Prepatellar Bursitis

Updated: Apr 17, 2017
  • Author: Kelly L Allen, MD; Chief Editor: Consuelo T Lorenzo, MD  more...
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Overview

Practice Essentials

The prepatellar bursa is a superficial bursa with a thin synovial lining located between the skin and the patella. Normally, it does not communicate with the joint space and contains a minimal amount of fluid; however, inflammation of the prepatellar bursa results in marked increase of fluid within its space.

Workup

Laboratory studies are not usually indicated to diagnose prepatellar bursitis. However, aspiration of prepatellar bursa fluid may be indicated because sepsis is common. Evaluate the aspirated fluid for white blood cell (WBC) count, protein, lactate, glucose, crystals, and Gram stain results.

Plain radiographs may show soft tissue swelling; however, radiographs are necessary only if other conditions are suggested (eg, fracture and/or dislocation).

Computed tomography (CT) scanning and magnetic resonance imaging (MRI) are reserved for cases that have been difficult to manage (eg, failure of initial treatment for septic prepatellar bursitis). [1, 2] Ultrasonography may be a useful technique for evaluating synovial fluid in the knee.

Management

Physical therapy

After the initial period of rest, the goal of physical therapy is to regain any loss of range of motion (ROM) while increasing the flexibility of the quadriceps and hamstrings. Use of therapeutic modalities can be helpful to assist stretching in this period.

Occupational therapy

The role of the occupational therapist in this scenario is to address modifications of activities in patients diagnosed with prepatellar bursitis secondary to overuse. Emphasize patient education, avoidance of kneeling, and use of kneepads if kneeling is necessary.

Surgical intervention

Incision and drainage of the prepatellar bursa usually is performed when symptoms of septic bursitis have not improved significantly within 36-48 hours. Surgical removal of the bursa (ie, bursectomy) may be necessary for chronic or recurrent prepatellar bursitis. [3] Arthroscopic or endoscopic excision of the bursa has been reported to have satisfactory results with less trauma than open excision. [4, 5]

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Pathophysiology

The prepatellar bursa is a flat round synovial-lined structure; its main function is to separate the patella from the patellar tendon and skin. This bursa is superficial, suggesting that it is undeveloped at birth. Within the first few months to years of life, the bursa arises from direct pressure and friction. The function of the bursa is to reduce friction and allow maximal range of motion (ROM).

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Epidemiology

Mortality/Morbidity

Mortality associated with prepatellar bursitis is rare. Morbidity usually is secondary to pain and limited function. [6] In the case of septic prepatellar bursitis, failure to diagnose in a timely manner may lead to increased morbidity secondary to infectious etiology.

Sex

Incidence of prepatellar bursitis is greater in males than females.

Age

Prepatellar bursitis can affect all age groups; however, in the pediatric age group, it is likely to be septic and to develop in an immunocompromised host.

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