Faculty Bibliography

INTRODUCTION/BACKGROUND:Peroneal nerve injuries are rare injuries and usually associated with multiligamentous knee injuries (MLKIs) involving one or both cruciate ligaments. The purpose of our study was to perform a multicenter retrospective cohort analysis to examine the rates of peroneal nerve injuries and to see whether a peroneal nerve injury was suggestive of a particular injury pattern. METHODS:A retrospective chart review was conducted in patients who were diagnosed with MLKI at two level I trauma centers from January 2001 to March 2021. MLKIs were defined as complete injuries to two or more knee ligaments that required surgical reconstruction or repair. Peroneal nerve injury was clinically diagnosed in these patients by the attending orthopaedic surgeon. Radiographs, advanced imaging, and surgical characteristics were obtained through a chart review. RESULTS:Overall, 221 patients were included in this study. The mean age was 35.9 years, and 72.9% of the population was male. Overall, the incidence of clinical peroneal nerve injury was 19.5% (43 patients). One hundred percent of the patients with peroneal nerve injury had a posterolateral corner injury. Among patients with peroneal nerve injury, 95.3% had a complete anterior cruciate ligament (ACL) rupture as compared with 4.7% of the patients who presented with an intact ACL. There was 4.4 times of greater relative risk of peroneal nerve injury in the MLKI with ACL tear group compared with the MLKI without an ACL tear group. No statistical difference was observed in age, sex, or body mass index between patients experiencing peroneal nerve injuries and those who did not. CONCLUSION/CONCLUSIONS:The rate of ACL involvement in patients presenting with a traumatic peroneal nerve palsy is exceptionally high, whereas the chance of having a spared ACL is exceptionally low. More than 90% of the patients presenting with a nerve palsy will have sustained, at the least, an ACL and posterolateral corner injury. LEVEL OF EVIDENCE/METHODS:IV, Case Series.

Background/UNASSIGNED:Peroneal nerve (PN) palsy is one of the most debilitating sequelae of multiligamentous knee injuries (MLKIs). There is limited research on recovery from complete PN palsy. Purpose/Hypothesis/UNASSIGNED:The purpose of this study was to characterize PN injuries and develop a predictive model of complete PN recovery after MLKI using machine learning. It was hypothesized that elevated body mass index (BMI) would be predictive of lower likelihood of recovery. Study Design/UNASSIGNED:Case-control study; Level of evidence, 3. Methods/UNASSIGNED:The authors conducted a retrospective review of patients seen at 2 urban hospital systems for treatment of MLKI with associated complete PN palsy, defined as the presence of complete foot drop with or without sensory deficits on physical examination. Recovery was defined as the complete resolution of foot drop. A random forest (RF) classifier algorithm was used to identify demographic, injury, treatment, and postoperative variables that were significant predictors of recovery from complete PN palsy. Validity of the RF model was assessed using overall accuracy, F1 score, and area under the receiver operating characteristic curve (AUC). Results/UNASSIGNED:Overall, 16 patients with MLKI with associated complete PN palsy were included in the cohort. Among them, 75% (12/16) had documented knee dislocation requiring reduction. Complete recovery occurred in 4 patients (25%). Nerve contusions on magnetic resonance imaging were more common among patients without PN recovery, but there were no other significant differences between recovery and nonrecovery groups. The RF model found that older age, increasing BMI, and male sex were predictive of worse likelihood of PN recovery. The model was found to have good validity, with a classification accuracy of 75%, F1 score of 0.86, and AUC of 0.64. Conclusion/UNASSIGNED:The RF model in this study found that increasing age, BMI, and male sex were predictive of decreased likelihood of nerve recovery. While further study of machine learning models with larger patient data sets is required to identify the most superior model, these findings present an opportunity for orthopaedic surgeons to better identify, counsel, and treat patients with MLKIs and concomitant complete PN palsy.

PURPOSE/OBJECTIVE:The purpose of this study was to evaluate the mid-term results of posterior medial meniscal root tear (PMMRT) repair through assessment of functional outcome scores and magnetic resonance imaging (MRI). METHODS:This was a single-center, retrospective study evaluating patients that had undergone a PMMRT. This was a follow-up to a previously published 2-year outcome study (all original patients were invited to participate). Clinical outcomes included pre- and postoperative International Knee Documentation Committee (IKDC) and Lysholm scores. Root healing, meniscal extrusion, and cartilage degeneration via International Cartilage Repair Society Scale (ICRS) grades were assessed on MRI by two musculoskeletal fellowship-trained radiologists. RESULTS:10 of the original study's 18 patients were able to participate. Mean age and BMI was 48.4 ± 12.0 years and 29.5 ± 4.5, respectively, with mean follow-up 65.5 ± 8.3 months (range 52.0-75.8) (60% female). The IKDC significantly increased from 43 ± 13 preoperatively to 75 ± 16 at 5-year follow-up (p < 0.001). There was no significant change in IKDC score between 2-year and 5-year follow-up [75 ± 16 vs 73 ± 20, (n.s)]. The Lysholm also significantly increased between preoperative and 5-year follow-up (49 ± 7 vs 84 ± 11, p < 0.001). There was no significant change between Lysholm score at 2-year and 5-year follow-up [84.0 ± 11 vs 82 ± 13, (n.s)]. Mean extrusion did not significantly change from the preoperative state to 5-year follow-up [4.80 mm ± 1.9 vs 5.0 mm ± 2.5, (n.s.)]. Extrusion also did not significantly change between 2-and 5-year follow-up [6.1 ± 3.2 mm vs 5.0 mm ± 2.5, (n.s.)]. No patients with > 3 mm of extrusion on preoperative MRI had < 3 mm of extrusion on postoperative MRI. Both medial femoral condyle and medial tibial plateau ICRS grades significantly increased from preoperative to 2-year follow-up (p = 0.038, p = 0.023, respectively). Medial femoral condyle and medial tibial plateau ICRS grades again significantly increased between 2-year and 5-year follow-up (p = 0.014, p = 0.034). CONCLUSION/CONCLUSIONS:Patients treated with the transtibial suture pullout technique with two locking cinch sutures had maintenance of clinical outcome improvements at 5-year follow-up. However, extrusion was widely prevalent, with worsening progression of femoral and tibial chondral disease. LEVEL OF EVIDENCE/METHODS:Level 4.

Purpose: To determine the safety and effectiveness of genicular artery embolization (GAE) in reducing knee pain in patients with mild to moderate knee osteoarthritis (OA), as measured by validated patient reported outcome measures, and to characterize pre/post-procedural trends in multiple OA-associated serum biomarkers
Material(s) and Method(s): In an ongoing, prospective, single-arm clinical trial, patients with mild to moderate (Kellgren-Lawrence grade 2-3) symptomatic knee OA, without prior surgery and who failed conservative therapy, were included. Pre-intervention imaging (plain radiographs and MRI), patient-reported outcome measures (KOOS, WOMAC, VAS), and serum biomarkers (IL-1Ra, CRP, Hyaluronan, COMP, VEGF, CCL2-MCP-1) were obtained. Each patient underwent transcatheter arterial embolization of one or more genicular arteries in the affected knee using 250-mum microspheres (Embozene, Varian). One- and three-month post-intervention patient-reported outcome measures and serum biomarkers were obtained. Baseline and follow-up outcomes were compared using paired Wilcoxon signed-rank tests.
Result(s): The first 7 patients (4 male, mean age 68 +/- 6y, mean BMI 30 +/- 2) recruited into this trial were included in this preliminary analysis. Technical success was 100%. There were no adverse events. By 3 months, VAS pain scores decreased from 56 to 21 (63% decrease); WOMAC pain scores decreased from 8 to 4 (50% decrease); and KOOS pain scores (for which higher scores indicate less pain) increased from 57 to 81 (42% increase), all P >0.05. Baseline and 3-month mean biomarker values were: IL-1Ra (471 +/- 276 vs 590 +/- 320 pg/mL), CRP (1.81 +/- 1.78 vs 3.24 +/- 4.25 mg/L), Hyaluronan (92 +/- 66 vs 166 +/- 102 ng/mL), COMP (942 +/- 336 vs 1057 +/- 462 ng/mL), VEGF (372 +/- 283 vs 303 +/- 101 pg/mL), and CCL2-MCP-1 (335 +/- 90 vs 323 +/- 69 pg/mL), all P >0.05.
Conclusion(s): Patient-reported pain scores demonstrated a trend in improvement 3 months after GAE at our interim analysis. There were no significant changes between baseline and 3-month follow-up in serum OA biomarkers in this small sample size. Full study analysis will further delineate trends in serum biomarkers after GAE.
Copyright

The posteromedial and posterolateral corners of the knee are important areas to consider when assessing the patient with a possible knee injury. An understanding of the anatomy, associated biomechanics, and typical injury patterns in these regions will improve the value that the radiologist interpreting the MRIs brings to this patient population.

Entrapment neuropathies of the shoulder most commonly involve the suprascapular or axillary nerves, and they primarily affect the younger, athletic patient population. The extremes of shoulder mobility required for competitive overhead athletes, particularly in the position of abduction and external rotation, place this cohort at particular risk. Anatomically, the suprascapular nerve is most prone to entrapment at the level of the suprascapular or spinoglenoid notch; the axillary nerve is most prone to entrapment as it traverses the confines of the quadrilateral space.Radiographs should be ordered as a primary imaging study to evaluate for obvious pathology occurring along the course of the nerves or for pathology predisposing the patient to nerve injury. Magnetic resonance imaging plays a role in not only identifying any mass-compressing lesion along the course of the nerve, but also in identifying muscle signal changes typical for denervation and/or fatty atrophy in the distribution of the involved nerve.

PURPOSE/OBJECTIVE:The purpose of this study was to identify if the location of posterolateral corner (PLC) injury was predictive of clinical common peroneal nerve (CPN) palsy. METHODS:A retrospective chart review was conducted of patients presenting to our institution with operative PLC injuries. Assessment of concomitant injuries and presence of neurologic injury was completed via chart review and magnetic resonance imaging (MRI) review. A fellowship-trained musculoskeletal radiologist reviewed the PLC injury and categorized it into distal, middle and proximal injuries with or without a biceps femoral avulsion. The CPN was evaluated for signs of displacement or neuritis. RESULTS:Forty-seven operatively managed patients between 2014 and 2019 (mean age-at-injury 29.5 ± 10.7 years) were included in this study. Eleven (23.4%) total patients presented with a clinical CPN palsy. Distal PLC injuries were significantly associated with CPN palsy [9 (81.8%) patients, (P = 0.041)]. Nine of 11 (81.8%) patients with CPN palsy had biceps femoral avulsion (P = 0.041). Of the patients presenting with CPN palsy, only four (36.4%) patients experienced complete neurologic recovery. Three of 7 patients (43%) with an intact CPN had full resolution of their clinically complete CPN palsy at the time of follow-up (482 ± 357 days). All patients presenting with a CPN palsy also had a complete anterior cruciate ligament (ACL) rupture in addition to a PLC injury (P = 0.009), with or without a posterior cruciate ligament (PCL) injury. No patient presenting with an isolated pattern of PCL-PLC injury (those without ACL tears) had a clinical CPN palsy. CONCLUSION/CONCLUSIONS:Distal PLC injuries have a strong association with clinical CPN palsy, with suboptimal resolution in the initial post-operative period. Specifically, the presence of a biceps femoris avulsion injury was highly associated with a clinical CPN palsy. Additionally, CPN palsy in the context of PLC injury has a strong association with concomitant ACL injury. Furthermore, the relative rates of involvement of the ACL vs. PCL suggest that specific injury mechanism may have an important role in CPN palsy. LEVEL OF EVIDENCE/METHODS:IV.

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.