Intravenous Cefazolin Achieves Sustained High Interstitial Concentrations in Open Lower Extremity Fractures.

BACKGROUND: Infection remains a serious clinical concern in patients with open fractures, despite timely antibiotic administration and surgical debridement. Soft tissue and periosteal stripping may alter local tissue homeostasis and antibiotic pharmacokinetics in the injured limb. The tissue (interstitial) concentration of intravenously administered antibiotics at an open fracture site has not been characterized using direct sampling techniques. QUESTION/PURPOSE: We performed this study to evaluate the concentration and pharmacokinetics of intravenously delivered cefazolin at an open fracture site after surgical debridement. METHODS: Twelve patients with an open fracture distal to the knee who presented at a regional Level I trauma center were approached for enrollment in this nonrandomized, observational study. Of the 12 patients, eight adults (one female, seven male) with a median age of 32 years (range 23 to 51 years) were enrolled and underwent successful sample collection for analysis. Three patients had incomplete datasets because of equipment malfunction and one elected not to participate. Seven patients had open tibia fractures, and one patient had an open fibula fracture associated with a closed tibia fracture. There were six Gustilo-Anderson Type II injuries and two Type IIIA injuries. Empiric antibiotics were administered in the prehospital setting or in the emergency department according to institutional protocol. When patients were taken to the operating room, a 2-g intravenous dose of cefazolin was administered. After surgical debridement, fracture stabilization, and wound closure, a microdialysis catheter was placed transdermally into the injury zone (within 5 cm of the fracture site) and a second catheter was placed in the contralateral uninjured (control) limb. Additional doses of cefazolin were administered every 8 hours postoperatively. Baseline and periodic interstitial fluid and whole blood (plasma) samples were collected in the operating room and at prespecified times for 24 hours postoperatively. Free cefazolin in the interstitial fluid and plasma samples were analyzed by ultra-high-performance liquid chromatography using C 18 column separation with quadrupole time-of-flight mass spectrometry detection. Data from the second postoperative dose of cefazolin were used to characterize pharmacokinetic parameters through a noncompartmental analysis using time-concentration curves of free cefazolin and assuming first-order elimination. For pharmacodynamic analyses, the modal cefazolin minimum inhibitory concentration (MIC) of Staphylococcus aureus (1 µg/mL) was used. RESULTS: With the samples available, no difference was observed in the median free cefazolin exposure over 24 hours ( f area under the curve [AUC] 0→24hrs ) between injured limbs (352 µg∙hr/mL [IQR 284 to 594 µg∙hr/mL]) and uninjured limbs (341 µg∙hr/mL [IQR 263 to 438 µg∙hr/mL]; p = 0.64). The median time to achieve the maximum concentration of free cefazolin ( f T max ) for injured limbs was delayed (2.7 hours [IQR 2.2 to 3.1 hours]) compared with control limbs (1.7 hours [IQR 1.2 to 2.0 hours]; p = 0.046). The time to the maximum concentration for plasma was not different from that of control limbs (p = 0.08). The time the cefazolin concentration was above the modal S. aureus MIC (T > MIC) in the injured and control limbs over 24 hours was 100% (IQR 100% to 100%) and 100% (IQR 97% to 100%), respectively. CONCLUSION: These preliminary findings suggest that current prophylactic cefazolin dosing regimens result in successful antibiotic delivery to the traumatized limb in moderately severe open fractures. Although cefazolin delivery to open-fracture wound beds was delayed compared with healthy tissues, the cefazolin concentration was sustained above the European Union Committee Antimicrobial Susceptibility Testing modal MIC for S. aureus , demonstrating a high likelihood of a prophylactic antimicrobial environment at an open fracture site with this empiric antimicrobial regimen. Importantly, patients in this analysis had Gustilo-Anderson Types II and IIIA injuries. Further research with a larger patient cohort is needed to determine whether antibiotic delivery to traumatized soft tissues in patients with higher-grade open fractures (Gustilo-Anderson Types IIIB and IIIC) demonstrates similar pharmacokinetic characteristics. LEVEL OF EVIDENCE: Level II, therapeutic study.

Magnetic resonance imaging does not reliably detect Kaplan fiber injury in the setting of anterior cruciate ligament tear.

PURPOSE: There has been a continued effort to better understand the role Kaplan fiber injury plays in persistent instability following ACL tears. However, the prevalence of these injuries remains poorly understood. Therefore, the purpose of this study was to define the prevalence of Kaplan fiber injury in the setting of complete anterior cruciate ligament tear using a commonly used grading system for assessing ligament injuries. The inter-rater reliability of this commonly used grading system and the relationship between Kaplan fiber injury and injury to other structures commonly found in conjunction with ACL tears was also evaluated. METHODS: All isolated, complete anterior cruciate ligament tears confirmed on magnetic resonance imaging within 90 days of injury between 2014 and 2020 at a single institution were included for analysis. Each scan was read by two, fellowship-trained musculoskeletal radiologists. Kaplan fiber injury was evaluated using a previously described grading scheme. Kappa, [Formula: see text], of inter-rater agreement was determined for all magnetic resonance image scans. Kruskal Wallis test was performed to assess for associations between Kaplan fiber injury and magnet strength (1.5 T vs. 3.0 T), patient gender, the presence of medial and/or lateral meniscal tears, and/or posterolateral tibial bone bruise. RESULTS: Between 2014 and 2020, 131 patients (94 males, 37 females) with a complete anterior cruciate ligament tear were included in the final analysis. The mean age of the cohort was 27.8 ± 6.8 years. Kaplan fiber injuries were identified in 51 of 131 (38.9%, CI 31.0-47.5%) scans with complete anterior cruciate ligament injuries (Grade 1: 28, Grade 2: 18, and Grade 3: 5). Inter-rater agreement for Kaplan fiber injury was fair ([Formula: see text] with 43 (32.8%) scans requiring third reviewer adjudication. There were no significant associations between Kaplan fiber injury and gender, magnet strength, meniscal tears, or posterolateral tibial bone bruise. CONCLUSION: The prevalence of Kaplan fiber injuries was comparable to previously described rates; however, the classification system used to report Kaplan fiber injury was associated with low inter-rater reliability. The presence of Kaplan fiber injury was not associated with other injuries commonly observed in conjunction with ACL tear. The previously proposed Kaplan fiber injury classification system is not reproducible nor is it likely to aid surgeons in distinguishing higher grades of rotatory knee instability. LEVEL OF EVIDENCE: Level IV.

Similar rates of reoperation for neuroma after transtibial amputations with and without targeted muscle reinnervation.

Objective: To compare the rates of revision surgery for symptomatic neuromas in patients undergoing primary transtibial amputations with and without targeted muscle reinnervation (TMR). Design: Retrospective cohort study. Setting: Level I trauma hospital and tertiary military medical center. Patients/Participants: Adult patients undergoing transtibial amputations with and without TMR. Intervention: Transtibial amputation with targeted muscle reinnervation. Main Outcome Measurements: Reoperation for symptomatic neuroma. Results: During the study period, there were 112 primary transtibial amputations performed, 29 with TMR and 83 without TMR. Over the same period, there were 51 revision transtibial amputations performed, including 23 (21%) in the patients undergoing primary transtibial amputation at the study institution. The most common indications for revision surgery were wound breakdown/dehiscence (42%, n = 25), followed by symptomatic neuroma 18% (n = 9/51) and infection/osteomyelitis (17%, n = 10) as the most common indications. However, of the patients undergoing primary amputation at the study's institution, there was no difference in reoperation rates for neuroma when comparing the TMR group (3.6%, n = 1/28) and no TMR group (4.0%, n = 3/75) (P = 0.97). Conclusions: Symptomatic neuroma is one of the most common reasons for revision amputation; however, this study was unable to demonstrate a difference in revision surgery rates for neuroma for patients undergoing primary transtibial amputation with or without targeted muscle reinnervation. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

At-Risk Median Motor Branch to the Thenar Musculature Crossing Under the Flexor Carpi Radialis in the Forearm: A Case Report.

CASE: A 77-year-old woman who sustained a distal radius and ulna fracture underwent open reduction internal fixation through a standard flexor carpi radialis (FCR) approach. On dissection, a proximal division of the median nerve was identified, with an aberrant motor branch crossing radial to ulnar deep to FCR and superficial to flexor pollicis longus. CONCLUSION: Although many anatomic variants of the median nerve have been described, the current case demonstrates a particularly important median motor branch variant, imposing a substantial risk of iatrogenic injury during a standard FCR approach.

Quadriceps Dysfunction Following Joint Preservation Surgery: A Review of the Pathophysiologic Basis and Mitigation Strategies.

PURPOSE OF REVIEW: To characterize quadriceps muscle dysfunction associated with knee joint preservation surgery, with a focus on its pathophysiology and promising approaches to mitigate its impact on clinical outcomes. RECENT FINDINGS: Quadriceps dysfunction (QD) associated with knee joint preservation surgery results from a complex interplay of signaling, related to changes within the joint and from those involving the overlying muscular envelope. Despite intensive rehabilitation regimens, QD may persist for many months postoperatively and negatively impact clinical outcomes associated with various surgical procedures. These facts underscore the need for continued investigation into the potential detrimental effects of regional anesthetic and intraoperative tourniquet use on postoperative quadriceps function, with an outward focus on innovation within the field of postoperative rehabilitation. Neuromuscular stimulation, nutritional supplementation, cryotherapy, blood flow restriction (BFR), and open-chain exercises are all potential additions to postoperative regimens. There is compelling literature to suggest that these modalities are efficacious and may diminish the magnitude and duration of postoperative QD. A clear understanding of QD, with respect to its pathophysiology, should guide perioperative treatment and rehabilitation strategies and influence ongoing rehabilitation-based research and innovation. Moreover, clinicians must appreciate the magnitude of QD's effect on diminished clinical outcomes, risk for re-injury and patients' ability (or inability) to return to pre-injury level of activity following knee joint preservation procedures.

Medial Elbow Exposure: Modified Taylor-Scham Versus Flexor Carpi Ulnaris-Split.

OBJECTIVE: To compare the exposure of the coronoid process, anteromedial facet, and anterior band of the medial collateral ligament using the flexor carpi ulnaris (FCU)-splitting approach with the Taylor-Scham approach modified with an ulnar nerve transposition. METHODS: Thirty approaches were performed on 15 fresh cadavers using a randomized cross-over design and standardized incision. Access to key anatomic landmarks was assessed, and a calibrated digital image was taken from the surgeon's best perspective of each approach. Images were analyzed using ImageJ (National Institutes of Health) software to calculate the area of osseous exposure. RESULTS: All key anatomic landmarks were visualized using both approaches. The average area of exposure for the Taylor-Scham was 19.5 cm 2 compared with 13.6 cm 2 for the FCU-splitting ( P < 0.0001). The distal extent of the FCU-splitting approach is limited by the ulnar nerve and its branches to the humeral head of the FCU. CONCLUSION: The Taylor-Scham approach provides a more extensile exposure of the anteromedial coronoid and proximal ulna than the FCU-splitting approach while avoiding cross-tensioning of the ulnar nerve.

Treatment of Cartilage Defects of the Knee in Military Tactical Athletes: An Overview of Management and Clinical Outcomes.

Cartilage defects of the knee are a common problem that can be caused by trauma or chronic repetitive overload and result in debilitating functional limitations. These consequences are of particular significance to military service members, who, by in large, are a group of young, active individuals with professional duties requiring full, unrestricted activity and function. The burden of knee chondral-related disease among military tactical athletes is well established, and systematic approach to the evaluation of a military member with suspected knee chondral pathology facilitates the execution of a surgical procedure that maximizes the likelihood of a return to duty. Despite advances in cartilage restoration surgery, chondral pathology of the knee remains a vexing problem and an omnipresent threat to military medical readiness and warfighter lethality.

High Incidence of Combined and Posterior Labral Tears in Military Patients With Operative Shoulder Instability.

BACKGROUND: Anterior shoulder instability is the pattern most commonly reported in the civilian population, but military servicemembers may represent a unique population. At 1.7 per 1000 person-years, servicemembers not only have a higher incidence of instability events compared with civilians (reported rate of 0.2-0.8), but the distribution of labral tears in the military may differ significantly as well. HYPOTHESIS: The incidence of combined and posterior labral tears in the military population will be greater than numbers previously reported. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: The Wounded, Ill, and Injured Registry, a Department of Defense patient reported outcomes data collection platform that includes all military branches, was queried retrospectively for all patients who had undergone a primary arthroscopic or open shoulder stabilization procedure (Current Procedural Terminology codes 29806, 23455, 23462) between October 2016 and January 2019. Demographic information was obtained through intake forms completed by patients at the time of enrollment into the Military Orthopaedics Tracking Injuries and Outcomes Network. Tear location was determined arthroscopically and labeled as anterior, inferior, posterior, superior, or any combination thereof. Chi-square analysis was used to compare the percentage of patients with isolated anterior, isolated posterior, isolated inferior, or combined labral tears in the current study cohort with those in a previously reported cohort of patients with operative shoulder instability at a single military treatment facility. RESULTS: A total of 311 patients were included who had undergone primary shoulder stabilization during the study period. Of these patients, 94 (30.2%) had isolated anterior tears, 76 (24.4%) had isolated posterior tears, and 136 (43.7%) had combined tears. We observed a higher percentage of combined tears in our data set than in a data set from a single military treatment facility (χ2(2) = 48.2; P < .00001). Chi-square analysis demonstrated that significantly more female patients had an isolated anterior labral tear (51.2%) compared with male patients (27.1%; χ2(2) = 9.4; P = .009). CONCLUSION: The incidence of combined and posterior labral tears in the military population is greater than numbers previously reported in both military and civilian populations.

MRI Does Not Reliably Detect Kaplan Fiber Injury In Skeletally Immature Patients with an Acute ACL Tear.

Background: To our knowledge, there have been no previous efforts to evaluate the prevalence of Kaplan fiber (KF) injury in skeletally immature patients with an acute anterior cruciate ligament (ACL) tear on magnetic resonance imaging (MRI) nor has there been any comparison of the reliability of previously described KF diagnostic criteria in this cohort. Purpose: To define the prevalence of KF injury in the setting of acute ACL tears using MRI performed within 90 days of injury among skeletally immature patients, and to compare the reliability of MRI in detecting KF injuries using 2 previously described diagnostic criteria. Study Design: Cohort study; Level of evidence, 3. Methods: Skeletally immature patients with an acute ACL tear confirmed using MRI within 90 days of injury were assessed. Two fellowship-trained musculoskeletal radiologists independently interpreted each MRI scan twice. KF injury was first assessed using the Van Dyck scheme (grade 0, normal; grade 1, periligamentous; grade 2, partial tear; and grade 3, complete tear). MRI scans were then reviewed again using the KF injury criteria proposed by Batty. Discrepancies in KF injury schemes were adjudicated by a third musculoskeletal radiologist. Interrater agreement for both methods was determined using Cohen κ. Results: Included were 45 patients (33 male, 12 female) with a mean age of 13.2 ± 1.6 years. KF injuries were identified in 17 of 45 (37.7%) knees of using the traditional Van Dyck grading scheme (interrater agreement κ = 0.40). The Batty diagnostic criteria identified KF injury in 5 of 45 (11.1%) (interrater agreement κ = 0.45); 17 (37.8%) MRI scans required a third reviewer adjudication for the Van Dyck scheme, while 4 (8.9%) required a third reviewer using the Batty criteria. Conclusion: The Batty diagnostic criteria detected a lower KF injury prevalence than previously reported in the adult population, while the Van Dyck prevalence was similar to rates in adult populations. Both grading criteria had poor interrater reliability in diagnosing a KF injury.

Anatomy and Biomechanics of the Posterior Cruciate Ligament.

Posterior cruciate ligament (PCL) injuries are often encountered in the setting of other knee pathology and sometimes in isolation. A thorough understanding of the native PCL anatomy is crucial in the successful treatment of these injuries. The PCL consists of two independent bundles that function in a codominant relationship to perform the primary role of resisting posterior tibial translation relative to the femur. A secondary role of the PCL is to provide rotatory stability. The anterolateral (AL) bundle has a more vertical orientation when compared with the posteromedial (PM) bundle. The AL bundle has a more anterior origin than the PM bundle on the lateral wall of the medial femoral condyle. The tibial insertion of AL bundle on the PCL facet is medial and anterior to the PM bundle. The AL and PM bundles are 12-mm apart at the center of the femoral origins, while the tibial insertions are more tightly grouped. The different spatial orientation of the two bundles and large distance between the femoral centers is responsible for the codominance of the PCL bundles. The AL bundle is the dominant restraint to posterior tibial translation throughout midrange flexion, while the PM bundle is the primary restraint in extension and deep flexion. Biomechanical testing has shown independent reconstruction of the two bundles that better reproduces native knee biomechanics, while significant differences in clinical outcomes remain to be seen. Stress X-rays may play an important role in clinical decision-making process for operative versus nonoperative management of isolated PCL injuries. Strong understanding of PCL anatomy and biomechanics can aid surgical management.

Primary ACL Repair of a Chronic ACL Femoral Avulsion with 2-Year Clinical and Radiographic Outcomes: A Case Report.

CASE: There has been a reemergence of anterior cruciate ligament (ACL) repair. We present the unique case of an ACL repair in a service member with a chronic tear. The patient went on to have a successful outcome with return to full activities without symptoms and functional outcomes scores equal to preinjury levels. CONCLUSION: This case demonstrates a preserved ACL remnant after an ACL femoral avulsion secondary to scarring to the posterior cruciate ligament. ACL repair can produce excellent outcomes in the right population, and injury chronicity may not necessarily preclude successful repair in the setting of good-quality ACL remnant.

A Rare Presentation of Brodie Abscess in the Clavicle.

A 12-year-old otherwise healthy boy presented with acute shoulder pain and remote history of trauma. Despite an unimpressive clinical examination, laboratory workup, and initial radiographic evaluation, the patient was ultimately diagnosed with a Brodie abscess of the distal clavicle. Complete resolution was achieved with débridement and tailored antibiotic therapy. These abscesses are rare, often presenting surreptitiously with nonspecific symptoms and without systemic signs of infection. Therefore, maintaining a broad differential and high clinical suspicion is crucial to mitigate the increased morbidity that can result from a delayed diagnosis.

Fulminant Pyoderma Gangrenosum After Outpatient Knee Arthroscopy.

Pyoderma gangrenosum is an immunologic, ulcerative cutaneous condition often associated with systemic disease and frequently precipitated by trauma. It is noninfectious, but the inflammatory assault can resemble a malignant infection such as necrotizing fasciitis. Despite its clinical resemblance to infection, surgical débridement worsens the condition and may remove morphologic clues to the true disease, thus creating a vicious cycle of surgical débridements and disease progression. Furthermore, diagnostic histopathologic and laboratory features are nonspecific, requiring exclusion of other processes. Therefore, appropriate nonsurgical treatment and immunosuppression are commonly delayed, often at a significant cost to the patient. We present a case of pyoderma gangrenosum occurring after outpatient knee arthroscopy that masqueraded as a postsurgical infection. We discuss the diagnostic approach and how a complex reconstruction involving cartilage restoration and soft-tissue coverage was achieved.

Osteophyte-Sparing Treatment of Mucous Cysts: Case Analysis and Surgical Technique.

OBJECTIVE: The purpose of this study was to examine patient outcomes and the risk of recurrence of mucous cysts affecting the distal interphalangeal (DIP) joint in the absence of osteophytectomy using the described flap technique. METHODS: A retrospective review of 143 records of patients who were treated for mucous cysts of the DIP joint by a single surgeon. Inclusion criteria included the absence of an osteophytectomy during treatment using the described dorsally based flap technique and a minimum of 12 months of follow-up. RESULTS: A total of 143 mucous cysts affecting the DIP joint of 131 patients with an average age of 65.3 years were included. The average follow-up was 21.9 months (12 to 139). Postoperative DIP joint extension was less in the surgical digit compared with the same digit of the contralateral hand with a significant change from the preoperative motion (1.5° versus 0.3°; P = 0.05). No significant change in the postoperative flexion of the DIP joint was observed compared with that of the contralateral side (-1.4° versus -0.9°; P = 0.57). Recurrence occurred in 2 patients (1.4%). No infections or wound complications were identified. CONCLUSIONS: Using the described technique without an osteophytectomy seemed to be an effective treatment of mucous cysts originating from the DIP joint.

Current Practice Patterns in Anterior Cruciate Ligament Reconstruction Among Fellowship-Trained Military Orthopaedic Surgeons.

PURPOSE: To evaluate current practice patterns in anterior cruciate ligament reconstruction (ACLR) surgery among fellowship-trained military surgeons. METHODS: The MOTION database is a prospectively collected dataset of intraoperative variables across the Military Health System. This database was queried using Current Procedural Terminology code 29888 for ACLR among active-duty service members between October 2016 and December 2019. The intraoperative data pertaining to ACLR involving both isolated primary ACLRs and primary ACLRs combined with meniscal or chondral injuries were extracted with patient age, sex, and rank. RESULTS: Two hundred sixty-six primary ACLRs performed by 21 fellowship-trained orthopaedic surgeons at 9 MTFs were identified. The mean age of patients undergoing ACLR was 27.2 ± 7.7 years. Bone-patellar tendon-bone autograft was the most commonly used graft source (137 of 266 [51.5%] cases.) Meniscal injuries were treated with an isolated debridement in 53 of 156 (34.0%) tears, whereas meniscal repair was performed in 86 of 156 (55.1%) tears. Concomitant chondral pathology was noted in 43 of 266 cases (16.2%) and most commonly addressed with chondroplasty (25 of 49 [51.0%] chondral lesions). CONCLUSIONS: Bone-patellar tendon-bone autograft was the most commonly used graft type in ACLR among fellowship-trained surgeons treating active-duty service members. Concomitant meniscal pathology was encountered at rates comparable with what has been previously reported, and meniscal repair was favored over meniscal debridement in more than 50% cases. LEVEL OF EVIDENCE: Level IV: Therapeutic case series.

Design, synthesis, and evaluation of a liposaccharide drug delivery agent: application to the gastrointestinal absorption of gentamicin.

The design, synthesis, and evaluation of a liposaccharide (11) for use as an agent to enhance the gastrointestinal absorption of charged, hydrophilic drugs with poor membrane permeability is reported. 11 was designed to possess both surfactant and ion-pairing properties and was conveniently synthesized from d-glucuronic acid (2) and N-Boc-lipoamino acid (5) precursors in eight steps in good yield. Isothermal titration microcalorimetry was used to determine the critical micelle concentration of 11 (in PBS) to be 2.09 +/- 0.01 mM with an enthalpy of demicellization of 4.91 +/- 0.11 kJ/mol. The ability of 11 to enhance the gastrointestinal absorption of the aminoglycoside antibiotic gentamicin (1), a hydrophilic polycation with negligible oral bioavailability, was assessed in vivo using rats. Rats dosed orally with a mixture of 11 (100 mg/kg) and 1 (60 mg/kg) had a statistically significant (P < or = 0.034) increase in Cmax, AUC120, and percent absolute bioavailability (F) compared to control 1 (60 mg/kg) alone. The highest bioavailability (F = 9.1 +/- 2.0%) was achieved by dosing with the mixture 11 (100 mg/kg) and 1 (15 mg/kg). This represents a 6-fold increase in bioavailability compared to the control (F = 1.4 +/- 0.3%). These results suggest that the molar ratio of 1:11 may be critical in optimizing the delivery system, a finding ascribed in part to the ion-pairing properties of 11. The effect of 11 on the gastrointestinal mucosa was assessed using light microscopy to examine tissue samples from rats used in the pharmacokinetic study. No morphological changes were found in either the esophagi or duodena of the rats examined. One rat dosed with 11 (100 mg/kg) and 1 (60 mg/kg) exhibited slight gastric erosion, which could be attributed to 11.