Avascular Necrosis (AVN) of femoral head is most common in?
Ans. A. Intracapsular fracture neck of femur. (Ref. Maheshwari ortho 3rd/pg. 112; Current Ortho/ Ch.3.)Femoral Neck FractureIntroduction:# There are two types of of the neck of femur .Intracapsular &Extracapsular# Most of the Femoral neck fractures are intracapsular fractures (as a matter of convention, the term fracture of the neck of femur' is used for intracapsular fracture of the neck).# The extracapsular are usually called inter-trochanteric .Classification# A. Anatomical classification# B. Pauwel's classification# C. Garden's classificationGarden classification for acute fractures of femoral neck is the most widely used system:Garden classification for fractures of femoral neckType 1Valgus impaction of the femoral headType 2Complete but nondisplacedType 3Complete fracture, displaced less than 50%Type 4Complete fracture displaced greater than 50%c/f:# The involved extremity may be slightly shortened and externally rotated.# Tenderness in groin# Attempted hip movements painful, and asso with sever spasm# Active straight leg rising not possible.Complications:# 1. Non-union (in 30-40% of IC ).# 2. AVN: high risk of nonunion or avascular necrosis of the femoral head due the unusual vascularization of the femoral head and neck. The incidence of avascular necrosis increases with the amount of fracture displacement and the amount of time before the fracture is reduced.# 3. OARx:# This is rightly termed as "unsolved " because of the high incidence of complications.# This invariable needs operative Rx.# An impacted fracture is Rxed conservatively in all age groups (hip spica in childen and Thomas splint in adults).# Unimpacted or displaced fracture:- < 60 yrs: internal fixation.- > 60 yrs: head excised and replaced by prosthesis done as a primary procedure.- In few younger patients, especially if preesenting late, open reduction of is done.- Internal fixation can be done using any of the following implant:# Multiple cancellous screws - most commonly used.# Dynamic hip screws (DHS)# Multiple Knowle's pins/More's pins - used in children.# SP nail - not popular now.- At some centres in general an inter-trochanteric osteotomy (McMurray's osteotomy is preferred).- Hemiarthroplasty is used for elderly patients & Austin Moore prosthesis is used most commonly. This cannot be used as a method of Rx in younger patients as prosthesis becomes loose over a period of time (8-10 yrs).Meyer's procedure ( reduced by exposing it from behind and it is fixed with multiple screws and supplemented with vascularised muscle pedicle bone graft). It is used in treating the fractures presenting late and those with significant communition. It is also used for non-union of the femoral neck .Additional Educational points:The vascular supply of the femoral head is also of paramount importance. There are three main sources of vascular supply:1) The retinacular vessels arising from the lateral femoral circumflex artery and the inferior metaphyseal artery and then running beneath the synovium along the neck, which they penetrate proximally both anteriorly and posteriorly;2) The interosseous circulation crossing the marrow spaces from distal to proximal; and3) Unreliably, the ligamentum teres artery.
Intracapsular fracture neck of femur
Extracapsular fracture neck of femur
Hip joint dislocation
Fracture shaft of femur
Injuries Around Hip