Allogeneic umbilical cord mesenchymal stem cell conditioned medium (secretome) for treating posterior cruciate ligament rupture: a prospective single-arm study

Background: Outcomes of the current management of posterior cruciate ligament (PCL) rupture are still unsatisfactory. Recent literature demonstrated the efficacy of the paracrine action of mesenchymal stem cells (MSC) in ligament rupture healing. This study aimed to evaluate the outcome of arthroscopic administration of allogeneic umbilical cord-derived MSC (UC-MSC) conditioned medium (secretome) for the treatment of PCL rupture. Patients and methods: This is a prospective study including 12 individuals with PCL rupture grade 1 or 2 who were performed arthroscopy and secretome administrations. The functional and radiologic outcome of the knee was examined one year following intervention. Results: Preoperatively, posterior drawer test revealed three cases of grade 2+ and nine cases of grade 1+, whereas the final follow-up revealed two cases of grade 2+ and ten cases of grade 1+ PCL rupture. At final follow-up, the mean scores for the IKDC, modified Cincinnati, and Lysholm were 90.58 ± 4.30, 90.90 ± 2.15, and 89.42 ± 3.16, respectively. The means of the serial hop tests were 90.33, 94.16, 93.66, and 95.33 for single, triple, crossover, and time hop tests, respectively. Five patients were able to resume competitive sport after an average of 25.8 weeks (25–38). The final MRI analysis revealed that six knees (50%) regained PCL continuity with low signal intensity, five knees (41.6%) returned near-normal PCL continuity, and one knee (8.3%) regained PCL continuity but with deformed outlines. Conclusions: Short-term follow-up indicated that the secretome generated from allogenic UC-MSC produces excellent functional and radiographic results in grade I-II PCL rupture.