1 Dislocation of the hip

2 It is of three main types :1- posterior type . 2- anterior type . 3- central type . four out of five traumatic dislocation of the hip is of posterior type .

3 Posterior hip dislocationIt is the commonest type of hip dislocation Mechanism of injury : It is occur in road traffic accident when some one seated in truck or car is thrown foreword striking the knee against the dashboard . The femur is thrust backward and the femoral head is forced out of its socket . Often a piece of bone of the acetabulum is sheared off making it a fracture – dislocation

4 Dashboard injury

5 Clinically : On examination the leg is short lies adducted , internally rotated and slightly flexed . This injury is easily to be missed when associated with fracture femur . The lower limb should be examined for sciatic nerve injury . X-ray : a-p view : the femoral head is seen out of its socket and above the acetabulum . There may be associated fracture in the femoral head or in the rim of the acetabulum .

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9 Treatment : Dislocation must be reduced as soon as possible under general anesthesia . The assistant steadies the pelvis , the surgeon start by applying traction in the line of the femur 90% flexion of both hip and knee , then a clunk terminate the maneuver . Followed by x-ray checking ; then put the injured limb in rest by applying skin or more beneficial skeletal traction for 3-6 weeks , the patient is allowed to walk by crutches ; if there is fracture rim of the acetabulum and the piece is large the internal fixation is mandatory .

10 Reduction of posterior dislocation of the hip

11 Complication : Early : 1- sciatic nerve injury : it is occur in10-20 % of the cases but fortunately it is usually recovered , if not , then nerve exploration . 2- vascular injury : superior gluteal artery . 3- associated fractures : acetabular , femoral head , femoral neck and femoral shaft and here the dislocation may be missed .

12 Late : 1- avascular necrosis of the femoral head : in any dislocation the vascularity is impaired about10% , if the reduction is delayed it may reached up to 40% . Avascular necrosis appear in the x-ray as an increase in density of the femoral head , but it is not seen before 6 weeks and some time up to 2 years . In early weeks , bone scan and MRI will be helpful in the diagnosis of ischemia .

13 Treatment of avascular necrosis :younger patient treated either by femoral head replacement or realignment osteotomy if it is partial or by arthrodesis of the hip . In older patient with acetabular changes then total hip replacement . 2- myositis ossificans . 3- unreduced dislocation : if after few weeks the dislocation is missed and not reduced , open reduction is mandatory 4- secondary osteoarthritis : and this due to : a- cartilage damage . B- retained fragment . C- ischaemic necrosis.

14 Anterior dislocation of the hipit is rare . Clinically : the leg is externally rotated , abducted and slightly flexed , not short . some time the lower limb is abducted to right angle . X-ray : a-p view , the dislocation is obvious , any doubt is resolved by lateral view .

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17 Central dislocation of the hipfall on the side or blow over the greater trochanter may force the femoral head medially through the floor of the acetabulum . Although it is called central dislocation of the hip , it is really a fracture of the floor of the acetabulum.

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19 Fractures of the femoral neckNeck of the femur is a commonest site of fracture in elderly . Risk factors : 1- osteoporosis . 2- osteomalascia . 3- diabetes mellitus . 4- stroke (disuse) . 5- weak muscles and poor balance . 6- alcoholism . 7- debilitating diseases .

20 Generally fracture neck femur is classified in to :A – intra capsular fracture neck of femur . B - extra capsular fracture neck of femur . A- intracapsular fracture neck of femur : Mechanism of injury : This fracture usually result from a fall directly on to the greater trochanter . In very osteoporotic patient less forced is required . Some time no more than catching a toe in the carpet and twisting the hip into external rotation . In young people the cause is mainly car accident or fall from height .

21 Classification : the most useful classificationintracapsular fracture neck of femur is that of (Garden classification) which based on the degree of displacement . Stage one : is incomplete impacted fracture . Stage two : is complete undisplaced fracture . Stage three : complete fracture with moderate displacement . Stage four : is severely displaced fracture .

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23 The blood supply of the head of the femur :1- intramedullary (metaphyseal) vessels in the femoral neck. 2- capsular vessels ; in the capsule of the joint . 3- the vessel in the ligamentum teres . The first two vessels are interrupted by the fracture and the third is present in only 20% of the population.

24 Blood supply of the femoral head

25 Intracapsular fracture neck of femur

26 Clinical feature : History of fall followed by pain in the hip . If the fracture is displaced , the limb will be externally rotated ,and short . Treatment : The first measure is to apply skin traction to splint the fracture and to control the pain , and give analgesic for pain relieve . Operative treatment is always mandatory . Displaced fracture will not unite without internal fixation . Old people should be got up and active without delay to avoid pulmonary complication ,bed sore ,DVT and other bed ridden complications .

28 Impacted fracture can be treated conservatively with traction to avoid displacement . But internal fixation is safer . The operation should be done as early as possible to avoid risk of complications . The principle is perfect reduction , secure rigid fixation and early mobilization . the fixation should be done by internal fixators like compression screws , plate and screws , dynamic hip screw ……etc . In patient above 60 with displaced fracture , partial hip replacement is indicated ; total hip replacement is indicated if the treatment is delayed or in metastatic disease .

29 Dynamic hip screw

30 Complications : General complication :Most of these patients are elderly , and they are prone to general complication such as : 1- deep vein thrombosis . 2- pulmonary embolism . 3- pneumonia . 4- bed sore .

31 1- a vascular necrosis of the femoral head .Local complication : 1- a vascular necrosis of the femoral head . It is occur in 30% of the displaced fracture , and in 10% of the undisplaced fracture . There is no way to diagnose avascular necrosis of femoral head immediately , but few weeks later we can diagnose it by bone scan MRI and later by x-ray . X-ray changes may not show it self for months or even years . whether the fracture unite or not there will be collapse of the femoral head and this will lead to pain , shortening of the limb and progressive loss of function .

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33 Avascular necrosis of the femoral head

34 Treatment of avascular necrosis :In patients over 45 years old , the treatment is by total hip replacement . Below this age , the treatment will be by realignment osteotomy . 2- non union : More than 30% of all femoral neck fracture fail to unite , and increase in displaced fracture

35 Avascular necrosis treated by total hip replacement

36 Causes of non union of femoral neck fracture :1- poor blood supply . 2- flimsy periostium. 3- inadequate fixation . 4- presence of synovial fluid (continuous wash of the fracture hematoma). Treatment : In relatively young patient : 1- rigid internal fixation and vascularised graft . 2-partial or total hip replacement .

37 Partial hip replacement

38 3- osteoarthritis of the hip joint .In elderly : Partial or total hip replacement . 3- osteoarthritis of the hip joint . Avascular necrosis of the femoral head will lead to osteoarthritis later on . The treatment is by total hip replacement .