Patellar/Quadriceps Tendon Rupture



Ovid: 5-Minute Sports Medicine Consult, The


Patellar/Quadriceps Tendon Rupture
Warren Bodine
Jeffrey W. R. Dassel
Basics
Description
  • Partial or complete rupture of the patellar or quadriceps tendon
  • Synonym(s): Extensor mechanism disruption
Epidemiology
  • In the general population, quadriceps and patellar tendon ruptures are the 2nd and 3rd most common cause of extensor mechanism disruption, respectively (following patellar fracture). Both have increased in prevalence in recent decades but remain rare.
  • True incidence and prevalence not known, but in a higher-risk active-duty military population, the incidences of patellar and quadriceps tendon ruptures were 13 and 4 per 100,000, respectively (1).
  • Patellar tendon ruptures are more common in athletes and individuals <40 yrs of age.
  • Complete quadriceps tendon ruptures are more common in those >40 yrs of age.
  • Ruptures most commonly occur unilaterally; systemic disease increases the risk of bilateral ruptures.
  • Ethnicity may influence incidence and prevalence, with blacks and Hispanics more predisposed to tendon ruptures than whites (1).
Risk Factors
  • Trauma
  • History of patellar/quadriceps tendinosis or patellar spurs
  • High-power sports (eg, high jump, basketball, weight lifting)
  • Steroid injection in the patellar or quadriceps tendon
  • Fluoroquinolone use in previous 6 mos
  • Systemic lupus erythematosus
  • Rheumatoid arthritis
  • Diabetes mellitus
  • Hyperparathyroidism
  • Chronic kidney disease
  • Uremia
  • Obesity
  • Gout
  • Previous total-knee arthroplasty, ACL reconstruction using patellar autograft or excision of tendinosis
Etiology
  • Most commonly due to eccentric overload of myotendinous unit with foot planted and knee partially flexed, as occurs in landing from a jump or fall.
  • Patellar tendon ruptures usually are complete, occurring most commonly at the osseotendinous junction in athletic trauma versus midsubstance in those with systemic disease (2).
  • Quadriceps tendon ruptures usually occur distally, through pathologic tissue 0–2 cm from the superior patellar pole. Pathologic changes are most commonly degenerative in nature (2).
  • Chronic tendinosis, corticosteroids, fluoroquinolones, and systemic disease change tendon structure, decreasing its failure point.
Commonly Associated Conditions
  • Jumper's knee/tendinopathy
  • Patellar spurs
  • Quadriceps injury
Diagnosis
History
  • Mechanism of injury: Specifically jumping, stumbling, or slipping
  • Hearing or feeling “pop” or tearing sensation
  • Immediate, disabling pain
  • Difficulty straightening or bearing weight on affected extremity
  • Acute onset of swelling
  • History of chronic patellar or quadriceps tendinosis
  • History of steroid injection in tendon
  • Recent fluoroquinolone use
Physical Exam
  • Diffuse swelling or effusion
  • Ecchymosis, possible hemarthrosis
  • Patella alta in complete patellar tendon rupture
  • Patella baja in complete quadriceps tendon rupture
  • Palpable defect (may be masked by swelling acutely or by scar tissue in delayed evaluation)
  • Tenderness to palpation over patellar poles, retinaculum, or tibial tuberosity
  • Pain with knee flexion
  • Inability to actively achieve full extension/having significant extension lag
  • Absence of/altered patellar tendon reflex
  • Altered gait if able to bear weight
  • Quadriceps atrophy (in chronic cases)
Diagnostic Tests & Interpretation
Lab
Laboratory studies are rarely indicated but, depending on history and physical exam, may be performed to evaluate for associated risk factors.
Imaging
  • Plain radiographs:
    • Diagnosis usually based solely on history, physical exam, and plain radiographs.
    • Obtain anteroposterior, lateral, tunnel, and patellar (sunrise or Merchant) views.
    • Contralateral films allow comparison of patellar height.
    • Superior or inferior patellar migration without fracture is conclusive for rupture.
    • Avulsion fractures may occur at the superior or inferior patellar poles or the tibial tuberosity.
  • US:
    • More commonly performed in Europe than U.S.
    • High-resolution US shows hypoechogenicity in acute tears, tendon thickening, and heterogeneous echotexture in chronic tears.
  • MRI:
    • May be performed if diagnosis cannot be made by clinical and radiographic examination
    • Findings include tendon fiber disruption with associated edema or hemorrhage.

P.447


Pathological Findings
Pathologic changes usually are degenerative, including hypoxic degenerative tendinopathy, mucoid degeneration, tendolipomatosis, and calcifying tendinopathy (2)[B].
Differential Diagnosis
  • Fracture
  • Muscular strain (grade I or II)
  • Patellar subluxation/dislocation
  • Meniscal or ligamentous pathologies
  • Osgood-Schlatter disease
  • Sinding-Larsen-Johansson syndrome
Ongoing Care
Patient Education
  • Reasonable function can be obtained in most individuals, especially in the acute tendon rupture that is repaired immediately.
  • Most patients can return to their previous occupation, but many have difficulty returning to their preinjury athletic level, particularly with quadriceps tendon ruptures.
Prognosis
  • Outcome after repair is closely related to the length of time between injury and repair, the quality of the preexisting tissues, and the tendon healing at the proper length and tension.
  • If the tendon is repaired immediately, most patients experience nearly full return of knee motion.
Codes
ICD9
  • 727.65 Nontraumatic rupture of quadriceps tendon
  • 727.66 Nontraumatic rupture of patellar tendon


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