# Lower Limb Osteochondrosis and Apopbysitis in Young Athletes--A Comprehensive Review
## 4 Sinding-Larsen-Johansson Syndrome: Presentation, Diagnosis, and Management  
Sinding-Larsen-Johansson syndrome (SLJS) is a disorder marked by traction apophystis at the inferior pole of the patella [50]. It primarily affects adolescents during growth spurts, with the highest incidence observed in individuals aged 10 to 13 years [51]. The etiology of SLJS is attributed to repetitive mechanical stress on the developing skeletal structure at the patellar tendon insertion site, leading to the detachment of the ossification center at the patellar apex [52]. The apex of the patella is located at the inferior pole of the patella and is connected to the tibial tuberosity by the patellar ligament. Figure 2 shows a case of SLJS in an active adolescent. The images show an irregular contour of the patella apex and fragmentation of the ossification nucleus in this area.  
SLJS, similar to OSD, is classified as an overuse injury [53]. Affected young athletes typically report localized pain in the anterior compartment of the knee joint, which is exacerbated during activities such as jumping or running and is often accompanied by soft tissue swelling [54]. Patients often present with tightness of the surrounding musculature, including the quadriceps, hamstrings, and gastrocnemius, which contributes to increased  
Figure 2: Sinding–Larsen–Johansson syndrome on the ultrasound image. (**a**,**b**) Irregular contour of the patellar apex.  
stiffness in the knee joint [55]. Physical examination typically reveals tenderness at the junction of the patella and patellar tendon, as well as local signs of inflammation that may impair knee function [56]. The pain worsens with flexion in conjunction with weight bearing on the knee joint [57]. In addition, appropriate imaging modalities such as standard radiography, ultrasound, and MRI should be added to the patient's assessment [58]. These imaging techniques may reveal calcifications and ossifications at the interface between the patella and patellar tendon in addition to cartilage edema and fragmentation at the inferior pole of the patella [59].  
Therapeutic management of SLJS primarily relies on conservative treatment strategies, which emphasize patient education and the modification of current physical activity regimens [60; 61]. Physical activity must remain an integral part of the daily routine of young athletes. However, the intensity and duration should be adapted to individual tolerance limits. The inclusion of strengthening and isometric exercises for the lower limbs is crucial to prevent muscle atrophy [59]. Additionally, flexibility training, particularly for the hamstrings, is of paramount importance, as reduced mobility of this muscle group is often observed in affected athletes. Complementary measures, such as passive mobilization of the lower limbs and swimming (e.g., crawl and backstroke), can improve the overall rehabilitation program [61]. For acute pain episodes, local ice massage has been shown to be an effective analgesic measure, often supplemented by short-term administration of non-steroidal anti-inflammatory drugs (NSAIDs) to relieve discomfort [62]. This comprehensive approach aims to improve the athlete's functional capacity while minimizing pain and promoting recovery [62]. If conservative treatment does not produce satisfactory results, surgery may be required, in which the SLJS is removed arthroscopically [63]. In such cases, the surgical procedure entails the removal of necrotic intratendinous tissue through surgical debridement. This approach should be regarded as a last resort for patients who are particularly unresponsive to conservative treatment. A surgical approach to the treatment of SLJS is supported by evidence drawn from the relevant literature. In a case report, [PERSON] et al. [63] described the removal of SLJS via arthroscopic surgery. The surgical procedure resulted in the complete resolution of symptoms, enabling the patient to resume competitive sports within five months.