Lower limb malrotation following MIPO technique of distal femoral and proximal tibial fractures

Objective

To determine the incidence of rotational malalignment in distal femoral and proximal tibial fractures using computed tomography (CT) scanograms following indirect reduction and internal fixation with the minimally invasive percutaneous osteosynthesis (MIPO) technique.

Design

Prospective Cohort.

Setting

Level I Trauma Centre.

Patients/Participants

A total of 27 consecutive subjects, and 14 proximal tibia and distal femur fractures.

Intervention

All patients underwent indirect reduction and internal fixation with a MIPO plating system. A CT scanogram to measure rotational malalignment between the injured and non-injured extremity was then undertaken.

Main outcome measure(s)

Femoral anteversion angles and tibial rotation angles between the injured and non-injured extremities were compared. Malrotation was defined as a side-to-side difference of >10°.

Results

A total of 14 postoperative tibias and 13 femurs underwent CT scanograms. Three females and 11 males with an average age of 38.1 years sustained proximal tibia fractures and six females and seven males with an average age of 55.8 years sustained distal femur fractures. The difference between tibial rotation in the injured and the non-injured limbs ranged from 2.7 to 40.0° with a mean difference of 16.2° (p = 0.656, paired T-test). Fifty percent of the tibias fixed with MIPO plates were malrotated >10° from the uninjured limbs. The difference between femoral anteversion in the injured and non-injured limbs ranged from 2.0 to 31.3° with a mean difference of 11.5° (p = 0.005, paired T-test). A total of 38.5% of the distal femurs fixed with MIPO plates were malrotated >10° from the uninjured limb.

Conclusions

Following fixation of distal femoral and proximal tibial fractures, the incidence of malrotation was 38.5% and 50%, respectively. The difference of the mean measures was significant for femoral malrotation; however, statistical significance could not be demonstrated for tibial malrotation. The incidence of malrotation following MIPO plating in this study is much higher than that quoted in previous studies.     

Varied influence of the femoral or tibial component on quadriceps angles: Verified by imaging studies

ObjectiveThe aim of this study was to evaluate the varied influence of femoral or tibial component on Quadriceps angles (Q-angle) measured with magnetic resonance image (MRI) and full-length standing scanogram (FLSS) techniques.MethodsTwo groups of patients were studied. The first group underwent MRI studies and the second group underwent FLSS studies. Two-step procedures were carried out. Knee MRI in 60 consecutive adult patients simply taken for meniscus or ligament injuries were utilized at the first step. The standardized patellar center (PC) and tibial tubercle (TT) on the frontal plane of MRI were positioned. At the second step, the FLSS in other 100 consecutive young adult patients taken for chronic unilateral lower extremity injuries were used for locating the two landmarks from MRI. The Q-angle was then determined on the anterior superior iliac spine, standardized PC, and TT on the FLSS.ResultsFor 60 patients, the standardized PC was at the point 42% from the lateral end of the trans-epicondylar line of the femur. The TT was at the point 2 cm distal to the tibial articular surface and 37% from the lateral end of the tibial width. For 100 patients, the Q-angle was an average of 9.5° and 65.2% of the Q-angle was contributed by the upper arm (the femur). Women had a larger Q-angle (10.1° vs. 8.8°, p = 0.02) and a shorter femur (41.1 vs. 44.7 cm, p < 0.001).ConclusionThe Q-angle is about 9.5° with 65.2% contributed by the femur. The Q-angle may mainly be influenced by the femoral component.Level of evidenceLevel IV, Diagnostic Study.     

Limb Length Discrepancy in Total Hip Arthroplasty: Is the Lesser Trochanter a Reliable Measure of Leg Length?

BackgroundLimb length discrepancy (LLD) after total hip arthroplasty may affect clinical outcomes and patient satisfaction. Preoperative LLD estimates on anteroposterior pelvic radiographs fail to account for anatomical limb variation distal to the femoral reference points. The objective of this study is to determine how variations in lower limb skeletal lengths contribute to true LLD.MethodsFull-length standing anteroposterior radiographs were used to measure bilateral leg length, femoral length, and tibial length. Leg length was evaluated using 2 different proximal reference points: the center of the femoral head (COH) and the lesser trochanter (LT). Mean side-to-side discrepancy (MD) and percentage asymmetry (%AS) for each measurement were evaluated in the overall cohort and when stratified by patient demographic variables.ResultsOne hundred patients were included with an average age of 62.9 ± 11.2 years. Average femoral length was 434.0 ± 39.8 mm (MD 4.3 ± 3.5 mm) and tibial length was 379.9 ± 34.6 mm (MD 5.9 ± 12.7 mm). Average COH-talus was 817.5 ± 73.2 mm (MD 6.4 ± 5.1 mm). Average LT-talus was 760.5 ± 77.6 mm (MD 5.8 ± 5.1 mm). Absolute asymmetry >10 mm was detected in 16% of patients for COH-talus and 15% for LT-talus, while %AS >1.5% was detected in 13% of patients for COH-talus and 18% for LT-talus. Female gender was associated with increased femoral length %AS (P = .037).ConclusionApproximately 1 in 6 patients have an LLD of >10 mm when measured from either the LT or COH. Surgeons using either of these common femoral reference points to estimate LLD on pelvic radiographs should consider these findings when planning for hip reconstruction.Level of EvidenceLevel III.     

Comparison of CT scanograms and cephalometric radiographs in craniofacial imaging

Objective– To compare measurements from human skulls and their images from cephalometric radiographs (CR) and computed tomography (CT) scanograms, in order to gauge the potential clinical use of the latter. Design– Based on specific inclusion criteria, including stable centric occlusion, 13 adult skulls were selected from a larger collection. The mandible was taped to the maxilla after securing the occlusion of teeth and condylar seating in the glenoid fossa. Lateral and posteroanterior cephalographs and CT `scout views' were taken of each skull by standardized methods. Landmarks were identified on skulls and images. Outcome Measures– Linear measurements were made on all three records; angular measurements only on CR and CT images. Intraclass correlation coefficients (r) were calculated to assess similarity among records. Paired t‐tests were used to compare differences between mean measurements. Results– No statistically significant differences were noted between mean angular values on CR and CT views (P > 0.05). The highest correlations were observed for several vertical midline distances between CT and direct skull measures: 0.82 < r < 0.995–greatest for nasion–menton. For sagittal distances, the highest correlation was between the direct measure of condylion–pogonion and its CR image (r=0.73). Correlations between CR and skull transverse measures were higher (0.46 < r < 0.80) than the corresponding skull vs. CT measures (0.06 < r < 0.38). CT and CR images are 2D slices and projections, respectively, of 3D structures. Vertical CT and skull measures correspond because the CT projection reflects a 1 : 1 ratio in the midsagittal plane; CT projected lateral images are smaller than the skull measures. The CR image reflects a distortion (～8%) that brings Co–Pg closer to its anatomic distance, inadvertently contributing to better clinical planning, particularly in orthognathic surgery. The pattern of distortion of PA images was in opposite directions for CR and CT views. Conclusions– Cephalograms and CT scanograms are close in depicting angular relations of structures, but they differ in the accuracy of imaging linear measurements, because the location and size of an object within the imaged 3D structure varies with both records. Logistic and economic considerations favor the use of cephalographs.     

Combination of whole-spine lateral radiograph and lateral scanogram in the assessment of global sagittal balance

Background Context

Global balance of human standing is analyzed as the geometric sum of the individual alignments extending from the spinal column to the pelvis, and to the lower limbs. The innovative EOS system has opened new perspectives for the global analysis of whole-body alignment, but its use is very limited because of its high cost. An alternative may be to combine the whole-spine lateral radiograph and the lateral scanogram in the global sagittal analysis of whole-body alignment.

ASSESSING LEG LENGTH DISCREPANCY AFTER FEMORAL FRACTURE: CLINICAL EXAMINATION OR COMPUTED TOMOGRAPHY?

INTRODUCTION: Femoral shaft fractures treated with intramedullary nailing often heal with a leg length discrepancy (LLD). LLD is commonly evaluated by clinical examination and computed tomography (CT) scanogram. We assessed the correlation between these two techniques of calculating LLD. METHODS: We reviewed 35 skeletally mature patients who sustained a femoral shaft fracture between January 1997 and December 1999. Leg length was measured clinically with direct measurement and a block test. Each patient was asked whether they felt they walked with a limp and whether they felt they had a leg length discrepancy. Each patient underwent a CT scanogram to measure femoral and total leg length. The correlation between clinical examination and scanogram was analysed using the Pearson Product Moment Correlation. RESULTS: Of the 35 patients, 15 patients (43%) had a measurable LLD. There was a positive correlation between direct leg length measurement and the block test (P = 0.003), and between the block test and patient perception of limp and LLD. CT scanogram was performed on 29/35 patients. There was no correlation between CT scanogram and clinical measurement of leg length or between CT scanogram and patient perception of LLD or limp. DISCUSSION: Leg length discrepancy commonly occurs following treatment of femoral shaft fractures. We found that there was a strong correlation between direct leg length measurement and the block test, and between both methods of clinical leg length measurement and patient perception of a limp or LLD. Our study found no correlation between CT scanogram and clinical leg length measurement or patient perception of limp or LLD. CONCLUSION: Our study shows that physical examination (direct measurement and the block test) is more reliable and clinically relevant than CT scanogram measurement in the assessment of LLD after femoral fracture.