富血小板血浆可缓解网球肘疼痛

一项为期6个月的随机、双盲、对照试验显示，富血小板血浆(PRP)治疗可使近3/4的网球肘患者的疼痛评分和肘部压痛同时得到改善。

托马斯杰弗逊大学Rothman研究所的Allan Mishra博士及其同事在美国骨科医师协会(AAOS)2013年会上指出，这是第3次有研究显示PRP注射对肱骨外上髁炎(俗称“网球肘”)有效且无明显并发症。

该研究共招募了230名受试者，均症状持续至少3个月，均报告称肱骨外上髁压痛，抗阻伸腕时视觉模拟量表疼痛评分≥50分(满分100分)。所有受试者均对常规治疗(包括物理治疗、非甾体抗炎药和/或类固醇注射)无应答。

Mishra博士及其同事采用Biomet GPS离心机和滤过系统制备了PRP，116例患者接受了该治疗，每人注射2~3 ml PRP。这种PRP含有浓缩血小板和浓缩白细胞，浓度为普通血浆的5~6倍。其余114例患者被分入活性对照组，与PRP组患者一样接受0.25%布比卡因+肾上腺素局部麻醉阻滞，继而由研究者针刺其伸指肌腱，但不注射PRP。

第12周随访时，PRP组患者报告的疼痛评分相对于治疗前基线水平改善了55.1%，而对照组患者报告的疼痛评分改善了47.4%，组间差异不具有统计学显著性(P=0.094)。但12周时次要结局指标有明显组间差异：PRP组37.4%的患者报告称仍有明显肘部压痛，而这一比例在对照组为48.4%(P=0.036)。

24周时，两组在疼痛评分方面的差异达到了统计学显著性：PRP组患者报告的疼痛评分改善了71.5%，而对照组仅改善56.1%(P=0.027)。PRP组患者29.1%的患者报告称仍有明显肘部压痛，仍然显著优于对照组(54%)(P＜0.001)。

此前的2项试验分别平均随访25.6个月和2年，采用了与本项研究相同的方法和PRP系统，在这3项研究中观察到的改善程度也相似。“这3项研究共对350例患者进行了前瞻性、设对照的治疗，均显示出接受PRP治疗的患者结局更佳。”

不过，研究者认为PRP治疗不宜被当做一线治疗。“多数患者对诸如锻炼和休息等常规治疗可产生应答。应当在初始治疗失败的情况下，用PRP代替可的松。”

对于PRP有助于改善网球肘疼痛的潜在机制，研究者指出，临床前研究显示PRP可改善细胞增殖和局部血流，“还可能修饰神经性疼痛受体从而改善临床结局”。这些都有待进一步研究加以阐明。

在这3项研究中均未观察到明显的并发症。“重要的是，在十年间开展的这些研究中，PRP始终显示出极佳的安全性。临床医生和患者可以放心地使用这种PRP治疗慢性网球肘。”

这项研究由Biomet 生物公司资助。所有作者均接受了由多家药企(包括Biomet)提供的资金。

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By: TARA HAELLE, Internal Medicine News Digital Network

Platelet-rich plasma therapy improved both the pain scores and elbow tenderness for almost three-quarters of patients suffering from tennis elbow during a 6-month randomized, double-blind controlled trial.

This study is the third to show a treatment response with no significant complications in patients with lateral epicondylar tendinopathy, commonly known as tennis elbow, from platelet-rich plasma (PRP) injections.

Dr. Allan Mishra and his associates at the Rothman Institute at Thomas Jefferson University, Philadelphia, presented their findings from the trial at the annual meeting of the American Academy of Orthopaedic Surgeons in Chicago.

The 230 study participants had symptoms for at least 3 months and reported tenderness at the lateral epicondyle and pain scored at a minimum of 50 out of 100 on a visual analog scale during a resisted wrist extension. All participants failed to respond to conventional therapy, including a combination of physical therapy, nonsteroidal anti-inflammatory medications, and/or steroid injections, the investigators reported.

Dr. Mishra and his colleagues used a Biomet GPS centrifuge and canister system to prepare a formulation of 2-3 mL of PRP for 116 patients who received the intervention. The PRP contained concentrated platelets and concentrated white blood cells at a concentration five to six times greater than in plasma at baseline.

Both the patients who received PRP and the 114 active controls were given a local anesthesia block of 0.25% bupivacaine with epinephrine before investigators needled the origin of their extensor tendons, delivering the PRP only to the intervention group.

At 12 weeks’ follow-up, patients receiving the PRP injections reported 55.1% improvement in their pain scores, compared with their baseline pain before the procedure, whereas controls reported 47.4% improvement in pain compared with baseline. The findings were not statistically significant (P = .094). The 12-week secondary outcome measurement was statistically significant, with 37.4% of the intervention group reporting significant elbow tenderness, compared with 48.4% of controls reporting significant tenderness (P = .036).

At 24 weeks, the difference in pain scores between the two groups was statistically significant: PRP patients reported 71.5% improvement, whereas controls reported 56.1% improvement (P = .027). Similarly, significant elbow tenderness remained in 29.1% of PRP patients and 54% of the controls (P less than .001).

The two previous trials, one led by Dr. Mishra with a mean 25.6-month follow-up, and another 2-year study, used the same methodology and PRP system as this one and showed similar improvements, said Dr. Mishra. "Together these studies have treated 350 patients in a prospective, controlled fashion with all of the studies showing superiority when patients are treated with PRP," he said.

However, PRP treatment should not be used as a first-line therapy, he said. "Most patients will respond to conservative treatment such as exercise and rest," Dr. Mishra said. "PRP should, however, be used instead of cortisone for patients who have failed initial treatment."

The investigators noted that there are several potential mechanisms by which the PRP helps improve the pain in tennis elbow. Preclinical studies have shown that PRP can improve cell proliferation and others have shown it improves local blood flow, Dr. Mishra said. "Finally, it may be possible that PRP modifies neurogenic pain receptors and thereby improves clinical outcomes," he said. "More research is clearly needed in this area."

As with the other two studies, no significant complications were reported among the participants in this study, the investigators found. "Importantly, these studies were conducted over the course of a decade with an excellent safety profile for PRP," Dr. Mishra said. "Clinicians and patients can now be confident when using this specific form of PRP to treat chronic tennis elbow."

The study was funded by Biomet Biologics. All authors have received funding from a range of industry sources, including Biomet.