A computed tomography cadaveric study of the radiological anatomy of the patella: the size of the patella correlates with bone bridge between tunnels and R angles are introduced for safe tunnel drilling during MPFL reconstruction

Autor: Vasileios Raoulis, Ioannis Tsifountoudis, Apostolos Fyllos, Michael Hantes, Michael‐Alexander Malahias, Apostolos Karantanas, Aristeidis Zibis
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Journal of Experimental Orthopaedics, Vol 8, Iss 1, Pp n/a-n/a (2021)
Druh dokumentu: article
ISSN: 2197-1153
DOI: 10.1186/s40634-021-00348-9
Popis: Abstract Purpose To measure the safe range of angles during tunnel drilling and map ideal patella tunnel placement with the use of preoperative computed tomography (CT) scan and compare results after medial patellofemoral ligament (MPFL) reconstruction using a hardware‐free patellar fixation technique with two semi‐patellar tunnels between a) a free‐hand technique, and b) its modification with the use of an anterior cruciate ligament (ACL) tibia aiming device. Methods CT scan was performed on 30 fresh‐frozen cadaveric knees a) prior to any intervention and b) after MPFL reconstruction. For MPFL reconstruction, specimens were randomly allocated to 1) Group A, which consisted of knees operated with free‐hand, hardware‐free patellar fixation technique with two semi‐patellar tunnels and 2) Group B, which consisted of knees operated on with a technique modification with the ACL tibia device. Patellar measurements L1 was the maximal patellar length. L2 was the minimum possible distance of placement for the upper tunnel from the proximal pole of the patella. The maximum bone bridge between tunnels was calculated as half of L1 minus the L2 distance (L1/2‐L2). We also measured R1 and R2 angles at the proximal and distal tunnel that represent safe angles at the entry point during tunnel drilling (without breaching the anterior cortex or articular cartilage). Results Preoperatively, mean L1 was 3.45 cm (range 3.05–4.52). Mean L2 was 0.62 cm (range 0.49–0.89). The mean maximum possible bone bridge between tunnels (L1/2‐L2) was 1.1 cm (range 0.77–1.58). R1 was 6.050 (range 4.78–7.44), R2 was 6.640 (range 4.57–9.03), and their difference reached statistical significance (p = 0.03). Postoperatively, in group A, in 4 out of 15 patellas, multiple attempts were made during tunnel drilling in order to avoid anterior cortex or cartilage breaching. In group B, all tunnels were correctly drilled with the first attempt. Bone bridge between tunnels was significantly shorter postoperatively (0.93 cm, p
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