Purpose of the study: Spasticity of the rectus femoris (RF) in cerebral palsy patients is considered to be the main cause of stiff knee gait. The kinematics of this muscle, variations in length and speed of lengthening, are altered. Research is however lacking on changes in this parameter after surgery. Our objective was to study its effect on the quality of gait and on the kinematics of the RF in order to identify kinetic behaviour with diagnostic value.

Material and methods: Twenty-six transfers were performed during multiple level interventions. A uniform technique was applied: wide separation of the RF from the vastus muscles and supra-patellar tenotomy, suture of the RF tendon to the gracilis tendon tunnelled through the medial intermuscular partition. Intramuscular lengthening of the hamstrings (n=20) was associated with patella lowering procedures (n=4). The Gait-Deviation-Index (GDI) and the Goldberg score were determined pre- and postoperatively to quantify gait quality and search for stiff knee. A musculoskeletal model (virtual RF) was developed to simulate the trajectory of the RF during gait.

Results: The quality of gait improved (+18±12 GDI) with a negative interaction between the preoperative GDI and its improvement. For the Goldberg score, surgery yielded 88% improvement. Surgery had a significant effect on normalising the timing of RF lengthening and the maximal lengthening speed. Improvement in stiff knee was correlated with a normalisation of the timing of maximal length.

Discussion: Improvement in gait quality was greater when the preoperative quality is low; there is a risk of no improvement if the GDI is > 75. Normalisation of the timing of the maximal length of the RF is correlated with improvement in knee oscillation. Early timing signals a postoperative improvement in stiff knee. Early peak in the speed of lengthening of the RF can be explained by early triggering of spasticity during weight bearing which would limit the lengthening of the RF.

Conclusion: Global improvement of gait quality and stiff knee has been demonstrated. Certain muscular kinematic parameters are normalised, demonstrating the effect of transfer during oscillation but also during weight-bearing. Early peak in RF lengthening is a prognostic factor of successful surgery.

Purpose of the study: Variations in patellar height in relation to the trochlea and the joint line can be a cause of pain and instability and limit the range of knee flexion. The Caton and Deschamps index (CDI) was described and validated in a cohort of adult subjects. The purpose of this work was to validate this index and set the reference values in a paediatric population.

Material and methods: Lateral view of the knee were obtained in 300 patients who consulted for minor trauma without ligament or bone injury. Thirty patients, aged 6 to 15 years, were included in each age group (1-year groups). All radiographs were qualified as normal by the radiologist. Two series of measures were made in random order and at an interval of 8 days by two independent observers. The patellar height and the length of the patellar tendon were measured with computer assistance. The interob-server and intraobserver variabilities were determined.

Results: The mean patellar height was 33.39±7.40 mm. The mean length of the patellar tendon was 34.57±67.36 mm. The mean CDI was 1.06±0.21. There was not significant correlation between patient age, height of the patella and length of the patellar tendon. Thus the height of the patella and the length of the patellar tendon increased with age while the CDI was statistically lower in older patients. The height of the patella was identical in the two genders while the patellar tendon was statistically longer in boys. The CDI was statistically higher in boys. Interobserver and intraobserver agreement was excellent.

Discussion: CDI is a simple and reproducible measurement in adults and in children and adolescents. During growth, it is an alternative to the Insall index which has limited reproducibility and the Koshino index which is difficult to use in routine clinical situations. We found a correlation between CDI and children’s age, related to progressive ossification of the patella.

Conclusion: The CDI is a tool which can be used in routine practice to study patellofemoral problems in the paediatric population as long as the physiological values are weighted by age.

Purpose of the study: The posterior paraspinal approach to the lumbar spine was initially described and promoted by Wiltse for posterolateral arthrodesis of the lumbosacral junction in patients with spondylolisthesis. Despite technical improvements proposed by Wiltse, the muscular cleavage is still poorly localized in the sacrospinalis muscle. The purpose of this work was to provide a more accurate anatomic description of this spinal approach and to describe anatomic landmarks to facilitate execution of the procedure.

Material and methods: Fifty anatomic specimens were dissected (27 male and 23 female cadavers); 33 had been embalmed. The anatomy study used a bilateral approach to the spine. The exact anatomic localization of the muscle cleavage was noted. Measures were taken in relation to the mid line of the L4 spinatus process.

Results: In all specimens, the muscle cleavage lay between the multifidus and longissimus heads of the sacrospinalis muscle. A fibrous partition was noted in 88 of the 100 specimens. The mean distance from the mid line to the cleavage line was 4.04 cm (range 2.4–7.0 cm). The surface of the sacrospinalis muscle presented fine perforating arteries and veins in all specimens, directly in line with the cleavage plane. In 12 cases, a major posterior sensorial branch of the L3 nerve running to the skin was identified in the cranial portion of the approach.

Discussion: The muscle cleavage plane appears to be easy to localize for the paraspinal approach to the lumbosacral junction. Opening the aponeurosis of the latissimus dorsi near the mid line enables visualization of the perforating vessels in line with the anatomic cleavage plane of the sacrospinalis muscle. In our experience, this plane is situated on average 4 cm from the mid line. Hemostasis of these vessels is acceptable since the sacrospinalis muscle has a rich supply of anastomosed vessels. Care must be taken to avoid injury to the posterior sensorial branch of the L3 nerve which runs along the plane of the muscle cleavage.

Conclusion: In our opinion, this minimally hemorrhagic approach is perfectly adapted to non-instrumented fusion of the lumbosacral junction, particularly for spondylolisthesis in children and adults. Precise knowledge of the anatomy of this approach is a necessary prerequisite for successful execution.

Purpose of the study: Equinus in patients with cerebral palsy results from at least two factors: excessive contracture of the triceps surae and muscle retraction. Tendon surgery and progressive lengthening techniques using plaster walking boots can provide variable improvement in retraction. We compared the effect of this technique when applied with or without prior 40°C warming in the same patients. We also assessed the efficacy of this treatment method in terms or degree of retraction, patient age, puberty maturity, and sex.

Materials and methods: This series included 70 muscles in 52 patients with cerebral palsy aged 2 years 11 months to 21 years (mean 8 years 3 months). Common features in these patients were: equinus mainly explained by triceps retraction, no history of prior surgery on the triceps tendon, knee flexion less than 15° in the upright position, easily reduced lateral deformation of the foot, absence of mediotarsal dislocation, triceps stretching could be achieved without triggering unacceptably intense contracture.

The retraction of the triceps surae was measured from the maximal passive dorsal flexion angle of the foot, before and after applying each stretching boot. The difference between these measurements gave the gain obtained with the plaster boot. Protocol R− (stretching with plaster boot) consisted in a series of slow stretchings for 10 minutes before making the boot which was worn 7 days. Recurrent retraction in these same patients warranted another treatment within a delay of 3 to 17 months (mean delay 8.7 months). The same treatment then followed protocol R+ where the stretching was preceded by immersion of the segment in a 40°C water bath for 10 minutes.

Results: Mean gain obtained with protocol R+ (warming) was 6.8° knee extended and 7.1° knee flexed. These differences were highly significant in both cases (p < 0.0001). We had no failures with protocol R+ while with protocol R− (stretching without warming) the gain was nil or less than 5° for 29 muscles knee extended and for 32 muscles, knee flexed. The gain was not related to age, sex or puberty maturity. It was not related to the angle of dorsal flexion of the foot prior to stretching.

Discussion: Our findings demonstrate that when the conditions allowing prolonged stretching of the triceps surae are present, prior warming at 40°C for 10 minutes leads to an improvement in muscle lengthening in all patients, even in those for whom prior treatment had been unsuccessful without warming. This observation would indicate that the mechanisms allowing greater lengthening are present in all patients with cerebral palsy but that they cannot be triggered due to abnormal muscle viscosity related to distal vasomotor disorders frequently observed in this condition. Further research is needed to detail this point.