Safety and Effectiveness of Talus Subchondroplasty and Bone Marrow Aspirate Concentrate for the Treatment of Osteochondral Defects of the Talus

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.

Needle Arthroscopic Subchondroplasty With Adipose-Derived Stem Cell Augmentation for the Treatment of Osteochondral Lesions of the Talus

Needle arthroscopy has enjoyed a tremendous growth concerning the quality of intraoperative images due to technical innovation, resulting in innovative possibilities concerning concomitant minimally invasive procedures and treatment of osteochondral lesions of the talus (OLT). These lesions have increasingly been receiving scientific attention in the orthopaedic (sports) medicine field, and, as such, the quality of evidence-based treatment for them has developed substantially. Treatment of OLTs-and specifically subchondroplasty. OLTs may also be suitable for needle arthroscopic interventions. The purpose of the present technical note is, therefore, to present an all-arthroscopic needle arthroscopic technique, including subchondroplasty with adipose-derived stem cells augmentation for osteochondral lesions of the talus.

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.].

What Factors are Associated With Conversion to Knee Arthroplasty After Subchondroplasty?

BACKGROUND

Subchondral bone marrow lesions identified on knee MRI are believed to play a role in osteoarthritis-associated pain. The subchondroplasty procedure is an arthroscopically assisted procedure for treating such lesions to avoid larger procedures such as knee arthroplasty. However, the survivorship free of conversion to arthroplasty and the factors associated with an increased likelihood of conversion of subchondroplasty to arthroplasty have not been well defined.

QUESTIONS/PURPOSES

We performed this study to (1) determine the 5-year survivorship of subchondroplasty free from conversion to knee arthroplasty (unicompartmental or total) and (2) identify variables that were associated with progression to knee arthroplasty after a subchondroplasty procedure.

METHODS

In all, 216 patients who underwent a subchondroplasty procedure performed by one surgeon with subchondroplasty experience at a single-center, multilocation facility between September 2014 and August 2017 were retrospectively evaluated to estimate survivorship free from conversion to knee arthroplasty at 5 years. The mean ± SD age and BMI at the time of subchondroplasty procedure were 59 ± 11 years and 33 ± 8 kg/m 2 , respectively; 60% (129 of 216) of the patients were women. Other variables collected were smoking status and grade and location of chondral lesions. The electronic medical record was reviewed to determine whether the patient had a knee arthroplasty after subchondroplasty. Survivorship free from conversion to knee arthroplasty at 5 years was calculated from a Kaplan-Meier survivorship estimator. Factors associated with progression to knee arthroplasty were examined using t-tests and chi-square analyses. Variables showing evidence of an association with knee arthroplasty were explored further using a Kaplan-Meier survivorship estimator (n = 190).

RESULTS

Kaplan-Meier survivorship free from conversion to knee arthroplasty was 73% (95% CI 67% to 79%) at 5 years after subchondroplasty. We found that age older than 50 years and Grade 4 chondral lesions were associated with conversion to knee arthroplasty. Patients with a Grade 4 chondral lesion had 5-year survivorship of 62% (95% CI 54% to 71%) and 59% (95% CI 50% to 69%) for those older than 50 years with a Grade 4 chondral lesion.

CONCLUSION

Currently, we recommend a detailed, informed discussion of the risks versus benefits with patients who are considering a subchondroplasty procedure, particularly patients aged 50 years and older and those with Grade 4 chondral lesions. Future randomized trials, including those that compare the subchondroplasty procedure with arthroscopy alone or nonoperative management options, are still needed to confirm the efficacy and role of the subchondroplasty procedure in patients with knee osteoarthritis, because only such prospective studies can determine the success of the procedure.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Bone Marrow Aspirate Concentrate Improves Outcomes in Adults With Osteochondral Dissecans of the Talus and Achilles Rupture

PURPOSE

The objective of this systematic literature review was to investigate the effects of the clinical application of bone marrow aspirate (BMA) and/or bone marrow aspirate concentrate (BMAC) in tendon and cartilage injuries in the foot and ankle.

METHODS

A search of the Embase, MEDLINE/PubMed, CINAHL, and Cochrane databases was performed in January 2021. The risk of bias of the studies was assessed using the tool "A Cochrane Risk of Bias Assessment Tool for Non-Randomized Studies." The outcomes analyzed included pain reduction and functional improvement with the use of BMA/BMAC in patients with tendon and cartilage injuries in the foot and ankle.

RESULTS

Eleven studies met the inclusion criteria for analysis, involving a total of 527 subjects with osteochondral lesions (OCLs) of the talus, cartilage lesions of the talus, and acute Achilles tendon rupture. BMAC was applied alone in 4 studies, and in 7 studies, it was compared with other techniques such as matrix-induced autologous chondrocyte implantation, particulate juvenile articular cartilage, or microfracture. Interventions demonstrated improved function and reduced foot and ankle pain and showed no serious adverse effects.

CONCLUSIONS

Evidence indicates that BMAC provides good clinical results, with improved function and reduced pain in adults with OCL and cartilage lesions of the talus and acute Achilles tendon rupture.

LEVEL OF EVIDENCE

Level IV, systematic review of level II to IV studies.

Mesenchymal stem cells for subchondral bone marrow lesions: From bench to bedside

Subchondral bone marrow lesions (BMLs) are areas of disease within subchondral bone that appear as T1 hypointense and T2 hyperintense ill-defined areas of bone marrow on magnetic resonance imaging. The most common bone marrow lesions include subchondral lesions related to osteoarthritis, osteochondral defects, and avascular necrosis. Emerging therapies include autologous biologic therapeutics, in particular mesenchymal stem cells (MSCs), to maintain and improve cartilage health; MSCs have become a potential treatment option for BMLs given the unmet need for disease modification. Active areas in the preclinical research of bone marrow lesions include the paracrine function of MSCs in pathways of angiogenesis and inflammation, and the use of bioactive scaffolds to optimize the environment for implanted MSCs by facilitating chondrogenesis and higher bone volumes. A review of the clinical data demonstrates improvements in pain and functional outcomes when patients with knee osteoarthritis were treated with MSCs, suggesting that BM-MSCs can be a safe and effective treatment for patients with painful knee osteoarthritis with or without bone marrow lesions. Preliminary data examining MSCs in osteochondral defects suggest they can be beneficial as a subchondral injection alone, or as a surgical augmentation. In patients with hip avascular necrosis, those with earlier stage disease have improved outcomes when core decompression is augmented with MSCs, whereas patients in later stages post-collapse have equivalent outcomes with or without MSC treatment. While the evidence for the use of MSCs in conditions with associated bone marrow lesions seems promising, there remains a need for continued investigation into this treatment as a viable treatment option.

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Common BMLs include osteoarthritis, osteochondral defects, and avascular necrosis.

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Patients with knee osteoarthritis treated with MSCs show improved pain and function.

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MSCs used as subchondral injection or surgical augmentation in osteochondral defects

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Improved outcomes of early hip avascular necrosis after core decompression with MSCs

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Additional preclinical and clinical evidence of MSCs as treatment for BMLs is needed.

Avascular Necrosis of the Talus Following Subchondroplasty: A Case Report and Review of Literature

CASE

Avascular necrosis (AVN) of the talus in a 45-year-old female following subchondroplasty with calcium phosphate bone filler for treatment of anterolateral and posteromedial talar dome bone marrow lesions (BMLs). The patient subsequently presented as consultation, 18 months postoperatively, with AVN of the talus. After failing conservative management, the patient underwent a total ankle arthroplasty at 46 months after subchondroplasty with resolution of pain.

CONCLUSION

There are few studies that have reported on the safety of subchondroplasty of the talus. Given the tenuous blood supply to the talar body and poor patient outcomes associated with AVN, caution should be taken before extrapolating the generally positive results of subchondroplasty in the knee.

LEVEL OF EVIDENCE

Level IV.

Safety and early results of Subchondroplasty® for the treatment of bone marrow lesions in osteoarthritis: a systematic review

PURPOSE

Subchondroplasty® is a novel minimally invasive procedure for painful subchondral bone marrow lesions (BMLs). The aim of this systematic review was to characterize the clinical outcomes of the Subchondroplasty® procedure, a novel minimally invasive procedure for the treatment of BMLs. The hypothesis tested was that patients experience improvements in pain and functional outcomes following the Subchondroplasty® procedure.

METHODS

MEDLINE, Embase, Web of Science, and Clinicaltrials.gov were searched from database inception to search date (June 10, 2020) for all clinical studies which discussed Subchondroplasty®. Two reviewers independently screened 45 unique results and 17 studies were included in the final analysis. Data were collected regarding patient demographics, indications, pain, functional scores, conversion to TKA, and complications of the procedure.

RESULTS

All but one study were level IV evidence; the mean MINORS score was 9 ± 2. There were 756 patients included, 45.1% were female, and the mean age was 54 years (range 20-85). Thirteen studies investigated the effect Subchondroplasty® to the knee, while four studied the impact on the foot and ankle. Median length of follow-up was 12 months. The most common indication for Subchondroplasty® was joint pain with corresponding BML. Major contraindications to Subchondroplasty® included severe OA, joint instability, and malalignment. Mean pain score on visual analogue scale (VAS) prior to Subchondroplasty® was 7.8 ± 0.6, but decreased to 3.4 ± 0.7 postoperatively. All studies investigating functional scores reported improvement following Subchondroplasty® (IKDC 31.7 ± 1.9-54.0 ± 4.2 and KOOS 38.1 ± 0.6-70.0 ± 4.1). There were consistently high levels of patient satisfaction; 87 ± 8% of patients would be willing to undergo the procedure again. Seven cases of complications were reported, most seriously osteomyelitis and avascular necrosis. Conversion to knee arthroplasty ranged from 12.5 to 30% with length of follow-up ranging from 10 months to 7 years.

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.

LEVEL OF EVIDENCE

Systematic Review of Level III and IV Studies, Level IV.

Avascular Necrosis of the Talus After Subchondroplasty

BACKGROUND

Subchondroplasty (SCP) is a relatively new procedure, developed in 2007 for the treatment of bone marrow lesions (BMLs), that has shown promising results in the knee through several different case series. The foot and ankle literature, however, is sparse, with only a few documented case reports or case series. At our institution, we have identified several patients with complications after this specific procedure. As a result, we report our case series of patients who developed talar avascular necrosis (AVN) after undergoing SCP.

METHODS

A retrospective review was performed of patients who underwent SCP for a talar BML at our facility or who were referred to our facility after undergoing SCP at an outside institution. Patients were included if they developed radiographic evidence of talar AVN after the procedure. Patient demographics, comorbidities, concomitant intraoperative procedures, complications, and subsequent interventions were reviewed.

RESULTS

Seven patients were identified as having radiographic evidence of talar AVN after SCP. Average time interval was 23 months postoperative from index procedure to radiographic confirmation of AVN. Two of the index procedures were performed at our institution, whereas 5 of the index procedures were performed at outside institutions and referred for further management. Three patients had documented risk factors for AVN before the SCP procedure. All 7 patients were symptomatic from the AVN.

CONCLUSION

We identified 7 patients who went on to develop talar AVN after having undergone SCP.

LEVEL OF EVIDENCE

Level IV, case series.

Subchondroplasty of the Ankle and Hindfoot for Treatment of Osteochondral Lesions and Stress Fractures: Initial Imaging Experience

Objective:To describe the imaging findings of patients treated with subchondroplasty (SCP) of the ankle and hindfoot. Materials and Methods: Eighteen patients (10 men, 8 women; age mean 43.1 years [range 20.1-67.7 years]) underwent ankle and hindfoot SCP at a single center over a 14-month period. Imaging data were reviewed retrospectively by 2 radiologists by consensus interpretation, including preoperative radiography (18), computed tomography (CT) (11), and magnetic resonance imaging (MRI) (13) and postoperative radiography (10), CT (4), and MRI (6). Follow-up imaging was acquired 1 month to 1.6 years following SCP. Results: Indications for SCP included symptomatic bone marrow lesions (BMLs) secondary to an osteochondral lesion (OCL) (16/18) or stress fracture (2/18). While focal radiodensity related to the SCP procedure was retrospectively identifiable on postoperative radiography in all except 1 case (10/11), postprocedural findings were not described by the interpreting radiologist in 6/11 cases. On CT, the average injected synthetic calcium phosphate (CaP) volume was 1.15 cm³ (SD = 0.33 cm³); mean CT attenuation of the injectate was 1220 HU (range 1058-1465 HU). In all patients who had pre- and postoperative MRI (5/18), BML size decreased on follow-up MRI. Extra-osseous extrusion of CaP was not seen on postoperative radiography, CT, or MRI. Conclusion: Physicians should be aware of the expanding preoperative indications and postoperative imaging findings of SCP, which is being performed with increasing frequency in the ankle and hindfoot.Levels of Evidence: Diagnostic, Level III: Retrospective cohort study.

Talar Avascular Necrosis After Calcium Phosphate Injection Treatment of Talar Bone Marrow Lesions: A Report of 2 Cases

CASE

We report on 2 patients who developed avascular necrosis (AVN) of the talus and poor patient outcomes after undergoing calcium phosphate injection into talar dome bone marrow lesions.

CONCLUSION

Subchondroplasty, defined as calcium phosphate injection for the treatment of articular bone marrow edema, is a recently described procedure for use in the ankle joint. In our opinion, the limited available research is of poor quality and describes equivocal improvement in patient symptoms after this procedure. Given the debilitating outcomes and extensive AVN we observed in 2 patients, we strongly advise caution in the use of this procedure in the talus.

Emerging Options for Biologic Enhancement of Stress Fracture Healing in Athletes

In an era of continual single-sport specialization and year-round training, overuse injuries, including stress injuries of bone, are increasingly common. These injuries can be season- or even career-ending. For many elite and professional athletes, the traditional treatment strategy of immobilization and extended rest from sports participation is often not practical or acceptable. An understanding of modern strategies for evaluating and treating stress fractures is paramount for maintaining athletic participation and optimal athletic performance. This begins with the ability to categorize and stratify bony stress injuries by both severity and risk of fracture progression. Surgical procedures such as open reduction and internal fixation or intramedullary fixation with possible bone grafting remain the standard of care for chronic or severe stress fractures. However, emerging techniques to augment the biologic environment are a minimally invasive adjunct for stimulating and supporting bone healing in elite-level athletes to optimize bone health, expedite recovery, and decrease the risk of nonunion or catastrophic fracture.

Talar Osteonecrosis After Subchondroplasty for Acute Lateral Ligament Injuries: Case Series

Talar osteonecrosis is a well-described phenomenon following talar neck fracture, but is a rarely described complication after procedures about the foot and ankle. Here we describe the clinical course of 5 cases of talar osteonecrosis following injection of calcium phosphate into the talus (subchondroplasty) with or without acute lateral ligament repair after acute lateral ankle ligament injuries performed at an outside institution. Practitioners should be aware of this potentially devastating complication. Future research is indicated to determine the safety and efficacy of subchondroplasty for the talus.