Inspired by Gupta et al 2022.
Anatomical diagram of the shoulder – anterior aspect (modified from Angelito7: Shoulder anatomy, front view)
PRP – platelet rich plasmakey to acronyms
RCT – randomised controlled (or comparative) trial
RoM – range of movement
SPADI – shoulder pain and disability index
MUA – manipulation under anaesthetic
LOA – lysis of adhesions
BMI – body mass index
Injection techniques were a principal part of my therapeutic approach to MSK conditions 30 years ago and then became a focus of my first SR. In those days the key component of the injection was corticosteroid, and the technical aspects concerned the specific variety of steroid, the dose, and how to get it to where you wanted it safely and with minimum discomfort. I moved over to using filiform needles and drastically reduced my use of steroids but continued to key an eye on the field.
When I was reviewing the literature, it was very rare to find a paper clearly demonstrating the benefit of one injection over another or indeed over saline or water. The latter two are usually considered to be placebo controls but are probably quite efficacious in their own rights.
PRP came along relatively late in my career, and I was already well established as a Western medical acupuncturist, so I never had the opportunity to try it. I confess to being somewhat sceptical, and I do not recall ever seeing definitive efficacy over saline in any clinical condition. This does not seem to have affected the growth in interest of injecting PRP, and when I saw this title in my searches, I thought I should have a look.
This was a parallel arm RCT comparing triamcinolone with PRP in 60 patients with frozen shoulder. It was an open study with a blinded outcome assessor, although the outcomes were both subjective, so I am unsure how much use there was in having a blinded assessor at all. It would have been a different matter if RoM was used as an outcome.
Baseline pain was just under 70 (on a 0 to 100 VAS), and this dropped significantly more in the steroid group at week 4 and week 12. However, by week 24 the tables had turned and the PRP group had a VAS of 14 compared to just under 32 in the steroid group.
The DASH scores were not as dramatic with no significant difference between groups until week 24. Since we know that steroid can be somewhat deleterious in the long term, it is not clear whether positive effects of PRP or negative effects of steroids or some combination of these factors was responsible for the difference between groups.
I followed a reference to a clinical review in the BMJ from 2005. I was interested to read the history and naming of the condition, from periarthritis (1872) to frozen shoulder (1934), and finally to adhesive capsulitis (1945). To quote from the BMJ review:
Although still in use, this more recent term is unfortunate since, although a frozen shoulder is associated with synovitis and capsular contracture, it is not associated with capsular adhesions.
Having had a lot of trouble with shoulder impingement at university, I am pleased to say I have passed the peak age for frozen shoulder (56 years) without suffering from it myself. The condition is slightly more common in women and slightly more common in non-dominant shoulders. Many of us will have treated unfortunate patients who go on to get it in their other shoulder as well. This usually happens within 5 years and occurs in 6-17% of patients.
Needless to say, the BMJ from 2005 does not mention acupuncture, although in recent years the clinical research for acupuncture in chronic shoulder pain has been reasonably favourable,[4,5] so perhaps we will get a mention next time round. Steroid injections, of course, take centre stage, and I was intrigued by a statement in the review that according to a meta-analysis by Hazelman, patients receiving steroid injection earlier in the course of the disease recover more quickly. Well, that was news to me! I have met Brian Hazelman, and I was not aware that he was into meta-analyses, so I followed the reference to find that his paper was published in 1972, long before meta-analyses were invented!
Despite the rather misleading wording in the BMJ review paper, the original paper they reference is really useful, although rather than being a meta-analysis, it is a single centre retrospective study of 130 patients with a painful stiff shoulder (both shoulders were involved in 7 of the 130). The data presented is certainly consistent with early use of steroid being beneficial in terms of the subsequent length of the condition, but the paper actually showed that it was early treatment (within 1 month of onset) rather than the use of steroid that was associated with a shorter duration of the condition.
The BMJ review paper went on to reference a 4-armed RCT of steroids versus physiotherapy versus both, which had a saline injection control group. 93 patients were randomised to 1 of the 4 groups and assessed at 6 weeks, 3, 6, and 12 months using SPADI. The groups receiving both steroid and 12 sessions of supervised physiotherapy or steroid alone were significantly better at 6 weeks and 3 months than saline. By 12 months all groups were effectively the same. Physiotherapy alone did not appear to be better than saline injection, but of course, saline injection is not an inert procedure.
Whilst searching for various of these older papers, I happened across a rather large case-controlled study from the US, published in 2021. It included 728 patients with frozen shoulder who had undergone fluoroscopic glenohumeral corticosteroid injection (739 shoulders injected) and were followed up for at least 1 year. They wanted to know whether or not immediate pain relief following injection was related to the need for further procedures such as MUA, LOA or repeat injection. They did not really find very much, and the overall rate of MUA/LOA was low (5.1%). Oddly, the improvement in pain relief following injection did reach significance as a predictor of MUA/LOA ie the more pain relief you had, the more likely you were to end up having a surgical procedure. This seems counter-intuitive. Patients with diabetes were more likely to have a repeat injection, which seems understandable, but why would patients with lower BMI also be more likely to have a repeat injection? Did the slimmer patients try to use their arms more? This could be a case of stirring too much statistical mud!
Just as I was about to tie things up for this week, I discovered two more papers testing PRP against steroid.[9,10] One 3-armed trial (n=195) from 2017 including ultrasound in the third arm, and one from 2021 (n=60). Results in both favoured PRP, particularly in the longer term.
One last item to cover is frozen shoulder of the hip – as I like to call it. I have seen one case in my career, and I was not aware that it was a recognised condition at the time. I referred the patient to Stanmore for consideration of arthrography. They demurred and just injected the hip with steroids. The patient improved somewhat, and I did not get to write up the case. It is with some wry interest then that I saw a case report of the condition published this year in Orthopedic Reviews. I was amused to see from the introduction that ‘idiopathic capsular restriction of the hip’ was first described by Caroit et al in my year of birth, 1963.
Just about to go to press (WordPress), looking for images to illustrate the piece, and I discover a very comprehensive review of the topic in Nature Reviews Disease Primers, which was published less than a month ago. Obviously, I felt obliged to at least include the reference. I will show all their lovely figures on the Wednesday webinar.
1 Gupta GK, Shekhar S, Haque ZU, et al. Comparison of the Efficacy of Platelet-Rich Plasma (PRP) and Local Corticosteroid Injection in Periarthritis Shoulder: A Prospective, Randomized, Open, Blinded End-Point (PROBE) Study. Cureus 2022;14:e29253. doi:10.7759/cureus.29253
2 Cummings TM, White AR. Needling therapies in the management of myofascial trigger point pain: A systematic review. Arch Phys Med Rehabil 2001;82:986–92. doi:10.1053/apmr.2001.24023
3 Dias R, Cutts S, Massoud S. Frozen shoulder. BMJ 2005;331:1453–6. doi:10.1136/bmj.331.7530.1453
4 Molsberger AF, Schneider T, Gotthardt H, et al. German Randomized Acupuncture Trial for chronic shoulder pain (GRASP) – a pragmatic, controlled, patient-blinded, multi-centre trial in an outpatient care environment. Pain 2010;151:146–54. doi:10.1016/j.pain.2010.06.036
5 Vickers AJ, Vertosick EA, Lewith G, et al. Acupuncture for Chronic Pain: Update of an Individual Patient Data Meta-Analysis. J Pain 2018;19:455–74. doi:10.1016/j.jpain.2017.11.005
6 Hazleman BL. The painful stiff shoulder. Rheumatol Phys Med 1972;11:413–21. doi:10.1093/rheumatology/11.8.413
7 Carette S, Moffet H, Tardif J, et al. Intraarticular corticosteroids, supervised physiotherapy, or a combination of the two in the treatment of adhesive capsulitis of the shoulder: a placebo-controlled trial. Arthritis Rheum 2003;48:829–38. doi:10.1002/art.10954
8 Lesevic M, Awowale JT, Moran TE, et al. Immediate Pain Relief at Time of Corticosteroid Injection for Idiopathic Adhesive Capsulitis as a Predictor of Eventual Outcomes. Orthop J Sports Med 2021;9:23259671211019350. doi:10.1177/23259671211019353
9 Kothari SY. Comparative Efficacy of Platelet Rich Plasma Injection, Corticosteroid Injection and Ultrasonic Therapy in the Treatment of Periarthritis Shoulder. J Clin Diagn Res Published Online First: 2017. doi:10.7860/JCDR/2017/17060.9895
10 Kumar V, Poovaiah R. Randomized controlled trial of functional outcome of periarthritis of shoulder (Adhesive Capsulitis) in a group of 60 patients using intraarticular triamcinolone vs. intraarticular platelet rich plasma. Indian J Orthop Surg 2021;7:57–61. doi:10.18231/j.ijos.2021.009
11 Eberlin CT, Kucharik MP, Cherian NJ, et al. Adhesive Capsulitis of the Hip: A Case Presentation and Review. Orthop Rev 2022;14:37679. doi:10.52965/001c.37679
12 Millar NL, Meakins A, Struyf F, et al. Frozen shoulder. Nat Rev Dis Primer 2022;8:59. doi:10.1038/s41572-022-00386-2
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