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Background: The purpose of this study was to evaluate the ultimate failure load and stiffness of two patellar fixation techniques for medial patellofemoral ligament (MPFL) reconstruction: (1) quadriceps tendon fixation (QT), (2) single tunnel (STG) patella fixation with gracilis autograft., Methods: A total of 16 fresh-frozen cadaveric knees (eight matched pairs) were randomized into two groups (QT vs. STG). The MPFL reconstructions were subjected to cyclic loading for 10 cycles to 30 N and then tested to failure at a constant displacement rate of 15 mm/min using a materials-testing machine (MTS 810 Universal Testing System). Failure mode, ultimate failure load and stiffness were recorded for each cadaveric specimen., Results: There was no significant difference in mean ultimate failure load among groups (P = 0.35). The STG group failed at a mean ultimate load of 190.04 N [standard deviation (SD) 23.18] and the QT group failed at 206.24 N (SD 37.99). The STG group had a mean stiffness of 21.38 N/mm (SD 1.44). This was not significantly higher than the mean stiffness value achieved for the QT group at 20.36 N/mm (SD 1.3) (P = 0.19). In the QT group all reconstructions failed due to tendon rupture at the patella attachment. The reason for failure in the STG group was the graft-suture connection., Conclusions: This cadaver study showed no statistically significant difference in biomechanical performance of the evaluated patella fixation techniques, in terms of maximum load to failure and stiffness. Both techniques are reliable in terms of biomechanical properties and could offer additional surgical solutions., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

Purpose: The purpose of this study was to compare the maximum load to failure and stiffness of three medial patella-femoral ligament (MPFL) reconstruction techniques: (i) suture anchor fixation (SA), (ii) interference screw fixation (SF), and (iii) suture knot (SK) patellar fixation. The null hypothesis was that the comparison between these three different patella fixation techniques would show no difference in the ultimate failure load and stiffness., Methods: Reconstruction of the MPFL with gracilis tendon autograft was performed in 12 pairs of fresh-frozen cadaveric knees (24 knees total; mean age, 63.6 [Formula: see text] 8.0 years). The specimens were randomly distributed into 3 groups of 8 specimens; SA reconstruction was completed with two 3.0-mm metal suture anchors; (SF) fixation was accomplished by two 6-mm bio-composite interference screws; SK fixation at the lateral side of the patella was accomplished after drilling two semi-patellar tunnels with a diameter of 4.5 mm. The reconstructions were subjected to cyclic loading for 10 cycles to 30 N and tested to failure at a constant displacement rate of 15 mm/min using a materials-testing machine (MTS 810 Universal Testing System). The final load of failure (N), stiffness (N / mm) and failure mode was recorded in each specimen and followed by statistical analysis., Results: There was no significant difference in mean ultimate failure load among the three groups. The SK group failed at a mean ([Formula: see text] SD) ultimate load of 253.5 [Formula: see text] 38.2 N, the SA group failed at 243 [Formula: see text] 41.9 N and the SF group at 263.2 [Formula: see text] 9.06 N. The SF group had a mean stiffness of 37.8 [Formula: see text] 5.7 N/mm. This was significantly higher (p < 0.05) than the mean stiffness value achieved for the SK group 21.4 [Formula: see text] 9.5 N/mm and the SA group 18.7 [Formula: see text] 3.4 N/mm. The most common mode of failure in the SA group was anchor pullout, and in the SK group was failure at the graft-suture interface. All the reconstructions in the SF group failed due to tendon graft slippage from the tunnel., Conclusion: Load to failure was not significantly different between the 3 techniques. However, screw fixation was found to be significantly stronger than the anchor and the suture knot fixation in terms of rigidity of the reconstruction. From a clinical point of view, all methods of fixation can be used reliably for MPFL reconstruction, since they were found to be stronger than the native MPFL., (© 2021. European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

This research focuses on the anatomical insertion of the synovial capsule around the knee. The attachments of the capsule were measured in 50 knee MR imaging studies with large intraarticular effusion. Corresponding measurements were performed in 20 fresh frozen cadaveric specimens, for validation. Femoral and tibial capsular reflections were defined as the distances between the attachment sites of the capsule and the femoral or tibial joint line and they were recorded in three coronal planes (anterior/middle/posterior). On MR imaging, the lateral/medial femoral capsular reflection mean values were 6.5/4.57 cm, 2.74/1.74 cm and 1.52/1.99 cm in the anterior, middle and posterior plane, respectively. MR imaging-based measurements did not differ significantly compared to corresponding cadaveric measurements. The mean values of the lateral/medial tibial capsular reflection on MR imaging were 0.09/0.11 cm, 0.34/0.26 cm and 0.62/0.34 cm in the anterior, middle and posterior plane, respectively. On cadaveric dissection, the maximum mean value was 1.45 cm, measured on the lateral side of the anterior plane. Apart from the lateral aspect of the posterior plane, MR imaging measurements were significantly lower, compared to the corresponding cadaveric measurements. The greatest femoral and tibial capsular reflections were found on the anterior and lateral side of the anterior plane. MR imaging appears to underestimate the distal extent of the knee capsule. Anatomical details of the knee capsule should be considered for safe insertion of external fixator pins.

Purpose: To determine and compare the incidence of post-operative septic arthritis following revision anterior cruciate ligament reconstruction (R-ACLR) with autologous quadriceps tendon (with patellar bone block) compared to autologous hamstring tendons (semitendinosus and gracilis)., Methods: A total of 1638 isolated R-ACLR with either autologous hamstring tendons (n = 1004, 61.3%) or quadriceps tendon (n = 634; 38.7%) were performed between 2004 and 2017 and were retrospectively analysed with regard to the occurrence of post-operative septic arthritis. The technique of R-ACLR did not significantly change during the years of the study. All patients received pre-op i.v.antibiotics, but no presoaking of the grafts in vancomycin was performed in the years of the study. The individual decision of graft choice was based on graft availability, tunnel position and the presence of tunnel widening. Generally, hamstring tendons were preferred. There were no clinically relevant differences between the groups regarding gender or age. Routine follow-up examination was performed 6 weeks after the index operation (follow-up rate 96.5%), and patients unsuspicious for septic arthritis at that time were classified as non-infected., Results: Fourteen patients with septic arthritis were identified, resulting in an overall incidence of 0.85%. There was one patient with septic arthritis in the quadriceps tendon group (incidence: 0.16%) and 13 patients in the hamstring tendons group (incidence: 1.29%), respectively. The difference was significant (p = 0.013)., Conclusion: In this series, the incidence of post-operative septic arthritis after R-ACLR was lower when quadriceps tendon graft was used compared to hamstring tendon grafts., Level of Evidence: III.

Objective: The purpose of this study is to describe the MRI findings and treatment decisions and outcome for Morel-Lavallée lesions (MLLs) of the knee and to investigate whether evidence exists to support an increased frequency of such lesions on the medial or lateral side by performing a cadaveric experiment., Materials and Methods: In a 4-year period, 24 MRI studies of 24 consecutive patients (16 male patients and eight female patients) with knee MLLs were retrospectively reviewed. Patient demographic characteristics, treatment decisions and outcome, and associated injuries were recorded. The location of the MLL was categorized as medial, lateral, or global. Lesions were categorized according to an established MRI classification. During the cadaveric experiment, the compartmental pressures of the medial or lateral aspect of the knee were monitored in 20 cadaveric knees. The chi-square test, t test, and Pearson correlation were used for statistical analysis., Results: MLLs were located medially in 16 patients, laterally in two patients, and globally in six patients. The medial location was significantly more common than a lateral or global location (p < 0.05). MLLs were classified as type I in 14 patients, type II in eight patients, and type III in two patients. MRI type was correlated with the chronicity of injury (r 2 = 0.614; p = 0.0014). Fractures were the most common associated injuries, occurring in seven of 24 patients. In 17 patients, all of whom had conservatively treated type I or type II lesions, complete resolution of the MLL occurred. The maximum compartmental pressures were significantly higher on the lateral side than on the medial side (p < 0.0001)., Conclusion: Knee MLLs have a predilection for the medial side, which may be attributed to the lower resistance in this location, and they have variable patterns on MRI, which correlate with chronicity. Conservative treatment of type I and II lesions seems effective.

Background: When arthroscopic rotator cuff repair is performed on a young patient, long-lasting structural and functional tendon integrity is desired. A fixation technique that potentially provides superior tendon healing should be considered for the younger population to achieve long-term clinical success. Hypothesis/Purpose: The purpose was to compare the radiological and clinical midterm results between single-row and double-row (ie, suture bridge) fixation techniques for arthroscopic rotator cuff repair in patients younger than 55 years. We hypothesized that a double-row technique would lead to improved tendon healing, resulting in superior mid- to long-term clinical outcomes., Study Design: Cohort study; Level of evidence, 2., Methods: A consecutive series of 66 patients younger than 55 years with a medium to large full-thickness tear of supraspinatus and infraspinatus tendons who underwent arthroscopic single-row or double-row (ie, suture bridge) repair were enrolled and prospectively observed. Thirty-four and 32 patients were assigned to single-row and double-row groups, respectively. Postoperatively, tendon integrity was assessed by MRI following Sugaya's classification at a minimum of 12 months, and clinical outcomes were assessed with the Constant score and the University of California, Los Angeles (UCLA) score at a minimum of 2 years., Results: Mean follow-up time was 46 months (range, 28-50 months). A higher tendon healing rate was obtained in the double-row group compared with the single-row group (84% and 61%, respectively [ P < .05]). Although no difference in outcome scores was observed between the 2 techniques, patients with healed tendon demonstrated superior clinical outcomes compared with patients who had retorn tendon (UCLA score, 34.2 and 27.6, respectively [ P < .05]; Constant score, 94 and 76, respectively [ P < .05])., Conclusion: The double-row repair technique potentially provides superior tendon healing compared with the single-row technique. Double-row repair should be considered for patients younger than 55 years with medium to large rotator cuff tears.

Background: To report the incidence of septic arthritis after anterior cruciate ligament (ACL) reconstruction and management of this complication using a specific treatment protocol., Methods: All primary ACL reconstructions performed in our institution between January 2002 and January 2014 were included in this study. Time to presentation, clinical symptoms, and culture results of all infected patients were analyzed. According to our protocol, an arthroscopic debridement and irrigation of the knee joint was performed immediately after a diagnosis of infection was made. In case of recurrence, knee irrigation with hardware and graft removal and later re-implantation was performed. Patients were evaluated with the Lysholm knee score, International Knee Documentation Committee (IKDC) Form, KT 1000 arthrometer and radiographic evaluation., Results: Postoperative septic arthritis occurred in seven of 1242 patients (0.56%). After initial arthroscopic debridement, infection recurred in six out of seven cases (85%). Graft and hardware removal was performed in these patients. Graft re-implantation was performed in four patients at an average five months after infection. At the final follow-up (mean 6.3years) all patients had full range of motion, while in patients with graft re-implantation the mean Lysholm score was 92, and the mean IKDC score was 87. Radiographs demonstrated that three patients had normal knees and one patient had a grade one, knee arthritis according to Kellgren-Lawrence classification., Conclusions: Management of septic arthritis after ACL reconstruction using a specific surgical protocol which includes graft removal in case of infection recurrence with later re-implantation, can provide good and excellent results., Level of Evidence: Level IV, case series., (Copyright © 2017 Elsevier B.V. All rights reserved.)