Short-term Hardware Outcomes Following Patellar Tendon Advancement in Pediatric Patients with Crouch Gait Authors Institutions

Introduction Cerebral Palsy: motor syndromes - 2° to brain development Crouch gait – spasticity/contracture Hamstring/psoas tightness Lever-arm dysfunction Weakness Impaired balance Cerebral palsy (CP) is a diagnostic term used to describe a group of motor syndromes resulting from disorders of early brain development. CP is caused by a broad group of developmental, genetic, metabolic, ischemic, infectious, and other acquired etiologies that produce a common group of neurologic phenotypes. CP is the most common and costly form of chronic motor disability that begins in childhood with a prevalence of 2/1000. Kliegman, Robert M., Richard E. Behrman, Hal B. Jenson, and Bonita F. Stanton. Nelson Textbook of Pediatrics. Philadelphia: Saunders, 2007.

Crouch Gait Body Mechanics Knee and back pain Quadriceps insufficiency Knee flexion Hip flexion Ankle dorsiflexion Knee and back pain Quadriceps insufficiency Patella alta & Elongation of patellar tendon 2° to achilles tendon lengthening The loss of an adequate plantar flexion/knee extension couple keeps the ground reaction force behind the knee joint and in front of the hip and ankle joint. Fixed knee-flexion contractures often develop. Patella alta and elongation of the patellar tendon develop over time and become contributing factors. Knee pain, probably related to the increased quadriceps forces required to stabilize the flexed knee joint, increased patellofemoral compressive forces, and/or eventual patellar pole or tibial tubercle fracture, frequently develops as well. Anterior subluxation can be associated with crouch gait. Knee and back pain have been mentioned as two of the primary factors that limit or decrease the walking ability of these patients. When present, quadriceps insufficiency and fixed knee-flexion contractures contribute to crouch gait. Chambers Eur J Neur 2001 Stout et al. JBJS 2008

Treatment Gait analysis for evaluation (Pre-op Mov?) Conservative Occupational/Physical therapy Assistive devices Medical Muscle relaxants Benzodiazepines Botulinum toxin Treatment for crouch gait generally involves a kinematic analysis of gait for quantitative assessment. Conservative treatments include: OT/PT: ADLS--- prevent contractures, strength conditioning, stretching, movement Assistive Devices: walkers, poles, standing frames etc… Medical therapies: (to treat spasticity) -muscle relaxants – dantrolene orally, baclofen orally or intrathecal -Benzos -Botulinum Toxininjected into specific muscle groups Kliegman, Robert M., Richard E. Behrman, Hal B. Jenson, and Bonita F. Stanton. Nelson Textbook of Pediatrics. Philadelphia: Saunders, 2007.

Surgical Treatment Procedures typically done (Get from Halanski) (Preop and postop x-rays) (Preop/postop gait analysis) Possibly describe what procedures are typically done. Patellar tendon advancement: Patellar tendon is excised from the tibial tuberosity. Transverse lumen is drilled through the patella and on the tibia distal to the tibial tuberosity. Cercalage wire/cable is passed through the patella and proximal tibia. Patellar tendon is transected with the leg in extension and the shortened tendon is reinserted onto the tibial tuberosity with suture. Cercalage wire/cable is secured into place to provide mechanical support for the reinserted patellar tendon.

Crouch Gait Pre and post-op radiographs of a patient with crouch gait. Treated with distal femoral osteotomy and patellar tendon advancement. (Get surgical report at butterworth) Describe procedure

Surgical Treatment Distal femoral extension osteotomy Patellar tendon advancement Patellar insertion freed Patellar tendon advanced distally along tibia - Cercalage wire from patella to insertion Stabilize new insertion Combination REITERATE THE OBJECTIVE: To examine the short-term outcomes of hardware failure following patellar tendon advancement in patients with crouch gait using a cercalage wire versus a cercalage cable for patellar tendon stabilization. Stout et al JBJS 2008

Objective To examine the short-term outcomes of hardware failure following patellar tendon advancement in patients with crouch gait 2 Hardware types - Cercalage cable - Cercalage wire

Methods Retrospective cohort study radiographs Inclusion Criteria Billing codes: patellar advancement Helen DeVos Children’s Hospital 1/1/03 to 11/2/08 Exclusion criteria Different procedure performed Age > 17

Methods Patient radiographs Patient records Fisher’s exact test Cercalage wire vs. cable Failure vs. Intact Patient records Age at procedure Time to post-op radiograph Time to failure Fisher’s exact test

Radiographs Cercalage wire Cercalage cable s/p surgery: wire vs. cable -wire secured manually -cable is clamped Mention differences in surgery in pictures – femoral extension osteotomy in the wire picture - Reiterate only focusing on the patellar advancement portion of the procedure

Hardware Failure Wire Failure at 117 Days: -notice that the patellar tendon is healed and that the patella is still advanced despite hardware failure -requires a 2nd surgery to remove hardware secondary to discomfort

Results 16 Patients with 31 Patellar advancements Fisher’s exact T-test (p < 0.001) Hardware Wire Cable Age (years) 13 10 # Performed 11 20 # Failed 9 Failure Rate 89% 0% Avg. Time F/U 258 90 Overview of study numbers: Wire Follow-up: -258 days average until FAILURE Cable Follow-up: -90 day average TOTAL FOLLOW-UP Need to wait until we can get the same average follow-up time for both groups.

Discussion Statistically significant advantage to cables Shorter follow-up time Continued observation cables 1 year follow-up

Conclusion Cables show better outcomes than wires 1 year follow-up for recommendations Possible implications Decrease failed hardware removal More rapid mobilization post-op Reference

Future Work Continue follow-up for > 1 year Evaluation of long-term hardware outcomes Evaluation of patellar advancement on growth plate mechanics Evaluation of gait kinematics Reference

Acknowledgments Attending Editor Statistician Institution