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High tibial osteotomy is becoming increasingly popular but can be associated with unintentional posterior tibial slope (PTS) increase and subsequent anterior cruciate ligament (ACL) degeneration. This study quantified the effect of increasing PTS on knee kinematics and in situ forces in the native ACL. A robotic testing system was used to apply external loads from full extension to 90° flexion to seven human cadaveric knees: (1) 200 N axial compressive load, (2) 5 Nm internal tibial + 10 Nm valgus torque, and (3) 5 Nm external tibial + 10 Nm varus torque. Kinematics and in situ forces in the ACL were acquired for the native and increased PTS state. Increasing PTS resulted in increased anterior tibial translation at 30° (1.8 mm), 60° (1.7 mm), and 90° (0.9 mm) flexion and reduced in situ force in the ACL at 30° (57.6%), 60° (69.8%), and 90° (75.0%) flexion in response to 200 N axial compressive load. In response to 5 Nm internal tibial + 10 Nm valgus torque, there was significantly less (39.0%) in situ force in the ACL at 90° flexion in the increased compared with the native PTS state. Significantly less in situ force in the ACL at 60° (62.8%) and 90° (67.0%) flexion was observed in the increased compared with the native PTS state in response to 5 Nm external tibial + 10 Nm varus torque. Increasing PTS affects knee kinematics and results in a reduction of in situ forces in the native ACL during compressive and rotatory loads at flexion angles exceeding 30°. In a controlled laboratory setting PTS increase unloads the ACL, affecting its natural function. [ABSTRACT FROM AUTHOR]

Background: Recent evidence questions the role of medial opening wedge high tibial osteotomy (mowHTO) in the correction of femoral-based varus malalignment because of the potential creation of an oblique knee joint line. However, the clinical effectiveness of alternatively performing an isolated lateral closing wedge distal femoral osteotomy (lcwDFO), in which the mechanical unloading effect in knee flexion may be limited, is yet to be confirmed. Purpose/Hypothesis: The purpose of this article was to compare clinical outcomes between patients undergoing varus correction via isolated lcwDFO or mowHTO, performed according to the location of the deformity, in a cohort matched for confounding variables. It was hypothesized that results from undergoing isolated lcwDFO for symptomatic varus malalignment would not significantly differ from the results after mowHTO. Study Design: Cohort study; Level of evidence, 3. Methods: Consecutive patients who underwent isolated mowHTO or lcwDFO according to a tibial- or femoral-based symptomatic varus deformity between January 2010 and October 2019 were enrolled. Confounding factors, including age at surgery, sex, body mass index, preoperative femorotibial axis, and postoperative follow-up, were matched using propensity score matching. The International Knee Documentation Committee (IKDC) Subjective Knee Form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Tegner Activity Scale, and visual analog scale (VAS) for pain were collected preoperatively and at a minimum of 24 months postoperatively. Results: Of 535 knees assessed for eligibility, 50 knees (n = 50 patients, n = 25 per group) were selected by propensity score matching. Compared with preoperatively, both the mowHTO group (IKDC, 55.1 ± 16.5 vs 71.3 ± 14.7, P =.002; WOMAC, 22.0 ± 18.0 vs 9.6 ± 10.8, P <.001; Lysholm, 55.2 ± 23.1 vs 80.7 ± 16, P <.001; VAS, 4.1 ± 2.4 vs 1.6 ± 1.8, P <.001) and the lcwDFO group (IKDC, 49.4 ± 14.6 vs 66 ± 20.1, P =.003; WOMAC, 25.2 ± 17.0 vs 12.9 ± 17.6, P =.003; Lysholm, 46.5 ± 15.6 vs 65.4 ± 28.7, P =.011; VAS, 4.5 ± 2.2 vs 2.6 ± 2.5, P =.001) had significantly improved at follow-up (80 ± 20 vs 81 ± 43 months). There were no significant differences between the groups at baseline, at final follow-up, or in the amount of clinical improvement in any of the outcome parameters (P >.05; respectively). Conclusion: Performing both mowHTO or lcwDFO yields significant improvement in clinical outcomes if performed at the location of the deformity of varus malalignment. These findings confirm the clinical effectiveness of performing an isolated lcwDFO in femoral-based varus malalignment, which is comparable with that of mowHTO in the correction of varus malalignment. [ABSTRACT FROM AUTHOR]

Background: A posterior tibial slope (PTS) >12° has been shown to correlate with failure of anterior cruciate ligament (ACL) reconstruction (ACLR). PTS-reducing osteotomy has been described to correct the PTS in patients with a deficient ACL, mostly after failure of primary ACLR. Purpose: To report radiologic indices, clinical outcomes, and postoperative complications after PTS-reducing osteotomy performed concurrently with revision ACLR (R-ACLR). Study Design: Case series; Level of evidence, 4. Methods: A review of medical records at 3 institutions was performed of patients who had undergone PTS-reducing osteotomy concurrently with R-ACLR between August 2010 and October 2020. Radiologic parameters recorded included the PTS, patellar height according to the Caton-Deschamps Index (CDI), and anterior tibial translation (ATT). Patient-reported outcomes (International Knee Documentation Committee [IKDC] and Knee injury and Osteoarthritis Outcome Score [KOOS]), reoperations, and complications were evaluated. Results: Included were 23 patients with a mean follow-up of 26.7 months (range, 6-84 months; median, 22.5 months). Statistically significant differences from preoperative to postoperative values were found in PTS (median [range], 14.0° [12°-18°] vs 4.0° [0°-15°], respectively; P <.001), CDI (median, 1.00 vs 1.10, respectively; P =.04) and ATT (median, 8.5 vs 3.6 mm, respectively; P =.001). At the final follow-up, the IKDC score was 52.4 ± 19.2 and the KOOS subscale scores were 81.5 ± 9.5 (Pain), 74 ± 21.6 (Symptoms), 88.5 ± 8 (Activities of Daily Living); 52.5 ± 21.6 (Sport and Recreation), and 48.8 ± 15.8 (Quality of Life). A traumatic ACL graft failure occurred in 2 patients (8.7%). Reoperations were necessary for 6 patients (26.1%) because of symptomatic hardware, and atraumatic recurrent knee instability was diagnosed in 1 patient (4.3%). Conclusion: Tibial slope–reducing osteotomy resulted in a significant decrease of ATT and can be considered in patients with a preoperative PTS ≥12° and ≥1 ACLR failure. In highly complex patients with multiple prior surgeries, the authors found a reasonably low graft failure rate (8.7%) when utilizing PTS-reducing osteotomy. Surgeons must be aware of potential complications in patients with multiple previous failed ACLRs. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the incidence, morphology, and associated complications of medial cortical hinge fractures after lateral closing wedge distal femoral osteotomy (LCW-DFO) for varus malalignment and to identify constitutional and technical factors predisposing for hinge fracture and consecutive complications.Methods: Seventy-nine consecutive patients with a mean age of 47 ± 12 years who underwent LCW-DFO for symptomatic varus malalignment at the authors' institution between 01/2007 and 03/2018 with a minimum of 2-year postoperative time interval were enrolled in this retrospective observational study. Demographic and surgical data were collected. Measurements evaluating the osteotomy cut (length, wedge height, hinge angle) and the location of the hinge (craniocaudal and mediolateral orientation, relation to the adductor tubercle) were conducted on postoperative anterior-posterior knee radiographs and the incidence and morphology of medial cortical hinge fractures was assessed. A risk factor analysis of constitutional and technical factors predisposing for the incidence of a medial cortical hinge fracture and consecutive complications was conducted.Results: The incidence of medial cortical hinge fractures was 48%. The most frequent morphological type was an extension fracture type (68%), followed by a proximal (21%) and distal fracture type (11%). An increased length of the osteotomy in mm (53.1 ± 10.9 vs. 57.7 ± 9.6; p = 0.049), an increased height of the excised wedge in mm (6.5 ± 1.9 vs. 7.9 ± 3; p = 0.040) as well as a hinge location in the medial sector of an established sector grid (p = 0.049) were shown to significantly predispose for the incidence of a medial cortical hinge fracture. The incidence of malunion after hinge fracture (14%) was significantly increased after mediolateral dislocation of the medial cortical bone > 2 mm (p < 0.05).Conclusion: Medial cortical hinge fractures after LCW-DFO are a common finding. An increased risk of sustaining a hinge fracture has to be expected with increasing osteotomy wedge height and a hinge position close to the medial cortex. Furthermore, dislocation of a medial hinge fracture > 2 mm was associated with malunion and should, therefore, be avoided.Level Of Evidence: Prognostic study; Level IV. [ABSTRACT FROM AUTHOR]

Purpose: To evaluate the incidence and morphology of medial cortical hinge fractures in lateral open wedge distal femoral osteotomy (LOW-DFO) and to determine a safe zone for the position of the osteotomy hinge to minimize the risk of hinge fractures.Methods: Consecutive patients who underwent LOW-DFO for symptomatic valgus malalignment were screened for eligibility for this retrospective observational cohort study. Demographical and surgical data were collected. The incidence and morphology of medial cortical hinge fractures were evaluated on standard postoperative anterior-posterior knee radiographs. Comprehensive measurements evaluating the osteotomy gap and the position of the osteotomy hinge were taken. Additionally, each osteotomy hinge was assigned to a corresponding sector of a proposed five-sector grid of the distal medial femur.Results: A total of 100 patients (60% female) with a mean age of 31 ± 13 years were included. The overall incidence of medial cortical hinge fractures was 46% and three distinct fracture types were identified. The most frequently observed fracture type was extension of the osteotomy gap (76%), followed by a proximal (20%) and distal (4%) course of the fracture line in relation to the hinge. Group comparison (hinge fracture vs. no hinge fracture) showed statistically significant higher values for the height of the osteotomy gap (p = 0.001), the wedge angle (p = 0.036), and the vertical distance between the hinge and the proximal margin of the adductor tubercle (AT; p = 0.002) in the hinge fracture group. Furthermore, a significantly lower horizontal distance between the hinge and the medial cortical bone (p = 0.036) was observed in the hinge fracture group. A statistically significant higher incidence of medial cortical hinge fractures was observed when the position of the osteotomy hinge was proximal compared to distal to the proximal margin of the AT (53% vs. 27%; p = 0.023).Conclusion: Medial cortical hinge fractures in LOW-DFO are a common finding with three distinct fracture types. To minimize the risk of medial cortical hinge fractures, it is recommended to aim for a position of the osteotomy hinge at the level of or distal to the proximal margin of the adductor tubercle.Level Of Evidence: Prognostic study; Level III. [ABSTRACT FROM AUTHOR]

Purpose: To analyze postoperative physical and sexual activity as well as Quality of Life (QoL) after complex patellofemoral reconstructions in female patients suffering from chronic patellofemoral instability (PFI). Methods: Female patients aged > 18 years undergoing complex patellofemoral reconstruction for chronic PFI were included. Complex patellofemoral reconstruction was defined as medial patellofemoral ligament reconstruction (MPFL-R) combined with at least one major bony procedure (distal femoral osteotomy, high tibial osteotomy, and trochleoplasty). Outcome was evaluated retrospectively after a minimum follow-up of 12 months using Tegner activity scale, Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0), EuroQol-5D-3L (EQ-5D-3L), EuroQol Visual analog scale (EQ-VAS), and a questionnaire about sexual activity. Results: A total of 34 females (mean age, 26 ± 5 years) with a mean follow-up of 45 ± 16 months were included. Seventy-seven percent had one major bony correction + MPFL-R and 24% had at least two major bony corrections + MPFL-R. The re-dislocation rate was 6%. Median Tegner activity scale improved from 3 (range 0–10) to 4 (range 2–6) (n.s.) and an improved activity level was observed in 49% of subjects. QoL scores showed an EQ-5D-3L Index Value of 0.89 ± 0.15, EQ-VAS of 80.3 ± 11.4, and BPII of 68.3 ± 19.1. Thirty-four percent of patients reported restrictions of sexual activities due to PFI preoperatively with an improved sexual function observed in 60% postoperatively due to less pain, improved mobility, and less apprehension. Postoperative return to sexual activity was 91%, whereof 19% reported current restrictions of sexual function because of pain and/or limited range of motion. Conclusion: Despite the complexity and invasiveness of complex patellofemoral reconstruction, combined bony procedures and MPFL-R resulted in a low redislocation rate, improved physical activity and QoL comparable to values reported after isolated MPFL-R. Furthermore, sexual activity was improved in 60% of females with preoperative restrictions. Level of evidence: IV. [ABSTRACT FROM AUTHOR]

Purpose: To perform a segmental analysis of tibial torsion in patients, with normal and increased external tibial torsion, suffering from chronic patellofemoral instability (PFI) and to investigate a possible correlation between tibial torsion and the position of the tibial tuberosity. Methods: Patients with chronic PFI who underwent torsional analysis of the lower limb using a standardized hip-knee-ankle MRI between 2016 and 2018 were included. For segmental analysis of tibial torsion, three axial levels were defined which divided the tibia into two segments: a distal, infratuberositary segment and a proximal, supratuberositary segment. Torsion was measured for the entire tibia (total tibial torsion, TTT), the proximal segment (proximal tibial torsion, PTT), and the distal segment (distal tibial torsion, DTT). Based on TTT, patients were assigned to one of two groups: Normal TTT (< 35°) or increased external TTT (> 35°). Position of the tibial tuberosity was assessed on conventional MRI scans by measuring the tibial tuberosity-trochlea groove (TT-TG) and the tibial tuberosity-posterior cruciate ligament (TT-PCL) distances. Results: Ninety-one patients (24 ± 6 years; 78% female) were included. Mean external TTT was 29.6° ± 9.1° and 24 patients (26%) had increased external TTT. Compared to patients with normal TTT, patients with increased external TTT demonstrated significantly higher values for DTT (38° ± 8° vs. 52° ± 9°; p < 0.001), whereas no difference was found for PTT (– 13° ± 6° vs. – 12° ± 6°; n.s.). Furthermore, a significant correlation was found between TTT and DTT (p < 0.001), whereas no correlation was found between TTT and PTT (n.s). With regard to TT-TG and TT-PCL distances, no significant differences were observed between the two groups (TT-TG: 15 ± 6 vs. 14 ± 4 mm, n.s.; TT-PCL: 22 ± 4 vs. 21 ± 5 mm, n.s.) and no correlation was found with TTT, DTT, or PTT (n.s.). Conclusion: In patients with chronic PFI, increased external TTT of greater than 35° is an infratuberositary deformity and does not correlate with a lateralized position of the tibial tuberosity. Level of evidence: Level III. [ABSTRACT FROM AUTHOR]