Safe femoral pin placement in knee navigation surgery: A cadaver study

Abstract

A number of navigation systems used for total knee replacement surgery currently require the insertion of a distal femoral reference sensor pin, which is placed anterior to posterior just superior to the level of the knee joint. There is potential for the posterior neurovascular bundle to be damaged during the insertion of this sensor device. The aim of this cadaveric study was to identify the structures at risk during insertion of the distal femoral sensor, and determine whether a safe zone for insertion could be identified. Sixteen cadaveric lower limbs (8 pairs) were studied. In each knee Steinman pins were passed from anterior to posterior, 5 cm proximal to the level of the femoral articular cartilage, directly AP and angled at 30 degrees passing medially or laterally. All pins that were passed directly from anterior to posterior and from lateral to medial passed within 5 mm of a major neurovascular structure, while 62.5% of pins passing from medial to lateral passed within 5 mm of a major neurovascular structure. The popliteal vessels and the sciatic nerve are at risk of injury from a navigation pin or drill placed in the distal femur during knee navigation. Caution should be exercised in passing these pins and alternate methods of fixing femoral sensors should be considered.

Femoral Shaft Fracture Resulting From Femoral Tracker Placement in Navigated TKA

“…In one anatomic study, the findings indicated the close proximity of the popliteal vessels to potential injury with bicortical placement of tracker pins in the anteroposterior direction in typical total knee approaches [13]. They reported that 100% of pins placed in the distal femur from anterolateral to posterior medial were within 5 mm of the popliteal artery and vein.…”

Transepicondylar distal femoral pin placement in computer assisted surgical navigation

“…It is therefore essential to have a clear understanding of the relationship between the neurovascular structures posterior to the knee joint when considering surgery in this area. Marchant et al [15] observed the existence of a definite, reproducible risk to the popliteal neurovascular structures when placing a bicortical reference pin. The popliteal artery and vein were observed to be most at risk due to their apparent intimate relationship to the posterior femoral cortex.…”

“…Furthermore, the potential for damage to neurovascular structures during knee surgery has been identified [9][10][11][12][13][14]. Marchant et al demonstrated that 100% of pins placed in the distal femur from anterolateral to posterior medial were within 5 mm of the popliteal artery and vein [15].…”

Blocking Screws: An Adjunct to Retrograde Nailing for Distal Femoral Shaft Fractures

“…Furthermore, there may be a risk of injuring the patellofemoral joint and neurovascular bundle while placing the blocking screws in an anteroposterior direction. 2,3 Does the screw location differ depending on the pattern of the fracture? What was the authors' view regarding this issue?…”