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Prepatellar Bursitis

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Other Names

  • Housemaid's knee
  • Carpenter's knee
  • Prepatellar Bursitis (PPB)
  • Infectious Prepatellar Bursitis
  • Noninfectious Prepatellar Bursitis
  • Aseptic Prepatellar Bursitis
  • Coal miner’s knee
  • Carpet layer’s knee[1]
  • Hemorrhagic bursitis


  • This page refers to bursitis of the pretallar bursa, most commonly referred to as prepatellar bursitis (PPB)


  • Described as early as 1961 among coal miners[2]


  • Overall underreported in literature with a paucity of studies[3]
  • Males > Females (need citation)
    • Majority of cases between 40 and 60 years of age
  • Pediatrics
    • More likely to be septic, in immunocompromised kids (need citation)


  • See: Bursopathies (Main)
  • General
    • Poorly described in the literature thus much of discussion, management is extrapolated from other bursopathies
    • Occurs due to friction between the dermal layers and patella, or compressive forces from direct trauma
  • Noninfectious/ Aseptic
    • Represents the majority of cases
    • Common etiologies include trauma, crystal deposition or systemic inflammatory diseases
  • Infectious
    • Between 20-30% are septic
    • Typically from skin lesions
    • Less commonly, can also arise spread primary cellulitis and in rare cases, from hematogenous
    • Common bacteria: Staphylococcus aureus (#1), Brucella sp.[4]
    • Uncommon pathogens: fungi, tuberculosis[5]
    • Up to 50% of all SB cases occur in immunocompromised patients (need citation)
    • #2 location for septic bursitis behind the olecranon, which is 4x more common[6]
  • Hemorrhagic
    • Can occur due to trauma or in patients on anticoagulation


  • Trauma
    • Most commonly due to chronic, repetitive microtrauma
    • Can be due to acute trauma
    • Typically aseptic unless violation of soft tissue
  • Crystal deposition
    • Including gout, psuedogout causing aseptic, inflammatory
  • Systemic inflammatory diseases
    • Includes rheumatoid arthritis, systemic lupus erythematosus, systemic sclerosis, or uremia[7]


Risk Factors

  • Sports
    • Wrestling[8]
    • Volleyball
    • Baseball and Softball catchers
  • Occupations
    • Common in occupations requiring kneeling
    • Housekeeping
    • Plumbing
    • Carpet installers
    • Gardening
    • Roofing
  • Autoimmune and Inflammatory

Differential Diagnosis

Clinical Features

  • History
    • Typically some sort of repetitive microtrauma
    • May be an acute trauma
    • Patients will endorse knee pain, anterior swelling
    • Trouble ambulating
  • Physical Exam
    • Obvious swelling of prepatellar bursa
    • Overlying erythema, warmth are often present
    • The prepatellar space will be tender with fluctuance, edema, crepitus
    • Range of motion is often restricted
    • Notably absent is a joint effusion
    • Septic vs aseptic can be difficult to distinguish clinically
  • Special Tests


Knee ultrasound demonstrating edema, cobblestoning and acute bursal fluid collection
Prepatellar Bursitis


  • Standard Radiographs Knee
    • Typically Normal
    • Used to exclude other pathology
  • Potential findings
    • Prepatellar soft tissue swelling
    • Calcifications in the prepatellar soft tissues in more chronic cases[9]


  • Findings
    • Hypoechoic fluid collection anterior to patella[10]
    • May have heterogenous debris
  • Also useful to guide aspiration or injection if indicated


  • Not typically indicated
  • Potential Findings
    • Low T1, bright T2/STIR signal intensity
    • Wall of bursa may be thickened, irregular


  • Labs are not typically indicated
  • However, if septic bursitis is a consideration, then labs are indicated
    • Aspiration: Fluid analysis, gram stain, culture, glucose, protein, lactate
    • Serum: CBC, ESR, CRP
Characteristics of bursal fluid in patients with septic and nonseptic prepatellar bursitis (courtesy of medscape)
Characteristic Appearance WBC (per µL) Differential count Bursal fluid–to–serum glucose ratio Gram stain Culture
Septic bursitis (SB) Purulent 1500-300,000; mean 75,000 Polymorphonuclear (PMN) cells < 50% Positive in 70% Positive
Nonseptic bursitis (NSB) Serosanguineous, straw colored, or bloody 50-10,000; usually < 3000 Predominantly mononuclear cells >50% Negative Negative


  • Not applicable



  • Most cases will completely resolve with prompt, appropriate treatment
    • No large scale studies evaluating prognosis of PPB


  • Indications
    • Inflammatory and non-infectious
  • Compression
  • Analgesics
  • Aspiration
    • Not typically recommended as first line therapy
    • Indicated if septic bursitis is a consideration
  • Corticosteroid Injection
    • Can be considered in refractory cases
    • No clear guidelines or evidence
  • Consider
    • Physical Therapy if recovery is slow or delayed
    • Occupational Therapy directed at activity modification
    • Knee Pads for occupations where repetitive microtrauma occurs due to kneeling
  • Septic Bursitis
    • Antibiotics with gram positive coverage
    • Orthopedic surgery consultation


  • Indications
    • Failure of conservative treatment
    • Septic bursitis
  • Technique
    • Open vs arthroscopic Bursectomy
    • Irrigation and debridement

Rehab and Return to Play


  • Needs to be updated

Return to Play

  • No clear guidelines
  • Can return to sport or occupation when symptoms and swelling have resolved
  • Should wear knee protection to prevent recurrence


  • Inability to return to sport
  • Septic Bursitis
    • Need for inpatient management
    • Need for surgery

See Also


  1. Myllymäki, T., et al. "Carpet-layer's knee: An ultrasonographic study." Acta Radiologica 34.5 (1993): 496-499.
  2. Sharrard, W. J. W. "Haemobursa in kneeling miners." (1961): 1103-1104.
  3. Baumbach SF , Lobo CM, Badyine I, Mutschler W, Kanz KG: Prepatellar and olecranon bursitis: literature review and development of a treatment algorithm. Arch Orthop Trauma Surg2014; 134(3): 359–70.
  4. Almajid, F. M. "A rare form of Brucella bursitis with negative serology: a case report and literature review." Case reports in infectious diseases 2017 (2017).
  5. MacLean, S., and S. Kulkarni. "Tuberculosis of the patella masquerading as prepatellar bursitis." The Annals of The Royal College of Surgeons of England 95.1 (2013): e17-e19.
  6. Ho G, Tice AD, Kaplan SR (1978) Septic bursitis in the prepatellar and olecranon bursae: an analysis of 25 cases. Ann Intern Med 89(1):21–27
  7. Diering, Nina, et al. "Calcific prepatellar bursitis in a patient with limited cutaneous systemic sclerosis." JDDG: Journal der Deutschen Dermatologischen Gesellschaft 15.12 (2017): 1248-1250.
  8. Mysnyk MC , Wroble RR, Foster DT, et al. : Prepatellar bursitis in wrestlers. Am J Sports Med1986; 14(1): 46–54.M.
  9. Stahnke M, Mangham DC, Davies AM. Calcific haemorrhagic bursitis anterior to the knee mimicking a soft tissue sarcoma: report of two cases. Skeletal Radiol. 2004 Jun;33(6):363-6. Epub 2004 May 1
  10. 2. Draghi F, Corti R, Urciuoli L, Alessandrino F, Rotondo A. Knee bursitis: a sonographic evaluation. (2015) Journal of ultrasound. 18 (3): 251-7. doi:10.1007/s40477-015-0168-z - Pubmed
Created by:
John Kiel on 10 June 2019 17:08:23
Last edited:
4 October 2022 15:52:41