Table 1 Summary:Â the characteristics of included studies
Trial and location | Participants | Average age (years) | Male:female ratio | Design | Minimum follow-up (months) | Intervention/treatment details | PRP injection site | Co-intervention | Outcome measured | Adverse events |
|---|---|---|---|---|---|---|---|---|---|---|
Scott et al. 2019 [16] Multicenter: [USA, Norway, and Italy | 57 persons (athletes) with patellar tendinopathy (Blazina stage IIIB) with symptoms ≥ 6 month | 32 | 6:1 | Randomized, multicenter, prospective, single-blind | 12 | Group 1: Single injection of 3.5 ml of LR-PRP (USG) (n = 19) Group 2: Single injection of 3.5 ml of LP-PRP (USG) (n = 19) Group 3: Single injection of 3.5 ml of NS (USG) (n = 19) | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received strengthening exercises (concentric and eccentric) in a gym-based rehabilitation program: 3 times per week for 6 weeks | VISA-P (knee function and activities), NPRS (pain intensity); GRoC | No serious adverse events However, in Group 2, 1 person reported increased localized patellar tendon pain that prevented the person from participating in the rehabilitation program following injection |
Dragoo et al. 2014 [17] California, USA | 23 persons with patellar tendinopathy with symptoms ≥ 6 weeks | 34 | 19:1 | Randomized, single-center, prospective, double-blind | 6 | Group 1: Single injection of US-guided LR-PRP (6 ml) with dry needling (n = 10) Group 2: Single episode of US-guided dry needling (n = 10) | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received strengthening exercises (eccentric) and flexibility training throughout the study period | VISA (knee function and activities); VAS (pain intensity); SF-12 (QoL); Tegner scale (activity score); Lysholm scale (function and stability) | No adverse events |
Vetrano et al. 2013 [15] Rome, Italy | 46 persons (athletes) with patellar tendinopathy with symptoms ≥ 6 months (mean 18.9 months), un-responsive to previous non-operative treatment | 26.9 | 4:1 | Randomized, single-center, prospective, double-blind | 12 | Group 1: Two injections (2 ml / injection) of PRP over 2 weeks, both injections under USG (n = 23) Group 2: Three sessions of ESWT at 48–72 h interval under USG (n = 23) | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received strengthening (isometric and eccentric) and stretching exercises for 2 weeks | VISA-P (knee function and activities); VAS (pain intensity) Modified Blazina scale (treatment response) | No serious adverse events However, in Group 1, 3 persons reported increased localized patellar tendon pain and discomfort that gradually subsided following injection In Group 2, persons reported transient reddening (no bruising) of the skin following treatment sessions |
Rodas et al. 2021 [20] Barcelona, Spain | 20 persons with patellar tendinopathy with symptoms ≥ 4 months (mean 23.6 months) unresponsive to previous non-operative treatment | 33.9 years | All males | Randomized, single-center, prospective, double-blind | 12 | Group 1: Two injections at an interval of 23 days [1st injection: NS; 2nd injection: BM-MSC suspended in 6 ml solution of Ringer lactate, 2% human albumin, and 5 Mm glucose) (n = 10) Group 2: Two injections at an interval of 23 days [6 ml each] of LP-PRP (USG) (n = 10) | Patellar tendon (at the site of the lesion) and peritendinous (medial and external zone) | All persons, irrespective of group, received the same post-intervention rehabilitation protocol | VISA-P (knee function and activities); VAS (pain intensity); dynamometry (muscle function);000 USG (tendon thickness and vascularity); UTC; MRI | No serious adverse events However, 1 person from each group reported increased pain (gradually subsided) following injection |
Kaux et al. 2019 [18] Belgium | 33 sports persons with patellar tendinopathy with symptoms > 3 months, unresponsive to previous non-operative treatment | 29.4 | All males | Randomized, single-center, prospective study | 3 | Group 1: Single injection of US-guided LP- PRP (6 ml) (n = 18) Group 2: Two episodes (1 week apart) of US-guided hyaluronic acid injections (n = 15) | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received the same rehabilitation program [strengthening and activity exercises (bicycle training) | VAS (Pain intensity); VISA-P (knee function and activities); aAlgometric scores; IKDC scores | No adverse events |
Filardo et al. 2010 [19] Bologna, Italy | 31 persons with patellar tendinopathy (Blazina stage IIIB) with symptoms > 3 months and unresponsive to previous non-operative treatment | 27.1 | All males | Non-randomized, single-center, prospective, open level | 6 | Group 1: Three injections (5 ml each) of PRP at an interval of 15 days (n = 15) and PT (exercise program) Group 2: No active interventions, only PT (exercise program) (n = 16) | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received the same rehabilitation program [stretching, strengthening, and activity exercises (bicycle training) | VAS (pain intensity); EQ-VAS (QoL); Tegner scale (activity score) | No adverse events |
Abdelbary et al. 2018 [21] Cairo, Egypt | 20 persons with patellar tendinopathy with symptoms ≥ 3 months and unresponsive to previous non-operative treatment | 35.8 | 1:3 | Non-randomized, single-center, prospective, double-blind | 12 | Group 1: Single injection (6 ml) of PRP under USG Group 2: Single injection of high-volume injection treatment (10 ml of 0.5% lidocaine + 25 mg hydrocortisone + 30 ml NS under USG guidance | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received the same structured rehabilitation program | VAS (pain intensity) | No adverse events |
Abate et al. 2018 [22] Chieti, Italy | 54 persons with patellar tendinopathy with symptoms ≥ 3 months (mean 11 months) | 38.3 | 1:1 | Non-randomized, retrospective, cohort study, open level | 6 | Group 1: Two injections (4-5 ml each) of PRP, at an interval of 2 weeks, under USG (n = 18) Group 2: Two injections of high-volume injection treatment (10 ml of 2% mepivacaine + 30 ml NS), at an interval of 2 weeks under USG (n = 18) Group 3: Two injections of high-volume injection treatment (10 ml of 2% mepivacaine + 30 ml NS) and 4-5 ml of PRP injections, at an interval of 2 weeks, under USG (n = 18) | Patellar tendon (at the site of the lesion) | All persons, irrespective of group, received the same rehabilitation program (stretching and strengthening [eccentric] for 3 months | VAS (pain intensity); VISA-P (knee function and activities); | No significant adverse |