Guido Wierer1,2, Philipp W Winkler3, Werner Pomwenger4, Fabian Plachel5,6, Philipp Moroder6, Gerd Seitlinger7. 1. Department of Orthopedics and Traumatology, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, 5020, Salzburg, Austria. wierer@gmail.com. 2. Research Unit for Orthopaedic Sports Medicine and Injury Prevention, Institute for Sports Medicine, Alpine Medicine and Health Tourism (ISAG), UMIT, Eduard-Wallnöfer-Zentrum 1, 6060, Hall in Tirol, Austria. wierer@gmail.com. 3. Department for Orthopaedic Sports Medicine, Klinikum Rechts Der Isar, Technical University of Munich, Ismaninger Str. 22, 81675, Munich, Germany. 4. Department of Information Technology & Systems, Salzburg University of Applied Sciences, Urstein Süd 1, 5412, Puch bei Salzburg, Austria. 5. Department of Orthopedics and Traumatology, Paracelsus Medical University Salzburg, Müllner Hauptstraße 48, 5020, Salzburg, Austria. 6. Center for Musculoskeletal Surgery, Charité -Universitatsmedizin Berlin, Augustenburgerplatz 1, 13353, Berlin, Germany. 7. Orthofocus, Guggenbichlerstrasse 20, 5026, Salzburg, Austria.
Abstract
PURPOSE: (1) To determine applied patellar drilling techniques for medial patellofemoral ligament (MPFL) reconstruction among members of the International Patellofemoral Study Group (IPSG) and (2) to evaluate the risk of patellar fracture for various patellar bone tunnel locations based on a finite element analysis (FEA) model. METHODS: In the first part of the study, an online survey on current MPFL reconstruction techniques was conducted among members of the IPSG. In the second part of the study, a three-dimensional FEA model of a healthy knee joint was created using a computed tomography scan. Patient-specific bone density was integrated into the patella, and cartilage of 3 mm thickness was modeled for the patellofemoral joint. According to the survey's results, two different types of patellar bone tunnels (bone socket and transpatellar bone tunnel) were simulated. The risk of patellar fracture was evaluated based on the fracture risk volume (FRV) obtained from the FEA. RESULTS: Finite element analysis revealed that subchondral bone socket tunnel placement is associated with the lowest FRV but increased with an anterior offset (1-5 mm). Transpatellar bone tunnels violating the lateral or anterior cortex showed a higher FRV compared to bone socket, with the highest values observed when the anterior cortex was penetrated. CONCLUSION: Violation of the anterior or lateral patellar cortex using transpatellar bone tunnels increased FRV compared to a subchondral patellar bone socket tunnel. In MPFL reconstruction, subchondral patellar bone socket tunnels should be considered for patellar graft fixation to avoid the risk of postoperative patellar fracture. LEVEL OF EVIDENCE: Survey; Descriptive laboratory study/Level V.
PURPOSE: (1) To determine applied patellar drilling techniques for medial patellofemoral ligament (MPFL) reconstruction among members of the International Patellofemoral Study Group (IPSG) and (2) to evaluate the risk of patellar fracture for various patellar bone tunnel locations based on a finite element analysis (FEA) model. METHODS: In the first part of the study, an online survey on current MPFL reconstruction techniques was conducted among members of the IPSG. In the second part of the study, a three-dimensional FEA model of a healthy knee joint was created using a computed tomography scan. Patient-specific bone density was integrated into the patella, and cartilage of 3 mm thickness was modeled for the patellofemoral joint. According to the survey's results, two different types of patellar bone tunnels (bone socket and transpatellar bone tunnel) were simulated. The risk of patellar fracture was evaluated based on the fracture risk volume (FRV) obtained from the FEA. RESULTS: Finite element analysis revealed that subchondral bone socket tunnel placement is associated with the lowest FRV but increased with an anterior offset (1-5 mm). Transpatellar bone tunnels violating the lateral or anterior cortex showed a higher FRV compared to bone socket, with the highest values observed when the anterior cortex was penetrated. CONCLUSION: Violation of the anterior or lateral patellar cortex using transpatellar bone tunnels increased FRV compared to a subchondral patellar bone socket tunnel. In MPFL reconstruction, subchondral patellar bone socket tunnels should be considered for patellar graft fixation to avoid the risk of postoperative patellar fracture. LEVEL OF EVIDENCE: Survey; Descriptive laboratory study/Level V.
Authors: Jonathan French; Patrick Huber; Joseph McShane; Cyndi L Holland; Robert J Elbin; Anthony P Kontos Journal: Am J Sports Med Date: 2019-10-14 Impact factor: 6.202
Authors: Philipp W Winkler; Nyaluma N Wagala; Sabrina Carrozzi; Ehab M Nazzal; Michael A Fox; Jonathan D Hughes; Bryson P Lesniak; Dharmesh Vyas; Stephen J Rabuck; James J Irrgang; Volker Musahl Journal: Knee Surg Sports Traumatol Arthrosc Date: 2022-01-14 Impact factor: 4.114