Knee Joint Platelet-Rich Plasma Injections in the Sports Medicine Clinic- SOMOS 2025

r robins, m defoor, m mcdermott s davidson, t dekker

Abstracted accepted for a rapid-fire presentation at the 2025 Society of Military Orthopaedic Surgeons Annual Meeting.

INTRODUCTION: Knee pain resulting from osteoarthritis and chronic overuse injuries is a common complaint in military and general sports medicine clinics, often leading to functional limitations and reduced physical activity levels. As interest in orthobiologics grows, leukocyte-poor platelet-rich plasma (LP-PRP) has gained attention for its potential to reduce inflammation and promote tissue repair with a lower risk of exacerbating joint irritation. With Level I data supporting the use of LP-PRP in mild to moderate knee osteoarthritis, it is increasingly being utilized for a variety of knee pathology.  Real-world data on its clinical effectiveness in military and general sports medicine settings remain limited. This case series examines patient reported outcomes (PROs) of patients treated with a series of 3 LP-PRP knee injections in a military sports medicine setting measuring changes in pain and function over a 12-month time period.

METHODS: One hundred forty-eight patients who underwent a series of 3 LP-PRP injections (Arthrex ACP) over a 3-week period were prospectively followed for 12 months following the injections.  All patients utilized the Military Orthopaedic Tracking Injuries and Outcomes Network (MOTION) patient reported outcomes (PROs) database to record their response to treatment prior to injection, 6 weeks, 12 weeks, 6 months, and 1 year following injection. Functional outcomes were recorded with IKDC, SANE, and PROMIS PF.  Pain Scores were recorded with DVPRS and PROMIS PI.  Numeric variables for each PRO were expressed as mean (±SD) and discrete outcomes as absolute and relative (%) frequencies. Normality and heteroskedasticity of continuous data were assessed with Shapiro-Wilk and Levene’s test respectively. Continuous outcomes were compared with Anova, Welch Anova or Kruskal-Wallis tests according to data distribution. Discrete outcomes were compared with chi-squared or Fisher’s exact test accordingly. The alpha risk was set to 5% and two-tailed tests were used.  Finally, univariate analysis utilizing the Kruskal test allowed for comparison of survey score medians across collected survey time points. The alpha risk was set to 0.05.  Statistical analysis was performed with EasyMedStat (version 3.42).

RESULTS: IKDC scores were associated with higher scores at 6 weeks (β=7.1, [1.01 ; 13.18], p= 0.0224), and trended toward higher scores at 12 weeks (β=5.9, [-0.81 ; 12.6], p= 0.0844) and 6 months (β=6.26, [-0.07 ; 12.6], p= 0.0527).  SANE scores were associated with lower scores at 12 months (β=-9.29, [-17.66 ; -0.93], p= 0.0296) with no association in change of scores in the interim.  PROMIS PF demonstrated an associated improvement at 12 weeks (β=5.17, [0.79 ; 9.54], p= 0.0211) and a trend towards improved scores at 12 months (β=2.47, [-0.37 ; 5.31], p= 0.0876).  Regarding pain, DVPRS was associated with lower pain scores at 6 weeks (β=-1.27, [-2.0 ; -0.55], p= 0.0007), 12 weeks (β=-1.24, [-2.0 ; -0.48], p= 0.0015), and 6 months (β=-0.93, [-1.57 ; -0.29], p= 0.0045).  PROMIS PI trended towards an association with lower pain scores by 12 months (β=-3.11, [-6.35 ; 0.13], p= 0.0596). Finally, 51 active-duty patients reported no change in MOTION readiness scores over the 12-month period (pre-injection: 60.54 (CI±23.12); 1 year: 65.19 (CI±35.72)).

DISCUSSION/CONCLUSON: The results from this study demonstrate that in a military sports medicine patient population, a 3-series of LP-PRP injections modestly improved early function through 6 months of follow-up with possible residual benefit at 12-month follow-up.  Modest pain improvement was noted during the 6 months following treatment, with a trend of improved pain levels diminishing between 6 and 12 months.  Finally, there was no notable change in readiness status for active-duty members undergoing LP-PRP injections for knee pathology over 1 year following treatment. These data points suggest that a series of 3 LP-PRP injections may improve function and reduce pain for 6 months with no decrease in readiness status for active-duty service members.