Distal hamstring elongation in the management of spastic cerebral palsy

Effectiveness of surgical and non-surgical management of crouch gait in cerebral palsy: A systematic review

BACKGROUND

Cerebral palsy (CP) is a prevalent group of neuromotor disorders caused by early injury to brain regions or pathways that control movement. Patients with CP exhibit a range of functional motor disabilities and pathologic gait patterns. Crouch gait, characterized by increased knee flexion throughout stance, is a common gait pattern in CP that increases energy costs of walking and contributes to ambulatory decline. Our aim was to perform the first systematic literature review on the effectiveness of interventions utilized to ameliorate crouch gait in CP.

METHODS

Comprehensive searches of five medical databases yielded 38 papers with 30 focused on orthopaedic management.

RESULTS

Evidence supports the use of initial hamstring lengthenings and rectus femoris transfers, where indicated, for improving objective gait measures with limited data on improving gait speed or gross motor function. In contrast, evidence argues against hamstring transfers and revision hamstring lengthening, with recent interest in more technically demanding corrective procedures. Only eight studies evaluated alternatives to surgery, specifically strength training, botulinum toxin or orthoses, with inconsistent and/or short-lived results.

CONCLUSIONS

Although crouch in CP is recognized clinically as a complex multi-joint, multi-planar gait disorder, this review largely failed to identify interventions beyond those which directly address sagittal plane knee motion, indicating a major knowledge gap. Quality of existing data was notably weak, with few studies properly controlled or adequately sized. Outcomes from specific procedures are confounded by multilevel surgeries. Successful longer term strategies to prevent worsening of crouch and subsequent functional decline are needed.

LEVEL OF EVIDENCE

Systematic review.

Development of knee function after hamstring lengthening as a part of multilevel surgery in children with spastic diplegia: a long-term outcome study

BACKGROUND

Hamstring lengthening commonly is performed for the treatment of flexed knee gait in patients with spastic diplegic cerebral palsy. Satisfactory short-term results after hamstring lengthening have been demonstrated in various studies. However, evidence for the effectiveness of hamstring lengthening to correct flexed knee gait is scant because of small and inhomogeneous case series, different surgical techniques, and short follow-up.

METHODS

The long-term results for thirty-nine patients with spastic diplegia and flexed knee gait who were managed with intramuscular hamstring lengthening as a part of multilevel surgery are presented. Standardized three-dimensional gait analyses and clinical examinations were performed for all patients preoperatively and at one, three, and six to twelve years postoperatively.

RESULTS

Significant improvements in kinematic parameters and the popliteal angle were noted at short-term follow-up (p < 0.01), supporting the results of previous studies. Long-term results showed significant deterioration of minimum knee flexion in stance and the popliteal angle (p < 0.01), whereas the improvements in the Gross Motor Function Classification System and Gillette Gait Index were maintained. This recurrence of flexed knee gait is partial and measurable. Increased pelvic tilt was found in 49% of the limbs postoperatively, which may represent one factor leading to recurrence of flexed knee gait. Genu recurvatum was seen in eighteen patients (twenty-seven limbs; 35%) one year postoperatively, especially in the patients with a jump knee gait pattern preoperatively. At long-term follow-up, genu recurvatum resolved in many limbs, but 12% of the limbs showed residual genu recurvatum, indicating that overcorrection represents a problem following hamstring lengthening.

CONCLUSIONS

The results of the present study are crucial for the prognosis of knee function after hamstring lengthening as a part of multilevel surgery. Recurrence and possible overcorrection should be considered in treatment planning.

Correction of severe crouch gait in patients with spastic diplegia with use of multilevel orthopaedic surgery

BACKGROUND

Severe crouch gait in patients with spastic diplegia causes excessive loading of the patellofemoral joint and may result in anterior knee pain, gait deterioration, and progressive loss of function. Multilevel orthopaedic surgery has been used to correct severe crouch gait, but no cohort studies or long-term results have been reported, to our knowledge.

METHODS

In order to be eligible for the present retrospective cohort study, a patient had to have a severe crouch gait, as defined by sagittal plane kinematic data, that had been treated with multilevel orthopaedic surgery as well as a complete clinical, radiographic, and instrumented gait analysis assessment. The surgical intervention consisted of lengthening of contracted muscle-tendon units and correction of osseous deformities, followed by the use of ground-reaction ankle-foot orthoses until stable biomechanical realignment of the lower limbs during gait was achieved. Outcome at one and five years after surgery was determined with use of selected sagittal plane kinematic and kinetic parameters and valid and reliable scales of functional mobility. Knee pain was recorded with use of a Likert scale, and all patients had radiographic examination of the knees.

RESULTS

Ten subjects with severe crouch gait and a mean age of 12.0 years at the time of surgery were studied. After surgery, the patients walked in a more extended posture, with increased extension at the hip and knee and reduced dorsiflexion at the ankle. Pelvic tilt increased, and normalized walking speed was unaltered. Knee pain was diminished, and patellar fractures and avulsion injuries healed. Improvements in functional mobility were found, and, at the time of the five-year follow-up, fewer patients required the use of wheelchairs or crutches in the community than had been the case prior to intervention.

CONCLUSIONS

Multilevel orthopaedic surgery for older children and adolescents with severe crouch gait is effective for relieving stress on the knee extensor mechanism, reducing knee pain, and improving function and independence.

Distal hamstring lengthening in cerebral palsy: the influence of the proximal aponeurotic band of the semimembranosus

We undertook a prospective review of 24 children with spastic diplegia treated by distal hamstring fractional lengthening at the Sheffield Children's Hospital. In 14 children (24 limbs) the correction achieved (popliteal angle) was inadequate and in these patients in the operating room a further correction was attained by dividing a tight band palpated in the substance of the semimembranosus muscle. Under general anaesthetic (preoperatively) the popliteal angle (a degrees ) was measured using a goniometer, then again (b degrees ) following distal hamstring fractional lengthening and finally (c degrees ) after surgically dividing the tight band. The mean preoperative popliteal angle (a degrees ) in all 24 limbs was 65 degrees (52-90). Following the standard hamstring fractional lengthening it (b degrees ) measured 37 degrees (35-50) and after division of the tight band it (c degrees ) measured 15 degrees (10-20). The reduction in popliteal angle following release of the tight band (proximal aponeurosis) was statistically significant (P<0.05). We undertook a cadaveric examination of 22 lower limbs and confirmed in all the cases that this band was the proximal aponeurosis of the semimembranosus muscle. The proximal aponeurosis is a well defined band located at the anterior aspect of the semimembranosus muscle where it arises from the tendon of the proximal attachment. It is separate from the distal aponeurosis. Division of the proximal aponeurosis during fractional lengthening of the distal hamstring in patients with cerebral palsy results in a significant reduction in the flexion deformity.

Novel biomechanics demonstrate gait dysfunction due to hamstring tightness

BACKGROUND

Children with cerebral palsy and hamstring tightness often demonstrate limited terminal swing knee extension. The conventional clinical measure of popliteal angle describes static hamstring tightness, but is not consistent with dynamic limitation. We hypothesize hamstring tightness, determined via modification of the conventional popliteal angle measure, is directly related to decreased terminal swing knee extension in children with cerebral palsy and normal magnitude knee flexion moments.

METHODS

Six patients with cerebral palsy and six normal subjects were evaluated via physical examination and instrumented gait analysis. Physical examination included popliteal angle measures at first hamstring resistance to passive extension (R(1)), and end-range extension (R(2)) with the hip in varying degrees of flexion. Passive R(1) data were used to calculate regression equations to predict R(1) during gait, resulting in a novel measure of Available Knee Extension. Hamstring EMG was also compared.

FINDINGS

R(1) during physical examination was significantly correlated with Available Knee Extension at terminal swing (Pearson r = -0.7251, P < 0.0001). Patients walked with significantly decreased velocity (0.959 vs. 1.27 m/s, P = 0.0002) and decreased knee extension at terminal swing (25.6 vs. 2.05 degrees, P < 0.0001), in the presence of normal knee flexion moments (-0.289 vs. -0.306 Nm/kg, P = 0.5009), and significantly decreased power absorption (-0.821 vs. -1.43 W/kg, P < 0.0001). Eleven of 12 patient knees demonstrated negative Available Knee Extension at terminal swing, with markedly limited knee extension. Five of 12 normal knees demonstrated negative Available Knee Extension, but this was near full extension. Hamstring EMG onset times were not significantly different.

INTERPRETATION

We believe Available Knee Extension, defined on the basis of clinical measures of first resistance to hamstring stretch, provides a biomechanical link between physical examination findings and dynamic limitations in terminal swing knee extension.

Kinematic and kinetic evaluation of the ankle joint before and after tendo achilles lengthening in patients with spastic diplegia

Fourteen patients, at a mean age of 9.1 years (range 4.1-16.6 years), who had spastic diplegic cerebral palsy were evaluated before and after tendo Achilles lengthening (TAL). Follow-up (by gait analysis) after TAL ranged from 8 to 30 months. A Vicon motion analysis system with six CCD cameras and two AMTI force plates provided three-dimensional measurements of joint motion and moments. The TAL procedure resulted in normal passive dorsiflexion of the ankle joint with the knee at 0 degrees of extension and 90 degrees of flexion, reduced plantarflexion during swing phase, and reduced premature plantarflexor moment. However, 10 degrees greater than normal dorsiflexion of the ankle joint during mid-stance phase was indicative of a mild calcaneal gait pattern. The TAL procedure improved lower extremity function as documented by both kinematic and kinetic analysis in cerebral palsy.

Distal hamstring lengthening in ambulatory children with cerebral palsy: primary versus revision procedures

To document the benefits and limitations of distal hamstring lengthening (HL), 61 children (105 limbs) with cerebral palsy treated by distal HL with complete preoperative and postoperative evaluations were reviewed. There was significant improvement in popliteal angle, fixed knee flexion contracture, knee angle at foot contact (FC), and mid-stance knee extension after HL. On the other hand, the hip power generation peak decreased, and the anterior pelvic tilt increased. For the repeated HL (22 limbs), the fixed knee flexion contracture and knee flexion at FC improved. In a group of ten patients (17 limbs) with further postoperative follow up evaluations, the only significant clinical finding related to hamstring function between the first postoperative and the follow up evaluations with no intervening surgery was an increase in the popliteal angle of 20 degrees. Because the popliteal angle may increase over time after HL with no other directly related gait changes, the indications for repeated HL should include fixed knee flexion contracture and increased knee flexion at FC. The increase in the popliteal angle alone should not be considered an indication for repeated HL.

Forward leaning reaching task in sitting (FLRS): a new measure for clinical evaluation of hamstring length in children

BACKGROUND AND PURPOSE

In this study, the rotation of the pelvis was taken into account when assessing the length of hamstrings. A new measure for clinical evaluation was developed to establish reference values of hamstring length in children without movement disabilities for different age groups. Subjects (N = 60) were 3-, 6-, 10- and 14-year-old children (N = 15 for each age group). These values could be helpful in deciding treatment interventions in children with movement disabilities, for example cerebral palsy, when hamstring length is in question.

METHOD

The study was performed with subjects sitting and reaching for a touch control on a wall whilst voluntarily rotating the pelvis forwards. By use of digitized video frames, the spatial angles of the lumbar spine and pelvis, as well as the joint angles of hip and knee, were computed at the initial and end positions of a forward leaning reaching task in sitting (FLRS). The active forward leaning induced a forward rotation of the pelvis, causing stretch on the hamstring muscle with extended knee.

RESULTS

The results of spatial and joint angle measurements suggest that the difference of the hip joint angle between initial erect and final forward leaned sitting may be used as reference values for hamstring length. Reference values are based on the mean (+/- SE) of means (mean of 15 children, that is, group and individual means of ten trials).

CONCLUSIONS

The age group reference values obtained may indirectly give information as to whether the hamstring length of a child with cerebral palsy is within the normative value of age-related control subjects. The new test developed in this study provides a convenient means for measuring hamstring length and could enhance clinical evaluation.

Hamstrings and psoas lengths during normal and crouch gait: implications for muscle-tendon surgery

Crouch gait, one of the most common movement abnormalities among children with cerebral palsy, is characterized by persistent flexion of the knee during the stance phase. Short hamstrings are thought to be the cause of crouch gait; thus, crouch gait is often treated by surgical lengthening of the hamstrings. In this study, a graphics-based model of the lower extremity was used in conjunction with three-dimensional kinematic data obtained from gait analysis to estimate the lengths of the hamstrings and psoas muscles during normal and crouch gaits. Only three of 14 subjects with crouch gait (four of 20 limbs with knee flexion of 20 degrees or more throughout stance) had hamstrings that were shorter than normal by more than 1 SD during walking. Most (80%) of the subjects with crouch gait had hamstrings of normal length or longer, despite persistent knee flexion during stance. This occurred because the excessive knee flexion was typically accompanied by excessive hip flexion throughout the gait cycle. All of the subjects with crouch gait had a psoas that was shorter than normal by more than 1 SD during walking. These results emphasize the need to consider the geometry and kinematics of multiple joints before performing surgical procedures aimed at correcting crouch gait.