Hamstring Length Research Articles

Percutaneous Versus Open Hamstring Lengthening in Spastic Diplegic Cerebral Palsy.

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. 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. 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). 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.

ACUTE EFFECTS OF NEURAL GLIDING ON ATHLETIC PERFORMANCE

Neural mobilization has been used to treat individuals with musculoskeletal and neuromuscular pathologies, but research on neural mobilization in sports rehabilitation is scarce. Furthermore, there have been no studies investigating the effects of neural gliding on sport performance. The purpose of this study was to examine the differences between the acute effects of sciatic nerve gliding and lower extremity dynamic stretching exercises on hamstring flexibility and athletic performance. A cross-sectional, quasi-experimental design with block assignment was used. Twenty-seven (16 males, 11 females, age: 23.6 ± 2.65, height (m): 1.74 ± 0.12, weight (kg): 73.73 ± 16.09) healthy college students volunteered for the study. The neural gliding group had 14 subjects and the dynamic stretching group had 13 subjects. Participants performed a jogging or walking up stairs warm up at a self-selected pace prior to testing. Baseline data was obtained for each of the following measurements: bilateral hamstring flexibility using the active straight leg raise test measured by a digital inclinometer, vertical jump height, 20-yard shuttle run and 10 and 20-yard dash sprint. The participants then performed one of the assigned five-minute stretching protocol, bilateral sciatic neural gliding or dynamic stretching of the lower extremities, followed by the post-test data collection of the same measures. There were no significant group by time interaction for any of the six measurements (2 x 2 repeated measures ANOVA). However, significant time differences, pre-test vs post-test for all participants as one group, for right hamstring length (p = .001), left hamstring length (p = .002) and vertical jump (p = .028) were observed. Post hoc paired t-tests found a significant increase between the pre and post-tests in right hamstring flexibility, (p = .011) in the dynamic stretching group and left hamstring flexibility of participants in the neural gliding condition, (p = .004). When analyzing the groups individually, pre-test vs post-test, a significant difference in vertical jump was not observed in either group. Similar improvement in hamstring flexibility with both dynamic stretching and neural gliding exercises without a negative effect on three sports performance tests was demonstrated. Therefore, athletic performance will not be negatively affected by a pre-participation warm-up which includes neural gliding, but more research is needed. Level 3.

Pelvic Tilt Changes After Hamstring Lengthening in Children With Cerebral Palsy.

Flexion deformity of the knee is a common presentation in children with cerebral palsy with hamstring surgery as an option for addressing this. However, concerns with regard to increased pelvic tilt have been raised. The purpose of this study was to compare preoperative and postoperative pelvic tilt after isolated hamstring lengthening versus combined hamstring lengthening and the influence of Gross Motor Function Classification System (GMFCS) levels on pelvic tilt. This retrospective study included 46 ambulatory children with cerebral palsy who had had open medial hamstring lengthening (mean age at surgery, 11 y 11 mo; SD, 2 y 11 mo; GMFCS I, 16; GMFCS II 20; GMFCS III 10). Twelve children underwent isolated surgery and 34 children underwent combined surgery. The isolated hamstring procedures could be combined with foot and/or ankle-level surgery, as only the hamstring procedure would affect the pelvic tilt. Combined surgery was defined as hamstring lengthening with other procedures performed at the knee or more proximally. The preoperative and postoperative 3-dimensional gait analysis data were evaluated in this study. Both the isolated and combined hamstring lengthening groups showed no significant change in pelvic tilt ([INCREMENT]1.28, P=0.203; [INCREMENT]1.47, P=0.113, respectively). A significant change in pelvic tilt was seen in children functioning at GMFCS III ([INCREMENT]4.66, P=0.009) but not GMFCS I and II ([INCREMENT]0.37, P=0.718; [INCREMENT]0.48, P=0.697). Significant postoperative decreases in the knee flexion angle at initial contact were seen for both isolated ([INCREMENT]5.72, P=0.010) and combined hamstring lengthening ([INCREMENT]10.95, P<0.001). Hamstring lengthening, for the majority of patients, did not lead to a clinically significant change in mean pelvic tilt and improved knee flexion angle at initial contact. Children who functioned at GMFCS level III had an increase in anterior pelvic tilt and caution should be exercised in this group. Level IV evidence-case series.

Benefits of a musculoskeletal modelling decision making procedure on hamstring lengthening outcomes: a retrospective study

Benefits of a musculoskeletal modelling decision making procedure on hamstring lengthening outcomes: a retrospective study

Correlation Between SLR and Active Knee Extension Tests in LBP Patients with Tightened Hamstring

Background: The length of the hamstring muscle is measured indirectly. This evaluation can be done by doing the passive straight leg raising (SLR) test or performing an active knee extension (AKE) test. It is important to know how much these two tests are correlated to each other. If they are highly correlated, a high SLR degree may conclude a high amount of AKE. Objectives: The aim of this study was to determine the correlation between these two tests among patients with LBP having tightness in their hamstring muscle. Methods: The sample size was calculated to be 50 patients. Participants with chronic low back pain (LBP) and short hamstring were selected. The hamstring muscles length of the participants were assessed using two clinical tests, 1- AKE test, and 2- SLR test. Results: The mean ± SD of the hamstring length of the patients using the SLR method was 72.52 ± 10.32 degrees. Also, the mean ± SD of hamstring muscle length was 157.28 ± 7.70 degrees using the AKE test. There was a positive and significant correlation between Hamstring length score using SLR and Hamstring length in patients with AKE test (P < 0.05, r = 0.30). Conclusions: The results of this study showed that there is a correlation between the results of two types of testing hamstring muscle length including SRL and AKE tests among patients with LBP having tightness in their hamstring muscle.

Distal Femoral Extension Osteotomy with 90° Pediatric Condylar Locking Compression Plate and Patellar Tendon Advancement for the Correction of Crouch Gait in Cerebral Palsy.

Background:Various treatment modalities are available for the correction of crouch gait, ranging from hamstring lengthening to a combination of soft-tissue and bony procedures. We report the results of distal femoral extension osteotomy (DFEO) fixed with 90° pediatric condylar locking compression plate (LCP) and patellar tendon advancement (PTA) for crouch gait in children with cerebral palsy.Materials and Methods:A total of 26 patients (52 knees) with a mean age of 14.36 years (range 11.6–20 years) who presented with crouch gait were treated with DFEO and PTA. Patients were analyzed prospectively using clinical (knee flexion deformity, knee range of motion, extensor lag), functional (modified Ashworth, Tardieu scores, muscle strength, gross motor functional classification system [GMFCS], functional mobility scale [FMS], gross motor functional measure [GMFM]) and radiological (Koshino Index) outcome measures and followed up at a mean of 22 months (range 12–53 months).Results:There was an improvement in all outcome measures postoperatively, with improved function and independence. The mean knee flexion deformity improved significantly from 20.7° ± 6.59 to 0.67° ± 2.62, mean muscle strength of quadriceps improved from 3.01 ± 0.5 to 3.5 ± 0.54 and mean extensor lag improved from 20° ± 7.14 to 4.13° ± 4.16. The mean Koshino Index improved from 1.4 ± 0.16 to 1.0 ± 0.08. The mean GMFM-D improved from 15.58 ± 6.2 to 26.31 ± 5.8 and mean FMS for 5 m improved from 2.9 ± 1.09 to 3.6 ± 0.84, indicating significant improvement in household ambulation. There were four complications; transient peroneal nerve palsy in 3 patients, which recovered completely and 1 superficial wound dehiscence. There was no loss of fixation, tendon pull-out or deep infection.Conclusion:The combined procedure of DFEO and PTA can correct knee flexion deformity, restore knee extensor strength, and improve function in patients with crouch gait. The pediatric condylar LCP provides stable fixation to allow early mobilization and faster rehabilitation.

Clinical Comparison of Percutaneous and Open Hamstring Lengthening in Children with Spastic Cerebral Palsy

Clinical Comparison of Percutaneous and Open Hamstring Lengthening in Children with Spastic Cerebral Palsy

Clinical and gait analysis of isolated soft tissue release surgery in crouch gait patients

Aim: The aim of this study was to evaluate whether isolated soft tissue release operation provides clinical and kinematic improvement in crouch gait, which is one of the major walking problems in cerebral palsy (CP) patients.Material Methods: This retrospective study included 32 limbs of 16 patients aged between 4 and 12 years with crouch gait walking pattern due to cerebral palsy between January 2004 and December 2013. All patients underwent multilevel isolated soft tissue release surgery. The preoperative and postoperative GMFSC level, clinical findings and gait analysis data of the patients were recorded. Pre-operative and post-operative data, which are obtained at post-op 6th month clinical examination and gait analysis, was compared.Results: A total of 114 lower extremity soft tissue segments (mean 7.1 segments) were operated. The most common surgery was medial hamstring lengthening (22). GMFCS score was 2.38±0.5 before operation, 1.69±0.4 at postoperative controls,and popliteal angle decreased from 65.2±11.9 to 60.15 (p 0.05) . There was no significant difference in the range of motion and joint forces of the hips, knees and ankle joints. According to the kinematic data, the minimum hip flexion (15.22±16.45 vs 7.33±14.34 p0.05), initial contact knee flexion (33.25±14.26 vs 24.46±8.84 p0.05) and maximum knee flexion in the swing phase (49.5±12 vs 43±11 p0.05) were declined and midstance foot ankle dorsiflexion (-3.02±1 vs. 3.75±7 p0.05) was increased. When the temporospatial data were compared, it was observed that cadence (104.71±38.5 vs 89.59±35.31 p 0.05), double support time (161.3±90.2 vs 150.09±81.91 p 0.05) decreased after surgery. While decrease in cadence was statistically significant, there was no significant difference between the double support time periods. However, step length (mm) (655.14±247.7 vs 767.5±307 p 0.05) and step width (mm)(144.41±50.61 147.94±87.8 p> 0.05) increased in postoperative evaluation.Conclusions: Single-session isolated soft tissue release surgeries have borth positive effect on clinical and functional outcomes in selected CP patients with crouch gait walking disorder. Priority should be to correct bone deformities in patients with bone deformity.Keywords: Multilevel isolated soft tissue surgery; crouch gate; cerebral palsy.

Pre-operative hamstring length and velocity do not explain the reduced effectiveness of repeat hamstring lengthening in children with cerebral palsy and crouch gait

BackgroundHamstring lengthening surgery (HSL) is often performed to correct crouch gait in patients with cerebral palsy (CP). However, crouch can recur over time, and repeat HSL may be ineffective. One possible reason is that the hamstrings in repeat HSL patients are neither short nor lengthening slowly and would therefore not benefit from HSL. Research questionThis study aimed to determine whether the hamstrings are short and/or slow preoperatively only in patients with primary, and not repeat, HSL. MethodsWe compared pre- and postoperative dynamic semimembranosus muscle-tendon lengths for children with CP who had primary (N = 15) or repeat (N = 8) HSL to a group of control participants (N = 10). Outcome measures were compared between visits (pre- vs. postoperative) and groups (control, primary HSL, repeat HSL) using mixed model analysis. ResultsPreoperatively, hamstrings were shorter and slower than normal on average in both HSL groups (p < 0.001); all but 3 limbs (primary 26/28, repeat 13/14) had hamstrings that were shorter and/or slower than controls by more than two standard deviations. Postoperative improvements were observed in the primary HSL group for popliteal angle, initial contact knee flexion, minimum stance knee flexion, and dynamic hamstring length (p ≤ 0.001). The repeat HSL group improved only in dynamic hamstring length (p = 0.004) and worsened in passive knee extension (p = 0.01) and minimum hip flexion in stance (p = 0.04). Hamstrings in both surgical groups on average remained shorter and slower than controls postoperatively (p ≤ 0.001). SignificanceThe fact that repeat HSL is less effective in improving knee motion is not due to a lack of short or slow hamstrings preoperatively. However, in recurrent crouch, short or slow hamstrings do not usually indicate hamstring dysfunction, and correction of other deformities such as rotational malalignment, fixed knee flexion contractures, patella alta, weak calf muscles, and/or loose heelcords should be considered rather than repeat HSL.

Long-term muscle changes after hamstring lengthening in children with bilateral cerebral palsy.

To evaluate short-term (1y postoperatively; E1) and long-term (at least 4y postoperatively; E2) changes in hamstring muscle-tendon length (MTL) and lengthening velocity after hamstring lengthening in children with bilateral cerebral palsy (CP). Three-dimensional gait analysis was performed in 19 children (16 males, 3 females; 36 limbs; mean age at surgery 9y [SD 3y]; range 6-10y) with flexed knee gait, preoperative ankle dorsiflexion lower than 20 degrees, and CP before bilateral hamstring lengthening (E0), at E1 and E2. Hamstring MTL (normalized by leg length) and velocity were assessed via OpenSim software. MTL increased from E0 to E1 (p=0.004) and decreased from E1 to E2 (p<0.020). Hamstring lengthening velocity did not change. In the subgroup with short, not slow hamstrings, the increase in MTL was maintained at E2. Hamstring lengthening is an efficient procedure to lengthen short and/or slow hamstrings short-term. The desired outcome with maintenance of the postoperative changes in hamstring MTL is only achieved for preoperatively short, not slow hamstrings. Surgical hamstring lengthening can be confirmed via musculoskeletal modelling in OpenSim software. Surgical hamstring lengthening in cerebral palsy does not change hamstring lengthening velocity. Short, not slow hamstrings present a long-lasting muscle-tendon length (MTL) increase after hamstring lengthening. Changes in MTL after hamstring lengthening cannot be maintained for slow hamstrings. MTL does not change after hamstring lengthening for neither short nor slow hamstrings.

Pre‐operative hamstring length and velocity do not explain the reduced effectiveness of repeat hamstring lengthening to correct crouch gait in children with cerebral palsy

Pre‐operative hamstring length and velocity do not explain the reduced effectiveness of repeat hamstring lengthening to correct crouch gait in children with cerebral palsy

P 026 – The effects of the in-toeing gait pattern on plantar pressure behavior and foot posture

Hamstring lengthening surgery (HSL) is often performed to correct crouch gait in patients with cerebral palsy (CP). However, crouch can recur over time, and repeat HSL may be ineffective. One possible reason is that the hamstrings in repeat HSL patients are neither short nor lengthening slowly and would therefore not benefit from HSL.This study aimed to determine whether the hamstrings are short and/or slow preoperatively only in patients with primary, and not repeat, HSL.We compared pre- and postoperative dynamic semimembranosus muscle-tendon lengths for children with CP who had primary (N = 15) or repeat (N = 8) HSL to a group of control participants (N = 10). Outcome measures were compared between visits (pre- vs. postoperative) and groups (control, primary HSL, repeat HSL) using mixed model analysis.Preoperatively, hamstrings were shorter and slower than normal on average in both HSL groups (p < 0.001); all but 3 limbs (primary 26/28, repeat 13/14) had hamstrings that were shorter and/or slower than controls by more than two standard deviations. Postoperative improvements were observed in the primary HSL group for popliteal angle, initial contact knee flexion, minimum stance knee flexion, and dynamic hamstring length (p ≤ 0.001). The repeat HSL group improved only in dynamic hamstring length (p = 0.004) and worsened in passive knee extension (p = 0.01) and minimum hip flexion in stance (p = 0.04). Hamstrings in both surgical groups on average remained shorter and slower than controls postoperatively (p ≤ 0.001).The fact that repeat HSL is less effective in improving knee motion is not due to a lack of short or slow hamstrings preoperatively. However, in recurrent crouch, short or slow hamstrings do not usually indicate hamstring dysfunction, and correction of other deformities such as rotational malalignment, fixed knee flexion contractures, patella alta, weak calf muscles, and/or loose heelcords should be considered rather than repeat HSL.

Dynamic spasticity determines hamstring length and knee flexion angle during gait in children with spastic cerebral palsy

BackgroundPrevious researchers reported that popliteal angle did not correlate well with knee angle during gait in individuals with spastic cerebral palsy (CP). Research questionTo determine if hamstring spasticity, as measured by Modified Tardieu Scale (MTS) at rest, is associated with knee flexion angle at initial contact and midstance during gait. MethodsThirty ambulatory children (mean age 8.7 ± 2.4 years) diagnosed with spastic CP participated. The hamstrings’ spasticity was assessed in the supine position with the MTS, measuring R1 (muscle reaction to passive fast stretch), R2 (passive range of motion), and R2-R1 (dynamic component of spasticity). We conducted 3-dimensional computerized gait analysis and calculated semimembranosus muscle-tendon length and lengthening velocity during gait using musculoskeletal modeling and inverse kinematic analysis by OpenSim. Pearson correlation coefficients were calculated to estimate the association of MTS with biomechanical parameters during gait. ResultsKnee flexion angle at initial contact and maximal knee extension angle during stance phase significantly positively correlated with both R1 and ㅣR2 - R1ㅣ of MTS, but not with R2 angle. The length of semimembranosus at initial contact, end of swing, and minimal length during stance phase were strongly negatively associated with R1, rather than R2 or ㅣR2 - R1ㅣ angles. SignificanceThe R1 angle of MTS (muscle reaction to passive fast stretch) is more relevant correlate of knee flexion angle during gait than the R2 (passive range of motion).

O 041 - Long-term outcome after hamstring lengthening in children with CP depends on preoperative hamstring length and velocity

Retrospective case series with comparative analysis.To analyze a consecutive cohort of very young patients operated for congenital scoliosis secondary to a single hemivertebra (HV) and compare thoracolumbar (TL) versus lumbosacral (LS) curve results.Despite the published successful results regarding early hemivertebra resection and short fusion for congenital hemivertebrae, literature lacks midterm results, especially in very young children.Patients under 5 years of age, operated by HV resection and transpedicular short fusion, with follow-up longer than 5 years, were included. Preoperative, postoperative (1-year), final radiographic parameters, and complications were recorded. Midterm results were analyzed and TL versus LS curves were compared.Twenty-three patients were included (14 TL and 9 LS HV). The mean age was 3.5 ± 1.7 years and the mean follow-up was 7.6 years (4.7–13.7). The mean preoperative Cobb angle (40.3° ± 6.7°), corrected 65% postoperatively and 50% at final follow-up. The compensatory cranial curve improved spontaneously from 25.3° ± 14.8° to 13.5° ± 12° and finally to 19.9° ± 10.7°. Preoperative coronal balance corrected postoperatively but worsened at the final follow-up. TL curves corrected more initially than LS curves (TL: −29°, 68%, vs. LS: −22°, 59%; p = .043); however, both groups lost correction at the final follow-up (TL: 4°, 56%, vs. LS: 7°, 39%; p = .186). The LS group had a larger preoperative compensatory curve, which corrected with surgery but lost more correction at the final follow-up (p = .046). Segmental kyphosis was especially corrected in the TL group (TL: −14° vs. LS: −2°, p = .018) and was maintained over time.Early hemivertebra resection and transpedicular short fusion allowed good coronal correction initially, which was difficult to maintain at midterm, especially at the LS junction. Sagittal plane correction was excellent in TL deformities and was maintained over time. Results were more challenging in the LS group compared with TL deformities. Guidance to avoid unwanted results is proposed.Level III.

Use of Hybrid Assistive Limb (HAL\xae) for a postoperative patient with cerebral palsy: a case report

BackgroundThe Hybrid Assistive Limb (HAL®) is an exoskeleton wearable robot suit that assists in voluntary control of knee and hip joint motion. There have been several studies on HAL intervention effects in stroke, spinal cord injury, and cerebral palsy. However, no study has investigated HAL intervention for patients with cerebral palsy after surgery.Case presentationWe report a case of using HAL in a postoperative patient with cerebral palsy. A 15-year-old boy was diagnosed with spastic diplegia cerebral palsy Gross Motor Function Classification System level IV, with knee flection contracture, equinus foot, and paralysis of the right upper extremity with adduction contracture. He underwent tendon lengthening of the bilateral hamstrings and Achilles tendons. Although the flexion contractures of the bilateral knees and equinus foot improved, muscle strength decreased after the soft tissue surgery. HAL intervention was performed twice during postoperative months 10 and 11. Walking speed, stride, and cadence were increased after HAL intervention. Post HAL intervention, extension angles of the knee in stance phase and hip in the pre-swing phase were improved. In the gait cycle, the proportion of terminal stance in the stance and swing phase was increased.ConclusionsHybrid Assistive Limb intervention for postoperative patients with cerebral palsy whose muscle strength decreases can enhance improvement in walking ability. Further studies are needed to examine the safety and potential application of HAL in this setting.

Influence of surgery involving tendons around the knee joint on ankle motion during gait in patients with cerebral palsy

BackgroundSimultaneous motion of the knee and ankle joints is required for many activities including gait. We aimed to evaluate the influence of surgery involving tendons around the knee on ankle motion during gait in the sagittal plane in cerebral palsy patients.MethodsWe included data from 55 limbs in 34 patients with spastic cerebral palsy. Patients were followed up after undergoing only distal hamstring lengthening with or without additional rectus femoris transfer. The patients’ mean age at the time of knee surgery was 11.2 ± 4.7 years, and the mean follow-up duration was 2.2 ± 1.5 years (range, 0.9–6.0 years). Pre- and postoperative kinematic variables that were extracted from three-dimensional gait analyses were then compared to assess changes in ankle motion after knee surgery. Outcome measures included ankle dorsiflexion at initial contact, peak ankle dorsiflexion during stance, peak ankle dorsiflexion during swing, and dynamic range of motion of the ankle. Various sagittal plane knee kinematics were also measured and used to predict ankle kinematics. A linear mixed model was constructed to estimate changes in ankle motion after adjusting for multiple factors.ResultsImprovement in total range of motion of the knee resulted in improved motion of the ankle joint. We estimated that after knee surgery, ankle dorsiflexion at initial contact, peak ankle dorsiflexion during stance, peak ankle dorsiflexion during swing, and dynamic range of motion of the ankle decreased, respectively, by 0.4° (p = 0.016), 0.6° (p < 0.001), 0.2° (p = 0.038), and 0.5° (p = 0.006) per degree increase in total range of motion of the knee after either knee surgery. Furthermore, dynamic range of motion of the ankle increased by 0.4° per degree increase in postoperative peak knee flexion during swing.ConclusionsImprovement in total knee range of motion was found to be correlated with improvement in ankle kinematics after surgery involving tendons around the knee. As motion of the knee and ankle joints is cross-linked, surgeons should be aware of potential changes in the ankle joint after knee surgery.

Mid-term development of hamstring tendon length and velocity after distal femoral extension osteotomy in children with bilateral cerebral palsy: a retrospective cohort study.

Flexed knee gait can be treated with distal femoral extension osteotomy (DFEO) and additional patellar tendon advancement (PTA) in children with cerebral palsy (CP). This study assesses changes in hamstring muscle tendon length (MTL) and velocity after DFEO (+PTA). Nineteen children (mean age 13y [standard deviation 3y] at surgery) with CP and flexed knee gait who were treated with DFEO (15 limbs) or DFEO+PTA (10 limbs) were retrospectively included in this study. Gait analyses were performed preoperatively (E0), 1 year postoperatively (E1), and for 10 limbs additionally 2 to 5 years postoperatively (E2). Hamstring MTL and velocities were assessed at all examination dates using OpenSim. Hamstring MTL and velocity did not change significantly over time. From E0 to E1, knee flexion in stance improved for both DFEO and DFEO+PTA (p<0.05), knee flexion in swing only improved after DFEO+PTA (p<0.05). The improved knee flexion in stance and swing was maintained at E2. DFEO led to a significant improvement in knee kinematics at E1 which was maintained at E2. DFEO seems to prevent recurrent hamstring tightness but does not lead to lengthened or fastened hamstrings. Distal femoral extension osteotomy (DFEO) does not change hamstring muscle tendon length. DFEO does not change hamstring lengthening velocity. DFEO leads to a significant improvement in knee kinematics. Changes in knee kinematics after DFEO can be maintained at mid-term. DFEO seems to prevent recurrent hamstring tightness.

Outcome of medial hamstring lengthening in children with spastic paresis: A biomechanical and morphological observational study.

To improve gait in children with spastic paresis due to cerebral palsy or hereditary spastic paresis, the semitendinosus muscle is frequently lengthened amongst other medial hamstring muscles by orthopaedic surgery. Side effects on gait due to weakening of the hamstring muscles and overcorrections have been reported. How these side effects relate to semitendinosus morphology is unknown. This study assessed the effects of bilateral medial hamstring lengthening as part of single-event multilevel surgery (SEMLS) on (1) knee joint mechanics (2) semitendinosus muscle morphology and (3) gait kinematics. All variables were assessed for the right side only. Six children with spastic paresis selected for surgery to counteract limited knee range of motion were measured before and about a year after surgery. After surgery, in most subjects popliteal angle decreased and knee moment-angle curves were shifted towards a more extended knee joint, semitendinosus muscle belly length was approximately 30% decreased, while at all assessed knee angles tendon length was increased by about 80%. In the majority of children muscle volume of the semitendinosus muscle decreased substantially suggesting a reduction of physiological cross-sectional area. Gait kinematics showed more knee extension during stance (mean change ± standard deviation: 34±13°), but also increased pelvic anterior tilt (mean change ± standard deviation: 23±5°). In most subjects, surgical lengthening of semitendinosus tendon contributed to more extended knee joint angle during static measurements as well as during gait, whereas extensibility of semitendinosus muscle belly was decreased. Post-surgical treatment to maintain muscle belly length and physiological cross-sectional area may improve treatment outcome of medial hamstring lengthening.

The Effects of Cupping on Hamstring Flexibility in College Soccer Players.

Context: College soccer players suffer from hamstring injuries due to inflexibility and repetitive motions involving intense hamstring lengthening and contraction during sport. Although it is a popular intervention for muscular injury, there exists limited evidence of the effects of therapeutic cupping on hamstring flexibility. Objective: To determine the effect of cupping therapy on hamstring flexibility in college soccer players. Design: Cohort design. Setting: Athletic training clinic. Patients: A total of 25, asymptomatic, National Collegiate Athletic Association Division III soccer players (10 males and 15 females; age = 19.4 [1.30]y, height = 175.1 [8.2]cm, and mass = 69.5 [6.6]kg). Intervention(s): A 7-minute therapeutic cupping treatment was delivered to the treatment group. Four 2-in cups were fixed atop trigger point locations within the hamstring muscle bellies of participants' dominant legs. Control group participants received no intervention between pretest and posttest measurements. Main Outcome Measures: Pretest and posttest measurements of hamstring flexibility, using a passive straight leg raise, were performed on both groups. Passive straight leg raise measurements were conducted by blinded examiners using a digital inclinometer. An independent samples t test was used to analyze changes in hamstring flexibility from pretreatment to posttreatment with P values set a priori at .05. Results: An independent samples t test demonstrated no significant difference in change in hamstring flexibility between participants in the treatment group and those in the control group (t23 = -.961, P = .35). Conclusions: The findings of this study demonstrated no statistically significant changes in hamstring flexibility following a cupping treatment.

Demographic and modifiable factors associated with knee contracture in children with cerebral palsy.

To identify the prevalence of knee contracture and its association with gross motor function, age, sex, spasticity, and muscle length in children with cerebral palsy (CP). Cross-sectional data for passive knee extension were analysed in 3045 children with CP (1756 males, 1289 females; mean age 8y 1mo [SD 3.84]). CP was classified using the Gross Motor Function Classification System (GMFCS) levels I (n=1330), II (n=508), III (n=280), IV (n=449), and V (n=478). Pearson's χ2 test and multiple binary logistic regression were applied to analyse the relationships between knee contracture and GMFCS level, sex, age, spasticity, hamstring length, and gastrocnemius length. Knee contracture greater than or equal to 5 degrees occurred in 685 children (22%). The prevalence of knee contracture was higher in older children and in those with higher GMFCS levels. Odds ratios (ORs) for knee contracture were significantly higher for children at GMFCS level V (OR=13.17), with short hamstring muscles (OR=9.86), and in the oldest age group, 13 years to 15 years (OR=6.80). Knee contracture is associated with higher GMFCS level, older age, and shorter muscle length; spasticity has a small effect. Maintaining muscle length, especially of the hamstrings, is important for reducing the risk of knee contracture. Knee contracture occurs in children with cerebral palsy at all Gross Motor Function Classification System (GMFCS) levels. Knee contracture in children is associated with short hamstring muscles, higher GMFCS level, and older age. Short hamstring muscles present a greater risk for knee contracture than spasticity.