Psoriasis Is a Risk Factor for Surgical Site Infection After Primary TKA.

BACKGROUND: The relationship between psoriasis and complications after primary TKA is not well defined. Current studies are limited to small, single-center studies evaluating fewer than 150 patients with psoriasis, with some studies reporting an increased risk of surgical site infection (SSI) and another reporting no associated risk. There is a need to reevaluate the risk of psoriasis and postoperative complications, including SSI, to better risk-stratify and guide practice in this patient population. QUESTIONS/PURPOSES: (1) Compared with patients without psoriasis, after accounting for potential confounders such as age, insurance, and comorbidities, do patients with psoriasis have a higher odds of superficial SSI after primary TKA? (2) Do patients with psoriasis have a higher odds of deep SSI after primary TKA? METHODS: Patients 18 years or older who underwent unilateral, primary TKA between 2015 and 2019 were identified in the PearlDiver database (n = 490,722). Patients with rheumatoid, septic, or posttraumatic arthritis were excluded, as well as patients with bone neoplasias (n = 188,557). Additionally, patients with less than 2 years of follow-up (n = 53,673) were excluded. In all, 248,492 patients were included in this study; 0.4% (1078) were in the psoriasis group and 99% (247,414) were in the control group. Overall 2-year superficial and deep SSI rates were stratified and compared between patients with psoriasis and a control group of patients who did not have psoriasis as the primary outcome. Secondary outcomes included the odds of undergoing an aseptic revision or manipulation under anesthesia. RESULTS: In the multivariable analysis, which controlled for potential confounders such as age, sex, Elixhauser comorbidity index, hypertension, diabetes mellitus, and liver disease, the odds of SSI-either superficial or deep-remained higher for patients with psoriasis (OR 1.74 [95% confidence interval 1.03 to 2.96]; p = 0.04). When focusing on superficial infections in the multivariable analysis, patients with psoriasis had a higher odds of superficial SSI than those in the control group (OR 2.83 [95% CI 1.26 to 6.34]; p = 0.01). The odds of deep SSI were not different between the two cohorts in our multivariable analysis (OR 1.32 [95% CI 0.66 to 2.66]; p = 0.43). Patients with psoriasis did not have an increased odds of undergoing an aseptic revision (OR 0.79 [95% CI 0.48 to 1.32]; p = 0.38) or manipulation under anesthesia (OR 0.74 [95% CI 0.52 to 1.06]; p = 0.10). CONCLUSION: Patients with psoriasis had higher overall rates of SSI at 2 years of follow-up than patients without psoriasis. Our findings suggest that psoriasis is a risk factor for superficial SSI after primary TKA and is an important comorbidity for surgeons to consider before surgery. Further research is needed to assess the role of adjunctive interventions in patients with psoriasis to mitigate the elevated odds of superficial SSI. LEVEL OF EVIDENCE: Level II, prognostic study.

Targeting the tetraspanin CD81 reduces cancer invasion and metastasis.

Tetraspanins are an evolutionary conserved family of proteins involved in multiple aspects of cell physiology, including proliferation, migration and invasion, protein trafficking, and signal transduction; yet their detailed mechanism of action is unknown. Tetraspanins have no known natural ligands, but their engagement by antibodies has begun to reveal their role in cell biology. Studies of tetraspanin knockout mice and of germline mutations in humans have highlighted their role under normal and pathological conditions. Previously, we have shown that mice deficient in the tetraspanin CD81 developed fewer breast cancer metastases compared to their wild-type (WT) counterparts. Here, we show that a unique anti-human CD81 antibody (5A6) effectively halts invasion of triple-negative breast cancer (TNBC) cell lines. We demonstrate that 5A6 induces CD81 clustering at the cell membrane and we implicate JAM-A protein in the ability of this antibody to inhibit tumor cell invasion and migration. Furthermore, in a series of in vivo studies we demonstrate that this antibody inhibits metastases in xenograft models, as well as in syngeneic mice bearing a mouse tumor into which we knocked in the human CD81 epitope recognized by the 5A6 antibody.

Initiation of Bisphosphonates Prior to Total Joint Arthroplasty Does Not Lower Periprosthetic Fracture Risk.

BACKGROUND: Many patients are diagnosed with osteoporosis shortly prior to scheduling total joint arthroplasty (TJA). The purpose of this study was to determine if initiation of bisphosphonates prior to TJA decreased the risks of periprosthetic fractures (PPFx). METHODS: A national database was used to identify all patients diagnosed with osteoporosis prior to primary TJA. Patients who had osteoporosis without preoperative bisphosphonate use were designated as our control group. Patients on preoperative bisphosphonates were stratified based on duration and timing of bisphosphonate use: long-term preoperative users (initiation 3 to 5 years preoperatively), intermediate-term preoperative users (initiation 1 to 3 years preoperatively), and short-term preoperative users (initiation 0 to 1 year preoperatively). Rates of PPFx at 90-day and 2-year follow-up were compared between groups. RESULTS: In patients undergoing primary total hip arthroplasty, there was no difference in PPFx rate between our control group and preoperative bisphosphonate users of all durations at 90-day (P = .12) and 2-year follow-up (P = .22). In patients undergoing primary total knee arthroplasty, there was no difference in PPFx rate between our control group and preoperative bisphosphonate users of all durations at 90-day (P = .76) and 2-year follow-up (P = .39). CONCLUSIONS: In patients undergoing primary TJA, preoperative bisphosphonate users did not have a decreased PPFx rate compared to our control group at 90-day and 2-year follow-up. Our findings suggest that preoperative bisphosphonate use, regardless of the duration of treatment, does not confer protective benefits against PPFx in patients undergoing TJA. LEVEL OF EVIDENCE: Prognostic Level III.

Higher Complication Rate in COVID-19 Recovered Patients Undergoing Primary Total Joint Arthroplasty.

BACKGROUND: There is limited data reviewing complication risks associated with total joint arthroplasty (TJA) after recovering from COVID-19. This study evaluated complications within 90 days of TJA in patients who had a COVID-19 diagnosis at varying intervals prior to surgery versus a non-COVID-19 cohort. METHODS: A large national database was used to identify patients diagnosed with COVID-19 in the six months prior to total hip arthroplasty (THA) or total knee arthroplasty. The incidence of complications within 90 days of surgery was recorded and compared to a COVID-19 negative control group matched 1:3 for age range in 5-year intervals, Charlson Comorbidity Index, and sex. There were 7,780 patients included in the study; 5,840 (75.1%) never diagnosed with COVID-19, 1,390 (17.9%) who had a COVID-19 diagnosis 0 to 3 months prior to surgery, and 550 (7.1%) who had a COVID-19 diagnosis 3 to 6 months prior to surgery. RESULTS: When compared to their COVID negative controls, patients who had a COVID-19 diagnosis 0 to 3 months prior to surgery had significantly higher rates of readmission (14.0 versus 11.1%, P = .001), pneumonia (2.2 versus 0.7%, P < .001), deep vein thrombosis (DVT) (3.3 versus 1.9%, P = .001), kidney failure (2.4 versus 1.4%, P = .006), and acute respiratory distress syndrome (1.4 versus 0.7%, P = .01). Patients who had a COVID-19 diagnosis 3 to 6 months prior to surgery had significantly higher rates of pneumonia (2.0 versus 0.7%, P = .002) and DVT (3.6 versus 1.9%, P = .005) when compared to their COVID negative controls. CONCLUSION: Patients diagnosed with COVID-19 within three months prior to TJA have an increased risk of 90-day postoperative complications. Risk for pneumonia and DVT remains elevated even when surgery was performed as far as 3 to 6 months after COVID-19 diagnosis.

Chitinase-Like Protein Ym2 (Chil4) Regulates Regeneration of the Olfactory Epithelium via Interaction with Inflammation.

The adult olfactory epithelium (OE) regenerates sensory neurons and nonsensory supporting cells from resident stem cells after injury. How supporting cells contribute to OE regeneration remains largely unknown. In this study, we elucidated a novel role of Ym2 (also known as Chil4 or Chi3l4), a chitinase-like protein expressed in supporting cells, in regulating regeneration of the injured OE in vivo in both male and female mice and cell proliferation/differentiation in OE colonies in vitro We found that Ym2 expression was enhanced in supporting cells after OE injury. Genetic knockdown of Ym2 in supporting cells attenuated recovery of the injured OE, while Ym2 overexpression by lentiviral infection accelerated OE regeneration. Similarly, Ym2 bidirectionally regulated cell proliferation and differentiation in OE colonies. Furthermore, anti-inflammatory treatment reduced Ym2 expression and delayed OE regeneration in vivo and cell proliferation/differentiation in vitro, which were counteracted by Ym2 overexpression. Collectively, this study revealed a novel role of Ym2 in OE regeneration and cell proliferation/differentiation of OE colonies via interaction with inflammatory responses, providing new clues to the function of supporting cells in these processes.SIGNIFICANCE STATEMENT The mammalian olfactory epithelium (OE) is a unique neural tissue that regenerates sensory neurons and nonsensory supporting cells throughout life and postinjury. How supporting cells contribute to this process is not entirely understood. Here we report that OE injury causes upregulation of a chitinase-like protein, Ym2, in supporting cells, which facilitates OE regeneration. Moreover, anti-inflammatory treatment reduces Ym2 expression and delays OE regeneration, which are counteracted by Ym2 overexpression. This study reveals an important role of supporting cells in OE regeneration and provides a critical link between Ym2 and inflammation in this process.

Robotic colorectal procedures: does operative start time impact short-term outcome?

BACKGROUND: Previous publications revealed more complications in afternoon versus morning surgeries. With much attention given to robotic surgery outcomes, we sought to evaluate whether morning versus afternoon start time matters. METHODS: In a retrospective review of a prospective database, 210 robotic colorectal surgeries were grouped into 97 morning versus 113 afternoon cases. Preoperative risk factors, intraoperative events, and 30-day postoperative outcomes were compared. An independent samples t-test, Fisher's exact test, and linear regression were used for categorical and continuous variables. RESULTS: Morning patients were significantly younger than afternoon patients (59.5 vs. 65.5, p = 0.004), but there were no significant differences in gender, mean BMI, Charlson Comorbidity Index score, total operative time, console time, estimated blood loss, indications for surgery, and resection type. Morning patients had a significantly shorter mean length of stay (6.0 vs. 8.0 days, p = 0.021), but no significant differences in overall postoperative complications (0.30 vs. 0.30, p = 0.715), wound infection (5.2% vs. 7.1%, p = 0.564), anastomotic leak (0% vs. 2.7%, p = 0.251), ileus/small bowel obstruction (29.9% vs. 22.1%, p = 0.199), and 30-day readmission (8.2% vs. 7.1%, p = 1.000). When analyzing time of day as a continuous variable, we found no significant associations with intra- or postoperative complications. CONCLUSION: We found no correlation between surgery start time and intra- or postoperative outcomes. This can be partly attributed to these cases being non-emergent and performed primarily by two experienced surgeons with highly trained operating room robotic staff in a large volume tertiary center. This, along with decreased fatigue attributed to superior ergonomics of robotic surgery, may have mitigated previously reported differences between morning and afternoon procedures.

Surgeons have an opportunity to improve teaching quality through feedback provision.

BACKGROUND: Medical student evaluations of faculty are increasingly incorporated into promotion and tenure decisions, making it imperative to understand learner perceptions of quality teaching. Prior work has shown that students value faculty responsiveness in the form of feedback, but faculty and students differ in their perceptions of what constitutes sufficient feedback. The innovative minute feedback system (MFS) can quantify responsiveness to students' feedback requests. This study assessed how feedback provision via MFS impacts teaching quality scores. MATERIALS AND METHODS: This retrospective observational study compared average faculty teaching quality scores with faculty's percentage response to student feedback requests via the MFS. The data were generated from the core surgical clerkship for third-year medical students at the University of Michigan Medical School. The relationship between average teaching quality scores and response percentage was assessed by weighted regression analysis. RESULTS: Two hundred thirty-seven medical students requested feedback via MFS, and 104 faculty were evaluated on teaching quality. The mean faculty feedback response percentage was 55.78%. The mean teaching quality score was 4.27 on a scale of 1 to 5. Teaching quality score was significantly correlated with response percentage (P < 0.001); for every 10% increase in response percentage, average teaching quality score improved by 0.075. Average teaching quality score was not significantly associated with response time (P = 0.158), gender (P = 0.407), or surgical service (P = 0.498). CONCLUSIONS: Medical students consider responsiveness to feedback requests an important component of quality teaching. Furthermore, faculty development focused on efficient and practical feedback strategies may have the added benefit of improving their teaching quality.

Anatomy and Deficiency of the Deltoid Muscle: A Review of Literature.

BACKGROUND/OBJECTIVE: The deltoid muscle is impacted by common injuries and clinical procedures. This study aims to summarize the anatomy, injuries, and clinical considerations involving the deltoid muscle. METHOD: A literature search was performed using PubMed and Google Scholar using keywords that focused on the deltoid muscle in the shoulder. Primary research articles and appropriate summary articles were selected for review. RESULTS: Reduced deltoid muscle function can be caused by axillary nerve injury, rupture of the deltoid itself, or iatrogenic damage to the muscle. The deltoid muscle has an intimate relationship with the axillary nerve and neighboring rotator cuff muscles. Injury to these nearby structures may be masked by compensating deltoid strength. Examination maneuvers in clinic such as the Akimbo Test should be used to isolate the deltoid muscle to determine if the presenting weakness is from the deltoid itself or from other surrounding injury. Additionally, prior to performing clinical procedures, it is important to be cognitive of the injuries that can occur. For example, incisions that extend distally from the acromion should not extend beyond 5-7 cm as this is the common location of the axillary nerve and vaccine administration should take measures to avoid misplaced injections to avoid unnecessary trauma. CONCLUSION: Deficiency of the deltoid muscle can be debilitating to patients and it is best clinical practice be aware of the anatomy, various causes, tests, and avoidance measures to help diagnose, restore or preserve normal functioning.

A clinical review of hand manifestations of cervical myelopathy, cervical radiculopathy, radial, ulnar, and median nerve neuropathies.

Cervical spondylotic myelopathy (CSM) is defined as compression of the spinal cord in the neck, resulting in problems with fine motor skills, hand numbness, pain or stiffness of the neck, and difficulty walking due to loss of balance. Brachial plexus (BP) neuropathies arise due to compression to any distal branches arising from C5-T1, whereas cervical radiculopathy involves compression at the nerve root in the neck. Such conditions can present with variable degrees of musculoskeletal pain, weakness, sensory changes, and reflex changes. The pronounced convergence in symptomatic manifestation within these conditions can pose a formidable challenge to clinicians, particularly in primary care. Thus, the primary objective of this paper is to enhance clarity and distinction among these pathological conditions. This objective is pursued through comprehensive delineation of the dermatomal and myotomal distributions characteristic of each condition. Furthermore, a meticulous examination is undertaken to elucidate physical indicators and maneuvers that exhibit a notably high sensitivity in detecting these conditions. Accurate diagnosis and treatment of each nerve pathology is important as long-term spinal cord compression and its roots may result in permanent disability and severely impact one's quality of life. As such, this systematic review serves as a guide that aids clinicians in differentiating the aforementioned conditions based on anatomy, physical exam findings, and imaging studies. Furthermore, this study aims to outline common peripheral nerve neuropathies in the upper extremities and ways to mitigate these pathologies using the least to most invasive treatment modalities.

A systematic review of the operative techniques for treating cubitus varus deformity in children.

A systematic review of the operative techniques for treating cubitus varus deformity in children was performed using research databases including PubMed and Embase. Outcome measurements included mean angular correction of the humerus-elbow-wrist angle, complications, revisions and outcome scores. A total of 45 papers and 911 patients were included. Lateral closing wedge osteotomy (LCWO) (427 patients) was the most common procedure and 5.56% of these patients experienced lateral condylar prominence. This technique had the highest revision rate at 3%. The step-cut osteotomy (111 patients) yielded zero postoperative infections or loss of motion. Distraction osteogenesis (92 patients) was the least common technique. Superficial pin tract infections occurred in 18% of patients and 88.04% of patients reported excellent results, the highest of any technique in this study. The infection rate of dome osteotomy (151 patients) was 9.45% and 4.72% of patients experienced loss of motion. 3D osteotomy (130 patients) had no infections, 87.78% of patients reported excellent outcomes, and 2.22% of patients reported poor outcomes, the lowest of all techniques. For unidimensional correction, LCWO provides a technically simple procedure and reasonable outcomes. Step-cut osteotomy has less lateral condylar prominence but is more complicated than LCWO. Distraction osteogenesis is a minimally invasive alternative to LCWO and step-cut osteotomy, but it has more superficial infections and can be bothersome to patients. For a multidimensional correction, 3D osteotomy is superior to dome osteotomy due to its lower infection rate and higher rate of functionally excellent outcomes.

No Decrease in Early Survivorship of Dual Mobility Implants in Primary Total Hip Arthroplasty.

Background: Dual mobility (DM) implants in primary total hip arthroplasty (THA) have gained recent popularity; however, safety concerns persist. The purpose of this study was twofold: 1) assess trends in DM implant adoption; and 2) evaluate the impact of modular DM implants on dislocation and all-cause revision rates at short-term follow-up. Methods: This retrospective study identified patients in our institutional arthroplasty database who underwent primary posterior approach THA for degenerative conditions from November 2013 to December 2020. Patients undergoing primary THA for fracture were excluded. Patients were divided into two cohorts: modular DM and non-DM implants. Annual DM utilization and dislocation rates were recorded. Patient records were reviewed to determine implant selection and identify indications for dislocations and reoperations. Results: Institutional adoption was rapid, increasing from 3.4% in 2013 to 47.1% in 2020. Of the 4548 primary THA cases from 2013 to 2020, 2859 (62.9%) had minimum one-year follow-up data for inclusion. There were 724 (25.3%) with DM implants and 2135 (74.7%) with non-DM implants. The DM group had a significantly lower dislocation rate (0.14% vs 0.84%, P = .04), with similar all-cause revision rates (2.49% vs 2.72%, P = .74) at one-year follow-up. No cases of DM-specific complications (metallosis or intraprosthetic dislocations) were noted. Conclusions: From 2013 to 2020, DM implant utilization in primary THA steadily increased. Use of modular DM implants is associated with a decreased dislocation rate without compromised survivorship at one-year follow-up when compared to non-DM implants. No instances of modular DM-specific complications were identified; however, longer-term surveillance is necessary to verify these findings. Level of Evidence: Prognostic Level III.

Malseated Liner in Modular Dual Mobility Total Hip Replacement: A Report of Three Cases.

Modular dual mobility total hip arthroplasty (THA) can be associated with complications if the liner is malseated, which can be unappreciated intraoperatively. A meticulous surgical technique is needed to ensure that the liner is perfectly seated. In addition, a malseated liner can be missed if the postoperative films are not carefully reviewed by the surgeon. We present three cases of THA associated with a malseated modular dual mobility liner. In one case, the malpositioned liner was appreciated intraoperatively, but it was wedged in place and could not be removed. The entire shell needed to be revised. In two other cases, malseating was not detected intra-operatively. Both were appreciated postoperatively, and early revision surgery was needed.

Preoperative Depression Is Associated With Increased Short-term Complications But Equivalent Long-term Outcomes in Total Knee Arthroplasty.

Concomitant depression negatively impacts outcomes following total knee arthroplasty (TKA). Patient-Reported Outcomes Measurement Information System (PROMIS) surveys are validated measures that quantify depression, pain, and physical function. We hypothesized that higher preoperative PROMIS-depression scores would be associated with inferior outcomes following TKA. A total of 258 patients underwent primary TKA at a tertiary academic center between June 2018 and August 2020. PROMIS scores were collected preoperatively and at 6 weeks, 3 months, 1 year, and 2 years postoperatively. Patients with preoperative PROMIS depression scores of 55 or greater were considered PROMIS depressed (PD) and patients with scores less than 55 were considered not PROMIS depressed (ND). The primary outcomes were changes in PROMIS scores. Secondary outcomes included total and daily mean morphine milligram equivalents (MME) received during admission as well as 90-day hospital readmission and 2-year all-cause revision rates. There were 66 (25.58%) patients in the PD group and 192 (74.42%) in the ND group. Patients in the PD group had improved depression scores at all follow-up intervals (P<.001) and decreased pain scores at 1 year (P=.016). Both groups experienced similar changes in function scores at each follow-up interval. Patients in the PD group had higher total (P=.176) and daily (P=.433) mean MME use while admitted. Ninety-day hospital readmissions were higher in the PD group (P=.002). There were no differences in 2-year revision rates (P=.648). Preoperative PROMIS-depression scores of 55 or greater do not negatively impact postoperative function, depression, or pain, and patients with these scores have greater improvement in depression and pain at certain intervals. Patients in the PD group had higher readmission rates. [Orthopedics. 2024;47(1):40-45.].

Anatomical and surgical considerations of the pectoralis muscle.

Introduction: The pectoralis major (PM) muscle is the largest and most superior muscle of the anterior chest wall. The PM plays an important role in flexion, adduction, and internal rotation of the arm. The pectoralis major's size, strength, and anatomical location make it an excellent candidate in transfer surgeries due to its ability to restore balancing forces that may be lost in scapular winging and subscapularis tears. Each of these injuries and pathologies involves the PM muscle in some way, and careful consideration of its anatomy and physiology is necessary. This review article aims to provide a comprehensive overview of the anatomy, physiology, and surgical considerations of the pectoralis muscle with a specific focus on the surgical techniques involving the muscle. Methods: A comprehensive literature search using a combination of the following terms: pectoralis major, rupture, transfer, chronic subscapularis tear, pectoralis surgery, anatomy, scapular winging, and long thoracic nerve anatomy. There were no limitations with regards to article type or publishing date, but article language was limited to only English. Conclusion: The pectoralis muscle is an important muscle when it comes to function of the upper extremity primarily or through transfer procedure. Injuries and impairments of the pectoralis major or other muscles of the upper extremity can significantly impact an individual's quality of life, limiting their ability to perform activities of daily living. A thorough understanding of anatomical, functional, and surgical purposes of the pectoralis muscle is crucial for achieving optimal outcomes and avoiding complications.

Upper Extremity Arteriovenous Malformation Masquerading as a Biceps Ganglion Cyst.

A 71-year-old male presented to the clinic with two multiloculated cystic masses located over the distal bicep of his left upper extremity, causing discomfort when flexing the extremity. Referral and point-of-care ultrasound at an outside location suggested cystic masses that were consistent with that of a ganglion cyst. Physical exam and clinical presentation were also consistent with this diagnosis. Due to the patient's symptomatic presentation, surgical intervention was proposed, and the patient consented. Intraoperatively, it was discovered that the patient's mass was unexpectedly due to an arteriovenous malformation, revealing the importance of careful workup for cystic masses presenting in unusual locations.

Metallosis in Total Hip Arthroplasty.

¼ Metallosis is a rare but significant complication that can occur after total hip arthroplasty (THA) for a variety of reasons but most commonly in patients with metal-on-metal implants.¼ It is characterized by the visible staining, necrosis, and fibrosis of the periprosthetic soft tissues, along with the variable presence of aseptic cysts and solid soft tissue masses called pseudotumors secondary to the corrosion and deposition of metal debris.¼ Metallosis can present with a spectrum of complications ranging from pain and inflammation to more severe symptoms such as osteolysis, soft tissue damage, and pseudotumor formation.¼ Workup of metallosis includes a clinical evaluation of the patient's symptoms, imaging studies, serum metal-ion levels, and intraoperative visualization of the staining of tissues. Inflammatory markers such as erythrocyte sedimentation rate and C-reactive protein along with intraoperative frozen slice analysis may be useful in certain cases to rule out concurrent periprosthetic joint infection.¼ Management depends on the severity and extent of the condition; however, revision THA is often required to prevent rapid progression of bone loss and tissue necrosis.

Peripheral Arterial Disease and Prosthetic Joint Infection Resulting in Hip Disarticulation: A Case Report.

Introduction: The aim of this study was to report a patient with refractory prosthetic joint infection (PJI) and severe peripheral arterial disease that necessitated hip disarticulation (HD), a rare and aggressive procedure. While this is not the first HD performed due to PJI, this is the first reported incidence that deals with profound infection burden along with immense vascular disease that has failed all other treatment options. Case Report: We report a case of an elderly patient with a prior history of the left total hip arthroplasty, PJI, and severe peripheral arterial disease who underwent a rare HD procedure and was discharged with minimal complications. Before this major surgery, several surgical revisions and antibiotic regimens were attempted. The patient had also failed a revascularization procedure to treat an occlusion stemming from the peripheral arterial disease and had developed a necrotic wound at the surgical site. Irrigation and debridement of associated necrotic tissue was unsuccessful and due to concerns such as cellulitis, HD was performed with patient consent. Conclusion: HD is a rare procedure that comprises only 1-3% of all lower limb amputations and is reserved for extremely deleterious indications such as infection, ischemia, and trauma. Complication and 5 year mortality rates have been reported to be as high as 60% and 55%, respectively. Despite these rates, the patient case illustrates a situation, in which early detection of indications for HD prevented further negative outcomes. Based on this case, we believe that HD is a reasonable treatment of choice in patients with severe peripheral arterial disease who fail revascularization and prior moderate treatment options. However, the limited availability of data involving HD and variety of comorbid conditions necessitate further analysis in terms of outcomes.

Does Fibular Displacement Predict Tibial Malrotation in Simulated Tibia-Fibula Fractures.

INTRODUCTION: Tibial malrotation can occur with medullary nailing of diaphyseal tibial fractures. Fibular alignment has been proposed as a surrogate for axial plane reduction intraoperatively. The purpose of this study was to determine whether fibular alignment is a reliable marker of accurate tibial rotation. METHODS: Deidentified CT scans of 50 patients with normal tibial anatomy were selected. Using ImageJ software, we simulated osteotomies at three sites (proximal third, mid-diaphysis, and distal third). We overlaid adjacent CT slices and rotated them around the central axis of the tibia in 5° increments of external rotation (ER) and internal rotation (IR). At each increment, measurements of fibular overlap (%) were obtained from anteroposterior (AP) and lateral views. To simulate fixation of the fibula, we repeated rotation around the axis of the fibula with and without a simulated medullary implant in the tibia. RESULTS: A total of 50 patients were included. The mean age was 62 years, average BMI was 25.8, and 28 of 50 patients (56%) were male. Earliest loss of fibular contact occurred at 24° ER and 22° IR at the proximal site. Contact was lost at 26° ER and 28° IR on the AP view and 42° ER and 29° IR on the lateral view. The mean fibular contact at each 5° increment was similar for ER and IR. Fibular contact was reduced to 50% at 10 to 15° of rotation in ER and IR at all sites. Tibial canal contact was lost at 24° in both ER and IR around the fibula. With a virtual medullary implant, the mean maximal rotation was 6°. DISCUSSION: Surgeons should be aware that 20° or more of malrotation is likely present when fibular contact is lost during medullary nailing of the tibia. Greater than 50% loss of contact should raise suspicion for malrotation. A fixed fibula and medullary tibial implant theoretically preclude significant tibial malrotation.

Olfactory marker protein is critical for functional maturation of olfactory sensory neurons and development of mother preference.

Survival of many altricial animals critically depends on the sense of smell. Curiously, the olfactory system is rather immature at birth and undergoes a maturation process, which is poorly understood. Using patch-clamp technique on mouse olfactory sensory neurons (OSNs) with a defined odorant receptor, we demonstrate that OSNs exhibit functional maturation during the first month of postnatal life by developing faster response kinetics, higher sensitivity, and most intriguingly, higher selectivity. OSNs expressing mouse odorant receptor 23 (MOR23) are relatively broadly tuned in neonates and become selective detectors for the cognate odorant within 2 weeks. Remarkably, these changes are prevented by genetic ablation of olfactory marker protein (OMP), which is exclusively expressed in mature OSNs. Biochemical and pharmacological evidence suggests that alteration in odorant-induced phosphorylation of signaling proteins underlie some of the OMP(-/-) phenotypes. Furthermore, in a novel behavioral assay in which the mouse pups are given a choice between the biological mother and another unfamiliar lactating female, wild-type pups prefer the biological mother, while OMP knock-out pups fail to show preference. These results reveal that OSNs undergo an OMP-dependent functional maturation process that coincides with early development of the smell function, which is essential for pups to form preference for their mother.

Postnatal experience modulates functional properties of mouse olfactory sensory neurons.

Early experience considerably modulates the organization and function of all sensory systems. In the mammalian olfactory system, deprivation of the sensory inputs via neonatal, unilateral naris closure has been shown to induce structural, molecular and functional changes from the olfactory epithelium to the olfactory bulb and cortex. However, it remains unknown how early experience shapes the functional properties of individual olfactory sensory neurons (OSNs), the primary odor detectors in the nose. To address this question, we examined the odorant response properties of mouse OSNs in both the closed and open nostril after 4 weeks of unilateral naris closure, with age-matched untreated animals as control. Using a patch-clamp technique on genetically tagged OSNs with defined odorant receptors (ORs), we found that sensory deprivation increased the sensitivity of MOR23 neurons in the closed side, whereas overexposure caused the opposite effect in the open side. We next analyzed the response properties, including rise time, decay time, and adaptation, induced by repeated stimulation in MOR23 and M71 neurons. Even though these two types of neuron showed distinct properties with regard to dynamic range and response kinetics, sensory deprivation significantly slowed down the decay phase of odorant-induced transduction events in both types. Using western blotting and antibody staining, we confirmed the upregulation of several signaling proteins in the closed side as compared with the open side. This study suggests that early experience modulates the functional properties of OSNs, probably by modifying the signal transduction cascade.