Abstract
Background:
Patellofemoral pain is a common cause of pediatric knee pain. Most cases improve with activity modification, physical therapy, orthotics, taping/bracing, or medications. Surgery is reserved for refractory cases with structural abnormalities. Patients who exhaust conservative options may benefit from ultrasound-guided injections, though evidence in adolescent athletes is limited. Adults frequently receive intra-articular hyaluronic acid (HA) injection for knee osteoarthritis; HA enhances synovial fluid, reduces inflammation and pain, limits cartilage breakdown, and stimulates endogenous HA production. Pediatric data are limited to one small series (n=16) showing positive results. For patellofemoral pain due to infrapatellar fat pad impingement, steroid injections may reduce pain, swelling, and mechanical impingement, but no adolescent studies exist.
Hypothesis:
Ultrasound-guided intra-articular HA and infrapatellar fat pad steroid injections will provide significant pain relief and facilitate return to sport or activity in adolescent athletes with persistent patellofemoral pain.
Methods:
We conducted a retrospective observational chart review of athletes aged 10–21 years with persistent patellofemoral pain despite standard of care, treated between August 2022 and August 2024 in a single-institution sports medicine clinic. We evaluated outcomes following ultrasound-guided interventions—specifically intra-articular HA and infrapatellar fat pad steroid injections. Primary outcomes included patient-reported pain relief and return/continuation of sport or activity, calculated among those with available follow up data.
Results:
148 adolescent athletes were included (median age 18 years, IQR 16–20 years), of whom 120 (81%) were female and 125 (84%) were competitive athletes. Fifty-four (36%) had prior knee surgery, while 94 (64%) did not. Most patients (126, 85%) experienced symptoms for over 6 months despite conservative therapy including physical therapy and activity modification. Median follow up was 6 weeks (IQR 5–8); no adverse events were reported.
In the non operative subgroup, 73% (62/85) reported pain relief and 78% (52/67) resumed or continued sport/physical activity. Stratified by intervention, pain relief rates were 79% (23/29) for HA, 74% (25/34) for fat pad steroid, and 65% (13/20) for combined injections. Among athletes with patellofemoral pain who underwent prior surgery, 58% (26/45) achieved pain relief and 72% (23/32) returned to or continued activity.
Conclusion:
Ultrasound-guided intra-articular HA and infrapatellar fat pad steroid injections yielded high rates of pain relief and successful return to sport/activity in adolescent athletes with patellofemoral pain refractory to standard care. This effect was less pronounced in the postoperative subgroup. These findings suggest that both interventions are promising non-surgical options. Prospective studies are needed to clarify patient selection criteria, compare treatment efficacy, and assess long-term outcomes.