Eva M. Escobedo 1 William J. Mills 2 John. Hunter 1 Received July 10, 2001; accepted after revision October 1, 2001. 1 Department of Radiology, University of Washington Harborview Medical enter, 325 Ninth ve., Seattle, W 98104-2499. ddress correspondence to E. M. Escobedo. 2 Department of Orthopaedics, University of Washington Harborview Medical enter, Seattle, W 98104-2499. JR 2002;178:979 983 0361 803X/02/1784 979 merican Roentgen Ray Society Original Report The Reverse Segond Fracture: ssociation with a Tear of the Posterior ruciate Ligament and Medial Meniscus OJETIVE. We describe three patients who presented with radiographic findings of a fragment on the medial side of the tibial plateau of the knee that represented an avulsion of the deep portion of the medial collateral ligament. These findings were all associated with disruption of the posterior cruciate ligament and a peripheral medial meniscal tear the socalled reverse Segond fracture. ONLUSION. vulsion fracture at the tibial insertion of the deep component of the medial collateral ligament is a rare finding. When this type of injury is diagnosed, the radiologist should consider posterior cruciate ligament injury and peripheral medial meniscal tears as possible associated findings. T he Segond fracture is an avulsion of the lateral capsular ligament, which manifests as an elliptic bony fragment off the lateral proximal tibia, that has a high association with tear of the anterior cruciate ligament [1 3]. We describe three cases of a similar fragment on the opposite medial aspect of the proximal tibia representing an avulsion of the deep capsular component of the medial collateral ligament. ll three patients sustained injury (two avulsions and one tear) to the posterior cruciate ligament and a peripheral tear of the medial meniscus. To our knowledge, there has been only one report in the literature of a cortical avulsion adjacent to the medial tibial plateau. This injury, termed the medial or reverse Segond fracture, was reported to be associated with disruption of the posterior cruciate ligament and with medial meniscal tear [4]. Materials and Methods We retrospectively reviewed the medical records and imaging studies of three patients in whom a bony avulsion at the medial articular margin of the tibial plateau on radiographs of the knee was found. Two of these patients presented to the emergency department within 1 day of each other after pedestrian-versus-automobile collisions. The third was referred to our institution s orthopedic surgery clinic from an outside institution 6 months after being involved in a motor vehicle collision. Two patients were women and one was a man. The average age of the three patients was 39 years (age range, 29 52 years). ll patients underwent radiography, two underwent MR imaging, and one underwent T of the knee within 3 days of injury. ll underwent surgery of the knee: two, within 3 days of injury; and one, 6 months after injury. Results 29-year-old man, a 36-year-old woman, and a 52-year-old woman all sustained highenergy trauma to the knee. The man was struck by a van while he was crossing the street. The younger woman was struck by a vehicle while she was jogging. y report, she sustained a knee dislocation, which spontaneously reduced before she arrived in the emergency department. The older woman was ejected from an automobile after a motor vehicle collision, sustaining a knee dislocation and lateral dislocation of the patella. JR:178, pril 2002 979
Escobedo et al. Fig. 1. 29-year-old man involved in pedestrian-versus-automobile collision. and, nteroposterior () and close-up anteroposterior () radiographs of knee show small avulsion fragment (white arrow) off medial aspect of tibial plateau. one fragment adjacent to tibial eminence represents posterior cruciate ligament avulsion (black arrow)., oronal reformation of T scan shows deep medial collateral ligament avulsion fragment (white arrow) and resultant cortical defect (black arrow). D, Sagittal reformation of T scan shows avulsion fracture fragments (black arrows) of proximal attachment of posterior cruciate ligament. More superior fragment remains attached to posterior cruciate ligament (white arrows). Physical examination of both the man and the younger woman revealed ligamentous laxity, but both examinations were difficult to perform because both patients were in pain, had swelling, and had other injuries. Examinations performed with the patient under anesthesia revealed gross medial collateral and posterior cruciate ligament laxity in both of these patients. The woman also had anterior cruciate ligament laxity. The 52-year-old woman presented to the emergency department with a dislocated knee. Her knee dislocation was reduced at arrival to the emergency department, and external fixation of the knee was performed to maintain re- 980 D duction. She presented 6 months after injury to our institution s orthopedic surgery clinic. In all three patients, anteroposterior radiographs of the knee showed a bone fragment at the medial aspect of the tibial plateau just distal to the articular surface (Figs. 1, 1, 2, 2, and 3). bony fragment adjacent to the tibial eminence in the knee of the 29-year-old (Fig. 1) was also present. For the 52-year-old woman, who had returned to the clinic 6 months after injury, a follow-up radiograph of the knee was obtained and showed the medial tibial avulsion fragment, which appeared well corticated (Fig. 3). T scan was obtained in the 29-year-old patient. This scan showed an avulsion fragment off the medial rim of the tibial plateau (Fig. 1) and bony fragments off the site of the femoral attachment of the posterior cruciate ligament (Fig. 1D), one of which corresponded to the fragment seen adjacent to the tibial eminence on radiograph of the knee (Fig. 1). minimally depressed fracture of the lateral tibial plateau (not shown) was also found in this patient. MR imaging of the knee was performed in the other two patients. In the 36-year-old woman, MR images showed severe disruption of the medial collateral ligament (Fig. 2). JR:178, pril 2002
Imaging of the Reverse Segond Fracture Fig. 2. 36-year-old woman involved in pedestrian-versus-automobile collision. and, nteroposterior () and close-up of anteroposterior () radiographs of knee shows small avulsion fragment (arrow) off medial aspect of tibial plateau., Proton density weighted fast spin-echo coronal MR image of knee shows bony avulsion (arrowhead) of deep medial collateral ligament with cortical defect (small arrow). Large arrow shows peripheral tear of medial meniscus. D, T2-weighted fat-suppressed fast spin-echo sagittal MR image of knee shows avulsion (arrow) of proximal posterior cruciate ligament. The medial tibial fragment seen on radiographs was noted retrospectively, as were both a small adjacent cortical defect and a peripheral tear of the medial meniscus (Fig. 2). vulsion of the posterior cruciate ligament at the femoral insertion (Fig. 2D) and avulsion of the anterior cruciate ligament at the tibial insertion (not shown) were also noted. Imaging (not shown) also revealed a small focal fracture of the rim of the lateral tibial plateau. In the 52-year-old woman, MR imaging showed complete disruption of the superficial and deep medial collateral ligament and a tear of the posterior cruciate ligament (Fig. 3). Evaluation was otherwise limited because of severe subluxation and rotation of the unstable knee. JR:178, pril 2002 In all three patients, surgery revealed avulsion of the deep medial collateral ligament from the tibia and either a tear or an avulsion of the superficial medial collateral ligament; moreover, a peripheral medial meniscal avulsion from the deep medial collateral ligament was also detected. Healing of this injury was seen in the patient who had surgery 6 months after injury. Two patients had an avulsion of the posterior cruciate ligament from its femoral origin. One had a tear of the midsubstance of the posterior cruciate ligament. The lateral ligaments were intact in all patients. In addition to these injuries, the 36-year-old woman had an avulsion of the anterior cruciate ligament from its tibial insertion. D The 36-year-old woman sustained a concomitant injury to the opposite knee; at surgery, tears of the anterior cruciate ligament, lateral capsule, lateral collateral ligament, biceps tendon, and popliteal fibular ligament were found. These injuries were consistent with a varus and internal rotation mechanism presumably opposite that of the right knee. Discussion In all three patients, the medial avulsion seen on radiographs corresponded to an avulsion of the tibial attachment of the deep medial collateral capsular ligament. Other than in one previous case report by Hall and 981
Escobedo et al. Fig. 3. 52-year-old woman involved in high-energy motor vehicle collision., nteroposterior intraoperative fluoroscopic spot film of knee shows small avulsion fragment (arrow) adjacent to medial joint line and evidence of cortical disruption (arrowhead) of medial tibia., Proton density weighted fast spinecho sagittal MR image shows disruption of posterior cruciate ligament. Note coronal position of tibia that results from significant ligamentous instability. Distal end of posterior cruciate ligament (long white arrow) is intact, but entire proximal portion (short white arrows) is disrupted. Disruption (black arrows) of superficial medial collateral ligament is shown. Deep medial collateral ligament (arrowhead) is also torn., nteroposterior radiograph of knee 6 months after trauma shows avulsion fragment (white arrow), now well corticated. lack arrow shows medial tibial bony defect. Hochman [4], we are not aware of other reports in the literature describing this finding. Our three patients and the patient previously reported all had disruption of the posterior cruciate ligament: two midsubstance tears and two femoral avulsions. ecause of the disruption of the medial collateral ligament, the presumed mechanism of injury for all three patients is valgus stress, with probable external rotation. Two of our patients had minimally depressed lateral tibial plateau fractures. In addition, neither lateral instability on examination nor lateral capsular injury at surgery was noted in either patient. These findings further support a valgus mechanism of injury. lthough we found no lateral 982 ligamentous injuries, other concomitant injuries such as the anterior cruciate ligament tear in one patient are not surprising considering the often complicated nature of these high-energy injuries. Two patients (the previously reported case [4] and one of our cases) presumably underwent valgus stress in one knee with varus stress in the opposite knee. This mechanism, producing a tear of the medial capsule (deep medial collateral ligament) and disruption of the posterior cruciate ligament, appears to be the opposite mechanism of the Segond fracture that is, valgus and external rotation versus varus and internal rotation. In fact, in these two patients, a Segond fracture of the opposite knee was noted in the former, and a Segondlike injury of the opposite knee with a tear of the lateral capsule and anterior cruciate ligament (among other injuries) was seen in the latter. ecause little about avulsion fractures off the medial tibia has been mentioned in the literature, we are presuming that this finding is rare. Two of our cases and the previously reported case [4] were all a result of motor vehicle versus-pedestrian collisions. Two of our patients sustained knee dislocations. Perhaps this high-speed direct blow involves a unique mechanism not seen with the more common sports injuries. Even in the absence of the finding of an associated disruption of the posterior cruciate ligament, this avulsion injury is an im- JR:178, pril 2002
Imaging of the Reverse Segond Fracture portant radiographic finding because it indicates severe injury to both superficial and deep portions of the medial collateral ligament. The three patients we have described were all involved in high-energy trauma. One presented with a dislocation; one had a reported dislocation; and one had a grossly unstable knee with multiligamentous instability, or a dislocatable knee. The concept that the dislocatable knee has a similar clinical significance and complications (i.e., vascular and nerve injury) as a recognized dislocation was emphasized by Twaddle et al. [5]. lthough we are uncertain whether the reverse Segond fracture is always associated with a dislocated or dislocatable knee, we can say that at least in our limited number of cases there was a high association with multiligamentous instability that may imply dislocation. Therefore, just as the presence of a Segond fracture on radiography is an indication of significant internal derangement, the presence of the reverse Segond fracture could be the only indication of an unrecognized dislocation. Such suspicion should alert both the radiologist and clinician to a potential dislocation so that appropriate physical examination and, if needed, vascular imaging can be performed in a timely manner. The cases presented here as well as the case described by Hall and Hochman [4] show that a consistent triad of posterior cruciate ligament, medial collateral ligament, and medial meniscal injuries is suggested by the radiographic finding of the reverse Segond fracture. We believe this finding has not only diagnostic significance but also clinical significance. Physical examination of our patients revealed gross valgus knee laxity without an appreciable end point, which is consistent with a grade IV medial collateral ligament tear. t surgery, these findings were confirmed by the fact that both the deep and superficial layers of the medial collateral ligament were completely disrupted. Of equal importance was the essentially complete separation of the medial meniscus from its deep medial collateral ligament capsular margin. This injury was present in all three of our patients. Hall and Hochman reported that a medial meniscus tear was present in their patient, but the exact type of tear was not mentioned. lthough we routinely address high-energy medial collateral ligament injuries with grade IV laxity surgically, this treatment is not necessarily a common practice. Recently other researchers have recommended surgical repair of the medial collateral ligament injury when it occurs in conjunction with an anterior cruciate ligament tear [6]; this recommendation deviates from the previously accepted treatment of patients with closed management of the medial collateral ligament and surgical treatment of the anterior cruciate ligament injury [7]. lthough few reports in the literature detail the treatment of combined posterior cruciate and medial collateral ligament injury, many clinicians would likely manage both tears closed. However, the high-grade nature of the medial collateral ligament injury and the complete separation of the medial meniscus from the capsule represented by the reverse Segond fracture suggest that surgical intervention would be necessary to restore the anatomy of these medial structures. In the future, we will anticipate this injury triad when a patient with a valgus-loading injury presents with this unusual radiographic finding. In conclusion, the radiographic finding of a small bone fragment adjacent to the medial tibial plateau represents an avulsion of the deep medial collateral ligament. It is associated with significant injury to the medial collateral ligament and may be associated with significant internal derangement, including disruption of the posterior cruciate ligament and a peripheral medial meniscal tear. References 1. Dietz G, Wilcox D, Montgomery J. Segond tibial condyle fracture: lateral capsular ligament avulsion. Radiology 1986;159:467 469 2. Woods G, Stanley R, Tullos H. Lateral capsular sign: x-ray clue to a significant knee instability. m J Sports Med 1979;7:27 33 3. Goldman, Pavlov H, Rubenstein D. The Segond fracture of the proximal tibia: a small avulsion that reflects major ligamentous damage. JR 1988;151:1163 1167 4. Hall F, Hochman M. Medial Segond-type fracture: cortical avulsion off the medial tibial plateau associated with tears of the posterior cruciate ligament and medial meniscus. Skeletal Radiol 1997;26:553 555 5. Twaddle, Hunter J, hapman J, Simonian P, Escobedo E. MRI in acute knee dislocation: a prospective study of clinical, MRI, and surgical findings. J one Joint Surg r 1996;78:573 579 6. Frolke J, Oskam J, Vierhout P. Primary reconstruction of the medial collateral ligament in combined injury of the medial collateral and anterior cruciate ligaments: short-term results. Knee Surg Sports Traumatol rthrosc 1998;6:103 106 7. allmer P, allmer F, Jakob R. Reconstruction of the anterior cruciate ligament alone in the treatment of combined instability with complete rupture of the medial collateral ligament: a prospective study. rch Orthop Trauma Surg 1991;110: 139 141 JR:178, pril 2002 983