Abstract
Background
Patients with ongoing symptoms after non-operative treatment of lateral epicondylosis are usually treated with surgical release. Platelet-rich plasma injection is an alternative treatment option. This study aims to determine whether there is a difference in outcome from platelet-rich plasma injection or surgical release for refractory tennis elbow.
Method
Eighty-one patients with a diagnosis of tennis elbow for a minimum of six months, treated with previous steroid injection and a minimum visual analogue scale pain score of 50/100 were randomised to open surgery release (41 patients) or leucocyte rich platelet-rich plasma (L-PRP) (40 patients). Patients completed the Patient-Rated Tennis Elbow Evaluation and Disability of the Arm Shoulder and Hand at baseline, 1.5, 3, 6 and 12 months post-intervention. The primary endpoint was change in Patient-Rated Tennis Elbow Evaluation pain score at 12 months.
Results
Fifty-two patients completed final follow-up. Functional and pain scores improved in both groups. No differences in functional improvements were found but greater improvements in Patient-Rated Tennis Elbow Evaluation pain scores were seen after surgery. Thirteen patients crossed over from platelet-rich plasma to surgery within 12 months, and one surgical patient underwent a platelet-rich plasma injection.
Conclusion
L-PRP and surgery produce equivalent functional outcome but surgery may result in lower pain scores at 12 months. Seventy per cent of patients treated with platelet-rich plasma avoided surgical intervention.
Keywords: platelet-rich plasma, lateral epicondylosis; tennis elbow, extensor carpi radialis brevis, surgery
Background
Tennis elbow (lateral epicondylosis, TE) is a common condition of the upper limb with an incidence of between 4 and 7/1000 patients per year.1 The majority (75–95%) of cases are successfully managed non-operatively with a combination of rest, activity modification and physiotherapy.2 Corticosteroid injection is commonly used as a therapeutic modality; however, the efficacy is questionable, particularly in the longer term.3
Our understanding of the pathophysiology of TE has evolved; the conventional perception of TE as a chronic inflammatory condition having been superseded by an understanding of altered tissue homeostasis with cellular proliferation, matrix degradation and neovascularisation.4,5 Platelet-rich plasma (PRP), which is derived from autologous whole blood is said to improve soft tissue healing via the local secretion of growth factors and recruitment of reparative cells.6 With laboratory evidence to support the use of PRP injections for the treatment of muscle and tendon injuries and degeneration, PRP is beginning to be used clinically in the treatment of rotator cuff repair and muscular and ligamentous strains. The evidence for its clinical efficacy in the treatment of TE includes a demonstrated superiority of L-PRP injections when compared with corticosteroid injections and dry needling procedures.7–15 A systematic review of nine studies comparing PRP injection to other injection-based therapy concluded that L-PRP injections have an important and effective role in the management of TE.16
In a subset of patients, TE proves refractory to conservative treatment measures, with long-term pain and disability lasting between six months and two years.17 A number of surgical techniques have been described for the treatment of refractory TE. The commonly used Nirschl technique of proximal extensor carpi radialis brevis (ECRB) tendinosis excision provides consistently good results in the short and long term, with a low complication risk profile.18
No direct comparison has been made of L-PRP injection and the Nirschl surgical technique for refractory lateral epicondylosis. The aim of this study is to undertake a prospective comparison of patient-rated outcome measures up to one year following L-PRP injection or Nirschl surgical technique for refractory TE.
Materials and methods
Study design
The study design was as an unblinded pragmatic prospective randomised trial performed in a single centre under the supervision of two consultant surgeons. Independent research personnel collected baseline and post-intervention data and entered the study information into an electronic database. Informed consent was obtained from all patients and the patient’s primary care physician was informed of their inclusion in the study.
Ethical approval
Approval for this interventional study was granted by the North West 8 Research Ethics Committee (Reference 10/H1013/56).
Subjects
Patients were identified from routine general practitioner and musculoskeletal clinical assessment and triage services referrals to the orthopaedic service. Patients were included if they had a clinical diagnosis of refractory TE as defined by pain over the lateral epicondyle, with direct palpation and pain at the elbow during resisted wrist extension with a pronated forearm, in whom conservative management had failed and who were being referred for consideration of surgical intervention. Subjects were required to have had symptoms for longer than six months, with severity of pain of at least 50 out of 100 on a visual analogue score (0, no pain; 100, maximum pain possible). Subjects had to have had at least four months conservative management in the form of appropriate physiotherapy and at least one prior corticosteroid injection to ensure consistency in the subject population, as the use of this treatment modality remains prevalent in primary care. A minimum period of two months was mandatory between study intervention and previous corticosteroid injection.
Patients were excluded for the following reasons: pregnancy, a concurrent diagnosis of carpal tunnel syndrome or cervical radiculopathy; systemic disorders such as diabetes, rheumatoid arthritis, or hepatitis and patients who were medically unfit for surgery, or who would not agree to comply with the study follow-up regime.
Participating subjects were given a patient information leaflet to read and informed consent was obtained a minimum of one week after this information had been provided to allow adequate consideration.
Study interventions
For subjects who consented to inclusion self-reported pain in the elbow was assessed on a visual analogue scale with a range 0 (no pain) to 100 (worst pain imaginable) to determine eligibility. A baseline assessment was undertaken using a questionnaire to assess the self-reported function with the Patient-Rated Tennis Elbow Evaluation (PRTEE) and Disability of the Arm Shoulder and Hand (DASH) questionnaires.
Patients were randomised to either L-PRP injection or surgical intervention using 100 opaque envelopes shuffled and sequentially numbered, 50 stating ‘Surgery’ and 50 stating ‘PRP injection’. Because of the clear difference between the two techniques, blinding of the patient or surgeon was not possible.
PRP injection technique
The L-PRP was prepared using the Zimmer Biomet Recover Platelet Separation Kit (Biomet Biologics Inc., Warsaw, Indiana). Twenty-seven millilitres of venous whole blood was drawn from the patient into a 30 ml syringe containing 3 ml of ACD-A (anticoagulant). The mixture was transferred to a single use sterile mini separation tube and placed in a desktop centrifuge for 15 min at 3200 r/min to separate the L-PRP from plasma and red blood corpuscles. During centrifugation 2 ml of 2% plain lidocaine was injected into the dermis and subdermal tissues at the site of maximal tenderness determined by manual palpation. The L-PRP was extracted from the GPS III device using a 10 ml syringe. One to three millilitres of L-PRP was injected via an 18-gauge hypodermic needle into the ECRB tendon using a ‘peppering’ technique. Ultrasound was not routinely used to guide the injection.
Surgical technique
The surgery was undertaken using the technique described by Nirschl and was common to both surgeons.18 Under general or regional anaesthesia, a 3–5 cm curvilinear incision was created centred on the lateral epicondyle. The ECRL tendon was retracted anteromedially to expose the ECRB tendon origin. Any area of tendinosis was excised from the ECRB tendon. After haemostasis, the ECRB aponeurosis was repaired using a vicryl suture and wound closure performed with a subcuticular suture. A bulky bandage was applied for 48 h.
Outcome measures
Early complications or untoward events were recorded at two weeks’ follow-up with wound review. At six weeks, three months, six months and one year, subjects completed a questionnaire to reassess the PRTEE and DASH. Late complications were recorded at these assessments.
If subjects did not attend for follow-up an attempt was made to obtain outcome scores by postal questionnaire, followed by a second questionnaire for those not returned. An attempt was made to contact subjects by telephone at 6 and 12 months if postal questionnaires had not been returned.
Statistical analysis
The primary outcome was defined as the comparison of the mean change in PRTEE pain score from baseline to one-year follow-up for the L-PRP group compared to the surgery group. Secondary outcomes were the comparison of the mean change in PRTEE function score, PRTEE total score, DASH total score and the DASH work score from baseline to one year for the L-PRP group compared to the surgery group.
The power calculation for the primary endpoint was based on the mean change in PRTEE pain score between baseline and one-year follow-up. If the true difference in the experimental and control mean change in baseline for the PRTEE pain score is 15 points at one-year follow-up, a minimum of 45 subjects in each group is necessary to reject the null hypothesis that the population mean change in PRTEE pain score of the experimental and control groups is equal with probability (power) 0.8. The Type I error probability associated with this test of this null hypothesis is 0.05. The study was designed to recruit 100 patients with refractory TE to account for 10% attrition.
Statistical analysis was carried out using SAS (SAS Institute Inc., 2012). A Repeated Measures Analysis of Variance for change from baseline was carried out for the mean change in PRTEE Pain score. Separate analysis was carried out for change in PRTEE function score and PRTEE total score as well as the DASH total score and the DASH work score.
Cross-over
If patients in either arm of the trial were unhappy with their outcome, alternative intervention was offered a minimum of four months after the initial procedure and recorded as a failure of intervention. This was included as a condition of the ethics committee approval. The patients were analysed in the group that they were randomised into according to the intention-to-treat principle.
Patients were withdrawn from the study if they chose to withdraw for any reason, were lost to follow-up, in the event of death, or failure to complete the baseline assessment or any of the follow-up assessments.
Results
One hundred patients with refractory TE were screened. Seventeen were not eligible and were excluded. Eighty-three subjects were randomised. Two subjects completed baseline data but no follow-ups and were excluded from endpoint analysis. Fifty-two subjects who completed both the baseline assessment and one-year follow-up were included in the analysis of the primary endpoint (n = 24 in the L-PRP group and n = 28 in the surgery group) (Figure 1). Follow-up data were available for a further 29 patients at interval time points to enable analysis of changeover time. The baseline demographic data (i.e. age, gender, ethnicity, disease duration and number of prior corticosteroid injection) are presented in Table 1 and baseline patient-reported PRTEE and DASH scores in Table 2. There were no significant differences in the recorded demographic characteristics between the two treatment groups at baseline.
Figure 1.
Patient flow (L-PRP = leucocyte rich platelet-rich plasma).
Table 1.
Baseline demographic data (CSI = corticosteroid injections).
| Surgery (n = 41) | PRP injection (n = 40) | Total (n = 81) | p-value | |
|---|---|---|---|---|
| Age (years) | ||||
| Mean (min–max) | 48 (48–61) | 47 (32–62) | 47 (32–62) | 0.545 |
| Gender number (%) | ||||
| Male | 24 (59) | 23 (58) | 47 (58) | |
| Female | 17 (41) | 17 (42) | 34 (42) | >0.999 |
| Ethnicity number (%) | ||||
| British White | 39 (95) | 39 (98) | 78 (96) | |
| White Italian | 1 (2) | 0 | 1 (1) | |
| Pakistani | 0 | 1 (3) | 1 (1) | |
| Black African | 1 (2) | 0 | 1 (1) | >0.999 |
| Disease duration (months) | ||||
| Mean (min–max) | 22 (6–60) | 23 (7–60) | 22 (6–60) | 0.795 |
| Number of prior CSI | ||||
| Mean (min–max) | 2 (1–5) | 3 (1–8) | 3 (1–8) | 0.314 |
PRP: platelet-rich plasma.
Table 2.
Baseline patient rated scores.
| Surgery (n = 41) | PRP injection (n = 40) | Total (n = 81) | p-value | |
|---|---|---|---|---|
| PRTEE pain (/50) | ||||
| Mean (min–max) | 33 (15–48) | 32 (20–44) | 33 (15–48) | 0.251 |
| PRTEE function (/50) | ||||
| Mean (min–max) | 29 (7–48) | 28 (9–47) | 29 (7–48) | 0.667 |
| PRTEE total (/100) | ||||
| Mean (min–max) | 63 (26–90) | 58 (28–91) | 61 (26–91) | 0.240 |
| DASH total (/100) | ||||
| Mean (min–max) | 45 (9–85) | 47 (9–88) | 46 (9–88) | 0.693 |
| DASH work (/100) | ||||
| Mean (min–max) | 28 (0–81) | 21 (0–88) | 24 (0–88) | 0.321 |
DASH: Disabilities of Arm Shoulder and Hand; PRP: platelet-rich plasma; PRTEE: Patient Rated Tennis Elbow Evaluation.
Within each group there was a significant improvement from baseline in PRTEE pain scores over the 12 months of follow-up (Figure 2, p < 0.001); however, the improvement in PRTEE pain scores was significantly greater in the surgery arm compared to the L-PRP arm (p = 0.004) (Table 3).
Figure 2.
Change in PRTEE pain from baseline over 52 weeks. PRP: platelet-rich plasma.
Table 3.
Change in PRTEE pain score over time (difference between groups p = 0.004, change in PRTEE pain score over time p < 0.001, difference between groups over time p = 0.004).
| Week 0 | Week 6 | Week 12 | Week 24 | Week 52 | |
|---|---|---|---|---|---|
| PRTEE pain (/50) | |||||
| Mean (SD) | |||||
| Surgery | 33 (7) | 23 (12) | 19 (12) | 13 (10) | 9 (11) |
| PRP | 32 (7) | 27 (10) | 22 (13) | 17 (14) | 17 (13) |
PRP: platelet-rich plasma; PRTEE: Patient Rated Tennis Elbow Evaluation.
Within each group, secondary functional outcome measures (PRTEE total, PRTEE function, and DASH total and DASH work) showed significant improvement from baseline in all scores but no significant difference between the groups in the outcome at 12 months (Table 4). In other words, the outcome of L-PRP injection was not significantly different from surgery with regard to PRTEE total, PRTEE function, DASH total and DASH work over 12 months.
Table 4.
Change in PRTEE function score, PRTEE total score, DASH score and DASH work score over time (p value = difference between groups over time).
| Week 0 | Week 6 | Week 12 | Week 24 | Week 52 | p value | |
|---|---|---|---|---|---|---|
| PRTEE function (/50) | ||||||
| Mean (SD) | ||||||
| Surgery | 29 (10) | 20 (13) | 13 (13) | 9 (10) | 7 (8) | |
| PRP | 28 (10) | 24(15) | 19 (14) | 15 (14) | 10 (12) | 0.217 |
| PRTEE total (/100) | ||||||
| Mean (SD) | ||||||
| Surgery | 62 (17) | 42 (25) | 32 (25) | 22 (20) | 16 (19) | |
| PRP | 58 (16) | 49 (24) | 42 (26) | 33 (28) | 26 (24) | 0.113 |
| DASH (/100) | ||||||
| Mean (SD) | ||||||
| Surgery | 45 (18) | 35 (21) | 26 (21) | 22 (18) | 12 (17) | |
| PRP | 47 (17) | 40 (20) | 34 (23) | 30 (24) | 22 (22) | 0.374 |
| DASH work (/100) | ||||||
| Mean (SD) | ||||||
| Surgery | 28 (30) | 21 (29) | 17 (30) | 8 (17) | 6 (9) | |
| PRP | 21 (30) | 20 (32) | 20 (29) | 12 (22) | 10 (22) | 0.967 |
DASH: Disabilities of Arm Shoulder and Hand; PRP: platelet-rich plasma; PRTEE: Patient Rated Tennis Elbow Evaluation.
Fourteen patients had additional interventions within 12 months of the index intervention. One patient in the surgery arm had an L-PRP injection in the same area for persistent symptoms 10.6 months post-surgery (3% cross-over). Thirteen patients in the L-PRP arm underwent surgical treatment for persistent symptoms of TE at a mean time of 6.2 months (3–10.6) 30% cross-over. Data for these patients are included up to the time of their second intervention.
There were no recorded complications associated with the L-PRP injection.
In the surgery arm one patient required a wound debridement three weeks post-operatively and there were no long-term effects.
Discussion
The majority of patients with refractory lateral epicondylosis will experience an improvement in pain symptoms within three months of onset. This recovery can be accelerated by physiotherapy that should include an eccentric loading regime.19–21 For those with ongoing symptoms corticosteroid injection has been in vogue for many years but increasingly evidence demonstrates that the analgesic effect of corticosteroid injection is short lived, recurrence rates are high and the outcomes are no better than a placebo, and corticosteroids may in fact have a detrimental effect on the long-term resolution of the condition.19,22 Following Mishra and Pavelko’s publication of a pilot study in 2006 which indicated improved clinical results with L-PRP when compared with a control injection of bupivacaine with epinephrine, Peerbooms et al.11 and Gosens et al.12 published the one- and two-year results of the same prospective double-blind randomised controlled trial which demonstrated a maintained positive effect of L-PRP injection compared with corticosteroid injection for chronic lateral epicondylitis. Mishra et al.13 followed on from their pilot study with a double-blind, prospective, multicentre randomised controlled trial of 230 patients, showing an improvement in both L-PRP injection and simple needling technique at 12 weeks, with the L-PRP group demonstrating significant clinical improvement when compared with the control group. A recent meta-analysis of trials comparing injection therapies to placebo or a ‘wait-and-see’ policy found that many injection therapies may be beneficial, including PRP, prolotherapy and hyaluronic acid.22 For PRP the weighted mean difference was better than for placebo but the difference was not statistically significant due to wide confidence intervals.
Surgery, performed open, arthroscopically or percutaneous has been offered for patients with ongoing symptoms and is associated with low complication rates. There is evidence of equivalent outcomes for all surgical techniques.23 The Nirschl technique has been shown to be safe and effective and is widely used.18,24 Some surgeons include bone decortication or resection as part of the procedure but this does not improve the effectiveness of the surgery and may increase post-operative pain.25
The present study is the first to directly compare the outcome of L-PRP injection and surgery. The results for change in PRTEE pain score show superiority in favour of surgery. The scores for all other outcomes (i.e. PRTEE function, PRTEE total, DASH total and DASH work score) showed no statistical difference between the L-PRP group and the surgery group. However, as with many studies of TE, obtaining outcome scores for every subject at 12 months was challenging and data were only available for the primary outcome measure in 52 of 81 subjects (64%) in part due to the high cross-over from L-PRP to surgery. In addition to this higher than expected attrition rate, the study design could not include blinding, the injections were not routinely performed under ultrasound guidance and post-intervention physiotherapy protocols were not standardised. These factors may have introduced confounding variables in the analysis of the outcomes.
Importantly, it should be noted that 70% of patients in the L-PRP injection arm of this study had enough improvement that they did not go on to seek surgery within 12 months of the injection. While this does not support a therapeutic benefit of L-PRP injection, it does indicate that the use of L-PRP as a second-line treatment for patients with chronic TE who have failed to respond to non-surgical treatments will reduce the demand for surgical intervention. Surgery can be reserved for the smaller proportion of patients that have ongoing pain symptoms after L-PRP injection.
The study was awarded the Ian Kelly Prize at the British Elbow and Shoulder Society Annual Scientific Meeting 2016.
Authors’ note
Project Sponsor: Wrightington Hospital, Upper Limb Unit. Study Site: Wrightington Hospital Hall Lane Appley Bridge Wigan Lancashire WN6 9EP, UK. The study design was a collaboration between the funder and the investigators. All procedures were carried out by the authors and their team who were all NHS employees. Data were collected and processed by the study team. Biomet was responsible for statistical analysis and the First Author was responsible for the manuscript preparation and decisions regarding publication.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: Funding for this study was received from Zimmer Biomet (Biomet Orthopedics, 56 East Bell Drive P.O. Box 587, Warsaw, Indiana 46581, USA).
Ethical Review and Patient Consent
The study protocol was approved by the North West 8 Regional Ethics Committee and all patient provided written consent for inclusion in the study and use of their data for publication.
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