BMC Musculoskeletal Disorders 2002, 3Case reportLigamentous rupture of the ACL associated with dislocated fracture of the proximal tibial physis in a 12-year-old boyStefan Scholz 1, Julian Köpke 2 and Lucas M Wessel *3
Address: 1Department of Surgery, Vanderbilt University Medical Center, Nashville/TN, USA, 2Institut für klinische Radiologie, Unversitätsklinik Mannheim, Germany and 3Kinderchirurgische Unversitätsklinik Mannheim/Heidelberg, Germany
AbstractBackground: Dislocated fracture of the proximal physeal plate of the tibia with or withoutmetaphyseal fragment is rare in children. This unusual fracture classically excludes rupture of theanterior cruciate ligament due to the ligament's stability. A combination of both injuries has notbeen previously published in the literature.
Case presentation: The authors report the case of a 12-year-old boy who presented with adislocated fracture (Salter-Harris II) of the proximal tibia combined with ligamentous rupture ofthe anterior cruciate ligament after a sporting accident.
BackgroundIn childhood, ligamentous injuries of the cruciate liga-ment or dislocated fractures of the proximal physeal plateof the tibia are rare occurrences. The combination of bothinjuries is not described in the literature due to differentmechanisms of injury and the stability of the ligament.We report the case of a boy with open physeal plates whopresented with a combination of both injuries after an ac-cident at a sporting event. No similar case has been previ-ously published.
Case presentationA 12-year old corpulent boy presented to the emergencyroom of our clinic after trauma to the right knee. Whenasked about the mechanism of injury, he stated that twofellow players had fallen on his right leg at a handballgame. His chief complaints were severe pain and tender-ness around the proximal tibia. On examination, an effu-sion of the knee joint with substantial extraarticular
swelling was noted. It was impossible to perform the ap-propriate function tests at the time of presentation sec-ondary to swelling and pain at the joint. Therefore, noligamentous injuries were detected on exam. Initial radio-graphs in three planes showed a slightly dislocated epiph-ysis of the proximal tibia with a metaphyseal fragment(Salter-Harris II), but no other osseous findings (Figures 1and 2). The direction of the dislocation was anterior andlateral. Standard blood works was unremarkable. A hor-monal disorder was not suspected because his history re-vealed a normal childhood development along the 97th
percentile with overweight running in his family. Physicalexam showed a genital development appropriate for hisage. Subsequently, the boy was taken to the operatingroom to reduce the fracture under general anesthesia. In-traoperative films demonstrated restoration of accurateanatomic alignment of the bony fragments (Figures 3 and4).
Published: 5 February 2002
BMC Musculoskeletal Disorders 2002, 3:5
Received: 7 September 2001Accepted: 5 February 2002
This article is available from: http://www.biomedcentral.com/1471-2474/3/5
Postoperatively, the right leg was immobilized with anopen cast. To exclude further intraarticular damage and todetermine potential damage to the growth plate that maypreclude future leg-length discrepancy, magnetic reso-nance imaging (MRI) of the right knee joint was per-formed the next day. At this time, the evaluating physiciandid not note additional intraarticular injuries, specificallyto the menisci and the cruciate ligaments. By postopera-tive day 7, the majority of the swelling of the knee jointhad decreased sufficiently with conservative measures toallow application of a closed cast. The patient was thenmobilized on crutches.
At the first scheduled follow-up visit 4 weeks post trauma,the cast was removed and the knee examined. Movementof the joint was painful with passive extension. A minorjoint effusion was still present. Meticulous testing of liga-
ment instabilities was impossible to perform due to thepatient's ongoing pain. MRI- and radiographic pictures intwo planes showed no increased postreduction displace-ment and regular anatomical alignment of the fracture(Figures 5 and 6). All intraarticular ligaments and the me-nisci were interpreted to be intact on the MRI-films. Con-sequently, the boy was allowed to weight bear astolerated.
At the next outpatient visit four weeks later, a thoroughphysical examination of the right leg revealed an atrophicquadriceps muscle and a positive anterior drawer in com-parison to the left side. Retrospective review of the previ-ous MRI-films by an experienced colleague clearlydepicted a previously missed rupture of the anterior cruci-ate ligament (ACL) with an enhanced signal of the tibialremainders of the ligament (Figure 7 and 8). Additionally,a pathologic signal along the tibial physeal plate was sus-picious for the beginnings of a bony bridge. Upon ques-tioning, the patient admitted that he had never been able
Figure 1The initial radiograph (lateral view) shows a slightly dislo-cated epiphysis of the proximal tibia with a metaphyseal frag-ment (Salter-Harris II).
Figure 2The initial radiograph (anterio-posterior view) reveals anopened physeal plate (medial) and a small metaphyseal frac-ture.
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to walk without pain on the injured leg since the cast wasremoved. As a result he had avoided regular activities andsports. Physical rehabilitation to compensate the joint in-stability by muscular means was initiated.
Two months later, the atrophy of the right quadriceps de-crease and the size of the right quadriceps was equalisedto the left. The patient was able to participate in light sportactivities without pain or instability. At examination, theright knee joint still demonstrated a positive anteriordrawer but no effusion or additional ligamentous insta-bility. Repeated MRI films showed a small bony bridge atthe lateral physis, but no alignment changes. The missing
anterior cruciate ligament was confirmed by the MRI-study.
Eleven months after the trauma, complete healing of thefracture with correct alignment was confirmed (Figures 9and 10). A leg-length discrepancy of 15 mm in favor of theinjured right leg was found on the radiographs but did notincrease over the following year. At the last office visitabout 30 months post injury, a minimal anterior drawerwithout further ligament instability or muscle atrophy
Figure 3Intraoperative fluoroscopy after reduction (lateral view).
Figure 4Intraoperative fluoroscopy after reduction (anterior-poste-rior view).
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was noted. The boy was not restricted in his regular activ-ities and was able to play team handball again.
ConclusionsFractures in skeletally immature patients behave different-ly than those in adults. One major reason for this phe-nomenon is the physeal plate which functions as the weaklink in the integrity of a growing skeleton when subjectedto trauma. When a joint with open physis is traumatized,the energy is dissipated by fracturing through the physis.The ligaments, capsule and bone are spared. It has beenaccepted that fractures involving the tibial growth plate ofthe knee preclude associated ligament damage.
Overall, fractures of the proximal tibial physeal plate arerare with a reported incidence of 0.2% of all pediatric frac-tures [1]. A literature review reveals no reports of fractureof the proximal tibial physis combined with rupture of the
anterior cruciate ligament. Most publications dealing withthis fracture fail to mention ligamentous integrity of theknee. Only Bertin and Goble [2] found laxity of the ante-rior cruciate ligament in four of thirteen adolescents intheir review of ligament injuries associated with physealplate fractures of the tibia. However, the authors did notreport one single ruptured cruciate ligament. In this series,MRI or arthroscopy was not applied. All injuries werecaused by high-energy trauma (motorcycle).
In the presented case, the dislocated Salter-Harris II frac-ture was accompanied by rupture of the anterior cruciateligament. The diagnosis was documented by physical ex-amination and repeated MRI. Clinical examination direct-ly after trauma was impossible due to pain, effusion andswelling of the knee. The accuracy of immediate examina-tion of stability under anesthesia is very reliable [3]. But,this important examination was not done because the at-tention was directed to the initial reduction without con-
Figure 5Four weeks after the accident: the radiograph shows goodalignment (lateral view).
Figure 6Four weeks after the accident: the radiograph shows goodalignment and callus (antero-posterior view).
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sideration of the intraarticular effusion and possibleligament damage. Also, mobility due to the fracture itselfcan simulate a positive anterior drawer. These may be rea-sons that this combination of injuries has never been re-ported previously. Associated anterior cruciate ligamenttears might have been initially overlooked.
As the potential mechanism of injury the authors suggestthat the dislocation of the tibial growth plate, which isone of the two largest and sturdiest of the human body,was too minimal to consume the energy of the traumacompletely. Subsequently, the remaining energy was di-rected to the anterior cruciate ligament and finally deplet-ed by its rupture.
Recent publications [4,5] have shown that the ability ofMRI to predict pediatric intraarticular knee pathology iscomparable to that in adults with an overall sensitivity
and specificity of 95% and 88%, respectively. Those num-bers correspond to our experience with arthroscopicallycontrolled intraarticular damage of the knee joint whichwas detected by MRI with adequate planes before [6]. Therepeated MRI-pictures combined with the clinical findingsconfirm the ruptured anterior cruciate ligament in the pre-sented case. However, the initial MRI early after traumamay miss a ligamentous injury, as demonstrated in thiscase.
The leg-length discrepancy of 15 mm, which was seen inthe follow-up radiographs after one year, must be calledidiopathic. Differences in the length of the legs are com-monly detected accidentally at the time of an injury. Idio-pathic leg-length differences exist in 25 to 75% and varybetween 5 and 30 mm [7]. As recommended by most au-thors [8], the patient was treated with physical rehabilita-tion and close follow-up to monitor functional instabilityand growth discrepancies.
Figure 7Four weeks after the accident: the MRI shows an intact pos-terior cruciate ligament (hypodense).
Figure 8Four weeks after the accident: no anterior cruciate ligamentcan be detected. The MRI shows an enhanced signal of thetibial remainders of the ligament.
Figure 9Lateral radiograph after 1 year.
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ate ligament tears: MR imaging-based diagnosis in a pediat-ric population. Radiology 1999, 213:697-704
5. McDermott MJ, Bathgate B, Gillingham BL, Hennrikus WL: Correla-tion of MRI and arthroscopic diagnosis of knee pathology inchildren and adolescents. J Pediatr Orthop 1998, 18:675-678
6. Wessel LM, Scholz S, Rüsch M, Köpke J, Loff S, Duchêne W, WaagKL: Hemarthrosis after trauma to the pediatric knee joint:what is the value of MRI in the diagnostic algorithm ? J PediatrOrthop, 2001, 21:338-342
7. von Laer L: Frakturen und Luxationen im Wachstumsalter, 199611-248. Fehnel DJ, Johnson R: Anterior cruciate injuries in the skeletally
immature athlete: a review of treatment outcomes. SportsMed 2000, 29:51-63
Figure 10Anterior-posterior radiograph after 1 year. Publish with BioMed Central and every
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