Atelocollagen vs. Prolotherapy in Partial-Thickness Supraspinatus Tears: A Prospective Randomized Controlled Trial with MRI-Confirmed Outcomes.

Background: Partial-thickness rotator cuff tears (PTRCTs) are a common cause of shoulder pain. The treatment options for this condition vary by tear characteristics and patient needs. Prolotherapy using a hypertonic dextrose solution promotes tissue regeneration by triggering an inflammatory response but may yield variable results. Recently, atelocollagen injections have emerged as a novel treatment for PTRCTs, offering pain relief and functional improvement by serving as a scaffold for tissue repair without causing additional tissue damage.

Objectives: This study aims to compare the efficacy of prolotherapy with hypertonic dextrose to that of atelocollagen injections for managing pain, improving shoulder functionality, and enhancing structural healing at the tear site in patients with PTRCTs. The efficacy of these methods will be evaluated by follow-up magnetic resonance imaging (MRI).

Study Design: A prospective, randomized, observational study.

Setting: Interventional pain management center at a university-affiliated hospital.

Methods: Thirty-four patients with partial-thickness supraspinatus tears (PTSTs) were enrolled and randomly assigned to 2 groups: Group P received prolotherapy, and Group C received atelocollagen injections. The treatments (ultrasound-guided injections) were administered in 3 sessions at one-week intervals. The primary outcome was pain reduction, measured immediately after treatment and at 2 weeks, one month, and 3 months. Secondary outcomes were functional improvements measured with the Korean Shoulder Pain and Disability Index (K-SPADI) and the Shoulder Constant-Murley Scoring System (SCSS) at one and 3 months, as well as comparative MRI evaluations of the supraspinatus tear between the baseline and the 3-month marks.

Results: Of the 34 patients, 28 completed the study. Group C (n = 15) showed significant pain relief from the baseline at both one and 3 months (P = 0.04 and P < 0.01) post-injection, whereas Group P (n = 13) showed significant pain reduction only at 2 weeks after the injection. MRI findings indicated better healing outcomes in Group C, in which improvements were observed in 4 patients as opposed to 0 patients in Group P. Similarly, 10 patients in Group P exhibited aggravated tear signs in follow-up MRI scans, while only 2 patients in Group C showed such aggravations. Functional scores improved in both groups (P < 0.01); however, no significant differences were observed.

Limitations: The 3-month follow-up period was relatively short.

Conclusions: In patients with PTSTs, atelocollagen injections provided more efficient pain relief and demonstrated greater structural improvements than did prolotherapy, as confirmed by MRI. While both treatments were associated with improved shoulder function, atelocollagen seemed to offer the additional benefit of promoting tissue healing. This study supports atelocollagen as a potential therapeutic option for PTST management.