Christian Sobau

Radiographic analysis of Re-Ruptures of reconstructed ACLs - Evaluation of tunnel position as a possible cause of Failure

Objectives: Previous studies detected femoral and / or tibial tunnel malpositioning as possible causes for the failure of an anterior cruciate ligament reconstruction. We investigated various radiological angles and criterias for ACL revision surgery to find possible causes for the failure of the primary reconstructed ACLs based on digital X-ray images. Materials and Methods: 529 ACL revisions after previous reconstruction were carried out between 1993 and 2013, of which we were able to include 100 patients with digital radiographs in our study. We investigated the angles of the femoral and tibial tunnel position in the coronal and sagittal plane. Furthermore we analyzed the entry point on the femur in accordance with the quadrant method described by Bernard and Hertel. We divided into: A) adequate trauma (n = 87) and non-trauma group (n = 13); B) Hamstring (n = 76) and Patella-BTB group (n = 24); C) transtibial (n = 83) and anteromedial group (n = 17). In addition we built subgroups B1/C1 adequate re-trauma or B2/C2 no adequate trauma to analyze whether there were differences in these groups. Results: The trauma group differed significantly from the non-trauma group in the measured angle of the tibial tunnel in the ap radiograph (trauma group 28.4°, non-trauma group 22.67°; p = 0.013). The Hamstring group differed significantly from the BTB group in the measured inclination angle of the femoral tunnel in the ap radiograph (HS group 54.86°, BTB group 62.78°; p = 0.015). There was also a significant difference concerning the tibial tunnel in the ap radiograph (HS group 29.56°, BTB group 21.63°; p = 0.0001). Comparing the two groups for the femoral tunnel placement-techniques we could find significant differences in the femoral ap-radiographs (inclination angle: TT = 59.04°, AM = 45.64°; p = 0.0001). The analysis of the 4 subgroups revealed differences in the tibial ap images: The BTB trauma group had an average of 23.56° relative to the BTB non-trauma group of 16.91° (p=0.013). The HS groups among themselves did not differ significantly, but the HS non-trauma group had a significantly higher angle with 29.38° to 16.91° in the BTB non-trauma group (p = 0.0003). In addition there was a significant difference when comparing the transtibial trauma group with the transtibial non trauma group (TT trauma = 27.66°, TT non trauma = 21.15°; p = 0.017) Conclusion: Overall we could only find a few significant differences in the measured angles and only a few deviations from the values described within the literature. Therefore a real trauma was necessary to rupture the reconstructed ACL in 87%. In 13% we could find a possible cause within the tibial tunnel: the steeper the tibial tunnel was, less trauma was necessary for failure, especially when using the transtibial drilling method or Patella-BTB grafts. However the small sample size limits the results therefore further studies are necessary.

Femoral neck fracture is a rare complication after arthroscopic femoroplasty for femoroacetabular impingement with no known prognostic factors and few reported risk factors: a systematic review

Importance Arthroscopic hip surgery established itself as a therapeutic option for the surgical treatment of hip diseases. There have been few reports about postoperative femoral neck fractures. We give an overview of risk factors that could lead to femoral neck fracture because existing reports of risk factors such as gender and fracture rates are oppositional in the recent literature. Objectives This work aims to systematically review the current available articles reporting on the rare complication of femoral neck fractures after hip arthroscopy and/or arthroscopic femoroplasty mainly treating femoroacetabular impingement. Particularly, the questions that the authors aimed to answer were (1) What are the fracture rates after hip arthroscopy and/or arthroscopic femoroplasty? (2) Are there any negative prognostic factors that may lead to femoral neck fractures? Evidence review The EMBASE, MEDLINE and PubMed databases were searched for articles addressing femoral neck fractures after arthroscopic femoroplasty. Articles selected in this review met six inclusion criteria. Descriptive statistics from the eight studies identified by the search were analysed. Findings Fracture rates ranged from 0.07% to 1.9%. All publications demonstrated that risk increases with age. One study identified male sex as a risk factor, another found females were at risk. Another factor seems to be—at least for men—greater height. Two case reports showed increased risk with increased bone resection, one of which demonstrated that a resection depth ratio of >18% leads to a 25-fold increased risk of fracture. Conclusion and relevance The fracture rate after hip arthroscopy is 0.08% and 0.12% after arthroscopic femoroplasty. Patients likely to be at risk are older than 45 years and/or tall men. Bone resection depth is one of the main risk factors. Male patients seem to have a minimally higher risk, but it is not yet clear whether sex is a risk factor. There is a lack of high-level evidence. Further research needs therefore to be done. Level of evidence Level IV, systematic review of level II, III and IV studies.