If your shoulder has locked up and physical therapy alone is not moving the needle, you have probably wondered whether a shot would help. A 2024 trial asked a cleaner version of that question: what happens when you add an injection plus skilled hands-on joint work on top of the exercise program, instead of choosing one or the other?
The study, briefly
Researchers in Taiwan ran a randomized, single-blind controlled trial in the rehabilitation clinic of a private academic hospital. Seventy adults with frozen shoulder in the painful early “freezing” stage were split into two groups of 35. Both groups received eight weeks of usual-care physical therapy. One group also received hydrodilatation, meaning fluid injected into the joint to stretch the tight capsule from the inside, plus a corticosteroid injection into the bursa under the shoulder muscle, done twice, plus hands-on joint mobilization from a therapist. Outcomes were measured at 1, 2, 4 and 6 months (Huang et al., Archives of Physical Medicine and Rehabilitation, 2024).
The main outcome was the Shoulder Pain and Disability Index, a questionnaire that scores both how much your shoulder hurts and how hard everyday tasks like washing your hair or reaching a shelf have become.
What they found
- The combination group beat physical therapy alone on the main outcome, and the gap was large enough that the odds of it being chance were under 1 in 1,000 (P less than .001 on the Shoulder Pain and Disability Index).
- The same advantage showed up across the board: pain during activity, the Shoulder Disability Questionnaire, and both active range of motion, meaning how far you can lift the arm yourself, and passive range of motion, meaning how far someone else can move it for you. All of those favored the combination group at P less than .001.
- Quality of life moved too. On the SF-36 health survey, the combination group scored better on physical function and bodily pain (P less than .05). That is the difference between a shoulder that measures better and a shoulder that actually feels better to live with.
- The benefit held for at least six months. Between-group differences were significant at every follow-up point: 1, 2, 4 and 6 months. So this was not a short-lived steroid effect that faded once the injections wore off. Eight weeks of treatment, and the gap was still there four months after treatment ended.
The catch
Several, and they matter.
First, this is small. Thirty-five people per arm at a single centre, labeled a Phase I trial by the authors themselves. That is a signal worth following, not a settled answer.
Second, it was single-blind, which means the patients knew perfectly well whether they had received injections. Frozen shoulder outcomes here are mostly self-reported questionnaires, and knowing you got an active procedure reliably nudges those scores upward. Some of the difference is almost certainly expectation.
Third, the published abstract reports P values rather than the size of the difference. So I can tell you the combination group did better, but I cannot tell you whether it was better by 5 points on a 100-point disability score, which you would barely notice, or by 25, which would change your life. For a decision as personal as “should I get a needle in my shoulder,” that gap in reporting is not trivial.
Fourth, and most practically: the combination arm bundled three things together. Fluid distension of the capsule, a steroid in the bursa, and hands-on mobilization. The trial cannot tell you which ingredient did the work, or whether two of the three would have been enough.
What this means for you
Here is how I read it in the clinic.
The framing is “add on,” not “instead of.” This is the single most important detail in the study, and it is the one people misread. The injection group in this trial also received all the usual physical therapy. Nobody in this study got a shot and went home. So the takeaway is not “skip rehab, get injected.” It is that in the painful early stage, a guided injection may make the rehab work better by lowering pain enough for you to actually move.
Stage matters. Every participant was in the freezing stage, the early phase where pain dominates and the shoulder is progressively tightening. If you are further along, in the stiff-but-not-especially-painful stage, this trial does not describe you. Pain-dominant presentations are where injections tend to earn their place, and staging your shoulder by how irritable it is remains the standard way physical therapists decide how aggressive to be (Kelley et al., Journal of Orthopaedic and Sports Physical Therapy, 2009).
The hands-on piece is part of the package. Joint mobilization was included in the combination arm, which is a reminder that skilled manual work is a legitimate ingredient in a frozen shoulder plan, not a nice extra. It has to be paired with a home program you keep doing, though. That is the same principle behind a criteria-based progressive shoulder exercise program: your progression is driven by what your shoulder can currently tolerate, not by the calendar.
Timing is worth asking about. In this trial the difference was measurable by the one-month mark. If you are eight or ten weeks into therapy for a painful, locked-up shoulder and nothing is loosening, that is a reasonable moment to ask your physician whether a guided injection or hydrodilatation is worth adding, rather than grinding on unchanged for another two months.
What I would not do is treat an injection as the whole plan. Steroid injections can settle pain impressively and then leave you with a shoulder that is still stiff, because stiffness responds to graded motion and load, not to medication. The people who do best are the ones who use the pain relief as a window to move more.
If your shoulder is stuck, get eyes on it
Frozen shoulder is one of the conditions where getting the stage right changes the plan entirely, and where a rushed 15-minute visit rarely gets you there. If your shoulder has been locking up and you want an hour of someone actually testing it, mapping which motions are limited and by how much, and leaving you with a staged plan you understand, that is what a comprehensive evaluation is built for. Bring your questions about injections too. Deciding whether to add one is a conversation worth having with real information in front of you.
References
- Huang YH, Kuo YC, Hsieh LF, Tsai CM, Liu YF, Hsieh TL. Efficacy of Combination Therapy (Hydrodilatation and Subdeltoid Bursa Injection With Corticosteroid, Mobilization, and Physical Therapy) vs Physical Therapy Alone for Treating Frozen Shoulder: A Randomized Single-Blind Controlled Trial, Phase I. Archives of Physical Medicine and Rehabilitation. 2024;105(4):631-638. doi:10.1016/j.apmr.2023.11.014. https://pubmed.ncbi.nlm.nih.gov/38092231/
- Kelley MJ, McClure PW, Leggin BG. Frozen shoulder: evidence and a proposed model guiding rehabilitation. Journal of Orthopaedic and Sports Physical Therapy. 2009;39(2):135-148. https://pubmed.ncbi.nlm.nih.gov/19194024/
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