The medial epicondyle of the distal femur is the optimal location for MRI measurement of semitendinosus and gracilis tendon cross-sectional area.

PURPOSE: Graft diameter ≥ 8 mm reduces the risk of failure after anterior cruciate ligament reconstruction (ALCR) with hamstring tendon autograft. Pre-operative measurement of gracilis (GT) and semitendinosus (ST) cross-sectional area using MRI has been utilized but the optimal location for measurement is unknown. The main purpose of this study was to examine the cross-sectional areas of GT + ST at different locations and develop a model to predict whether a doubled hamstring graft of GT + ST will be of sufficient cross-sectional area for ACLR. METHODS: A retrospective review was performed of 154 patients who underwent primary ACLR using doubled hamstring autograft. Cross-sectional area measurements of GT + ST on pre-operative MRI axial images were made at three locations: medial epicondyle (ME), tibiofemoral joint line (TJL), and tibial physeal scar (TPS) and calculated the correlation of intra-operative graft size for each location using the Pearson's correlation coefficient. A receiver operating characteristic (ROC) established a threshold that would predict graft diameter ≥ 8 mm. RESULTS: Measurement of GT + ST at the ME had a stronger correlation (r = 0.389) to intra-operative graft diameter than measurements at the TJL (r = 0.256) or TPS (r = 0.240). The ROC indicated good predictive value for hamstring graft diameter ≥ 8 mm based on MRI measurement at the ME with the optimal threshold with the highest sensitivity and specificity as 18 mm2. CONCLUSION: Cross-sectional area measurement of GT + ST at the ME correlated most closely to intra-operative diameter of a doubled hamstring autograft compared to measurements at the TJL or the TPS. As graft diameter < 8 mm is correlated with higher failure rates of ACL surgery, the ability to pre-operatively predict graft diameter is clinically useful. LEVEL OF EVIDENCE: Level III, prognostic study.

A comparison of outcomes between open and laparoscopic surgical repair of recurrent inguinal hernias.

BACKGROUND: Inguinal hernia recurrence after surgical repair is a major concern. The authors report their experience with open and laparoscopic repair of recurrent inguinal hernias. METHODS: After institutional review board approval, a retrospective review was performed with the charts of 197 patients who had undergone surgical repair of recurrent inguinal hernias from January 2000 through August 2009, and the data for 172 patients who met the inclusion criteria were analyzed. Surgical variables and clinical outcomes were compared using Student's t test, the Mann-Whitney U test, chi-square, and Fisher's exact test as appropriate. RESULTS: The review showed that 172 patients had undergone either open mesh repair (n=61) or laparoscopic mesh repair (n=111) for recurrent inguinal hernias. Postoperative complications were experienced by 8 patients in the open group and 17 patients in laparoscopic group (p=0.70). Five patients (8.2%) in the open group and four patients (3.6%) in the laparoscopic group had re-recurrent inguinal hernias (p=0.28). Four patients in the open group (9.5%) and no patients in the laparoscopic group had recurrence during long-term follow-up evaluation (p=0.046). In the laparoscopic group, 76 patients (68.5%) underwent total extraperitoneal (TEP) repair, and 35 patients (31.5%) had transabdominal preperitoneal (TAPP) repair. Postoperative complications were experienced by 13 patients in the TEP group and 4 patients in the TAPP group (p=0.44). Two patients (2.6%) in the TEP group and two patients (5.7%) in the TAPP group had re-recurrent inguinal hernias (p=0.59). CONCLUSIONS: This retrospective review showed no statistical difference in the re-recurrence rate between the two techniques during short-term follow-up evaluation. However, the laparoscopic technique had a significantly lower re-recurrence rate than the open technique during long-term follow-up evaluation. Both procedures were comparable in terms of intra- and postoperative complications. Among laparoscopic techniques, TEP and TAPP repair are acceptable methods for the repair of recurrent inguinal hernia. A multicenter prospective randomized control trial is needed to confirm the findings of this study.

Pollinator flight directionality and the assessment of pollen returns.

Nectar-foraging pollinators often exhibit a directional pattern of movement between plants when the energetic costs of revisiting previously utilized areas can significantly reduce foraging efficiency. However, bumblebees (Bombus spp.) foraging for pollen on flowers of Aquilegia caerulea rarely moved in a straight line among successively visited plants. Most flights from plants visited were either to closely neighboring plants or were longer and involved bypassing near neighbor plants. Bees biased their flights toward plants with relatively large numbers of flowers yet visited only a small fraction of the flowers on each plant. Such foraging tactics might result when the energetic costs of revisiting plants are minor. Alternatively we suggest that bumblebees foraging for pollen may not perceive revisitations and their associated costs because they do not assess pollen returns on a per plant basis. In this case energetic-efficiency arguments predicting the pattern of foraging movements among plants may be inappropriate. A better level of analysis would be where the bees assess net energy returns, perhaps between bouts of pollen-combing and corbiculae-packing.