Twenty-seven studies (n=1,612) were included in the review. Of these, two were cohort studies with historical controls (n=165), 20 were before-and-after case series (n=783), two were anecdotal case series (n=642), one was a descriptive case series (n=19), one was a descriptive case report (n=2), and one was a case report (n=1).
All the studies were deemed to be weak regarding the level of evidence (level III or below).
Hip subluxation.
Five studies reported the number of hips subluxated or dislocated at final follow-up, of which two reported an improvement, one a deterioration and one no change with hip adductor release. The fifth study reported an adverse effect of adductor release on the contralateral hip.
Eight studies reported the uniformity of effect of adductor surgery on the number of hips subluxated or dislocated at final follow-up. Across the eight studies, there was an overall improvement in 32% of hips, worsening in 10% and no change in 58%.
Across five studies, 22% of hips required further surgery due to failure of the initial operation. Three of four studies reported an overall improvement in the centre edge angle following adductor surgery, with a total of 50% showing improvement, 25% deterioration and 25% no change across the four studies.
Range of motion.
An improvement was reported in hip abduction (6 studies), a decrease in hip flexion contractures (2 studies), an improvement in popliteal angle (1 study), and no change in hip extension (1 study), or hip internal rotation or hip external rotation (1 study) post-surgery.
Pelvic obliquity and scoliosis.
Scoliosis worsened in children with spastic quadriplegia with adductor surgery (1 study), pelvic symmetry improved (1 study), and pelvic obliquity occurred in 50% of cases (1 study).
Pain.
Two studies investigated hip pain. One reported that pain was just as likely post-surgery as in untreated controls; the other provided anecdotal evidence of a reduction in pain after soft tissue adductor releases compared with historical controls.
Functional limitation and activity.
Four studies investigated the effect of surgery on sitting stability and ability to transfer. One reported an improvement in standing in 50% of children, sitting in 36%, and walking in 23%. Another reported an improvement in sitting balance in 37% of children and standing balance in 56%. Two further studies provided anecdotal evidence of an improvement in sitting ability in a small number of children.
Societal limitation and context factors.
One study reported an improved ability to use nappies in 44% of children, and no change in 28%, with the outcome not being applicable to the remaining 28% of children studied.
Subgroups.
Three studies reported that younger children (under 3 or 4 years of age) had a better outcome, whereas eight studies did not report a difference in relation to age at surgery. Two studies reported children with spastic diplegia had better outcomes than children with quadriplegia, whereas one study reported no difference between ambulatory and non-ambulatory children. Six studies reported that low migration percentages were associated with better post-operative outcomes.