By Marc Darrow, MD, JD

Patients sometimes arrive with an X-ray described as “bone on bone” and the impression that hip replacement is the only remaining choice. Others have already tried physical therapy, medication, or injections and now struggle to walk. The right question is more specific: Is the hip joint the main source of pain, how advanced is the damage, and what outcome can each available treatment realistically provide?

On my September 12, 2026 radio program, a caller described severe right-hip pain, a cane, an apparent difference in leg length, two previous PRP injections, and a replacement already scheduled. I offered to examine him, but a radio conversation cannot establish whether the problem was osteoarthritis, femoral-head collapse, a contracture affecting leg position, a spine-related problem, or a combination. His report of pain around 9 or 10 out of 10 and difficulty bearing weight calls for prompt in-person evaluation and review of the actual imaging.

Does the pain really come from the hip joint?

Hip osteoarthritis commonly causes groin pain, stiffness, reduced internal rotation, and difficulty putting on shoes or walking. Pain around the buttock or outer hip may also involve the lumbar spine or gluteal tendons. An X-ray can show joint-space loss and bone changes, but the symptoms and examination must fit the image. Our related article, Before Hip Replacement: Is Your Pain Really Coming from the Hip Joint?, discusses these overlapping pain sources in detail.

An apparent leg-length difference can reflect a true difference in bone length, pelvic position, limited hip motion, or a combination. It should be measured and evaluated, especially before replacement. An ultrasound examination may identify surrounding tendons and guide an injection, but it cannot replace X-rays or MRI when the question is severe joint-space loss, osteonecrosis, or collapse of the femoral head.

What can be tried before an injection or replacement?

Depending on the diagnosis and prior care, treatment may include a tolerable strengthening and mobility program, a walking aid, weight management when relevant, and medication after a clinician reviews individual risks. The patient should understand the likely recovery and potential benefit of total hip replacement as well as its risks. When symptomatic moderate-to-severe osteoarthritis or advanced osteonecrosis has not responded to appropriate nonsurgical care, a patient who has chosen arthroplasty should not automatically be told to delay it for another injection. The ACR and AAHKS timing guideline addresses that specific situation. (1)

PRP: a blood product, not a stem-cell treatment

Platelet-rich plasma (PRP) is prepared from the patient’s blood. It contains concentrated platelets and is biologically distinct from a marrow or donor-cell preparation. Intra-articular PRP has been studied for hip osteoarthritis, but trials differ in the PRP formulation, comparison treatment, disease severity, and follow-up. A 2024 review of randomized studies did not establish that PRP rebuilds cartilage or predictably prevents replacement. (2)

Some patients may seek PRP for symptom relief when they still have useful motion and wish to continue conservative care. A limited response to previous injections, as in the caller’s account, should temper expectations for a repeat treatment. The goal and stopping point should be discussed beforehand.

Bone marrow aspirate concentrate for hip osteoarthritis

Bone marrow aspirate concentrate (BMAC) is collected from the patient’s pelvis and processed for injection. It contains a mixture of marrow cells and other components, including a small population of progenitor cells; it is not a vial of purified stem cells.

In our published case series, four patients with hip osteoarthritis received four BMAC injections and reported short-term improvements in pain and function. One woman with severe radiographic arthritis reported better function and had not undergone replacement at the last follow-up. These patient experiences are valuable to report accurately. The series had no comparison group, involved only four people, and had short follow-up; it cannot establish cartilage regrowth, a durable avoidance of replacement, or a success rate for other patients. (3)

A separate cohort of 19 patients with early hip or knee osteoarthritis reported satisfactory outcomes in 63.2%, while two went on to hip replacement within eight months. The combined knee-and-hip sample and absence of a control group limit conclusions about a particular hip patient’s prospects. (4)

A 2024 systematic review of hip BMAC studies found encouraging symptom and function reports but called for stronger, longer-term controlled trials. Another systematic review and single-arm meta-analysis noted the absence of randomized controlled trials among the hip studies it pooled. For now, an injection may be discussed as an investigational option in selected patients, with uncertainty about comparative benefit and long-term effects. (5) (6)

Osteonecrosis is a different diagnosis

Osteonecrosis, sometimes called avascular necrosis, involves injury to the blood supply of the femoral head. In an early, precollapse stage, a hip-preservation surgeon may discuss core decompression, sometimes combined with a bone marrow preparation. That is a procedure directed into the bone and is different from an injection into an arthritic joint. A 2025 review found possible improvements in pain and function when regenerative material was added to core decompression, while its effect on disease progression remained uncertain. (7)

Once the femoral head has collapsed and secondary arthritis is advanced, an injection cannot be assumed to restore its shape. The earlier stage, cause, lesion size, and extent of collapse matter. Animal experiments involving PRP and steroid-related osteonecrosis should not be used to promise prevention or reversal of osteonecrosis in people.

What about fat-derived and umbilical-cord products?

Adipose-derived preparations, cord blood, and Wharton’s-jelly products differ in source and processing. Their presence on a treatment menu does not establish that a particular vial contains viable stem cells or that it can rebuild an advanced hip joint. None is FDA-approved to treat hip osteoarthritis. Patients should ask what material is being used, what clinical evidence concerns that exact preparation and condition, and what regulatory pathway applies. (8)

When is replacement the more realistic option?

Severe, persistent joint pain, major loss of motion, progressive disability, and imaging showing collapse or advanced joint destruction make a surgical opinion especially important. Some patients with milder symptoms can reasonably continue conservative care. Others may wish to consider an injection after understanding its cost, risks, and uncertain benefit. A person who can barely bear weight should not assume an injection can safely replace prompt evaluation.

I want patients to have an honest decision, not a promise that one approach works for everyone. We review the pain source, structural damage, past response to treatment, medical risks, activity goals, and the likely consequences of waiting. That is how an injection and hip replacement can be compared for the individual in front of us.

References

  1. American College of Rheumatology and American Association of Hip and Knee Surgeons. Clinical practice guideline for the optimal timing of elective hip or knee arthroplasty for patients with symptomatic moderate-to-severe osteoarthritis or advanced symptomatic osteonecrosis. 2023. PMID: 37778918.
  2. Efficacy and Safety of Platelet-Rich Plasma Intra-articular Injections in Hip Osteoarthritis: A Systematic Review of Randomized Clinical Trials. 2024. PMID: 39569300.
  3. Darrow M, Shaw B, Darrow B, Wisz S. Short-Term Outcomes of Treatment of Hip Osteoarthritis With 4 Bone Marrow Concentrate Injections: A Case Series. Clinical Medicine Insights: Case Reports. 2018;11:1179547618791574.
  4. Rodriguez-Fontan F, Piuzzi NS, Kraeutler MJ, Pascual-Garrido C. Early Clinical Outcomes of Intra-Articular Injections of Bone Marrow Aspirate Concentrate for the Treatment of Early Osteoarthritis of the Hip and Knee: A Cohort Study. PM&R. 2018;10(12):1353–1359.
  5. Chandrashekar S, et al. Safety and Efficacy of Bone-Marrow Aspirate Concentrate in Hip Osteoarthritis: A Systematic Review of Current Clinical Evidence. Indian Journal of Orthopaedics. 2024;58:835–844.
  6. Clinical Response to Joint Infiltration With Bone Marrow Aspirate in Hip Osteoarthritis: A Systematic Review and Single-arm Meta-analysis. 2024. PMID: 39688823.
  7. The efficacy of core decompression combined with regenerative therapy in early femoral head necrosis: a systematic review and meta-analysis involving 954 subjects. 2025. PMID: 39840080.
  8. US Food and Drug Administration. Consumer Alert on Regenerative Medicine Products Including Stem Cells and Exosomes.