Sean T. Campbell

The Optimum Tension for Bridging Sutures in Transosseous-Equivalent Rotator Cuff Repair A Cadaveric Biomechanical Study

Background: Transosseous-equivalent (TOE) rotator cuff repair can increase contact area and contact pressure between the repaired cuff tendon and bony footprint and can show higher ultimate loads to failure and smaller gap formation compared with other repair techniques. However, it has been suggested that medial rotator cuff failure after TOE repair may result from increased bridging suture tension. Purpose: To determine optimum bridging suture tension in TOE repair by evaluating footprint contact and construct failure characteristics at different tensions. Study Design: Controlled laboratory study. Methods: A total of 18 fresh-frozen cadaveric shoulders, randomly divided into 3 groups, were constructed with a TOE configuration using the same medial suture anchor and placing a Tekscan sensing pad between the repaired rotator cuff tendon and footprint. Nine of the 18 shoulders were used to measure footprint contact characteristics. With use of the Tekscan measurement system, the contact pressure and area between the rotator cuff tendon and greater tuberosity were quantified for bridging suture tensions of 60, 90, and 120 N with glenohumeral abduction angles of 0° and 30° and humeral rotation angles of 30° (internal), 0°, and 30° (external). TOE constructs of all 18 shoulders then underwent construct failure testing (cyclic loading and load to failure) to determine the yield load, ultimate load, stiffness, hysteresis, strain, and failure mode at 60 and 120 N of tension. Results: As bridging suture tension increased, contact force, contact pressure, and peak pressure increased significantly at all positions (P < .05 for all). Regarding contact area, no significant differences were found between 90 and 120 N at all positions, although there were significant differences between 60 and 90 N. The construct failure test demonstrated no significant differences in any parameters according to various tensions (P > .05 for all). Conclusion: Increasing bridging suture tension to over 90 N did not improve contact area but did increase contact force and pressure. Bridging suture tension did not significantly affect ultimate failure loads. Clinical Relevance: Considering the risks of overtensioning bridging sutures, it may be clinically more beneficial to keep bridging suture tension below 90 N.

Biomechanical Evaluation of Coracoid Tunnel Size and Location for Coracoclavicular Ligament Reconstruction

PURPOSE The purpose of this study was to determine the effect of coracoid tunnel size and location on the biomechanical characteristics of cortical button fixation for coracoclavicular ligament reconstruction. METHODS Thirteen matched pairs of cadaveric scapulae were used to determine the effects of coracoid tunnel size, and 6 matched pairs were used to determine the effects of coracoid tunnel location. For tunnel size, a 4.5-mm hole was drilled in the base of the coracoid of one scapula and a 6-mm hole was drilled in the contralateral scapula. For tunnel location, 2 holes were drilled: (1) The first group received a hole centered in the coracoid base and a hole 1.5 cm distal from the first, along the axis of the coracoid. (2) The second group received holes that were offset anteromedially from the first set of holes (base eccentric and distal eccentric). A cortical button-suture tape construct was placed through each tunnel, and constructs were then loaded to failure. RESULTS For tunnel size specimens, load at ultimate failure was significantly greater for the 4.5-mm group compared with the 6-mm group (557.6 ± 48.5 N v 466.9 ± 42.2 N, P < .05). For tunnel location, load at ultimate failure was significantly greater for the centered-distal tunnel group compared with the eccentric-distal group (538.1 ± 70.2 N v 381.0 ± 68.6 N, P < .05). CONCLUSIONS A 4.5-mm tunnel in the coracoid provided greater strength for cortical button fixation than a 6-mm tunnel. In the distal coracoid, centered tunnels provided greater strength than eccentric tunnels. CLINICAL RELEVANCE When performing cortical button fixation at the coracoid process for coracoclavicular ligament reconstruction, a 4.5-mm tunnel provides greater fixation strength than a 6-mm tunnel. The base of the coracoid is more forgiving than the distal coracoid regarding location.

The role of pectoralis major and latissimus dorsi muscles in a biomechanical model of massive rotator cuff tear

BACKGROUND Superior migration of the humeral head after massive rotator cuff tear (mRCT) is thought to lead to cuff tear arthropathy. Previous biomechanical studies have demonstrated the ability of the pectoralis major and latissimus dorsi (PM/LD) muscles to resist this migration. This study examined the role of PM/LD muscles on glenohumeral joint forces and acromiohumeral contact pressures in a mRCT model. METHODS Six cadaveric shoulders were tested using a custom shoulder-testing system. Muscle insertions of the rotator cuff, deltoid, and PM/LD were preserved and used for muscle loading. Specimens were tested in 3 different humeral rotation positions at 0° abduction and 2 rotation positions at 60° abduction. Testing was performed for intact specimens, after supraspinatus removal, and after supraspinatus/infraspinatus/teres minor removal. PM/LD were loaded or unloaded to determine their effect. Humeral head kinematics, glenohumeral joint forces, and acromiohumeral contact area and pressure were measured. RESULTS For the mRCT condition at 0° abduction, unloading the PM/LD resulted in superior shift of the humeral head. Acromiohumeral contact pressures were undetectable when the PM/LD were loaded but increased significantly after PM/LD unloading. After mRCT, superior joint forces were increased and compressive forces were decreased compared with intact; loading the PM/LD resolved these abnormal forces in some testing conditions. CONCLUSION In mRCT, the PM and LD muscles are effective in improving glenohumeral kinematics and reducing acromiohumeral pressures. Strengthening or neuromuscular training of this musculature, or both, may delay the progression to cuff tear arthropathy.

The Effect of Applicant Publication Volume on the Orthopaedic Residency Match

BACKGROUND Research is an important factor used in evaluating applicants to orthopaedic training programs. Current reports regarding the publication rate among prospective residents are likely inaccurate. It is unknown whether research productivity is weighted more heavily at programs affiliated with research-driven institutions. OBJECTIVE To establish accurate baseline data on publication rate among matched applicants to orthopaedic residency programs and to compare publication rates between applicants who matched at research-focused institutions and those who matched elsewhere. DESIGN We performed a literature search for each U.S. resident in the 2013-2014 intern class. Number of publications: (1) in total, (2) in orthopaedic journals, and (3) as first/last author were recorded. Publication rate at the top 25 programs (according to medical school and departmental National Institutes of Health [NIH] funding and U.S. News ranking) was compared statistically against all others. RESULTS Average number of publications per intern for all programs was 1.28 ± 0.15. Number of total and first/last author publications was significantly greater for programs affiliated with medical schools and departments in the top 25 for NIH funding, and at schools in the top 25 U.S. News rankings. Publication rate in orthopaedic journals was significantly higher for programs affiliated with departments in the top 25 for NIH funding and at top 25 U.S. News medical schools. CONCLUSIONS The average matched applicant to an orthopaedic residency program publishes in the peer-reviewed literature less frequently than previously reported. Matched applicants at research-focused institutions tended to have more publications than those who matched at other programs.

A Structured Review Instrument Improves the Quality of Orthopaedic Journal Club

OBJECTIVE We asked the following questions: 1. Does the use of an structured review instrument (SRI) at journal club increase presentation quality, as measured objectively by a standardized evaluation rubric? 2. Does SRI use increase the time required to prepare for journal club? 3. Does SRI use positively impact presenter perceptions about confidence while presenting, satisfaction, and journal club effectiveness, as measured by postparticipation surveys? DESIGN A prospective study was designed in which a grading rubric was developed to evaluate journal club presentations. The rubric was applied to 24 presentations at journal clubs prior to introduction of the SRI. An SRI was developed and distributed to journal club participants, who were instructed to use it to prepare for journal club. The grading rubric was then used to assess 25 post-SRI presentations and scores were compared between the pre- and post-SRI groups. Presentations occurred at either trauma, pediatrics, or spine subspecialty journal clubs. Participants were also surveyed regarding time requirements for preparation, perceptions of confidence while presenting, satisfaction, and perceptions of overall club effectiveness. SETTING A single academic center with an orthopaedic surgery residency program. PARTICIPANTS Resident physicians in the department of orthopaedic surgery. RESULTS Mean presentation scores increased from 14.0 ± 5.9 (mean ± standard deviation) to 24.4 ± 5.2 after introduction of the SRI (p < 0.001). Preparation time decreased from a mean of 47 minutes to 40 minutes after SRI introduction (p = 0.22). Perceptions of confidence, satisfaction, and club effectiveness among trainees trended toward more positive responses after SRI introduction (confidence: 63% positive responses pre-SRI vs 72% post-SRI, p = 0.73; satisfaction: 64% vs 91%, p = 0.18; effectiveness: 64% vs 91%, p = 0.19). CONCLUSIONS The use of a structured review instrument to guide presentations at orthopaedic journal club increased presentation quality, and there was no difference in preparation time. There were trends toward improved presenter confidence, satisfaction, and perception of journal club effectiveness. SRI utilization at orthopaedic journal club may be an effective method for increasing the quality of journal club presentations. Future work should examine the relationship between presentation quality and overall club effectiveness.

What Makes Journal Club Effective?-A Survey of Orthopaedic Residents and Faculty

BACKGROUND Journal clubs play an important role in the education of orthopaedic surgery residents; however, there are sparse data available on the characteristics that make journal clubs effective. OBJECTIVE The primary goal of this study was to determine the characteristics of effective journal clubs as identified by orthopaedic residents and faculty. We sought to compare the opinions of residents and faculty in order to identify areas that may benefit from future research and discussion. DESIGN Orthopaedic surgery residents and faculty at residency programs around the country were surveyed anonymously. The survey was designed to determine the contribution of various journal club characteristics on the effectiveness of journal club. Nonparametric statistics were used to test for goodness-of-fit, and to compare responses between faculty and residents. RESULTS A total of 204 individuals participated. The most important goals of journal clubs were teaching the skillset of evaluating scientific papers (2.0 ± 1.2 [mean rank ± standard deviation, on a scale of 6, with 1 being most important]), encouraging participants to read current orthopaedic literature, (2.4 ± 1.1), and instilling career-long habits of reading the orthopaedic literature among residents (3.1 ± 1.3). Mandatory attendance (71.8%), monthly journal clubs (80.9%), resident presentation of articles (86.7%), and discussion of 3 to 5 papers (78.7%) were thought to lead to more effective clubs. The most clinically relevant articles published within the last year (63.8%), and classic articles that have influenced practice (68.1%) were preferred. Participation and attendance (2.4 ± 1.5) and paper selection (2.6 ± 1.5) were the most important characteristics overall. CONCLUSIONS In orthopaedics, journal clubs fulfill the role of encouraging reading of the literature, as well as educating residents and faculty. There are many possible club formats, but some are clearly felt to be more effective. Particular attention should be paid to attendance, participation, and paper selection.

Are factor Xa inhibitors effective thromboprophylaxis following hip fracture surgery?: A large national database study

INTRODUCTION The purpose of this study was to evaluate the effectiveness of Factor Xa inhibitors (XaI) for thromboprophylaxis following hip fracture surgery in a large cohort of patients, and compare XaI against warfarin and enoxaparin. METHODS Patients undergoing hip fracture surgery from 2007 to 2015 were identified in a large claims database. Patients prescribed warfarin, XaI, or enoxaparin within 2 weeks of surgery were identified and grouped into cohorts. Medical comorbidities and complication incidences, including deep venous thrombosis (DVT), pulmonary embolism (PE), and bleeding complications were calculated. Chi-square analysis was performed and adjusted residuals calculated to determine significant differences. RESULTS DVT rates were significantly different between groups at thirty days only (5.03% warfarin, 2.91% XaI, 3.48% enoxaparin, p=0.047). PE rates were significantly different at all time points; enoxaparin had the lowest rates. There were no differences in the rates of other complications. DISCUSSION XaI are an option for thromboprophylaxis in hip fracture patients, although their possible decreased effectiveness against PE compared to enoxaparin should be considered. CONCLUSIONS This study compares the effectiveness of Factor Xa inhibitors to warfarin and enoxaparin for hip fracture patients, using a large national database. In this study, Factor Xa inhibitors had similar effectiveness for DVT prophylaxis compared to these agents.

Effect of Graft Shape in Lateral Column Lengthening on Tarsal Bone Position and Subtalar and Talonavicular Contact Pressure in a Cadaveric Flatfoot Model

Background: Lateral column lengthening (LCL) has been used for correction of flatfoot deformity. The purpose of this study was to determine the effect of LCL graft shape on tarsal bone position and talonavicular and subtalar joint pressure. Methods: A flatfoot model was created in 6 cadaveric specimens. Corrective LCL was performed using a rectangular graft or a trapezoidal graft with the broad surface oriented dorsally, laterally, or plantarly. Bony surface markers were digitized to calculate angular parameters used in the evaluation of flatfoot deformity. Contact pressure and area in the subtalar and talonavicular joints were also recorded. All measurements were carried out under multiple axial loads in the intact and flatfoot conditions, and following LCL with each graft shape. Results: Flatfoot creation resulted in significant changes in arch collapse and forefoot abduction. LCL with a rectangular graft best corrected these parameters, while a laterally oriented trapezoidal graft provided some correction. Talonavicular contact pressure was unchanged after flatfoot creation, and was significantly less than intact after LCL. Subtalar contact pressure decreased in some conditions after flatfoot creation, and decreased further after LCL. Conclusion: LCL with a rectangular graft best restored tarsal bone orientation in a cadaveric flatfoot model. The decreases in talonavicular pressure likely represent redistribution of force from the medial to lateral foot. Clinical Relevance: When performing LCL for flatfoot deformity, increased bone graft volume medially better restores tarsal bone position. One way of achieving this is through the use of a rectangular graft as opposed to a trapezoidal graft.