Patella Fractures Clinical Presentation

Updated: Aug 23, 2022
  • Author: Alexandra K Schwartz, MD; Chief Editor: Thomas M DeBerardino, MD, FAAOS, FAOA  more...
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An individual who has sustained a patella fracture usually presents with pain in the affected knee. The history reveals a direct blow to the knee, a fall, or a combination of the two. Overlying abrasions, ecchymosis over the anterior aspect of the knee, or both may be present.


Physical Examination

Any lacerations must be assumed to communicate with the joint until this assumption is disproved by the saline load test. Because the retinaculum may have a large tear, it may be necessary to inject a significant amount of saline (up to 100 mL) to exclude an open joint. An accompanying intra-articular effusion may be present, which, if aspirated, will reveal fat globules. If the fracture is displaced, a defect is palpable at the fracture site.

The extensor mechanism must always be evaluated. As a result of the pain associated with the injury and hemarthrosis, the patient may be unable to perform a straight leg raise. Aspiration of the hemarthrosis under sterile conditions and the instillation of lidocaine may relieve the pain sufficiently to allow performance of a reliable examination. Disruption of the extensor mechanism renders the patient unable to extend the knee against gravity and usually implies that a tear is present in the medial and lateral quadriceps expansion.