Types of Hip Fractures
What is the anatomy of the hip joint?
It is a ball and socket joint between the socket in the pelvis called acetabulum and the head of the femur bone.
It is covered from all around by a thick fibrous tissue called capsule which increases the stability of the joint. The blood supply is from the medial and lateral branches of the profunda femoris artery.
The femoral nerve runs in front of the hip joint and the sciatic nerve behind it.
What is a hip fracture?
A hip fracture is a commonly encountered fracture usually seen in the elderly as a result of direct fall onto the hip. This is usually complicated by a number of coexisting medical problems. Treatment depends on the type of fracture, age, general health and mobility levels of the patient. Hip fractures are broadly divided into two categories.
1. Intra-capsular Hip Fracture: fracture sustained within the capsular attachment of the hip. This is prone to develop avascular necrosis (avascular necrosis refers to death of previously healthy bone) as the there is high chance for the blood supply to the head of femur to get compromised.
Intra-capsular fractures are of two types.
a.) Undisplaced: There is minimal or no displacement between the broken bit and the main bone.)
b.) Displaced: There is significant displacement between the fractured bone and the main bone.
2. Extra-capsular Hip Fracture: fracture sustained outside the capsular attachment of the hip.
There are four types of extra-capsular fractures.
a.) Basi-cervical fractures: They are seen at the base of the femoral neck. Because of their border line position they are considered with extra-capsular fractures.
b.) Inter-Trochanteric fractures: The fracture line runs through the area between the greater and the lesser trochanter. They are usually seen in the older age group. The current treatment of choice is a Dynamic Hip Screw (DHS).
c.) Greater Trochanter fractures: Greater trochanter fractures are rare in isolation. Treatment is usually non operative except in young patients where they are better fixed.
d.) Lesser Trochanter fractures: They are rare and can be often pathological or in young patients can be due to avulsion effect of the strong pull of the tendons attached to it.
There are many ways of surgically fixing hip fractures depending on the classification mentioned above.
What are the symptoms of hip fractures?
The patient may complain of pain in the hip or the groin after a fall or trauma.
There may be tenderness and painful, restricted hip movements in an undisplaced fracture or a shortened, externally rotated leg if the fracture is displaced.
Lifting leg straight up into the air is painful and usually impossible. There may be bruising or abrasions around the hip.
What are the investigations for a hip fracture?
Usually two views of the hip joint, one from the front to back and the other from the side are enough to diagnose it. In doubtful cases an MRI or CT scan may be helpful. If a patient persistently complains of pain in the hip with normal initial x-rays then repeat x-rays may be needed after a few days to rule out an impacted fracture which may have been missed initially.
What is the treatment for hip fractures?
Treatment depends on the type of fracture, age, general health and mobility levels of the patient.
* Undisplaced intra-capsular hip fractures: Here the choice of treatment does not depend on the age of the patient.
* Internal fixation using three cannulated screws or pins is the treatment of choice. Better results are obtained with surgery.Some surgeons also use a Dynamic Hip Screw instead of cannulated screws, for reasons of increased rotational stability.
* Non operative treatment is used if the patient presents late with evidence that the fracture is uniting.
* Displaced intra-capsular fractures:
* Patients less than 65 years of age are classified as young. In them internal fixation using pins or screws (Dynamic Hip Screw) is the preferred treatment as they are more likely to recover from the fracture and have a lower risk of developing avascular necrosis.
* Younger patients require follow up to see if they develop avascular necrosis of the femoral head.
Patients over 65 years can be treated with:
1. Unipolar Hemi-Arthroplasty: The prosthesis has a metallic head that articulates with the acetabulum (socket in the pelvis) directly. The whole prosthesis is a single unit. It is mainly used for pain relief. Patient group most likely to benefit is the severely elderly who is home bound, demented, has multiple medical problems and doesn’t mobilize much independently except bed to chair transfers.
2. Bipolar Hemi Arthroplasty: The prosthesis has a larger head on top of a smaller head. The small head sits on the prosthesis while the larger head articulates with the acetabulum. This arrangement improves function and gives a better range of movement. It is used for elderly patients who are reasonably ambulant and manage their daily activities of life independently.
3. Total Hip Replacement: In this procedure both the parts of the hip joint namely the upper part of femur and the acetabulum are replaced. This has the best functional outcomes of the three procedures and restores mobility to almost normal levels. It is recommended for patients who are fit and active.
What are the Complications of hip fracture?
1. Avascular Necrosis: It refers to the condition when a part of the bone dies as its blood supply gets compromised due to variety of factors. It can occur after hip fractures. It presents with a persistently painful hip in absence of trauma or infection. An MRI is needed to confirm it.
2. Infection: If infection happens after metalwork has been fixed in the hip joint then it may lead to septic arthritis. Treatment lies in long term intravenous antibiotics or removal of metalwork if no significant progress is made even after a few weeks. A second operation may be needed to remove the infected tissues and wash the joint again to get rid of the bugs.
3. Non union: Non union or failure of fixation can be treated by Arthroplasty.
4. Re-fracture: A further fall can cause re-fracture at the same site or near by. It can be seen at the tip of the plate or screw or plate.
5. Death: A hip fracture increases the chances of death within the first one to one and a half years after the event after which the chances go back to what is expected for that age. This is due to generally reduced mobility levels and increasing co-morbidities.