Clinical outcomes after arthroscopic microfracture for osteochondral lesions of the talus are better in patients with decreased postoperative subchondral bone marrow edema.

PURPOSE: Magnetic resonance imaging (MRI) findings of subchondral bone marrow edema (SBME) in osteochondral lesions of the talus (OLT) after arthroscopic microfracture are associated with poor clinical outcomes. However, the relationship between SBME volume change and clinical outcomes has not been analyzed. It was hypothesized that clinical outcomes correlated with SBME volume change and extent of cartilage regeneration in patients with OLT. METHODS: 64 patients who underwent arthroscopic microfracture for OLT were followed up for more than 2 years. SBME volume change was measured by comparing preoperative and 2-year follow-up MRI. Clinical outcomes were assessed using the visual analogue scale (VAS) and the American orthopedic foot and ankle society ankle-hindfoot scale (AOFAS) at the 2-year and final follow-up. To compare clinical outcomes, patients were categorized into two groups: decreased SBME (DSBME) group (cases without SBME on either MRI or with a decreased SBME volume between the MRIs) and increased SBME (ISBME) group (cases with new SBME on postoperative MRI or with an increased SBME volume between the MRIs). Additionally, the effects of age, sex, body mass index, symptom duration, OLT size, OLT location, containment/uncontainment, preoperative subchondral cysts, pre- and postoperative SBME volumes, and MRI observation of cartilage repair tissue score on clinical outcomes were analyzed. RESULTS: The DSBME group included 45 patients, whereas the ISBME group included 19. The mean age was 40.1 ± 17.2 years, and mean follow-up period was 35.7 ± 18.3 months. Preoperative SBME volume was significantly higher in the DSBME group, while the ISBME group had higher volumes at the final follow-up. In both groups, the VAS and AOFAS scores significantly improved at the final follow-up (p < 0.001, < 0.001). The VAS scores were significantly lower in the DSBME group at the 2-year and final follow-up (p = 0.004, 0.011), while the AOFAS scores were significantly higher (p = 0.019, 0.028). Other factors including cartilage regeneration did not affect clinical outcomes. CONCLUSION: SBME volume change correlated with clinical outcomes after arthroscopic microfracture for OLT. Clinical outcomes were worse in patients with new postoperative SBME and increased postoperative SBME volume. In patients with an unsatisfactory clinical course that show decreased SBME via postoperative MRI, an extended follow-up in a conservative manner could be considered. LEVEL OF EVIDENCE: Level III.

Severe Bone Marrow Edema Among Patients Who Underwent Prior Marrow Stimulation Technique Is a Significant Predictor of Graft Failure After Autologous Chondrocyte Implantation.

BACKGROUND: Autologous chondrocyte implantation (ACI) is a well-established cartilage repair procedure; however, numerous studies have shown higher ACI graft failure rates after prior marrow stimulation techniques (MSTs). PURPOSE: To identify which factors may predict decreased graft survival after ACI among patients who underwent a prior MST. A secondary aim was to investigate the specificity of these predictors. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: In this review of prospectively collected data, the authors analyzed 38 patients who had failed prior MST surgery and subsequently underwent collagen-covered ACI (case group). The case group was divided into graft failure ACI (n = 8, 21%) and successful ACI (n = 30, 79%). Fourteen clinical variables were categorized and analyzed to determine predictors for failure of the ACI graft: age, body mass index, sex, defect characteristics (number, size, location, etiology, type), presence of kissing lesion, intraoperative presence of intralesional osteophyte, time between an MST and ACI, previous surgery, duration of the symptoms, and concomitant surgical procedure. Preoperative magnetic resonance imaging (MRI) was used to evaluate the severity of subchondral bone marrow edema (BME), graded I (absent) to IV (severe), and the presence of subchondral cyst, hypertrophic sclerosis, and intralesional osteophyte. The effects of these MRI findings on the graft survivor were also investigated. Concurrently, a control group without a prior MST was matched to investigate the specificity of the previously determined predictors. These patients were matched individually according to age, sex, body mass index, and outcome of the procedure (failure [n = 8] or successful [n = 30] per the case group). RESULTS: In the case group, the presence of preoperative severe BME was significantly higher among patients with failed ACI as compared with patients with successful ACI (P < .001). In the control group, the presence of severe BME was not significantly different between the failure and successful groups (P = .747). The ACI graft failure rate among patients with a prior MST and preoperative grade IV BME was 83.7% at 5 years postoperatively, resulting in a significantly lower survival rate as compared with patients with a prior MST and without severe BME (5-year graft failure rate, 6.5%; P < .001). All the other parameters did not differ significantly. CONCLUSION: After a prior MST, the presence of grade IV BME by MRI was a predictive factor for graft failure among patients who then underwent second-generation ACI.

Degree of preoperative subchondral bone edema is not associated with pain and graft outcomes after matrix-induced autologous chondrocyte implantation.

BACKGROUND: Matrix-induced autologous chondrocyte implantation (MACI) is an established technique for the repair of knee chondral defects. While a number of factors may affect the clinical outcome, little is known about the influence of subchondral bone abnormalities at the time of surgery on pain and graft outcomes after MACI. PURPOSE: To investigate the association between subchondral bone marrow edema within 3 months before MACI surgery on preoperative and postoperative reported pain and symptoms as well as postoperative graft outcomes. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: This retrospective study was undertaken in 56 patients undergoing MACI with clinical and radiological assessments before surgery and at 3, 12, 24, and 60 months after surgery. Patients were assessed using the Pain and Symptoms subscales of the Knee Injury and Osteoarthritis Outcome Score (KOOS). High-resolution magnetic resonance imaging (MRI) was used to evaluate the severity of preoperative subchondral bone marrow edema, while graft infill and an MRI composite graft score were evaluated after surgery via the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. Linear regression utilizing generalized estimating equations was used to investigate the association between preoperative subchondral bone marrow edema scores and preoperative and postoperative KOOS subscores as well as postoperative MRI-based scores of graft repair. RESULTS: The degree of preoperative subchondral bone marrow edema was not significantly associated with postoperative outcomes, whereby there was no evidence of a difference between edema subgroups over all time points for the KOOS-Pain subscore (P = .644), KOOS-Symptoms subscore (P = .475), or MRI composite score (P = .685) after adjustment for potential confounders of age, body mass index, defect size, and defect location. CONCLUSION: No association was demonstrated between the severity of preoperative subchondral bone marrow edema with postoperative patient-reported knee pain or symptoms or postoperative graft repair assessed via MRI.