This study explored the safety and efficacy of intra-articular injections of autologous platelet lysate (PL) for the treatment of early and intermediate knee osteoarthritis. 48 patients received 3 injections of autologous PL over 12 weeks. Patients reported significant improvements in symptoms, stiffness, pain, daily living activities, and sports scores at 32 and 52 weeks post-treatment compared to baseline, as measured by the KOOS questionnaire. Three patients experienced minor bleeding in the joint but no other complications. The study demonstrated that intra-articular PL injections improved osteoarthritis symptoms and were found to be safe based on the absence of adverse events.

1. ORIGINAL RESEARCH
Safety and Efficacy of Autologous Intra-articular Platelet
Lysates in Early and Intermediate Knee Osteoarthrosis in
Humans: A Prospective Open-Label Study
Jihad Al-Ajlouni, MD,* Abdalla Awidi, MD,†‡ Osama Samara, MD,§ Mahasan Al-Najar, MD,§
Emad Tarwanah, MD,§ Mohannad Saleh, MD,‡ Mohammad Awidi,‡¶ Freh Abu Hassan, MD,*
Mohammad Samih, MD,* Abdulbari Bener, PhD,k# and Manar Dweik, MSc†
Objective: To explore the safety and benefit from intra-articular
autologous platelet lysate (PL) injection in early and intermediate
knee osteoarthritis.
Design: Open-label prospective study.
Setting: Laboratory.
Patients: Adult patients, aged 35 to 70 years, with a history of
chronic pain or swelling on one or both knees and imaging findings
(radiograph or magnetic resonance imaging) of degenerative changes
in the joint of grade I or II on the Kellgren scale were included.
Interventions: Autologous PL was given in the knee joint by
percutaneous intra-articular route every 3 weeks for a total of 3
injections.
Main Outcome Measures: Response was evaluated by non-
normalized Knee Osteoarthritis and Disability Outcome Score (KOOS).
Results: There was a significant improvement in the 5 aspects
evaluated at weeks 32 and 52 compared with baseline. Symptoms
score significantly improved at weeks 32 and 52 from a mean of 11.1
at baseline to 9.0 (P , 0.0001) and 8.7 (P , 0.0001). Stiffness score
significantly improved at weeks 32 and 52 from 2.2 at baseline to 1.7
(P , 0.022) and 1.6 (P , 0.016). Pain score improved at 32 weeks
and at 52 weeks from a baseline of 14.2 to 9.8 (P , 0.0001) and 9.2
(P , 0.0001). Daily Living score improved from 25.0 to 18.7 at 32
weeks (P , 0.0001) and to 15.6 at 52 weeks (P , 0.0001). Sport
score improved from 10.7 to 8.4 at 32 weeks (P , 0.0001) and to 8.1
at 52 weeks (P , 0.0001).
Conclusions: Intra-articular PL significantly improved score of all
aspects evaluated by KOOS. Platelet lysate seems to be a safe
product.
Clinical Relevance: To the best of our knowledge, this is the first
clinical study addressing the use of autologous PL as a treatment
measure for knee osteoarthrosis (KOA). There are no studies
published regarding the treatment of KOA by intra-articular
injections of PL. The previous studies were on the use of platelet-
rich plasma (PRP) treatment for KOA. Platelet-rich plasma use has
been in place for several years, however, a standardized protocol has
not yet been established. Platelet lysate represents a safe, econom-
ical, easy to prepare, and easy to apply source of growth factors in
the treatment of KOA. A head-to-head study is needed to compare
PRP with PL in KOA.
Key Words: osteoarthrosis, platelets lysate, knee, cartilage
(Clin J Sport Med 2014;0:1–5)
INTRODUCTION
Knee osteoarthrosis (KOA) is a common disabling
disease affecting millions of people. It is very prevalent in the
Middle East.1
In its advanced stage, there are no disease-
modifying agents. Measures are needed in early and interme-
diate stage disease to modify the course of the disease and
prevent or slow down the joint degeneration.2
Although the causes of KOA are multifactorial, its
impact on cost and morbidity is huge especially with
increasing age and obesity in the population. Innovative
strategy for early diagnosis and perhaps early treatment may
improve long-term outcomes, reduce morbidity, and contain
the costs of KOA.
Platelet-rich plasma (PRP) has been widely used in the
treatment of mild-to-moderate KOA in both experimental
animal model and in humans. There are many advantages for
this approach including the ease of application, low cost, and
autologous nature of the product.3–6
The therapeutic effects of PRP are probably mediated
through the release of various growth and differentiation
factors. These include platelet-derived growth factor,
transforming growth factor b, fibroblast growth factor, vas-
cular endothelial growth factor, and connective tissue
growth factor.7
Submitted for publication January 19, 2014; accepted August 18, 2014.
From the *Department of Orthopedic Surgery, Jordan University Hospital,
University of Jordan, Amman, Jordan; †Department of Medicine, Thrombosis
Haemostasis Laboratory, University of Jordan, Amman, Jordan; ‡Faculty of
Medicine, Cell Therapy Center, University of Jordan, Amman, Jordan;
§Department of Radiology, Jordan University Hospital, University of Jordan,
Amman, Jordan; ¶Faculty of Medicine, University of Jordan, Amman, Jordan;
kDepartment of Medical Statistics & Epidemiology, Hamad Medical
Corporation, Hamad General Hospital, Doha, Qatar; and #Department of
Public Health, Weill Cornell Medical College in Qatar, Doha, Qatar.
Supported by the deanship of scientific research grant number 1377.
The authors report no conflicts of interest.
Corresponding Author: Abdalla Awidi, MD, Cell Therapy Center, University of
Jordan, Queen Rania St, Amman 11194, Jordan (bdalla.awidi@gmail.com).
Copyright © 2014 by Lippincott Williams & Wilkins
Clin J Sport Med Volume 0, Number 0, Month 2014 www.cjsportmed.com | 1
Copyright ª Lippincott Williams Wilkins. Unauthorized reproduction of this article is prohibited.

2. Because platelets in the PRP product need to be
activated to release their growth factors to produce their
regenerative effect, we thought of an alternative method of
releasing the growth factors in vitro and then injecting them
intra-articularly in the affected knee. To our knowledge, this
is the first study in which such an approach has been used.
The hypothesis of this prospective open-label study was
to explore the safety of percutaneous intra-articular platelet
lysates (PLs) injection and to study the short and intermediate
influence on the KOA using the Knee Osteoarthritis and
Disability Outcome score (KOOS)8
and to observe changes in
knee magnetic resonance (MRI) images. In this study, we
report the safety and KOOS results. The MRI monitoring
results will be the subject of another report.
PATIENTS AND METHODS
A total of 48 adult patients were enrolled during a study
period from February 2012 to July 2012. A written informed
consent was obtained from every patient in accordance with
the declaration of Helsinki. The study was approved by the
Institutional Review Board at the Jordan University Hospital.
All patients were followed for a minimum of 1 year.
Inclusion Criteria and Exclusion Criteria
The following inclusion criteria were used: adult patients
of either gender from age 35 to 70 years, history of chronic (at
least 4 months) pain or swelling of 1 or 2 knees, imaging
findings (radiograph or MRI) of degenerative changes in the
joint of grade I or II on the Kellgren scale.9
Exclusion criteria
were uncontrolled diabetes mellitus, active cancer, active auto-
immune disease, rheumatoid arthritis, major axial deviation
deformity (varus .58, valgus .58), hemorrhagic diseases (coa-
gulopathies), severe cardiovascular diseases, ongoing infec-
tions, immune suppression, patients on therapy with
anticoagulants or inhibitors of platelet aggregation, use of non-
steroidal anti-inflammatory drugs 5 days before blood dona-
tion, and patients with hemoglobin values ,11 g/dL and
platelets values ,150 000/mL. All patients were recruited from
the Orthopedic Department at Jordan University Hospital.
Platelet lysates were prepared at the Hemostasis and Throm-
bosis Laboratory and Cell Therapy Center at University of
Jordan.
Platelet Lysate Preparation
Blood samples were obtained in sterile citrate tubes on
the day of intra-articular injection. A total of 20 mL of blood
were collected in each occasion.
The autologous blood was centrifuged at 1000 rpm for
13 minutes to obtain PRP. A second centrifugation was done
for the PRP at 4000 rpm for 10 minutes to obtain platelet
pellet and supernatant platelet poor plasma (PPP). The pellet
was resuspended in 5 mL of PPP. The suspended pellet was
frozen twice at 2808C, each time for 10 minutes. The sus-
pension was thawed between the first and second freeze and
after the second freeze. The thawed suspension was centri-
fuged at 4000 rpm, and the supernatant was obtained and
filtered with 0.2-mm filters. The filtered product was drawn
in a sterile syringe and used for intra-articular injection.
Platelet count in the initial blood sample and the PRP sample
were obtained.
Treatment Procedure and Follow-up
After the first evaluation including a baseline MRI and
KOOS, filtered PL was given every 3 weeks on days 0, 21,
and 42. The filtered product was drawn in a sterile syringe,
and intra-articular injection was given blindly using a lateral
approach. The injections were administered by a single con-
sultant orthopedic surgeon or 1 assistant under the supervision
of the consultant. Knee Osteoarthritis and Disability Outcome
Score self-administered questionnaire was obtained on weeks 3,
6, 12, 32, and 52. Magnetic resonance imaging was repeated
after 6 months and in some patients after 1 year.
Statistical Methods and Analysis
Data were analyzed using the Statistical Packages for
Social Sciences (SPSS, Version 16.0; SPSS Inc, Chicago, IL).
Data are expressed as mean and SD.
Student t test is used to ascertain the significance of
differences between mean values of 2 continuous variables and
confirmed by nonparametric Mann–Whitney U test. One-way
of analysis of variance was used for comparison of several
group means and to determine the presence of significant dif-
ferences between the group means. The level P , 0.05 was
considered as the cutoff value for significance.
Power Analysis
A power analysis was used to determine the number of
required patients, with the expected minimum response rate of
30% and the accepted margin error of 5% and with a confidence
level of 95%. A sample size of 43 patients was required for
P , 0.05. Therefore, we included 48 patients in our study.
Analysis
Knee Osteoarthritis and Disability Outcome Score
nonnormalized was adopted to validate for patients with knee
osteoarthritis. This score has been previously validated for the
Arabic version.
RESULTS
Subject Characteristics
A total of 48 patients with mean age of 50.2 years and
median of 45 years were included in the study. The mean age
of onset of symptoms was 48.7 years (range, 35-57 years). Of
the 48 patients enrolled, 24 men (50%) with a mean age of 43.3
years (range, 35-58 years) and 24 women (50%) with a mean
age of 49.9 years (range, 42-63) years had primary KOA at the
time they completed the baseline (week 0) questionnaire.
Twenty subjects reported current dominant symptoms
in the right knee and 28 in the left knee. All participants
(24 men, 24 women) completed the 52 weeks.
Platelet Count in Final Sample for Platelet
Lysate
The platelet concentration in the sample prepared for
PL was, on an average, 5.6 times higher than in the initial
Al-Ajlouni et al Clin J Sport Med Volume 0, Number 0, Month 2014
2 | www.cjsportmed.com 2014 Lippincott Williams Wilkins
Copyright ª Lippincott Williams Wilkins. Unauthorized reproduction of this article is prohibited.

3. whole blood platelet count. Thrombocyte count in whole
blood of all subjects ranged between 180 and 302 · 109/L
compared with 1000 and 1700 · 109/L in the modified pre-
pared PL.
Complications
No infection in the joint or skin was detected in any
patient. There was intra-articular bleeding in 3 patients, 2 of
whom required 24 hours of hospitalization for observation
and pain control. All got recovered.
Knee Osteoarthritis and Disability Outcome
Score Results
The mean and SD of KOOS scoring results before
autologous PL injections were 74 6 19.7. After autologous
PL injections at 52 weeks, the mean and SD of scores
decreased to 52.6 6 16.97. Improvement started to seem at
an average of 12 weeks after injection. All data are summa-
rized in Tables 1 and 2.
All patients showed variable improvement in all scores
at weeks 32 and 52, which was significant (P , 0.05) (Figure,
Tables 1 and 2).
DISCUSSION
Knee osteoarthrosis is a common disorder involving the
knee chondral tissue. Although the causes of KOA are
multifactorial, it has huge impact on quality of life and cost
of care, especially with the aging population and with the
increase in obesity in the society. Innovative strategies for
early treatment may improve long-term outcomes, reduce
morbidity, and contain the costs of KOA.
In this study, we are the first to use intra-articular
injection of PL instead of PRP. Recently, there are several
studies describing the use of different platelet-rich products
with the purpose of accelerating tissue repair.10–14
This repair
is attributed to growth factors (GF) released from platelet
granules when activated after intra-articular injection. These
studies showed promising results.15,16
Some authors17,18
have
postulated that autologous platelet injections might provide
the necessary cellular and humoral mediators to induce the
healing cascade and promote knee repair. The rationale was
based on the mitomorphogenic activity of blood GFs and the
inflammatory response induced in an otherwise degenerative
process, leading to improvement of the knee condition. The
effect of autologous platelet injections into the knee has been
evaluated in vitro and in vivo.19
Currently, PRP is widely used experimentally in
different fields of medicine, but the evidence-based use of
PRP in KOA is still in its infancy. Only a few studies report on
work specifically addressing treatment applications in the
orthopaedic field11
with studies showing that the use of intra-
articular injections of PRP in KOA had good short-term results
with no local or systemic adverse events.20
Sanchez et al per-
formed a retrospective observational cohort study (n = 60) to
evaluate the effectiveness of 3 weekly intra-articular injections
of autologous PRP (preparation rich in growth factors [PGRF])
preparation for KOA. The results obtained on WOMAC ques-
tionnaires before treatment and at 5 weeks after treatment
showed a 33.4% success rate on the pain subscale for the
PRGF group. The divergence was attributed exclusively to
the treatment modality (P = 0.004). The improvements in
the functional capacity subscale and overall WOMAC at 5
weeks in favor of PRGF were also associated only with the
treatment modality (P = 0.043 and P = 0.010, respectively).21
The mechanism by which PRP produces improvement
in symptoms of KOA is still subject to debate. Andia and
Maffulli21
showed that frequent PRP administration could
plausibly delay osteoarthrosis (OA) progression and joint
arthroplasty. However, high-quality evidence for the use of
PRP injections is limited to a few randomized trials focused
on pain and function with #6 months of follow-up.4,22,23
Sanchez et al performed a retrospective observational
cohort study (n = 60) to evaluate the effectiveness of 3 weekly
intra-articular injections of autologous PRP (PRGF) prepara-
tion for KOA. The results obtained on WOMAC question-
naires before treatment and at 5 weeks after treatment showed
a 33.4% success rate on the pain subscale for the PRGF
group. The divergence was attributed exclusively to the treat-
ment modality (P = 0.004). The improvements in the func-
tional capacity subscale and overall WOMAC at 5 weeks in
favor of PRGF were also associated only with the treatment
modality (P = 0.043 and P = 0.010, respectively).24
The mechanism by which PRP produces improvement
in symptoms of KOA is still subject to debate. Anitua et al,24
in their study on human synovial cells isolated from 10
patients with osteoarthritis, showed that an intra-articular
injection of PRP could induce an increase in production of
hyaluronic acid structure and promote angiogenesis and cell
proliferation.
TABLE 1. Clinical Outcomes
Variable 0 12 wk 32 wk 52 wk F Test*
KOOS
Symptoms 11.1 6 2.3 9.8 6 2.5 9.0 6 2.4 8.7 6 2.1 13.297
Stiffness 2.3 6 1.3 2.2 6 1.3 1.7 6 1.2 1.6 6 1.2 5.558
Pain 14.2 6 4.7 12.4 6 4.3 9.9 6 4.0 9.2 6 3.8 25.521
Daily living 25.0 6 10.2 22.5 6 9.2 18.7 6 8.7 15.6 6 7.0 17.939
Sports 10.7 6 4.2 9.5 6 3.2 8.4 6 3.1 8.1 6 3.3 8.780
Mean 6 SEM (KOOS). Post hoc test with Bonferroni adjustment for multiple comparisons was performed to investigate the significance in improvement for each variable within
time evaluation: 0 to 12 weeks, 12 to 32 weeks, and 32 to 52 weeks. All post hoc tests, P , 0.05.
*General linear model/repeated-measure test was performed to investigate within-time improvement. All F tests, P , 0.05.
Clin J Sport Med Volume 0, Number 0, Month 2014 Platelet Lysate in Knee Osteoarthrosis
2014 Lippincott Williams Wilkins www.cjsportmed.com | 3
Copyright ª Lippincott Williams Wilkins. Unauthorized reproduction of this article is prohibited.

4. In clinical studies to date, PRP is safe, with no
infections, worsened outcomes, or serious complications
reported. Minor adverse events associated with repeated
intra-articular injections of PRP have been moderate pain,
swelling, and mild effusion that lasted for a few days.4,22,23
To our knowledge, there are no studies published
regarding the treatment of KOA by intra-articular injections
of PL. The main aim of our study was to evaluate prospectively
the short-term safety of PL when given intra-articular and the
effectiveness of PL as measured by nonnormalized KOOS.
Platelet lysate seems to have a positive influence on
early and intermediate KAO. The improvement in KOOS
started as early as 12 weeks after the first injection. More
solid improvement in all the points scored by KOOS showed
statistically significant improvement at week 32 and more so
at week 52 (Tables 1 and 2, Figure). Our results are consistent
with those obtained by Kon et al25
after treating knee degen-
erative cartilage lesions with intra-articular PRP in a series of
100 patients and consistent with those obtained by Gobbi et al
in a prospective randomized study in which 93 patients (119
knees) were studied. There was a significant improvement in
all KOOS scores over time compared with the pretreatment
value (P , 0.001).23
Although worse results have been re-
ported for female patients in other studies,26
we found no
significant difference in the improvement between men and
women (Mann–Whitney U test).
As for the safety, we observed 3 intra-articular bleeding
episodes: 1 after the second injection and 2 after the third
injection. One of the episodes was mild and settled with
simple analgesia and 2 required an overnight hospitalization
for observation. It is not known how much of this is due to
technical cause or due to the PL itself. No additional adverse
reactions, such as acute pain, or neither swelling nor major
complications, such as infection, were noted. This is in
accordance with other study reports15
that emphasized the
safety profile of autologous PRP intra-articular injections.
FIGURE. Knee Osteoarthritis and
Disability Outcome Score improve-
ment from baseline preinjection
evaluation and 12-, 32- and 52-week
follow-up in all patients (P , 0.05).
TABLE 2. Clinical Outcomes of Patients as Measured by KOOS*
KOOS Variable 0 wk 12 wk 32 wk 52 wk 0-32 wk, P 0-52 wk, P
Symptoms 11.1 6 2.3 9.8 6 2.5 9.0 6 2.4 8.7 6 2.1 ,0.0001 ,0.0001
Stiffness 2.2 6 2.3 2.2 6 1.3 1.7 6 1.2 1.6 6 1.2 0.022 0.016
Pain 14.2 6 4.7 12.4 6 4.3 9.8 6 4.0 9.2 6 3.8 ,0.0001 ,0.0001
Daily living 25.0 6 10.2 22.6 6 9.2 18.6 6 8.7 15.7 6 7.1 ,0.0001 ,0.0001
Sport 10.7 6 4.2 9.4 6 3.2 8.5 6 3.5 8.1 6 3.3 ,0.0001 ,0.0001
Mean 6 SEM (KOOS).
*Nonparametric Wilcoxon tests were performed to investigate the significance in improvement for each variable within time evaluation.
Al-Ajlouni et al Clin J Sport Med Volume 0, Number 0, Month 2014
4 | www.cjsportmed.com 2014 Lippincott Williams Wilkins
Copyright ª Lippincott Williams Wilkins. Unauthorized reproduction of this article is prohibited.

5. From our study, we judge PL as a safe product that can be
given in an outpatient setting.
Platelet concentration varies widely in end-product PRP
prepared by different studies,15
and the impact on the efficacy
of the PRP product is not known. The differences in PRP
products could be a reason for the different results in various
clinical applications.26
In our study, we adopted a process to
achieve consistent maximum concentration of platelets to be
used for PL. The final concentration of thrombocytes in our
method was higher in other studies described by Feige et al20
and Marx27,28
who achieved a 4 times increased concentration
of thrombocytes in PRP compared with the whole blood. In
our study, an average concentration of thrombocytes was 5.6
times higher than the concentration in whole blood.
We observed a statistically significant improvement in all
scores evaluated at the end of the therapy. Knee function and
quality of life improved markedly. The majority of patients
returned to their previous activity level and was satisfied with
the results of the treatment. This was probably due to an
increased knee healing potential but needs to be verified through
serial MRI, histological evaluation, and long-term follow-up.
CONCLUSIONS
The results obtained in this study indicate that intra-
articular injection of autologous PL in patients with OA of the
knee are effective in reducing pain and restoring function
without provoking local or systemic adverse events. Platelet
lysate may be particularly useful in elderly OA patients who
may not tolerate nonsteroidal anti-inflammatory drugs and in
patients in whom this treatment is contraindicated. The
simplicity of PL use makes it an attractive option for clinicians
and researchers. Therefore, we recommend a larger placebo-
controlled study before recommending that PL be used as
a first-line treatment for knee OA.
Study Limitations
The limitation of this study includes the absence of
a control group, being open label, small number of patients,
and limited period of follow-up.
The primary imperatives of a new therapy remain the
control of symptoms; because pain is the most pressing
problem in OA, we report here only clinical parameters by
using the KOOS scoring system. Radiographic follow-up
with MRI will be reported in a separate article. This study was
not designed to compare PL with PRP. A new clinical study is
needed to compare these 2 products.
ACKNOWLEDGMENTS
The authors thank the staff of the Orthopedics Clinic at
Jordan University Hospital, Homeostasis and Thrombosis
Laboratory and the Cell Therapy Center at University of
Jordan for their assistance.
REFERENCES
1. Chaaya M, Slim ZN, Habib RR, et al. High burden of rheumatic diseases
in Lebanon: a COPCORD study. Int J Rheum Dis. 2012;15:136–143.
2. Chu CR, Williams AA, Coyle CH, et al. Early diagnosis to enable early
treatment of pre-osteoarthritis. Arthritis Res Ther. 2012;14:212.
3. Jang SJ, Kim JD, Cha SS. Platelet-rich plasma (PRP) injections as an
effective treatment for early osteoarthritis. Eur J Orthop Surg Traumatol.
2013;23:573–580.
4. Patel S, Dhillon MS, Aggarwal S, et al. Treatment with platelet-rich
plasma is more effective than placebo for knee osteoarthritis: a prospec-
tive, double-blind, randomized trial. Am J Sports Med. 2013;41:356–364.
5. Kon E, Mandelbaum B, Buda R, et al. Platelet-rich plasma intra-articular
injection versus hyaluronic acid viscosupplementation as treatments for
cartilage pathology: from early degeneration to osteoarthritis. Arthros-
copy. 2011;27:1490–1501.
6. Sun Y, Feng Y, Zhang CQ, et al. The regenerative effect of platelet-rich plasma
on healing in large osteochondral defects. Int Orthop. 2010;34:589–597.
7. Civinini R, Nistri L, Martini C, et al. Growth factors in the treatment of
early osteoarthritis. Clin Cases Miner Bone Metab. 2013;10:26–29.
8. Roos EM, Roos HP, Lohmander LS, et al. Knee injury and Osteoarthritis
Outcome (KOOS)- development of a self-administered outcome mea-
sure. J Orthop Sport Phys Ther. 1998;28:88–96.
9. Kellgren JH, Lawrence JS. Radiological assessment of osteo-arthrosis.
Ann Rheum Dis. 1957;16:494–502.
10. Anitua E, Sanchez M, Nurden AT, et al. Platelet-released growth factors
enhance the secretion of hyaluronic acid and leads hepatocyte growth
factor production by synovial fibroblasts from arthritic patients. Rheuma-
tology. 2007;46:1769–1772.
11. Mishra A, Pavelko T. Treatment of chronic elbow tendinosis with buff-
ered platelet-rich plasma. Am J Sports Med. 2006;34:1774–1778.
12. Molloy T, Wang Y, Murrell G. The roles of growth factors in tendon and
ligament healing. Sports Med. 2003;33:381–394.
13. Everts PA, Knape JT, Weibrich G, et al. Platelet-rich plasma and platelet
gel: a review. J Extra Corpor Technol. 2006;38:174–187.
14. Sampson S, Gerhardt M, Mandelbaum B. Platelet rich plasma injection
grafts for musculoskeletal injuries: a review. Curr Rev Musculoskelet
Med. 2008;1:165–174.
15. Filardo G, Kon E, Buda R, et al. Platelet-rich plasma intra-articular knee
injections for the treatment of degenerative cartilage lesions and osteo-
arthritis. Knee Surg Sports Traumatol Arthrosc. 2011;19:528–535.
16. Wang-Saegusa A, Cugat R, Ares O, et al. Infiltration of plasma rich in
growth factors for osteoarthritis of the kneeshort-term effects on function
and quality of life. Arch Orthop Trauma Surg. 2011;13:311–317.
17. Taylor MA, Norman TL, Clovis NB, et al. The response of rabbit patellar
tendons after autologous blood injection. Med Sci Sports Exerc. 2002;34:
70–73.
18. Edwards SG, Calandruccio JH. Autologous blood injections for refrac-
tory lateral epicondylitis. J Hand Surg Am. 2003;2:272–278.
19. Kajikawa Y, Morihara T, Sakamoto H, et al. Platelet-rich plasma enhan-
ces the initial mobilization of circulation-derived cells for tendon healing.
J Cell Physiol. 2008;215:837–845.
20. Feige K, Ehrat FB, Kästner SBR, et al. Automated plasmapheresis com-
pared with other plasma collection methods in the horse. J Vet Med A
Phyisol Pathol Clin Med. 2003;50:185–189.
21. Andia I, Maffulli N. Platelet-rich plasma for managing pain and inflam-
mation in osteoarthritis. Nat Rev Rheumatol. 2013;9:721–730.
22. Sánchez M, Fiz N, Azofra J, et al. A randomized clinical trial evaluating
plasma rich in growth factors (PRGF-Endoret) versus hyaluronic acid in
the short-term treatment of symptomatic knee osteoarthritis. Arthroscopy.
2012;28:1070–1078.
23. Cerza F, Carnì S, Carcangiu A, et al. Comparison between hyaluronic
acid and platelet rich plasma infiltration in the treatment of gonarthrosis.
Am J Sports Med. 2012;40:2822–2827.
24. Anitua E, Sanchez M, Orive G, et al. The potential impact of the prep-
aration rich in growth factors (PRGF) in different medical fields. Bio-
materials. 2007;28:4551–4556.
25. Kon E, Buda R, Filardo G, et al. Platelet-rich plasma: intra-articular knee
injections produced favorable results on degenerative cartilage lesions.
Knee Surg Sports Traumatol Arthrosc. 2010; 18:472–479.
26. Gobbi A, Lad D, Karnatzikos G. The effects of repeated intra-articular PRP
injections on clinical outcomes of early osteoarthritis of the knee [published
online ahead of print April 20, 2014]. Knee Surg Sports Traumatol Arthrosc.
doi: 10.1007/s00167-014-2987-4.
27. Marx RE. Platelet-rich plasma (PRP): what is PRP and what is not PRP?
Implant Dent. 2001;10:225–228.
28. Andia I, Sánchez M, Maffulli N. Joint pathology and platelet-rich plasma
therapies. Expert Opin Biol Ther. 2012;12:7–22.
Clin J Sport Med Volume 0, Number 0, Month 2014 Platelet Lysate in Knee Osteoarthrosis
2014 Lippincott Williams Wilkins www.cjsportmed.com | 5
Copyright ª Lippincott Williams Wilkins. Unauthorized reproduction of this article is prohibited.