Mid-term prognosis of the stromal vascular fraction for knee osteoarthritis: a minimum 5-year follow-up study

Abstract

Background: The short-term safety and efficacy of stromal vascular fraction (SVF) in treating knee osteoarthritis (KOA) have been extensively studied but the mid-term and long-term prognoses remain unknown.

Methods: 126 KOA patients were recruited and randomly assigned to SVF group and hyaluronic acid (HA) group (control group). The scores of visual analogue scale (VAS) and the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) were assessed and compared between the two groups 1, 2, 3, and 5 years after treatment. The endpoint was defined as surgeries related to KOA or clinical scores exceeding the patient acceptable symptom state (PASS).

Results: The VAS and WOMAC scores in the SVF group were significantly better than those in the HA group during the 5-year follow-up after treatment. The average responsive time to SVF treatment (61.52 months) was significantly longer than HA treatment (30.37 months). The adjusted Cox proportional hazards model showed that bone marrow lesion (BML) severity, body mass index (BMI) and treatment were independent risk factors and that the use of SVF reduced the risk of clinical failure by 2.602 times. The cartilage volume was reduced in both the SVF and control groups at 5 years but reduced less in the SVF group.

Conclusions: Up to 5 years after SVF treatment, acceptable clinical state was present for approximately 60% of patients. BML severity and BMI were independent predictors of the prognosis.

Trial registry: This study was retrospectively registered at Chinses Clinical Trial Registry with identifier ChiCTR2100052818 and was approved by ethics committee of the First Affiliated Hospital of Zhejiang Chinese Medical University, number 2013-X-063.

Keywords: Bone marrow lesion; Full-thickness cartilage defect; Knee osteoarthritis; Mid-term follow-up; Prognosis; Stromal vascular fraction.

Fig. 1

Study flow diagram

Fig. 2

Three levels of bone marrow lesions in the red circle position. 0, no BMLs; 1, cover one slice, 2; cover two consecutive slices; 3, cover three or more consecutive slices. A score of 3 was assigned if more than one lesion was present at the same site

Fig. 3

Changes in the VAS score and the WOMAC score during the 5-year period before and after treatment in the SVF group and control group. A The mean VAS score change. B The mean WOMAC total score change. *p value < 0.05, **p value < 0.01, ***p value < 0.001, ns, non-significant (p value > 0.05), compared with pre-treatment

Fig. 4

Kaplan–Meier responsive curve with clinical failure as the endpoint

Fig. 5

MRI evaluation of full-thickness cartilage defect changes at 5 years. A, C Coronal and sagittal images of the medial femur and tibia before injection of SVF. A grade 1 full-thickness cartilage defect can be observed in the circle. B Coronal and sagittal images of the medial femur and tibia 5 years after SVF injection. The full-thickness cartilage defect in the circled area disappeared, and the cartilage edge was smooth