Management of Bone Marrow Lesions of the Hip With Subchondral Calcium Phosphate Injection: Surgical Technique and Tips

Osteoporosis, Osteoarthritis, and Subchondral Insufficiency Fracture: Recent Insights

The increased incidence of osteoarthritis (OA), particularly knee and hip OA, and osteoporosis (OP), owing to population aging, have escalated the medical expense burden. Osteoarthritis is more prevalent in older women, and the involvement of subchondral bone fragility spotlights its association with OP. Notably, subchondral insufficiency fracture (SIF) may represent a more pronounced condition of OA pathophysiology. This review summarizes the relationship between OA and OP, incorporating recent insights into SIF. Progressive SIF leads to joint collapse and secondary OA and is associated with OP. Furthermore, the thinning and fragility of subchondral bone in early-stage OA suggest that SIF may be a subtype of OA (osteoporosis-related OA, OPOA) characterized by significant subchondral bone damage. The high bone mineral density observed in OA may be overestimated due to osteophytes and sclerosis and can potentially contribute to OPOA. The incidence of OPOA is expected to increase along with population aging. Therefore, prioritizing OP screening, early interventions for patients with early-stage OA, and fracture prevention measures such as rehabilitation, fracture liaison services, nutritional management, and medication guidance are essential.

Complications Following Intraosseous Injections of Calcium Phosphate Bone Cement in Subchondroplasty

An alternative approach to the major problem of osteoarthritis that has begun to pique the interest of researchers focuses on the pathology of the subchondral bone, its constant cross-talk with the articular cartilage, and its interaction with the joint. The presence of bone marrow lesions, detectable on MRI scans, has proven to be a cause of pain as well as a predictor of the progression of degenerative changes. Subchondroplasty is a relatively new surgical procedure for the treatment of these lesions, in which injectable calcium phosphate bone cement is infused into the affected area percutaneously, under fluoroscopic guidance. In its use as a synthetic scaffold, calcium phosphate bone cement exhibits considerable osteoconductivity, bioabsorbability, and low toxicity, thus showing great potential for restoring subchondral biomechanical properties through structural remodeling. Although published results appear quite promising, there are certain complications that the surgeon should be aware of. We reviewed the published data regarding complications of the procedure, highlighting possible causes according to these data, and suggesting safety measures. Avascular necrosis of the talus is the most reported concern. Postsurgical pain, infection, and continuous wound drainage due to bone substitute material extravasation to the joint or soft tissue are also mentioned, necessitating further standardization of the procedure. There are no reports of permanent postoperative disability or fatal outcomes.

Bone marrow edema of the hip: a narrative review

Bone marrow edema (BME) of the hip is a radiological-clinical condition with symptoms ranging from asymptomatic to severe, and it is characterized by increased interstitial fluid within the bone marrow, usually at the femur. Depending on the etiology it can be classified as primary or secondary. The primary cause of BME is unknown, while the secondary forms include traumatic, degenerative, inflammatory, vascular, infectious, metabolic, iatrogenic, and neoplastic etiologies. BME could be classified as reversible or progressive. Reversible forms include transient BME syndrome and regional migratory BME syndrome. Progressive forms include avascular necrosis of the femoral head (AVNH), subchondral insufficiency fracture, and hip degenerative arthritis. The diagnosis can be difficult, because at the beginning, the outbreak of hip pain, typically acute and disabling without any prior trauma or exceptional physical activity, is poorly supported by radiographic findings. MRI is the gold standard, and it shows an area of intermediate signal on T1-weighted MRI scans and a high signal on T2-weighted scans, usually lacking sharps margins. In the reversible form, BME is typically self-limiting, and it can be managed conservatively by means of pharmacological and physical therapy. Surgery is generally required for progressive forms in patients who failed non-operative treatment, and it ranges from femoral head and neck core decompression to total hip arthroplasty.

Subchondroplasty for Osteonecrosis of the Knee

Subchondroplasty is a relatively new minimally invasive procedure that has been used to treat bone marrow edema associated with osteoarthritis. Subchondroplasty as treatment for early stage osteonecrosis of the knee has not been extensively studied. The authors hypothesized that subchondroplasty may be an effective treatment for relieving pain, improving function, and preventing collapse in osteonecrosis. In this study, a retrospective review of 11 cases of subchondroplasty of the distal femur was conducted. There were no surgical complications with the procedure, and patients reported statistically significant improvement in pain and function. The mean Knee injury and Osteoarthritis Outcome Score for Joint Replacement improved from 44.3±4.9 preoperatively to 65.73±17.2 postoperatively. The mean visual analog scale score for knee pain was 7.8±1.18 preoperatively and 3.7±1.57 postoperatively. There has been one case of recurrence of osteonecrosis and no cases of joint collapse since the procedures occurred between 2018 and 2021. Previously, subchondroplasty for the treatment of osteonecrosis of the talus as well as of the knee joint showed positive results. This study affirms that subchondroplasty may also be a useful treatment option for relieving pain, improving function, and preventing joint collapse in osteonecrosis of the knee. [Orthopedics. 2023;46(5):e287-e290.].

Arthroscopic Approach to Preservation of the Hip with Avascular Necrosis

Avascular necrosis (AVN) of the hip is a devastating disease that affects middle-aged adults with poor outcomes if not treated in its early stages. In recent years, subchondroplasty with calcium phosphate solution has shown promising results. Concomitant intra-articular pathologies, including femoroacetabular impingement and chondral lesions, have been described in hips affected by AVN. These should be addressed at the time of surgery to lower the risk of failure. In this Technical Note, we describe an arthroscopic approach to femoral head subchondroplasty with precollapse lesion in AVN affected hip, combined with labral reconstruction and acetabular chondral treatment.