MRI-based navigated cryosurgery of extra-abdominal desmoid tumors using skin fiducial markers: a case series of 15 cases.

BACKGROUND: Precision surgery is becoming increasingly important in the field of Orthopaedic Oncology. Image-guided percutaneous cryosurgery (CRA) has emerged as a valid treatment modality for extra-abdominal desmoid tumors (EDTs). To date, most CRA procedures use CT-based guidance which fails to properly characterize tumor segments. Computer-guided MRI navigation can address this issue however, the lack of a fixed landmark for registration remains a challenge. Successful CRA correlates directly with precision approaches facilitated by intraoperative imaging guidance. This is the first study that attempts to assess the feasibility and efficacy of a novel approach of using skin fiducial markers to overcome the challenge of a MRI-based navigation CRA for symptomatic or progressive EDTs. METHODS: In this retrospective study conducted between 2018 and 2020, 11 patients at a single center with symptomatic or progressive EDTs were treated with CRA using intraoperative MRI navigation. Fifteen cryosurgery procedures were performed, each adhering to a personalized pre-operative plan. Total tumor size, viable and non-viable portions pre- and post-operation, and SF-36 questionnaire evaluating subjective health were recorded. RESULTS: All CRAs demonstrated 100% adherence to the predetermined plan. Overall, tumor size decreased Median= -56.9% [-25.6, -72.4]) with a reduction in viable tissue, (Median= -80.4% [-53.3, -95.2]). Four patients required additional CRAs. Only one patient's tumor did not reduce in size. One patient suffered from local muscle necrosis. Pre-operation, the average physical and mental scores 41.6 [29.4, 43] and 26.3 [17.6, 40.9] respectively. Post-operation, the average physical and mental scores were 53.4[38, 59.7] and 38 [31.2, 52.7] respectively. CONCLUSION: These findings provide an early indication of the feasibility and efficacy of performing percutaneous cryosurgery using skin fiducial marker registration for MRI-computed navigation to treat EDTs safely. Larger cohorts and multicenter evaluations are needed to determine the efficacy of this technique.

Reliability of Cone Beam Weightbearing Computed Tomography Analysis of Total Ankle Arthroplasty Positioning and Comparison to Weightbearing X-Ray Measurements.

BACKGROUND: The current reference standard for postoperative evaluation of total ankle arthroplasty (TAA) positioning, weightbearing radiography (WBXR), is subject to technical bias. Weightbearing cone beam computed tomography (WBCT) enables visualization of the foot's complex 3-dimensional (3D) structure under standing load. To date, no WBCT-based system for TAA positioning has been validated. The purpose of this study was to (1) assess TAA positioning using WBCT 3D models and (2) evaluate the agreement levels between 2 raters and thus evaluate the intermethod reliability with respect to WBXR. METHODS: Fifty-five consecutive patients were retrospectively reviewed. Two raters independently created a 3D WBCT model using dedicated software and recorded the following measurements: α angle, tibiotalar surface angle (TSA), hindfoot angle (HFA), tibiotalar ratio (TTR), ß angle, γ angle, and Φ angle. Measurements were repeated 2 months apart in similar, independent fashion and compared to WBXR. Interobserver, intraobserver, and intermethod agreements were calculated. RESULTS: All 7 measurements showed good to excellent intraobserver and interobserver reliability (ICC 0.85-0.95). The intermethod (WBCT vs WBXR) agreement showed good agreement for the γ angle (ICC 0.79); moderate agreement levels for the α angle, TSA angle, ß angle, and TTR (ICC 0.68, 0.69, 0.70, and 0.69, respectively); poor agreement for the HFA (ICC 0.25); and negative agreement for the φ angle (ICC -0.2). CONCLUSION: Position analysis of TAA using WBCT demonstrated good to excellent interobserver and intraobserver agreement and can be reliably used. Additionally, a negative to moderate agreement between standard WBCT and standard WBXR was found. LEVEL OF EVIDENCE: Level III, retrospective study.

Axial rotation analysis in total ankle arthroplasty using weight-bearing computer tomography and three-dimensional modeling.

BACKGROUND: Post-operative alignment is the most critical indicator for a successful total ankle arthroplasty (TAA). Total ankle malrotation is associated with an increased risk for polyethylene wear and medial gutter pain. Currently, there is no consensus on the correct way to measure the alignment of the tibial and talar component rotations in the axial plane. In the current study, the post-operative analysis system was assessed using weight-bearing computer tomography and a three-dimensional (3D) model. The purpose of the study was to assess the inter-observer and intra-observer agreement of this system. MATERIAL AND METHOD: Four angles were measured by two raters independently in two separate readings: posterior tibial component rotation angle (PTIRA), posterior talar component rotation angle (PTARA), tibia talar component axial angle (TTAM), and tibial component to the second metatarsal angle (TMRA). Agreement analysis was quantified according to the interclass coefficient. RESULTS: Sixty TAAs across 60 patients were evaluated. A good inter-observer agreement and intra-observer agreement when measuring the PTIRA, PTARA, and TTAM angles was observed along with an excellent inter-observer agreement and intra-observer agreement when measuring the TMRA angle. CONCLUSION: In conclusion, the current 3D model-based measurement system demonstrates good to excellent inter and intra-agreement. According to these results, 3D modelling can be reliably used to measure and assess the axial rotation of TAA components. LEVEL OF EVIDENCE: Level 3 retrospective study.

Classification of the Os Calcis Subtalar Morphology in Symptomatic Flexible Pediatric Pes Planus Deformity Using Weightbearing CT and Distance Mapping.

BACKGROUND: The etiology of symptomatic pediatric pes planus (PP) deformity is unclear. Reduced os calcis subtalar joint (OCST) anterior facet morphology has been suggested to result in less support to the talar head and a higher propensity to develop PP deformity. Weightbearing computed tomography (WBCT) and distance mapping (DM) offer new opportunities to investigate PP deformity in general and the OCST specifically. The purpose of this study is to investigate the OCST morphology using DM and to classify PP subtalar subtypes with DM using Bruckner's A-D classification system. METHODS: Forty feet in 25 patients in a national referral center were evaluated for symptomatic PP deformity that failed nonoperative treatment. A WBCT scan was performed as part of the preoperative evaluation. Visualization of the distance distribution between the articulating surfaces of the subtalar joint was based on a DM technique. Intra- and interobserver agreement of the subtalar morphology was assessed using Bruckner's classification system. RESULTS: The mean age was 10.7 ± 1.4 years. The following mean ± SD and median ± ranges were semiautomatically measured for this group: Meary angle -21 ± 8, calcaneal inclination 15 ± 4 degrees, talar coverage angle 39 (range 32.6-49) degrees, and hindfoot moment-arm 16 ± 5 mm. Classifying subtalar morphology using DM yielded an excellent intra- and interobserver agreement. The individual percentages of each individual subtype were calculated: type A 5%, type B 48%, type C 4%, and type D in 44%. CONCLUSION: This study demonstrated excellent intraobserver and interobserver agreement in classifying the OCST using DM. A higher prevalence of types B and D was observed compared to types A and C in this PP cohort. LEVEL OF EVIDENCE: Level III, retrospective study.

Inhospital Complications and Costs of Simultaneous Bilateral Total Knee Arthroplasty: The Case for Selection and Potential Cost Savings.

BACKGROUND: Published comparisons between bilateral and unilateral total knee arthroplasties (TKAs) remain biased, as most patients undergoing bilateral TKA are prescreened and healthier than average patients having unilateral procedures. Our objectives were to compare postoperative complications and resource utilization of patients having simultaneous bilateral TKAs with similar patients having unilateral procedures. METHODS: The Nationwide Inpatient Sample (NIS) database was used to identify patients undergoing primary elective TKA from 2002 to 2011. A total of 4,445,263 patients were identified. Of these, 190,783 (4%) were having same-day bilateral procedures. Patients with staged bilateral TKA during the same hospitalization were excluded. Complications and costs were compared to a matched cohort of patients having unilateral procedures. This cohort was matched based on age, gender, and 30 comorbid-defined elements in the NIS. RESULTS: A total of 172,366 (90%) simultaneous bilateral procedures were matched 1:1 to patients with unilateral procedures for the adjusted analysis. Patients with bilateral procedures were at an increased risk for many complications including postoperative anemia (OR: 2.3; 95% CI: 2.2-2.3, P < .001), cardiac (OR: 2.1; 95% CI: 2.0-2.3, P < .001), and inhospital mortality (OR: 3.3; 95% CI: 2.6-4.3). These patients also incurred in higher hospital costs ($19,343 vs $12,852, P < .001) and were discharged more commonly to a rehabilitation facility (70% vs 32%, P < .001). CONCLUSION: Patients undergoing simultaneous bilateral TKA are at an increased risk of developing important postoperative complications and mortality compared with unilateral cases. These data highlight the importance of patient selection and optimization for bilateral TKA and potential cost savings.

Increased Morbidity With Diagnosis and Treatment of Pulmonary Embolism After Total Joint Arthroplasty: A Matched Control Analysis of 30,000 Patients.

BACKGROUND: Currently, the risks associated with the diagnosis of pulmonary embolism (PE) and subsequent treatment are not well known. The purpose of our study is to quantify the specific in-hospital complications and resource utilization of patients with PE following total joint arthroplasty when compared to a matched cohort. METHODS: The Nationwide Inpatient Sample database was used to identify patients undergoing primary hip and knee arthroplasty from January 1993 to December 2008. PE was determined using International Classification of Diseases, Ninth Revision, Clinical Modification codes. In-hospital complications, costs, and length of stay for patients with PE were compared to patients without PE, matched on the basis of age, gender, procedure (total hip arthroplasty vs total knee arthroplasty), year of surgery, morbid obesity, and all 28 comorbid-defined elements of the Elixhauser Comorbidity Index. RESULTS: Of 8,634,038 procedures, 30,281 (0.4%) patients had a PE after total joint arthroplasty. In total, 29,917 (98%) were matched one-to-one with patients without PE. Patients with PE had a substantially higher risk of all postoperative in-hospital complications: deep vein thrombosis (odds ratio [OR] 17), peripheral vascular (OR 34), hematoma (OR 3.7), and gastrointestinal bleeding (OR 7.0) (all P < .001). Mortality was significantly higher in patients with PE compared to patients without PE (3.4% vs 0.1%, OR 30), along with total hospital costs, lengths of stay, and rates of discharge to rehabilitation facilities. CONCLUSION: After controlling for comorbidities patients with PE have a significantly higher risk for complications including in-hospital mortality and higher hospital costs when compared to patient without PE.