Return to Play in Youth Athletes: Role of the Radiologist with Focus on the Upper Extremity.

Increase in youth sports participation, longer duration of play, and earlier starting points have increased the prevalence of acute and repetitive overuse musculoskeletal injuries. This rise in injury rates has led to increased efforts to better understand the susceptible sites of injury that are unique to the growing immature skeleton. Upper extremity injuries are currently the best studied, particularly those that occur among pediatric baseball players and gymnasts. The weak link in skeletally immature athletes is the growth plate complex that includes those injuries located at the epiphyseal and apophyseal primary physes and the peripherally located secondary physes. This article reviews the anatomy and function of these growth plate complexes, followed by a discussion of the pathophysiologic mechanisms, spectrum of imaging findings, and existing evidence-based guidelines for injury prevention and return to play.

Bone Bruise versus Fracture on MRI and the Relevance to Return to Play.

We review the spectrum of acute osseous injuries in athletes, ranging from osseous contusion (bone bruise) injuries to nondisplaced cortical fractures. The basic biomechanical concepts, underlying histopathologic changes, and characteristic magnetic resonance imaging (MRI) features of acute osseous injuries are presented. Bone bruise injuries of varying severity are highlighted to showcase the breadth of imaging findings on MRI and methods for characterizing such lesions. We emphasize the importance of accurately assessing patterns of injury on MRI to communicate more effectively with team medical staff and recognize the implications on return to play. This article offers the foundational tools for approaching bone bruise injuries in elite athletes to add value to the diagnosis and treatment of this unique patient population.

Stellate ganglion block for treating post-COVID-19 parosmia.

BACKGROUND: Post-COVID parosmia may be due to dysautonomia and sympathetic hyperresponsiveness, which can be attenuated by stellate ganglion block (SGB). This study evaluates SGB as a treatment for post-COVID olfactory dysfunction (OD). METHODS: Retrospective case series with prospective data of patients with post-COVID OD undergoing unilateral (UL) or bilateral (BL) SGB. Patients completed Brief Smell Identification Tests (BSIT) (12 points maximum) and post-procedure surveys including parosmia severity scores on a scale of 1 (absent) to 10 (severe). Scores were compared from before treatment (pre-SGB) to after first (SGB1) or second (SGB2) treatments in overall, UL, and BL cohorts. RESULTS: Forty-seven patients with post-COVID OD underwent SGB, including 23 UL and 24 BL. Twenty patients completed pre- and post-SGB BSITs (eight UL and 12 BL). Twenty-eight patients completed postprocedure surveys (11 UL and 17 BL). There were no differences in BSIT scores from pre-SGB to post-SGB1 or post-SGB2 for the overall (p = 0.098), UL (p = 0.168), or BL (p = 0.230) cohorts. Parosmia severity for the overall cohort improved from pre-SGB (8.82 ± 1.28) to post-SGB1 (6.79 ± 2.38) and post-SGB2 (5.41 ± 2.35), with significant differences from pre-SGB to post-SGB1 (p < 0.001) and pre-SGB to post-SGB2 (p < 0.001), but not post-SGB1 to post-SGB2 (p = 0.130). Number of parosmia triggers decreased for overall (p = 0.002), UL (p = 0.030) and BL (p = 0.024) cohorts. Quality of life (QOL) improved for all cohorts regarding food enjoyment, meal preparation, and socialization (p < 0.05). CONCLUSION: SGB may improve subjective parosmia and QOL for patients with post-COVID OD, however it may not affect odor identification. Further placebo-controlled studies are warranted.

Heterotopic Ossification and Platelet-Rich Plasma in Core Muscle Injuries: A Single-Institution Experience Over 6 Years.

BACKGROUND: A 2015 study of platelet-rich plasma (PRP) for groin injuries in National Football League (NFL) players alerted the authors to the possibility that PRP is associated with heterotopic ossification (HO). The current study of athletes seen between 2014 and 2019 provides a more comprehensive analysis of that observation. PURPOSE/HYPOTHESIS: This report describes the early results of groin surgery for athletes who had experienced failed PRP therapy performed by different practitioners and with an assortment of PRP techniques. The primary goal of this cohort study was to determine short-term clinical outcomes after surgery of PRP-treated patients. It was hypothesized that previous PRP treatment would be associated with the presence of HO among patients with core muscle injuries (CMIs). STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: All athletes seen at 1 institution and identified at their first visit as having received PRP for a CMI were followed and compared with patients with a CMI who had not previously received PRP. Although in many cases HO was observed on clinical examination or imaging, HO was identified intraoperatively in all surgical cases and confirmed pathologically. Successful surgery was defined as return to play at previously high levels of performance or greater as determined by the athletes' own assessments. All patients who had received PRP were followed for ≥2 years. RESULTS: Among 3642 patients with a new CMI seen between 2014 and 2019, 68 (1.9%) patients developed HO within the core muscles and/or adjacent soft tissues. Of the 68 patients, 60 (88.2%) were men, and the mean age was 34.5 years. Of the 68 patients, 62 (91.2%) were athletes and 44 (64.7%) had been treated previously with PRP. HO was observed in 24 (0.7%) patients without previous PRP treatment. Three athletes who received PRP retired early from sports because of HO and scar issues. In total, 22 of 28 (78.6%) NFL players who received PRP developed HO, compared with 0 (0%) of 28 randomly selected, age-, position-, and injury-matched NFL players. After surgical repair, 3-month success rates were 67.9% and 96.4%, respectively, in the PRP and non-PRP groups (P = .006). By 6 months postoperatively, PRP-treated patients were back to similarly high success rates compared with the non-PRP cohort. Scar tissue issues played a prominent role in the relative delay in definitive success. CONCLUSION: The present, more comprehensive study confirms the previous preliminary analysis that treating CMIs with PRP may be associated with HO.

Pediatric thrower's elbow: maturation-dependent MRI findings in symptomatic baseball players.

BACKGROUND: Elbow pain is common among youth baseball players and elbow MRI is increasingly utilized to complement the clinical assessment. OBJECTIVE: To characterize, according to skeletal maturity, findings on elbow MRI from symptomatic youth baseball players. MATERIALS AND METHODS: This IRB-approved, HIPAA-compliant retrospective study included pediatric (<18 years of age) baseball players with elbow pain who underwent MRI examinations between 2010 and 2021. Two radiologists, blinded to the outcome, independently reviewed examinations to categorize skeletal maturity and to identify osseous and soft tissue findings with consensus used to resolve discrepancies. Findings were compared between skeletally immature and mature patients and logistic regression models identified predictors of surgery. RESULTS: This study included 130 children (115 boys, 15 girls): 85 skeletally immature and 45 mature (12.8±2.3 and 16.2±1.0 years, respectively, p<0.01). Kappa coefficient for interobserver agreement on MRI findings ranged from 0.64 to 0.96. Skeletally immature children, when compared to mature children, were more likely to have elbow effusion (27%, 23/85 vs 9%, 4/45; p=0.03), medial epicondyle marrow edema (53%, 45/85 vs 16%, 7/45; p<0.01), avulsion fracture (19%, 16/85 vs 2%, 1/45; p=0.02), and juvenile osteochondritis dissecans (OCD, 22%, 19/85 vs 7%, 3/45; p=0.04), whereas skeletally mature children were more likely to have sublime tubercle marrow edema (49%, 22/45 vs 11%, 9/85; p<0.01) and triceps tendinosis (40%, 18/45 vs 20%, 17/85; p=0.03). Intra-articular body (OR=4.2, 95% CI 1.5-47.8, p=0.02) and osteochondritis dissecans (OR=3.7, 95% CI 1.1-11.9, p=0.03) were independent predictors for surgery. CONCLUSION: Differential patterns of elbow MRI findings were observed among symptomatic pediatric baseball players based on regional skeletal maturity. Intra-articular body and osteochondritis dissecans were independent predictors of surgery.

Bone bruise vs. non-displaced fracture on MRI: a novel grading system for predicting return-to-play.

OBJECTIVE: To devise an MRI grading scheme for osseous contusion patterns in elite hockey players for predicting return-to-play (RTP). METHODS: A retrospective review was performed to identify traumatic lower extremity osseous injuries in professional hockey players. A total of 28 injuries (17 players) were identified over a 10-year period. All had MRIs acquired at ≥ 1.5 T within a mean interval of 2 days from initial injury. MRIs were retrospectively reviewed by 3 musculoskeletal radiologists for osseous contusion pattern, classified as grade 1 (mild), 2 (moderate), or 3 (severe). Grade 3 contusions were further subdivided by the presence or absence of fracture, defined as discrete cortical disruption on MRI or follow-up CT. RTP was calculated from date of injury to next game played based on game log data. Statistical analysis was performed using ANOVA and post hoc unpaired t test. RESULTS: Mean RTP for grade 1, 2, and 3 injuries was 2.8, 4.5, and 20.3 days, respectively. Grade 3 injuries without and with cortical fractures had mean RTP of 18.3 and 21.4 days, respectively. ANOVA analysis between groups achieved statistical significance (p < 0.001). Post hoc t test demonstrated statistically significant differences between grade 3 and grades 1 (p < 0.001) and 2 (p < 0.001) injuries. There was no statistical difference in RTP between grade 3 subgroups without and with fracture (p = 0.327). CONCLUSION: We propose a novel MRI grading system for assessing severity of osseous contusions and predicting RTP. Clinically, there was no statistically significant difference in RTP between severe osseous contusions and nondisplaced fractures in elite hockey players.

Extensor carpi ulnaris tendon pathology and ulnar styloid bone marrow edema as diagnostic markers of peripheral triangular fibrocartilage complex tears on wrist MRI: a case-control study.

OBJECTIVES: To evaluate extensor carpi ulnaris (ECU) tendon pathology and ulnar styloid process bone marrow edema (BME) as diagnostic MRI markers for peripheral triangular fibrocartilage complex (TFCC) tears. METHODS: One hundred thirty-three patients (age range 21-75, 68 females) with wrist 1.5-T MRI and arthroscopy were included in this retrospective case-control study. The presence of TFCC tears (no tear, central perforation, or peripheral tear), ECU pathology (tenosynovitis, tendinosis, tear or subluxation), and BME at the ulnar styloid process were determined on MRI and correlated with arthroscopy. Cross-tabulation with chi-square tests, binary logistic regression with odds ratios (OR), and sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were used to describe diagnostic efficacy. RESULTS: On arthroscopy, 46 cases with no TFCC tear, 34 cases with central perforations, and 53 cases with peripheral TFCC tears were identified. ECU pathology was seen in 19.6% (9/46) of patients with no TFCC tears, in 11.8% (4/34) with central perforations and in 84.9% (45/53) with peripheral TFCC tears (p < 0.001); the respective numbers for BME were 21.7% (10/46), 23.5% (8/34), and 88.7% (47/53) (p < 0.001). Binary regression analysis showed additional value from ECU pathology and BME in predicting peripheral TFCC tears. The combined approach with direct MRI evaluation and both ECU pathology and BME yielded a 100% positive predictive value for peripheral TFCC tear as compared to 89% with direct evaluation alone. CONCLUSIONS: ECU pathology and ulnar styloid BME are highly associated with peripheral TFCC tears and can be used as secondary signs to diagnose tears. KEY POINTS: • ECU pathology and ulnar styloid BME are highly associated with peripheral TFCC tears and can be used as secondary signs to confirm the presence of TFCC tears. • If there is a peripheral TFCC tear on direct MRI evaluation and in addition both ECU pathology and BME on MRI, the positive predictive value is 100% that there will be a tear on arthroscopy compared to 89% with direct evaluation alone. • If there is no peripheral TFCC tear on direct evaluation and neither ECU pathology nor BME on MRI, the negative predictive value is 98% that there will be no tear on arthroscopy compared to 94% with direct evaluation alone.

Postoperative MR Imaging of the Pubic Symphysis and Athletic Pubalgia.

MR imaging evaluation can be valuable in patients with prior surgery for athletic pubalgia presenting with new, recurrent, or persistent groin pain. The clinical and interventional history as well as comparison with preoperative imaging is essential for imaging interpretation. Imagers should be aware of expected and unexpected postoperative findings. MR imaging findings concerning for infection, new injury, contralateral injury, or concomitant sources of symptoms (such as hip pathology) should be reported when present.

Spotty Bone Marrow: A Frequent MRI Finding in the Feet of Ballet Dancers.

INTRODUCTION: Bone marrow signal abnormalities on magnetic resonance imaging (MRI) are common in athletes. However, few studies evaluate the MRI appearance of bone marrow in the feet of ballet dancers. Our study aims to describe the "spotty bone marrow" (SBM) pattern in the tarsal bones of a cohort of ballet dancers, establishing its prevalence, distribution, potential associations, and evolution.
Methods: Eighty-six MRIs of 68 ankles in 56 ballet dancers were retrospectively reviewed for mar- row signal alterations, which were classified as focal or SBM (defined as patchy fluid-sensitive signal hyperintensity spanning more than one location or tarsal bone). When SBM involved the talus, its anatomic distribution in the bone and morphologic pattern were recorded. Additional osseous and soft tissue findings were documented. For subjects with more than one MRI of the same ankle, the SBM's evolution was monitored.
Results: Spotty bone marrow was identified in 44 ankles (65%). Spotty bone marrow was isolated to the talus (44%), present in all tarsal bones (25%), or distributed between the talus and one to three other tarsal bones (31%). In the talus, The SBM involved the entire bone (65%), the neck and body (31%), or the head and neck (4%). The SBM most commonly showed a random morphologic pattern (87%) but occasionally showed a peripheral predominance (13%). There was no statistically significant difference in the prevalence of other pathologies in ankles with and without SBM. In eight ankles with a follow-up MRI, the SBM worsened in one, remained stable in two, and improved in five ankles. None progressed to a stress fracture.
Conclusion: Spotty bone marrow is an MRI finding frequently encountered in ballet dancers. It is usually self-limiting and should not be misinterpreted as a more aggressive pathology.

Effectiveness of Hematoma Aspiration and Platelet-rich Plasma Muscle Injections for the Treatment of Hamstring Strains in Athletes.

INTRODUCTION: The effect of platelet-rich plasma (PRP) treatment on recovery in acute hamstring injuries is controversial. Previous study results are inconsistent, and a standardized therapeutic approach has not been established yet. PURPOSE: To assess the treatment effect using a combination of hematoma aspiration and muscle strain PRP injection in partial hamstring muscle tears (grade 2 strains) in athletes. METHODS: Magnetic resonance imaging of athletes with grade 2 hamstring strains were reviewed from 2013 to 2018. From 2013 to 2015, athletes were treated conservatively, and from 2016 to 2018, with a combination of ultrasound-guided hematoma aspiration and PRP muscle strain injection. The outcome, including return-to-play (in days) and recurrence rate, was compared retrospectively between both groups (conservative vs aspiration/PRP) using ANOVA and Fisher's exact test. There was no significant difference in age, type of sport, and muscle involvement (including injury grade/location, hamstring muscle type, and length/cross-sectional area of the strain). RESULTS: Fifty-five athletes (28 treated conservatively, 27 with hematoma aspiration/PRP injection) were included. Average return-to-play time (mean) was 32.4 d in the conservative group and 23.5 d in the aspiration/PRP group (P < 0.001). Recurrence rate of the hamstring strain was 28.6% (8/28) in the conservative treatment group and less than 4% (1/27) in the aspiration/PRP group (P = 0.025). CONCLUSIONS: Athletes with grade 2 hamstring strains treated with a combination of hematoma aspiration and PRP injection had a significantly shorter return-to-play and a lower recurrence rate compared with athletes receiving conservative treatment.

Ultrasound-guided Procedures Allow Delay of Definitive Treatment for Core Muscle Injuries.

INTRODUCTION: Core muscle injuries (CMI) are common in every sport. To minimize lost playing time, providers apply various nonsurgical treatments, including platelet-rich plasma, corticosteroids, ultrasound (US)-guided percutaneous tenotomy, and prolotherapy. Limited data exist with regard to their effectiveness. We chose to review a cohort of consecutive professional and collegiate athletes who sustained CMI at various points within their seasons and underwent a combination of US-guided percutaneous needle "tenotomy" and corticosteroid injections to complete the remainder of their seasons. METHODS: Twenty-five consecutive collegiate or professional athletes with CMI involving the rectus abdominis-adductor aponeurotic plate were included in this retrospective study. Athletes with concomitant symptomatic hip femoroacetabular impingement were included in the study. The primary outcome measure was whether athletes completed their seasons. Secondary measures were weeks played after the procedures (delay until surgery), need for repeat procedures, and outcomes after eventual surgery. Postoperative performance was assessed via interviews at 6 wk and 6 months postoperatively. RESULTS: Twenty-one of 25 (84%) athletes completed their seasons. On average, athletes returned to play 3 d (range, 1-9 d) after the procedures. Surgical repair was delayed a mean of 18 wk (range, 2-44 wk). Seven athletes had concomitant symptomatic femoroacetabular impingement and six underwent combined hip arthroscopy and core muscle repairs. Among 17 patients who eventually had core muscle surgery alone (no hip surgery), 82% (14 of 17) reported performing at their preinjury level at 6 wk. At 6 months, 96% of postop athletes (22 of 23) reported performing at their preinjury level. CONCLUSIONS: Temporizing CMI with US-guided percutaneous tenotomy and corticosteroid injections is effective in allowing continued sport participation among high-level athletes and does not negatively affect postoperative outcomes.

MRI nomenclature for musculoskeletal infection.

The Society of Skeletal Radiology (SSR) Practice Guidelines and Technical Standards Committee identified musculoskeletal infection as a White Paper topic, and selected a Committee, tasked with developing a consensus on nomenclature for MRI of musculoskeletal infection outside the spine. The objective of the White Paper was to critically assess the literature and propose standardized terminology for imaging findings of infection on MRI, in order to improve both communication with clinical colleagues and patient care.A definition was proposed for each term; debate followed, and the committee reached consensus. Potential controversies were raised, with formulated recommendations. The committee arrived at consensus definitions for cellulitis, soft tissue abscess, and necrotizing infection, while discouraging the nonspecific term phlegmon. For bone infection, the term osteitis is not useful; the panel recommends using terms that describe the likelihood of osteomyelitis in cases where definitive signal changes are lacking. The work was presented virtually to SSR members, who had the opportunity for review and modification prior to submission for publication.

The Evolving Roles of MRI and Ultrasound in First-Line Imaging of Rotator Cuff Injuries.

Rotator cuff tears are the most likely source of shoulder pain in adults and may cause protracted disability. Management of rotator cuff tears is associated with considerable costs. Accurate diagnosis can guide surgical planning and help achieve a favorable clinical outcome. Although radiography remains the initial imaging test for shoulder injury, the roles of MRI and ultrasound (US) as first-line imaging after radiography are evolving. This article leverages current literature and the practical experience of subspecialty musculoskeletal radiologists from different institutions in describing a practical approach to imaging rotator cuff pathology. Both MRI and US are accurate for identifying rotator cuff tears, but each has advantages and shortcomings. As both modalities currently represent reasonable first-line approaches, considerable practice variation has evolved. Given the low cost of US, imagers should strive to optimize the quality of shoulder US examinations and to build referrer confidence in this modality. The roles of direct CT and MR arthrography as well as imaging evaluation of the postoperative rotator cuff are also considered. Through careful selection among the available imaging modalities and optimal performance and interpretation of such examinations, radiologists can positively contribute to the diagnosis and treatment of patients with rotator cuff injuries.

Extensor mechanism tendinopathy in patients with lateral patellar maltracking.

OBJECTIVE: Patellar maltracking is an important subset of patellofemoral pain syndrome. We hypothesize that maltracking patients have an increased incidence of extensor mechanism dysfunction due to repetitive attempts at stabilization of the patella. Our purpose is to delineate imaging features to identify maltracking patients at risk for extensor mechanism tendinopathy. MATERIALS AND METHODS: Retrospective review of knee MRIs performed for anterior knee pain over a year was conducted to identify 218 studies with imaging findings of maltracking. The cases were evaluated for the presence and degree of patellar and quadriceps tendinopathy, tibial tuberosity-trochlear groove distance (TT-TG) and the distribution and grade of patellofemoral chondrosis. Cases were compared to 100 healthy, age-matched control knee MRIs. RESULTS: The mean age of maltracking patients with either patellar or quadriceps tendinosis was 41.2 years versus 48.2 years in the control population (p = 0.037). The TT-TG was significantly higher in maltracking patients with either patellar or quadriceps tendinosis at 16.49 mm versus 14.99 mm (p = 0.006). Maltrackers with isolated lateral patellofemoral chondrosis had a higher mean TT-TG at 17.4 mm versus 15.4 mm (p = 0.007). Extensor mechanism tendinosis was increased in the maltracking population compared to the controls at 57.8% versus 27.3% (p = 0.004). CONCLUSION: Extensor mechanism tendinosis is more common in the maltracking population and occurs at a younger age. TT-TG distance is significantly increased in patients with extensor mechanism dysfunction and in patients with isolated lateral patellofemoral chondrosis. TT-TG measurement can be used independently to identifying maltrackers who may be at risk for future complications.

Prevalence of lateral patellofemoral maltracking and associated complications in patients with Osgood Schlatter disease.

OBJECTIVE: To evaluate adults with history of Osgood Schlatter disease (OSD) for imaging features of lateral patellofemoral maltracking. METHODS: In a span of four years, 10,181 unique non-contrast knee MRIs were performed on patients aged 20-50. Patients with acute trauma, prior surgery, and synovial pathologies were excluded. 171 exams had imaging findings of OSD, and an age-matched control group of 342 patients without OSD was randomly selected. Two radiologists retrospectively reviewed MRIs for features of lateral patellofemoral maltracking. Maltracking was defined as edema in superolateral Hoffa's fat or a tibial tuberosity-trochlear groove (TT-TG) distance ≥20 mm with either patellar tilt/translation. Binomial logistic regression identified predictors of maltracking in OSD. Optimal TT-TG distance to indicate maltracking was determined by receiver operating characteristic curve. RESULTS: 59% (101/171) of the knees with OSD showed findings of maltracking, with patella alta, trochlear dysplasia, and quadriceps tendinosis as significant predictors of maltracking (p < 0.001). Patellofemoral chondrosis was present in 63% (107/171), with maltracking contributing to higher grade chondrosis more so than increasing age (OR 8.4 versus 1.07). 13 mm was the optimal cut-off TT-TG distance to indicate maltracking (sensitivity 83%, specificity 80%). The prevalence of maltracking in the control group was 15% (p < 0.001 compared with the OSD group). CONCLUSION: Adults with sequelae of OSD are at high risk of maltracking and are likely to develop patellofemoral chondrosis. A lower threshold for identifying maltracking patients, including a lower cut-off TT-TG distance can help identify those at risk. Radiologists should maintain a high index of suspicion for maltracking in adults with OSD to guide clinical intervention.

Lateral femoral condyle insufficiency fractures: imaging findings, demographics, and analysis of outcomes.

OBJECTIVE: To describe imaging characteristics and demographics of lateral femoral condyle insufficiency fractures (LFCIFs) and identify characteristics associated with progression to epiphyseal collapse. MATERIALS AND METHODS: A retrospective review of 105 consecutive patients with LFCIF was performed (mean age 58.1 years) after excluding post-traumatic and pathological fractures. Lesion size and location, presence of bone marrow edema-like signal, soft tissue edema, chondrosis grade, and meniscus pathology were documented. Demographics were recorded from the electronic patient record. Follow-up MRI and/or radiographs were evaluated for healing/stability or progression to epiphyseal collapse. Bone mineral density was assessed from dual-energy x-ray absorptiometry (DEXA) scans and/or radiographs. RESULTS: Fifty-six female and 49 male subjects were included. Female subjects were older at presentation (60.5 versus 56.3 years, p = .02). A total of 61.7% of the subjects with available DEXA and/or radiographs had osteopenia/osteoporosis. The central weight-bearing (61%) and outer condyle (54.3%) were most involved. High-grade chondrosis was present in ≥ 1 compartment in 70.5% including 42% in the lateral compartment. A total of 67.6% had ≥ 1 meniscus tear with similar frequency of medial and lateral tears (47.6% versus 41%). Bone marrow edema-like signal was present in all cases; soft tissue edema was present in 83.8%. Fifty-three subjects had available follow-up MRI (n = 24) and/or radiographs (n = 29). Increased age, fracture dimensions, presence of medial meniscus tears, and high-grade patellofemoral chondrosis were associated with progression (p ≤ .05). CONCLUSION: LFCIFs are associated with meniscus tears, high-grade chondrosis, and osteopenia/osteoporosis with more global knee pathology present when compared with medial femoral condyle insufficiency fracture. Increased age, medial meniscus tears, fracture dimensions, and high-grade patellofemoral chondrosis were associated with progression.

The Relationship Between Discoid Meniscus and Articular Cartilage Thickness: A Quantitative Observational Study With MRI.

BACKGROUND: Several cadaveric imaging studies have demonstrated that the articular cartilage thickness on the tibial plateau varies depending on coverage by native meniscal tissue. These differences are thought to partially contribute to the rates of cartilage degeneration and development of osteoarthritis after meniscectomy. Because there is greater tibial plateau coverage with meniscal tissue in the setting of a discoid meniscus, these findings may also have implications for the long-term health of the knee after saucerization of a torn discoid meniscus. PURPOSE: To evaluate the relationship between lateral compartment articular cartilage thickness and the presence or absence of a discoid meniscus. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Included in the study were 25 patients younger than 40 years of age who had undergone a 1.5-T or 3-T knee magnetic resonance imaging (MRI) between 2010 and 2016 at a single institution and had an intact, lateral discoid meniscus. Only patients with an otherwise asymptomatic lateral compartment were included. The authors then identified 35 age-matched controls with a nondiscoid, intact lateral meniscus who underwent knee MRI at the same institution and during the same period. The articular cartilage thicknesses in 6 zones of the lateral femoral condyle (LFC) and lateral tibial plateau (LTP) were measured for each patient by 2 musculoskeletal radiologists, and the mean thicknesses were compared between the study and control groups. RESULTS: The average age at MRI was 22.63 years (range, 8.30-35.90 years) for the discoid group and 20.93 years (range, 8.43-34.99 years) for the nondiscoid group. The nondiscoid group had significantly greater mean articular cartilage thickness in all 6 zones of the LTP (P < .05 for all). When comparing the zones of the LFC, there was no significant difference in the mean thickness in any zone between the 2 groups. CONCLUSION: Patients with discoid menisci had thinner baseline articular cartilage thickness in the LTP compared with those patients without discoid menisci.

Painful type II os naviculare: introduction of a standardized, reproducible classification system.

OBJECTIVE: To provide a novel MRI classification system for the symptomatic type II os naviculare by creating a standardized grading of associated bone marrow edema (BME) and correlating with patient symptoms. METHODS: BME was classified on an ordinal scale: grade 1, faint signal immediately adjacent to the synchondrosis; grade 2, intermediate signal within the os and navicular tuberosity without extending to the navicular body; grade 3, intense signal extending to the navicular body. BME on 59 MRIs was independently graded by three radiologists. Inter- and intra-observer agreement was analyzed using intraclass correlation coefficient. Univariate and multivariate analyses assessed for patient and imaging characteristics predictive of subjective pain score. A cohort of 82 patients without BME represented a control group. RESULTS: Inter-observer agreement of BME grade was 0.95 (CI 0.93-0.97) and intra-observer was 0.92 (CI 0.87-0.96), indicating excellent agreement. In patients with BME, predictors of more severe pain were longer duration of pain (p = 0.02) and presence of soft tissue edema overlying the os naviculare (p < 0.001). One hundred percent of subjects with BME localized their pain to the medial midfoot (59/59) versus 25.6% (21/82) of controls (p < 0.001). CONCLUSIONS: This novel grading system provides reliable quantification of BME associated with os naviculare, which is a specific cause of medial foot/ankle pain. Early diagnosis is important as pain severity worsens with longer duration of symptoms. Pain severity is correlated with soft tissue edema overlying the os, which may be secondary to extrinsic compression, reactive to biomechanical stress, or reflect direct trauma.