Sinding-Larsen-Johansson (SLJ) syndrome is a painful knee condition that affects adolescents during periods of rapid growth. It is an "overuse" injury similar to Osgood-Schlatter, but the inflammation occurs at the bottom pole of the kneecap (patella) rather than on the shinbone. Constant pulling from the quadriceps tendon on the soft growth plate at the base of the patella causes irritation and, in some cases, small stress fractures or bone fragments.
SLJ is most common in active 10- to 14-year-olds involved in sports that require repetitive jumping or sprinting.
Point Tenderness: Specific pain at the very bottom of the kneecap.
Activity-Related Pain: Discomfort that worsens with running, jumping, climbing stairs, or kneeling.
Swelling: Mild puffiness or thickening around the lower part of the patella.
Limping: A noticeable change in gait after heavy physical activity or sports.
Muscle Tightness: Significant tension in the quadriceps muscles, which increases the "pull" on the kneecap.
Diagnosis is primarily clinical, focusing on the specific location of the tenderness.
Physical Examination
X-rays: Often used to rule out other fractures. In SLJ, the X-ray may show a small "spur" or a fragmented appearance at the bottom of the kneecap.
Like most growth-related conditions, SLJ is self-limiting and typically resolves once the growth plate matures and hardens into solid bone.
Rest and Modification: Reducing high-impact "jumping" sports during painful flare-ups.
Ice: Applying ice to the bottom of the kneecap for 15 minutes after activity to calm inflammation.
Quadriceps Stretching: Gently improving the flexibility of the front thigh muscles to reduce the mechanical tension on the patella.
Eccentric Strengthening: Low-impact exercises (like slow step-downs) to help the tendon handle loads more effectively.
Knee Sleeves: A neoprene sleeve can provide compression and warmth, which often helps manage the dull ache during daily movement.
NSAIDs: Short-term use of anti-inflammatories to manage pain during acute phases.
The "cure" for Sinding-Larsen-Johansson is time and growth. Once the growth plate at the base of the kneecap closes, the symptoms typically disappear.