Where Are We Now?
The distal rectus femoris transfer to the hamstring muscle is designed to address stiff knee gait in an ambulatory child with cerebral palsy. Patients with cerebral palsy who have problems walking on uneven ground—often needing a brace, or ambulatory aids such as a walker or crutches—typically are classified as level II or III patients on the Gross Motor Function Classification System (GMFCS) mobility assessment. Children with a stiff knee gait often fall during the day, and are observed to have compensatory gait accommodations of external rotation, ipsilateral circumduction, contralateral vaulting, or a combination of all of these. Treatment options for this disorder, prior to the introduction of the transfer, include proximal or distal lengthening of the rectus femoris. Most suggest that there is little improvement in the stiff knee component of gait in patients who had undergone these surgeries. As more research is performed on the rectus transfer, it is becoming apparent that this approach is not the panacea thought to eliminate stiff knee gait in all patients. This could be ascribed to undiagnosed underlying dystonia, increased scarring after the transfer, or not performing the procedure correctly. There still are authors who suggest that quality treatment of the stiff knee gait can be accomplished by performing a proximal rectus femoris release. Végvári and colleagues addressed this controversy in the current study.
The authors compared two groups of patients who underwent single-event, multilevel surgery, including many who had rotational osteotomies of their femurs and/or tibiae. One group had a distal rectus femoris transfer; the other had a distal rectus femoris transfer and a proximal rectus femoris release. The proximal rectus release group also had increased anterior pelvic tilt, which was a confounding factor. The authors’ short- and long-term findings demonstrated that there was no measureable difference between the two groups; the addition of the proximal rectus femoris release had no additional effect at the knee or hip joint kinematics. The authors presented their technical outcomes using kinematics from three-dimensional gait analysis, but did not show any patient-centered outcomes, or the impact of the surgery on participation.
Where Do We Need to Go?
Although the authors performed a good case-control study, controversy will continue to surround this topic because of the small amount of patients in each group. When further subdivided by GMFCS level, the researchers had even fewer patients to compare. Each of the patients had additional procedures which were not equivalent in the comparison groups. This is the biggest challenge to any researcher studying children with cerebral palsy. The only common thread among the diverse group of diagnoses is brain injury or deformity. The manifestations of these diverse brain injuries are legion, and it is impossible to find a control or comparison groups to study individual therapies, such as a tendon lengthening or transfer.
How Do We Get There?
In order to overcome these shortcomings, it is imperative to perform population-based, multicenter studies with large numbers of patients (bilateral and unilateral) at the GMFCS and Functional Mobility Scale levels. These types of studies require radiographic and gait analysis, as well as patient-centered outcomes. Some may even suggest collecting images of the brain in all of the patients as there may be vastly different responses to treatment based on their etiology. Of course, these studies are expensive and complex procedures. Discovering whether a surgery or intervention is superior to another in the midst of all of the “noise” is difficult at best. It is a credit to the authors of this paper that they attempted to do the best that they could in a noisy world. I agree with the authors’ conclusion that proximal rectus femoris lengthening does not have an effect on stiff knee gait, but I suspect that those who perform this surgery may not be dissuaded from doing so based on this paper.
Footnotes
This CORR Insights®is a commentary on the article “Does Proximal Rectus Femoris Release Influence Kinematics In Patients With Cerebral Palsy and Stiff Knee Gait?” by Végvári and colleagues available at: DOI:10.1007/s11999-013-3086-4.
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All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.
The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR® or the Association of Bone and Joint Surgeons®.
This CORR Insights® comment refers to the article available at DOI: 10.1007/s11999-013-3086-4.