Effect of sequential burr passes on osteotomy magnitude and calcaneal morphology in minimally invasive Zadek osteotomy.

PURPOSE: This study aimed to evaluate the impact of each burr pass on degree of correction, gap size and calcaneal morphology in MIS Zadek osteotomy. METHODS: MIS Zadek osteotomy was performed on ten cadaveric specimens using a 3.1 mm Shannon burr. After each burr pass, the osteotomy gap was manually closed, and the subsequent burr passes were carried out with the foot held in dorsiflexion, which was repeated five times. Lateral X-rays were taken before and after each burr pass. Two independent reviewers measured the dorsal calcaneal length after each burr passage, as well as changes in several calcaneal parameters including X/Y ratio, Fowler Philip angle, and Böhler angle. RESULTS: The average decrease in dorsal calcaneal cortical length with each burr pass was as follows: 2.6 ± 0.9 mm at the 1st pass, 2.4 ± 1 mm at the 2nd pass, 2 ± 1 mm at the 3rd pass, 1.6 ± 1 mm at the 4th pass, and 1.4 ± 0.7 mm at the 5th pass. The Fowler Philip and Böhler angles consistently decreased while the X/Y ratio consistently increased following each consecutive burr pass. Interobserver reliability analysis demonstrated good agreement for all parameters. CONCLUSION: The results revealed the trends of length and anatomical changes in the calcaneus with each burr pass. On average, a dorsal wedge resection of 10 mm was achieved after 5 burr passes. This data can aid surgeons in determining the optimal number of burr passes required for a particular amount of resection, ensuring the attainment of the desired patient-specific surgical outcome.

Effect of sequential burr passes on minimally invasive akin and first metatarsal dorsiflexion osteotomies.

BACKGROUND: Minimally invasive surgical (MIS) osteotomies are increasing as a surgical option for treating midfoot and forefoot conditions. This study aimed to evaluate the impact of each burr pass on the degree of correction, gap size, and alignment in MIS Akin and first metatarsal dorsiflexion osteotomies (DFO). METHODS: MIS Akin and first metatarsal DFO were performed on ten cadaveric specimens. Fluoroscopic measurements included the metatarsal dorsiflexion angle (MDA), dorsal cortical length (MDCL), first phalangeal medial cortical length (PCML) and proximal to distal phalangeal articular angle (PDPAA). RESULTS: The average decrease in PCML with each burr pass was as follows: 1.53, 1.33, 1.27, 1.23 and 1.13 mm at the 1st to 5th pass, respectively. The MDCL sequentially decreased by 1.80, 1.59, 1.35, 0.75, and 0.60 mm. The MDA consistently decreased, and the PDPAA incrementally became more valgus oriented. CONCLUSION: On average, a first metatarsal dorsal wedge resection of 4.7 mm and first phalangeal medial wedge resection of 2.9 mm was achieved after 3 and 2 burr passes, respectively. This data may aid surgeons determine the optimal number of burr passes required to achieve the desired patient-specific surgical correction.

Development of drug-inducible CRISPR-Cas9 systems for large-scale functional screening.

BACKGROUND: Large-scale genetic screening using CRISPR-Cas9 technology has emerged as a powerful approach to uncover and validate gene functions. The ability to control the timing of genetic perturbation during CRISPR screens will facilitate precise dissection of dynamic and complex biological processes. Here, we report the optimization of a drug-inducible CRISPR-Cas9 system that allows high-throughput gene interrogation with a temporal control. RESULTS: We designed multiple drug-inducible sgRNA expression vectors and measured their activities using an EGFP gene disruption assay in 11 human and mouse cell lines. The optimal design allows for a tight and inducible control of gene knockout in vitro, and in vivo during a seven-week-long experiment following hematopoietic reconstitution in mice. We next performed parallel genome-wide loss-of-function screens using the inducible and constitutive CRISPR-Cas9 systems. In proliferation-based dropout screens, these two approaches have similar performance in discriminating essential and nonessential genes. In a more challenging phenotypic assay that requires cytokine stimulation and cell staining, we observed similar sensitivity of the constitutive and drug-induced screening approaches in detecting known hits. Importantly, we demonstrate minimal leakiness of our inducible CRISPR screening platforms in the absence of chemical inducers in large-scale settings. CONCLUSIONS: In this study, we have developed a drug-inducible CRISPR-Cas9 system that shows high cleavage efficiency upon induction but low background activity. Using this system, we have achieved inducible gene disruption in a wide range of cell types both in vitro and in vivo. For the first time, we present a systematic side-by-side comparison of constitutive and drug-inducible CRISPR-Cas9 platforms in large-scale functional screens. We demonstrate the tightness and efficiency of our drug-inducible CRISPR-Cas9 system in genome-wide pooled screening. Our design increases the versatility of CRISPR-based genetic screening and represents a significant upgrade on existing functional genomics toolbox.

A Distributed Network for Intensive Longitudinal Monitoring in Metastatic Triple-Negative Breast Cancer.

Accelerating cancer research is expected to require new types of clinical trials. This report describes the Intensive Trial of OMics in Cancer (ITOMIC) and a participant with triple-negative breast cancer metastatic to bone, who had markedly elevated circulating tumor cells (CTCs) that were monitored 48 times over 9 months. A total of 32 researchers from 14 institutions were engaged in the patient's evaluation; 20 researchers had no prior involvement in patient care and 18 were recruited specifically for this patient. Whole-exome sequencing of 3 bone marrow samples demonstrated a novel ROS1 variant that was estimated to be present in most or all tumor cells. After an initial response to cisplatin, a hypothesis of crizotinib sensitivity was disproven. Leukapheresis followed by partial CTC enrichment allowed for the development of a differential high-throughput drug screen and demonstrated sensitivity to investigational BH3-mimetic inhibitors of BCL-2 that could not be tested in the patient because requests to the pharmaceutical sponsors were denied. The number and size of CTC clusters correlated with clinical status and eventually death. Focusing the expertise of a distributed network of investigators on an intensively monitored patient with cancer can generate high-resolution views of the natural history of cancer and suggest new opportunities for therapy. Optimization requires access to investigational drugs.

Morbidity and readmission after open reduction and internal fixation of ankle fractures are associated with preoperative patient characteristics.

BACKGROUND: Ankle fractures are common and can be associated with severe morbidity. Risk factors for short-term adverse events and readmission after open reduction and internal fixation (ORIF) of ankle fractures have not been fully characterized. QUESTIONS/PURPOSES: The purpose of our study was to determine patient rates and risk factors for (1) any adverse event; (2) severe adverse events; (3) infectious complications; and (4) readmission after ORIF of ankle fractures. METHODS: Patients who underwent ORIF for ankle fracture from 2005 to 2012 were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP(®)) database using International Classification of Diseases, 9(th) Revision and Current Procedural Terminology codes. Patients with missing perioperative data were excluded from this study. Patient characteristics were tested for association with any adverse event, severe adverse events, infectious complications, and readmission using bivariate and multivariate logistic regression analyses. RESULTS: Of the 4412 patients identified, 5% had an adverse event. Any adverse event was associated with insulin-dependent diabetes mellitus (IDDM; odds ratio [OR], 2.05; 95% confidence interval [CI], 1.35-3.1; p = 0.001), age ≥ 60 years (OR, 1.97; 95% CI, 1.22-3.2; p = 0.006), American Society of Anesthesiologists classification ≥ 3 (OR, 1.69; 95% CI, 1.2-2.37; p = 0.002), bimalleolar fracture (OR, 1.6; 95% CI, 1.08-2.37; p = 0.020), hypertension (OR, 1.47; 95% CI, 1.04-2.09; p = 0.031), and dependent functional status (OR, 1.47; 95% CI, 1.02-2.14; p = 0.040) on multivariate analysis. Severe adverse events occurred in 3.56% and were associated with ASA classification ≥ 3 (OR, 2.01; p = 0.001), pulmonary disease (OR, 1.9; p = 0.004), dependent functional status (OR, 1.8; p = 0.005), and hypertension (OR, 1.65; p = 0.021). Infectious complications occurred in 1.75% and were associated with IDDM (OR, 3.51; p < 0.001), dependent functional status (OR, 2.4; p = 0.002), age ≥ 60 years (OR, 2.28; p = 0.028), and bimalleolar fracture (OR, 2.19; p = 0.030). Readmission occurred in 3.17% and was associated with ASA classification ≥ 3 (OR, 2.01; p = 0.017). CONCLUSIONS: IDDM was associated with an increased rate of adverse events after ankle fracture ORIF, whereas noninsulin-dependent diabetes mellitus was not. IDDM management deserves future study, particularly with respect to glycemic control, a potential confounder that could not be assessed with the ACS-NSQIP registry. Increased ASA class was associated with readmission, and future prospective investigations should evaluate the effectiveness of increasing the discharge threshold, discharging to extended-care facilities, and/or home nursing evaluations in this at-risk population. LEVEL OF EVIDENCE: Level III, prognostic study.

Factors Associated with the Transfer of Pediatric Patients with Supracondylar Humerus Fractures to a Level I Pediatric Trauma Center.

OBJECTIVE: To compare the characteristics of pediatric patients with supracondylar humerus fractures transferred to a level I pediatric trauma center to those who presented directly to our institution. METHODS: Retrospective chart review of patients with a supracondylar humerus fracture during a 42-month period (2008-2011) at a major level I pediatric trauma center were reviewed. Of 195 patients, 37 were transferred from outside hospitals. RESULTS: After multivariable analysis, it was determined that transferred patients were significantly more likely to present on the weekends (p = 0.003) and require operative treatment (p < 0.001) as compared to nontransferred patients. CONCLUSIONS: Injuries requiring operative treatment and presentation on a weekend were independent predictors of the transfer of pediatric patients with supracondylar humerus fractures.

Minimally Invasive vs Open Approach for First Metatarsophalangeal Joint Arthrodesis: Short Report of Early Results.

BACKGROUND: We aim to compare early surgical results between groups who underwent minimally invasive surgery (MIS) vs open first metatarsophalangeal (MTP) arthrodesis to treat end-stage hallux rigidus. METHODS: We conducted a retrospective cohort review of 65 patients who underwent a first MTP fusion procedure at an academic medical center between 2015 and 2023. Success of fusion was determined radiographically. Postoperative complications were identified through medical record review. RESULTS: Sixty-seven first MTP fusion surgeries (41 open and 26 MIS) were performed on 65 patients with a primary diagnosis of hallux rigidus. Open surgery and MIS groups had similarly high fusion rates: 95% (39/41) and 96% (25/26), respectively (P = .84). We identified no difference in overall complication rates: 20% for open surgery and 23% for MIS (P = .73). CONCLUSION: This retrospective analysis of 67 first MTP arthrodesis procedures showed no significant differences in fusion success or complications in the short term when comparing MIS to open surgery. Further studies are needed to elucidate potential differences between MIS vs open surgery. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Minimally Invasive Foot and Ankle Surgery: A Primer for Orthopaedic Surgeons.

There is rapidly growing interest in minimally invasive surgery (MIS) of the foot and ankle. Technological advances, specifically with the advent of low-speed high-torque burrs, have enabled the expansion of MIS techniques. Accordingly, there is growing literature reporting excellent outcomes of MIS surgery to address many different pathologies of the foot and ankle. MIS techniques are particularly useful for conducting percutaneous osteotomies and bony débridement. These can be used to address bunion deformity, hammertoes, metatarsalgia, bunionette deformity, bone spurs, and hindfoot deformity. A detailed understanding of the technology, equipment, and techniques is crucial to safely conduct MIS of the foot and ankle. When done safely, MIS provides favorable outcomes with an expedited recovery and limited complications.

Achilles Rupture in the Setting Posterior Tibial Osteochondroma: A Case Report and Guidelines for Management of Osteochondromas Adjacent to Tendons.

Introduction: The presentation of the included patient is unique, and the thought process regarding management algorithms used to manage this patient is important to discuss so that other surgeons may benefit. This is the first report of its kind, to our knowledge. Case Report: A 30-year-old healthy Caucasian male presented with acute Achilles tendon rupture after feeling a pop while playing basketball, in the setting of a known posterior tibial osteochondroma and a recent increase in physical activity. Conclusion: The resultant injury is likely due to mechanical irritation at the tendon site, which caused wear over time and eventual acute rupture. We expanded our percutaneous repair to include an evaluation of the posterior compartment to adequately visualize and excise the large bony lesion. Therefore, we conclude that it is reasonable to counsel patients with known osteochondromas in this location due to the risk of possible Achilles injury, particularly if at all symptomatic.

Immunohistochemical Detection of 5T4 in Renal Cell Carcinoma.

5T4 (trophoblast glycoprotein encoded by TPBG ) is a cancer/testis antigen highly expressed in renal cell carcinoma (RCC) and many other cancers but rarely in normal tissues. Interest in developing 5T4 as a prognostic biomarker and direct targeting of 5T4 by emerging receptor-engineered cellular immunotherapies has been hampered by the lack of validated 5T4-specific reagents for immunohistochemistry (IHC). We tested 4 commercially available monoclonal antibodies (mAbs) for the detection of 5T4 in formalin-fixed, paraffin-embedded RCC and normal tissues. Using parental and TPBG -edited A498 cells, 3 mAbs showed 5T4 specificity. Further analyses focused on 2 mAbs with the most robust staining (MBS1750093, Ab134162). IHC on tissue microarrays incorporating 263 renal tumors showed high staining concordance of these 2 mAbs ranging from 0.80 in chromophobe RCC to 0.89 in advanced clear cell RCC (ccRCC). MBS1750093, the most sensitive, exhibited 2+/3+ staining in papillary RCC (92.2%) > advanced ccRCC (60.0%) > chromophobe RCC (43.6%) > localized ccRCC (39.6%) > oncocytoma (22.7%). RNA in situ hybridization also revealed high levels of TPBG RNA were present most frequently in papillary and advanced ccRCC. In advanced ccRCC, there was a trend towards higher 5T4 expression and regional or distant metastases. Normal organ controls showed no or weak staining with the exception of focal moderate staining in kidney glomeruli and distal tubules by IHC. These data identify mAbs suitable for detecting 5T4 in formalin-fixed, paraffin-embedded tissues and demonstrate both interpatient and histologic subtype heterogeneity. Our validated 5T4 IHC protocol will facilitate biomarker studies and support the therapeutic targeting of 5T4.

The Fate of Delayed Unions After Isolated Ankle Fusion.

BACKGROUND: Nonunion remains the most common major complication of ankle arthrodesis. Although previous studies have reported delayed union or nonunion rates, few have elaborated on the clinical course of patients experiencing delayed union. In this retrospective cohort study, we sought to understand the trajectory of patients with delayed union by determining the rate of clinical success and failure and whether the extent of fusion on computed tomography scan (CT) was associated with outcomes. METHODS: Delayed union was defined as incomplete (<75%) fusion on CT between 2 and 6 months postoperatively. Thirty-six patients met the inclusion criterion: isolated tibiotalar arthrodesis with delayed union. Patient-reported outcomes were obtained including patient satisfaction with their fusion. Success was defined as patients who were not revised and reported satisfaction. Failure was defined as patients who required revision or reported being not satisfied. Fusion was assessed by measuring the percentage of osseous bridging across the joint on CT. The extent of fusion was categorized as absent (0%-24%), minimal (25%-49%), or moderate (50%-74%). RESULTS: We determined the clinical outcome of 28 (78%) patients with mean follow-up of 5.6 years (range, 1.3-10.2). The majority (71%) of patients failed. On average, CT scans were obtained 4 months after attempted ankle fusion. Patients with minimal or moderate fusion were more likely to succeed clinically than those with "absent" fusion (P = .040). Of those with absent fusion, 11 of 12 (92%) failed. In patients with minimal or moderate fusion, 9 of 16 (56%) failed. CONCLUSION: We found that 71% of patients with a delayed union at roughly 4 months after ankle fusion required revision or were not satisfied. Patients with less than 25% fusion on CT had an even lower rate of clinical success. These findings may help surgeons in counseling and managing patients experiencing a delayed union after ankle fusion. LEVEL OF EVIDENCE: Level IV, retrospective cohort study.

Diagnosis and Treatment of Neuropathic Ankle Fractures.

¼: Standard 3-view ankle radiographs are the first-line imaging modality for suspected neuropathic ankle fractures. Computed tomography is helpful to evaluate for concomitant osseous changes and soft-tissue infection. ¼: Nonoperative management may be considered for low-demand, elderly, or comorbid patients for whom surgery and anesthesia are contraindicated. However, the presence of comorbidities alone should not necessarily preclude operative intervention. Given the overall poor results of nonoperative treatment in the neuropathic ankle fracture population, operative intervention may in fact be less risky to the patient. ¼: The authors have 2 preferred treatment techniques. For cases in which the vascular supply and bone stock are adequate, open reduction and internal fixation (ORIF) with locking fixation for the fibula, a medial buttress/hook plate with lag screws for the medial malleolus, multiple syndesmotic screws for additional fixation even in the absence of a syndesmotic injury, and temporary transfixation Steinmann pins from the calcaneus into the tibia are used. For cases in which there is a concern for wound healing or previously failed ORIF, minimally invasive surgical tibiotalocalcaneal arthrodesis with a retrograde locked intramedullary nail is used.

Are SER-II Ankle Fractures Anatomic? Computed Tomography Demonstrates Mortise Malalignment in the Setting of Apparently Normal Radiographs.

BACKGROUND: Ankle fracture treatment is predicated on minimal displacement, leading to abnormal joint contact area. The purpose of this investigation is to determine whether computed tomography (CT) detects subtle mortise malalignment undetectable by x-ray in supination-external rotation-II (SER-II) injuries. METHODS: A total of 24 patients with SER-II injuries, as demonstrated by negative gravity stress radiography, were included. Medial clear space (MCS) measurements were performed on bilateral ankle x-rays (injured and contralateral, uninjured side) at several time points as well as bilateral non-weight-bearing CT performed once clinical and radiographic healing was demonstrated (mean = 66 days post injury, range = 61-105 days). Statistical analyses examined differences in measurements between both sides. RESULTS: Final x-rays demonstrated no differences between normal and injured ankle MCS (P = .441). However, CT coronal/axial MCS measurements were different (P < .05). CT coronal MCS measured wider by a mean difference of 0.67 mm (P < .001). CONCLUSION: There is a high incidence of subtle mortise malalignment in SER-II ankle fractures, as demonstrated by CT, which is undetectable when assessed by plain radiographs. Although clinical outcomes are yet unknown, there are important implications of the finding of confirmed, subtle mortise malalignment in SER-II injuries and the limitations of x-ray to detect it. LEVEL OF EVIDENCE: Level III.

Quality of MIS vs Open Joint Preparations of the Foot and Ankle.

BACKGROUND: Minimally invasive surgery (MIS) is growing in the field of foot and ankle, and the MIS burr is an emerging tool. Although commonly used to perform osteotomies, the burr can also be used for arthrodesis joint preparation that traditionally would be performed through open incisions. To date, there is no study comparing the quality of joint preparation between using a fluoroscopy-guided MIS technique compared to traditional open techniques. The goal of this cadaveric study is to compare the percentage of joint surfaces prepared between MIS and open techniques for the most common joints that are fused in foot and ankle surgery. METHODS: Open joint preparation was performed under direct visualization with open incisions. MIS joint preparation was performed percutaneously using fluoroscopic guidance alone, without arthroscopy. After joint preparation, cadaveric samples were disarticulated, and joint surfaces were analyzed for percentage of cartilaginous surface removed. The percentage of joint surface prepared was compared between the open and MIS techniques. RESULTS: Ten cadaveric samples were used for the MIS technique and 5 samples for the open technique. Percentage of joint surface prepared was similar for all joint surfaces. CONCLUSION: The MIS technique in the hands of experienced surgeons was found to provide overall similar percentages of surface area prepared compared to traditional open techniques. CLINICAL RELEVANCE: MIS joint preparation may be useful for specific patient populations. This study suggests that MIS joint preparation is a reasonable, and possibly advantageous, alternative to open preparation in arthrodesis surgery when performed by experienced MIS surgeons.

Syndesmotic Screw Breakage May Be More Problematic Than Previously Reported: Increased Rates of Hardware Removal Secondary to Pain With Intraosseous Screw Breakage.

BACKGROUND: The majority of retained syndesmotic screws will either loosen or break once the patient resumes weight-bearing. While evidence is limited, anecdotal experience suggests that intraosseous screw breakage may be problematic for some patients due to painful bony erosion. This study seeks to identify the incidence of intraosseous screw breakage, variables that may predict intraosseous screw breakage, and whether intraosseous screw breakage is associated with higher rates of implant removal secondary to pain. METHODS: Five hundred thirty-one patients undergoing syndesmotic stabilization were screened, of which 43 patients (with 58 screws) experiencing postoperative screw breakage met inclusion criteria. Patient charts were retrospectively reviewed for demographic data, comorbidities, time to screw breakage, location of screw breakage, and implant removal. Several radiographic parameters were evaluated for their potential to influence the site of screw breakage. RESULTS: Intraosseous screw breakage occurred in 32 patients (74.4%). Screw breakage occurred exclusively in the tibiofibular clear space in the remaining 11 instances (25.6%). Intraosseous screw breakage was significantly associated with eventual implant removal after breakage (P = .034). Screws placed further from the tibiotalar joint were at less risk for intraosseous breakage (odds ratio 0.818, P = .002). Screws placed at a threshold height of 20 mm or greater were more likely to break in the clear space (odds ratio 12.1, P = .002). CONCLUSION: Syndesmotic screw breakage may be more problematic than previously described. Intraosseous breakage was associated with higher rates of implant removal secondary to pain in this study. Placement of screws 20 mm or higher from the tibiotalar joint may decrease risk of intraosseous breakage.Levels of Evidence: Level III: Retrospective study.

Anatomic Structures at Risk During Posterior to Anterior Percutaneous Screw Fixation of Posterior Malleolar Fractures: A Cadaveric Study.

Background. There are no established guidelines for fixation of posterior malleolus fractures (PMFs). However, fixation of PMFs appears to be increasing with growing evidence demonstrating benefits for stability, alignment, and early functional outcomes. The purpose of this study was to determine the risk to anatomic structures utilizing a percutaneous technique for posterior to anterior (PA) screw fixation of PMFs. Methods. Percutaneous PA screw placement was carried out on 10 fresh frozen cadaveric ankles followed by dissection to identify soft tissue and neurovascular structures at risk. The distance from the guidewire to each anatomic structure of interest was measured. The correlation between the mean distances from the guidewire to each structure was calculated. Results. The sural nerve was directly transected in 1/10 specimens (10%) and in contact with the wire in a second specimen (10%). There was a significant correlation between the proximity of the guidewire to the apex of Volkmann's tubercle and its proximity to the sural nerve. The flexor hallucis longus (FHL) muscle belly was perforated by the guidewire 40% of the time but was not tethered or entrapped by the screw. Conclusions. Percutaneous PA screw placement is a safe technique which can be improved with several modifications. A mini-open technique is recommended to protect the sural nerve. There may be potential for tethering of the FHL with use of a washer or large screw head. Risk to the anterior and posterior neurovascular bundles is minimal.Levels of Evidence: Level V.

Peroneal Sheath Volumes Are Greater in Patients With Peroneal Pathology Compared With Controls.

BACKGROUND: Peroneal tendon pathology is common. Several factors have been implicated, including low-lying muscles and accessory tendons. Studies have reported on the presence and length measurements of these structures. This study evaluates volume measurements within the sheath using magnetic resonance images for patients with operatively treated peroneal tendon pathology and control patients without peroneal disease. METHODS: Fifty-one patients with peroneal tendon pathology and 15 controls were included. The volumes of the peroneal sheath, peroneal tendons, peroneal muscle, and accessory peroneus tendons were measured. The distal extent of the peroneus brevis (PB) muscle was measured. Volume and length measurements were then compared. RESULTS: The mean PB muscle length from the tip of the fibula was 5.55 ± 2.5 mm (peroneal group) and 11.79 ± 4.07 mm (control) (P = .017). The mean peroneal sheath volume was 7.06 versus 5.12 mL, respectively (P = .001). The major contributors to this increased volume was the tenosynovitis (3.58 vs 2.56 mL, respectively; P = .019), the peroneal tendons (2.17 vs 1.7 mL, P = .004), and the accessory peroneus tendon + PB muscle (1.31 vs 0.86 mL, P = .023). CONCLUSION: The current study supports that the PB muscle belly is more distal in patients with peroneal tendon pathology. The study also demonstrates increased total volume within the peroneal sheath among the same patients. We propose that increased volume within the sheath, regardless of what structure is enlarged, is associated with peroneal tendon pathology. Further studies are needed to determine if debridement and decompression of the sheath will result in improved functional outcomes for these patients. LEVELS OF EVIDENCE: Level III: Case control imaging study.

Risk Factors for Aseptic Revision of Operatively Treated Ankle Fractures.

BACKGROUND: Early revision rates within 12 months after ankle fracture open reduction internal fixation (AF-ORIF) are fairly low; however, they remain relevant given the volume of ankle fractures occurring annually. Understanding these rates is complex because reoperation due to technical or mechanical complications is typically reported alongside soft tissue-related problems such as symptomatic hardware, wound dehiscence, or infection. There are limited data identifying risk factors specifically for revision of ankle fracture fixation in the absence of soft tissue complications. Understanding variables that predispose to aseptic technical and mechanical failure without this confounder may provide insight and improve patient care. METHODS: A retrospective cohort study was performed at 2 large academic medical centers. Research Patient Data Registry (RPDR) data available from 2002 to 2019 were used to identify patients who underwent aseptic revision of AF-ORIF within 12 months (n = 33). A control group (n = 100) was selected by identifying sequential patients who underwent AF-ORIF not requiring revision within 12 months. Multiple factors were recorded for all patients in both cohorts. Each fracture was also evaluated according to the Ankle Reduction Classification System (ARCS) of Chien et al,8 which categorizes biplanar talar displacement in relation to a central tibial plumb line into 1 of 3 grades: A (0-2 mm), B (3-10 mm), and C (>10 mm). Adapted from its original purpose of grading reduction quality, we applied ARCS to pre-reduction radiographs to assess initial fracture displacement. All variables collected were compared in univariate analysis. Variables that achieved significance in univariate comparisons were included as candidates for multivariable analysis. RESULTS: Final multivariable logistic regression modeling demonstrated the following factors to independently predict the need for aseptic revision surgery: documented falls in the early postoperative period (aOR, 298; 95% CI, 15.4, 5759; P < .001), movement-altering disorders (aOR, 81.7; 95% CI, 4.12, 1620; P = .004), a nonanatomic mortise (medial clear space [MCS] > superior clear space [SCS]) on immediate postoperative imaging (aOR, 38.4; 95% CI, 5.53, 267; P < .001), initial coronal plane tibiotalar displacement >10 mm and sagittal plane tibiotalar dislocation (ARCS-C) (aOR vs ARCS-A, 25.8; 95% CI, 2.81, 237; P = .004), substance abuse (aOR, 15.7; 95% CI, 2.66, 92.8; P = .002), and polytrauma (aOR, 12.3; 95% CI, 2.02, 74.8; P = .006). CONCLUSION: In this investigation we found a notable increase in risk for revision surgery after AF-ORIF for patients who had one of the following: (1) falls in the early postoperative period, (2) movement-altering disorders, (3) a nonanatomic mortise (MCS > SCS) on immediate postoperative imaging, (4) more severe initial fracture displacement, (5) substance abuse, or (6) polytrauma. Identifying these factors may allow surgeons to better understand risk and counsel patients, and may serve as future targets for intervention aimed at improving patient safety and outcomes after ankle fracture ORIF. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

The Lateral Drawer Test: A New Clinical Test to Assess Mortise Instability in Weber B Fibula Fractures.

Background: Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. Although instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the isolated Weber B fibula fracture often requires further investigation. Prior authors have demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis, and swelling with instability. The goal of this study is to test the validity of a new clinical examination maneuver, the lateral drawer test, against the gravity stress view (GSV) in a cohort of patients with Weber B fibula fractures. Secondary goals included assessing pain tolerability of the lateral drawer test, as well as testing interobserver reliability. Methods: Sixty-two patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three nonweightbearing radiographic views of the ankle as well as a GSV were obtained. Radiographs were not visualized before conducting the lateral drawer test. Two foot and ankle fellowship-trained orthopaedic surgeons performed and graded the lateral drawer test. Radiographs were then examined and medial clear space (MCS) was measured. Visual analog scale (VAS) pain scores were obtained before and after testing. The results of the lateral drawer test were compared with radiographic measurements of MCS on GSV. A cadaveric experiment was devised to assess interobserver reliability of the lateral drawer test. Results: Thirty (48%) of 62 consecutively enrolled patients demonstrated radiographic instability with widening of the MCS ≥5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83%, specificity of 97%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 86%. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (Spearman correlation ρ = 0.82, P < .005). Patients tolerated the maneuver well with an average increase of 0.7 on the VAS pain scale. Testing of 2 observers utilizing the cadaveric model demonstrated a Cohen's Kappa coefficient of 0.7 indicating moderate interobserver agreement. Conclusion: The lateral drawer test demonstrates high sensitivity, specificity, PPV, and NPV with moderate interobserver reliability compared with the MCS on GSV in patients presenting with Weber B fibula fractures. Although further external validation is required, the lateral drawer test may offer an adjunct tool via physical examination to help determine mortise stability. Level of Evidence: Level II, Prospective Cohort Study.