Patellar fracture are a violation of the integrity of the patella as a result of traumatic exposure. The pathology is accompanied by swelling of the knee and pain, which increases when bending the leg in the knee joint, restriction of extension of the lower leg. With injuries with displacement, walking becomes impossible. Diagnosis includes X-ray examination, if necessary, MRI and puncture of the knee joint. Patellar fractures without displacement are treated by fixing with a plaster splint, if there is a displacement, surgery is required.
S82.0 Patellar fracture
Patellar fractures account for 1.5% of the total number of fractures. They are more common in middle-aged and elderly people, and are usually the result of street trauma. They are often accompanied by a pronounced displacement of fragments caused by traction of the quadriceps femoral muscle. They are characterized by a fairly favorable prognosis. Pathology is treated by traumatologists.
Usually, a fracture of the patella is the result of a direct injury when falling on a bent knee or hitting the kneecap on a sharp and hard object. A fracture as a result of an indirect injury is possible with a sudden sharp contraction of the quadriceps femoris. There is a mixed fracture mechanism that occurs when the elements of direct and indirect trauma are combined. A fracture of the patella is often combined with damage to the lateral flexor apparatus – tendon fibers of the quadriceps femoris. When the tendons are torn, there is a pronounced divergence of patellar fragments.
The patella is a flat rounded bone located on the anterior surface of the knee joint. The tendons of all the heads of the quadriceps femoris are attached to the upper part of the patella (patella), and the patella’s own ligament is attached to the lower part. From the outside and inside, the bone is supported by lateral ligaments.
With its smooth inner surface, the kneecap is adjacent to the patellar surface of the femur. The rough outer surface of the patella is covered with tendon fibers. The patella protects the knee in case of injuries and performs the function of a block that increases the strength of the quadriceps femoral muscle.
There are closed and open (communicating with the external environment through the wound) fractures of the patella. Depending on the localization, specialists in the field of traumatology and orthopedics divide patellar fractures into longitudinal, transverse, comminuted, marginal. Most often, transverse fractures of the kneecap are observed, less often – marginal, very rarely – longitudinal. All fractures of the patella, with the exception of marginal fractures of the apex, are intraarticular.
There is a pronounced swelling in the area of the knee joint. When feeling, sharp soreness, a gap between the fragments, hemarthrosis (blood in the knee joint) is revealed. Sometimes pathological mobility and crunch (crepitation) of bone fragments are determined. The pain increases sharply when trying to bend the knee. Active extension of the lower leg is impossible or severely limited. With a fracture without displacement, the patient retains the ability to walk, but walking is accompanied by severe pain. A fracture of the patella with displacement excludes walking, lifting the straightened limb and active movements in the joint.
The diagnosis of a patellar fracture is established during a consultation with a traumatologist on the basis of a characteristic clinical picture and X-ray examination data. Additionally, an MRI of the knee joint is performed. Hemarthrosis is confirmed by a diagnostic puncture of the joint. A patellar fracture is differentiated from a rupture of the patellar ligament of its own, a rupture of the quadriceps tendon, traumatic arthritis and prepatellar bursitis. In all these cases, there is no gap between the fragments, balloting of the kneecap is detected, the patella is completely displaced.
In some cases, a fracture of the patella has to be differentiated with an anomaly of the patella development – a divided patella (patella partita). Unlike patella partita patella fracture, there is no trauma in the anamnesis, there are no sharp pains, the gap between the bone fragments is smooth, rounded. Patella partita, as a rule, is detected from two sides.
In case of damage without displacement or with a displacement of no more than 0.5 cm, conservative treatment is indicated – fixation of the limb with a posterior plaster splint for a period of 2-3 weeks. The patient is allowed to walk on crutches. After removing the splint, physical therapy, massage and physiotherapy are prescribed: UHF, electrophoresis, magnetolaser therapy, etc. The ability to work is restored after 1.5-2 months.
A fracture of the patella with a displacement of fragments by more than 0.5 cm is an indication for surgery. Various techniques can be applied using soft tissue suture, bone suture and muscle-tendon plasty. The most popular method is the Berger–Schultze operation (convergence of fragments with subsequent stitching of soft tissues around the patella). The period of immobilization in the postoperative period is 1 month. After removing the plaster splint, massage, physiotherapy and therapeutic gymnastics are prescribed.
With multi–splintered fractures in some cases (the presence of small fragments, the inability to restore the patella), excision operations are used – removal of bone fragments or the entire patella. If it is possible to save the kneecap, excision operations are not recommended.
Prognosis and prevention
The prognosis is usually favorable, the limb functions are fully restored. The duration of disability depends on the severity of the injury and ranges from 2 months for uncomplicated patellar fractures to 3 months for fractures with damage to the quadriceps tendon. Prevention provides for measures to prevent street injuries, especially in the winter season.