Article Text

Prolotherapy injections and eccentric loading exercises for painful Achilles tendinosis: a randomised trial
1. Michael J Yelland1,
2. Kent R Sweeting1,
3. John A Lyftogt2,
4. Shu Kay Ng1,
5. Paul A Scuffham1,
6. Kerrie A Evans1
1. 1Griffith University, Logan and Gold Coast, Australia
2. 2Active Health QEII, Christchurch, New Zealand
1. Correspondence to Professor Michael J Yelland, School of Medicine, Griffith University Logan Campus, University Drive, Meadowbrook, Queensland 4131, Australia; m.yelland{at}griffith.edu.au

## Abstract

Objective To compare the effectiveness and cost-effectiveness of eccentric loading exercises (ELE) with prolotherapy injections used singly and in combination for painful Achilles tendinosis.

Design A single-blinded randomised clinical trial. The primary outcome measure was the VISA-A questionnaire with a minimum clinically important change (MCIC) of 20 points.

Setting Five Australian primary care centres.

Participants 43 patients with painful mid-portion Achilles tendinosis commenced and 40 completed treatment protocols.

Interventions Participants were randomised to a 12-week program of ELE (n=15), or prolotherapy injections of hypertonic glucose with lignocaine alongside the affected tendon (n=14) or combined treatment (n=14).

Main outcome measurements VISA-A, pain, stiffness and limitation of activity scores; treatment costs.

## Results

### Patients

Figure 1 demonstrates the flow of participants through the study. A total of 145 people were interviewed by phone, from which 60 were clinically examined. A clinical diagnosis of mid-portion Achilles tendinopathy was made in 50 people. Of these, 43 had ultrasound findings of mid-portion tendinosis and consented to be in the study. A total of 15 participants were allocated to the ELE group, with 14 participants in each of the prolotherapy and combined treatment groups. By the end of the study, three participants had discontinued treatment, all of whom were from the ELE group. One participant had a heart attack, one discontinued because of time restraints and one sustained an unrelated injury during the study. One participant who was assigned to the prolotherapy group did not begin treatment because of work commitments.

Figure 1

CONSORT flow diagram of trial applicants and participants.

The demographic and clinical characteristics of the three groups were similar, although the median duration of pain and the baseline VISA-A score in the combined treatment group were somewhat less than those in the exercise and prolotherapy groups (table 1).

Table 1

Demographic and clinical characteristics and trial treatment details by treatment group

### Treatment

The mean (SD) number of visits per group was 3.3 (1.9) for ELE, 9.5 (2.8) for prolotherapy and 8.7 (2.9) for the combined treatment. The mean (SD) number of injections per visit was 4.4 (1.7) for the prolotherapy group and 4.4 (1.6) for the combined treatment group.

In the ELE group, seven participants returned exercise diaries. Of these, exercise compliance was moderate (25% to 50%) for one, good (50% to 75%) for two and excellent (>75%) for four. In the combined group, nine participants returned exercise diaries. Of these, exercise compliance was moderate for one, good for three and excellent for five.

One adverse event was reported in the trial. A participant in the ELE group had a partial calf tear while playing tennis. An independent sports physician did not attribute this to the ELE programme.

### VISA-A scores

There were significant improvements in VISA-A scores at all times compared with those at baseline for all the groups (p<0.0005; fig. 2). These changes exceeded the MCIC threshold of 20 points by 3 months in all the groups. The mean (95% confidence interval [CI]) increase in VISA-A scores at 12 months was 23.7 (15.6 to 31.9) for ELE, 27.5 (12.8 to 42.2) for prolotherapy and 41.1 (29.3 to 52.9) for combined treatment. The increases from baseline for the ELE group were significantly less than for the combined treatment group at 6 weeks (difference −11.7; 95% Wald CI−3.5 to −19.9; p=0.005) and 12 months (difference −17.3; 95% Wald CI −4.8 to −29.9; p=0.007). There were significant differences between treatment groups over time (Wald χ2 statistics 23.7; df=8; p=0.003).

Figure 2

(A) Mean VISA-A scores by treatment group over 12 months; (B) Treatment differences (‘Combined’ relative to ‘ELE’) with associated 95% CIs.

The percentage within each group achieving the MCIC of 20 points in VISA-A scores from baseline increased significantly over time (p<0.0005) and was generally highest for the combined treatment group (table 2). However, there were no significant differences between groups or between groups over time.

Table 2

Number (%) of participants achieving the minimum clinically important increase of 20 points or more in VISA-A scores from baseline over time by treatment group

The percentage achieving full recovery with a VISA-A score of ≥90 at 12 months was 53% for ELE, 71% for prolotherapy and 64% for combined treatment, but there were no significant differences between groups over time.

### Pain, stiffness and limitation of activity scores

There were significant decreases in pain, stiffness and limitation of activity scores over time within all the groups (p<0.0005, fig. 3). The decreases in pain scores from baseline for ELE were significantly less by a clinically important difference than for prolotherapy at 6 months (difference 2.3; 95% Wald CI 0.3 to 4.4; p=0.028) and for combined treatment at 12 months (difference 2.6; 95% Wald CI 0.4 to 4.8; p=0.02). The difference between the treatment groups over time, however, was not significant overall (Wald χ2 statistics 13.2; df=8; p=0.105). The decreases in stiffness scores from baseline for ELE were significantly less by a clinically important difference than for prolotherapy at 6 months (difference 1.6; 95% Wald CI0.3 to 3.0; p=0.019) and for combined treatment at 6 weeks (difference 2.8; 95% Wald CI 0.8 to 4.8; p=0.007) and 12 months (difference 3.4; 95% Wald CI1.2 to 5.6; p=0.002). The difference between the groups over time was marginally significant (Wald χ2 statistics 16.0; df=8; p=0.043). However, it is cautioned that the significance must be adjusted for multiple testing of the three effects (within-group, between-group and between-group over time). The decreases in limitation of activity scores from baseline for ELE were significantly less by a clinically important difference than for combined treatment at 6 weeks (difference 2.2; 95% Wald CI0.3 to 4.1; p=0.024). The difference between groups over time, however, was not significant overall (Wald χ2 statistics 13.5; df=8; p=0.096).

Figure 3

Mean scores for (A) pain, (B) stiffness and (C) limitation of activity for treatment groups over 12 months. Treatment differences (‘Combined’ relative to ‘ELE’) with associated 95% CIs for (D) pain, (E) stiffness and (F) limitation of activity.

It should be noted that for each of the above-mentioned clinically important differences between the groups, the CIs are very wide; so much smaller differences between the groups cannot be ruled out.

### Satisfaction and global change ratings

There were no significant differences in satisfaction ratings or in PGIC ratings between the groups over time. The percentage reporting “satisfaction” or “extreme satisfaction” with treatment at 12 months was 50% for ELE, 69% for prolotherapy and 71% for the combined treatment. The percentage reporting a PGIC of “much improved” or “very much improved” at 12 months was 75% for ELE, 85% for prolotherapy and 64% for combined treatment.

### Economic analysis

The costs of the specific interventions made up the largest proportion of total costs accounting for 65%, 94% and 73% of the total costs in the ELE, prolotherapy and combined treatment groups, respectively. Compared with ELE, prolotherapy cost an additional $90 in total and combined treatment cost$191 (table 3). For those additional costs, an additional 5.2% of the participants achieved a ≥20-point improvement in VISA-A score from prolotherapy at 12 months, whereas for the combined treatment, an additional 13% achieved this response. From the ICERs, it is apparent that combined treatment offers the best value for money (ie, the additional cost per responder is less than prolotherapy alone).

Table 3

Costs and cost-effectiveness per participant by treatment group

These results were most sensitive to changes in the proportion of responders—for example, when this is reduced in the prolotherapy group by 10%, ELE is superior (lower cost and more responders) to prolotherapy. Reducing the cost of prolotherapy by 20% resulted in prolotherapy being superior to ELE. Reducing the cost of combined treatment by 20% resulted in a 45% reduction in the ICER (and vice versa for increases in the intervention costs). Varying the costs for healthcare by ±20% over the trial and follow-up periods made relatively little difference to the ICERs.

## Discussion

This is the first trial to compare prolotherapy injections with the reference standard treatment of ELE. It offers a comprehensive picture of treatment inputs, clinical outcomes and costs to inform clinical decision making. Although the long-term outcomes summarised by VISA-A scores are similar, there are some differences in treatment inputs and reductions in symptoms. The ELE offers a low cost, self-management programme requiring considerable effort by the patient but with a slower reduction in symptoms. Prolotherapy is a relatively simple office procedure that offers a more time-efficient approach to treatment and a better reduction in pain and stiffness at 6 months but involves the pain of multiple injections, more doctor visits and a higher cost. Combined treatment requires the greatest input from the patient, clinician and health budgets but offers better reductions in pain and limitation of activity at 6 weeks and in pain and stiffness at 12 months and the lowest additional costs per additional responder. This is consistent with other studies comparing single treatment with combined treatment.20 21 The results could indicate some attention bias for those undergoing prolotherapy or combined prolotherapy, as this required an average of 9.5 and 8.7 treatments, respectively, compared with 3.3 visits for the ELE participants.

Strengths of this study include a comprehensive assessment of outcomes over 12 months, successful randomisation and blinding procedures, and a full economic evaluation. The blinded assessor was able to correctly identify the treatment group for 12 (28%) of 43 participants; he did not know in 15 of 43 (35%) cases, and was incorrect for 16 of 43 (37%) participants.

Although a trial design incorporating a no-treatment or at least a waiting list control group was desirable, we decided against this, believing that it would inhibit recruitment, which is already difficult enough in an RCT. We can find only one RCT on Achilles tendinopathy with a wait-and-see group.34 The outcomes for this approach were inferior to ELE in that trial and ELE in our trial.

To our knowledge, the only one other RCT of prolotherapy for tendinosis was for lateral epicondylosis, where injections of sodium morrhuate, glucose and local anaesthetic injections were more effective than saline injections.35 This is the first RCT of prolotherapy for Achilles tendinosis. The improvements in pain at 6–12 months were inferior to those in uncontrolled observational studies of prolotherapy.18 19 This could be because of our use of more comprehensive outcome measures, differences in patient populations, differences in technique or the greater experience of the treating doctors in previous studies. In the Results section, we have compared the treatment effects over time for the primary and the three secondary outcome measures separately. It should be noted that the overall experiment-wise type 1 error rate will be inflated when comparisons arisen from multiple outcome measures are considered.36

This trial provides valuable information for future treatment trials of Achilles tendinosis. Our concurrent collection of VISA-A scores and PGIC ratings allows an estimate of the MCIC for the VISA-A score. The best method for this is the sensitivity–specificity approach, which estimates the difference in VISA-A change scores between the much improved/very much improved group and the remainder.37 38 The MCIC is the threshold of this difference that discriminates between the two groups with equal sensitivity and specificity. Using this method, the MCIC value for the VISA-A questionnaire was 28, somewhat greater than the value used as the benchmark for success in this trial. At an MCIC of 28, the response rates at 12 months become 47% for ELE and 72% for combined treatment, a difference of 25%. This difference reduces the ICER for combined treatment to only \$764 per additional responder.

## Conclusions

In physically active people with painful Achilles tendinosis, most patients show sustained improvements with ELE and prolotherapy used singly or in combination, but that improvements in mean symptom scores occur earlier with prolotherapy and, particularly, with combined treatment than with ELE alone. Improvements in mean VISA-A scores are greater with combined treatment than with ELE alone, but the proportions achieving clinically important improvements in VISA-A scores are similar for all groups. Combined treatment involves a small increase in cost and temporary discomfort from treatment. A larger clinical trial is needed to further explore these findings.

### What is already known on this topic

In painful Achilles tendinosis,

• ELEs are effective but the addition of other treatments may enhance their effect.

• There is level 4 evidence that prolotherapy injections are effective.

• The relative effectiveness of ELEs and prolotherapy used singly and in combination has not been established.

• In painful Achilles tendinosis, prolotherapy and, particularly, ELEs combined with prolotherapy injections give more rapid improvements in symptoms than ELEs alone, but long-term summary outcomes are similar.

• Cost-effectiveness analysis shows that ELEs was the lowest cost treatment, but when combined with prolotherapy, the cost per additional responder was exceptionally good value for money.

## Acknowledgments

The authors thank Michael Yelland, Michael Oei, Vic Wilk and Scott Masters (Musculoskeletal Medicine Practitioners) for assessing and treating the participants in all the three groups; Lyndon Homeming (Podiatrist) for treating the participants in the ELE group; Mark Young, Kent Sweeting (Podiatrist) and Nicole Magner (Physiotheraist) for assessing the applicants; Mark Young (Sports Physician) for independently reviewing the participants who failed to improve; Natasha Morton, Elizabeth Pyke, Gemma Hynard and Xanthe Golenko for administrative assistance and Queensland X-Ray for standardising the ultrasound protocols.

View Abstract

## Footnotes

• Funding The trial was funded by grants from the Musculoskeletal Research Foundation of Australia, the Australian Podiatry Education and Research Foundation and the Griffith University Office of Research. Kent Sweeting was supported by a Primary Health Care Research, Evaluation and Development research fellowship. The funding bodies had no role in the study design; in the collection, analysis and interpretation of data; in the writing of the report or in the decision to submit the paper for publication.

• Competing interests None.

• Ethics approval This study was conducted with the approval of the Griffith University Human Research Ethics Committee.

• Provenance and peer review Not commissioned; externally peer reviewed.

• Patient consent Obtained.

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