Dislocation of the hip joint Three types of hip dislocation : - 1 . Anterior dislocation ( 10 – 15 %) 2 . Posterior dislocation ( 70 % ) 3 . Central dislocation ( rest )

Hip joint

Posterior dislocation of hip Common in the hip joint ( 70 % ) Mechanism of injury : Dashbroad injury as in RTA Simple dislocation : - Flexed knee + neutral adduction Fracture dislocation : - flexed knee + slight abduction

Mechanism that causes the majority of dislocations is impingement (to strike )of the neck of the femoral component against the rim of the cup.

Pipkin Fracture I - Posterior dislocation of the hip with fracture of the femoral head caudad to the fovea centralis II - Posterior dislocation of the hip with fracture of the femoral head cephalad to the fovea centralis III - Type I and type II with associated fracture of the femoral neck IV - Type I, II, or III with associated fracture of the acetabulum

Femur bone showing fovea centralis

Clinical features Limb shortening Flexion , adduction and medial rotation deformity of the affected limb Thigh rest on the contralateral limb Head felt in the gluteal region Movement of hip decrease Feature of sciatic nerve palsy

Feature of sciatic nerve palsy SCIATICA or pain localized to the hip, PARESIS or PARALYSIS of posterior thigh muscles and muscles innervated by the peroneal and tibial nerves, sensory loss involving the lateral and posterior thigh, posterior and lateral leg, and sole of the foot. Pain when sitting, sneezing or coughing tingling sensation or numbness down the leg Foot drop

Fig:- Foot drop

Radiology X – ray AP and Lateral view of the pelvis showing both the hip joints CT scan and MRI ( for acetabular fracture)

Treatment Closed reduction ( to reduce pain ) : - Four methods of closed reduction : - 1 . Stimson`s method : - Position : prone , at the edge of the table An assistant stabilizes the pelvis Physician applies downward pressure on the calf with one hand while applying external rotation to the femur.

2 .Allis traction 3 . Bigelow`s method: - Position : supine An assistant stabilizes the pelvis The physician simultaneously distract (to pull away ) the femur and rocks it medial to lateral . 3 . Bigelow`s method: - Physician applied upwards traction on the femur while an assistant stabilize the pelvis 4 .Classical watson`s – jones method : - Limb is brought to the neutral position first then longitudinal traction in the of femur is given.

After treatment After reduction , the patient is put on a skin traction or immobilised in a Thomas split for 3 weeks . Full weight bearing after 6 weeks . Indication of open reduction : - 1 . Failure of close reduction : due to obstruction by bony fragments or by soft tissues . 2 . Instability after reduction 3 . Sciatic nerve palsy

Complications Early : - Late : - Sciatic nerve palsy Irreducible fracture dislocation Missed knee injuries Recurrent dislocation Late : - Myositis ossificans Avascular necrosis of bone Post – traumatic arthritis Unreduced posterior dislocation