to will not discuss off label use and/or use in our · • maintain contralateral hip in flexion to...

AACPDM IC#21 DFEO+PTA 1

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 InformationAACPDM 70th Annual Meeting | September 20‐24, 2016

Disclosure of Relevant Financial RelationshipsWe have the following financial relationships to disclose:

Research support from: Gait & Motion Outcomes Fund, Gillette Children’s Specialty Healthcare

Liz Boyer, PhD

No Financial Relationships to Disclose

Jean Stout, PT, MSKatie Walt, PT, DPTLibby Weber, MD

Tom Novacheck, MD

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 minSurgical Techniques Libby Weber 10 minPost‐Operative Rehabilitation Katie Walt 15 minQuestion & Answers 5 minBreak 10 minInsights Based on Review of Complications Jean Stout 15 minWhat About the Hamstrings Libby Weber 10 minPatellar Position Post DFEO+PTA Tom Novacheck 10 minLong Term Outcomes: Case vs. Control Liz Boyer 15 minQuestion & Answers 5 min


PRINCIPLES & BIOMECHANICAL MODELS OF CROUCH AND DFEO+PTA

Tom Novacheck, MD

Crouch Gait and DFEO/PTAin Cerebral Palsy:

Principles & Biomechanics

Tom F. Novacheck, MDPediatric Orthopaedic Surgeon

Director, James R Gage Center for Gait and Motion AnalysisSt. 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


Crouch Kinematics

• 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

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


Hamstrings in crouch gait

pelvis

thigh

tibia

foot

pelvis

thigh

tibia

foot

Anterior pelvic tiltHamstrings long

Posterior pelvic tiltHamstrings short

Muscle lengths – origin to insertion

(40°)Unilateral Popliteal Angle

• Lying supine, flex the ipsilateralhip to 90while 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.

Bilateral Popliteal Angle

• 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.

(10°) 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?


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 DiseaseThe

Plantarflexion/ Knee Extension

Couple


Normal Crouch

Crouch = loss of PF/KE couple

One joint muscles are long!

Two joint muscles may be short.

Crouch Older patient

• Knee flexion contracture

• Knee extensor insufficiency

Knee contracture (0°)

• Check to see if you can passively extend the knee.

Biomechanics of DFEO

• 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)


The difference between the active range and the passive range of motion during knee extension.

Extensor Lag (30°)

• 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

• 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

Biomechanics of PTA

• 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


Short Term Outcomes

Distal Femoral Extension Osteotomy and

Patellar Tendon Advancementto Treat Persistent Crouch Gait in Cerebral Palsy

90:2470-2484. JBJS-A 2008

Stout JL, Gage JR, Schwartz MH, Novacheck TF

Methods – Subjects

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

Pre‐ and post‐operative 3‐D gait analysis

Measurement of patellar height (Koshino Index*)

Functional Outcome (Gillette FAQ & PODCI)

Energy Assessment (metabolic O2)

One‐way ANOVA Paired t‐tests

* Koshino et al. JPO, 1989

Results

Seventy‐three individuals, 116 sides.

• 51 DFEO+PTA

• 22 DFEO‐Only

• 43 PTA‐Only

Average age: 13.9 years (10.0 ‐ 30.25)

Average follow‐up: 1.06 years (0.58 ‐ 2.08)

89% had additional concurrent surgery


Technical Outcome ‐‐ Radiographic

DFEO+PTA

DFEO only

PTA only

Crouch improved, but persistent Contracture improved, but persists

Crouch correctedROM improved Contracture corrected

Crouch corrected No contracture 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


SURGICAL TECHNIQUE

Libby Weber, MD

A

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


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


Prop the foot on a stack of towels to reduce

Remove Chisel, insert plate

Verbrugge to shaft

PTA: What you need

Approach

‐Anterior approach to the knee

‐Patellar tendon may be redundant

‐Leave enough room distally for tendon advancement


1 2

3 4


• Provisional fixation•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

•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 tibialtubercle 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


• 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

to will not discuss off label use and/or use in our · • maintain contralateral hip in flexion to...

Documents