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Recently, 3-dimensional (3D) printing technology has been used in the development of titanium metaphyseal cones to manage severe bone loss in revision total knee arthroplasty (rTKA). This study assessed (1) radiographs; (2) functional outcomes; (3) complications; and (4) 2-year implant survivorship in patients receiving 3D-printed titanium metaphyseal cones for moderate-to-severe tibial and femoral bone loss in rTKA. A single institution, retrospective chart review was performed for patients with large bone defects treated with a 3D-printed femoral or tibial titanium metaphyseal cone between 2015 and 2017 during rTKA (N=54). Paired sample t tests analyzed Knee Society Scores (KSS). Kaplan–Meier analyses determined implant survivorship when the endpoint was cone revision for aseptic loosening, cone revision for any reason, and reoperation for any reason. The authors found that 51 (98.1%) of 52 available radiographs demonstrated well-fixed components without any evidence of loosening or migration. Mean postoperative KSS scores were significantly higher when compared with preoperative scores (80.4 vs 52.0; P >.001). One patient experienced aseptic loosening of their cone. Seven additional cones were explanted as a consequence of reinfection, 1 of which was removed prior to arthrodesis. Cone survivorship was 98.5% when the endpoint was cone revision due to aseptic loosening, 88.2% when cone revision was due to any reason, and 77.9% for any reoperation. Metaphyseal cones appear to be well-suited for large bone defects during rTKA and the authors' findings suggest that cones may be a viable option for metaphyseal fixation during rTKA. Future studies should focus on their durability during a longer time period. [ Orthopedics . 2021;44(1):43–47.]

Background: Core muscle injury (CMI), often referred to as a sports hernia, is a common cause of groin pain in athletes characterized by concomitant injury to the insertion of the adductor longus and the rectus abdominis muscles. Currently, the literature on CMI is sparse with no standardized physical examination tests used in the diagnosis of this type of injury. Purpose: To determine the diagnostic accuracy of various physical examination tests in the diagnosis of CMI. Study Design: Cohort study (Diagnosis); Level of evidence, 3. Methods: A consecutive series of patients evaluated by the senior author with symptoms consistent with CMI were included. Four physical examination tests were routinely performed in these patients by the senior author and were noted in each patient’s chart as positive or negative: (1) pain with resisted cross-body sit-up in figure-of-4 position, (2) pain with straight-leg sit-up, (3) pain with resisted hip flexion in external rotation (external rotation Stinchfield test), and (4) the presence of an adductor contracture. CMI was independently diagnosed by a reference standard (magnetic resonance imaging [MRI]). All MRI scans were read by a musculoskeletal fellowship-trained radiologist. The sensitivity and specificity of each physical examination test alone and in combination were calculated based on this reference standard. Results: A total of 81 patients were included in this study. MRI was positive for a CMI in 39 patients (48%) overall. Both the cross-body sit-up test and the presence of an adductor contracture were found to have a sensitivity of 100% (specificity, 3% for both). The external rotation Stinchfield test was found to have the highest specificity of 60% (sensitivity, 15%). The sensitivity of all 4 physical examination tests in combination was found to be 100% (specificity, 0%). Conclusion: Certain physical examination maneuvers can be used to assist in the diagnosis of a CMI. The cross-body sit-up test and the presence of an adductor contracture are highly sensitive but nonspecific tests for CMI and therefore should be used in conjunction with diagnostic imaging before deciding on an appropriate treatment course.

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Background: Previous studies have demonstrated various groin-related nerve and soft tissue complications in patients undergoing hip arthroscopy with a perineal post. Purpose: To prospectively compare groin-related nerve and soft tissue complications between patients undergoing hip arthroscopy with and without the use of a perineal post. Study Design: Cohort study; Level of evidence, 2. Methods: A prospective single-surgeon cohort study was performed on all patients undergoing hip arthroscopy by the senior author between January 2020 and March 2022. A post-free hip distraction system was used at 1 center in which the senior author operates, and a system with a large padded perineal post was used at another surgical location. Patients completed a survey at the first postoperative visit (7-10 days) to determine if they had experienced any groin-related complications after surgery (groin numbness, sexual/urinary dysfunction, skin tears). Patients with a positive survey response repeated the survey at each follow-up visit (6 weeks, 3 months, 6 months) until the symptoms resolved. The rate and duration of groin-related complications were then compared between the groups. Results: A total of 87 patients were included in the study who underwent hip arthroscopy: 53 with a perineal post and 34 without. No differences were found between the post and postless groups in terms of age at surgery, sex, body mass index, or traction time. We found that 16 patients (30%) in the perineal post group experienced groin numbness versus 0 (0%) in the postless group ( P < .0001). On average, groin numbness lasted 5 ± 3 days (mean ± SD) in the perineal post group. Three patients in the perineal post group experienced sexual dysfunction for a mean 7 days, as compared with none in the postless group. Seventeen patients (32%) in the perineal post group experienced foot numbness versus 4 (12%) in the postless group ( P = .04). One patient in the perineal post group reported a superficial skin tear. Conclusion: Postless hip arthroscopy resulted in no risk of groin-related complications as compared with traditional hip arthroscopy with a perineal post.