Kerwyn C. Jones

Gene expression differences between ruptured anterior cruciate ligaments in young male and female subjects.

BACKGROUND The incidence of anterior cruciate ligament (ACL) injuries is two to eightfold greater in female compared with male athletes. Anatomic, hormonal, and neuromuscular factors have been associated with this disparity. This study compared gene expression and structural features in ruptured but otherwise normal ACL tissue from young female and male athletes. METHODS A biopsy sample of ruptured ACL tissue (which would normally have been discarded) was obtained intraoperatively from seven female and seven male athletes (12.7 to 22.6 years old). Each sample was divided into portions for histological and gene expression analyses. Specimens for gene analysis were frozen and ground, and RNA was extracted and purified. Microarray analysis was performed on RNA isolated from four female and three male study participants (13.9 to 18.5 years old) who had a noncontact injury. Genes with an expression level that differed significantly between these female and male athletes were grouped into functionally associated networks with use of IPA software (Qiagen). Three genes of interest were chosen for further validation by RT-qPCR (reverse transcription-quantitative polymerase chain reaction) analysis of the samples from all fourteen patients. Several statistical methods were used to examine sex-related differences. RESULTS Microarray analysis of the RNA isolated from the ruptured ACL tissue from the female and male athletes identified thirty-two genes with significant differential expression. Fourteen of these genes were not linked to the X or Y chromosome. IPA analysis grouped these genes into pathways involving development and function of skeletal muscle and growth, maintenance, and proliferation of cells. RT-qPCR confirmed significant differences in expression of three selected genes: ACAN (aggrecan) and FMOD (fibromodulin) were upregulated in female compared with male study participants, and WISP2 (WNT1 inducible signaling pathway protein 2) was downregulated. No morphological differences among the ruptured tissue from the various participants were apparent on histological examination. CONCLUSIONS The genes identified in this study as differing distinctly according to sex produce major molecules in the ACL extracellular matrix. Significant upregulation of ACAN and FMOD (which regulate the matrix) and downregulation of WISP2 (which is involved in collagen turnover and production) may account for the weaker ACLs in female compared with male individuals.

All-epiphyseal ACL reconstruction improves tibiofemoral contact: An in vitro study

Background: Anterior cruciate ligament (ACL) injury alters tibiofemoral contact during function, with a posterior shift of the point of contact on the tibia. An all-epiphyseal approach to ACL reconstruction is performed in pediatric patients to improve tibiofemoral contact without disturbing the physis. The hypothesis of the study is that all-epiphyseal ACL reconstruction will shift contact anteriorly on the tibia, as compared with the ACL-deficient knee. Methods: Ten cadaver knees were tested with the ACL cut and with an all-epiphyseal reconstruction. The knees were set at multiple flexion angles (0, 15, 30, and 45 degrees) and loaded with a quadriceps force of 596 N in combination with an anterior force of 100 N, with the quadriceps loaded in isolation, and with the quadriceps loaded in combination with a hamstrings force of 200 N. Sensors under the menisci characterized the center of force on the tibia. Paired t tests were used to identify significant (P<0.05) differences between the reconstructed and cut conditions for all loading conditions at all flexion angles. Results: On the medial plateau, the average center of force was 2 to 5 mm more anterior for the reconstructed condition than for the ACL cut, with the difference significant for all test conditions. The largest differences between the ACL conditions occurred for the combination of quadriceps forces plus an anterior force. On the lateral plateau, the anterior shift in the center of force from the ACL cut to reconstructed condition was significant for all flexion angles except 0 degree for all loading conditions, with an average difference of approximately 2 mm for all significant differences. Conclusions: All-epiphyseal ACL reconstruction shifts contact anteriorly on the tibia compared with the injured knee. Clinical Relevance: The anterior shift of contact on the femur related to all-epiphyseal ACL reconstruction reduces changes related to ACL injury, which could reduce the risk of cartilage damage and meniscal injuries without violating the growth plate in pediatric patients.

The impact of a daily pre-operative surgical huddle on interruptions, delays, and surgeon satisfaction in an orthopedic operating room: a prospective study

BackgroundThe goal of this project was to implement a daily pre-operative huddle (briefing) for orthopedic cases and evaluate the impact of the daily huddle on surgeons’ perceptions of interruptions and operative delays.MethodsBaseline measurements on interruptions, delays, and questions were obtained. Then the daily pre-operative huddle was introduced. Surgeons completed a surgical outcomes worksheet for each day’s cases. Outcomes evaluated were primarily interruptions and delays starting cases before and following introduction of the huddle.Results19 baseline observations and 19 huddle-implemented observations of surgeon’s days were assessed. Overall, surgeon satisfaction increased and fewer delays occurred after introduction of huddles. Interruptions decreased in all categories including equipment, antibiotics, planned procedure and side. Time required for a huddle was less than one minute per case.ConclusionsIn this pilot study, a daily pre-operative huddle improved the flow of a surgeon’s day and satisfaction and indirectly provided indications of safety benefits by decreasing the number of interruptions and delays. Further studies in other surgical specialties should be conducted due to the promising results. Data was collected from three orthopedic surgeons in this phase; however, as a next step, data should be drawn from the rest of the orthopedic surgical team and other surgical subspecialties as well.

Management of the Rigid Cavus Foot in Children and Adolescents

This article reviews historical approaches to the various osteotomies in the treatment of rigid cavus feet in children, with an emphasis on the biplanar nature of historical osteotomies. The Akron dome midfoot osteotomy is performed at the apex of the rigid cavus deformity and allows for maximum correction in any plane, and for varus, valgus, dorsal, plantar, and rotational correction. In that regard, the Akron dome midfoot osteotomy provides the greatest amount of multiplanar correction. It does not, however, provide correction of hindfoot deformities or deformity distal to the neck of the metatarsal.

Pediatric Orthopaedic Workforce in 2014: Current Workforce and Projections for the Future

Background: The changing nature of the United States (US) health care system has prompted debate concerning the physician supply. The basic questions are: do we have an adequate number of surgeons to meet current demands and are we training the correct number of surgeons to meet future demands? The purpose of this analysis was to characterize the current pediatric orthopaedic workforce in terms of supply and demand, both present and future. Methods: Databases were searched (POSNA, SF Match, KID, MGMA) to determine the current pediatric orthopaedic workforce and workforce distribution, as well as pediatric orthopaedic demand. Results: The number of active Pediatric Orthopaedic Society of North America (POSNA) members increased over the past 20 years, from 410 in 1993 to 653 in 2014 (155% increase); however, the density of POSNA members is not equally distributed, but correlates to population density. The number of estimated pediatric discharges, orthopaedic and nonorthopaedic, has remained relatively stable from 6,348,537 in 1997 to 5,850,184 in 2012. Between 2003 and 2013, the number of pediatric orthopaedic fellows graduating from Accreditation Council for Graduate Medical Education and non-Accreditation Council for Graduate Medical Education programs increased from 39 to 50 (29%), with a peak of 67 fellows (71%) in 2009. Discussion: Although predicting the exact need for pediatric orthopaedic surgeons (POS) is impossible because of the complex interplay among macroeconomic, governmental, insurance, and local factors, some trends were identified: the supply of POS has increased, which may offset the expected numbers of experienced surgeons who will be leaving the workforce in the next 10 to 15 years; macroeconomic factors influencing demand for physician services, driven by gross domestic product and population growth, are expected to be stable in the near future; expansion of the scope of practice for POS is expected to continue; and further similar assessments are warranted. Level of Evidence: Level II—economic and decision analysis.

Dynamic tracking influenced by anatomy following medial patellofemoral ligament reconstruction: Computational simulation

BACKGROUND Continued patellar instability can occur following medial patellofemoral ligament (MPFL) reconstruction. Computational simulation of function was used to investigate the influence of the lateral position of the tibial tuberosity, trochlear dysplasia and patella alta on lateral patellar tracking following MPFL reconstruction. METHODS Multibody dynamic simulation models were developed to represent nine knees being treated for recurrent patellar instability. Knee extension against gravity and dual limb squatting were simulated with and without simulated MPFL reconstruction. Graft resting lengths were set to allow 10mm and five millimeters of patellar lateral translation at 30° of knee flexion. The bisect offset index, lateral tibial tuberosity to posterior cruciate ligament tibial attachment (TT-PCL) distance, lateral trochlear inclination, and Caton-Deschamps index were quantified at every five degrees of knee flexion to characterize lateral tracking, lateral position of the tibial tuberosity, trochlear dysplasia, and patella alta, respectively. For the pre-operative and post-operative conditions and each type of motion, bisect offset index was correlated with the anatomical parameters using stepwise multivariate linear regression. RESULTS For both motions, the pre-operative and post-operative bisect offset indices were significantly correlated with lateral trochlear inclination and lateral TT-PCL distance. For both motions, the adjusted r2 decreased with MPFL reconstruction, but was still approximately 0.5 for MPFL reconstruction allowing five millimeters of lateral translation. CONCLUSION MPFL reconstruction decreases but does not eliminate lateral maltracking related to trochlear dysplasia and a lateralized tibial tuberosity. Patients with these pathologies are likely at the highest risk for instability related to maltracking following MPFL reconstruction.

Variations in Tibial Tuberosity to Trochlear Groove and Posterior Cruciate Ligament Distances due to Tibial External and Valgus Rotations

Abstract Tibial rotations with respect to the femur influence measurements used to assess the lateral position of the tibial tuberosity. This study utilized computational modeling to quantify how the tibial tuberosity to trochlear groove (TT‐TG) and tibial tuberosity to posterior cruciate ligament attachment (TT‐PCL) distances vary with tibial internal/external and varus/valgus rotations. Computational models were developed from magnetic resonance imaging data to represent eight knees with patellar instability. TT‐TG and TT‐PCL distances were quantified from the computational models for a neutral orientation and with the tibia rotated internally and externally and into varus and valgus in 1‐degree increments to 5 degrees. Regression analyses related tibial rotations to TT‐TG and TT‐PCL distances. TT‐TG distance increased with tibial external rotation, and both TT‐TG and TT‐PCL distances increased with valgus orientation (r2 > 0.94 for all regressions). The average increase in TT‐TG distance for each 1 degree of tibial external rotation was 0.55 mm (range: 0.50‐0.62 mm), compared with 0.00 mm (range: −0.05 to 0.04 mm) for TT‐PCL distance. The average increase in TT‐TG distance for each 1 degree of valgus was 1.01 mm (range: 0.91‐1.14 mm), compared with 0.46 mm (range: 0.32‐0.60 mm) for TT‐PCL distance. TT‐TG distance varies more with tibial rotations than TT‐PCL distance due to both points being on the tibia and a smaller proximal‐distal distance between the points for TT‐PCL distance.

Computational simulation of medial versus anteromedial tibial tuberosity transfer for patellar instability: SIMULATION OF TIBIAL TUBEROSITY MEDIALIZATION

The study utilizes dynamic simulation of knee function to determine how tibial tuberosity medialization and anteromedialization influence patellar tracking and contact pressures for knees with patellar instability. Dual limb squatting was simulated with six multibody dynamic simulation models representing knees being treated for patellar instability. Each knee exhibited lateral patellar maltracking in the pre‐operative condition based on the bisect offset index. The patellar tendon attachment points on the tibia were medialized by 10 mm to represent tibial tuberosity medialization, with an additional 5 mm of anteriorization applied for anteromedialization. The patellofemoral contact pressure distribution was quantified using discrete element analysis. Data were analyzed with repeated measures analysis of variance with post‐hoc tests and linear regressions. Tibial tuberosity medialization and anteromedialization significantly (p < 0.05) decreased the bisect offset index for nearly all flexion angles up to 80°, with the largest changes near full extension. Both procedures significantly decreased the maximum lateral pressure at 55°, but increased the maximum medial pressure from 30 to 80°. The pre‐operative to post‐operative increase in the maximum contact pressure was significantly correlated with the maximum pre‐operative bisect offset index for tuberosity medialization (r2 = 0.84), but not for anteromedialization. Statement of Clinical Significance: The results indicate tibial tuberosity medialization decreases patellar lateral maltracking and lateral patellofemoral contact pressures, but increases medial contact pressures. When pre‐operative patellar maltracking is relatively low, tibial tuberosity medialization is likely to increase maximum contact pressures. Tibial tuberosity anteromedialization lowers the risk of elevated post‐operative contact pressures compared to medialization.

College Athletes’ Perception of Anterior Cruciate Ligament Injuries and Subsequent Reconstruction

Objectives: Anterior cruciate ligament (ACL) tears are one of the most common ligamentous injuries of the knee. While many advances have been made in both surgical technique and rehabilitation protocols, it still remains a very serious athletic injury. In recent years, a few high-profile athletes have returned to an elite sport performance level relatively quickly after ACL reconstruction, but previously published literature suggests otherwise. The purpose of this study is to evaluate a college athletes perception and understanding of ACL injury and subsequent reconstruction. Methods: During pre-participation physicals, a total of 157 surveys were prospectively administered to athletes at a single NCAA Division II university, all of which were returned. Consent was obtained prior to survey administration. The surveys, consisting of sixteen questions, were designed to evaluate the athletes’ knowledge of ACL injury, anatomy, and recovery from surgery. In addition, basic demographic information was obtained including the participants’ source of ACL knowledge. Statistical analysis is pending. Results: The average age of participants was 20.1 years (Range: 18-23). Football, soccer and baseball were the most represented sports among participants, but a wide variety were present. Of the 157 surveys administered, 106 of participants (68%) knew that the ACL was a ligament. The majority of participants (63%) thought it would take 8-12 months to return to sport after an injury, but 31% said an athlete could return in less than 6 months (Range: 2 to 15 months). On average, the participants thought 64% of athletes could return to play in their sport after an ACL injury and reconstruction, but only 45% could return to their previous level of play. However, several participants (8%) believed greater than 80% of athletes could return to their previous level of play after an ACL reconstruction. Only 11% of respondents knew that a knee brace cannot prevent ACL injury. Most participants (82%) said that if they had an ACL injury they would undergo reconstructive surgery. Only 26% of participants knew that an athlete with an ACL injury was at an increased risk for an injury to their contralateral ACL. Furthermore, about half of the participants (54%) thought that on-field performance would not improve following an ACL injury and reconstruction. The most common source of participants’ knowledge of ACL injury was from a friend or family member (71%). Far fewer participants gained at least some of their knowledge from the internet (32%), television (27%) or their physician/surgeon (29%). Conclusion: This is the first study, to our knowledge, to assess the perceptions of high-level athletes with regards to ACL injury, reconstruction and return to play. This study demonstrates that there is a large amount of variability in college athletes’ perception of ACL injuries. The range of recovery time from surgery was quite large, signifying a knowledge gap among high-level athletes with regard to this very common injury. Orthopaedic surgeons may want to assess and tailor their pre-surgical discussions with a college athlete to the individuals knowledge of ACL injury and reconstructions, so that realistic pre-surgical expectations are set. However, the benefits of this approach warrant further investigation.

Limited benefit of hamstrings forces for the anterior cruciate ligament-deficient knee: an in vitro study.

The hamstrings are considered stabilizers of the anterior cruciate ligament-deficient knee; however, anterior cruciate ligament injury primarily influences tibiofemoral kinematics near full extension, where the hamstrings have the least influence on kinematics. Ten knees were tested at multiple flexion angles in vitro to directly compare the influence of anterior cruciate ligament injury and hamstrings activation on tibiofemoral kinematics. Tibiofemoral kinematics were measured for three testing conditions: (1) anterior cruciate ligament intact, with forces applied through the quadriceps muscles (596 N), (2) anterior cruciate ligament cut, with forces applied through the quadriceps, and (3) anterior cruciate ligament cut, with forces applied through the quadriceps and hamstrings (200 N). Based on repeated measures comparisons performed at each flexion angle, cutting the anterior cruciate ligament significantly (p < 0.05) increased tibial anterior translation, medial translation, and internal rotation at 0° and 15° of flexion by approximately 2.5 mm, 1 mm, and 2°, respectively. Internal rotation also increased significantly at 30°. With the anterior cruciate ligament cut, loading the hamstrings significantly decreased anterior translation, medial translation, and internal rotation at 45°, by approximately 2 mm, 2 mm, and 4°, respectively. Loading the hamstrings caused kinematic changes in the opposite direction of the anterior cruciate ligament injury, but the changes occurred at deeper flexion angles than those at which anterior cruciate ligament injury influenced tibiofemoral kinematics.