Abstract
Background:
Apophysitis of the knee is common in adolescent patients aged 10-15 with a prevalence of 11% in males and 8% in females. Osgood-Schlatter Disease (OSD) and Sinding-Larsen-Johansson Syndrome (SLJS) are types of apophysitis at the tibial tubercle and inferior pole of the patella, respectively. Tibial tubercle avulsion fractures (TTAF) and inferior pole patellar sleeve avulsion fractures (IPPSAF) share anatomic location with OSD and SLJS, respectively. It has been suggested that OSD is a risk factor for TTAF and that SLJS is a risk factor for IPPSAF, but clinical data describing patients with both apophysitis and the corresponding avulsion fracture is sparse.
Objectives:
We aim to present clinical data regarding biometrics and sport exposure for patients with apophysitis and avulsion fracture at both locations. We hypothesize that patients with one type of apophysitis are more likely to present with avulsion fracture at the corresponding end of the patellar tendon. We hypothesize that increased number of sports among patients with apophysitis will be associated with the corresponding avulsion fracture and that the presence of apophysitis will be associated with fractures requiring surgical management.
Methods:
We queried the electronic health record (EHR) for patients aged 18 years or younger seen by Orthopedics at Children’s Hospital of Philadelphia and received ICD-10 Codes for OSD, SLJS, TTAF or IPPSAF between 2017 and March 2024. Age, sex, height, BMI, flexibility and range of motion measurements, number of sports played, and surgical management were manually extracted from the EHR by trained reviewers.
Results:
Of the 1530 patients in our cohort diagnosed with OSD, 35 went on to sustain a TTAF (2.3%). Of the 778 patients in our cohort diagnosed with SLJS, 21 went on to sustain an IPPSAF (2.7%). Logistic regression analysis showed TTAF was significantly associated with OSD diagnosis (OR=5.71, p<0.001), and IPPSAF was significantly associated with SLJS diagnosis (OR=14.75, p<0.001). OSD does not increase the risk of avulsion fracture requiring surgery (OR=0.35, p=0.007). Patients present with OSD at a mean age of 12.7 years, compared to 11.1 years for SLJS. Higher BMI increases the odds of OSD (OR=1.11, p<0.001) and decreases the odds of SLJS (OR=0.86, p<0.001).
Conclusion:
We describe a large clinical cohort of patients with apophysitis and avulsion fractures at both ends of the patellar tendon. Our data suggests an association between apophysitis and developing avulsion fracture at the corresponding anatomic location. Apophysitis did not increase the odds of sustaining an avulsion fracture that required surgical intervention.