One step treatment of talus osteochondral lesions with microfracture and cell free hyaluronic acid based scaffold combination

The efficacy of autologous matrix-induced chondrogenesis (AMIC) for osteochondral lesions of the talus in the mid-long term: a systematic review and meta-analysis

PURPOSE

The objective of this study was to provide a comprehensive review of the existing literature regarding the treatment of osteochondral lesions of the talus (OLT) using autologous matrix-induced chondrogenesis (AMIC), while also discussing the mid-long term functional outcomes, complications, and surgical failure rate.

METHODS

We searched Embase, PubMed, and Web of Science for studies on OLT treated with AMIC with an average follow-up of at least 2 years. Publication information, patient data, functional scores, surgical failure rate, and complications were extracted.

RESULTS

A total of 15 studies were screened and included, with 12 case series selected for meta-analysis and 3 non-randomized controlled studies chosen for descriptive analysis. The improvements in the Visual Analog Scale (VAS), the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot, and Tegner scores at the last follow-up were (SMD = - 2.825, 95% CI - 3.343 to  - 2.306, P < 0.001), (SMD = 2.73, 95% CI 1.60 to 3.86, P < 0.001), (SMD = 0.85, 95% CI 0.5 to 1.2, P < 0.001) respectively compared to preoperative values. The surgery failure rate was 11% (95% CI 8-15%), with a total of 12 patients experiencing complications.

CONCLUSION

The use of AMIC demonstrates a positive impact on pain management, functional improvement, and mobility enhancement in patients with OLT. It is worth noting that the choice of stent for AMIC, patient age, and OLT size can influence the ultimate clinical outcomes. This study provides evidences supporting the safety and efficacy of AMIC as a viable treatment option in real-world medical practice.

Revision of Failed Osteochondritis dissecans Surgical Treatment: Case Report

BACKGROUND

Osteochondritis dissecans (OD) is one of the most common cartilage lesions of the knee. Conservative treatment is recommended if the lesions are stable with no loose bodies or there are open physes. Surgical intervention is recommended as the primary treatment in symptomatic adults with unstable chondral lesions or with concomitant loose bodies.

METHODS

We describe a case of a patient suffering from OD with a bone lesion in the weight-bearing area of medial femoral condyle. Arthroscopy was performed and an osteochondral fragment from the medial femoral condyle was observed and two articular loose bodies were removed. After months, the patient returned with pain and a locked knee. magnetic resonance imaging (MRI) presented a new unstable chondral flap at the posterior border of the previous lesion. Surgery was performed again, and at open examination, the previous OD lesions were covered by regenerative tissue, with a lesion of 3 cm2 at the inferior medial part of the chondral flap. The peripheral margins were cleaned, and a subchondral crater was curetted. The subchondral lesion was debrided, and the flap was fixed with pins and a central bioresorbable screws.

RESULTS

Revision surgery with fixation of the chondral flap using bioresorbable pins and screws led to satisfactory results.

CONCLUSION

Open revision surgery allowed us a more accurate assessment of the OD area to provide an effective fixation of the chondral flap and in this circumstance, this should have been done after seeing the first MRI.

Operative management of osteochondral lesions of the talus: 2024 recommendations of the working group 'clinical tissue regeneration' of the German Society of Orthopedics and Traumatology (DGOU)

The working group 'Clinical Tissue Regeneration' of the German Society of Orthopedics and Traumatology (DGOU) issues this paper with updating its guidelines. Literature was analyzed regarding different topics relevant to osteochondral lesions of the talus (OLT) treatment. This process concluded with a statement for each topic reflecting the best scientific evidence available with a grade of recommendation. All group members rated the statements to identify possible gaps between literature and current clinical practice. Fixation of a vital bony fragment should be considered in large fragments. In children with open physis, retrograde drilling seems to work better than in adults, but even there, the revision rate reaches 50%. The literature supports debridement with bone marrow stimulation (BMS) in lesions smaller than 1.0 cm² without bony defect. The additional use of a scaffold can be recommended in lesions larger than 1.0 cm². For other scaffolds besides AMIC®/Chondro-Gide®, there is only limited evidence. Systematic reviews report good to excellent clinical results in 87% of the patients after osteochondral transplantation (OCT), but donor site morbidity is of concern, reaching 16.9%. There is no evidence of any additional benefit from autologous chondrocyte implantation (ACI). Minced cartilage lacks any supporting data. Metallic resurfacing of OLT can only be recommended as a second-line treatment. A medial malleolar osteotomy has a minor effect on the clinical outcome compared to the many other factors influencing the clinical result.

3D printed osteochondral scaffolds: design strategies, present applications and future perspectives

Articular osteochondral (OC) defects are a global clinical problem characterized by loss of full-thickness articular cartilage with underlying calcified cartilage through to the subchondral bone. While current surgical treatments can relieve pain, none of them can completely repair all components of the OC unit and restore its original function. With the rapid development of three-dimensional (3D) printing technology, admirable progress has been made in bone and cartilage reconstruction, providing new strategies for restoring joint function. 3D printing has the advantages of fast speed, high precision, and personalized customization to meet the requirements of irregular geometry, differentiated composition, and multi-layered boundary layer structures of joint OC scaffolds. This review captures the original published researches on the application of 3D printing technology to the repair of entire OC units and provides a comprehensive summary of the recent advances in 3D printed OC scaffolds. We first introduce the gradient structure and biological properties of articular OC tissue. The considerations for the development of 3D printed OC scaffolds are emphatically summarized, including material types, fabrication techniques, structural design and seed cells. Especially from the perspective of material composition and structural design, the classification, characteristics and latest research progress of discrete gradient scaffolds (biphasic, triphasic and multiphasic scaffolds) and continuous gradient scaffolds (gradient material and/or structure, and gradient interface) are summarized. Finally, we also describe the important progress and application prospect of 3D printing technology in OC interface regeneration. 3D printing technology for OC reconstruction should simulate the gradient structure of subchondral bone and cartilage. Therefore, we must not only strengthen the basic research on OC structure, but also continue to explore the role of 3D printing technology in OC tissue engineering. This will enable better structural and functional bionics of OC scaffolds, ultimately improving the repair of OC defects.

Advances in Cartilage Repair

Osteochondral lesions of the ankle joint are typically associated with a traumatic etiology and present with ankle pain and swelling. Conservative management yields unsatisfactory results because of the poor healing capacity of the articular cartilage. Smaller lesions (<100 mm² or <10 mm) can be treated with less invasive procedures such as arthroscopic debridement, anterograde drilling, scaffold-based therapies, and augmentation with biological adjuvants. For patients with large lesions (>100 mm² or >10 mm), cystic lesions, uncontained lesions, or patients who have failed prior bone marrow stimulation, management with autologous osteochondral transplantation is indicated.

Comparison of arthroscopic debridement and microfracture in the treatment of osteochondral lesion of talus

Objective

This study was performed to compare the clinical effect of arthroscopic debridement vs. arthroscopic microfracture in the treatment of osteochondral lesions of the talus.

Methods

We retrospectively reviewed patients with osteochondral lesion of talus who were admitted to our hospital from April 2020 to April 2021. The patients were divided into Group A (arthroscopic debridement group, n = 39) and Group B (arthroscopic microfracture group, n = 42), and the intraoperative details in the two groups were analyzed. The American Orthopaedic Foot and Ankle Society (AOFAS) score and visual analogue scale (VAS) score were compared between the two groups before surgery and at the last follow-up.

Results

The postoperative AOFAS score (Group A, 40.9-82.26; Group B, 38.12-87.38), VAS score (Group A, 6.44-3.92; Group B, 6.38-2.05) significantly improved in both groups, but the improvement was significantly greater in Group B than in Group A (P < 0.05). Among all patients, the AOFAS and VAS scores of men aged ≤30 years and patients with a low body mass index (BMI) improved more significantly (P < 0.05).

Conclusion

The arthroscopic microfracture for the treatment of osteochondral lesion of talus is superior to joint debridement in terms of improving ankle function, especially in relatively young men with a relatively low BMI.

Prognostic factors for the management of chondral defects of the knee and ankle joint: a systematic review

Purpose

Different surgical techniques to manage cartilage defects are available, including microfracture (MFx), autologous chondrocyte implantation (ACI), osteoarticular auto- or allograft transplantation (OAT), autologous matrix-induced chondrogenesis (AMIC). This study investigated the patient-related prognostic factors on the clinical outcomes of surgically treated knee and ankle cartilage defects.

Methods

This study followed the PRISMA statement. In May 2022, the following databases were accessed: PubMed, Google Scholar, Embase, and Scopus. All the studies investigating the outcomes of surgical management for knee and/or talus chondral defects were accessed. Only studies performing mesenchymal stem cells transplantation, OAT, MFx, ACI, and AMIC were considered. A multiple linear model regression analysis through the Pearson Product–Moment Correlation Coefficient was used.

Results

Data from 184 articles (8905 procedures) were retrieved. Female sex showed a positive moderate association with visual analogue scale at last follow-up (P = 0.02). Patient age had a negative association with the American Orthopaedic Foot and Ankle Score (P = 0.04) and Lysholm Knee Scoring Scale (P = 0.03). BMI was strongly associated with graft hypertrophy (P = 0.01). Greater values of VAS at baseline negatively correlate with lower values of Tegner Activity Scale at last follow-up (P < 0.0001).

Conclusion

The clinical outcomes were mostly related to the patients’ performance status prior surgery. A greater BMI was associated with greater rate of hypertrophy. Female sex and older age evidenced fair influence, while symptom duration prior to the surgical intervention and cartilage defect size evidenced no association with the surgical outcome. Lesion size and symptom duration did not evidence any association with the surgical outcome.

Autologous Matrix-Induced Chondrogenesis (AMIC) for Osteochondral Defects of the Talus: A Systematic Review

Autologous matrix-induced chondrogenesis (AMIC) has been advocated for the management of talar osteochondral lesions (OCLs). This systematic review, which was conducted according to the PRISMA 2020 guidelines, investigated the clinical and imaging efficacy and safety of the AMIC technique in the management of OCLs of the talus. Only studies investigating AMIC for talar chondral defects that were published in peer-reviewed journals were considered. In September 2022, the following databases were accessed: PubMed, Web of Science, Google Scholar, and Embase. Data on the visual analogue scale (VAS), American Orthopaedic Foot and Ankle Score (AOFAS), Tegner activity scale, and Foot Function Index (FFI) were retrieved. To evaluate the morphological MRI findings, data obtained from the magnetic resonance observation of cartilage repair tissue (MOCART) scores were evaluated. Data on hypertrophy, failures, and revision surgeries were also collected. Data from 778 patients (39% women, 61% men) were collected. The mean length of the follow-up was 37.4 ± 16.1 months. The mean age of the patients was 36.4 ± 5.1 years, and the mean BMI was 26.1 ± 1.6 kg/m2. The mean defect size was 2.1 ± 1.9 cm2. Following the AMIC technique, patients demonstrated an improved VAS (p < 0.001), AOFAS (p < 0.001), and FFI (p = 0.02) score. The MOCART score also improved from the baseline (p = 0.03). No difference was observed in the Tegner score (p = 0.08). No graft delamination and hypertrophy were reported in 353 patients. 7.8% (44 of 564) of patients required revision surgeries, and 6.2% (32 of 515) of patients were considered failures. The AMIC technique could be effective in improving symptoms and the function of chondral defects of the talus.

Hyaluronic acid as an adjunct to microfracture in the treatment of osteochondral lesions of the talus: a systematic review of randomized controlled trials

BACKGROUND

Osteochondral lesions of the talus (OLT) are common after ankle trauma. Studies have shown that bioactive substances, such as hyaluronic acid (HA), alone, or in combination, with surgical treatment could improve cartilage regeneration and repair, but the effect of HA on patient reported outcomes is unclear.

METHODS

Literature searches were performed across four databases (PubMed, SPORTDiscus, Scopus, and The Cochrane Library) for randomized controlled trials in which at least one treatment arm involved use of HA as an adjunct to microfracture to treat patients with OLT. Primary outcomes included the American Orthopaedic Foot and Ankle Society scores (AOFAS), and the Visual Analog Scale (VAS) for pain. The level of evidence and methodological quality were evaluated using the Modified Coleman Methodology Score (MCMS).

RESULTS

Three randomized studies were eligible for review with a total of 132 patients (35, 40, 57 patients, respectively) and follow-up ranged from 10.5 to 25 months. Utilization of HA at the time of microfracture resulted in greater improvement in AOFAS scores compared to microfracture alone. The pooled effect size was moderate (Standardized Mean Difference [SMD] 0.45, 95% Confidence Interval [CI] 0.06, 0.84; P = .02) and between-study heterogeneity was low (I-squared = 0%). Utilization of HA during microfracture also led to greater improvement in VAS-pain scores compared to microfracture alone. The pooled effect size was very large (SMD -3.86, 95% CI -4.75, - 2.97; P < .001) and heterogeneity was moderate (I-squared = 69%).

CONCLUSION

Hyaluronic acid injection as an adjunct to arthroscopic MF in OLT provides clinically important improvements in function and pain at short-term follow-up compared to MF alone. Future longer-term follow-up studies are warranted to investigate the durability of MF with HA for treatment of OLT.

3D Printing for Bone-Cartilage Interface Regeneration

Due to the vasculature defects and/or the avascular nature of cartilage, as well as the complex gradients for bone-cartilage interface regeneration and the layered zonal architecture, self-repair of cartilage and subchondral bone is challenging. Currently, the primary osteochondral defect treatment strategies, including artificial joint replacement and autologous and allogeneic bone graft, are limited by their ability to simply repair, rather than induce regeneration of tissues. Meanwhile, over the past two decades, three-dimension (3D) printing technology has achieved admirable advancements in bone and cartilage reconstruction, providing a new strategy for restoring joint function. The advantages of 3D printing hybrid materials include rapid and accurate molding, as well as personalized therapy. However, certain challenges also exist. For instance, 3D printing technology for osteochondral reconstruction must simulate the histological structure of cartilage and subchondral bone, thus, it is necessary to determine the optimal bioink concentrations to maintain mechanical strength and cell viability, while also identifying biomaterials with dual bioactivities capable of simultaneously regenerating cartilage. The study showed that the regeneration of bone-cartilage interface is crucial for the repair of osteochondral defect. In this review, we focus on the significant progress and application of 3D printing technology for bone-cartilage interface regeneration, while also expounding the potential prospects for 3D printing technology and highlighting some of the most significant challenges currently facing this field.

Osteochondral Injury of the Talus Treated With Cell-Free Hyaluronic Acid-Based Scaffold (Hyalofast®) - A Reliable Solution

Background: Osteochondral injuries commonly occur in load-bearing joints, mainly caused by traumatic incidents that can lead to detachment of the cartilage fragment either partial or complete.

Objective: This study aims to review the long-term outcome of osteochondral injury of the talus treated with a cell-free hyaluronic acid-based scaffold (Hyalofast®, Anika Therapeutics Inc., Bedford, Massachusetts, USA).

Method: This study evaluated the data of seven patients who underwent medial malleolus osteotomy, microfracture, and cell-free hyaluronic acid-based scaffold (HYALOFAST®) insertion between 2015 to 2018. All patients had an osteochondral lesion (OCL) grade III and IV of the talus based on Dipaola classification due to trauma. They were followed up for at least two years and assessed by the short form 36 health survey questionnaire (SF36) for both physical functioning and mental health, American Orthopaedic Foot and Ankle Society (AOFAS) scoring system, and visual analog scale (VAS).

Result: All patients were satisfied in terms of physical function, mental health, and pain after one month of surgery (p-value<0.05). There was also an improvement in AOFAS hindfoot and VAS scores from preoperative to postoperative. No complications were noted in the surgical site or bone union.

Conclusion: Medial malleolus osteotomy, cell-free hyaluronic acid-based scaffold (HYALOFAST®) grafting, and microfracture are considered relatively easy techniques that are a good choice for patients with sizeable cartilage deficiency and provide a good functional outcome.

Arthroscopic one-step matrix-assisted bone marrow stimulation for the treatment of osteochondral defects of the talus

OBJECTIVE

All arthroscopic one-step treatment of osteochondral defects of the talus with matrix-assisted bone marrow stimulation with a cell-free hyaluronic acid 3D matrix.

INDICATIONS

Symptomatic osteochondral defects of the talus (1-2 cm², ICRS III-IV).

CONTRAINDICATIONS

Large non-shouldered osteochondral defects (2 cm²) of the talus, arthritis, kissing lesions of the distal tibia, metabolic arthropathies, non-reconstructable defects, hindfoot malalignment, chronic inflammatory systemic disorders.

SURGICAL TECHNIQUE

Arthroscopic examination of the ankle joint and visualization of the osteochondral defect of the talus to confirm the indication via standard portals. First, debridement of the osteochondral defect with arthroscopic curette or shaver, removal of loose fragments, resection of the sclerotic bone via shaver and measurement of the defect size. Second, multiple perforation of the subchondral plate to recruit mesenchymal stem cells from the underlying bone marrow by an microfracturing awl to stimulate the differentiation of fibrocartilaginous repair tissue in the defect zone. Then, the cell-free hyaluronic acid 3D matrix is placed into the defect via arthroscopic forceps and modulated by a probe to avoid detachment of the matrix by ankle joint movement.

POSTOPERATIVE MANAGEMENT

Postoperative management includes movement restrictions for pro- and supination but free passive dorsal extension and plantar flexion. No weight-bearing is allowed for 6 weeks.

RESULTS

Twenty-three patients (male: 11/women: 12) with a mean age of 33 years (range: 18-56) and a minimum follow-up of 24 months were included in this retrospective two-center study. The mean values for Foot and Ankle Outcome Score (FAOS) were 79 (range 33-93), for Tegner score 3 (range: 1-5) and the Visual analog scale (VAS) pain 1 (range: 0-3) and VAS function 2 (range: 0-5). At follow-up, MRI was available in 17 of 23 patients. MRI results showed a mean Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score of 81 (range: 65-90). Complications were not observed during the follow-up period.

AMIC for traumatic focal osteochondral defect of the talar shoulder: a 5 years follow-up prospective cohort study

BACKGROUND

Autologous Matrix-Induced Chondrogenesis (AMIC) is addressed to osteochondral defects of the talus. However, evidence concerning the midterm efficacy and safety of AMIC are limited. This study assessed reliability and feasibility of AMIC at 60 months follow-up. We hypothesize that AMIC leads to good clinical outcome at midterm follow-up.

METHODS

Surgeries were approached with an arthrotomy via malleolar osteotomy. A resorbable porcine I/III collagen membrane (Chondro-Gide®, Geistlich Pharma AG, Wolhusen, Switzerland) was used. Patients were followed at 24 and 60 months. The primary outcome of interest was to analyse the Foot Function Index (FFI), and the subscale hindfoot of the American Orthopaedic Foot and Ankle Score (AOFAS). Complications such as failure, revision surgeries, graft delamination, and hypertrophy were also recorded. The secondary outcome of interest was to investigate the association between the clinical outcome and patient characteristics at admission.

RESULTS

Data from 19 patients were included. The mean age at admission was 47.3 ± 13.2 years, and the mean BMI 24.1 ± 4.9 kg/m². 53% (10 of 19 patients) were female. At a mean of 66.2 ± 11.6 months, the FFI decreased at 24-months follow-up of 22.5% (P = 0.003) and of further 1.3% (P = 0.8) at 60-months follow-up. AOFAS increased at 24-months follow-up of 17.2% (P = 0.003) and of further 3.4 (P = 0.2) at 60-months follow-up. There were two symptomatic recurrences within the follow-up in two patients. There was evidence of a strong positive association between FFI and AOFAS at baseline and the same scores last follow-up (P = 0.001 and P = 0.0002, respectively).

CONCLUSION

AMIC enhanced with cancellous bone graft demonstrated efficacy and feasibility for osteochondral defects of the talus at five years follow-up. The greatest improvement was evidenced within the first two years. These results suggest that clinical outcome is influenced by the preoperative status of the ankle. High quality studies involving a larger sample size are required to detect seldom complications and identify prognostic factors leading to better clinical outcome.

LEVEL OF EVIDENCE

II, prospective cohort study.

Effects of adipose tissue-derived stromal vascular fraction on osteochondral defects treated by hyaluronic acid-based scaffold: An experimental study

OBJECTIVES

This study aims to evaluate the effect of adipose-derived stromal vascular fraction (SVF) on osteochondral defects treated by hyaluronic acid (HA)-based scaffold in a rabbit model.

MATERIALS AND METHODS

Eighteen white New Zealand rabbits were randomly grouped into the experimental group (n=9) and control group (n=9). In all groups, osteochondral defects were induced on the weight-bearing surfaces of the right femoral medial condyles, and a HA-based scaffold was applied to the defect area with microfractures (MFs). In this study, 1 mL of adipose-derived SVF was injected into the knee joints of the rabbits in the experimental group. For histological and macroscopic evaluation, four rabbits were randomly selected from each group at Week 4, and the remaining rabbits were sacrificed at the end of Week 8. Macroscopic assessments of all samples were performed based on the Brittberg scoring system, and microscopic evaluations were performed based on the O'Driscoll scores.

RESULTS

Samples were taken at Weeks 4 and 8. At Week 4, the O'Driscoll scores were significantly higher in the control group than the experimental group (p=0.038), while there was no significant difference in the Brittberg scores between the two groups (p=0.108). At Week 8, the O'Driscoll score and Brittberg scores were statistically higher in the experimental group than in the control group (p=0.008 and p=0.007, respectively). According to the microscopic evaluation, at the end of Week 8, the cartilage thickness was greater in the experimental group, and nearly all of the defect area was filled with hyaline cartilage.

CONCLUSION

Application of adipose-derived SVF with MF-HA-based scaffold was better than MF-HA-based scaffold treatment in improving osteochondral regeneration. Therefore, it can be used in combination with microfracture and scaffold to accelerate cartilage regeneration, particularly in the treatment of secondary osteoarthritis.

Matrix-induced autologous chondrocyte implantation versus autologous matrix-induced chondrogenesis for chondral defects of the talus: a systematic review

INTRODUCTION

Chondral defects of the talus are common and their treatment is challenging.

SOURCE OF DATA

Recent published literatures.

AREAS OF AGREEMENT

Membrane-induced Autologous Chondrocyte Implantation (mACI) and Autologous Matrix-Induced Chondrogenesis (AMIC) have been proposed as management for chondral defects of the talus.

AREAS OF CONTROVERSY

It is debated whether AMIC provides greater outcomes compared to mACI for chondral regeneration. Several clinical studies showed controversial results, and the best treatment has not yet been clarified.

GROWING POINTS

To investigate whether AMIC provide superior outcomes than mACI at midterm follow-up.

AREAS TIMELY FOR DEVELOPING RESEARCH

AMIC exhibits similar clinical results to mACI. However, AMIC involves one single surgical procedure, no articular cartilage harvest and hence no morbidity from it, no need for chondrocyte expansion in a separate laboratory setting. For these reasons, AMIC may be preferred to mACI.

[Update on the Operative Treatment of Cartilage Defects]

Focal cartilage defects lead to swelling, significant pain and loss of function of the affected joint. Additionally, they are linked to early onset of osteoarthritis. Often young and active patients are especially susceptible due to the high stress placed on their joints. A vast amount of treatment options is available to orthopaedic surgeons to cure cartilage defects of the knee, hip, shoulder, elbow and ankle joints. This article serves to give an overview of these available treatment options and to explain the expected outcomes.

Comparison of Chitosan-Based Liquid Scaffold and Hyaluronic Acid-Based Soft Scaffold for Treatment of Talus Osteochondral Lesions

BACKGROUND

The aim of this study was to evaluate the clinical and radiologic results of 2 different scaffolds with hyaluronan or chitosan-based structure used in the treatment of talus osteochondral lesions.

METHODS

Eighty-one patients who underwent chondral lesion repair with hyaluronan (n = 42) or chitosan-based (n = 39) scaffold were included. American Orthopaedic Foot & Ankle Society (AOFAS) and visual analog scale (VAS) scores were evaluated within and between groups preoperatively and at the 3rd, 12th, and 24th month postoperatively. In all patients, magnetic resonance imaging was performed between the 12 and 18th month postoperatively and compared with magnetic resonance observation of cartilage repair tissue (MOCART) scoring.

RESULTS

Within-group evaluations revealed significant improvements in AOFAS and VAS scores at postoperative 3 and 12 months. The postoperative 24th-month results of AOFAS scores in any group did not differ significantly from the 12th-month results. There was no significant difference between the groups in comparison of AOFAS, VAS, and MOCART scores at any time period.

CONCLUSION

Both scaffolds were found to be effective in cartilage healing but had no clinical or radiologic superiority to each other. This is the first study to compare the use of different cell-free scaffold types in osteochondral defects of the talus.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.