Acquired extension contracture of infancy or childhood.Less common than flexion contracture.F > MInitially thought to be congenital, or secondary to progressive idiopathic fibrosis of the vastus intermedius muscleNearly all children, H/O serious illness in early infancy.
ETIOLOGYRepeated IM inj in thigh during infancy.Antibiotic, analgesics, antiepileptic.AbscessMuscle traumaUnited fracture.
PATHOPHYSIOLOGYVolume of drug inj in to young babies compresses the capillaries & muscle fibres M. ischaemia fibrotic changes.Local M. necrosis at the site of inj.Irritative nature of the drug.Combined with severe underlying disease, poor nutrition & prolonged recumbency.
Muscle fibrosis adherent to bone & deep fascia dimple.Muscle fails to develop with the bone flexion becomes more & more restricted.Delay between the inj & contracture always present.# femur – Q adherent to callus – limit flexion.
CLINICAL FEATURESPainless, progressive limitation of both active & passive knee flexion with an extension contracture.Affected knee is normal at birth.Parents note the child’s difficulty in squatting, kneeling, sitting cross-legged, running, or climbing stairs.Walks with limp due to straight knee or unstable quadriceps gait.
Dimple , which deepens with forced flexion of knee.ROM; Painless in the available arc.Atrophy of thigh, absence of creases.Subcutaneous hardness.Genu- recurvatum in severe casesHigh riding patella.Habitual dislocation P in chronic case.
X rayContracture – progressive displacement & hypoplasia of patella, fragmentation of inf. Pole of patella.Skeletal changes in distal femur articular surface points anteriorly.Femoral condyles gets flattened.Tibial dislocated anteriorly.Gross degenerative changes.
Differential diagnosisC. genu recurvatum, Arthogryposis cong. Short Q, present at birth @ with other deformities.Cong. & habitual dislocation patella Q mech is relatively short, ROM not affected.Polio, myelomeningocele & NM disorders – unbalanced Q action – extension deformities.
TREATMENTEarly recognisation & prevention through passive ex. in children receiving intramuscular inj.Physio / passive stretching ex [doubtful use]Always surgical release is necessary.Indicated to prevent late changes in the condyles & patella.
Structures in contracture [Nicoll]1) fibrosis of the vastus intermedius muscle tying down the rectus femoris to the femur in the suprapatellar pouch and proximally,2) adhesions between the patella and the femoral condyles,3) fibrosis and shortening of the lateral expansions of the vasti and their adherence to the femoral condyles, and4) actual shortening of the rectus femoris muscle
Sengupta – proximal releaseDuring early stagesWhen no significant jt changes occurredPrinciple –fibrosed muscles is in the upper lateral part of thigh [inj]Upper attachment of V.L is detached from its origin after transversely cutting the fibrosed IT band.Fibrosed V. intermedius is erased from the femur.
Rectus femoris if fibrosed also to be released from its origin. Advantages:1. Eliminate extensor lag2. Hemarthrosis3. Performed at the site of the pathology4. Postoperative mobilisation is quicker5. High scar produces a more acceptable cosmetic result.
Thompson - Quadricepsplasty When there is more extensive changes success depends on1) whether the rectus femoris muscle has escaped injury,2) how well this muscle can be isolated from the scarred parts of the quadriceps mechanism,3) how well the muscle can be developed by active use.
Rectus muscle released from vasti on both sidesFibrotic V. intermedius partially excised.Intra-articular adhesions removed.Vasti are sutured with rectus keeping knee flexed.Rectus if contracted is elongated by V-Y plasty.
Postopknee was immobilised in plaster at 50* for 2-3 days.The knee then placed in a CPM.This was followed by intensive physiotherapy.Stretching ex are continued throughout the growing period.
Supracondylar femoral osteotomy – when genu recurvatum with degenerative changes developed in order to gain flexion.Arthrodesis – if arthritis symptoms are severe.