Christopher L. Camp

Medial Patellofemoral Ligament Repair for Recurrent Patellar Dislocation

Background The medial patellofemoral ligament (MPFL) is the primary restraint to extreme lateral displacement and is typically disrupted with an acute lateral patellar dislocation. Patients who fail a comprehensive nonoperative program and experience recurrent lateral patellar instability episodes are candidates for surgical treatment. Current surgical procedures include a variety of proximal realignment techniques, including repair or reconstruction of the MPFL along with distal realignment of the tibial tubercle when indicated. Purpose The objective of this study was to review the clinical, functional, and radiographic outcomes of isolated MPFL repair for recurrent lateral patellar dislocation. Study Design Case series; Level of evidence, 4. Methods The records of all patients undergoing MPFL repair for recurrent patellar dislocation at the Mayo Clinic from 2001 to 2006 were retrospectively reviewed. Twenty-seven patients (29 knees) with an average age of 19 years (range, 11-32 years) were included in this study. Clinical, functional, and radiographic outcomes were assessed at an average of 4 years after surgery (range, 2-7 years), using recurrent instability as the primary end point. Results The success rate of MPFL repair for preventing recurrent dislocations was 72% (21 of 29 knees). Eight patients (28%) experienced a recurrent lateral patellar dislocation. Five of these patients required a reoperation, including two MPFL reconstructions, 1 tibial tubercle osteotomy with MPFL reconstruction, 1 tibial tubercle osteotomy with revision MPFL repair, and 1 revision MPFL repair. At final follow-up, the mean Lysholm and Kujala scores were 86 (range, 42-100) and 92 (range, 57-105), respectively. Postoperative radiographs revealed a mean patellofemoral congruence angle improvement of 27° (range, 5°-44°). The only statistically significant risk factor for failure was nonanatomical MPFL repair at the medial femoral condyle (P = .004). Conclusion Isolated repair of the MPFL for recurrent patellar instability is associated with a relatively high failure rate, but remains a viable surgical option if surgical technique principles are followed. The clinical success of this operation depends on restoration of the anatomical origin of the MPFL and careful patient selection.

Restructuring a basic science course for core competencies: an example from anatomy teaching.

Medical schools revise their curricula in order to develop physicians best skilled to serve the publics needs. To ensure a smooth transition to residency programs, undergraduate medical education is often driven by the six core competencies endorsed by the Accreditation Council for Graduate Medical Education (ACGME): patient care, medical knowledge, practice-based learning, interpersonal skills, professionalism, and systems-based practice. Recent curricular redesign at Mayo Medical School provided an opportunity to restructure anatomy education and integrate radiology with first-year gross and developmental anatomy. The resulting 6-week (120-contact-hour) human structure block provides students with opportunities to learn gross anatomy through dissection, radiologic imaging, and embryologic correlation. We report more than 20 educational interventions from the human structure block that may serve as a model for incorporating the ACGME core competencies into basic science and early medical education. The block emphasizes clinically-oriented anatomy, invites self- and peer-evaluation, provides daily formative feedback through an audience response system, and employs team-based learning. The course includes didactic briefing sessions and roles for students as teachers, leaders, and collaborators. Third-year medical students serve as teaching assistants. With its clinical focus and competency-based design, the human structure block connects basic science with best-practice clinical medicine.

CT and MRI Measurements of Tibial Tubercle–Trochlear Groove Distances Are Not Equivalent in Patients With Patellar Instability

Background: Tibial tubercle–trochlear groove distance (TT-TG) is a commonly used measurement for surgical decision making in patients with patellofemoral malalignment and instability. This measurement has historically been performed utilizing axial computed tomography (CT). More recently, magnetic resonance imaging (MRI) has been proposed as an equivalent method, but this has not yet been fully validated. Purpose: To determine the reliability of TT-TG distance measurements on both MRI and CT and to determine whether the measurements are interchangeable with one another. Study Design: Cohort study (diagnosis); Level of evidence, 2. Methods: All patients with patellar instability who underwent both CT and MRI of the knee from 2003 to 2011 were included (n = 59 knees in 54 patients). Two fellowship-trained musculoskeletal radiologists measured the TT-TG distances for each patient by CT and MRI in a randomized, blinded fashion. Interobserver reliability was calculated between radiologists for both imaging modalities, and intermethod reliability was calculated between the 2 imaging modalities. The results are reported using intraclass correlation coefficients (ICCs) and Bland-Altman analysis. Results: The 59 knees had a mean TT-TG distance of 16.9 mm (range, 8.3-25.8 mm) by CT and 14.7 mm (range, 1.5-25.1 mm) by MRI. Interobserver reliability between the radiologists was considered excellent for both CT and MRI (ICC = 0.777 and 0.843, respectively). When comparing CT to MRI, the ICC was considered only fair for each of the raters (0.532 and 0.539). Eleven patients (19%) had a TT-TG distance of ≥20 mm on CT preoperatively and underwent distal realignment by tibial tubercle osteotomy. In this surgical subgroup, the mean TT-TG distance was 22.5 mm (range, 19.8-25.8 mm) by CT and only 18.7 mm (range, 14.4-22.8 mm) by MRI for a mean difference of 3.80 mm (P < .001). Conclusion: The TT-TG distance can be measured with excellent interrater reliability on both MRI and CT; however, the values derived from these 2 tests may not be interchangeable. This observation should be taken into consideration when MRI is used for surgical planning because MRI may underestimate the TT-TG distance when compared with CT.

Current Concepts of Articular Cartilage Restoration Techniques in the Knee

Context: Articular cartilage injuries are common in patients presenting to surgeons with primary complaints of knee pain or mechanical symptoms. Treatment options include comprehensive nonoperative management, palliative surgery, joint preservation operations, and arthroplasty. Evidence Acquisition: A MEDLINE search on articular cartilage restoration techniques of the knee was conducted to identify outcome studies published from 1993 to 2013. Special emphasis was given to Level 1 and 2 published studies. Study Design: Clinical review. Level of Evidence: Level 3. Results: Current surgical options with documented outcomes in treating chondral injuries in the knee include the following: microfracture, osteochondral autograft transfer, osteochondral allograft transplant, and autologous chondrocyte transplantation. Generally, results are favorable regarding patient satisfaction and return to sport when proper treatment algorithms and surgical techniques are followed, with 52% to 96% of patients demonstrating good to excellent clinical outcomes and 66% to 91% returning to sport at preinjury levels. Conclusion: Clinical, functional, and radiographic outcomes may be improved in the majority of patients with articular cartilage restoration surgery; however, some patients may not fully return to their preinjury activity levels postoperatively. In active and athletic patient populations, biological techniques that restore the articular surface may be options that provide symptom relief and return patients to their prior levels of function.

Comparative Efficacy of Group and Individual Feedback in Gross Anatomy for Promoting Medical Student Professionalism.

Professionalism is a core competency of medical training that requires students to develop the skills of providing and receiving feedback. Our study evaluated the effectiveness of delivering feedback in a group setting compared with an individual setting. The first‐year class of Mayo medical students (n = 49) enrolled in gross anatomy (in dissection teams), completed weekly anonymous evaluations of themselves and their teammates regarding seven aspects of professionalism (altruism, compassion, respect, honesty/integrity, responsibility, commitment to excellence, and self‐reflection). Professionalism scores from these surveys were calculated using a six‐point Likert scale. Students were also asked to comment on strengths and possible areas for improvement on each peer. At the midpoint of the course, peer comments and professionalism scores were shared with students in debriefing sessions either individually or with their team. Analysis of preintervention and postintervention professionalism scores indicated that the students receiving feedback in a one‐on‐one setting (student and instructor) were more likely to demonstrate higher scores on subsequent evaluations as compared with those students receiving feedback in a group setting (all team members and one instructor). Our findings suggest that providing feedback to first‐year medical students on an individual basis is the best way to improve professional attitudes and behaviors. Anat Sci Educ 3: 64–72, 2010.

Attracting Students to Surgical Careers: Preclinical Surgical Experience

OBJECTIVES Along with a decline in interest in general surgery among United States medical school graduates, reports indicate a decrease in the amount of time students are spending on their surgical clerkship. In an effort to offer early exposure to general surgery as well as to equip students with the basic surgical skills that will enhance their third-year clerkship experience, we developed a preclinical surgical experience. Students were surveyed to determine whether the surgical selective changed student level of comfort with basic surgical skills. STUDY DESIGN Surveys were administered, preexperience and postexperience to the medical students enrolled in the surgery selective. The students were asked to rate their comfort level with 12 unique surgical skills. Comfort with the task was evaluated using a 10-point Likert scale. Analyses were conducted to evaluate the impact of the surgical experience on student comfort levels with the surgical skills. RESULTS The self-reported comfort levels of students increased significantly after the experience in all 12 areas. The greatest change in comfort level (greater than or equal to mean difference of 4) occurred in the surgical technique categories: knot tying (mean difference: 4.9, p < 0.0001), suturing (mean difference: 4.85, p < 0.0001), correctly making an incision (mean difference: 4.95, p < 0.0001), using a needle driver (mean difference: 5.35, p < 0.0001), holding pickups (mean difference: 4.6, p < 0.0001), use of laparoscopic instruments (mean difference: 4.8, p < 0.0001), and use of surgical simulators (mean difference: 6.0, p < 0.0001). CONCLUSIONS Our preclinical surgical experience serves as a model of an effective modality providing early exposure to general surgery. The experience provides trainees with basic surgical skills well before they begin their third-year clerkships.

Learning to Lead: Self- and Peer Evaluation of Team Leaders in the Human Structure Didactic Block.

Increasing emphasis on leadership in medical education has created a need for developing accurate evaluations of team leaders. Our study aimed to compare the accuracy of self‐ and peer evaluation of student leaders in the first‐year Human Structure block (integrated gross anatomy, embryology, and radiology). Forty‐nine first‐year medical students at Mayo Medical School were assigned to learning teams of three or four members. Teams worked together on daily laboratory dissection, clinical projects, embryology presentations, and daily group quizzes. Student team leaders were responsible for leading laboratory dissection, reviewing radiographic findings, and organizing group assignments. Weekly electronic surveys were administered to evaluate team leaders on altruism, compassion, respect, integrity, responsibility, commitment to excellence, and self‐reflection. Results demonstrated that team leaders rated themselves lower than their peers rated them in multiple aspects of leadership. Peer evaluation of team leaders was statistically higher than self‐evaluation in all traits measured except respect. Female leaders were rated higher by their peers in the areas of responsibility and self‐reflection compared to male leaders. This study demonstrates the need for increased communication between team leaders and members, along with creation of a mutually respectful environment, to improve leader awareness of their abilities and foster team success. Anat Sci Educ 2:210–217, 2009.

Individualizing the Tibial Tubercle– Trochlear Groove Distance Patellar Instability Ratios That Predict Recurrent Instability

Background: Patients with patellar instability and a tibial tubercle–trochlear groove (TT-TG) distance ≥20 mm may be candidates for distal tubercle realignment surgery. Although this variable has proven valuable in predicting recurrent dislocations, it is not individualized to patient size, bony structure, or patellofemoral mechanics. Purpose: To develop a patellar instability ratio (PIR) that predicts the risk of recurrent instability based on the TT-TG distance to patient-specific anatomy. Study Design: Cohort study; Level of evidence, 3. Methods: On magnetic resonance imaging scans of 59 knees with patellar instability, the TT-TG distance, tibial tubercle–posterior cruciate ligament (TT-PCL) distance, sagittal patellar length (PL), sagittal trochlear length (TL), axial patellar width (PW), and axial trochlear width (TW) were calculated by 2 observers in a blinded and randomized fashion. Patients were divided into 2 groups: those with a single dislocation and those with multiple (≥2) dislocations. The ability of the TT-TG and TT-PCL distances as well as the 8 different ratios to predict recurrent instability was assessed by calculating odds ratios (ORs), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each measure. Results: Twelve knees (20%) experienced a single dislocation, while 47 (80%) sustained multiple dislocations. A TT-TG distance ≥20 mm was predictive of recurrent instability, with a sensitivity, specificity, and PPV of 21%, 100%, and 100%, respectively. The OR for TT-TG ≥20 mm was 5.38 (P = .29), while the highest ORs for recurrent instability were noted for a TT-TG/PW ≥0.4 (OR, 7.37; P = .02) and a TT-TG/TW ≥0.5 (OR, 8.88; P = .04). The sensitivity, specificity, and PPV of a TT-TG/PW ≥0.4 were 62%, 83%, and 94%, respectively, while those of a TT-TG/TW ≥0.5 were 45%, 92%, and 95%, respectively. Conclusion: Two novel PIRs (TT-TG/TW and TT-TG/PW) were identified and found to more effectively predict recurrent instability than the TT-TG distance alone. Each ratio takes into account patient-specific anatomy and can be measured in an accurate and reliable fashion by clinicians. These PIRs are a step toward overcoming some of the limitations of using the TT-TG distance in isolation. Further investigation into the clinical applications and utility of the TT-TG/TW is warranted.

Anatomical Variations of the Iliolumbar Vein With Application to the Anterior Retroperitoneal Approach to the Lumbar Spine: A Cadaver Study

Objectives of this study include identification of lumbosacral venous variations, designation of a critical area of dissection for surgical exposure, and comparison between both male/female and right/left‐sided anatomy. Attempts were made to provide anatomic nomenclature that accurately describes these structures. Thirty‐eight iliolumbar venous systems in 20 cadavers (11 females/9 males) were dissected. Each system was identified as one of three patterns of variation: common venous trunk (combining ascending lumbar and iliolumbar venous systems) with distal veins, common venous trunk without distal veins, and venous systems without a common venous trunk. Dimensions including distances to the inferior vena cava (IVC) confluence, the obturator nerve, and the lumbosacral trunk, and venous stem length were obtained to aid surgical dissection. Differences between males and females and those between right and left sides were compared. Anterior lumbosacral venous variations could be organized into three groups. A Type 1 venous system (common venous trunk with distal veins) was most common (53% of systems). The anatomical name “lateral lumbosacral veins” adequately describes the anatomical location of these veins and does not assume a direction of venous flow or the lack of individual distal veins. A critical area bordered by the obturator nerve anteriorly, the psoas muscle laterally, the spinal column medially, and sacrum posteriorly within 8.2 cm of the IVC confluence should be defined to adequately dissect the lateral lumbosacral veins. Differences in male and female lateral lumbosacral venous anatomy do not alter surgeons approach to the anterior lumbar spine. Clin. Anat. 21:666–673, 2008.

The Relationship of Throwing Arm Mechanics and Elbow Varus Torque: Within-Subject Variation for Professional Baseball Pitchers Across 82,000 Throws:

Background: Likely due to the high level of strain exerted across the elbow during the throwing motion, elbow injuries are on the rise in baseball. To identify at-risk athletes and guide postinjury return-to-throw programs, a better understanding of the variables that influence elbow varus torque is desired. Purpose: To describe the within-subject relationship between elbow varus torque and arm slot and arm rotation in professional baseball pitchers. Study Design: Descriptive laboratory study. Methods: A total of 81 professional pitchers performed 82,000 throws while wearing a motusBASEBALL sensor and sleeve. These throws represented a combination of throw types, such as warm-up/catch, structured long-toss, bullpen throwing from a mound, and live game activity. Variables recorded for each throw included arm slot (angle of the forearm relative to the ground at ball release), arm speed (maximal rotational velocity of the forearm), arm rotation (maximal external rotation of the throwing arm relative to the ground), and elbow varus torque. Linear mixed-effects models and likelihood ratio tests were used to estimate the relationship between elbow varus torque and arm slot, arm speed, and arm rotation within individual pitchers. Results: All 3 metrics—arm slot (χ2 = 428, P < .001), arm speed (χ2 = 57,683, P < .001), and arm rotation (χ2 = 1392, P < .001)—were found to have a significant relationship with elbow varus torque. Within individual athletes, a 1-N.m increase in elbow varus torque was associated with a 13° decrease in arm slot, a 116 deg/s increase in arm speed, and an 8° increase in arm rotation. Conclusion: Elbow varus torque increased significantly as pitchers increased their arm rotation during the arm cocking phase, increased the rotational velocity of their arm during the arm acceleration phase of throwing, and decreased arm slot at ball release. Thus, shoulder flexibility, arm speed, and elbow varus torque (and likely injury risk) are interrelated and should be considered collectively when treating pitchers. Clinical Relevance: It is well established that elbow varus torque is related to ulnar collateral ligament injuries in overhead throwers. This study describes the relationship of arm slot, arm speed, and arm rotation to elbow varus torque in an attempt to identify modifiable risk factors for injury.