Platelet-Rich Plasma in the Management of Articular Cartilage Pathology

A Systematic Review

Andrew P. Dold, MD; Michael G. Zywiel, MD; Drew W. Taylor, MSc; Tim Dwyer, MBBS; John Theodoropoulos, MD

Disclosures

Clin J Sport Med. 2014;24(1):31-43. 

In This Article

Results

Pathology

The majority of studies (7 of 10) investigated the use of PRP in patients with symptomatic osteoarthritis, with all but one study investigating primary or exclusively degenerative pathology (Table 1). These included 6 studies treating patients with osteoarthritis of the knee 24,26,28–30,32,33 and 1 study treating patients with osteoarthritis of the hip,[30] encompassing a total of 570 joints (530 knees and 40 hips) in 546 patients.

One study investigated the use of PRP in 52 patients with full-thickness chondral lesions of any articular surface in the knee,[31] with defect sizes ranging between 15 and 50 mm2. The defects were reported to be posttraumatic in 5 (10%) patients and degenerative in 47 (90%) patients. One study reported the use of PRP in 5 patients with focal degenerative full-thickness chondral lesions of the patella,[23] ranging in size from 1 to 3 cm2. Finally, 1 study reported the use of PRP in 15 patients with osteochondral lesions of the talus not associated with radiographic evidence of osteoarthritis at a mean of 7.2 years after the injury[27] and who had previously failed nonoperative management.

Preparation and Delivery Techniques

Multiple PRP preparation techniques were reported, with only 2 methods used in more than 1 study (Table 3). In 9 studies, PRP was produced from between 18 and 150 mL of whole blood drawn into collection tubes from the patient,23,24,26–30,32,33 whereas in 1 study, it was obtained via plateletpheresis to a defined (but unreported) volume using an automated cell sorting machine.[31] Of the studies that used collection tubes, between 1 and 3 centrifugation steps were performed to obtain PRP volumes ranging from 2 to 20 mL. Actual platelet concentration assay results were reported for 4 studies.[24,26,31,32] The PRP was activated through the addition of 10% calcium chloride in 6 studies,[24,26,27,29,30,33] whereas unactivated PRP was used in the remaining 4 investigations.

Eight studies investigated direct injection of between 2 and 8 mL of PRP into the affected joint.24,26–30,32,33 Three injections were performed in all cases, at intervals ranging from 1 to 3 weeks. The remaining 2 studies investigated the use of PRP as an adjunct to drilling of focal chondral defects of the knee. In 1 study, gelled PRP solution was added to and contained within the defect by a collagen membrane sutured to the margin.[23] In the second study, the PRP was first soaked into a polyglycolic acid–hyaluronan scaffold that was subsequently placed into the defect and retained with either absorbable pins or gelled PRP fibrin-like adhesive.[31]

Outcome Measures and Follow-up Times

A range of clinical, radiographic, and pathological assessment methods were reported. All studies used 1 or more primarily patient-centered outcome scores to assess the effectiveness of PRP in the treatment of osteochondral pathology. The Western Ontario and McMaster Universities' Arthritis Index (WOMAC) was the most commonly reported clinical score used in 3 studies. A visual analogue scale (VAS) was the most commonly used assessment of pain reported in 4 studies. No other clinical outcome measure was used in more than 2 studies. Six studies reported outcomes at final follow-up times of 6 months or less,[26,27,29,30,32,33] with 1 study reporting outcomes at 5 weeks posttreatment only.[29] No study reported outcomes more than 24 months after treatment.

Radiographic outcomes were reported for 3 studies, with 1 using ultrasound and 2 performing magnetic resonance imaging assessment of cartilage thickness at the 6-month to 24-month follow-up.[23,28,31] Finally, tissue samples were obtained in 1 study in a subset of patients at the 9-month follow-up for microscopic evaluation.[31] Of the 4 studies that included a comparison group,[26,27,30,32] 3 intra-articular injections of hyaluronic acid were given to all control patients at the same time intervals as the study group PRP injections. Only clinical results were assessed in these 4 studies, with final follow-up times of 6 months in 3 studies and 5 weeks in the fourth.

Clinical Results

All the assessed studies assessed outcomes using joint-specific clinical scores, general health assessment scores, pain scales, or a combination of these measures. Significant improvements in WOMAC; Lequesne, Ankle and Hindfoot; Knee Injury and Osteoarthritis Outcome; and International Knee Documentation Committee (IKDC) scores were consistently reported up to 6 months after intra-articular PRP injection compared with both hyaluronic acid injection and/or preintervention values for both degenerative osteoarthritis and focal chondral lesions (Table 4). Filardo et al[24] reported significantly improved IKDC scores up to 24 months after intra-articular knee injection of PRP for knee osteoarthritis, although the authors noted that the scores peaked at the 6-month follow-up, with subsequent significant decline. No studies treating knee osteoarthritis or focal chondral lesions with PRP failed to show significant improvements and/or differences in joint-specific clinical scores, although Sanchez et al[29] did not report comparative data between PRP and hyaluronic acid groups.

Four studies investigating knee osteoarthritis reported significantly improved patient-reported health status scores measured using either Short Form 36 (SF-36) or EuroQol Visual Analogue Scale (EQ VAS) instruments after PRP injection (Table 5).[24,26,32,33] These differences were maintained up to the 6-month final follow-up in 3 studies,[26,32,33] with significantly better scores reported in patients treated with PRP compared with hyaluronic acid in 2 reports.[26,32] Filardo et al[24] reported significantly improved EQ VAS scores at a final follow-up of 24 months compared with baseline, although the authors again noted that the scores peaked at the 6-month follow-up and subsequently declined.

With regard to pain scores, 6 studies treating both degenerative osteoarthritis and focal chondral lesions consistently demonstrated improved results when compared with baseline at follow-up times up to 12 months for both denegerative osteoarthritis and focal chondral lesions (Table 6).[23,27,28,30,32,33] Dhollander et al[23] demonstrated improved pain scores up to 24 months after microfracture of patellar lesions supplemented with local application of PRP, although this study included only 5 patients and no statistical comparison was performed. Spakova et al[32] reported significantly lower pain scores at final follow-up in patients with knee osteoarthritis treated with PRP compared with hyaluronic acid. Sanchez et al reported significantly lower pain scores at 6-month follow-up in patients with hip osteoarthritis treated with PRP injections, although the presentation of scores was limited to box plots only, without the inclusion of actual numeric mean scores or ranges. Finally, Mei-Dan failed to demonstrate a significant difference between PRP and hyaluronic acid injections in patients with osteochondral lesions of the talus despite considerably different mean pain scores at final follow-up, although this may be because of a lack of adequate powering of the study, with only 15 patients per treatment group (mean VAS scores at final follow-up of 0.9 vs 3.1; P > 0.05) (Table 6).[27]

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