Postoperative MDCT of Tibial Plateau Fractures

Musculoskeletal Imaging Original Research Mustonen et al. Postoperative MDCT of Tibial Plateau Fractures Musculoskeletal Imaging Original Research ntti O. T. Mustonen 1 Mika P. Koivikko 1 Martti J. Kiuru 2 Jari Salo 3 Seppo K. Koskinen 1 Mustonen OT, Koivikko MP, Kiuru MJ, Salo J, Koskinen SK Keywords: knee, MDCT, postoperative, tibial plateau fracture DOI:10.2214/JR.08.2260 Received December 16, 2008; accepted after revision pril 15, 2009. 1 Department of Radiology, Helsinki Medical Imaging Center, Helsinki University Central Hospital, Töölö Trauma Center, Topeliuksenkatu 5, FIN 00029, Helsinki, Finland. ddress correspondence to. O. T. Mustonen (antti.mustonen@helsinki.fi). 2 Suomen Terveystalo, Helsinki, Finland. 3 Department of Orthopedics and Traumatology, Helsinki University Central Hospital, Töölö Trauma Center, Helsinki, Finland. JR 2009; 193:1354 1360 0361 803X/09/1935 1354 merican Roentgen Ray Society Postoperative MDCT of Tibial Plateau Fractures OJECTIVE. The purposes of this retrospective study were to elaborate our experience in postoperative MDCT of tibial plateau fractures, to establish the frequency of these fractures and the indications for MDCT, and to assess the common findings and their clinical importance. MTERILS ND METHODS. total of 782 knee injuries were imaged with MDCT at a level 1 trauma center over 86 months. total of 592 knees had a tibial plateau fracture; 381 of these fractures were managed surgically, and postoperative MDCT was performed on 36 of these knees (9%). t postoperative image analysis, an orthopedic surgeon evaluated reduction as good or suboptimal using the first postoperative radiographs. Fracture healing was determined as complete ossification, partial ossification, or nonunion on MDCT images acquired later in follow-up. The MDCT findings were compared with the radiographic findings to assess the usefulness and clinical importance of MDCT. RESULTS. The main indications for MDCT were assessment and follow-up of the joint articular surface and evaluation of fracture healing. Orthopedic hardware caused no diagnostic problems at MDCT. Postoperative MDCT revealed additional clinically important information on 29 patients (81%), and 14 patients (39%) underwent reoperation. CONCLUSION. Postoperative MDCT of tibial plateau fractures is performed infrequently, even in a large trauma center. When it is performed, however, because of suspicion of increasing articular step-off or fracture nonunion, postoperative MDCT reveals clinically significant information in most cases. cute tibial plateau fracture, a common knee trauma [1 3], usually necessitates surgical treatment and subsequent, often prolonged follow-up [4 6]. MDCT is a powerful imaging method for both primary diagnostics and preoperative planning in the care of patients with these challenging injuries, allowing exact assessment of the complex fracture pattern [2]. Postoperative and follow-up imaging of tibial plateau fractures is performed predominantly with conventional radiography. MDCT, however, has been used successfully in postoperative imaging of other joints, such as the ankle and shoulder [7 9]. t our institution, an increasing amount of follow-up imaging of surgically managed tibial plateau fractures involves MDCT, either to ensure the postoperative result in complex fractures or, in the later phase, to ensure that bone healing will allow increased weight-bearing. To our knowledge, no studies have been conducted to explore these issues in the surgical management of tibial plateau fractures. The purpose of this study was to elaborate our experience in postoperative MDCT of tibial plateau fractures, particularly to establish the frequency of and indications for such examinations and to assess the common findings and their clinical importance. Materials and Methods This retrospective study was conducted at a level 1 trauma center in a region of almost 1.5 million people. The study was approved by the hospital ethics committee. Patient Selection Using the hospital PCS, we retrieved all emergency department records of 782 patients who underwent MDCT for knee trauma over the 86-month period of January 2001 March 2008. Indications for primary diagnostic MDCT were to exclude fracture and to visualize the morphologic features of fractures for preoperative planning. total of 592 patients had an acute tibial plateau fracture detected in the acute phase (within 1 week; mean, within 24 hours). Of these, 381 pa- 1354 JR:193, November 2009

Postoperative MDCT of Tibial Plateau Fractures tients (64%) underwent surgery; 36 of the 381 patients (9%) also underwent postoperative MDCT and comprised the study group. Patient charts were used for verification of the clinical history. Only the injured knee was studied. Image nalysis The images were evaluated with clinical PCS workstations (Impax DS3000 version 4.5, gfa- Gevaert) by the same radiologist and orthopedic surgeon. ware of the clinical history, they reviewed MDCT images and reached a consensus. MDCT Protocol Each patient underwent knee MDCT with a 4-MDCT scanner (LightSpeed QX/i, GE Healthcare). The routine protocol was: collimation, 4 1.25 mm; interval, 0.62 mm; gantry rotation time, 1.0 second; pitch, 3; table feed, 3.75 mm; 120 kv; 150 m; approximate total exposure time, 10 15 seconds. Routine MDCT scanning ranged from the upper pole of the patella to a position caudal to the fibular head and included routine multiplanar reconstructions in standard sagittal and coronal planes at a slice thickness of 2.0 mm and reconstruction increment of 2.0 mm. Classification of Tibial Plateau Fractures at MDCT Tibial plateau fractures were assessed according to the rbeitsgemeinschaft für Osteosynthesefragen/Orthopedic Trauma ssociation (O/ OT) classification [10]. ll fractures were classified type or C and group 1, 2, or 3. These fractures were not further divided into subgroups, because such subgroups are not routinely used at our institution. Type fractures, not specific to medial or lateral plateau, involve one condyle: 1 is a pure split fracture; 2, a pure depression fracture; 3, a split-depression fracture. Type C fractures involve both condyles: C1 is a metaphyseal simple fracture; C2, a metaphyseal multifragment fracture; C3, a multifragment articular fracture. Tibial plateau fractures also were assessed according to the Schatzker classification [11]. Schatzker I is a lateral split fracture; II, a split fracture with articular surface depression; III, a pure lateral articular surface depression; IV, a pure medial articular surface depression; V, a bicondylar fracture; and VI, a split fracture that extends to the metadiaphysis. The maximal depression of the tibial articular surface also was measured. Postoperative Image nalysis Using the first postoperative radiographs, the orthopedic surgeon retrospectively assessed reduction as good or suboptimal. Reduction was considered good if it was anatomic or if only minor (< 3 mm) articular step-off was evident. Reduction was considered suboptimal if diastasis or articular step-off of 3 mm or more was evident. t our institution, articular step-off of more than 5 mm has served as a general guideline for immediate reoperation. MDCT images were used to determine whether fracture healing was complete ossification, partial ossification, or nonunion in the later phase. fracture was judged completely ossified when indisputable dense cortical bridging facing the cortical bones was detectable in continuous axial slices in both the anterior and posterior cortexes or when dense continuous endosteal callus formation was evident. fracture was judged partly ossified when dense cortical bridging was evident in one cortex only or clear endosteal callus formation was evident but was not visible in indisputable continuity. fracture was judged nonunion (pseudoarthrosis) when no dense cortical bridging was evident and the presence of a clear lucent cleft between rounded bone edges was determined. The maximal depression of the tibial articular surface was measured on MDCT images, and image quality deterioration caused by orthopedic hardware was evaluated. Finally, to assess the usefulness and clinical importance of MDCT, the MDCT findings were compared with those on contemporaneous radiographs. Results Clinical History and Preoperative MDCT Findings The final study group, of the original 381, comprised 36 patients (9%) (24 men, 12 women; mean age, 47 years; range, 15 79 years). Injury mechanisms were traffic accident for 16 patients, simple fall for 13, sports injury for four, and fall from a height for three. The tibia plateau fractures were of all types (Table 1). The average articular depression of the tibial plateau was 9.4 mm (range, 0 36 mm). Surgery and Results of Immediate Postoperative Imaging ll patients underwent open surgery; three patients underwent intraoperative arthroscopic evaluation of joint surfaces. Medial plates were used for fixation of the fractures in three patients, lateral plates in 13, and both medial and lateral plates in three patients. Eight patients needed contralateral or ipsilateral screw fixation with plates, and nine needed only screw fixation. To fill intraosseous defects, an autologous cancellous bone graft from the iliac crest was used in 25 patients and bone cement in two. Using the immediately postoperative radiographs, the orthopedic surgeon retrospectively judged reduction as good in 25 patients and suboptimal in 11 patients. TLE 1: Distribution of Tibial Plateau Fractures Classification System No. of No. of Fractures Reoperations rbeitsgemeinschaft für Osteosynthesefragen/ Orthopedic Trauma ssociation 1 1 1 2 9 3 12 6 C1 1 1 C2 5 1 C3 8 5 Total 36 14 Schatzker I 1 II 7 4 III 7 IV 7 2 V 8 4 VI 6 4 Total 36 14 Note Dash [ ] indicates no fracture in class. Timing and Indications for Postoperative MDCT Postoperative MDCT was performed a mean of 131 days (range, 2 396 days) after surgery. In 11 patients (30%), MDCT was performed in the immediate postoperative period (within 14 days; mean, 6). For those patients, reduction was assessed as suboptimal after the first postoperative radiographs, and the indication for MDCT was evaluation of congruency of the tibial articular surface (Fig. 1). The other 25 patients underwent MDCT during follow-up. The indications for MDCT were evaluation of the radiographic finding of suspected worsening of the articular depression for seven patients and assessment of fracture ossification that was uncertain on radiographs for 18 patients (Figs. 2 and 3). Postoperative MDCT Findings Orthopedic hardware t MDCT, all 36 knees scanned contained orthopedic hardware: medial plates in three knees, lateral plates in 13, both types of plate in three, screws from screw-and-plate fixation in eight, and screws that had been used without plates in nine knees. ll patients had metallic artifacts; these artifacts slightly impaired assessment of fracture gaps in two patients and JR:193, November 2009 1355

Mustonen et al. Fig. 1 28-year-old woman with medial tibial plateau fracture (O/OT type 2, Schatzker III) due to sports injury. fter open surgical reduction and autologous cancellous bone graft from iliac crest, fracture was fixed with medial plate., nteroposterior radiograph shows immediate postoperative findings., Lateral radiograph obtained immediately postoperatively shows suspicious articular surface depression (arrow). C and D, Coronal (C) and sagittal (D) reformatted MDCT images obtained on same day as and show no articular surface depression. assessment of the joint surface in one patient but caused no actual diagnostic problems. rticular depression On all postoperative MDCT images, the average depression of the tibial plateau was 4.0 mm (range, 0 22 mm). The 11 patients who underwent MDCT in the immediate postoperative period (mean, 6 days) had an average surface depression of 8.5 mm (range, 0 22 mm; median, 5 mm). Three of these patients underwent reoperation with an average articular depression of 6.4 mm. mong the seven patients who underwent follow-up imaging for suspected worsening of the plateau fracture, an average depression of 15.1 mm (range, 0 36 mm) was detectable, and three of these patients underwent reoperation. Ossification For the 18 patients in whom ossification was not definitely confirmed on radiographs, MDCT was performed a mean of 237 days (range, 121 396 days) after surgery to determine the presence of ossification. Four of the patients had fracture union, five had partly ossified fractures, and nine had nonunion. In 14 of these patients, the bone density between the preoperative and postoperative MDCT examinations was noticeably less than that of the trabeculae of the distal femur and proximal tibia (Fig. 4). Clinical importance Compared with contemporaneous radiographs, MDCT scans contained additional clinically useful information, and thus MDCT was assessed as necessary in 29 cases (81%). In the other seven cases, MDCT did not yield additional radiologic information. The clinical indication for MDCT had been immediate postoperative imaging of the tibial joint surface in two of the seven cases, suspected deterioration of joint surface depression in two, and evaluation of fracture healing in three cases. fter postoperative MDCT, 14 patients (39%) underwent reoperation. Three of these patients underwent reoperation immediately after postoperative radiography and subsequent MDCT because of suboptimal reduction; three patients, because of depression of the articular surface during follow-up confirmed at MDCT; and eight patients, because of nonunion detected at MDCT. C Discussion Radiography is the cornerstone of knee fracture imaging and one of the most common radiologic examinations in trauma units, but MDCT is a powerful tool for both screening and assessment of the morphologic features of fractures, yielding markedly more information than does radiography [2]. Nevertheless, follow-up imaging is mostly by radiography [12]. MDCT is used postoperatively for more complicated injuries, in which radiographs may not reveal the morphologic condition of relevant bony structures because of the presence of orthopedic hardware or orthoses or difficulties in patient positioning. The increasing number of MDCT scanners means that MDCT may be used increasingly for postoperative imaging. Studies have shown that MDCT supplements postoperative evaluation of joints, providing further characterization or confirmation of suspected postoperative complications [7 9]. In the postoperative evaluation of patients with orthopedic hardware, the MDCT protocol must be optimized for artifact reduction. Image quality at D 1356 JR:193, November 2009

Postoperative MDCT of Tibial Plateau Fractures MDCT is affected by the composition and orientation of orthopedic hardware, acquisition parameters, and reconstruction parameters [8, 13, 14]. On modern scanners, protocols for overcoming these factors usually are readily available, and adjusting the parameters is easy for any radiologist who has at least general experience in MDCT. With correct adjustments, MDCT can be accurate in the assessment of bony structures, fracture healing, and postoperative complications, which are not always well visualized on radiographs of patients who have orthopedic hardware [7 9, 13, 14]. The radiation dose for examination of a peripheral joint such as the knee is negligible D E Fig. 2 69-year-old woman with tibial plateau fracture (O/OT type 3, Schatzker IV) due to traffic injury., Coronal reformatted preoperative MDCT shows tibial plateau fracture. and C, nteroposterior () and lateral (C) follow-up radiographs 8 months after surgery do not confirm complete ossification. D and E, Coronal (D) and sagittal (E) reformatted MDCT images obtained same day as and C confirm complete ossification. [15], and with newer-generation scanners, the dose is further decreasing [16]. We evaluated the frequency, findings, clinical importance, and indications for postoperative MDCT of tibial plateau fractures. To our knowledge, this subject has been previously unexplored. Whereas MDCT has become increasingly important in the primary diagnosis of knee trauma, for postoperative and follow-up imaging, MDCT continues to be a problemsolving tool used sparingly. Of 782 patients with knee injuries who underwent MDCT, 592 had a tibial plateau fracture; of those, 381 underwent surgery, and only 36 (9%) needed postoperative MDCT. When requested, however, postoperative MDCT in most cases did yield more clinically relevant information than did conventional radiography. Indisputably, this assessment of clinical relevance, although made in consensus with the orthopedic surgeon, is subjective and was a limitation of our study. Our study also was biased toward more complicated fractures, possibly making our results inapplicable to all surgically managed tibial plateau fractures. Our retrospective study design included the typical limitations of assessment of clinical importance. randomized prospective study would be ideal, perhaps measuring clinical outcome at various stages. With trauma C JR:193, November 2009 1357

Mustonen et al. Fig. 3 54-year-old woman with tibial plateau fracture (O/OT type C3, Schatzker V) due to traffic injury. fter reduction and autologous cancellous bone graft from iliac crest, fracture was fixed with lateral plate. and, nteroposterior () and lateral () follow-up radiographs 6 months after surgery show areas of suspected nonunion (arrowhead). C and D, Coronal reformatted (C) and axial (D) MDCT images obtained day after and confirm nonunion with only minute bridged callus (arrow, D) in posterior cortex. patients, however, such a prospective study is difficult. Moreover, limiting a randomized cohort of patients to radiography only to prevent selection bias would be unethical. Interestingly, in only three cases did metal artifacts impair image quality, and these artifacts caused no diagnostic difficulties. On the 4-MDCT scanner, orthopedic hardware posed no contraindication to MDCT, C and with the rapid evolution of MDCT, image quality is being constantly increased [12, 17]. t radiography, in contrast, orthopedic hardware, plates specifically, severely impairs the visibility of joint surfaces and of often obscure fracture lines. Unexpectedly, postoperative MDCT was not performed to evaluate suspected hardware loosening and infection. t our institution, angle-stable locking screw plates have been used in the management of tibial plateau fractures for almost 5 years, and this factor may explain the small amount of suspected hardware loosening. We have not yet performed MDCT for that indication. t our institution, the deeptissue infection rate is less than 0.2%, and the superficial-tissue infection rate is less than 2%. These low numbers may explain why no D Fig. 4 49-year-old man with tibial plateau fracture (O/OT type C3, Schatzker V) due to traffic injury., xial MDCT image of distal femur shows preoperative bone density., Six-month surgical follow-up axial MDCT image shows bone density decrease (osteoporosis) in distal femur and fractured tibia. 1358 JR:193, November 2009

Postoperative MDCT of Tibial Plateau Fractures patient with a surgically managed tibial plateau fracture with suspected deep infection underwent MDCT during this study. With our surgical deep-tissue infection rate of 0.2%, statistically 500 knees should be operated on to produce one with infection. Until March 2008, we consecutively imaged 381 postoperative knees with no suspected infections. Studies [18, 19] have shown that in detection of acute tibial plateau fractures, four views are more sensitive than two. This finding may also be true in postoperative follow-up, especially in evaluation of the articular surface. t immediate postoperative conventional radiography, however, patients may be in pain, and orthoses interfere with appropriate positioning, so time-consuming additional views are difficult or even impossible to obtain. MDCT is fast, and exact knee positioning is less crucial [8]. Thirty percent of our patients were imaged in the immediate postoperative period, when problems with appropriate radiographs in particular occurred. We therefore suggest performance of MDCT, especially immediately postoperatively. In later follow-up, four views may help in study of the articular surface, but in our experience, additional views do not necessarily improve the accuracy of assessment of the degree of fracture union. Therefore, at our institution, standard anteroposterior and lateral views are routinely chosen for followup of knee fractures, and additional views are deemed unnecessary. modern MDCT scanner can generate 2D reformats and 3D surface rendering of outstanding quality that help in the detection of complications in surgically treated patients with orthopedic hardware [8]. Newer-generation scanners generate isotropic voxels, and multiplanar reconstructions can be made in every plane without loss of spatial resolution [13], further increasing the benefits of MDCT in follow-up imaging. In addition, radiologists and orthopedic surgeons using workstations can obtain the optimal plane for viewing retrospectively, a clear benefit over radiography. t our institution, 3D images are often requested immediately preoperatively but seldom during follow-up, even in the case of reoperation. When requested to do so by orthopedists, radiologists make specific 3D images with workstations. We are training technicians to produce basic 3D images for all skeletal MDCT examinations. For one half of our patients, the indication for late postoperative MDCT was determination of fracture ossification, which is inconclusive on radiographs. For the others, the indication was suspected worsening of the articular surface depression beyond the potential of radiographs. Postoperative MDCT therefore is a powerful problem-solving weapon completing the diagnostic armory. mong our patients, 39% underwent reoperation after MDCT, further justifying the use of MDCT. In seven cases MDCT, in retrospect, did not reveal additional radiologic information compared with radiographs. Our chart review showed that some of those MDCT examinations, such as those requested by an orthopedic resident without first consulting a senior orthopedic surgeon or radiologist about radiography, might have been avoided with better knowledge of radiographic features and fracture patterns. ssessment of postoperative radiographs of tibial plateau fractures is, however, a task challenging to even experienced radiologists and orthopedic surgeons. Diagnostic errors and misinterpretations are inescapable in daily clinical practice. One should also bear in mind that in the care of patients with symptoms, MDCT can be used to evaluate possible additional findings that may explain the symptoms even if no suspected complications are evident on radiographs. However, MDCT sometimes is needed to confirm findings also evident, at least retrospectively, on radiographs. We can perhaps conclude that retrospective judgment on the relevance of MDCT cannot be based solely on radiographic findings. In patients undergoing MDCT more than 3 months after surgery, the bone density of the femur and tibia noticeably decreased. Osteoporosis due to immobilization of the limb and reduced weight-bearing may not alone explain this phenomenon. Locking screw plates, however, effectively remove weightbearing stress from the bone; this factor in part and in conjunction with increased bone turnover near the fracture may explain loss of density. Findlay et al. [20] found that in fractured tibias the greatest bone density decrease occurred in trabecula-rich bone at sites closest to the fracture. Theoretically, moreover, the increased vascularity and bone turnover of a fractured tibia also may account for this demineralization. lthough exact articular step-off is easy to measure after postoperative MDCT, the orthopedic surgeon s decision for reoperation is always at least partly subjective and cannot be based solely on imaging findings. t our institution, a 5-mm postoperative articular step-off usually is an indication for reoperation, but other factors, such as the patient s age, interests, and compliance must be taken into consideration. We are establishing new guidelines for postoperative use of MDCT of tibial plateau fractures. The first is that in the immediately postoperative phase, MDCT is not needed if the first postoperative radiographs show good reduction and orthopedic hardware does not obscure the articular surface. Second, evidence of marked malreduction on radiographs is an indication for MDCT to discern the exact morphologic features, hardware position, and position of bone fragments in relation to orthopedic hardware. In such cases, MDCT findings can aid orthopedic surgeons in decisions regarding reoperation, especially a decision not to reoperate although radiographs show suboptimal reduction. Third, in the later postoperative phase, MDCT is not needed if follow-up radiography shows no worsening decline of reduction and no increase in articular step-off. Fourth, for patients with symptoms, MDCT should be considered in order to exclude findings beyond the capability of radiography that explain the symptoms. Fifth, MDCT is recommended as a complementary examination if increasing articular surface depression, hardware failure, or nonunion is suspected on follow-up radiographs. We found that only a small number (9%) of our patients who undergo surgical management of tibial plateau fractures undergo MDCT after surgery or later during followup. The main indications are assessment and follow-up of the joint articular surface and evaluation of fracture healing. Image quality did not deteriorate because of the presence of orthopedic hardware, and MDCT depicted areas not visualized on radiographs. fter postoperative MDCT, 39% of patients underwent reoperation. Targeted MDCT yields relevant and detailed information beyond the capabilities of conventional radiography, markedly improving patient care and the final results of management of radiologically and surgically challenging tibial plateau fractures. References 1. Fagan DJ, Davies S. The clinical indications for plain radiography in acute knee trauma. Injury 2000; 31:723 727 2. Mustonen O, Koskinen SK, Kiuru MJ. cute knee trauma: analysis of multidetector computed tomography findings and comparison with conventional radiography. cta Radiol 2005; 46:866 874 JR:193, November 2009 1359

Mustonen et al. 3. Stiell IG, Wells G, Hoag RH, et al. Implementation of the Ottawa knee rule for the use of radiography in acute knee injuries. JM 1997; 278:2075 2079 4. Cetik O, Cift H, sik M. Second-look arthroscopy after arthroscopy-assisted treatment of tibial plateau fractures. Knee Surg Sports Traumatol rthrosc 2007; 15:747 752 5. Papagelopoulos PJ, Partsinevelos, Themistocleous GS, Mavrogenis F, Korres DS, Soucacos PN. Complications after tibia plateau fracture surgery. Injury 2006; 37:475 484 6. Toro-rbelaez J, Gardner MJ, Shindle MK, Cabas JM, Lorich DG, Helfet DL. Open reduction and internal fixation of intraarticular tibial plateau nonunions. Injury 2007; 38:378 383 7. estic JM, Peterson JJ, DeOrio JK, ancroft LW, erquist TH, Kransdorf MJ. Postoperative evaluation of the total ankle arthroplasty. JR 2008; 190:1112 1123 8. uckwalter K, Parr J, Choplin RH, Capello WN, Multichannel CT: imaging of orthopedic hardware and implants. Semin Musculoskelet Radiol FOR YOUR INFORMTION 2006; 10:86 97 9. Woertler K. Multimodality imaging of the postoperative shoulder. Eur Radiol 2007; 17:3038 3055 10. Muller ME, Nazarian S, Koch P, Schatzker J. The comprehensive classification of fractures of long bones. New York, NY: Springer-Verlag, 1990 11. Schatzker J. Fractures of the tibial plateau. In: Schatzker J, Tile M, eds. The rationale of operative fracture care, 2nd ed. erlin, Germany: Springer-Verlag, 1996:419 438 12. Vande erg, Malghem J, Maldague, Lecouvet F. Multi-detector CT imaging in the postoperative orthopedic patient with metal hardware. Eur J Radiol 2006; 60:470 479 13. Douglas-kinwande C, uckwalter K, Rydberg J, Rankin JL, Choplin RH. Multichannel CT: evaluating the spine in postoperative patients with orthopedic hardware. RadioGraphics 2006; 26[suppl 1]:S97 S110 14. Lee MJ, Kim S, Lee S, et al. Overcoming artifacts from metallic orthopedic implants at highfield-strength MR imaging and multi-detector CT. RadioGraphics 2007; 27:791 803 15. Nagel HD. Dose values from CT examinations. In: Nagel HD, ed. Radiation exposure in computed tomography. Hamburg, Germany: CT Publications, 2002:15 24 16. Henckel J, Richards R, Lozhkin K, et al. Very low-dose computed tomography for planning and outcome measurement in knee replacement: the imperial knee protocol. J one Joint Surg r 2006; 88:1513 1518 17. Ohashi K, El-Khoury GY, ennett DL, Restrepo JM, erbaum KS. Orthopedic hardware complications diagnosed with multi-detector row CT. Radiology 2005; 237:570 577 18. Daffner RH, Tabas JH. Trauma oblique radiographs of the knee. J one Joint Surg m 1987; 69:568 572 19. Gray SD, Kaplan P, Dussault RG, et al. cute knee trauma: how many plain film views are necessary for the initial examination? Skeletal Radiol 1997; 26:298 302 20. Findlay SC, Eastell R, Ingle M. Measurement of bone adjacent to tibial shaft fracture. Osteoporos Int 2002; 13:980 989 PQI Connect is the latest addition to the RRS Website and serves as a source for information on meeting the growing demand for quality review programs in today s radiology practices and facilities. The interactive and easy-to-navigate site focuses on five critical topics that guide you through news items, relevant articles, and links to important information on each topic. 1360 JR:193, November 2009