Changes in knee mechanics following anterior cruciate ligament reconstruction (ACLR) have been implicated as a contributor to the development of premature osteoarthritis (OA). However, changes in ambulatory loading in this population have not been well documented. While the magnitude of the external knee moment vector is a major factor in loading at the knee, there is not a comprehensive understanding of the changes in the individual components of the vector following ACL reconstruction. The purpose of this study was to test for differences in the three components of the external knee moment during walking and stair locomotion between ACLR, contralateral and healthy control knees. Forty-five ACLR and 45 healthy control subjects were tested during walking, stair ascent and descent. ACLR knees had a lower first peak adduction moment than contralateral knees during all three activities. Similarly, additional cases of significant differences between ACLR and contralateral knees consisted of lower peak moments for the ACLR than the contralateral knees. These differences were due to both ACLR and contralateral knees as the ACLR knees indicated lower and the contralateral knees greater peak moments compared to healthy control knees. The results suggest a compensatory change involving greater loading in the contralateral knee, perhaps due to lower loading of the ACLR knee. Further, lower knee moments of the ACLR knee suggest that increased joint loading may not be the initiating factor in the development of OA following ACL reconstruction; but rather previous described kinematic or biological changes might initiate the pathway to knee OA.

The postoperative DTH responses of the open surgery patients were significantly smaller than their preoperative responses. This was not the case for the laparoscopic group (a combination of fully laparoscopic and laparoscopic-assisted resections). When the open and laparoscopic groups results are directly compared, regarding the results of the day of surgery DTH challenges, the LC groups median percent change from baseline was significantly less than that observed in the OC group. These results imply that open colorectal resection is associated with a significant suppression of cell-mediated immune response postoperatively, whereas in this study laparoscopic colorectal resection was not. Further human studies are needed to verify these findings and to determine the clinical significance, if any, of this temporary difference in immune function following colon resection.

Recent reports have indicated that anatomical placement of the anterior cruciate ligament (ACL) graft is an important factor for restoration of joint function following ACL reconstruction. The objective of this study was to address a need for a better understanding of anatomical variations in ACL position and orientation within the joint. Specifically, variations in the ACL anatomy were assessed by testing for side-to-side ACL footprint location symmetry in a healthy population relative to the operative and contralateral knee in a patient population after traditional transtibial single-bundle ACL reconstruction. MRI and three-dimensional modeling techniques were used to determine the in vivo tibiofemoral ACL footprint centers and the resulting ACL orientations in both knees of 30 healthy subjects and 30 subjects after transtibial ACL reconstruction. While there were substantial inter-subject variations in ACL anatomy, the side-to-side RMS differences in the ACL footprint center were 1.20 and 1.34 mm for the femur and tibia, respectively, for the healthy subjects and no clinically meaningful intra-subject differences were measured. However, there were large intrasubject side-to-side differences after transtibial ACL reconstruction, with ACL grafts placed 5.63 and 7.64 mm from the center of the contralateral femoral and tibial ACL footprint centers, respectively. Grafts were placed more medial, anterior, and superior on the femur and more posterior on the tibia; producing grafts that were more vertical in the sagittal and coronal planes. Given the large variation among subjects, these findings advocate the use of the contralateral ACL morphology for retrospectively evaluating patientspecific anatomic graft placement. ß

Background: Meniscal repair leads to improved patient outcomes compared with meniscectomy in small case series. Purpose: To compare the reoperation rates, 30-day complication rates, and cost differences between meniscectomy and meniscal repair in a large insurance database. Study Design: Cohort study; Level of evidence, 3. Methods: A national insurance database was queried for patients who underwent meniscectomy (Current Procedural Terminology [CPT] code 29880 or 29881) or meniscal repair (CPT code 29882 or 29883) in the outpatient setting and who had a minimum 2-year follow-up. Patients without confirmed laterality and patients who underwent concomitant ligament reconstruction were excluded. Reoperation was defined by ipsilateral knee procedure after the index surgery. The 30-day postoperative complication rates were assessed using the International Classification of Diseases, 9th Revision, Clinical Modification codes. The cost of the procedures per patient was calculated. Propensity score matching was utilized to create matched cohorts with similar characteristics. Statistical comparisons of cohort characteristics, reoperations, postoperative complications, and payments were made. All P values were reported with significance set at P < .05. Results: A total of 27,580 patients (22,064 meniscectomy and 5516 meniscal repair; mean age, 29.9 ± 15.1 years; 41.2% female) were included in this study with a mean follow-up of 45.6 ± 21.0 months. The matched groups were similar with regard to characteristics and comorbidities. There were significantly more patients who required reoperation after index meniscectomy compared with meniscal repair postoperatively (5.3% vs 2.1%; P < .001). Patients undergoing meniscectomy were also significantly more likely to undergo any ipsilateral meniscal surgery ( P < .001), meniscal transplantation ( P = .005), or total knee arthroplasty ( P = .001) postoperatively. There was a significantly higher overall 30-day complication rate after meniscal repair (1.2%) compared with meniscectomy (0.82%; P = .011). The total day-of-surgery payments was significantly higher in the repair group compared with the meniscectomy group ($7094 vs $5423; P < .001). Conclusion: Meniscal repair leads to significantly lower rates of reoperation and higher rates of early complications with a higher total cost compared with meniscectomy in a large database study.

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Basic science biomechanical study.

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It was not possible with this model to aerosolize tumor cells in a pressurized CO2 environment. Our results suggest that aerosolization of tumor cells is not the mechanism of port site recurrences after laparoscopic surgery for malignant disease.