Hip Fractures: Types & Management // Fractures of Hip

A comprehensive guide to hip fractures, including classification, causes, surgical and non-surgical management.

1. FRACTURES OF HIP PREPARED BY SOMA BALAJI PT MSK & SPORTS

2. ANATOMY The hip joint consists of an articulation between the head of femur  and  acetabulum  of the pelvis. The acetabulum is a cup-like depression located on the inferolateral aspect of the pelvis. Its cavity is deepened by the presence of a fibrocartilaginous collar – the  acetabular labrum . The head of femur is hemispherical, and fits completely into the concavity of the acetabulum.

3. MUSCULATURE The movements that can be carried out at the hip joint are listed below, along with the principle muscles responsible for each action: Flexion  – iliopsoas, rectus femoris, sartorius, pectineus Extension  – gluteus maximus; semimembranosus, semitendinosus and biceps femoris (the hamstrings) Abduction  –  gluteus medius , gluteus minimus , piriformis and tensor fascia latae Adduction  – adductors longus, brevis and magnus, pectineus and gracilis Lateral rotation  – biceps femoris, gluteus maximus, piriformis, assisted by the obturators, gemilli and quadratus femoris. Medial rotation  – anterior fibres of gluteus medius and minimus , tensor fascia latae

4. DISLOCATIONS OF THE HIP There are three main types of dislocations of the hip: Posterior dislocation (the commonest); Anterior dislocation; Central fracturedislocation . All of these may be associated with fracture of the lip of the acetabulum. POSTERIOR DISLOCATION OF THE HIP The head of the femur is pushed out of the acetabulum posteriorly. In about 50 per cent of cases, this is associated with a chip fracture of the posterior lip of the acetabulum, in which case it is called a fracture-dislocation.

5. MECHANISM OF INJURY The injury is sustained by violence directed along the shaft of the femur, with the hip flexed. It requires a moderately severe force to dislocate a hip, as often occurs in motor accidents. The occupant of the car is thrown forwards and his knee strikes against the dashboard. The force is transmitted up the femoral shaft, resulting in posterior dislocation of the hip. It is, therefore, also known as dashboard injury.

6. Radiological features: The femoral head is out of the acetabulum. The thigh is internally rotated so that the lesser trochanter is not seen. Shenton’s line is broken. One must look for any bony chip from the posterior lip of the acetabulum or from the head. A comparison from the opposite, normal side may be useful. SHENTON’S LINE

7. TREATMENT Reduction of a dislocated hip is an emergency, since longer the head remains out, more the chances of it becoming avascular. In most cases it is possible to reduce the hip by manipulation under general anaesthesia . The chip fracture of the acetabulum, if present, usually falls in place as the head is reduced. Technique of closed reduction: The patient is anaesthetised and placed supine on the floor. An assistant grasps the pelvis firmly. The surgeon flexes the hip and knee at a right angle and exerts an axial pull. Usually one hears a ‘sound’ ofreduction , after which it becomes possible to move the hip freely in all directions. The leg is kept in light traction with the hip abducted, for 3 weeks. After this, hip mobilisation exercises are initiated.

8. Open reduction may be required in cases where: Closed reduction fails, usually in those presenting late; If there is intra-articular loose fragment not allowing accurate reduction; and If the acetabular fragment is large and is from the weight bearing part of the acetabulum. Such a fragment makes the hip unstable.

9. ANTERIOR DISLOCATION OF THE HIP This is a rare injury, usually sustained when the legs are forcibly abducted and externally rotated. This may occur in a fall from a tree when the foot gets stuck and the hip abducts excessively, or in a road accident. Clinically, the limb is in an attitude of external rotation. There may be true lengthening, with the head palpable in the groin. Treatment and complications are similar to that of posterior dislocation.

10. CENTRAL FRACTURE-DISLOCATION OF THE HIP In this common injury, the femoral head is driven through the medial wall of the acetabulum towards the pelvic cavity. The displacement of the head varies from the minimal to as much as the whole head lying inside the pelvis. Joint stiffness and osteoarthritis are inevitable. If the fragments fall in place and reasonably reconstitute the articular margins, the traction is continued for 8-12 weeks. In some young individuals, in whom the fragments do not fall back in place by traction, surgical reconstruction of the acetabular floor may be necessary.

11. FRACTURE OF NECK OF THE FEMUR There are two types of fractures of neck of the femur: intra-capsular and extra-capsular. As a matter of convention, the term ‘fracture of the neck of the femur’ is used for intra-capsular fracture of the neck. The extra-capsular fracture is usually called inter-trochanteric fracture. PATHOANATOMY Most of these fractures are displaced, with the distal fragment externally rotated and proximally migrated. These displacements also occur in inter-trochanteric fracture in which these are more marked.

12. CLASSIFICATION Fractures of the neck of the femur can be classified on different basis as discussed below: Anatomical classification : On the basis of anatomical location of the fracture, it can be classified as: Subcapital – a fracture just below the head; Transcervical – a fracture in the middle of the neck; or Basal – a fracture at the base of the neck.

13. PAUWEL’S CLASSIOFICATION This classification is based on the angle of inclination of the fracture in relation to the horizontal plane. The fractures are divided into three types (type 1-3). The more the angle, the more unstable is the fracture, and worse the prognosis.

14. GARDENS CLASSIFICATION

15. MECHANISM OF INJURY In elderly people, the fracture occurs with a seemingly trivial fall. Osteoporosis is considered an important contributory factor at this age. Clinical features: Occasionally, a patient with an impacted fracture may arrive walking; the only complaint being a little pain in the groin. There is little pain or swelling. The fracture diagnosis is missed for days or weeks. Careful examinations reveals the following: External rotation of the leg, the patella facing outwards. Shortening of the leg, usually slight. Tenderness in the groin. Attempted hip movements painful, and associated with severe spasm. Active straight leg raising not possible.

16. Radiological features The following features should be noted. Break in the medial cortex of the neck. External rotation of the femur is evident; the lesser trochanter appearing more prominent. Overriding of greater trochanter, so that it lies at the level of the head of the femur. Break in the trabecular stream. Break in Shenton’s line. In impacted fracture, the only radiological finding is bending of the trabeculae. There is no clear cut fracture line. Comparison with the opposite hip may be useful.

17. Treatment

18. In some younger patients presenting late, to achieve closed reduction of the fracture may be difficult. In such cases, an open reduction of the fracture is done. Internal fixation: Any of the following implants may be used for internal fixation: Multiple cancellous screws – most commonly used. Dynamic hip screw (DHS) – used sometimes. Multiple Knowle’s pins/Moore’s pins used in children.

19. McMurray’s osteotomy This is an oblique osteotomy at the inter-trochanteric region. The direction of osteotomy is medially upwards, beginning at the base of the greater trochanter and ending just above the lesser trochanter. Once the osteotomy is made, the distal fragment is displaced medially and is abducted. The position is held by an external support (hip spica) or by internal fixation with plate and screws. The osteotomy converts the shearing stresses at the fracture site into compressive forces, thus enhancing fracture union.

20. Hemiarthroplasty This is a procedure used for elderly patients. In this, the head of the femur is excised and replaced by a prosthesis. There are two types of prosthesis commonly in use: unipolar and bipolar. UNIPOLAR Unipolar prosthesis have a 'head' with an attached stem. The stem is introduced inside the medullary canal of the femur, and the head sits over the neck of the femur. BIPOLAR In bipolar prosthesis, the head has two parts: a smaller head, and a mobile plastic cup on top of it. Hence, when the prosthesis is fitted on the neck, there is movement at two planes – one between the acetabulum and the plastic cup, and other between the plastic cup and the head.

21. M EYER’S PROCEDURE In this procedure, the fracture is reduced by exposing it from behind. It is fixed with multiple screws and supplemented with a vascularised muscle-pedicle bone graft taken from the femoral attachment of the quadratus femoris muscle. It is also used for non-union of the femoral neck fractures.

22. PAUWEL’S OSTEOTOMY This is a valgus ostestomy at the level of the lesser trochanter. A valgus effect so created at the fracture site results in converting the shearing forces at the fracture site into compression forces. The osteotomy is fixed with double-angle blade plate. It is a technically demanding operation.

23. Neck reconstruction The fracture is exposed from behind, the ends freshened and the fracture stabilized with multiple screws and muscle-pedicle graft ( Baksi's procedure). Some surgeons use free fibular graft for reconstructing the neck.

24. Treatment of cases presenting late Patient with fracture of the neck of the femur often present late, either because the fracture is not diagnosed in time or the facilities for treatment were not available. These present a difficult problem because after 2-3 weeks, closed reduction is not possible, and opening the fracture is associated with complications such as avascular necrosis. COMPLICATIONS Non-union Avascular necrosis Osteoarthritis

25. INTER-TROCHANTERIC FRACTURES Fractures in the inter trochanteric region of the proximal femur, involving either the greater or the lesser trochanter or both, are grouped in this category. In the elderly, the fracture is normally sustained by a sideway fall or a blow over the greater trochanter. PATHOANATOMY The distal fragment rides up so that the femoral neck-shaft angle is reduced (coxa vara ). The fracture is generally comminuted and displaced. Very rarely, it can be an undisplaced fracture.

26. DIAGNOSIS Pain in the region of the groin and an inability to move the leg. Swelling in the region of the hip, and the leg will be short and externally rotated. Tenderness over the greater trochanter. Radiological features Presence of comminution of the medial cortex of the neck, avulsion of the lesser trochanter and extension of the fracture to the subtro-chanteric region indicate an unstable fracture, and a poor prognosis.

27. TREATMENT The main objective of treatment is to maintain a normal femoral neck-shaft angle during the process of union. This can be done by conservative means (traction) or by internal fixation. Conservative methods: There are a number of tractions described for an inter-trochanteric fracture. Those used most frequently are Russell’s traction and skeletal traction in a Thomas splint.

28. Operative methods: The fracture is reduced under X-ray control and fixed with internal fixation devices. The most commonly used ones are: Dynamic Hip Screw (DHS); Ender’s nails and Nails such as gamma nail, Proximal femoral nail (PFN). External fixation is useful for patients with bed sores, and for those who are unfit for a major operation.

29. COMPLICATIONS Malunion Osteoarthritis