An Orthopaedic’s Guide to Subchondroplasty with Case Study

by Dr HC Chang | Jul 10, 2023 | Knee

What is Subchondroplasty?

Subchondroplasty is a minimally invasive surgical procedure used to treat certain types of bone defects in the joints, particularly in the subchondral region. The subchondral region refers to the layer of bone just beneath the cartilage in a joint.

During subchondroplasty, the surgeon uses imaging techniques such as fluoroscopy or intraoperative CT scanning to guide the procedure. A small incision is made near the affected joint, and a bone substitute material, often a calcium phosphate compound, is injected into the subchondral defect.

The purpose of subchondroplasty

The purpose of subchondroplasty is to stabilise and support the damaged or weakened bone in the subchondral area. This can help to alleviate pain, restore joint function, and potentially slow down the progression of joint degeneration.

The procedure is commonly used in the treatment of conditions such as bone marrow edema lesions, stress fractures, and other subchondral defects in the knee, ankle, hip, or other weight-bearing joints. It is often performed in combination with other joint preservation techniques, such as arthroscopy or cartilage repair procedures.

Subchondroplasty is considered a relatively new procedure, and its long-term outcomes are still being studied. It is important to consult with an orthopaedic specialist to determine if subchondroplasty is a suitable treatment option for your specific joint condition.

What Is a Bone Marrow Lesion BML?

In the context of subchondroplasty, a bone marrow lesion refers to an area of increased signal intensity or abnormality observed in the bone marrow on imaging studies such as MRI (Magnetic Resonance Imaging). These lesions are often associated with various joint conditions and can be a source of pain and functional impairment.

Bone marrow lesions are commonly found in individuals with osteoarthritis, a degenerative joint disease characterised by the breakdown of cartilage and changes in the underlying bone. They can also be present in other conditions such as bone contusions, stress fractures, avascular necrosis, and other forms of joint pathology.

These lesions typically appear as areas of increased signal intensity on MRI, indicating inflammation, edema, or changes in the bone structure. They are often found in the subchondral region, which is the layer of bone just beneath the joint cartilage.

Bone marrow lesions are thought to be associated with an imbalance between the load on the joint and the ability of the bone to withstand that load. The increased stress on the bone can lead to microfractures, bone remodelling, and the formation of these lesions.

Subchondroplasty aims to address bone marrow lesions by stabilising and reinforcing the weakened or damaged subchondral bone. By injecting a bone substitute material into the lesion site, the procedure is intended to provide support, promote healing, and potentially alleviate pain.

It’s important to note that the presence of a bone marrow lesion does not automatically indicate the need for subchondroplasty. The decision to undergo subchondroplasty or any other treatment approach should be made in consultation with a qualified orthopaedic specialist, who will assess the specific characteristics of the lesion and consider various factors to determine the most appropriate course of action.

When is Subchondroplasty Used to Treat Bone Marrow Lesions?

Subchondroplasty may be considered as a treatment option for a bone marrow lesion in certain cases where conservative measures have failed to provide relief or when the lesion is causing significant pain and functional impairment. The decision to proceed with subchondroplasty is typically made on a case-by-case basis, taking into account several factors. Here are some situations where subchondroplasty may be considered:

Persistent pain: If the bone marrow lesion is causing persistent and debilitating pain that significantly impacts daily activities and conservative treatments such as rest, physical therapy, pain medications, or injections have not provided sufficient relief, subchondroplasty may be considered.
Failure of conservative treatments: If conservative measures have been exhausted without satisfactory results, and the bone marrow lesion continues to cause pain and functional limitations, subchondroplasty may be explored as an alternative treatment.
Failure to respond to other interventions: If other interventions, such as arthroscopy or cartilage repair procedures, have been performed but have not adequately addressed the symptoms associated with the bone marrow lesion, subchondroplasty may be considered as an additional treatment option.
Lesion characteristics: The characteristics of the bone marrow lesion, including its size, location, and extent, will also influence the decision to perform subchondroplasty. Lesions that are well-defined, localised, and accessible may be more amenable to treatment with subchondroplasty.

It is important to note that subchondroplasty is not a universal solution for all bone marrow lesions. The appropriateness of the procedure will depend on various factors, including the underlying cause of the lesion, the individual’s overall health, and the specific characteristics of the lesion itself. A consultation with an orthopaedic specialist is necessary to assess the condition, discuss treatment options, and determine whether subchondroplasty is appropriate in a particular case.

Clinical Results of Subchondroplasty

There have been clinical studies and reports on the outcomes of subchondroplasty. However, it is important to note that research in this area is ongoing, and the long-term results and effectiveness of the procedure are still being evaluated. Here are some key findings from studies conducted on subchondroplasty:

Improvement in pain and function: Several studies have reported significant improvements in pain relief and functional outcomes following subchondroplasty. Patients have experienced reduced pain, improved joint function, and increased activity levels.
Reduction in bone marrow lesions: Subchondroplasty has shown the potential to reduce the size and severity of bone marrow lesions. Studies have demonstrated a decrease in the volume and intensity of lesions as observed on follow-up imaging.
Positive outcomes in specific joint conditions: Subchondroplasty has been studied in various joint conditions, such as knee osteoarthritis, bone marrow edema syndrome, and subchondral insufficiency fractures. Research has shown promising results in terms of pain reduction and functional improvement in these specific contexts.
Combination with other treatments: Subchondroplasty is often performed in combination with other joint preservation techniques, such as arthroscopy or cartilage repair procedures. Studies have explored the synergistic effects of these combined treatments and have reported improved outcomes compared to individual procedures alone.

It is worth noting that while these findings are encouraging, the success of subchondroplasty may vary depending on the individual patient, the specific joint condition, and other factors. Additionally, the long-term durability and efficacy of subchondroplasty are still being investigated, and further research is needed to fully understand its benefits and limitations.

Some Publications on Subchondroplasty

Nairn LN, Subramaniam M, Ekhtiari S, Axelrod DE, Grant JA, Khan M. Safety and early results of Subchondroplasty® for the treatment of bone marrow lesions in osteoarthritis: a systematic review. Knee Surg Sports Traumatol Arthrosc. 2021 Nov;29(11):3599-3607. doi: 10.1007/s00167-020-06294-w. Epub 2020 Sep 29. PMID: 32990774.

Conclusions: Existing low-quality studies show Subchondroplasty® to benefit patients with BMLs through reduction in pain and improvement in function, along with a high degree of satisfaction following the procedure. The low short-to-medium term conversion rate to arthroplasty suggests that Subchondroplasty® may play a role in delaying more invasive and expensive procedures in patients with BMLs. Subchondroplasty® is a novel procedure that has promising initial findings, but requires further high-quality, comparative studies with long-term follow-up to better understand the outcomes of the procedure and impact clinical practice recommendations.

Tran Y, Pelletier-Roy R, Merle G, Aubin CÉ, Nault ML. Subchondroplasty in the treatment of bone Marrow lesion in early Knee Osteoarthritis: A systematic review of clinical and radiological outcomes. Knee. 2022 Dec;39:279-290. doi: 10.1016/j.knee.2022.10.004. Epub 2022 Oct 27. PMID: 36332558.

Conclusions: Subchondroplasty is a promising avenue for the treatment of KOA. However, quality evidence is still required before any real conclusions and practical management guidelines can be drawn. Prospective, randomised studies with a control group and a rigorous assessment of long-term clinical and radiological outcomes are recommended

Chua K, Kang JYB, Ng FDJ, Pang HN, Lie DTT, Silva A, Chang PCC. Subchondroplasty for Bone Marrow Lesions in the Arthritic Knee Results in Pain Relief and Improvement in Function. J Knee Surg. 2021 May;34(6):665-671. doi: 10.1055/s-0039-1700568. Epub 2019 Nov 21. PMID: 31752023.

Abstract: Subchondroplasty is a relatively new joint preserving procedure, which involves the localised injection of calcium pyrophosphate bone substitute into the bone marrow lesion. The advent of magnetic resonance imaging (MRI) has greatly facilitated the identification of these bone marrow lesions. We investigated the clinical efficacy of subchondroplasty in the treatment of symptomatic bone marrow lesions in the knee, including knees with pre existing osteoarthritis. This study consisted of 12 patients whose knees were evaluated with standard radiographs and MRI to identify and localise the bone marrow lesions. They then underwent subchondroplasty under intraoperative radiographic guidance. Preoperative and postoperative visual analog scale (VAS) pain scores, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, and Knee Injury and Arthritis Outcome Scores (KOOS) were obtained. VAS scores improved significantly from 7.5 ± 1.8 before surgery to 5.2 ± 2.7 after surgery. This further improved to 2.1 ± 2.4 at the one-year follow-up. KOOS scores improved significantly from 38.5 ± 17.0 before surgery to 73.2 ± 19.0 at the one-year follow-up. WOMAC scores improved significantly from 47.8 ± 20.5 before surgery to 14.3 ± 13.2 at the one-year follow-up. Subchondroplasty offers an effective way to treat subchondral bone marrow lesions in the arthritic knee, resulting in improvement in symptoms and early return to activity. Long-term studies are required to evaluate if these benefits can last. This is a Level II study.

Case Study

A 53 year old man presented with recurrent left knee pain and swelling after running. The pain in his left knee will last from days to a week after each run.

Clinical examination showed tenderness of the posteromedial joint line as well as medial tibial plateau. His knee alignment was neutral.

MRI of his left knee showed a tear of the medial meniscus, a full-thickness cartilage lesion in the medial tibial plateau as well as a bone marrow lesion in the medial tibial plateau subchondral area underneath the area of cartilage loss.

He was treated conservatively with medications, rest and physiotherapy. However, the pain in his left knee would recur whenever he tried to return to running.

He eventually underwent left knee arthroscopic surgery to treat his knee pain.

During surgery, there was a complex tear involving the medial meniscus at the junction of the posterior third and middle body.

The medial meniscus tear was debrided to remove the torn and rough surface.

The meniscus tear was sandpapering down the articular cartilage of the medial tibial plateau resulting in a full thickness cartilage tear.

The torn medial tibial plateau cartilage was removed till a stable rim was present. The bone surface of the tibial plateau was exposed for cartilage repair.