Effects of Leg Length, Sex, Laterality, and the Intermediate Femoral Cutaneous Nerve on Infrapatellar Innervation.

Background: An iatrogenic injury to the infrapatellar branch of the saphenous nerve (IPBSN) is a common precipitant of postoperative knee pain and hypoesthesia. Purpose: To locate potential safe zones for incision by observing the patterns and pathway of the IPBSN while examining the relationship of its location to sex, laterality, and leg length. Study Design: Descriptive laboratory study. Methods: A total of 107 extended knees from 55 formalin-embalmed cadaveric specimens were dissected. The nerve was measured from palpable landmarks: the patella at the medial (point A) and lateral (point B) borders of the patellar ligament, the medial border of the patellar ligament at the patellar apex (point C) and tibial plateau (point D), the medial epicondyle (point E), and the anterior border of the medial collateral ligament at the tibial plateau (point F). The safe zone was defined as 2 SDs from the mean. Results: Findings indicated significant correlations between leg length and height (r P = 0.832; P < .001) as well as between leg length and vertical measurements (≥45°) from points A and B to the IPBSN (r P range, 0.193-0.285; P range, .004-.049). Male specimens had a more inferior maximum distance from point A to the intersection of the IPBSN and the medial border of the patellar ligament compared with female specimens (6.17 vs 5.28 cm, respectively; P = .049). Right knees had a more posterior IPBSN from point F compared with left knees (-0.98 vs-0.02 cm, respectively; P = .048). The majority of knees (62.6%; n = 67) had a nerve emerging that penetrated the sartorius muscle. Additionally, 32.7% (n = 35) had redundant innervation, and 25.2% (n = 27) had contribution from the intermediate femoral cutaneous nerve (IFCN). Conclusion: We identified no safe zone. Significant innervation redundancy with a substantial contribution to the infrapatellar area from the IFCN was noted and contributed to the expansion of the danger zone. Clinical Relevance: The location of incision and placement of arthroscopic ports might not be as crucial in postoperative pain management as an appreciation of the variance in infrapatellar innervation. The IFCN is a common contributor. Its damage could explain pain refractory to SN blocks and therefore influence anesthetic and analgesic decisions.

Side Variations of Anterior Cruciate Ligament Coronal Angles: Implications for ACL Reconstruction.

Current literature has shown a biomechanical advantage of recreating the native coronal obliquity of the anterior cruciate ligament (ACL) during grating procedures; however, the majority of studies on ACL morphological variation have been performed unilaterally. This cadaveric study aimed to evaluate sided ACL coronal angle of inclination variation including trend analysis with sex, age, height, and femoral condyle width. The ACLs of 57 embalmed cadaveric specimens were evaluated bilaterally for a total of 114 ACLs. The knees were flexed to 110°. A 0.70-mm wire measured coronal angulation through the lateral tibial plateau and the medial ACL border. An image taken of the wire allowed digital measurement with the ImageJ software. IBM SPSS was utilized for statistical analysis. Bilateral measurements demonstrated a difference in an individual's sided ACL angulation (P < 0.001). Right-sided angulation was greater in 61.4% (35/57). In cadavers with greater right-side angulation, right ACLs averaged 66.2° versus left ACLs averaged 60.9° (P < 0.001). Cadavers with greater left-sided ACL angles demonstrated average left ACLs measuring 65.5° versus right ACLs measuring 60.6° (P < 0.001). Right-sided angles were greater in 69.7% of females. Understanding the anatomy of the ACL's native coronal angle and variations between a patient's knees is imperative during reconstruction surgery to aid in anatomic tunnel placement for improved knee motion and rotational knee kinematics following surgery. A statistically significant difference exists between an individual's right and left ACL coronal angles of inclination. Clin. Anat. 32:1102-1106, 2019. © 2019 Wiley Periodicals, Inc.

Enhancement of anatomical learning and developing clinical competence of first-year medical and allied health profession students.

Hands-on educational experiences can stimulate student interest, increase knowledge retention, and enhance development of clinical skills. The Lachman test, used to assess the integrity of the anterior cruciate ligament (ACL), is commonly performed by health care professionals and is relatively easy to teach to first-year health profession students. This study integrated teaching the Lachman test into a first-year anatomy laboratory and examined if students receiving the training would be more confident, competent, and if the training would enhance anatomical learning. First-year medical, physician assistant and physical therapy students were randomly assigned into either the intervention (Group A) or control group (Group B). Both groups received the course lecture on knee anatomy and training on how to perform the Lachman test during a surface anatomy class. Group A received an additional 15 minutes hands-on training for the Lachman test utilizing a lightly embalmed cadaver as a simulated patient. One week later, both groups performed the Lachman test on a lightly embalmed cadaver and later completed a post-test and survey. Students with hands-on training performed significantly better than students with lecture-only training in completing the checklist, a post-test, and correctly diagnosing an ACL tear. Students in Group A also reported being more confident after hands-on training compared to students receiving lecture-only training. Both groups reported that incorporating clinical skill activities facilitated learning and created excitement for learning. Hands-on training using lightly embalmed cadavers as patient simulators increased confidence and competence in performing the Lachman test and aided in learning anatomy.