Our described technique for screw and washer removal is safe and simple, avoiding the risk of implant loss in the joint cavity.
Displaced tibial spine fractures are considered to be an indication for surgery.1 Arthroscopic reduction of the fracture and fixation with a cannulated screw and washer is 1 treatment option.2-4 When used in children, it may be necessary to remove the screw and the washer once the fracture has healed, especially if the screw is placed across the proximal tibial physis.3,5,6 At times, it may be necessary to exchange the screw during the index procedure for optimization of length. This article describes a safe and simple technique for arthroscopic removal of a cannulated screw and washer from the knee joint.
Materials and Methods
Since 2008, we have used this technique in 6 skeletally immature patients who had sustained a displaced tibial spine fracture. In 3 of 6 patients, this technique was used when an epiphyseal screw had to be exchanged for a transphyseal screw to obtain better purchase in the tibial metaphysis during the index procedure. All 6 patients with transphyseal screw fixation underwent removal of screw and washer using this technique approximately 3 months after their index procedure.
The patient is positioned supine on the operating table and the involved leg is placed in a leg holder with the hip in approximately 20° of flexion, so that C-arm access is possible if needed. The lower extremity is prepped and draped in the usual sterile fashion. Standard arthroscopic portals (superolateral outflow, anterolateral, and anteromedial) are established. The arthroscope is placed in the anterolateral portal. The anterior cruciate ligament, tibial spine, and screw are identified. A medial or lateral midpatellar portal (the one used to insert the screw during the index procedure) is then established. The midpatellar portal is located just off the medial or lateral edge of the midpatella at the widest portion of the patella. If the screw head is not readily visualized, C-arm fluoroscopy is used and the guide wire for a cannulated screw is placed into the screw through the midpatellar portal. The screw is backed out a few threads and the guide wire is withdrawn. The washer is freed from any surrounding soft tissues using a shaver and then elevated from the tibial spine using a grasper or a probe through the anteromedial portal.
Then, a 21-gauge spinal needle (preloaded and looped with 2-0 PDS suture) is placed through the anteromedial portal (Figure 1). The needle is placed through the washer (Figure 2). A grasper inserted from the midpatellar portal is used to retrieve 1 end of the looped suture. The spinal needle is withdrawn and the other end of the suture is retrieved from the midpatellar portal, such that the suture is looped around the washer (Figure 3). The screw and washer are withdrawn through the midpatellar portal while pulling on the suture.
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|Figure 1: The spinal needle is loaded and looped with 2-0 PDS. The suture should be looped around the blunt end of the needle to prevent cutting of the suture by the sharp beveled edge. Figure 2: The needle with its suture is inserted through the anteromedial portal and placed through the washer. The suture can be threaded in the needle once the needle is placed through the washer. |
|Figure 3: The 2 ends of the sutures are pulled out through parapatellar portal, thus establishing a loop around the washer. |
Prior to 2008, while attempting to remove a cannulated screw and washer from the knee joint in a patient, we inadvertently pulled out the guide wire after removing the screw. The grasper that was holding the washer slipped as an attempt was made to retrieve the washer from the anteromedial portal. The washer floated to the back of the knee, in the posterolateral compartment. A posterolateral portal had to be established to retrieve the washer, which involved extra time and effort. Since then, we have used the described arthroscopic technique for removal of the screw and washer. Using this surgical technique, 3 of 6 patients underwent exchange of the screw size to a longer screw during the index procedure, without difficulty. All 6 patients underwent removal of washer and screw at 3 months, using the described technique, without any complications. During removal of the screw and washer in 2 patients, the screw was rotating and not backing out; the pull of the suture through the washer helped to pull out the screw. The tibial spine fracture healed in all patients without any growth disturbances related to the proximal tibial physis.
Tibial spine fractures range from minimally (type I) to completely displaced (type III) as classified by Meyers and McKeever.1 Arthroscopic reduction and cannulated screw fixation is an acceptable technique for surgical stabilization of displaced tibial spine fractures.2-4 In children with open physes, an epiphyseal screw is recommended to avoid violation of the proximal tibial physis.4 If an epiphyseal screw does not permit adequate fixation, the screw can be placed through the proximal tibial physis. If the screw is placed transphyseal, it is advisable to remove the screw and the washer.3,5,6 The other possible indications for removal include impingement of the screw in the notch, loosening of the screw, future magnetic resonance imaging,3 patient interest,3 or theoretical risk of fretting corrosion between the screw and the washer.2
Veselko et al6 recognized the potential for problems associated with arthroscopic removal of cannulated screw and washer from the knee joint. They recommended that a grasper should push the screw and the washer over the guide wire out of the joint, and only then should the guide wire be removed. However, inadvertent removal of the guide wire or slippage of the grasper, as mentioned in our case, would create a loose object within the joint. Reynders et al2 reported on their experience with arthroscopic intrafocal cannulated screw fixation for pediatric and adolescent tibial eminence fractures. They did not have trouble during removal of the screw and the washer, as the washer was designed such that the inner diameter of the washer was less than the diameter of the screw thread; thus the washer cannot be dislodged while removing the screw.
Our described technique for screw and washer removal is safe and simple, avoiding the risk of implant loss in the joint cavity. This technique is similar to minimally invasive procedures where a suture is frequently tied around the screw head before its insertion to prevent its loss in deeper tissues. The PDS 2-0 suture can break if pulled hard, and a stronger suture can be used, although we have not felt the need. The suture can be threaded in the needle after the needle has been placed through the washer, or during insertion the suture can be placed around the washer outside the joint. The pull of the suture and washer in line with the screw will also help during difficult screw removal cases. The current technique can be used with noncannulated screws and washer, or in any other joints.
- Meyers MH, McKeever FM. Fracture of the intercondylar eminence of the tibia. J Bone Joint Surg Am. 1970; 52(8):1677-1684.
- Reynders P, Reynders K, Broos P. Pediatric and adolescent tibial eminence fractures: arthroscopic cannulated screw fixation. J Trauma. 2002; 53(1):49-54.
- Senekovic V, Veselko M. Anterograde arthroscopic fixation of avulsion fractures of the tibial eminence with a cannulated screw: five-year results. Arthroscopy. 2003; 19(1):54-61.
- Kocher MS, Foreman ES, Micheli LJ. Laxity and functional outcome after arthroscopic reduction and internal fixation of displaced tibial spine fractures in children. Arthroscopy. 2003; 19(10):1085-1090.
- Mylle J, Reynders P, Broos P. Transepiphysial fixation of anterior cruciate avulsion in a child. Report of a complication and review of the literature. Arch Orthop Trauma Surg. 1993; 112(2):101-103.
- Veselko M, Senekovic V, Tonin M. Simple and safe arthroscopic placement and removal of cannulated screw and washer for fixation of tibial avulsion fracture of the anterior cruciate ligament. Arthroscopy. 1996; 12(2):259-262.
Dr Parikh is from the Division of Pediatric Orthopedic Surgery, Cincinnati Childrens Hospital Medical Center, Cincinnati, Ohio.
Dr Parikh has no relevant financial relationships to disclose.
Correspondence should be addressed to: Shital N. Parikh, MD, 3333 Burnet Ave, ML 2017, Cincinnati, OH 45229 (email@example.com).