Eight patients with chronic patellar tendinopathy were treated with bone marrow aspirate concentrate. At 5-year follow-up, statistically significant improvement was seen for most clinical scores. Seven of eight patients thought that the results of the procedure were excellent although control patients and radiological data were lacking in this study (Pascual-Garrido et al., 2012). Further corroborating clinical studies on the stem cell treatment will need to confirm these positive results of stem cell application to treat tendinopathies.
Chronic patellar tendinopathy is a common problem, which may be associated with long tedious clinical course. It is an overuse disorder, typically occuring in athletes who participate in sports that require jumping, including volleyball and basketball. The primary pathologic process in most painful tendons is degenerative rather than inflammmatory, with failed reparative response and absence of inflammatory cells. Effective conservative intervention includes relative rest, addressing biomechanical issues, eccentric exercise, stretching and movement retraining (Reinking, 2016)
Allogeneic adipose stem cells mixed with fibrin glue were injected into common extensor tendon lesions of 12 participants with chronic lateral epicondylitis; 6 subjects each were administered 10(6) or 10(7) cells in 1 ml. After 52 weeks of follow up, VAS scores progressively decreased and elbow performance scores improved. Tendon defects also significantly decreased through this period (Lee et al., 2015)
Lateral epicondylitis, or tennis elbow, is a condition in which the outer elbow becomes sore and tender at the lateral epicondyle. It is caused by degenerative condition in wrist extensor tendon origin (Kraushaar and Nirschl, 1999). While most patients have spontaneous symptomatic improvement, continuing activity and avoiding mandatory rest may lead to permanent pain. One sixth of patients develop chronic diseases intractable to concervative managements (Coombes et al., 2010; Smidt et al., 2002)
The paucity of controlled studies makes it difficult to tell if the results of preclinical studies would be reproduced clinically. Further well-controlled clinical studies are thus warranted.
Hernigou et al. evaluated the efficiency of biologic augmentation of rotator cuff repair with illiac crest bone marrow stem cells. the prevalence of healing and prevention of re-tears were correlated with the number of mesenchymal stem cells received at the tendon-to-bone interface. Forty-five patients in the study group received concentrated bone marrow stem cells as an adjunct to single-row rotator cuff repair at the time of arthroscopy. The average number of mesenchymal stem cells returned to the patient was 51,000±24,000. Bone-marrow derived mesenchymal stem cells injection as an adjunctive therapy during rotator cuff repair enhanced the healing rate and improved the quality of the repaired surface, as determined by ultrasound and MRI. At the most recent follow-up of 10 years, intact rotator cuffs were found in 39 (87%) of the 45 patients in the mesenchymal stem cells-treated group, but just 20 (44%) of the 45 patients in the control group (Hernigou et al., 2014)
Ellera Gomes et al. investigated the behavior of rotator cuff tears treated with the conventional repair technique with the aid of autologous bone marrow aspirate concentrate in 14 patients. A complete tear of the rotator cuff was repaired and augmented with bone marrow stem cells from illiac crest bone marrow aspirate. At 12 months, 12 of the 14 tears had healed, according to clinical and magnetic resonance imaging results (Gomes et al., 2012)