JOURNAL OF THE LOUISIANA STATE MEDICAL SOCIETY
An Elderly Man with a Swollen Knee, Significant Ecchymosis, and Minimal Knee Pain
David Aamodt, BA; Michael Serou, MD/PHD, and Harold Neitschman, MD
A 72-year-old man presents with left knee pain and swelling over several days. The pain and swelling started after he felt a “pop”when bending to pick up an object off the floor. His past medical history is significant for type 2 diabetes mellitus. Physical exam revealed significant ecchymosis on the anterolateral aspect of the thigh. There was a minimal amount pain upon knee flexion.
2
3
4
Figure 1. Lateral knee radiograph shows suprapattellar swelling.
Figure 2,3,4. Sagittal and axial PD MR images demonstrate tearing of quadriceps tendon and edema of vastus lateralis muscle with hematoma at musculotendinous junction.
1
DISCUSSION
deceleration. Muscle strains occur in the setting of overuse, inadequate stretching, and violent eccentric contraction. 3
A myotendinous strain occurs when there is excessive stretch on a muscle or tendon. Strains tend to occur in muscles that cross two joints, have a higher density of fast twitch muscle fibers, and undergo eccentric contraction. 1 Strains can be classified according to the amount fiber disruption associated with the muscle or tendon injury. A first degree strain results inmicroscopic disruption of less than 5%of fibers without gross anatomical distortion. Patients often present clinically with functional, but painful muscle contractions in the setting of mild pain and swelling. 2,3 A moderate, or second degree strain, results in a partial thickness macroscopic loss of fibers. However, the myotendinous unit remains intact and tendon fiber continuity remains. Clinical presentation will show moderate pain and swelling associated with weak and painful muscle contractions. Third degree strains result in complete disruption of the tendon unit with or without retraction. High grade strains are associated clinically with weak and painless muscle contractions. 2,3 The most commonly strained muscles of the lower extremity are the hamstrings, rectus femoris, and gastrocnemius muscles. 2 Strains represent 30% of sports related injuries and tend to occur in patients playing soccer, track and field, basketball, and football, as these sports require rapid acceleration and
Complete tendon tears occur in less than 1% of the population and usually begin in the 5th and 6th decade of life without gender predilection. 3 Full thickness tendon tears often occur as the end result of repetitive microtrauma or secondary to weakening by other chronic medical conditions such as gout, diabetes, hyperparathyroidism, and collagen vascular diseases. 4 Plain films of a quadriceps muscle strains will appear normal in 1st and 2nd degree strains, but may display an inferiorly displace patella in 3rd degree full thickness tears. Also, soft tissue swelling may be present. Short inversion time inversion-recovery (STIR) "Muscle strains occur in the setting of overuse, inadequate stretching, and violent eccentric contraction . "
J La State Med Soc VOL 169 JULY/AUGUST 2017 99
Made with FlippingBook Digital Publishing Software