Platelet rich plasma Injection grafts for musculoskeletal injuries：a review（4）.
Injection procedure
The area of injury is marked while taking into account the clinical exam, and data from imaging studies such as MRI and radiographs. It is recommended to use Dynamic musculoskeletal ultrasound with a transducer of 6～13 Hz in an effort to more accurately Localize the PRP injection. Under sterile conditions, the patient receives a PRP injection with or without approximately 1 cc of 1% Lidocaine and 1 cc of 0.25% Marcaine directly into the area of injury. Calcium chloride and Thrombin may be added to provide a Gel matrix for the PRP to adhere to, potentially maximizing the benefit in the case of a Joint space. We recommend using a Peppering technique spreading in a Clock-like manner to achieve a more expansive zone of delivery. The patient is observed in a supine position for 15–20 min afterwards, and is then discharged home. Patients typically experience minimal to moderate discomfort following the injection which may last for up to 1 week. They are instructed to ice the injected area if needed for pain control in addition to elevation of the limb and modification of activity as tolerated. We recommend Acetaminophen as the optimal analgesic, or Vicodin for break through pain, and dissuade the use of NSAID’s in the early post-injection period (Fig. 6).
Fig. 6
Musculoskeletal ultrasound, common extensor tendinosis
Safety
Any concerns of immunogenic reactions or disease transfer are eliminated because PRP is prepared from autologous blood. No studies have documented that PRP promotes hyperplasia, carcinogenesis, or tumor growth. Growth factors act on cell membranes rather than on the cell nucleus and activate normal gene expression [7]. Growth Factors are not mutagenic and naturally act through gene regulation and normal wound healing feed-back control mechanisms [6]. Relative contraindications include the presence of a Tumor, Metastatic disease, active Infections, or Platelet count < 10 5/ul、Hgb < 10 g/dl. Pregnancy or active Breastfeeding are contraindications. Patients with an Allergy to Bupivicaine (Marcaine) should not receive a local anesthetic with these substances.
The patients should be informed of the possibility of temporary worsening symptoms after the injection. This is likely due to the stimulation of the body’s natural response to Inflammatory mediators. Although adverse effects are uncommon, as with any injection there is a possibility of infection, no relief of symptoms, and neurovascular injury. Scar tissue formation and Calcification at the injection site are also remote risks.
An Allergic reaction or Local toxicity to Bupivacaine HCL or Lidocaine, although uncommon could trigger an adverse reaction. Additionally, when used in Surgical applications for grafting or with Intra-articular injections, PRP may be combined with Calcium chloride and bovine Thrombin to form a gel matrix. This bovine thrombin which is used to activate PRP, in the past has been associated with life threatening coagulopathies as a result of antibodies to clotting factors V, XI, and thrombin [7, 26]. However, since 1997 production has eliminated contamination of bovine thrombin with bovine factor Va. Prior to 1997, Va levels were 50 mg/ml and now are <0.2 mg/ml with no further reports of complications [6].
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