How is the DHA test in radiology

Femoral neck fracture (= femoral neck fracture)

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The thigh bone consists of four parts: the knee joint, the shaft, the neck and the head, which together with the pelvic bone form the hip joint.

In the case of a femoral neck fracture, the bone is broken exactly at the transition from the femoral head to the shaft of the femur, and the affected leg can no longer bear the weight of the body. Therefore, a femoral neck fracture is unfortunately often very painful and severely restricts the affected person's ability to move.

A femoral neck fracture is a typical injury in old age, as the bone structure is weakened by osteoporosis (decalcification), especially in the area of ​​the femoral neck. Often, even small forces, such as a "banal" fall from standing height (e.g. stumbling over a carpet) or a sideways fall from a chair, are sufficient as the cause.

A femoral neck fracture is less common at a younger age, as it requires major trauma (e.g. traffic accident).

  • Pain in the hip and / or groin, possibly radiating to the leg and pelvis
  • Limitation of movement in the hip joint and inability to walk
  • Inability to lift the injured leg in a straight line
  • Bruising and swelling over the hip joint
  • Leg shortening and external rotation
  • Physical examination
  • X-ray of the pelvis and hip joint
  • Computed tomography (CT) only necessary in exceptional cases:
    • 1. to confirm the diagnosis with existing symptoms and x-rays without evidence of a fracture
    • 2. for the exact determination of the individual fracture elements (improves operative planning)

X-ray image of a
Femoral neck fracture, left

X-ray image of a
Femoral neck fracture, right

  • Computed tomography (CT) only necessary in exceptional cases:
    • to confirm the diagnosis with existing symptoms and x-rays without any indication of a fracture
    • for the exact determination of the individual fracture elements (improves operative planning)
  • Conservative:
    • Method of choice in the case of a stable, non-displaced fracture (= "compressed fracture")
    • Healing of the fracture by immobilizing the leg
    • Unfortunately, this case is the exception, as this fracture is often displaced and the head of the femur can be twisted in its direction.
  • Operative: the method of choice for displaced fractures

There are basically two methods available for surgical therapy:

  • On the one hand, an attempt can be made to correct the fracture, i. H. restore the correct anatomical position of the bone fragments (= open reduction) and hold them with screws. This procedure has the advantage that the body's own femoral head is retained, but it requires that it is still supplied with sufficient blood to ensure bone healing. This is why this procedure is also known as the “head-conserving procedure” (mean length of stay in hospital: 11.7 days).

X-ray after
Osteosynthesis with a
Dynamic femoral head screw (= DHS)

  • Unfortunately, due to the age of the patient, the blood flow to the head of the femur is often very poor or completely eliminated. In such cases, the stabilization with screws etc. would not hold, which is why a joint replacement (= endoprosthesis) is necessary (mean length of stay in hospital: 12.4 days).

X-ray after joint replacement
with a dual head prosthesis
(the blue arrow points to the
Replacement femoral head and
the purple arrow on the shaft
the prosthesis, which is in the
Thigh is built in)

Which method represents the optimal therapy for the patient therefore depends on the type of fracture and the regenerative capacity of the bone tissue. A decision is therefore always made individually.

Large studies in the recent past have shown that joint replacements often seem to be the better alternative for patients over 65 years of age.

  • rehabilitation
    • Mobilization as early as possible
    • regular instruction on movement exercises (muscle building, coordination training)
    • Gait training
    • in younger patients, pain-adapted partial exercise for 6 weeks
    • In older patients, pain-adapted full load is always used
  • Regular x-ray controls to check the position and the bone consolidation in the fracture gap (= bony consolidation)
  • Treatment of possible causes of falls or fall prophylaxis
  • Initiation of osteoporosis therapy
  • for osteosynthesis: removal of the implant after an individually determined time (depending on several factors, including the age of the patient, level of activity, local complaints), but no earlier than after 12 months
  • chronic pain
  • Arthrosis in the hip joint (= coxarthrosis)
  • Restriction of movement and reduced resilience of the hip joint
  • Axis, length or rotational malalignment / deformities (especially shortening and external rotation of the leg)
  • limping gait pattern
  • delayed tilting of the fracture, d. H. Shifting or twisting of the broken bone parts after the treatment attempt
  • Delayed or no healing of the fracture with the development of a "false joint" (= pseudarthrosis)
  • Loosening or rupture of the implant
  • Femoral head necrosis
  • Nerve damage (movement and / or sensory disorders)
  • Vascular injury (circulatory disorder)
  • Mobility and walking ability are not regained (rarely)

Authors: Ina Aschenbrenner, Prof. Dr. Peter Biberthaler (editorial team DGU website)