Management of Sinding-Larsen-Johansson Syndrome
Conservative treatment with activity modification is the primary management approach for Sinding-Larsen-Johansson (SLJ) syndrome, with most patients achieving complete resolution within 2-8 months. 1
Clinical Presentation and Diagnosis
SLJ syndrome typically affects physically active adolescents aged 9-17 years, with a male predominance, presenting as localized anterior knee pain at the inferior pole of the patella. 1 The pain characteristically worsens with patellar loading during knee flexion and is accompanied by subpatellar swelling and functional limitation. 2
Ultrasound is the preferred initial imaging modality for confirming the diagnosis, showing characteristic lesions at the inferior patellar pole. 1, 2 MRI provides additional diagnostic value when ultrasound findings are equivocal or when differentiating from patellar sleeve avulsion fractures is necessary. 1, 3
Conservative Treatment Protocol
The cornerstone of management includes the following components:
Activity Modification
- Immediate cessation of sports activity and activities that load the patella during flexion 1, 2
- Rest period typically lasting 2-8 months depending on symptom severity 1
Adjunctive Therapies
- Cryotherapy for pain and inflammation control 1
- NSAIDs for symptomatic relief 1
- Passive mobilization to maintain range of motion 1
- Muscle restraint techniques and isometric exercises once acute symptoms subside 1
Monitoring
- Ultrasound follow-up to document resolution of pathologic findings 2
- Clinical reassessment at regular intervals to guide return to activity
Important Clinical Pitfalls
Critical: Distinguish SLJ syndrome from patellar sleeve avulsion fractures, as the latter typically requires surgical management. 3, 4 Overlap between these conditions can occur, and a minimally displaced acute patellar sleeve avulsion may present in a patient with pre-existing SLJ syndrome. 3, 4 High clinical suspicion based on mechanism of injury (particularly acute trauma during jumping), severe pain with complete loss of function, and inability to perform straight leg raise should prompt MRI evaluation to rule out avulsion fracture. 4
Refractory Cases
For the rare patient who fails conservative management after 4-6 months and cannot return to competitive sports, arthroscopic excision of the SLJ lesion may be considered. 5 In a professional athlete, this approach led to complete symptom resolution and return to competitive sports within 5 months. 5
Expected Outcomes
With appropriate conservative management, complete recovery with resolution of symptoms and ultrasound abnormalities occurs within 5 months in most cases. 2 The prognosis is excellent when activity modification is strictly adhered to during the acute phase. 1, 2