Multiple Platelet-Rich Plasma Injections Versus Single Platelet-Rich Plasma Injection in Early Osteoarthritis of the Knee: An Experimental Study in a Guinea Pig Model of Early Knee Osteoarthritis

BACKGROUND

Platelet-rich plasma (PRP) has emerged as the forerunner among disease-modifying treatment options for early osteoarthritis (OA) of the knee. However, no consensus is available regarding optimum dosing schedules.

PURPOSE

To determine whether multiple injections of PRP (3 injections) provide better short-term and long-term results than a single injection of PRP in a guinea pig model of knee OA.

STUDY DESIGN

Controlled laboratory study.

METHODS

36 Dunkin-Hartley guinea pigs (weighing ~600-800 g) were chosen for this study. The animals were assigned to group DC (disease control group), group G1 (single-PRP group), and group G2 (multiple-PRP group) containing 10, 10, and 12 animals, respectively. Another 4 animals were used for preparation of allogenic PRP. Groups G1 and G2 received 1 and 3 injections of PRP, respectively, at weekly intervals in the intervention knee while the contralateral knee was injected with normal saline. Group DC received no intervention in either knee. Half of the animals from each group (subgroups DC.3, G1.3, and G2.3) were sacrificed at 3 months, and the remaining half (subgroups DC.6, G1.6, and G2.6) were sacrificed at 6 months after intervention. Both knee joints were harvested for histological assessment of articular cartilage and synovium.

RESULTS

The mean synovial scores for groups G1 and G2 were significantly better than those for group DC at 3 months. No difference was found between groups G1 and G2 at 3 months. At 6 months, group G2 had significantly better mean synovial scores than group G1 and group DC. The mean articular cartilage scores in group G2 were significantly better than those in group DC at 3 months. However, at 6 months, no significant difference was found among any of the groups in terms of mean articular scores.

CONCLUSION

Both single and multiple injections of PRP exert similar anti-inflammatory effects on the synovium in the short term. However, this effect is sustained in the long term only for multiple injections. Multiple injections of PRP exert a chondroprotective effect, but only in the short term. This effect is not seen with a single injection of PRP.

CLINICAL RELEVANCE

This study provides insight into the histological basis for the superiority of multiple injections of PRP.

An animal experimental study to assess the core tissue acquisition ability of endoscopic ultrasound-guided histology needles

Background and Objectives:

Acquisition of core tissue on endoscopic ultrasound (EUS)-guided fine-needle aspiration has been regarded as important for establishing an accurate histological diagnosis. Recently, a new 20-gauge histology needle with reverse bevel (ProCore needle) and a 22-gauge needle with 3 novel symmetric heels (Acquire needle) have been developed. The aims of this animal experimental study were to assess the core tissue acquisition (TA) abilities of these new histology needles by comparing them with those of conventional 22-gauge needles and to evaluate the efficacy of suction for these needles.

Materials and Methods:

Three experienced echoendoscopists performed EUS-guided TA with and without suction using 43 types of needles. The amount of obtained tissue specimens and blood contamination was assessed using a scoring system, and the weight of the obtained tissue specimens was measured using an electronic balance.

Results:

The mean amount of core tissue score of the Acquire 22-gauge needle or ProCore 20-gauge needle was significantly higher than that of the conventional 22-gauge needles (Acquire 22-gauge needle vs. conventional 22-gauge needles: P = 0.024; ProCore 20-gauge needle vs. conventional 22-gauge needles: P = 0.001). There was no significant difference in the mean amount of core tissue score between the Acquire 22-gauge needle and the ProCore 20-gauge needle (P = 0.296). In the Acquire 22-gauge needle and ProCore 20-gauge needle, there was no significant difference between the mean amount of core tissue score with suction and that without suction (3.7 ± 0.4 vs. 3.5 ± 0.4, P = 0.734) although blood contamination increased (2.3 ± 0.7 vs. 1.6 ± 0.3, P = 0.061).

Conclusion:

The TA abilities of the ProCore 20-gauge needle and Acquire 22-gauge needle were better than those of the conventional 22-gauge needles. The efficacy of suction for the ProCore 20-gauge needle and Acquire 22-gauge needle was limited.

Effect of unilateral mandibular distraction osteogenesis on mandibular morphology in rabbits with antigen-induced temporomandibular joint arthritis

Aim was to evaluate effect of unilateral distraction osteogenesis (DO) on mandibular morphology in rabbits with antigen-induced arthritis in the temporomandibular joint (TMJ). Forty 8-week-old rabbits were divided into four groups. In groups A,C, arthritis was induced in the right TMJ. Groups A,B underwent DO. Group D served as control group. Cephalometric analysis of mandibular angle, mandibular ramus height, mandibular collum height, and total posterior mandibular height was done on CT-scans preoperatively (T0), after distraction (T1), and at euthanasia (T2). Two-factor ANOVA evaluated the effect of DO and antigen-induced arthritis. No effect of DO or arthritis was observed on mandibular angle or mandibular collum height. For T0-T1, DO increased mandibular ramus height 12.3% (95% CI 5.2-19.4%) in group B (P=0.001) and total posterior mandibular height 6.2% (95% CI 0.3-12.1%) in group A (P=0.04) and 10.0% (95% CI 4.3-15.7%) in group B (P=0.001). For T1-T2, no significant changes occurred in arthritic rabbits (group A). In conclusion, DO increased total posterior mandibular height in rabbits with arthritis. Postoperatively, no significant effect of DO was observed in rabbits with arthritis. Mandibular DO could be a viable treatment modality in patients with TMJ-arthritis.