| Objective Anatomical methods are used to study the safe or dangerous zone of important vascular nerves in the anatomy around the knee joint,analyze the influence of different angles of knee flexion on the popliteal artery position,study the anatomical position and pathways of the common peroneal nerve and the relationship between the common peroneal nerve and important anatomical signs around the common peroneal nerve,so as to provide relevant theoretical and data support for clinical surgery.Methods Knee magnetic resonance imaging data were collected from 50 patients from the First Affiliated Hospital of Jiamusi University between January 2022 and December 2022.The exclusion criteria were cruciate ligament rupture,knee joint with severe deformity,knee tumor history,popliteal cyst history,knee surgery history and recent knee fracture history.The closest distance PA-LFC of the popliteal artery at the supracondylar level of femur(i.e.the transcondylar line)and the posterolateral condyle of femur was determined as a,the closest distance PA-MFC between the supracondylar level of femur(i.e.the transcondylar line)and the posterolateral condyle of femur was determined as b,and the closest distance PA-PC between the articular line and the posterior articular capsule was determined as c.The closest distance between the popliteal artery and the posterior tibial cortex at 1cm below the articular line was set as d;the closest distance between the popliteal artery and the posterior tibial cortex at 2cm below the articular line was set as e;meanwhile,the closest distance between the popliteal artery and the posterior tibial cortex on the sagittal plane was also measured as f.(2)Excluding specimens with severe lower extremity dysplasia,bone defects,knee joint trauma,bone tumors,peri-knee tissue necrosis,tuberculosis,and bony deformity,a total of 12 adult embalming specimens were used.The skin and subcutaneous fascia were removed layer by layer,the gastrocnemius was severed,the tibial nerve,popliteal vein and popliteal artery were stripped layer by layer,and the popliteal artery was observed and the popliteal artery was measured at different planes.The skin and subcutaneous tissue in front of the knee joint were released,and the knee joint was further bent to different angles to observe and measure the changes of the popliteal artery.The anatomical pathways of the common peroneal nerve near the knee joint was also observed on cadaver specimens,and the distance and angle between Gerdy tubercle and the common peroneal nerve and its branches were measured.Results(1)a,b,c,d,e and f were(4.69±1.76)mm,(6.04±1.82)mm,(4.26±1.23)mm,(3.74±1.37)mm,(3.46±1.44)mm and(3.28±1.09)mm,respectively.The triangular danger zone formed by the popliteal artery and its branches.Behind the triangle on the coronary plane is the densely distributed zone of the main popliteal artery,the external inferior knee artery,the median knee artery and the innominate branch.These vessels are close to the rear of the joint capsule and are easily damaged during surgery.Before the knee curvature of 45°,the distance of a,b,c,d,e and f layers did not change significantly.Except for the proximal distance between the femoral condyle and the posterior medial condyle of the femur gradually shortened after the knee curvature of 45°,the other layers tended to increase gradually from 45° to 90°.When the bend exceeds 90 degrees,a and f appear as a shortened distance.(2)The common peroneal nerve enters the popliteal fossa laterally and pathways the upper lateral margin of the popliteal fossa,i.e.the medial side of the biceps femoris tendon.It crosses the lateral head tendon of the gastrocnemius and runs down and out between the biceps femoris tendon and the lateral head of the gastrocnemius to the rear of the head of the fibula,then goes around the back of the neck of the fibula and forwards through the origin of the peroneus longus and divides into the superficial peroneal nerve and the deep peroneal nerve to supply the tibialis anterior and lateral muscles of the calf,and at the upper end of the peroneal canal there is a constant recurrent knee nerve running horizontally towards the knee joint.The distance(GA)from the vertex of Gerdy tubercle to the junction of the common peroneal nerve and the posterior peroneal head was(39.3±0.9)mm,and the distance(GB)from the vertex of Gerdy tubercle to the beginning of the superficial peroneal nerve was(40.6±1.3)mm.The distance(GC)from the vertex of Gerdy tubercle to the proximal tibia of the recurrent genicular nerve of the anterior peroneal nerve was(39.3±0.9)mm.With the vertex of the Gerdy tubercle as the origin of rotation,the connection between the apex of the Gerdy nodule and the common peroneal nerve behind the head of the fibula is a 0° line with a radius of 40 mm.When rotated to 35°,the origin of the superficial peroneal nerve can be marked.The remaining rotating arc reaches 94 ° and approaches the tibia,which is the path of the anterior recurrent geniculate nerve of the common peroneal nerve.Conclusions(1)There is a triangular danger zone behind the knee that lacks adequate soft tissue to protect vital nerve vessels.When bending at different angles,the position of the popliteal artery will change either far or near.Therefore,for reducing the risk of popliteal artery injury during TKA surgery,adequate protection rather than flexion should be adopted.(2)Except for the medial condyle of femur,the average distance between the popliteal artery in the popliteal fossa and the lateral condyle of femur,the posterior articular capsule and the posterior cortex of tibia is less than 5mm.And the popliteal artery in the popliteal fossa is almost all located in the medial lateral of the center in different planes,so the operator is relatively safe when operating in the medial region of the operative area.(3)The common peroneal nerve bypassing the fibula neck behind the fibula head is divided into superficial peroneal nerve and deep peroneal nerve branch,The deep peroneal nerve branch and the recurrent knee nerve at the upper end of the peroneal canal.By using the Gerdy nodule as a marker point,the trajectory of the common peroneal nerve and its branches at the proximal tibia can be delineated,and the relative safe zone of surgery can be determined. |
