Abstract
PurposeEffect of ultrasound guided injections of autologous ASCs in chronic recalcitrant patellar tendinopathy.MethodsFourteen patients (16 knees, 12/2 males/females) with chronic, recalcitrant (unsuccessfully treated with nonoperative treatments) insertional PT underwent clinical evaluation and magnetic resonance imaging (MRI) before intervention. Stromal vascular fraction cells (SVF) were expanded by in-vitro culture and characterized by flow cytometry. Players were injected with three bi-weekly injections of ASCs followed by physiotherapy. They underwent serial clinical evaluations during a 12-month period with repeated MRI at 6-month post-injection.ResultsVictorian Institute of sports assessment-patellar tendon questionnaire (VISA-P) scores improved from 43.8 ± 4.9 at baseline to 58.1 ± 7.1, 70.3 ± 7.9 and 78.7 ± 7.5 at 3, 6, and12months follow-up, respectively. (p = 0.0004 comparing each variable with the previous one). Mean Visual analogue pain in sports (VAS-sport) score during practice significantly decreased from 7.4 ± 0.5 at baseline to 5.2 ± 1.5 9 (p = 0.0005), 3.3 ± 1.1 (p = 0.0004) and 1.5 ± 0.7 (P = 0.0004) at 3, 6, and 12 months, respectively. Mean Tegner-scores for patients were 8.0 ± 0.8 before injury and 2.3 ± 0.9 before treatment, thereafter, improving to 4.8 ± 0.8 and 7.2 ± 0.7 at 6- and 12- months, respectively (p = 0.0001). MRI assessed tendon width’ did not change over the first 6 months post-intervention. Significant changes were observed for: tendon thickness (12.8 ± 1.1 to 10.9 ± 0.7, P = 0.0001); tear length (9.3 ± 1.3 to 2.3 ± 0.7, P = 0.0001), tear width (6.3 ± 0.8 to 3.4 ± 0.4, P = 0.0001), and tear thickness (4.6 ± 0.4 to 2.6 ± 0., P = 0.0001) at baseline and 6 months, respectively.ConclusionPatients with recalcitrant insertional PT showed significant clinical improvement and structural repair at the patellar insertional tendinopathy after injections of autologous ASCs. Results of this study are promising and open a new biological therapeutic modality to treat PT.
Highlights
Insertional patellar tendinopathy (PT), commonly known as jumper’s knee, is a highly limiting overuse injury often found in athletes who engage in repetitive forceful loading of the knee extensor apparatus in those with a high volume of training [13]
This study showed that 3 injections of ultrasound guided adipose derived mesenchymal stromal cells (ASCs) were effective in decreasing pain and improving functional and structural repair during the 12 months follow-up of patients with chronic recalcitrant insertional PT
The optimal cell number to treat this condition is not known, a potential advantage of our procedure was that we were able to implant a higher number of mesenchymal stromal cells compared to the number of stromal cells provided by BMAC procedures, that yields less than 1% of mesenchymal stromal cells per procedure [36]
Summary
Insertional patellar tendinopathy (PT), commonly known as jumper’s knee, is a highly limiting overuse injury often found in athletes who engage in repetitive forceful loading of the knee extensor apparatus in those with a high volume of training [13].the prevalence of PT has been shown to be highest among sports involving jumping (e.g.volleyball and basketball) and/or involving running and kicking (e.g.soccer and track and field) [25]. Risk factors like gender (males), amount of hours of training, hamstring flexibility and previous knee injury were reported [26]. A randomized study showed that more than half of the patients still had persisting pain at 12 months follow-up post-surgery [3]. The histopathology underlying this condition mainly involves: microinjury of tendon fibers, mucoid degeneration, necrosis, loss of transitional fibrocartilage tissue that attaches to bone generally without inflammation, and increased apoptotic cell death [24]
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