A review of self-supervised, generative, and few-shot deep learning methods for data-limited magnetic resonance imaging segmentation.

Magnetic resonance imaging (MRI) is a ubiquitous medical imaging technology with applications in disease diagnostics, intervention, and treatment planning. Accurate MRI segmentation is critical for diagnosing abnormalities, monitoring diseases, and deciding on a course of treatment. With the advent of advanced deep learning frameworks, fully automated and accurate MRI segmentation is advancing. Traditional supervised deep learning techniques have advanced tremendously, reaching clinical-level accuracy in the field of segmentation. However, these algorithms still require a large amount of annotated data, which is oftentimes unavailable or impractical. One way to circumvent this issue is to utilize algorithms that exploit a limited amount of labeled data. This paper aims to review such state-of-the-art algorithms that use a limited number of annotated samples. We explain the fundamental principles of self-supervised learning, generative models, few-shot learning, and semi-supervised learning and summarize their applications in cardiac, abdomen, and brain MRI segmentation. Throughout this review, we highlight algorithms that can be employed based on the quantity of annotated data available. We also present a comprehensive list of notable publicly available MRI segmentation datasets. To conclude, we discuss possible future directions of the field-including emerging algorithms, such as contrastive language-image pretraining, and potential combinations across the methods discussed-that can further increase the efficacy of image segmentation with limited labels.

Use of Extracellular Matrix Cartilage Allograft May Improve Infill of the Defects in Bone Marrow Stimulation for Osteochondral Lesions of the Talus.

PURPOSE: To evaluate the effectiveness of extracellular matrix cartilage allograft (EMCA) as an adjuvant to bone marrow stimulation (BMS) compared with BMS alone in the treatment of osteochondral lesions of the talus. METHODS: A retrospective cohort study comparing patients treated with BMS with EMCA (BMS-EMCA group) and BMS alone (BMS group) between 2013 and 2019 was undertaken. Clinical outcomes were evaluated with the Foot and Ankle Outcome Score (FAOS) preoperatively and postoperatively. Postoperative magnetic resonance imaging (MRI) scans were evaluated using the modified Magnetic Resonance Observation of Cartilage Repair Tissue score. Comparisons between groups were made with the Mann-Whitney U test for continuous variables and the Fisher exact test for categorical variables. RESULTS: Twenty-four patients underwent BMS with EMCA (BMS-EMCA group), and 24 patients underwent BMS alone (BMS group). The mean age was 40.8 years (range, 19-60 years) in the BMS-EMCA group and 47.8 years (range, 24-60 years) in the BMS group (P = .060). The mean follow-up time was 20.0 months (range, 12-36 months) in the BMS-EMCA group and 26.9 months (range, 12-55 months) in the BMS group (P = .031). Both groups showed significant improvements in all FAOS subscales. No significant differences between groups were found in all postoperative FAOS values. The mean Magnetic Resonance Observation of Cartilage Repair Tissue score in the BMS-EMCA group was higher (76.3 vs 66.3) but not statistically significant (P = .176). The MRI analysis showed that 87.5% of the BMS-EMCA patients had complete infill of the defect with repair tissue; however, fewer than half of the BMS patients (46.5%) had complete infill (P = .015). CONCLUSIONS: BMS with EMCA is an effective treatment strategy for osteochondral lesions of the talus and provides better cartilage infill in the defect on MRI. However, this did not translate to improved functional outcomes compared with BMS alone in the short term. Additionally, according to analysis of the minimal clinically important difference, there was no significant difference in clinical function scoring between the 2 groups postoperatively. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Concentrated Bone Marrow Aspirate May Decrease Postoperative Cyst Occurrence Rate in Autologous Osteochondral Transplantation for Osteochondral Lesions of the Talus.

PURPOSE: To clarify if the use of concentrated bone marrow aspirate (CBMA) would affect both postoperative functional outcomes and magnetic resonance imaging (MRI) outcomes compared with those of autologous osteochondral transplantation (AOT) alone; in addition, to assess the efficacy of CBMA reducing the presence of postoperative cyst formation following AOT in the treatment of osteochondral lesions of the talus. METHODS: Fifty-four (92%) of 59 eligible patients who underwent AOT between 2004 and 2008 were retrospectively assessed at a minimum of 5-year follow-up. Twenty-eight patients were treated with AOT and CBMA (AOT/CBMA group) and 26 patients were treated with AOT alone (AOT-alone group). Clinical outcomes were evaluated using the Foot and Ankle Outcome Scores (FAOS) and Short-Form 12 (SF-12) preoperatively and at final follow-up. Postoperative MRI was evaluated with the modified Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) scoring system. Cyst formation was also evaluated on postoperative MRI. RESULTS: The mean FAOS and SF-12 significantly improved in both the AOT/CBMA and AOT-alone groups, but there were no statistical differences between groups in FAOS (80.5 vs 75.5, P = .225) and SF-12 (71.1 vs 69.6, P = .756) at final follow-up. Additionally, there was no difference in the mean MOCART score (80.4 vs 84.3, P = .484); however, AOT/CBMA did result in a statistically lower rate of cyst formation (46.4% vs 76.9%, P = .022). No significant differences were found in the mean postoperative FAOS and SF-12 between patients with and without cysts postoperatively. CONCLUSIONS: CBMA reduced postoperative cyst occurrence rate in patients treated with AOT; however, CBMA did not result in significant differences in medium term functional outcomes and MOCART score in patients who underwent AOT. LEVEL OF EVIDENCE: Level III, retrospective comparative trial.

Allograft Compared with Autograft in Osteochondral Transplantation for the Treatment of Osteochondral Lesions of the Talus.

BACKGROUND: There is a paucity of clinical studies that compare the efficacy of autograft and allograft in osteochondral transplantation for treatment of osteochondral lesions of the talus (OLT). The purpose of the present study was to compare the clinical and radiographic outcomes following osteochondral transplantation with autograft or allograft for OLT. METHODS: A retrospective analysis comparing patients treated with autograft or allograft for OLT was performed. Clinical outcomes were evaluated with use of the Foot and Ankle Outcome Score (FAOS) and the Short Form-12 (SF-12) score. Magnetic resonance imaging (MRI) was evaluated with use of the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score. The rates of cyst occurrence, graft degradation, graft failure, and revision surgeries were also evaluated. RESULTS: Twenty-five nonrandomized patients with autograft and 16 with allograft were included, with a mean follow-up of 26 months in the autograft group and 22 months in the allograft group. There were no significant differences among all demographic variables between the autograft and allograft groups. The mean postoperative FAOS was significantly higher in the autograft group (81.9; 95% confidence interval [CI]: 78.6 to 85.2) than in the allograft group (70.1; 95% CI: 63.7 to 76.5; p = 0.006). Similarly, the mean postoperative SF-12 scores were significantly higher in the autograft group (74.7; 95% CI: 71.0 to 78.4) than in the allograft group (66.1; 95% CI: 61.2 to 71.0; p = 0.021). MOCART scores were significantly better in the autograft group (87.1) than in the allograft group (75.5; p = 0.005). The rate of chondral wear on MRI was higher in the allograft group (53%) than in the autograft group (4%; p < 0.001). Cyst formation in the graft itself was more likely to occur in the allograft group (47%) than in the autograft group (8%; p = 0.017). The rate of secondary procedures for the graft was higher in the allograft group (25%) than in the autograft group (0%; p = 0.009). CONCLUSIONS: In this small nonrandomized cohort study, the procedures performed with use of an autograft provided better clinical and MRI outcomes than the allograft procedures. The rate of chondral wear on MRI was higher with allograft than with autograft, and allograft-treated patients had a higher rate of clinical failure. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Incidence of Coexisting Talar and Tibial Osteochondral Lesions Correlates With Patient Age and Lesion Location.

BACKGROUND: The incidence of coexisting osteochondral lesions (OCLs) of the tibia and talus has been negatively correlated with successful clinical outcomes, yet these lesions have not been extensively characterized. PURPOSE: To determine the incidence of coexisting tibial and talar OCLs, assess the morphologic characteristics of these lesions, and evaluate whether these characteristics are predictive of outcome. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: A total of 83 patients who underwent surgery for a talar OCL were evaluated for coexisting OCLs of the distal tibia with preoperative magnetic resonance images. Size, location, containment, International Cartilage Repair Society (ICRS) grade, patient age, and patient sex were analyzed for predictors of coexisting lesions or patient outcome. The talar and tibial surfaces were each divided into 9 zones, with 1 corresponding to the most anteromedial region and proceeding laterally and then posteriorly. The Foot and Ankle Outcome Score (FAOS) was evaluated pre- and postoperatively. RESULTS: Twenty-six patients (31%) had coexisting tibial and talar OCLs, with 9 (35%) identified as kissing lesions. Age correlated with coexisting lesion incidence, as older patients were more likely to have a coexisting tibial OCL (P = .038). More than half of talar OCLs were found in zone 4 (61%), whereas the majority of tibial OCLs were located in zones 2, 4, and 5 (19% each). Patients with coexisting lesions were more likely to have a lateral talar OCL (P = .028), while those without a coexisting tibial lesion were more likely to have a talar OCL in zone 4 (P = .016). There was no difference in FAOS result or lesion size between patients with and without coexisting OCLs, but patients with coexisting lesions were more likely to have an ICRS grade 4 talar OCL (P = .034). For patients with coexisting lesions, kissing lesions were more likely to be located in zone 6 (P = .043). There was no difference in OCL size or containment between kissing and nonkissing coexisting OCLs. CONCLUSION: The incidence of coexisting talar and tibial OCLs may be more prevalent than what previous reports have suggested, with older patients being more likely to present with this pathology. The location of a talar OCL correlates with the incidence of a coexisting tibial OCL.

The Presence and Degree of Bone Marrow Edema Influence Midterm Clinical Outcomes After Microfracture for Osteochondral Lesions of the Talus.

BACKGROUND: Subchondral bone marrow edema (BME) has been associated with articular cartilage loss, with the potential to be a negative prognostic indicator for clinical outcomes after microfracture. However, no single study has investigated the association between BME and clinical outcomes after microfracture for osteochondral lesions of the talus (OLTs) at midterm follow-up. PURPOSE: To clarify the association between postoperative subchondral BME and clinical outcomes in patients treated with microfracture for OLTs at both short-term and midterm follow-up using a grading system that classified the extent of BME of the talus. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients who underwent microfracture between 2008 and 2013 were assessed at 2- and 4-year postoperative follow-up. BME was evaluated using magnetic resonance imaging, and the presence of subchondral BME was determined with fat-suppressed T2-weighted sequences. Clinical outcomes were evaluated using the Foot and Ankle Outcome Score (FAOS). P < .05 was considered to be statistically significant. RESULTS: Forty-three (83%) of 52 eligible patients were included. No significant differences were found in the FAOS between the BME and no BME groups at 2-year follow-up (83.1 ± 6.5 vs 88.6 ± 8.0, respectively; P = .109), but there was a significant difference at 4-year follow-up (77.5 ± 11.1 vs 84.7 ± 8.4, respectively; P = .041). A significant difference was found among BME grades at 4-year follow-up (grade 0: 84.7 ± 7.4, grade 1: 80.1 ± 10.5, grade 2: 74.0 ± 10.3, and grade 3: 67.5 ± 7.1; P = .035). A post hoc analysis showed significant differences between grades 0 and 2, 0 and 3, and 1 and 3 ( P = .041, .037, and .048, respectively). In addition, at 4-year follow-up, a significant correlation was noted between the FAOS and BME grade ( r = -0.453, P = .003) but not at 2-year follow-up ( r = -0.212, P = .178). Seventy-four percent of patients still had subchondral BME at 4-year follow-up after microfracture for OLTs. CONCLUSION: Patients with subchondral BME at midterm follow-up after microfracture for OLTs had worse clinical outcomes than those without subchondral BME. In addition, the degree of subchondral BME at midterm follow-up was correlated with clinical outcomes. However, at short-term follow-up, there were no significant differences in clinical outcomes based on both the presence and degree of BME, and no correlation was found between clinical outcomes and the degree of BME. The current study suggests that BME at short-term follow-up is a normal physiological reaction. However, BME at midterm follow-up after microfracture for OLTs may be pathological and is associated with poorer clinical outcomes.

Effect of the Containment Type on Clinical Outcomes in Osteochondral Lesions of the Talus Treated With Autologous Osteochondral Transplantation.

BACKGROUND: Uncontained-type osteochondral lesions of the talus (OLTs) have been shown to have inferior clinical outcomes after treatment with bone marrow stimulation. While autologous osteochondral transplantation (AOT) is indicated for larger lesions, no study has reported on the prognostic significance of the containment of OLTs treated with the AOT procedure. PURPOSE: To clarify the effect of the containment of OLTs on clinical and radiological outcomes in patients who underwent AOT for OLTs. STUDY DESIGN: Case control study; Level of evidence, 3. METHODS: A retrospective cohort study comparing patients with contained-type and uncontained-type OLTs was undertaken to include all patients who underwent AOT for the treatment of OLTs between 2006 and 2014. Analyses were performed by grouping the patients according to the containment type. Clinical outcomes were evaluated using the Foot and Ankle Outcome Score (FAOS) and the 12-Item Short Form Health Survey (SF-12) preoperatively and at final follow-up. Magnetic resonance imaging (MRI) at 2 years' follow-up was evaluated with the modified magnetic resonance observation of cartilage repair tissue (MOCART) score. Multivariate regression models were used to evaluate factors affecting postoperative FAOS, SF-12, and MOCART scores. RESULTS: Ninety-four patients were included: 31 patients with a contained-type OLT and 63 patients with an uncontained-type OLT. The median patient age was 34 years (interquartile range [IQR], 28-48 years) in the contained-type group and 36 years (IQR, 27-46 years) in the uncontained-type group. The median follow-up time was 45 months (IQR, 38-63 months) in the contained-type group and 52 months (IQR, 40-66 months) in the uncontained-type group. The median FAOS and SF-12 scores improved significantly after surgery in both contained-type and uncontained-type lesions ( P < .001). The median postoperative FAOS score of patients with contained-type OLTs was higher than that of patients with uncontained-type OLTs (91.7 vs 85.0, respectively; P = .009), but no significant differences were found between the contained-type and uncontained-type groups for postoperative SF-12 and MOCART scores. The multivariate regression models showed that patients with contained-type OLTs had an approximately 10-point better score on the FAOS compared with patients with uncontained-type OLTs ( P = .006). There was a nonsignificant trend for the rate of cystic occurrence in uncontained-type OLTs to be higher than that of contained-type OLTs (55.6% vs 38.7%, respectively; P = .125). CONCLUSION: Patients with contained-type OLTs experienced better clinical outcomes than those with uncontained-type OLTs after AOT for the treatment of OLTs. However, the AOT procedure still provided good clinical and MRI outcomes in both contained-type and uncontained-type OLTs at midterm follow-up.

Subchondral Bone Degradation After Microfracture for Osteochondral Lesions of the Talus: An MRI Analysis.

BACKGROUND: Microfracture is the most common cartilage-reparative procedure for the treatment of osteochondral lesions of the talus (OLTs). Damage to the subchondral bone (SCB) during microfracture may irreversibly change the joint-loading support of the ankle, leading to reparative fibrocartilage degradation over time. PURPOSE: To investigate the morphological change in the SCB after microfracture for OLT by developing a novel magnetic resonance imaging (MRI) scoring system specifically for evaluating the SCB. Furthermore, this study assesses the influence of the morphological changes of the SCB on clinical outcomes based on the new score. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Forty-two patients who underwent microfracture for OLT were included. An SCB Health (SCBH) scoring system was developed according to the amount of edema, subchondral cyst diameter, and qualitative and thickness change in the SCB, with a total score of 12 indicating normal SCB. MRI was obtained postoperatively from 6 months to 1 year, 1 to 2 years, 2 to 4 years, and 4 to 6 years. The Foot and Ankle Outcome Score (FAOS) was evaluated preoperatively and at 2 years and final follow-up. RESULTS: The mean patient age was 38.4 ± 15.6 years, with a mean follow-up of 51.7 ± 22.8 months. The mean FAOS improved significantly from 57.8 ± 14.4 preoperatively to 84.3 ± 7.2 at 24 months ( P < .001) and decreased to a final mean value of 77.1 ± 12.6 ( P < .001). The mean SCBH score decreased from 8.6 ± 1.9 preoperatively to 7.1 ± 1.8 on the first follow-up MRI ( P < .001) and significantly decreased to 5.9 ± 2.3 on the fourth follow-up MRI ( P < .001). Subchondral cysts were noticeably worse at the fourth follow-up MRI than at the first and second ( P < .001, P = .006, respectively). There was a positive correlation between the final FAOS and the SCBH score on the third and fourth follow-up MRI ( r = 0.55, P < .001; r = 0.70, P < .001, respectively), but no correlation was found on the first and second follow-up. CONCLUSION: The SCBs following microfracture for OLT were not restored at midterm follow-up. There was a significant decrease of the overall SCBH score over time. Noticeably, subchondral cysts deteriorated over time consistently. In addition, the SCBH score at midterm follow-up was positively correlated with clinical outcomes. Lasting morphological changes in the SCB may be indicative of longer-term failure of the microfracture procedure.

Magnetic Resonance Imaging Evidence of Postoperative Cyst Formation Does Not Appear to Affect Clinical Outcomes After Autologous Osteochondral Transplantation of the Talus.

PURPOSE: To identify potential cysts using magnetic resonance imaging (MRI) after autologous osteochondral transplantation (AOT) for osteochondral lesions of the talus (OLTs) as well as to determine the effect of cysts on short-term clinical outcomes. METHODS: Eighty-nine MRI scans of 37 patients who had AOT for an OLT were evaluated. Radiographic variables examined included cyst presence, cyst location, bone edema, and cartilage integrity. Patient clinical variables recorded and examined for association with the presence of a cyst included gender, age, preoperative lesion size, size and number of osteochondral graft used, symptoms reported, and pre- and postoperative Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) scores measured at final follow-up. RESULTS: Twenty-four patients (64.8%) had MRI evidence of cystic change after AOT for an OLT at a mean MRI follow-up time of 15 months after surgery (range 2-54). Patients with presence of a cyst after surgery were older (mean age, 42.7 years) than those without cysts (mean age, 32.7 years) (P = .041), and among patients with a cyst, older patients more often had involvement of the subchondral plate (57.3 v 36.7 years) (P < .001). No other variables associated with cyst formation had statistical significance. Mean patient FAOS scores increased from 50 (±19) preoperatively to 87 (±8) postoperatively. Mean SF-12 scores increased from 52 (±18) preoperatively to 85 (±6) postoperatively. Patients not identified as having a cyst had lower SF-12 (P = .028) and FAOS (P = .032) preoperative scores and more improvement in SF-12 (P = .006) and FAOS (P = .016) scores than patients with cysts. CONCLUSIONS: Postoperative cyst formation on MRI was found to be a common occurrence after AOT for OLT. Although increasing age was related to increased cyst prevalence, the clinical impact of cyst formation was not found to be significant at short-term follow-up. Continued long-term longitudinal follow-up of postoperative cysts is needed. LEVEL OF EVIDENCE: Level IV, prognostic case series.

Autologous Osteochondral Transplantation for Osteochondral Lesions of the Talus: Does Previous Bone Marrow Stimulation Negatively Affect Clinical Outcome?

PURPOSE: To determine if functional outcomes and magnetic resonance imaging (MRI) outcomes were significantly different between patients receiving primary autologous osteochondral transplantation (AOT) and patients receiving secondary AOT surgery after failed microfracture. METHODS: A group of 76 patients enrolled into the Foot and Ankle Service between 2006 and 2012 was retrospectively analyzed. Patient-reported outcomes were evaluated in 76 patients using the Foot and Ankle Outcome Score (FAOS). Superficial and deep tissues at the repaired defect site, as well as the adjacent normal cartilage, were analyzed using quantitative T2 mapping MRI. Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) allowed for morphological evaluation of the repair tissue. The mean clinical follow-up time was 51 ± 23 months (range, 12 to 97 months), and the mean MRI follow-up time was 26 months (range, 24 to 36 months). RESULTS: Twenty-two patients received primary AOT and 54 received secondary AOT after failed microfracture. Patient characteristics between groups were similar with regard to age, gender, lesion size, and follow-up time. The mean postoperative FAOS was 10 points higher in the primary AOT group (83.2 ± 17.0) compared with the secondary AOT group (72.4 ± 19.4) (P = .01). Regression analysis showed that secondary AOT patients preoperative to postoperative change in FAOS was 9 points lower than in primary AOT patients after adjustment for age, preoperative FAOS, and lesion size (P = .045). The mean MOCART score, superficial T2 and deep T2 values, and the difference between normal and repair cartilage T2 values were not significantly different between groups. Lesion size was negatively correlated with MOCART scores (ρ = -0.2, P = .04), but positively correlated with difference in T2 values between repair and adjacent normal cartilage in the superficial layer (ρ = 0.3, P = .045). CONCLUSIONS: Primary AOT shows better functional outcomes compared with secondary AOT after failed microfracture in patients with similar characteristics and lesion size. No significant differences in T2 mapping relaxation times and MOCART scores were identified. LEVEL OF EVIDENCE: Level III, case control study.

Arthroscopic Bone Marrow Stimulation and Concentrated Bone Marrow Aspirate for Osteochondral Lesions of the Talus: A Case-Control Study of Functional and Magnetic Resonance Observation of Cartilage Repair Tissue Outcomes.

PURPOSE: This study compares retrospective functional and magnetic resonance imaging (MRI) outcomes after arthroscopic bone marrow stimulation (BMS) with and without concentrated bone marrow aspirate (cBMA) as a biological adjunct to the surgical treatment of osteochondral lesions (OCLs) of the talus. METHODS: Twenty-two patients who underwent arthroscopic BMS with cBMA (cBMA/BMS group) for an osteochondral lesion (OCL) of the talus and 12 patients who underwent arthroscopic BMS (BMS alone) for an OCL of the talus were retrospectively reviewed. The Foot and Ankle Outcome Score (FAOS) pain subscale and Short Form 12 general health questionnaire physical component summary score (SF-12 PCS) provided patient-reported outcome scores pre- and postoperatively. MRI scans were assessed postoperatively using the magnetic resonance observation of cartilage repair tissue (MOCART) score. All patients had postoperative MRI performed at the 2-year postoperative visit, and quantitative T2 mapping relaxation time values were assessed in a subset of the cBMA/BMS group. RESULTS: The mean FAOS and SF-12 PCS scores improved significantly pre- to post-operatively (P < .01) at a mean follow-up of 48.3 months (range, 34 to 82 months) for the cBMA/BMS group and 77.3 months (range, 46 to 100 months) for the BMS-alone group. The MOCART score in the cBMA/BMS group was significantly higher than that in the BMS-alone group (P = .023). Superficial and deep T2 relaxation values in cBMA/BMS patients were higher in repair tissue compared with measurements in adjacent native articular cartilage (P = .030 and P < .001, respectively). CONCLUSIONS: BMS is an effective treatment strategy for treatment of OCLs of the talus and results in good medium-term functional outcomes. Arthroscopic BMS with cBMA also results in similar functional outcomes and improved border repair tissue integration, with less evidence of fissuring and fibrillation on MRI.

Autologous Osteochondral Transplantation for Osteochondral Lesions of the Talus.

BACKGROUND: Autologous osteochondral transplantation (AOT) is used to treat osteochondral lesions (OCLs) of the talus, typically reserved for lesions greater than 150 mm(2). Few studies exist examining the functional and magnetic resonance imaging (MRI) outcomes following this procedure. The purpose of this study was to investigate functional and MRI outcomes, including quantitative T2 mapping following AOT. METHODS: Eighty-five consecutive patients who underwent AOT were identified. Functional outcomes were assessed pre- and postoperatively using the Foot and Ankle Outcome Score (FAOS). The Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score was used to assess cartilage incorporation. Quantitative T2 MRI relaxation time of graft tissue and adjacent normal cartilage values were recorded in a subset of 61 patients. The mean clinical follow-up was 47.2 months, with mean MRI follow-up of 24.8 months. RESULTS: Mean FAOS improved pre- to postoperatively from 50 to 81 (P < .001). The mean MOCART score was 85.8. Lesion size was negatively correlated with MOCART score (r = -0.36, P = .004). Superficial T2 values in graft tissue were higher than control tissue (42.0 vs 35.8, P < .001). Deep T2 values in graft tissue were similar to the control values (30.9 vs 30.0, P = .305). Functional outcomes were similar in patients irrespective of whether they had previous microfracture or concomitant procedures. CONCLUSION: AOT was an effective treatment for large OCLs of the talus in the current study. MOCART scoring indicated good structural integrity of the graft. Quantitative T2 mapping suggests that graft tissue may not always mirror native hyaline cartilage. The long-term implications of this are not yet known. LEVEL OF EVIDENCE: Level IV, case series.

Anterolateral tibial osteotomy for accessing osteochondral lesions of the talus in autologous osteochondral transplantation: functional and t2 MRI analysis.

BACKGROUND: Autologous osteochondral transplantation (AOT) is a primary treatment strategy for large or cystic osteochondral lesions of the talus (OLT) or a secondary replacement strategy after failed bone marrow stimulation. The technique requires perpendicular access to the talar dome, which is often difficult to obtain for posterior or lateral lesions. Traditional methods to access these areas have required disruption of the syndesmotic complex with concern over osteotomy reduction, malalignment, and ligament disruption. An alternate to these traditional methods of access is an anterolateral tibial osteotomy. The purpose of this study was to report functional and magnetic resonance imaging (MRI) outcomes in a series of patients that underwent AOT for treatment of an OLT via an anterolateral tibial osteotomy. METHODS: Records of patients that underwent an anterolateral tibial osteotomy for AOT were retrospectively reviewed. Pre- and postoperative Foot and Ankle Outcome Scores (FAOS) and demographic data were recorded. Magnetic resonance observation of cartilage repair tissue (MOCART) was used to assess morphologic state of tibial cartilage at the repair site of the osteotomy. Quantitative T2 mapping MRI was analyzed in the superficial and deep cartilage layers of the repair site of the osteotomy and in adjacent normal cartilage to serve as control tissue. Seventeen patients with a mean age of 36.9 (range, 17-76) years underwent anterolateral tibial osteotomy with a mean follow-up of 64 (range, 29 to 108) months. MOCART data were available in 9 of 17 patients, and quantitative T2 mapping was available in 6 patients. RESULTS: FAOS significantly improved from an average 39.2 (range, 14 to 66) out of 100 points preoperatively to 81.2 (range, 19 to 98) postoperatively (P < .01). The average MOCART score was 73.9 out of 100 points (range, 40 to 100). Quantitative T2 analysis demonstrated relaxation times that were not significantly different from the normal native cartilage in both the deep half and superficial half of interface repair tissue (P > .05). CONCLUSION: This study demonstrated that the anterolateral tibial osteotomy was a reasonable alternative for accessing centrolateral or posterolateral OLT for AOT with limited morbidity associated with the osteotomy. The evidence demonstrated adequate osteotomy and cartilaginous healing with improvement in functional outcome scores at medium-term follow-up. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Functional and MRI outcomes after arthroscopic microfracture for treatment of osteochondral lesions of the distal tibial plafond.

BACKGROUND: Osteochondral lesions of the distal tibial plafond are uncommon compared with talar lesions. The objective of this study was to assess functional and magnetic resonance imaging (MRI) outcomes following microfracture for tibial osteochondral lesions. METHODS: Thirty-one tibial osteochondral lesions in thirty-one ankles underwent arthroscopic microfracture. The Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) general health questionnaire were used to obtain patient-reported functional outcome scores preoperatively and postoperatively. MRI scans were assessed postoperatively with use of the Magnetic Resonance Observation of Cartilage Repair Tissue (MOCART) score for twenty-three ankles. RESULTS: The average age was thirty-seven years (range, fifteen to sixty-eight years), and the average lesion area was 38 mm(2) (range, 7.1 to 113 mm(2)). Twelve ankles had a kissing lesion on the opposing surface of the talus, and two ankles had a concomitant osteochondral lesion elsewhere on the talus. FAOS and SF-12 scores were significantly improved (p < 0.01) at the time of follow-up, at an average of forty-four months. The average postoperative MOCART score was 69.4 (range, 10 to 95), with a lower score in the ankles with kissing lesions (62.8) than in the ankles with an isolated lesion (73.6). Increasing age negatively impacted improvement in SF-12 (p < 0.01) and MOCART (p = 0.04) scores. Increasing lesion area was negatively correlated with MOCART scores (p = 0.04) but was not associated with FAOS or SF-12 scores. Lesion location and the presence of kissing lesions showed no association with functional or MRI outcomes. CONCLUSIONS: Arthroscopic microfracture provided functional improvements, but the optimal treatment strategy for tibial osteochondral lesions remains unclear. The repair tissue assessed on MRI was inferior to normal hyaline cartilage. The MRI outcomes appeared to deteriorate with increasing lesion area, and both functional and MRI outcomes appeared to deteriorate with increasing age. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Double-Plug Autologous Osteochondral Transplantation Shows Equal Functional Outcomes Compared With Single-Plug Procedures in Lesions of the Talar Dome: A Minimum 5-Year Clinical Follow-up.

BACKGROUND: Autologous osteochondral transplantation (AOT) is used for large (>100-150 mm(2)) or cystic osteochondral lesions (OCLs) of the talus. Larger lesions may require using more than 1 graft to fill the defect. While patients with larger OCLs treated with microfracture exhibit inferior clinical outcomes, there is little evidence regarding the effect of lesion size and number of grafts required on clinical and radiological outcomes after AOT. HYPOTHESIS: Larger OCLs of the talar dome treated by double-plug AOT (dp-AOT) have inferior clinical and radiological MRI outcomes compared with smaller OCLs requiring single-plug AOT (sp-AOT). STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Fourteen consecutive patients with a large OCL (mean, 208 ± 54 mm(2)) treated using dp-AOT with a minimum 5-year follow-up were matched by age and sex to a control cohort of 28 patients who underwent sp-AOT for a smaller OCL (mean, 74 ± 26 mm(2)) over the same period. Functional outcomes were assessed both pre- and postoperatively using the Foot and Ankle Outcome Score (FAOS) and Short Form-12 (SF-12) general health questionnaire. Mean follow-up was 85 months (range, 65-118 months). Latest postoperative MRI was evaluated with modified magnetic resonance observation of cartilage repair tissue (MOCART) score. RESULTS: There was no significant difference between groups demographically (P > .05). All patients with dp-AOT and sp-AOT showed a significant pre- to postoperative increase in FAOS and SF-12 scores (P < .001). When comparing preoperative scores for both groups, there was no statistical significance between sp-AOT and dp-AOT scores (FAOS, P = .719; SF-12, P = .947). There was no significant difference in functional scores between the 2 groups postoperatively for both FAOS (P = .883) and SF-12 (P = .246). Mean MOCART scores did not exhibit any statistically significant difference between groups (P = .475). Two patients complained of knee donor site stiffness (4.8%), which later resolved. CONCLUSION: Patients with large OCLs treated using a dp-AOT procedure did not show inferior clinical or radiological outcomes compared with those treated with sp-AOT at a minimum 5-year follow-up. The dp-AOT procedure is as effective as sp-AOT in treating larger OCLs of the talar dome in the intermediate term, with similar high postoperative clinical and radiological outcomes.

Chevron-type medial malleolar osteotomy: a functional, radiographic and quantitative T2-mapping MRI analysis.

PURPOSE: The purpose of this study was to retrospectively evaluate a large series of patients for functional, radiographic and MRI outcomes after a Chevron-type medial malleolar osteotomy. METHODS: Sixty-two patients underwent a Chevron-type medial malleolar osteotomy with a median follow-up of 34.5 months. Standard digital radiographs were used to determine bony union and the angle of the osteotomy relative to the longitudinal axis of the tibia. Morphologic and quantitative T2-mapping MRI was also analysed in 32 patients. RESULTS: Fifty-eight patients (94 %) reported being asymptomatic at the site of the medial malleolar osteotomy. The median time to healing on standard radiograph was 6 weeks (range, 4-6 weeks) with an angle of 31.7° ± 6.9°. Quantitative T2-mapping MRI analysis demonstrated that the deep half of interface repair tissue had relaxation times that were not significantly different from normal tibial cartilage. In contrast, interface repair tissue in the superficial half demonstrated significant prolongation from normal relaxation time values, indicating a more fibrocartilaginous repair. Four patients (6 %) reported pain post-operatively. CONCLUSION: A Chevron-type medial malleolar osteotomy demonstrates satisfactory healing and fixation, with fibrocartilaginous tissue evident superficially at the osteotomy interface. Further investigation is warranted in the form of longitudinal study to assess the long-term outcomes of medial malleolar osteotomy.

Reconstruction of the spring ligament using a peroneus longus autograft tendon transfer.

BACKGROUND: The spring (calcaneonavicular) ligament provides one of the main static supports of the medial arch of the foot. The purpose of this study was to retrospectively assess the results of patients having undergone reconstruction of the spring ligament using a peroneus longus tendon autograft left at its distal attachment and passed through the navicular followed by either a calcaneal or tibial drill hole, a technique not previously reported. MATERIALS AND METHODS: Thirteen consecutive patients (14 feet) (mean age, 63.5 +/- 12.3 years) undergoing flatfoot surgery with spring ligament reconstruction for cases in which lateral column lengthening failed to correct talonvavicular deformity were reviewed. The AOFAS, FAOS, and SF-36 were assessed along with standard weightbearing radiographs at a followup visit at a mean of 8.9 +/- 1.8 years after surgery. Hindfoot alignment and eversion strength were measured. RESULTS: The AOFAS ankle-hindfoot score increased from 43.1 to 90.3 (\hbox{p}\leq 0.001). The postoperative FAOS pain subscale and overall SF-36 were 83.7 (range, 67.9 to 100), and 77.3 (range 37.8 to 95.6) respectively. The AP first tarsometatarsal angle (p = 0.015), talonavicular coverage angle (p = 0.003), lateral calcaneal pitch (p = 0.002), and lateral talonavicular angle (p = 0.017) improved significantly and were within normal ranges postoperatively. The mean hindfoot alignment measured 2.7 degrees of valgus. All but one patient had normal (5/5) eversion strength. CONCLUSION: Reconstruction of the spring ligament resulted in few complications and might be considered as an alternative to arthrodesis in patients with ruptures of the spring ligament and deformity that does not correct fully with bony procedures alone.

Repair of a splenic artery aneurysm using a novel balloon-expandable covered stent.

We describe a case of endovascular exclusion of a splenic artery aneurysm. The repair utilized a novel balloon-expandable stent-graft.