Table 2.

Treatment and outcomes of ultrasound-guided (USG) intrameniscal injections. PRP platelet-rich plasma, OA osteoarthritis, KL Kellgren-Lawrence, MFAT microfragmented adipose tissue, mL, milliliters, PLT, platelet, CaCL2 calcium chloride, KOOS knee injury and osteoarthritis outcome score, MRI magnetic resonance imaging, VAS, visual analog scale, NPS numerical pain scale, IKDC international knee documentation committee; MCID minimum clinically important difference, QOL quality of life

Treatment and tear type	Author	Subjects	Procedure details	PRP characteristics	Outcome measures	Responders (%)	Change in outcome	Follow-up	p value (reported)
Intervention: USG PRP + trephination Control: USG trephination Tear type: Horizontal cleavage tear	Kaminski 2019 [49]	72 (42 PRP, 30 control)	5–10 passes with continuous injection	120 mL blood draw → 6–8 mL PRP Activation: CaCL2 and thrombin PLT and leukocyte calculated but not reported	VAS	MCID: 65 PRP vs 39 control	3.62 ± 0.07 (2.82–4.43) PRP vs 2.36 ± 0.0.09 (3.86–5.20) control	Median 92 weeks (range 54–157 weeks)	p = 0.027 for mean change, p = 0.046 for MCID responders
					KOOS symptom subscale	MCID: 76 PRP vs 48 control	27.93 ± 0.42 (22.89–32.96) for PRP vs 18.38 ± 0.82 (10.81–25.95) for control		p = 0.016 for mean change p = 0.028 for MCID responders
					Arthroscopy free survival		8% PRP vs 28% control		p = 0.032
Intervention: PRP Control: None Tear type: Grade 2 Reicher Posterior horn medial meniscus Ahlback 0–1	Özyalvaç 2019 [50]	23 (8 lost to follow-up)	18-gauge spinal	20 mL blood draw to → 4 mL PRP No activation “4.75 × baseline”	Lysholm score		71.1 ± 6.9 to 91.9 ± 6.6	31.9 months + / − 5.6 (range 19–45)	p < 0.001
					MRI meniscal healing, graded on Reicher scale	67	10: Grade 2 → grade 1 4: Grade 2 → grade 2 1: Grade 2 → grade 3
Intervention: PRP Control: None Tear type: Stoller grade 1 (2), Grade 2 (4) or grade 3(4) without OA	Guenoun 2020 [51]	10	21- or 25-gauge needle 0.5 mL into meniscus, 1.5 mL into meniscal wall and 2 mL perimeniscal space	18 mL draw → 4 mL PRP No activation 1.999 billion ± 616 million platelets	VAS		57 ± 11.6 → 36.3 ± 31.1	6 months	p = 0.18
					KOOS total		56.6 ± 15.7 → 72.7 ± 18.5		p = 0.0007
					Return to sport	100
					MRI		Stable meniscal tears at 6 months in 7/7
Intervention: PRP Control: None Tear type: Degenerative medial body or posterior horn KL: 0–1	DiMatteo 2021 [52]	12	22-gauge needle 3–4 deposits of 0.5–0.8 mL of PRP in meniscus and menisco-capsular junction	2 mL “ACP” Injection repeated 3 × at 2-week intervals No activation No reported dose	VAS	92	6.5 ± 2 to 2.5 ± 2.5	18 months	Baseline to 6 months p = 0.003 6 to 12 months p = 0.004 12 to 18 months stable
					IKDC		50.1 ± 18 to 81.6 ± 13.9		Baseline to 6 months p < 0.001 6 to 12 months p = 0.03 12 to 18 months stable
Intervention: MFAT Control: None Tear type: Multiple locations and types OA present in 21/23 knees	Malanga 2021 [53]	20 patients (23 knees)	18-gauge needle or 22-gauge needle Trephination performed as described by Baria et al	1–2 mL of MFAT in to tear, “the rest” in the joint	NPS	78.9 met MCID	5.45 ± 2.2 to 2.21 ± 2.5	12 months	p < 0.01
					KOOS	MCID met by: 57.9 for KOOS pain and ADL’s 63.2 for KOOS symptoms 73.7 for KOOS sports/rec and QOL	All KOOS subscales saw statistically significant benefit		p < 0.01
Intervention: PRP Control: None Tear type: Multiple locations Horizontal, radial, or complex	Sanchez 2023 [54]			Three injections, every 2 weeks Injection #1 48 mL blood draw → 10–12 mL (dose 2.1 billion-5.2 billion platelets) intrameniscal + intra-articular Injection #2 32 mL blood draw → 8mL PRP (dose 1.7 billion–3.5 billion platelets) intra-articular Injection #3 identical to #1 Activation: CaCl2	KOOS	MCID met by: 69.9 at 6 months 65.2 at 18 months	All KOOS subscales saw statistically significant benefit	18 months	p < 0.0001
					Survival without arthroscopy	90.3			Mean survival 54.3 months