While there are several types of arthritis that can affect the hip, osteoarthritis (OA) is degenerative and occurs when the protective cartilage that cushions the end of the bones wears down with time.
Hip osteoarthritis, is one the most common joint disorders in the United States. Based on population studies, 19.6% of people over the age of 50 have radiographic evidence of hip OA and 4.2% have symptomatic disease (Kim et al, 2014).
Several risk factors may contribute to the development of hip OA, including:
Systemic risk factors (eg, age, gender, genetics)
Intrinsic joint risk factors (eg, anatomic variants and joint laxity)
Extrinsic risk factors (eg, repetitive physical activities and obesity)
Population studies suggest that hip OA is twice as common in women as in men, and there is evidence to suggest a strong genetic component (Aresti et al, 2016), however, to date the exact primary hip OA etiology remains unknown (Lespasio et al, 2018).
The degenerative process in osteoarthritis effects the entire joint, and involves a progressive loss of articular cartilage, subchondral cystic formation, osteophyte or bone spur formation, periarticular ligamentous laxity, muscle weakness, and possible synovial inflammation (Hutton et al, 1989).
WHAT ARE THE SYMPTOMS OF HIP OSTEOARTHRITIS?
As the cartilage cushion wears down the cartilage becomes rough, and patients may experience clicking and decreased range of motion.
HOW IS HIP ARTHRITIS DIAGNOSED?
The diagnosis of hip osteoarthritis is based on a detailed history, physical examination, and imaging.
Plain radiographs or x-rays are the most common modality to diagnose hip osteoarthritis, and can show features of cartilage damage including narrowing of the joint, bone cysts and bone spurs (osteophytes) (Aresti et al, 2016; Karachalios et al, 2007). However, there is a difference between clinical symptoms of arthritis and radiographic findings of arthritis.
Only 21% of patient with hip osteoarthritis experience pain. With such a high risk of incidental radiographic findings, patients may undergo unnecessary treatments that will not improve their symptoms, an accurate diagnosis is important to guide treatment decisions (Kim et al, 2015).
Hip pain from osteoarthritis can be confused with other common hip conditions, including greater trochanteric pain syndrome, piriformis syndrome, adductor tendon pain, stress fracture, inflammatory arthropathies (eg, rheumatoid arthritis), lumbar radiculopathy, pelvis bone tumors, osteonecrosis, pelvic insufficiency fractures, and meralgia parasthetica. Nonmusculoskeletal conditions (eg, groin hernia, intrapelvic pathology, and leaking abdominal aortic aneurysms) may also present with hip and/or groin pain.
Maintaining a healthy body weight, avoiding overuse or repetitive activities, and strength training around the joint can help manage pain. It is important to stay as active as possible, and keep the muscles from getting weak. Braces, medications and injections can also help control pain (Quinn et al, 2018; Zhang et al, 2008).
Hyaluronic
acid is a naturally occurring compound in the joint, and may help
protect the cartilage and help control pain associated with hip
osteoarthritis. Hyaluronic acid down-regulates pro-inflammatory cytokines, such as interleukin-1 (IL-1), impacting pain relief and immune modulation. Some studies conducted in vitro and in vivo on humans, shows hyaluronic acid also seems to have a chondroprotective effect (Takahashi et al, 2000).
At this time, the US Food and Drug Administration (FDA)
has approved viscosupplementation injections for knee osteoarthritis
only. The FDA has not approved viscosupplementation for the
hip and guidelines from the European and international scientific societies for the management of hip osteoarthritis differ regarding recommendations of intra-articular hyaluronic acid for hip osteoarthritis (Ronconi et al, 2023). In the US, the use in hip osteoarthritis is considered off-label.
PRP therapy concentrates the growth factors in your own blood. A recent systematic review of 5 randomized controlled studies found PRP for hip osteoarthritis significantly reduced pain and improved function without any major adverse events (Almutairi and Alazzeh, 2024).
In a randomized controlled study comparing the efficacy of autologous PRP, hyaluronic acid, or a combination of both PRP and hyaluronic acid in 111 patients at all follow-up intervals up to 12-month the PRP group showed a significant improvement when compared to the other groups. The combination of PRP and hyaluronic acid did not offer any greater improvement in pain (Dallari et al, 2016).
In a randomized controlled study of 43 patients with severe hip osteoarthritis treated with either PRP or hyaluronic acid, the PRP injection had short term benefit, but the hyaluronic acid had greater longer term improvement in pain and function at the 16-week follow up (Di Sante et al, 2016).
In a randomized controlled trial comparing PRP and hyaluronic acid 74 patients were included and PRP showed improved function and reduced pain up to 12-months after the injection (Villanova-Lopez et al, 2020).
In another randomized controlled study comparing PRP, hyaluronic acid, or a combination of both injections in 105 patients followed for 6-months the PRP and combination group showed greater improvement in pain than the hyaluronic acid group. The combination of PRP and hyaluronic acid also did not offer any greater improvement in pain than the PRP alone group (Nouri et al, 2022).
Bone
marrow concentrate injections use mesenchymal stem cells (MSCs), a cell type
found in bone marrow, to improve pain and function in hip
osteoarthritis. Mesenchymal stem cells have been shown to be capable of
cartilage and bone repair in animal models and early human clinical
trials (Pittenger et al, 1999; Lang et al, 2013; Centeno et al, 2008). Contemporary literature suggests that the "regenerative effects" of MSCs are mediated by secreted factors, however, the role of mesenchymal stem cells and their role in musculoskeletal repair is still unclear (Diekman et al, 2010; Indrawattana et al, 2004).
Case studies and registry data have demonstrated encouraging results in hip osteoarthritis with no significant complications reported (Centeno et al, 2014; Whitney et al, 2020).
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