AbstractAninferior hip dislocation with ipsilateral subtrochanteric fracture is anextremely rare occurrence. It is mostlydue to high energy trauma. We report a case of right traumatic inferior hip dislocationassociated with closed subtrochanteric fracture and contralateral closed distalthird femur shaft fracture.
Closed reduction was performed with joystickmaneuver using a Schantz screw percutaneously into the femoral neck undergeneral anesthesia. Subsequently the ipsilateral and contralateral femurfractures were fixed in a standard manner with cephalomedullary nail andretrograde interlocking nail respectively. Postoperatively no traction wasapplied and patient was advised for wheelchair ambulation. To our knowledge,this is the second reported case of an adult traumatic inferior hip dislocationwith ipsilateral closed subtrochanteric femur fracture. Keywords: inferior hip dislocation,ipsilateral subtrochanteric fracture, closed reduction, traumaticIntroductionInferiorhip dislocation or Luxatio erecta is an extremely rare injury with very fewcases being reported in English literature. Inferior hip dislocation withipsilateral subtrochanteric fracture is even rarer. It is commonly associatedwith high energy trauma.
Inferior hip dislocation is further grouped into twotypes based on the injury mechanism: ischial and obturator. We report an adultcase of right traumatic inferior hip dislocation of obturator type associatedwith ipsilateral closed subtrochanteric fracture and contralateral closeddistal femur shaft fracture. To our knowledge there is only one previous reported inferior hip dislocation associatedwith ipsilateral subtrochanteric femur fracture5.Case reportA22-year-old man presented to our centre after a motor vehicle accident(motorcycle versus car). Due to transient loss of consciousness, patient couldnot recall the mechanism of injury. After trauma he complained of pain overright proximal and left distal thigh. Right lower limb was externally rotatedwith the hip and knee flexed.
Left distal thigh was swollen and tender. Neurovascularstatus of both lower limbs was otherwise intact. Ananteroposterior and lateral hip radiograph showed inferior dislocation of righthip with ipsilateral displaced subtrochanteric fracture. Left femur radiographrevealed a distal third femur fracture.
Computed tomography (CT) showedimpingement of right femoral head by the inferior acetabular lip (Figure1). Closed reduction was attempted oncein emergency department under sedation however we failed to reduce thedislocated hip. The patient was then brought to operating room where a 5mmSchantz screw was driven percutaneously through the posteroinferior portion ofthe right femoral neck and the hip was reduced by traction and externalrotation under general anesthesia in supine position (Figure 2). Stability was assessed in all planes ofmotion and verified with image intensifier. Theright subtrochanteric femur fracture was subsequently stabilized and fixed witha cephalomedullary nail in a standard manner through lateral approach.
Thestability of reduction was confirmed under image intensifier and was found tobe satisfactory. The left femur fracturewas reduced and fixed with a retrograde intramedullary nail. The patient wasdischarged uneventfully with non-weight bearing ambulation for 6 weeks.DiscussionInferiorhip dislocation is a very rare injury. Until 2015, only ten cases had beenreported amongst adults3.With exception of one publication reporting a traumatic inferior hipdislocation with ipsilateral open subtrochanteric fracture, there is no otherliterature documenting a case with similar presentation5. Brogdon and Woolridged described two types ofinferior hip dislocation associated with two different mechanisms of injury:the ischial and obturator type2.
The ischial type is characterized by the femoral head dislocating inferiorlyand lying next to the ischium. It is more common and is a result of a forceapplied to the flexed hip and knee, with the femur in extreme flexion. The obturator type involves a force appliedto the abducted hip followed by flexion and external rotation to dislocate thefemoral head which lies anterior and inferior to the obturator forame. Theobturator type is rarer than the ischial type.Inthe diagnosis of inferior hip dislocation, CT is advisable to evaluate the typeof inferior hip dislocation and other associated injuries such as acetabularand head of femur fractures without delaying the joint reduction.
It also aidsin determining the treatment approach and prognosis. Althoughit is difficult to achieve closed reduction with concurrent ipsilateral femurfracture, it should still be attempted to reduce the risk of avascular necrosisof femoral head. In addition, open reduction might further jeopardize thevascular supply to the femoral head which is disrupted by the traumatic hipdislocation.
In this case, closed reductionwas attempted first in the emergency department followed by hip reduction usingSchantz screw driven percutaneously in the operating theatre. We believe thedifficulty in closed hip reduction was partly contributed to by the obturatortype of inferior hip dislocation where the sharp anterolateral margin of theobturator foramen might impinge the anterosuperior part of femoral head. Inaddition, with the concurrent ipsilateral subtrochanteric femur fracture,proper longitudinal traction could not be applied to reduce the dislocatedproximal femur. Our case showed that hip reduction using Schantz screw drivenpercutaneously offers a better technique to reduce the dislocated hip withipsilateral femur subtrochanteric fracture.Todate there is no neurovascular complication reported following inferior hipdislocation1.
Development of femoral head avascular necrosis is not associated with postoperative rehabilitation or weight bearing4.The time interval from injury to reduction matters. For our present case,wheelchair ambulation was initiated as patient had bilateral femur fracture. ConclusionInferiorhip dislocation with concomitant ipsilateral subtrochanteric fracture isextremely rare with only one case reported previously. An early diagnosiseither clinically or radiologically is essential for prompt reduction to reducethe risk of femoral head avascular necrosis.
Closed reduction with percutaneous Schantz screw is recommended undergeneral anesthesia followed by definitive fixation.