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 Table of Contents  
Year : 2023  |  Volume : 6  |  Issue : 1  |  Page : 48-52

Evaluation of the effect of platelet-rich plasma in early osteoarthritis knee using the oxford knee score: A short-term outcome

Department of Orthopaedics, Subbaiah Institute of Medical Sciences, Shivamogga, Karnataka, India

Date of Submission28-Apr-2022
Date of Decision28-May-2022
Date of Acceptance22-Jun-2022
Date of Web Publication27-Dec-2022

Correspondence Address:
Bharath Shekharappa Gadagoli
Subbaiah Institute of Medical Sciences, Shivamogga, Karnataka
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jodp.jodp_41_22

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Introduction: Osteoarthritis (OA) is classically described as a noninflammatory, degenerative joint disease most commonly occurring in the elderly population. It is characterized by the deterioration of articular cartilage and by the formation of new bone at joint surfaces and margins. Our study aims at evaluating the efficacy of intra-articular platelet-rich plasma (PRP) injections in Grade I and II OA knees. Materials and Methods: A total of 46 patients with Grade I and II (Kellgren and Lawrence grading) primary OA knee were enrolled for a prospective study. Prior consent was taken for intra-articular injection of PRP from all patients. The study group was evaluated using the Oxford Knee Score (OKS) at 3 months and 6 months. Results: In our study, we found decreasing pain and improvement in activities of daily living with an increase in OKS at 3 and 6 months, follow-up indicating long-term pain relief, improvement in function, and decreased stiffness. Conclusion: Our study shows that intra-articular injection of PRP is safe and effective in treating Grade I and Grade II OA knee. We also observed improvement in daily living activities and a reduction in pain in patients with OA of the knee treated with two doses of PRP. PRP therapy is an easy, affordable, and minimally invasive treatment, which is practical to administer for treating degenerative OA of the knee with minimal associated adverse events.

Keywords: Osteoarthritis knee, osteoarthritis, Oxford Knee Score, platelet-rich plasma

How to cite this article:
Nitish K, Kubsad S, Sharath J S, Gadagoli BS, Manjunath S, Suresha B, Pai HS. Evaluation of the effect of platelet-rich plasma in early osteoarthritis knee using the oxford knee score: A short-term outcome. J Orthop Dis Traumatol 2023;6:48-52

How to cite this URL:
Nitish K, Kubsad S, Sharath J S, Gadagoli BS, Manjunath S, Suresha B, Pai HS. Evaluation of the effect of platelet-rich plasma in early osteoarthritis knee using the oxford knee score: A short-term outcome. J Orthop Dis Traumatol [serial online] 2023 [cited 2023 Jan 30];6:48-52. Available from: https://jodt.org/text.asp?2023/6/1/48/365280

  Introduction Top

Osteoarthritis (OA) is a disorder involving movable joints characterized by cell stress and extracellular matrix degradation initiated by micro- and macroinjury that activates maladaptive repair responses including proinflammatory pathways of innate immunity. The disease manifests first as a molecular derangement (abnormal joint tissue metabolism), followed by anatomic and/or physiologic derangements (characterized by cartilage degradation, bone remodeling, osteophyte formation, joint inflammation, and loss of normal joint function) that can culminate in illness.”[1]

In India, this degenerative disorder affects up to 20% of the population of different ages. The most common OA of the hip and knee is seen in the age of 50 years and above.[2] Community Oriented Program for Control of Rheumatic Diseases data show that the prevalence of knee pain in rural areas in India is around 13.7% and in urban areas is 6%. The incidence of radiological OA increases with age and corresponds broadly to the age group.[3]

Multifactorial causes including genetic, environmental, metabolic, and biomechanical are believed to play a key role in the development of OA of the knee. Risk factors that are associated with OA knee mostly are old age, obesity, gender, low bone mineral density, joint hypermobility, instability, joint trauma, immobilization, diabetes mellitus, occupation, sports activities, genetic factors, and proprioceptive deficit.[4]

As put forth by the American College of Rheumatology, the criteria for OA include age of 40 years or above, regular experience of knee pain, crepitus on motion coupled with either osteophytes findings on the radiograph, or a combination of morning stiffness lasting for 30 min or less.[5]

Bansal et al. said that the therapeutic benefit of 10 billion platelets in an 8 ml dose of platelet-rich plasma (PRP) had a sustained effect. They hypothesized that high growth factors are because of higher platelet counts, resulting in a better outcome.[6]

Objectives of the study

The objective was to assess the functional efficacy of two doses of PRP clinically in early OA knee using OKS.

  Materials and Methods Top

A prospective study was done over a period of one year from January 2020 to December 2020 at the Department of Orthopaedics, Subbaiah Institute of Medical Sciences and Research Centre, Shivamogga; 46 subjects of both genders of age groups 40–70 years were included in this study. Demographic data such as age, sex, and history were collected through an interview in a predesigned pro forma. Patients were screened and graded for OA knee with the help of plain anteroposterior and lateral radiography of the knee based on Kellgren and Lawrence classification.

Inclusion criteria

Patients aged between 40 and 70 years with Grade I and Grade II OA of the knee based on X-rays of the affected knee in a standing position were included in the study. Kellgren and Lawrence classification was used for grading the severity of OA of the knee.

Exclusion criteria

Patients with thrombocytopenia, septicemia, septic arthritis, overlying cellulitis patients on antiplatelet drugs, diabetes, rheumatoid arthritis, nonspecific arthritis, intra-articular injection of the knee within 1 month, oral corticosteroid use within 4 weeks, posttraumatic injury to the knee, and recent fever or illness were excluded from the study.

Patients who lost to follow-up after intervention were excluded from the study.

Outcome measurement

Evaluation of patients was done basally and at 3 and 6 months of follow-up using Oxford Knee Score prospectively.


Written informed consent was taken from all patients after obtaining ethical clearance from the institutional ethics committee, and the participants were screened based on the inclusion and exclusion criteria. Demographic data and Oxford Knee Score (OKS) were documented. Intra-articular injection of 6 ml of PRP prepared from their own blood was injected to the affected knee into the suprapatellar pouch (for patients with effusion) or through the arthroscopic anterolateral approach to the knee joint, twice at an interval of 4 weeks inside the operating theater with all aseptic precautions. Patients were advised to abstain from nonsteroidal anti-inflammatory drugs and other anti-inflammatory drugs.

Platelet-rich plasma preparation

PRP was prepared by drawing the patient's venous blood of about 35 ml under aseptic precautions. The blood was collected in Safelab® coagulation tubes containing buffered sodium citrate 3.2%. The sample was subjected to centrifugation first at 1500 rpm for 6 min to separate RBCs and a second spin at 3500 rpm for 15 min to concentrate platelets, producing around 5 ml of PRP.

Statistical methods

The primary outcome variables: OKS considered as the outcome parameter. Baseline characteristics such as gender, side involved, and grade of OA were documented. The Wilcoxon signed-rank test was used assess the statistical significance and results are represented using graphs and charts.

P < 0.05 was considered statistically significant.

Statistical analysis was done using IBM, India SPSS version 22.

  Results Top

Average age

The average age in our series was 51.9 years. In our series, the maximum age was 68 years and the minimum age of the patient was 40 years, with a mean age of 51.9 years.

Age-wise distribution of the patients

Age-wise distribution of our series is shown in [Table 1] and [Figure 1].
Table 1: The distribution of ages 40-49, 50-59, and 60-69 years among our study population

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Figure 1: Distribution of age 40–49 years, 50–59 years, and 60–69 years among our study population

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Grade of osteoarthritis knee

Cases were classified according to the Kellgren and Lawrence system for the classification of OA of the knee. The 46 cases in our series constituted 21 Grade I and 25 Grade II cases [Table 2] and [Figure 2].
Table 2: The distribution of grade of osteoarthritis knee based on the Kellgren and Lawrence classification

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Figure 2: Distribution of grade of OA knee based on Kellgren and Lawrence classification. OA: Osteoarthritis

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Oxford Knee Score

Average improvements in Oxford Knee Score at presentation, 3-month follow-up, and 6-month follow-up are shown in [Figure 3].
Figure 3: Change in OKS at the basal level and 3 and 6 months of follow-up. OKS: Oxford Knee Score

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The pre-intervention OKS is shown in [Table 3]. Median being 28.7 with a minimum score of 24 and a maximum score of 33. The scores increased at 3-month follow-up from baseline to a minimum of 26 and a maximum of 37 proving pain relief and improvement in physical function, indicating the efficacy of PRP. At 6-month follow-up, the score further increased from baseline up to 42, suggesting further improvement in OKS.
Table 3: Change in Oxford Knee Score at the basal level and at 3- and 6-month follow-ups

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Statistical analysis

The study shows that PRP injections to the knee in OA were effective at 3 and 6 months follow up with improved OKS compared to baseline and proved to be effective on short-term follow-up. The obtained scores were tabulated in [Table 4] and subjected to the Wilcoxon signed-rank test. The change in baseline OKS compared at 3 and 6 months shows statistically significant results.
Table 4: Wilcoxon signed-rank test comparing baseline Oxford Knee Score with 3rd-month and 6th-month Oxford Knee Score

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  Discussion Top

The study population showed a significant improvement in the OKS when baseline and postinjection scores were compared and were found to be statistically significant.

Uppin et al. reported that the factors in PRP are a variety of polypeptides that play a crucial role in the tissue differentiation, growth, and determining the behavior of all cells, including the chondrocytes. The effectiveness of PRP has been explained as the result of a possible mechanism of active participation of platelet-derived growth factors such as insulin-like growth factor, transforming growth factor beta-I, platelet-derived growth factor, and many other active molecules such as cytokine, chemokines, and arachidonic acid metabolites in the healing process.[7]

The advocacy for PRP use is strong; there are still concerns regarding its clinical efficacy, mainly due to the heterogeneity of preparation methods and resulting products. Single-spinning centrifugation has shown a platelet count of three times that of baseline level, whereas double-spinning centrifugation has shown up to eight times the platelet count baseline level along with high leukocyte count. However, there are very few studies that compare the use of the two techniques of preparation of PRP in early OA knee.[8]

Autologous blood or PRP derived from the blood has been already evaluated for the potential of tissue healing and documented in the literature. Khoshbin et al. in their systematic review evaluated the clinical efficacy of PRP versus control injection for OA Knee and found that as compared with hyaluronan (HA) injection, multiple articular PRP injections may have a beneficial role in the treatment of adult patients at 6 months with mild-to-moderate knee OA.[9]

Spaková et al. in their study recorded statistically significant results in the Western Ontario and McMaster Universities Arthritis Index and Numeric Rating Scale scores in a group of patients who received PRP injections after 3- and 6-month follow-up, hence supporting the use of autologous PRP as an effective and safe method in the treatment of early stages of knee OA.[10]

Yap et al. reported that OKS forms can be easily filled by patients themselves, without the influence of clinicians which removes reporting bias. The questionnaires in OKS are also specific to the knee joint, reducing the influence of unrelated comorbidities on their rating.[11]

Glynn et al., in their study, demonstrated that it is feasible and safe to deliver PRP therapy in a primary care setting for OA knee. The results of the study showed significant pain relief, satisfaction of patients, and improvement in outcome measures, which we can compare with our analysis. Pain at and around the injection site was the prominent side effect of PRP injection noted during the study.[12]

Murray et al. evaluated OKS independently and found it to be the best and most reliable evaluation system for knee assessment, which we have used in our study as a primary tool for assessment, hence validating the use of OKS in knee degenerative arthritis.[13]

Filardo et al.'s meta-analysis stated that PRP injections provide superior outcomes when compared with other injectable options proving the action of platelet concentrates, which goes beyond its mere placebo effect. The observation of this meta-analysis is PRP offers an advantage over other modalities of treatment for OA knee without an increased risk of adverse events, provides a better functional outcome than the placebo effect and the improvement offered by other intra-articular options up to 12 months which correlates with our study findings.[14]

A 1-year follow-up study conducted by Rai et al. observed a significant reduction in the mean pain score at successive follow-ups, which was also evident in our study. Although they observed a small increase in the mean pain scores at 1-year follow-up even then, the pain scores were still significantly lesser than the baseline pain scores at 1 year.[15]

Chen et al., in their summary of meta-analysis, concluded that relief from pain and functional improvement with intra-articular PRP injection is more effective in short-term follow-up (≤1 year). They also observed no significant difference in the risk of an adverse event between PRP and HA or placebo in knee OA.[16]

Subjectively, most patients were more satisfied with the improvement in their gait pattern, which needs further active evaluation in the future.

There were no systemic or long-term complications except mild-to-moderate pain immediately post-intra-articular injection.

The limitation of our study is the need for long-term follow-up to know the changes in the progression of the disease.

Further scope of this analysis could be comparative studies with viscosupplementation, local steroid injections, oral chondroprotective agents, and placebos.

  Conclusion Top

Our prospective study showed improvement in OKS with improved function and reduction in pain in patients with Grade I and Grade II OA of the knee treated with two doses of PRP at 3- and 6-month follow-up. PRP therapy is an easy, affordable, and minimally invasive treatment that is practical to administer for treating degenerative OA of the knee with minimally associated adverse events.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

David C, Lloyd J, Chadwick A. Rheumatological Physiotherapy. 8, illustrated Anybook Ltd, Lincoln, Lincolnshire, United Kingdom Mosby; 1999. p. 83-5.  Back to cited text no. 1
Bhan S. Osteoarthritis. Indian J Orthop 2002;36:1-7.  Back to cited text no. 2
Joshi VL, Chopra A. Is there an urban-rural divide? Population surveys of rheumatic musculoskeletal disorders in the Pune region of India using the COPCORD Bhigwan model. J Rheumatol 2009;36:614-22.  Back to cited text no. 3
Jordan JM, Kington RS, Lane NE, Nevitt MC, Zhang Y, Sower MF, et al. Systemic risk factors for osteoarthritis. In Felson DT, Conference Chair. Osteoarthritisn: New insight. Part 1: The disease and its risk factor. Ann Intern Med 2000;133:637-63.  Back to cited text no. 4
Altman RD. Criteria for the classification of osteoarthritis of the knee and hip. Scand J Rheumatol Suppl 1987;65:31-9.  Back to cited text no. 5
Bansal H, Leon J, Pont JL, Wilson DA, Bansal A, Agarwal D, et al. Platelet-rich plasma (PRP) in osteoarthritis (OA) knee: Correct dose critical for long term clinical efficacy. Sci Rep 2021;11:3971.  Back to cited text no. 6
Uppin RB, Nitish K, Bhuti G, Saidapur SK, Bachchu S. Effectiveness of intra-articular injection of platelet-rich plasma versus triamcinolone in osteoarthritis of knee – A hospital-based randomized clinical trial. IP Int J Orthop Rheumatol 2021;7:6-11.  Back to cited text no. 7
Gato-Calvo L, Magalhaes J, Ruiz-Romero C, Blanco FJ, Burguera EF. Platelet-rich plasma in osteoarthritis treatment: Review of current evidence. Ther Adv Chronic Dis 2019;10:2040622319825567.  Back to cited text no. 8
Khoshbin A, Leroux T, Wasserstein D, Marks P, Theodoropoulos J, Ogilvie-Harris D, et al. The efficacy of platelet-rich plasma in the treatment of symptomatic knee osteoarthritis: A systematic review with quantitative synthesis. Arthroscopy 2013;29:2037-48.  Back to cited text no. 9
Spaková T, Rosocha J, Lacko M, Harvanová D, Gharaibeh A. Treatment of knee joint osteoarthritis with autologous platelet-rich plasma in comparison with hyaluronic acid. Am J Phys Med Rehabil 2012;91:411-7.  Back to cited text no. 10
Yap YY, Edwards KL, Soutakbar H, Fernandes GS, Scammell BE. Oxford knee score 1 year after TKR for osteoarthritis with reference to a normative population: What can patients expect? Osteoarthr Cartil Open 2021;3:100143.  Back to cited text no. 11
Glynn LG, Mustafa A, Casey M, Krawczyk J, Blom J, Galvin R, et al. Platelet-rich plasma (PRP) therapy for knee arthritis: A feasibility study in primary care. Pilot Feasibility Stud 2018;4:93.  Back to cited text no. 12
Murray DW, Fitzpatrick R, Rogers K, Pandit H, Beard DJ, Carr AJ, et al. The use of the Oxford hip and knee scores. J Bone Joint Surg Br 2007;89:1010-4.  Back to cited text no. 13
Filardo G, Kon E, Di Martino A, Di Matteo B, Merli ML, Cenacchi A, et al. Platelet-rich plasma vs. hyaluronic acid to treat knee degenerative pathology: Study design and preliminary results of a randomized controlled trial. BMC Musculoskelet Disord 2012;13:229.  Back to cited text no. 14
Rai D, Singh J, Somashekharappa T, Singh A. Platelet-rich plasma as an effective biological therapy in early-stage knee osteoarthritis: One year follow up. SICOT J 2021;7:6.  Back to cited text no. 15
Chen P, Huang L, Ma Y, Zhang D, Zhang X, Zhou J, et al. Intra-articular platelet-rich plasma injection for knee osteoarthritis: A summary of meta-analyses. J Orthop Surg Res 2019;14:385.  Back to cited text no. 16


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2], [Table 3], [Table 4]


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