Roles of Distal Femoral Extension Osteotomy and Patellar Tendon Advancement in the Treatment of Severe Persistent Crouch Gait in Adolescents and Young Adults with Cerebral Palsy Instructional Course #21 Tom F. Novacheck, MD, Liz Boyer, PhD, Jean Stout, PT, MS, Katie Walt, PT, DPT, Libby Weber, MD Disclosure Information AACPDM 70 th Annual Meeting September 20 24, 2016 Disclosure of Relevant Financial Relationships We have the following financial relationships to disclose: Liz Boyer, PhD Research support from: Gait & Motion Outcomes Fund, Gillette Children s Specialty Healthcare No Financial Relationships to Disclose Tom Novacheck, MD Libby Weber, MD Jean Stout, PT, MS Katie Walt, PT, DPT We will not discuss off label use and/or investigational use in our presentation Severe Persistent Crouch Gait Course Objectives & Schedule Principles & Biomechanics of Crouch & DFEO+PTA Tom Novacheck 20 min Surgical Techniques Libby Weber 10 min Post Operative Rehabilitation Katie Walt 15 min Question & Answers 5 min Break 10 min Insights Based on Review of Complications Jean Stout 15 min What About the Hamstrings Libby Weber 10 min Patellar Position Post DFEO+PTA Tom Novacheck 10 min Long Term Outcomes: Case vs. Control Liz Boyer 15 min Question & Answers 5 min AACPDM IC#21 DFEO+PTA 1
Crouch Gait and DFEO/PTA in Cerebral Palsy: PRINCIPLES & BIOMECHANICAL MODELS OF CROUCH AND DFEO+PTA Tom Novacheck, MD Principles & Biomechanics Tom F. Novacheck, MD Pediatric Orthopaedic Surgeon Director, James R Gage Center for Gait and Motion Analysis St. Paul, MN, USA Associate Professor, Univ of MN Dept of Orthopaedic Surgery Etiologies of crouch gait Many possible contributing factors Hamstring spasticity Hamstring contracture Hamstring shift Lever arm dysfunction Insufficient plantarflexion/knee extension couple Knee flexion contracture Knee extensor insufficiency Weakness Motor control deficits Balance Sensory perception What is crouch gait? Visual Exam Excessive knee flexion in stance AACPDM IC#21 DFEO+PTA 2
Lack of knee extension terminal swing excessive knee flexion in stance @ IC, MS, TS Other pelvic tilt posterior vs. anterior? Ankle equinus vs. excessive dorsiflexion Crouch Kinematics Constant knee extension moment in stance due to crouch position (GRF posterior to knee joint) Quadriceps EMG Jump Gait Insufficient knee extension in terminal swing Excessive knee flexion in loading response Adequate knee extension in mid and terminal stance Excessive extension moment in LR Not a constant knee extension moment in stance Hamstrings AACPDM IC#21 DFEO+PTA 3
pelvis Hamstrings in crouch gait Anterior pelvic tilt Hamstrings long thigh tibia pelvis Posterior pelvic tilt Hamstrings short thigh tibia Unilateral Popliteal Angle (40 ) Lying supine, flex the ipsilateral hip to 90 while allowing the knee to bend to 90. Extend knee slowly until resistance is felt or opposite hip lifts up from the mat. Measure the degrees from the vertical. foot foot Muscle lengths origin to insertion Bilateral Popliteal Angle (10 ) Lying supine, align the ASIS PSIS vertically. Maintain contralateral hip in flexion to stabilize the pelvis in this position. Position the ipsilateral hip in 90 of flexion and the knee in 90 of flexion. Extend the knee slowly until resistance is felt or the opposite hip lifts up from the mat. Measure the angle from the vertical. Crouch associated with hamstring contracture Gait by observation posterior pelvic tilt/flat back shortened step length Exam popliteal angle, unilateral and bilateral (flatten lumbar lordosis by flexing opposite leg) limited hip flexion knee flexion contracture? AACPDM IC#21 DFEO+PTA 4
Hamstrings Muscle Length and Velocity Role of the Hamstrings in Crouch Gait hamstrings get longer/faster and knee extension improves with appropriate surgery risk of worsened pelvic tilt with hamstring lengthening if hamstrings are long pre op Lever Arm Disease The Plantarflexion/ Knee Extension Couple AACPDM IC#21 DFEO+PTA 5
Crouch Older patient Crouch = loss of PF/KE couple Two joint muscles may be short. Normal Crouch Knee flexion contracture Knee extensor insufficiency One joint muscles are long! Knee contracture (0 ) Biomechanics of DFEO Check to see if you can passively extend the knee. Knee flexion contracture on physical exam (typically 10-30 ) Goal -- achieve full passive knee extension Note: create an extension deformity of the distal femur to compensate for knee joint contracture (capsular) AACPDM IC#21 DFEO+PTA 6
Extensor Lag (30 ) The difference between the active range and the passive range of motion during knee extension. Position the patient supine with lower legs over the end of the mat. Flex one knee to eliminate a total extension pattern. Ask patient to straighten the free knee as far as possible. Extensor Lag testing position critical to discount hamstring tightness as a factor often seen in conjunction with patella alta may give insight into etiology of crouch gait despite good muscle strength midrange Screening for Patella Alta Biomechanics of PTA To screen, position patient supine with knees extended. Palpate the top of the patella. The superior edge of the patella is typically one finger width proximal to the adductor tubercle Indication extensor lag on PE (end ROM quad insufficiency) if a DFEO has been performed Goal -- optimize quadriceps length and function to maintain active knee extension during stance AACPDM IC#21 DFEO+PTA 7
Short Term Outcomes Methods Subjects Distal Femoral Extension Osteotomy and Patellar Tendon Advancement to Treat Persistent Crouch Gait in Cerebral Palsy 90:2470-2484. JBJS-A 2008 Stout JL, Gage JR, Schwartz MH, Novacheck TF Adolescents & young adults with a diagnosis of cerebral palsy who had undergone the following procedures: i) distal fem ext osteotomy with patellar tendon advancement (DFEO+PTA) ii) distal femoral extension osteotomy (DFEO only) iii) patellar tendon advancement alone (PTA only) Inclusion Criteria & Analysis Results Pre and post operative 3 D gait analysis Measurement of patellar height (Koshino Index*) Functional Outcome (Gillette FAQ & PODCI) Energy Assessment (metabolic O2) Seventy three individuals, 116 sides. 51 DFEO+PTA 22 DFEO Only 43 PTA Only Average age: 13.9 years (10.0 30.25) One way ANOVA Paired t tests * Koshino et al. JPO, 1989 Average follow up: 1.06 years (0.58 2.08) 89% had additional concurrent surgery AACPDM IC#21 DFEO+PTA 8
Technical Outcome Radiographic DFEO only Crouch improved, but persistent Contracture improved, but persists DFEO+PTA Crouch ROM Contracture corrected improved corrected PTA only Crouch No contracture corrected pre op Patellar Tendon Advancement Necessary to achieve optimal results of persistent crouch gait in isolation with DFEO (if knee contracture) Remember to take care of the rectus femoris! Transfer Selective Dorsal Rhizotomy Typical Scenario for DFEO/PTA Peri-adolescent or young adult Crouch gait despite prior treatment typically including failed prior hamstring lengthening Weak ankle plantarflexors Pain and patellar stress fractures common not the primary indications for surgery AACPDM IC#21 DFEO+PTA 9
SURGICAL TECHNIQUE A Libby Weber, MD B DFEO: What you need Pre operatively: assess need for: Varus or Valgus correction Torsional correction Mark the growth plate and the joint line Guide wire placed parallel to blade held against femoral shaft AACPDM IC#21 DFEO+PTA 10
Lateral approach to the distal femur Chisel and alignment guide Cuts TIPS Large Chandler or Cobra retractors Long saw blade Metaphyseal bone Complete cut Finish if necessary with osteotome Lamina spreader may be helpful in removing the bone wedge Score the bone or place pins to control rotation Occasionally there is a posterior prominence consider removing spike if large AACPDM IC#21 DFEO+PTA 11
Prop the foot on a stack of towels to reduce PTA: What you need Remove Chisel, insert plate Verbrugge to shaft Approach Anterior approach to the knee Patellar tendon may be redundant Leave enough room distally for tendon advancement AACPDM IC#21 DFEO+PTA 12
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Fiber tape passed through a drill hole in the tibia placed at the distal extent of the incision (2.5 drill) with a suture passer Provisional fixation With knee straight, patella is pulled to new desired position (distal tip at tibial spines) **This may not take much effort or tension avoid over tightening Tie fiber tape to maintain that position What s different for the skeletally mature? Without an open growth plate the guide wire and plate can be placed more distally AGAIN make sure not to introduce valgus as plate approaches the metaphyseal flare What s different for the skeletally mature? With a closed tibial tubercle apophysis the tendon can be taken as a bone block. A second bone block is taken as a recipient site and moved proximally for graft AACPDM IC#21 DFEO+PTA 14
4.5 screw to secure the tendon to its new location Be wary of being long with the screw Be wary of the monster bite This screw can be symptomatic and may have to be removed in the future AACPDM IC#21 DFEO+PTA 15