A study of patients with nonunited fractures of long bones found that
injection of platelet-rich plasma (PRP) enhanced the rate of union,
demonstrated by definitive radiographic evidence of healing.
The study, “Platelet Concentrate in Treatment of Non Union of Long
Bones,” was conducted by Vijay Kumar, MD; Anjan Trikha, MD; and Rajesh
Malhotra, MS, who presented the results. It was conducted at the All
India Institute of Medical Sciences in New Delhi, India.
Patients in the study had clinical and radiological signs of nonunion of the long bones, stable internal fixation or stable reduction with plaster immobilization, and more than 90 percent contact between the fracture fragments.
Patients in the study had clinical and radiological signs of nonunion of the long bones, stable internal fixation or stable reduction with plaster immobilization, and more than 90 percent contact between the fracture fragments.
Nonunion was defined as a fracture that had not
shown progressive evidence of healing more than 6 months after injury or
more than 4 months from last fracture site operation. Patients with gap
nonunions, skin infections, or pseudarthrosis; patients unfit for
autologous donation (platelet count <130 × 109/L, or age older than
60 years); and patients with thrombocytopenia or hypofibrogenemia, or
patients taking medicines known to influence platelet function (like
aspirin) were excluded from the study.
PRP preparation and administration
Autologous blood donations were made on the morning of surgery. The PRP
was prepared in the blood bank facility within the hospital and
transferred to the operating room immediately afterward for injection.
PRP preparation involved a series of centrifugation and separation
cycles to concentrate platelets without inducing their premature
activation. Quality control of platelet concentrate in all cases
confirmed a platelet count of 2,000,000/µL and leukocyte reduction.
The 60 patients had a variety of long-bone fractures: tibia (35),
femur (15), humerus (5), and radius (5). Most patients (42) had
undergone open reduction and internal fixation; 18 patients were treated
with closed reduction and internal fixation.
The PRP injections were administered at the site of nonunion—20 mL to
30 mL, depending on the site. Fracture healing was evaluated clinically
and radiologically at serial follow-ups of 2 months after injection and
then every 4 weeks.
Results
Evidence of callus formation was seen in 55 patients by the end of 8
weeks. By 12 weeks, 40 of the 55 patients had bridging trabeculae; the
remaining 15 patients had fracture union by 24 weeks (P < 0.05). Five
fractures (two tibia, two femur, one radius) failed to unite at 24
weeks’ follow-up. These fractures were treated with a revision of
fixation and autologous cancellous iliac bone grafting; all evidenced
union at 3 months postoperatively.
The average time between injury and platelet injection was 9.1 months
(range: 7 to 24 months). In the patients in whom the fracture united,
the platelet injection had been given within 2 to 4 months of diagnosis
of nonunion. However, in the five patients in whom the fracture failed
to unite, the platelet concentrate had been injected 12 months or later
after the diagnosis of nonunion.
Although many PRP studies use a thrombin activator, this study used a
10 percent calcium chloride solution as an activator. According to the
authors, sufficient thrombin is naturally produced in the local trauma
of the needle infiltrating the fracture site. Cultural considerations
also affected the choice of activator; in addition to cost and
availability issues associated with thrombin, its use is unacceptable to
Hindus.
Although the concentration of PRP used was quite high—nearly five
times commonly used values—as was the volume given, the authors believed
it was necessary.
“In nonunion, the process of healing has halted completely and the
local growth factors levels are abysmally low,” they report. “No
previous trials have used such high doses of platelets and we believe
that this could be the possible explanation for the high rates of union
that could be achieved.”
This was not a randomized study, however, and centrifugation was used
for concentrating platelets. Because centrifugation can cause
fragmentation and reduce bioactivity, the authors note that
ultra-filtration may be a more effective method of preparing the PRP.
Also, they note that they cannot conclude that their method would be
effective in the presence of bone defects, because they selected only
fractures with near-total contact between the fracture fragments.
However, “the large sample size of 60 fractures with 55 patients
achieving a complete union at the end of 24 weeks is compelling evidence
supporting this technique,” they conclude.
Disclosure information: Dr. Trikha—Indian Journal of Anaesthesia,
Journal of Anaesthesia and Clinical Pharmacology, Journal of Obstetrical
Anesthesia and Critical Care. Mr. Malhotra and Dr. Kumar report no conflicts.
2012 Annual Meeting News
Tuesday through Friday, February 7 – 10, 2012.
Read more:
Δεν υπάρχουν σχόλια :
Δημοσίευση σχολίου