Introduction: Platelet-rich plasma (PRP) is a promising regenerative medicine treatment option for pain relief and tissue healing in chronic tendinous and cartilaginous injuries. There is very little literature analyzing efficacy of PRP injection for the treatment of hip osteoarthritis and results are conflicting. The purpose of this study was to further assess the short term clinical outcomes of those patients undergoing image-guided intra-articular PRP injections for the treatment of hip osteoarthritis.
Materials and Methods: This was a retrospective case series with IRB approval. Thirty-six patients ages 49-85 (66.0 ± 12.1) years old with chronic hip pain, one or more positive physical exam maneuver(s), diagnosis of hip osteoarthritis on plain radiograph, and failure to improve satisfactorily with conservative treatment (physical therapy, oral medications, and or intra-articular steroid injections) underwent image-guided (ultrasound or fluoroscopic guided) intra-articular hip platelet-rich plasma (PRP) injection. Outcomes were measured at baseline, 2 weeks, 12 weeks, and up to 6 months using the Visual Analogue Scale (VAS) for pain intensity and the Hip Disability and Osteoarthritis Outcome Score (HOOS).
Injection of PRP was performed using either fluoroscopic or ultrasound imaging. Regardless of selection of image guidance, PRP was injected into the intracapsular space until resistance was met; the needle was then slightly withdrawn and the rest of the 8-9cc solution was injected extra-capsularly. Standard post-injection procedure was used for each patient. Day 0-3 consisted of minimizing activity and avoiding the use anti-platelet medications, such as non-steroidal anti-inflammatories and aspirin. During days 4-14 patients were instructed to build tolerance to everyday activities and to stop the use of an assistive walking device. Active range of motion exercises could be performed. Days 15-8 weeks post injection the patients were able to build strength to regain full range of motion and initiate a course of physical therapy.
Results: At 2 weeks, there was a statistically significant improvement (p <0.05) of function in two HOOS subscales: Symptoms and Activities of Daily Living (ADL). There was a statistically significant improvement in all HOOS subscales (Pain, Symptoms, ADLs, Sports/recreation, Quality of life) starting at 12 weeks and persisting at 6 months status post intra-articular PRP injection (Figure 3). A statistical significant improvement in VAS was also observed at 12 weeks and 6 months (VAS baseline 6.9 ± 0.7 [p=0.07, CI -0.03 to 0.83], 12 weeks 2.5 ± 0.2 [p<0.01, CI 4.16 to 4.64], 6 months 3.8 ± 1.2 [p<0.01, CI, 2.64 to 3.56]) following PRP injection for hip osteoarthritis (Figure 1). When the patients were stratified by radiological degree of osteoarthritis using the Kellgren/Lawrence scale, only those with grade I and II hip osteoarthritis showed statistically significant improvements in VAS scores at 6 months post PRP injection (Figure 2).
Discussion: In patients with mild/moderate hip osteoarthritis (Kellgren/Lawrence grade 1-2), platelet rich plasma may provide pain relief and functional improvement up to 6 months. More research is needed to further elucidates the effects of PRP for hip osteoarthritis.