Study of vorticity in an exact rotating hydro model

We study a semianalytic exact solution of the fluid dynamical model of heavy ion reactions, and evaluate some observable signs of the rotation.Comment: 19 pages, 6 figures. arXiv admin note: substantial text overlap with arXiv:1406.101

Ultrasound-Assisted Endoscopic Removal of Pretibial Cysts Related to Biointerference Screw Degradation

We report on the treatment of cases of painful subcutaneous pretibial cyst due to broken and displaced materials of only partly absorbed bioabsorbable interference screws used for anterior cruciate ligament reconstruction. Ultrasound examination was used to both make the definite diagnosis and determine the exact localization of dislodged screw parts. The broken and loose bioabsorbable screw parts and surrounding cyst-like structure were removed endoscopically by a soft-tissue resector.publishedVersio

Clinical outcome after mosaicplasty of knee articular cartilage defects of patellofemoral joint versus tibiofemoral joint

Background The purpose was to investigate survival of cartilage repair in the knee joint by osteochondral autograft transfer stratified by location of the lesion; patellofemoral joint (N = 26) versus the medial or lateral femoral condyles (N = 58). Methods For survival analyses, “failure” was defined as the event of a patient reporting a poor Lysholm score (below 65 points) or undergoing a knee replacement procedure. Results The survival distribution was not significantly different between the patellofemoral joint and the tibiofemoral joint groups. Conclusions The current study suggest that similar long-term outcome can be expected after OAT procedures for the patellofemoral or tibiofemoral joint.publishedVersio

Failed meniscal repairs after anterior cruciate ligament reconstruction increases risk of revision surgery

Background: Failed anterior cruciate ligament (ACL) reconstruction (ACLR) can lead to reduced quality of life because of recurrent episodes of instability, restrictions in level of activity, and development of osteoarthritis. A profound knowledge of the causes of a failed surgery can ultimately help improve graft survival rates. Purpose: To investigate the patient-related risks of inferior outcomes leading to revision surgery after ACLR. Study Design: Case-control study; Level of evidence, 3. Methods: From a prospective cohort of primary ACLRs performed at a single center, patients who required later revision surgery were matched with a control group of uneventful primary ACLRs. Patient characteristics, data from the preoperative examinations, KT-1000 arthrometer laxity testing, Tegner activity scale, International Knee Documentation Committee subjective score, Knee injury and Osteoarthritis Outcome Score, and perioperative data from the initial surgery were included. Results: A total of 100 revision cases and 100 matched controls, with a median follow-up time of 11 years, were included in the study. Those who had undergone revision surgery were younger at the time of reconstruction and had a shorter time from injury to surgery than their matched controls (P = .006). The control group—of uneventful ACLRs—had a higher incidence of meniscal repair at reconstruction (P = .024). Also, the revision group more frequently experienced later failure of the previous meniscal repair (P = .004). Surgeon experience was not found to affect the risk of revision ACL surgery. Those who had undergone ACL revision surgery had more frequently received a hamstring tendon graft size of <8 mm (P = .018) compared with the controls. Conclusion: The current study demonstrated that failed meniscal repair and a hamstring tendon graft size of <8 mm were associated with primary ACLR failure. Also, younger age at the time of surgery and shorter time from injury to surgery were found to affect the risk of undergoing revision ACL surgery.publishedVersio

Incidence and Prognostic Significance of the Segond Fracture in Patients Undergoing Anterior Cruciate Ligament Reconstruction

Background: The Segond fracture is an avulsion of the anterolateral tibia that can be found in patients with an anterior cruciate ligament (ACL) tear. It is currently unclear if the Segond fracture needs treatment or if it heals spontaneously and if it is associated with an increased risk of failure after ACL reconstruction. Purpose: To identify the incidence and spontaneous healing rate of Segond fractures in a consecutive cohort of patients undergoing ACL reconstruction and to examine the predictive value of the Segond fracture on the risk of undergoing revision surgery. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective review of a cohort undergoing isolated ACL reconstruction between 2002 and 2016 was performed. Radiographs from the time of injury and preoperative radiographs were evaluated for Segond fractures and healed Segond fractures. Descriptive data were extracted from an internal quality database. Statistical analyses were performed to investigate risk of revision surgery and to compare across subgroups of patients. Results: A total of 1364 patients were included in the study. The incidence of Segond fractures was 7.4%. In addition, 10.4% of patients displayed signs of healed Segond fractures. In total, 15.2% of patients had either 1 or both findings. The overall healing response of the fracture was 35.6%. Those with Segond fractures were older (P = .014) and had a shorter interval from injury to surgery (P = .003) as compared with the rest of the cohort. The incidence of Segond fractures was significantly higher in those injured during downhill skiing as compared with other injury mechanisms (P = .04). The Segond fracture did not represent an increased risk of undergoing revision when compared with the control group (not significant). Conclusion: The incidence of conventional Segond fractures in patients with ACL injury was found to be in accordance with former studies. Accounting for the high incidence of healed Segond fractures, a much higher incidence (15%) was seen. Although the spontaneous healing rate from initial radiographs to preoperative imaging was only 36%, the presence of Segond fractures did not represent a higher risk of undergoing revision surgery.publishedVersio

Fracture-related infection: Prevalence and application of the new consensus definition in a cohort of 1004 surgically treated ankle fractures

Background Surgical treatment of ankle fractures comes with a substantial risk of complications, including infection. An unambiguously definition of fracture-related infections (FRI) has been missing. Recently, FRI has been defined by a consensus group with a diagnostic algorithm containing suggestive and confirmatory criteria. The aim of the current study was to report the prevalence of FRI in patients operated for ankle fractures and to assess the applicability of the diagnostic algorithm from the consensus group. Patients and methods Records of all patients with surgically treated ankle fractures from 2015 to 2019 were retrospectively reviewed for signs of postoperative infections. Patients with suspected infection were stratified according to confirmatory or suggestive criteria of FRI. Rate of FRI among patients with confirmatory and suggestive criteria were calculated. Results Suspected infection was found in 104 (10%) out of 1004 patients. Among those patients, confirmatory criteria were met in 76/104 (73%) patients and suggestive criteria were met in 28/104 (27%) at first evaluation. Patients with clinical confirmatory criteria (N = 76) were diagnosed with FRI. Patients with suggestive criteria were further examined with either bacterial sampling at the outpatient clinic, revision surgery including bacterial sampling, or a wait-and-see approach. Eleven (39%) of the 28 patients had positive cultures and were therefore diagnosed as having FRI at second evaluation. In total 87 (9%) patients were diagnosed with FRI according to the consensus definition. Only 73 (70%) of the 104 patients with suspected FRI had adequate bacterial sampling. Conclusion The prevalence of FRI, applying the FRI-consensus criteria, for patients with surgically treated ankle fractures was 9%. Twenty-two percent of patients who met the confirmatory criteria had negative bacterial cultures. The current study shows that we did not have a systematic approach to patients with suspected FRI as recommended by the consensus group. A systematic approach to adequate bacterial sampling when FRI is suspected is paramount. The consensus definition of FRI and its diagnostic algorithm facilitates such an approach.publishedVersio

The Effect of Posterior Tibial Slope on the Risk of Revision Surgery After Anterior Cruciate Ligament Reconstruction

Background: A significant proportion of patients undergoing anterior cruciate ligament (ACL) reconstruction (ACLR) later experience graft failure. Some studies suggest an association between a steep posterior tibial slope (PTS) and graft failure. Purpose: To examine the PTS in a large cohort of patients about to undergo ACLR and to determine whether a steep PTS is associated with later revision surgery. Study Design: Case-control study; Level of evidence, 3. Methods: A retrospective review of a cohort undergoing isolated ACLR between 2002 and 2012 (with 8-19 years of follow-up) was conducted. Preoperative sagittal radiographs of knees in full extension were used for measurements of the PTS. There were 2 independent examiners who performed repeated measurements to assess the reliability of the method. Statistical analyses were performed to compare the PTS in the groups with and without later revision surgery. Results: A total of 728 patients, with a mean age of 28 years at the time of surgery, were included. Overall, 10% (n = 76) underwent revision surgery during the observation period. The group of injured knees had a significantly steeper PTS compared with the group of uninjured knees (9.5° vs 8.7°, respectively; P < .05). The mean PTS in the no revision group was 9.5° compared with 9.3° in the revision group (not significant). Dichotomized testing of revision rates related to PTS cutoff values of ≥10°, ≥12°, ≥14°, ≥16°, and ≥18° showed no association of PTS steepness (not significant) to graft failure. Patients with revision were younger than the ones without (mean age, 24 ± 8 vs 29 ± 10 years, respectively) and had a shorter time from injury to ACLR (mean, 14 ± 27 vs 24 ± 44 months, respectively) as well as a smaller graft size (8.2 vs 8.4 mm, respectively; P = .040). Conclusion: The current study did not find any association between a steep PTS measured on lateral knee radiographs and revision ACL surgery. However, a steeper PTS was seen in the group of injured knees compared with the group of uninjured (contralateral) knees. Independent of the PTS, younger patients, those with a shorter time from injury to surgery, and those with a smaller graft size were found to undergo revision surgery more often.publishedVersio

Insall proximal realignment with/without tibial tubercle osteotomy for recurrent patellar instability yields acceptable medium- to long-term results but risk of osteoarthritis progression is considerable

Purpose: The purpose of this study was to evaluate clinical and radiological results in patients operated for recurrent patellar instability with a surgical approach consisting of Insall proximal realignment with/without tibial tubercle osteotomy (TTO). Methods: Patients that underwent surgery for recurrent patellar instability at one centre with a uniform technique between 2004 and 2020 were included. Eligible patients were assessed by clinical examination and the disease-specific Banff Patellofemoral Instability Instrument 2.0 (BPII 2.0). Pre- and postoperative radiographs were analysed for patellofemoral osteoarthritis (OA) according to Iwano. Preoperative Magnetic Resonance Imaging (MRI) and radiographs were analysed for anatomical risk factors for patellar instability. Student t-test, chi-square test and ANOVA-analyses were used to investigate whether anatomical risk factors and/or patient characteristics could predict an inferior outcome. Results: Forty-six patients (47 knees) were included at a mean follow-up time of 6.6 years (SD 4.6; range 1–17). Mean BPII 2.0 score was 60.4 (SD 18.4; range 26–98), and 10.6% (n = 5) had suffered a postoperative redislocation. Progression to evident patellofemoral OA was seen in 15% of the patients (p < 0.05). The presence of pathoanatomic risk factors did not correlate with recurrent postoperative instability or inferior BPII 2.0 score at the final evaluation. Conclusion: Patients treated with the current approach reported acceptable medium- to long-term results, but the risk of patellofemoral OA progression is significant. These findings add to the knowledge of expected outcomes after procedures involving Insall proximal realignment, and can guide clinical decision making for surgeons using similar methods.publishedVersio