 subjects). The mean age at surgery was 9.9 ± 3.3 years. The mean follow-up time was 4.4 ± 0.9 (2.7-6.3) years.
Results:
On physical examination, both groups showed improvement in straight leg raise, knee extension, popliteal angle, and maximum knee extension in stance at the first post-op study, and maintained this improvement at the long-term follow-up, with the exception of straight leg raise, which slightly worsened in both groups at the final follow-up. Both groups improved maximum knee extension in stance at the initial follow-up, and maintained this at the long-term follow-up. Only the HST group showed significant (p < 0.05) improvement in the peak hip extension power in stance at the first post-op study, and this increased further at the final follow-up. In the HSL group, there was an initial slight decrease in the hip extension power, which subsequently increased to pre-operative values at the long-term study. Only the HST group showed increase of the average anterior pelvic tilt at the long-term follow-up study, although this was small in magnitude. There were two subjects who developed knee recurvatum at the post-op study, and both were in the HST group.
Conclusions:
There is no clear benefit in regards to recurrence when comparing HST to HSL in the long term. In both HSL and HST, there was reduction of stance phase knee flexion in the long term, with no clear advantage in either group. Longer follow-up is needed for additional recurrence information. There was greater improvement of hip extension power in the HST group, which may justify the additional operative time of the transfer.
Significance:
This study helps pediatric orthopedic surgeons choose between two different techniques to treat flexed knee gait in patients with CP by showing the long-term outcome of both procedures.
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