Six Percent Incidence of Graft-Tunnel Mismatch in Anatomic Anterior Cruciate Ligament Reconstruction Using Bone-Patella Tendon-Bone Autograft and Anteromedial Portal Drilling.

Purpose: The purpose of this study was to determine the incidence of graft-tunnel mismatch (GTM) when performing anatomic anterior cruciate ligament reconstruction (ACLR) using bone-patella tendon-bone (BPTB) grafts and anteromedial portal drilling. Methods: Beginning in November 2018, 100 consecutive patients who underwent ACLR by two sports fellowship-trained, orthopedic surgeons using BPTB autograft and anteromedial portal drilling were prospectively identified. The BPTB graft dimensions and the femoral tunnel distance, tibial tunnel distance, intra-articular distance, and total distance were measured. Surgeons determined the depth and angle of tunnels based on the patella tendon graft length dimensions in each case. After passage of the graft, the distance from the distal graft tip to the tibial cortex aperture was measured. GTM was defined as the need for additional measures to obtain satisfactory tibial graft fixation (<15-20 mm of bone fixation). Results: The incidence of mismatch was 6/100 (6%). Five cases involved the graft being too long, with the tibial bone plug protruding excessively from the tibial tunnel-4/5 had a patella tendon length ≥ 50 mm. Three cases were managed with femoral tunnel recession, and two were treated with a free bone plug technique. One patient with a patella tendon length of 35 mm had a graft that was too short, with the tibial bone plug recessed in the tibial tunnel. Of patients whose tibial tunnel distance was within 5 mm of the patella tendon length, only 1/46 (2%) patients had mismatch, whereas 5/54 (9%) of patients who had >5 mm difference had mismatch. Conclusions: The incidence of graft-tunnel mismatch after anatomic ACLR using BTPB and anteromedial portal drilling in this study is 6%. To limit the occurrence of GTM where the graft is too long, surgeons should drill tibial tunnel distances within 5 mm of the patella tendon length. Clinical Relevance: The results of this study provide surgeons with a technique of limiting graft tunnel mismatch when performing ACLR using BPTB and anteromedial portal drilling.

Valgus stress radiography following superficial medial collateral ligament reconstruction using a modified LaPrade technique with adjustable loop femoral fixation.

Purpose of this study was to assess postoperative laxity of MCL reconstructions utilizing a modified LaPrade superficial MCL reconstruction. We retrospectively reviewed post-operative valgus stress radiographs in 23 multiligament injured patients who underwent concurrent sMCL and cruciate ligament reconstruction by a single surgeon. Post- operatively, 23 patients underwent valgus stress radiographs that were assessed at a mean of 8.7 months (range: 4-13 months), and mean SSD was 0.64mm ± 0.42mm. Eight patients underwent both pre- and post-operative valgus stress radiographs. Post-operative (0.09mm ± 0.63mm) SSD was found to be significantly reduced compared to pre-operative (2.07mm ± 0.44mm) SSD (mean diff. = 1.98mm, 95% CI = 0.72-3.24, P=0.007). Inter-observer reliability value for medial compartment gap measurement was 0.91 with a 95% confidence interval of 0.34- 0.97. In conclusion, presented technique results in excellent static stability of the knee as measured by valgus stress radiography at a minimum of 6 months postoperative. Level of Evidence: IV.

Short Versus Long InterTAN Fixation for Geriatric Intertrochanteric Hip Fractures: A Multicentre Head-to-Head Comparison.

OBJECTIVE: To determine if geriatric intertrochanteric hip fracture patients achieve equivalent postoperative functional status after management with either a short (180-200 mm) or a long (260-460 mm) InterTAN intramedullary device. DESIGN: Retrospective review of a prospective randomized control trial. SETTING: Four Level I Trauma Centers. PATIENTS/PARTICIPANTS: One hundred eight patients with OTA/AO classification 31A-1 and 31A-2 intertrochanteric hip fractures were included in the study. INTERVENTION: Internal fixation using an IT device. MAIN OUTCOMES MEASURES: Primary outcomes included Functional Independence Measure and Timed Up and Go. Secondary outcomes included blood loss, surgical time, length of stay, adverse events, and mortality. RESULTS: Seventy-one short and 37 long IT patients met study inclusion criteria. Demographics were similar between groups. There was no difference in Functional Independence Measure or Timed Up and Go scores between the 2 IT groups at any of the time points collected. Mean operative time was lower in the short IT group than in the long IT group (60 vs. 73 minutes; P = 0.021). A higher proportion of long IT patients had reamed constructs (95% vs. 48% short IT, P < 0.001). Postoperative blood loss was significantly higher in the long IT group without a significant influence on the number of patients requiring transfusion (P = 0.582) or average units transfused (P = 0.982). There was no significant difference in the proportion of postoperative adverse events between the 2 cohorts despite a higher number of peri-implant femur fractures in the short IT group than in the long IT group (5 vs. 1, P = 0.350). CONCLUSIONS: Postoperative functional status was not influenced by the length of IT device in the management of geriatric intertrochanteric hip fractures. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Does Time to Surgery Affect Outcomes for Periprosthetic Femur Fractures?

BACKGROUND: Periprosthetic femur fractures around total hip (THA) and total knee (TKA) arthroplasties are difficult complications to manage. With native hip fractures, delay to fixation has been correlated with an increase in postoperative mortality. The effect of time to definitive fixation of periprosthetic femur fractures around THA and TKA is not well established. The aim of our study is to evaluate the effect of time to definitive fixation on postoperative length of stay and mortality for patients with periprosthetic femur fractures around THA and TKA. METHODS: A review of 2537 arthroplasty patient charts yielded 235 patients who were diagnosed with a periprosthetic femur fracture at our institution from 2005 to 2014. Time to surgical management, length of stay, demographics, referral status, fracture classification, and fixation modality along with mortality was recorded for all patients. RESULTS: One hundred eighty patients met study inclusion (111 THAs, 69 TKAs). Average age was 79.2 years and 72.2% were female. The average time from admission to definitive fixation was 96.5 hours with 31.1% of patients having surgery within 48 hours after presenting to hospital. Postoperative length of stay and mortality were not affected by time to definitive fixation greater than 48 hours for either of the periprosthetic TKA or THA patient cohorts. Postoperative mortality within 1 year was 5.5% for all patients (6.3% THA, 4.3% TKA). CONCLUSION: The timing of fixation of periprosthetic femur fractures does not appear to affect postoperative length of stay or mortality within 1 year.

The impact of proximal femoral morphology on failure strength with a mid-head resection short-stem hip arthroplasty.

Mid-head resection short-stem hip arthroplasty is a conservative alternative to conventional total hip replacement and addresses proximal fixation challenges in patients not suitable for hip resurfacing. It is unclear whether proximal femoral morphology impacts the ultimate failure load of mid-head resection implanted femurs, thus the aim of this study was to investigate the effect of native neck-shaft angle (NSA) and coronal implant alignment on proximal femoral strength. In total, 36 synthetic femurs with two different proximal femoral morphologies were utilized in this study. Of them, 18 femurs with a varus NSA of 120° and 18 femurs with a valgus NSA of 135° were each implanted with a mid-head resection prosthesis. Femurs within the two different femoral morphology groups were divided into three equal coronal implant alignment groups: 10° valgus, 10° varus or neutral alignment. Prepared femurs were tested for stiffness and to failure in axial compression. There was no significant difference in stiffness nor failure load between femurs implanted with valgus-, varus- or neutrally aligned implants in femurs with a NSA of 120° (p = 0.396, p = 0.111, respectively). Femurs implanted in valgus orientation were significantly stiffer and failed at significantly higher loads than those implanted in varus alignment in femurs with a NSA of 135° (p = 0.001, p = 0.007, respectively). A mid-head resection short-stem hip arthroplasty seems less sensitive to clinically relevant variations of coronal implant alignment and may be more forgiving upon implantation in some femoral morphologies, however, a relative valgus component alignment is recommended.

Can fluoroscopy-based computer navigation improve entry point selection for intramedullary nailing of femur fractures?

BACKGROUND: The entry point is crucial to an accurate reduction in femoral nailing. Fluoroscopy-based navigation was developed to aid in reducing femur fractures and selecting entry points. QUESTIONS/PURPOSES: We asked: (1) Can the piriformis fossa (PF) and tip of the greater trochanter (TT) be identified with high reproducibility? (2) What is the range of nonneutral images clinically acceptable for entry point selection? (3) Does navigation improve accuracy and precision of landmarking the TT and PF? And (4) does off-angle fluoroscopy within the acceptable range affect landmark accuracy? METHODS: Three orthopaedic surgeons digitized the PF and TT under direct visualization on 10 cadaveric femurs, quantifying the reproducibility of the targeted PF and TT landmarks. Arcs of acceptable AP and lateral images of each femur were acquired in increments of 5° with a C-arm. An experienced orthopaedic surgeon rejected or accepted images for entry point selection by qualitatively assessing the relative positions and sizes of the greater trochanter, lesser trochanter, and femoral neck. Entry points were identified on each image using fluoroscopy and navigation. Hierarchical linear modeling was used to compare accuracy and precision between navigation and fluoroscopy and the effects of image angle. RESULTS: A 29° average arc of acceptable images was found. Reproducibility of the target landmarks for the PF and TT under direct visualization was excellent. Navigation had similar accuracy to fluoroscopy for PF localization but less for TT. Navigation increased precision compared to fluoroscopy for both PF and TT. Image angle affected accuracy of the PF and TT under fluoroscopy and navigation. CONCLUSIONS: Nonorthogonal images reduce accuracy of PF and TT identification with both navigation and fluoroscopy. Navigation increased precision but decreased accuracy and cannot overcome inaccuracies induced by nonorthogonal images.

Evaluation of a patient specific femoral alignment guide for hip resurfacing.

A novel alternative to conventional instrumentation for femoral component insertion in hip resurfacing is a patient specific, computed tomography based femoral alignment guide. A benchside study using cadaveric femora was performed comparing a custom alignment guide to conventional instrumentation and computer navigation. A clinical series of twenty-five hip resurfacings utilizing a custom alignment guide was conducted by three surgeons experienced in hip resurfacing. Using cadaveric femora, the custom guide was comparable to conventional instrumentation with computer navigation proving superior to both. Clinical femoral component alignment accuracy was 3.7° and measured within ± 5° of plan in 20 of 24 cases. Patient specific femoral alignment guides provide a satisfactory level of accuracy and may be a better alternative to conventional instrumentation for initial femoral guidewire placement in hip resurfacing.

Computer navigation vs extramedullary guide for sagittal alignment of tibial components: radiographic study and meta-analysis.

Sagittal alignment of tibial components using computer navigation was compared with conventional methods. A radiologic study was performed using 110 total knee arthroplasties from 3 groups: computer navigation, cutting block with extramedullary guide, and manual tilt of extramedullary guide. Posterior tibial slopes were measured from radiographs and compared using statistical methods. The cutting block method was the most accurate, and computer navigation was the most precise. The manual tilt group had the greatest variance, significantly greater than computer navigation. There was no significant difference between groups with respect to the percentage of knees with posterior slope within 3° of the desired slope. Meta-analysis of 10 studies found no reduction in outliers with computer navigation. Computer navigation offers greatest precision but does not reduce the number of outliers.

Hip resurfacing versus metal-on-metal total hip arthroplasty - are metal ion levels different?

A systematic review and meta-analysis of trials comparing hip resurfacing to metal-on-metal total hip arthroplasty was conducted to determine if there is a difference in serum metal ion levels in patients receiving these implants. EMBASE and MEDLINE databases were searched from inception to December 2010 for all trials involving the use of these devices. Eligibility for inclusion in the review were studies with 1. comparative trials that were both retrospective and prospective; 2. inclusion of a treatment arm receiving hip resurfacing; 3. inclusion of a treatment arm receiving metal-on-metal total hip arthroplasty; and 4. analysis of chromium and cobalt ions, or either, in patient serum or whole blood at a minimum of 1 year after implantation. The literature search identified 87 potential studies, of which 10 met the inclusion criteria. Pooled mean differences were calculated for serum cobalt and chromium ion levels. Mean differences for serum cobalt and chromium metal ions were not significantly different between hip resurfacing and metal-on-metal total hip arthroplasty patients, although there was a tendency for lower serum cobalt ion levels in patients receiving hip resurfacing. Larger prospective randomized trials are required to better substantiate a difference in metal ion levels occurring between these implants.

Iron overload decreases CaV1.3-dependent L-type Ca2+ currents leading to bradycardia, altered electrical conduction, and atrial fibrillation.

BACKGROUND: Chronic iron overload (CIO) is associated with blood disorders such as thalassemias and hemochromatosis. A major prognostic indicator of survival in patients with CIO is iron-mediated cardiomyopathy characterized by contractile dysfunction and electrical disturbances, including slow heart rate (bradycardia) and heart block. METHODS AND RESULTS: We used a mouse model of CIO to investigate the effects of iron on sinoatrial node (SAN) function. As in humans, CIO reduced heart rate (≈20%) in conscious mice as well as in anesthetized mice with autonomic nervous system blockade and in isolated Langendorff-perfused mouse hearts, suggesting that bradycardia originates from altered intrinsic SAN pacemaker function. Indeed, spontaneous action potential frequencies in SAN myocytes with CIO were reduced in association with decreased L-type Ca(2+) current (I(Ca,L)) densities and positive (rightward) voltage shifts in I(Ca,L) activation. Pacemaker current (I(f)) was not affected by CIO. Because I(Ca,L) in SAN myocytes (as well as in atrial and conducting system myocytes) activates at relatively negative potentials due to the presence of Ca(V)1.3 channels (in addition to Ca(V)1.2 channels), our data suggest that elevated iron preferentially suppresses Ca(V)1.3 channel function. Consistent with this suggestion, CIO reduced Ca(V)1.3 mRNA levels by ≈40% in atrial tissue (containing SAN) and did not lower heart rate in Ca(V)1.3 knockout mice. CIO also induced PR-interval prolongation, heart block, and atrial fibrillation, conditions also seen in Ca(V)1.3 knockout mice. CONCLUSIONS: Our results demonstrate that CIO selectively reduces Ca(V)1.3-mediated I(Ca,L), leading to bradycardia, slowing of electrical conduction, and atrial fibrillation as seen in patients with iron overload.

A biomechanical comparison of epiphyseal versus metaphyseal fixed bone-conserving hip arthroplasty.

BACKGROUND: The Birmingham Mid-Head Resection (BMHR) is a bone-conserving, short-stem alternative to hip resurfacing for patients with abnormal femoral head anatomy. METHODS: The current study examines whether a bone-preserving femoral component that is fixed into the femoral neck metaphysis provides a mechanical advantage in terms of resisting femoral neck fracture in comparison with a conventional hip resurfacing implant in a human cadaveric femoral model. RESULTS: Femora with a BMHR femoral component failed at an average of 23% less load than those prepared with a conventional hip resurfacing component (mean and standard deviation, 5434 ± 2297 compared with 7012 ± 2619 N; p < 0.001). CONCLUSIONS: An uncemented, metaphyseal fixed, bone-conserving femoral implant does not provide superior mechanical strength or increased resistance to femoral neck fracture in comparison with a conventional hip resurfacing arthroplasty.

Insulin and dexamethasone dynamically regulate adipocyte 11beta-hydroxysteroid dehydrogenase type 1.

The adipocyte enzyme 11beta-hydroxysteroid dehydrogenase type 1 (11beta-HSD1) amplifies local glucocorticoid action by generating active glucocorticoids from inactive metabolites and has emerged as a key player in the pathogenesis of central obesity and metabolic syndrome. However, the regulation of adipocyte 11beta-HSD1 is incompletely understood. Therefore, the present study was designed to investigate the effects of insulin and glucocorticoid as well as their underlying molecular mechanisms on 11beta-HSD1 activity and expression in 3T3-L1 adipocytes and determine whether the in vitro findings could be confirmed in vivo. Our main in vitro findings are 1) insulin stimulated whereas dexamethasone inhibited 11beta-HSD1 activity and expression in a time- and concentration-dependent manner; 2) the effect of dexamethasone was mimicked by both cortisol and corticosterone but blocked by the glucocorticoid receptor antagonist RU486; 3) the p38 MAPK inhibitor SB220025, but not the ERK inhibitor U0126 or the phosphatidylinositol 3-kinase inhibitor LY294002, prevented insulin stimulation of 11beta-HSD1 activity; and 4) although dexamethasone did not alter the half-life of 11beta-HSD1 mRNA, insulin doubled it. Taken together, these in vitro results demonstrate that insulin stimulates adipocyte 11beta-HSD1 through a posttranscriptional mechanism that involves activation of the p38 MAPK signaling pathway, whereas dexamethasone exerts an opposite effect by a glucocorticoid receptor-mediated transcriptional mechanism. In contrast, both insulin and dexamethasone augmented 11beta-HSD1 activity and expression in rat white adipose tissue in vivo, thus confirming the role of insulin but revealing a fundamental difference regarding the role of dexamethasone in regulating adipocyte 11beta-HSD1 between the two model systems.