Medical Center, thank you to AOSSM and the forum for having me be part of this conference. I'm gonna be talking about mind the gap, managing tibial spine injuries with non-operative management, sutures, or screw fixation. Tibial spine avulsion fractures typically occur in patients eight to 14 years old due to rapid deceleration or hyperextension with rotation injuries, similar to ACL tears in older patients. They represent 2% to 5% of knee injuries in pediatric patients with a traumatic effusion. The ossification patterns of the immature skeleton might predispose these younger patients to this injury. In the skeletally immature patient, the intercondylar region is incompletely ossified, and thus it is weaker than the ACL complex. Displaced fractures are more likely in young patients under 11 and a half years old. Higher patient body mass index has also been associated with higher grade fracture severity, and this can include propagation of the fracture into the medial tibial plateau. Meyers and McKeever is the most commonly used classification system, although others have recently been proposed based on MRI images. This classification is based on fracture displacement measured on a lateral X-ray. The type one fracture as seen here is non-displaced. On this MRI, you can see that the ACL has some stress injury to it with some increased signal, and that there's a fracture of the ACL attachment, but that the fracture is relatively non-displaced. The type two fracture is minimally displaced, but the key feature is that it has an intact posterior hinge as can be seen here on the lateral X-ray. A type three fracture is a completely displaced fracture seen here in the diagram as well as on the lateral X-ray in the middle. The type four is similar, except there's some associated combination or a fragment that is completely flipped. Non-operative treatment is generally elected for type one non-displaced fractures and reducible type two fractures. A lateral X-ray is used to confirm reduction, and COX rays are key to confirm maintenance of alignment. Patients are treated in a cast or a hinged knee brace with the knee in extension for the first three to four weeks followed by gradual increase of range of motion with physical therapy. Operative treatment is indicated for non-reducible type two fractures and all type three and four fractures. Here on this X-ray, you can see a cast in type two fracture that failed to reduce with knee extension. Type two fractures might be non-reducible due to an entrapped intermeniscal ligament or a medial meniscus seen here on this sagittal MRI. The anterior horn of that medial meniscus is under the fracture fragment, or it can be due to the pull of the lateral meniscus attachment as seen here on the coronal MRI. That lateral meniscus attachment is often intact, and it makes seeing the fracture on the lateral aspect difficult at the time of surgery. Both of these problems can lead to a block to extension. It is essential for the treating surgeon to recognize that tibial spine fractures do not occur in isolation, but rather they're frequently accompanied by concomitant injuries. Reported rate of concomitant injuries has ranged from 40 to 68%. Early knowledge of concomitant injuries with a preoperative MRI can help with case planning. A recent study by the tibial spine fracture research interest group from PRISM found that 35% of patients who underwent an MRI after sustaining a tibial spine fracture had a concomitant injury identified. And 87% of those injuries required further operative management. The authors suggested that concomitant soft tissue and cartilaginous injuries might go undiagnosed in some patients who do not undergo advanced imaging, especially those treated with a closed reduction or a mini open approach. In a series by Coker et al, there was a 54% rate of meniscal entrapment, and type three fractures had a significantly higher proportion of meniscal entrapment. The authors identified a key decision factor for type two fractures was whether or not they reduced an extension, indicating that meniscal entrapment was unlikely. The treatment of type two fractures remains controversial. It was conflicting data regarding optimal management. The PRISM rig recently published a cross-sectional study assessing the variability among pediatric orthopedic surgeons when treating type two tibial spine avulsion fractures. Respondents selected operative management for 85% of cases. Surgeons were 28% more likely to treat operatively with each additional millimeter of displacement. And over 64% of surgeons chose to treat operatively when the fracture was displaced by more than three and a half millimeters. So this seems to be the threshold. Surgeon training, years in practice, and risk-taking scores were not associated with the respondent's preference for surgical treatment. So type two fractures are controversial, but what about type one fractures? A recent study also published by the PRISM rig reviewed 164 type one fractures. 25% of these patients had a clinically significant concomitant injury that required operative intervention, most commonly an ACL tear requiring reconstruction or a meniscal injury requiring repair or partial mastectomy. This study highlights that an MRI is imperative even for type one fractures. In a retrospective multi-center cohort study also by the PRISM rig, looking at type two fractures, patients treated non-operatively had more ACL laxity, a higher rate of subsequent new tibial spine fractures and ACL injuries that required surgery. The operative group did have a higher rate of arthrofibrosis, however. There was no difference in overall complication rate, re-operation rate, or final range of motion. There's no gold standard method for fixation, the treatment approach dictated by the patient, fracture, and concomitant injury characteristics, as well as surgeon preference. Biomechanics studies do show that sutures have a higher peak failure and pull-out strength when compared to cannulated screws. Suture fixation, although technically demanding, allows for minimal damage to the phisis, early mobilization, the ability to tension the ACL fibers, and can be used even with small or comminuted fragments. There's no second surgery required for removal of hardware, and there's less imaging artifact if a subsequent MRI is needed. Screw fixation requires a large fragment and unfortunately necessitates a second surgery for screw removal in the vast majority of cases. And it has the potential for physio damage if the screw crosses that physis, as well as screw impingement with knee extension. Caledon et al looked at 68 tibial spine fractures. Half of these were fixed with suture fixation and half had screw fixation. The suture group had a shorter time to radiographic union, which was interesting, as well as shorter follow-up required due to this earlier healing. There was increased elevation of the fragment in the suture group, but this was shown to not have any change in the surgical outcomes. Screw fixation, as expected, had more reoperations, mostly for plant implant removal. In a group of skeletally munture patients, Pan et al showed that arthroscopic screw fixation led to better IKDC scores, a lower incidence of postoperative pivot glide, and shorter OR time. So let's move on to surgical techniques. Arthroscopic fixation techniques begin with an assessment of the fracture fragment. Here on this arthroscopic image, you can see that the fragment does not reduce in full extension. In this case, it was due to an entrapped medial meniscus. To reduce this block to reduction, an 18-gauge needle, spinal needle, can be used in the outside-in technique to insert a non-braided suture under the anterior horn of the meniscus or the intermeniscal ligament. This can then be used as a retraction suture to aid in reduction. Next, the fracture bed is debrided, and it is advised to aggressively debride the fracture bed to allow for a recession of the fracture fragment into that fracture bed. This can allow increased tension in the ACL so that you can restore some of the resting ACL tension. And this is really helpful, especially given the ACL stretch that often accompanies these tibial spine fractures. Screw fixation should only be considered when the fracture fragment is large enough. Guide wires from a 4L cannulated screw system can be placed from a superior medial or superior lateral portal, and this is best created within the 90 degrees of flexion. Additional wires can be useful to prevent fragment rotation during screw insertion. The screw trajectory should be angled a little bit from anterior to posterior, close to perpendicular to the fracture fragment. A lateral fluoroscopic image intraop is essential to avoid placing the screw across the fasces and to assess the angle of the plant fixation, the length of the plant screw, as well as reduction of the fracture fragment. Care must be taken not to flex or extend the knee while the guide wires are in place to get that lateral x-ray to avoid bending those guide wires. A key tip is to tie a suture around the washer if you're using a washer and around the screw as well to prevent loss of that screw during screw insertion so that you don't lose the hardware in the knee joint itself. You can also use the screwdriver without the screw holder so that the incision can be smaller for screw insertion. The screw should be seated to the spine, but careful not to strip the screw in that soft metaphyseal bone. If using a washer, that washer can help compress that fracture fragment down to the tibial spine. Another tip is to cut the sutures that are on the washer and or the screw with a little bit of a tail so that they're easily identifiable at the time of hardware removal. Pre-op injury films and a lateral x-ray post-op after screw fixation can be seen here. And it is key to note that the screw threads do not cross that proximal tibial thysis. Moving on to suture fixation. If the fragment is large enough, a provisional K wire can be placed to stabilize the fracture, but this is not always necessary and it's often not possible if the fragment is small or comminuted. Next, a tibial ACL cut is used to place two drill tunnels from the anteromedial tibia to the base of the fracture. Houston suture passers then pass through the drill tunnels. A suture lasso is then used to pass non-absorbable suture through the base of the ACL. Absorbable sutures can be considered if there's a desire for temporary fixation to minimize physeal tethering, although no study has shown this to be a problem with potential growth arrest or angular deformity. A trans-patellar working portal is needed for suture retrieval. With the camera in the lateral portal, the suture lasso is used via the medial portal and the first pass is through the medial hewson, through the ACL from a medial to lateral direction and then through the lateral hewson. Ideally, the second suture is passed through the lateral hewson first, then through the ACL, also from a medial to lateral direction so that you can have some good spread from the first suture and then it is retrieved through the medial hewson often with a Kingfisher or a Grasper. When the sutures are then shuttled through the drill tunnels with the hewson suture passers, this will create an X configuration over the anterior aspect of the avulsion fragment and this will aid in maintaining fracture reduction similar to the suture spread and rotator cuff repairs. The knee is then brought into 30 degrees of extension for final fixation. Multiple options exist for suture fixation. The sutures can be tied over a bone branch, tied over a suture button, tied over a screw with a post or fixed with a knotless suture anchor. Here you can see final fixation with that crossed X in front of the anterior aspect of the fracture fragment, really nicely compressing that fracture fragment into the bony bed. Regardless of technique used, post-fixation fracture reduction should be assessed. Fracture stability with range of motion can also be assessed inter-articulately to determine the allowable early motion during physical therapy. Post-operative management includes early mobilization to avoid arthrofibrosis while enabling fracture healing. Early motion is limited to the range of motion assessed interoperatively, usually 30 to 40 degrees for the first two weeks. It can be as high as 90 degrees depending on fracture stability at the time of surgery. Protected weight bearing with the knee in extension is usually used for the first six weeks to protect your fixation construct. Late rehabilitation goals and milestones are similar to those after ACL reconstruction. Complications after tibial spine fracture fixation include arthrofibrosis most commonly, birth arrest uncommonly, loss of extension, and persistent ACL laxity. Functional instability is uncommon, but there is a significant rate of subsequent ACL reconstruction in 15 to 25% of patients. A study by Vanderhaef et al. showed that arthrofibrosis or stiffness can occur in 10% of patients. And this was defined as lacking 10 degrees of extension or having less than 90 degrees of flexion at three months. Arthrofibrosis was more severe in patients who underwent open fixation as opposed to arthroscopic fixation. Three of eight patients who were treated with only a manipulation under anesthesia and not a license of adhesions at the time of treatment of arthrofibrosis unfortunately suffered a distal femoral fracture, all of which resulted in distal femoral fascial arrest. So if your patient develops arthrofibrosis, the recommendation is to perform a license of adhesions with a gentle manipulation under anesthesia with post manipulation x-rays to confirm no fracture. So some takeaway points are non-op treatment for type one fractures, although some with incommon injury might need treatment and therefore you would fix the fracture at the time of treatment. This highlights the importance of a preoperative MRI. Operative treatment for all type two, three and four fractures. Screw fixation can be used if the fracture is large enough, suture fixation if the fracture is comminuted or you would like to tension the ACL if there's significant stretch injury seen on the preoperative MRI and a goal to avoid a second surgery for removal of hardware. Regardless of fixation technique, early post-op mobilization to avoid arthrofibrosis is essential. Thank you so much.

tibial spine injuries

management

avulsion fractures

non-operative treatment

operative treatment