Sinding-Larsen-Johansson (SLJ) Syndrome

Definition

SLJ syndrome is a traction apophysitis of the inferior pole of the patella, typically affecting adolescents during periods of rapid growth. It belongs to the family of osteochondroses and is considered a variant of jumper's knee.

Key Points

• Age of Occurrence: Typically 10-14 years
• Gender Predilection: More common in males
• Risk Factors: Sports involvement, especially jumping activities
• Associated Conditions: Part of the osteochondrosis family

Pathophysiology

• Repetitive mechanical stress on the developing patella
• Microtrauma at the insertion of the patellar tendon
• Inflammatory response leading to calcification
• Growth plate vulnerability during adolescent growth spurts

Clinical Features

Symptoms

• Anterior knee pain, especially during activity
• Pain worsens with jumping, running, and climbing stairs
• Pain on direct palpation of inferior pole of patella
• Symptoms typically bilateral in 20-30% of cases

Physical Examination

• Tenderness at inferior pole of patella
• Pain with resisted knee extension
• Swelling may be present
• Normal range of motion
• Pain with single-leg squat

Risk Assessment

• Sports requiring repetitive jumping
• Growth spurt periods
• Muscle imbalances
• Poor biomechanics

Diagnosis & Imaging

Radiographic Findings

• Fragmentation of inferior pole of patella
• Calcification within patellar tendon
• Soft tissue swelling
• Normal alignment of patella

Differential Diagnosis

• Osgood-Schlatter disease
• Patellar tendinopathy
• Patellofemoral syndrome
• Bipartite patella
• Patellar sleeve fracture

Additional Studies

• MRI: Usually not necessary but may show:
  • Bone marrow edema
  • Tendon thickening
  • Surrounding soft tissue inflammation
• Ultrasound: May help visualize tendon changes

Treatment & Management

Conservative Management

• Activity modification
• RICE protocol (Rest, Ice, Compression, Elevation)
• NSAIDs for pain management
• Physical therapy focusing on:
  • Quadriceps strengthening
  • Hamstring flexibility
  • Patellar mobility exercises
  • Core strengthening

Rehabilitation Protocol

• Phase 1: Pain Control (1-2 weeks)
  • Activity modification
  • Ice therapy
  • Gentle stretching
• Phase 2: Strengthening (2-6 weeks)
  • Progressive resistance exercises
  • Balance training
  • Proprioception exercises
• Phase 3: Return to Activity (6-12 weeks)
  • Sport-specific training
  • Gradual return to play
  • Biomechanical correction

Prognosis & Complications

Expected Outcomes

• Generally excellent with conservative treatment
• Resolution typically occurs with skeletal maturity
• Full return to sports in most cases
• Duration: 6-12 months average

Complications

• Chronic pain if untreated
• Recurrence with premature return to activity
• Potential for:
  • Patellar tendinopathy
  • Altered biomechanics
  • Decreased sports performance

Prevention Strategies

• Proper warm-up routines
• Regular stretching program
• Appropriate footwear
• Training load management