Can injections realistically delay joint surgery?

If exercise-based physiotherapy, weight management and regular pain relief are no longer enough, a common next-step question is: can an injection buy time before a hip or knee replacement, and what does “buying time” usually look like in practice?

Injections generally sit in the middle ground: they aim to reduce pain and improve function so that day-to-day activity and rehabilitation can continue, rather than “curing” arthritis or reliably restoring cartilage.

A practical way to think about “delay” is that injections may be used as one of three bridging strategies:

• A short bridge (weeks to a few months) to calm a flare and get moving again (often the role of a corticosteroid “rescue” injection).
• A medium bridge (often months in some studies) aimed at longer-lasting symptom improvement, most consistently reported for PRP in early–moderate knee osteoarthritis. [ai4scholar:1c1e4d7c5fe9913fa21b2bc37f3cf2b8aaf8f271]
• A joint-preservation “adjunct” for selected focal cartilage problems, where BMAC is reported in small clinical series and techniques vary across studies (so certainty about comparative benefit remains limited). [ai4scholar:e33a7af52c45c3877043b1022130e61fb1402c71] [ai4scholar:f4478d2297066878e856ec067e85c7c81afc95f3]

The main injection types discussed here are:

• Corticosteroid: anti-inflammatory, typically fastest onset, usually shortest duration.
• Hyaluronic acid (“gel”): a viscosupplement aimed at lubrication/shock absorption; in hip osteoarthritis, RCT-level evidence suggests symptom improvements are typically modest and vary between studies. [ai4scholar:3b87a6bc94e7f6921bff806987956248b15a73fb] [ai4scholar:44abbca81b747db54ea6cfa5a16a9e2057b91ece]
• PRP: blood-derived growth-factor concentrate; comparative knee evidence suggests both PRP and steroid can help, with PRP often showing a more durable pattern in later follow-up in several trials and reviews. [ai4scholar:1c1e4d7c5fe9913fa21b2bc37f3cf2b8aaf8f271]
• BMAC: a marrow-derived biologic with heterogeneous preparation and delivery techniques across published studies; discussed more often in joint-preservation contexts, but higher-quality comparative trials are still limited. [ai4scholar:e33a7af52c45c3877043b1022130e61fb1402c71]

Across hip and knee pathways, the foundations still come first—education, physiotherapy-led strengthening and activity modification, weight management, and oral/topical analgesics—before injections are considered for persistent, intrusive symptoms.

Where do hip gel injections sit for night pain?

Night-time hip pain (the sort that wakes people at 2–3am) often drives interest in a “gel injection” when physiotherapy and tablets are no longer enough, but surgery still feels like a big step. In hip osteoarthritis, that “gel” is hyaluronic acid (HA), a lubricating, shock-absorbing fluid placed into the hip joint under image guidance. It is a symptom-management treatment; it does not repair worn cartilage.

The best randomised evidence suggests HA can reduce overall hip pain and improve function scores for a few months, but the average effect is usually modest. A level I systematic review of hip HA RCTs (982 participants; mean age ~62) reported improvements in WOMAC and VAS outcomes over follow-up measured in months, with outcomes varying across studies; it also reported some differences by molecular weight at around 4–6 months, but not consistent separation between HA formulations across all timepoints. [ai4scholar:3b87a6bc94e7f6921bff806987956248b15a73fb]

At the same time, an updated systematic review/meta-analysis focused on high–molecular-weight HA found no significant differences versus active comparators (including corticosteroids) or saline on pain and function outcomes across included hip RCTs—supporting the practical interpretation that HA is not reliably superior to other injectables on average. [ai4scholar:44abbca81b747db54ea6cfa5a16a9e2057b91ece]

HA still appears in some real-world hip pathways because observational cohorts report that selected patients can feel noticeably better. For example, retrospective series of repeated ultrasound-guided Hylan G‑F 20 injections followed over a mean of 31 months reported average pain reductions of around 2–3 points (on a 0–10 scale), with better responses in primary hip OA than secondary inflammatory OA. Another cohort following patients for 24 months reported reduced analgesic use (around 21%) alongside symptom improvement. These are not randomised comparisons, so placebo effects and selection bias are hard to exclude, but they help explain why HA is sometimes used selectively as a “try-and-see” bridge when the goal is to reduce overall pain (and potentially night disturbance) without moving straight to hip replacement. [ai4scholar:5ee3bc642d06ca2021ef8af61878bf3353ad195a] [ai4scholar:591da5431c67e1f07a9ac002a60b3b5a19d30e34]

Night pain specifically remains an evidence gap: most hip HA studies report overall pain and function scores rather than separating day pain from sleep disruption, so any claim about nocturnal benefit has to stay cautious and based on global symptom change rather than direct measurement.

How do PRP and steroid injections compare for knee arthritis?

In day-to-day knee osteoarthritis care, the choice between a cortisone (corticosteroid) injection and platelet-rich plasma (PRP) is often about timing: rapid short-term calm versus a better chance of longer-lasting improvement over the next 6–12 months. In several randomised comparisons—particularly in Kellgren–Lawrence grade II–III knees—the two treatments can both help, but their “shape” of benefit tends to differ. [ai4scholar:1f198155781f789bb2dff67afebc2d728b8db570] [ai4scholar:d0609ea33cfaa93cc4e1994ecdc4db67cc0be741]

PRP is made from a small sample of the patient’s own blood, processed to concentrate platelets and the growth factors they release, then injected into the knee joint. The clinical aim in knee arthritis studies is symptom improvement—pain, stiffness and function—rather than a “rescue” effect in the first few days.

A 2025 systematic review of randomised trials concluded that both PRP and corticosteroid injections are effective and generally safe for knee osteoarthritis, with several included trials suggesting PRP gives more durable relief beyond around 3–6 months, even though not every head-to-head comparison shows clear statistical superiority for PRP on the main outcomes. [ai4scholar:1c1e4d7c5fe9913fa21b2bc37f3cf2b8aaf8f271]

Corticosteroid injections are potent anti-inflammatories, commonly used when synovitis is driving pain and swelling and the priority is speed (often measured over the first 1–3 weeks in trials). Across randomised studies, steroids tend to produce faster early pain relief, while PRP tends to catch up—and in many trials edge ahead—on pain and function measures by 6 months and sometimes out to 12 months. [ai4scholar:1f198155781f789bb2dff67afebc2d728b8db570] [ai4scholar:d0609ea33cfaa93cc4e1994ecdc4db67cc0be741]

In practical terms, two common scenarios lead to different choices even with the same evidence base:

• A person facing a fixed near-term demand—such as a long-haul flight in 3 weeks or a family wedding next month—often prioritises a treatment more likely to settle symptoms quickly, which is where a corticosteroid “flare” injection is frequently considered in practice (recognising it is symptom control, not cartilage repair).
• A person trying to stay active over the coming 6–12 months—often with earlier-grade OA—may place more weight on durability, where PRP has repeatedly shown a favourable pattern in trials and recent reviews.

Safety profiles also differ in emphasis. PRP trials and reviews generally report mild, self-limiting post-injection soreness or swelling and no serious safety signals in the RCT evidence base. Steroid injections often look similarly tolerable in the short term, but reviews continue to discuss concerns about potential cartilage effects and systemic side-effects when steroids are used repeatedly—one reason many clinicians treat cortisone as an intermittent rescue rather than a frequent, long-term strategy. [ai4scholar:1c1e4d7c5fe9913fa21b2bc37f3cf2b8aaf8f271] [ai4scholar:d0609ea33cfaa93cc4e1994ecdc4db67cc0be741]

When might BMAC injections be an alternative to knee surgery?

A “cartilage defect” diagnosis in the knee (often described on an MRI as a contained “hole” or a full-thickness area of damage) sits in a different category from generalised osteoarthritis, and that difference matters when considering bone marrow aspirate concentrate (BMAC).

BMAC in plain terms

BMAC is made from a sample of a person’s own bone marrow—often taken with a needle from the pelvis (iliac crest)—which is then processed to concentrate a mixture of cells and signalling factors before being introduced to the knee. The aim is to support the body’s own repair response around a focal damaged area, rather than to act as a lubricant or an anti-inflammatory.

What the published evidence is (and is not)

Across the BMAC clinical literature, preparation methods and delivery strategies vary, and higher-quality comparative trials are still limited—so conclusions about the size and durability of benefit remain uncertain. Reviews also highlight uncertainty about standardised protocols and cost-effectiveness. [ai4scholar:e33a7af52c45c3877043b1022130e61fb1402c71]

Signals from specific BMAC-based techniques

One approach reported in clinical series is a single-stage repair where BMAC is embedded into a hyaluronic-acid–based scaffold, often combined with microfracture. In published series, patients (typically younger and active, with contained focal lesions) showed significant improvements across KOOS domains at midterm follow-up, with MRI appearances described as broadly acceptable for repair tissue—encouraging, but without a randomised comparison group. [ai4scholar:f4478d2297066878e856ec067e85c7c81afc95f3]

Other comparative signals come from studies where BMAC is used as an augmentation within a cartilage surgery pathway. For example, in a cohort of patients undergoing osteochondral autograft transplantation (OAT), a group treated with BMAC augmentation plus a structured rehabilitation protocol showed higher MOCART 2.0 MRI scores than comparison groups in that study design—suggesting BMAC may influence repair appearance in some settings, but not establishing clear superiority over other strategies across broader populations. [ai4scholar:19cba5f5923f33fa23f1329ce8c4b0ac8a345f67]

So, is BMAC “instead of surgery” realistic?

For some people with an isolated, well-defined defect who are trying to avoid a larger cartilage operation, an image-guided BMAC-based injection pathway may be part of the discussion—usually framed as a biologic support option with uncertain durability rather than a guaranteed substitute. For others, the better-supported role of BMAC in published pathways is as an adjunct used with a cartilage repair procedure, where the overall plan (including rehabilitation demands) can be as important as the biologic itself.

Who is a candidate for PRP hip injections under ultrasound?

PRP for hip osteoarthritis is generally discussed when symptoms remain intrusive despite a well-run conservative plan, but before the joint is truly end-stage. It is also worth being explicit that PRP use in the hip is typically off‑label and is not yet clearly set out in major hip osteoarthritis injection guidelines; the published evidence base is still smaller and more heterogeneous than for knee PRP.

In terms of candidacy, the profile most often represented in published comparative hip PRP studies is mild‑to‑moderate osteoarthritis rather than a fully “bone‑on‑bone” joint.

Where PRP sits relative to other injections in the hip remains uncertain, but a few comparative signals are available. In a 150‑patient observational study, PRP and hyaluronic acid both improved pain and function scores out to 12 months, with statistically greater improvements reported in the PRP group; the absolute differences were described as small, so “better” does not necessarily mean a dramatic change in day‑to‑day symptoms. [ai4scholar:3137323750352bd455e0f5e7c98fe39b68612ce8]

Separately, a 2025 systematic review and meta‑analysis (2 randomised trials and 1 cohort; 190 patients) found that adding hyaluronic acid to PRP (PRP+HA) did not improve results and was associated with worse pain scores at 3 and 12 months than PRP alone, with no meaningful functional advantage—so the current evidence base tends to favour standalone PRP where PRP is chosen. [ai4scholar:388d208499b60f3682a6868e135e8be2d095e0ea]

An outpatient PRP pathway in published hip series is typically structured around a same‑day appointment: blood draw, processing to prepare PRP, then image‑guided placement into the hip joint. The expected “shape” of response described in published studies is usually gradual (judged over weeks), with follow-up typically reported over months; the literature does not yet show whether PRP changes structural progression on imaging, so it is best viewed as a joint‑preservation adjunct rather than a cartilage‑restoration claim.

Deciding your next step and how LCC can help

Decisions about “what next” usually come down to what is being treated (diffuse arthritis vs a focal lesion) and what kind of time-horizon is realistic (days–weeks vs months). To keep this ending centred on those choices rather than any one provider, the emphasis here is a simple decision map and a few practical questions that can be used in any consultation.

A useful rule-of-thumb from the current evidence is that injections can reduce symptoms for a period but do not “cure” osteoarthritis. In the hip, hyaluronic acid trial results are mixed and on average modest in RCT syntheses, while PRP has emerging comparative evidence versus HA and limited meta-analytic data suggesting PRP+HA is not advantageous compared with PRP alone. [ai4scholar:3b87a6bc94e7f6921bff806987956248b15a73fb] [ai4scholar:44abbca81b747db54ea6cfa5a16a9e2057b91ece] [ai4scholar:3137323750352bd455e0f5e7c98fe39b68612ce8] [ai4scholar:388d208499b60f3682a6868e135e8be2d095e0ea]

In the knee, comparative trials and reviews often show steroid works faster early on, while PRP tends to last longer out to later follow-up in many (but not all) head-to-head studies. [ai4scholar:1c1e4d7c5fe9913fa21b2bc37f3cf2b8aaf8f271] [ai4scholar:1f198155781f789bb2dff67afebc2d728b8db570] [ai4scholar:d0609ea33cfaa93cc4e1994ecdc4db67cc0be741]

For BMAC, published reviews emphasize heterogeneity and the need for better trials, and current evidence includes case-series style reports and augmentation studies in surgical cartilage pathways. [ai4scholar:e33a7af52c45c3877043b1022130e61fb1402c71] [ai4scholar:f4478d2297066878e856ec067e85c7c81afc95f3] [ai4scholar:19cba5f5923f33fa23f1329ce8c4b0ac8a345f67]

Questions that often clarify the next step after a “tried physio, still symptomatic” plateau include:

• Is imaging (MRI/X-ray date noted on the report) pointing to widespread OA or a focal defect?
• Have strengthening and load-management been genuinely optimised over 8–12 weeks, rather than attempted briefly?
• Is the goal rapid flare control (days–weeks) or longer-lasting improvement (months)?
• How close is the discussion to joint replacement, and is it time for a surgical opinion because injections are unlikely to shift day-to-day function?
• What previous injections (drug/product and date) have been tried, and what was the size and duration of response?

In specialist cartilage practice, the sequence is typically: careful history (including night pain pattern), examination, review of imaging to separate diffuse arthritis from a treatable focal lesion, then an explicit discussion of evidence strength, likely duration, and trade-offs (including cost and the reality that some biologic options are not yet guideline-endorsed). In Harley Street, London Cartilage Clinic works within the MSK Doctors network and can offer ultrasound-guided injection pathways (including PRP, HA and BMAC where appropriate) alongside non-surgical and surgical joint-preservation opinions led by cartilage specialists such as Professor Paul Y. F. Lee.

For those who want a specialist opinion on where injections realistically sit between physiotherapy and surgery, consultations are available via londoncartilage.com—with the most helpful starting point being prior imaging reports and a dated list of treatments already tried.

1. [1] Intra-articular hyaluronic acid injections for hip osteoarthritis: a level I systematic review. (2025). https://doi.org/10.1007/s00590-025-04292-7 https://doi.org/10.1007/s00590-025-04292-7