INTRODUCTION:. It has been reported that rotational deformity is present in varus osteoarthritis (OA) of the knee and the tibia rotates externally as the varus deformity progresses. Although many studies addressed the rotational alignment of the femoral and tibial component in total knee arthroplasty (TKA), the pre-and postoperative changes of the rotational alignment in varus OA knee has not been evaluated. The purpose of this study was to quantitatively analyze the alteration of rotational deformity after TKA for the varus OA knee. METHODS:. Between July 2011 and December 2012, 157 patients (159 knees) with primary varus OA knee undergoing TKA were included. A mobile-bearing, posterior stabilized knee prosthesis was implanted with cement in all patients. Rotational deformities were evaluated with computed tomography (CT) before and after the operation. On the selected CT slices, the relative rotational position of the femur and tibia was quantified as an angle between the line perpendicular to the surgical epicondylar axis of the femur and the line connecting the tibial tubercle tip and the geometric center of the tibia. The knees were divided into three groups according to the preoperative varus deformity (Group I; 0–8° varus, n = 78, Group II; 9–17 ° varus, n = 71 and Group III; 18 ° or greater varus, n = 10) and the difference among the groups were statistically analyzed. RESULTS:. Preoperatively, the average rotational deformity was 6.4 ± 0.9 ° (mean ± SE) external rotation of the tibia relative to the femur. This was significantly corrected to 0.9 ± 0.6 ° external rotation of tibia postoperatively (p < 0.05). The amount of preoperative rotational deformities were not significantly different among the groups (Group I; 6.6 ± 0.9 ° e.r.(external rotation of tibia), Group II; 4.3 ± 1.8 ° e.r., Group III; 5.7 ± 4.1 ° e.r.). Although the rotational deformity wasã��corrected to almost neutral in Group I and II (1.1 ± 0.4 ° e.r. and 1.4 ± 0.9 ° e.r. respectively), there was a tendency with postoperative internal rotation of tibia in Group III (4.2 ± 2.4 ° internal rotation of tibia, p = 0.10). DISCUSSION AND CONCLUSION:. This study has demonstrated that rotational deformity in varus OA knee is significantly corrected after TKA. The knees with less preoperative varus deformity are more likely to be corrected to neutral but substantial rotational mismatch (internal rotation of the tibia) remains in the knees with severe varus deformity. This might be related to the amount of the medial soft tissue release required to obtain correct limb alignment. The surgeons who perform TKA should be aware of the information and carefully check the relative position of the tibial and femoral components especially in the knees with severe varus deformity

Introduction

The most challenging aspect in rotational deformity correction is translating the pre-operative plan to an accurate intra-operative correction. Landmarks away from the osteotomy site are typically employed at pre-operative planning and this can render inadequate correction. Our proposed technique of pre-operative planning using CT scan and leg length radiographs can translate to accurate intra-operative correction.

Introduction: In clinical practice The Cascade sign is widely used to assess the rotational deformity of the fingers associated with metacarpal and phalangeal fractures. We carried out a scientific study on thirty volunteers to evaluate the validity or otherwise of this standard sign.

Material and Methods: Metal pointers were attached to the dorsum of the fingers, flexed at MCP and PIP joints. These pointers represented the mid longitudinal axis of the phalanges. Standardised AP radiographs of the closed fist were taken in all cases with the wrist placed in neutral position, in a custom made jig. The radiographs were assessed by two different observers using Picture Archiving and Communication System, software version VA42B, to determine the convergence of the metal pointers towards the scaphoid tubercle, as described in the cascade sign and Lister method..

Statistics: Power of the study was determined with an assumption of a type-2 error of 0.05 and a two sided test. Descriptive statistics and confidence limits were calculated using SPSS 11 software.

Results: We observed that the metal pointers did not equivocally converge towards the scaphoid tubercle. The persistent pattern of convergence was within a 2–3cm radius of the scaphoid tubercle. The statistical analysis, two tailed paired t-test of this pattern showed strong association with this latter finding. (p< 0.003).

Conclusion: Our study suggests that the cascade sign is sensitive but not specific to access the rotational deformity of the fingers. Radiological there is significant scatter about the scaphoid tubercle.

Rotational defects of the lower limb are frequently encountered and often underestimated. In fact, many symptoms in the lower joint can be related to rotational alteration in the lower leg. These problems are often more visible in the knee joint because they reflect the rotational problems of proximal and distal femur and tibia, respectively. The extensor apparatus, due to the fact that it interacts with both bones, is the more affected joint. Many authors have demonstrated that femoral anteversion increases stress on the patello-femoral joint due to excessive lateralisation of the patella. In the same manner, distal femur internal rotation increases the stress due to altered tracking of the patella during ROM. Valgus knee places stress on the patello-femoral joint, increasing the Q angle and determining a retraction of the lateral structure that causes stress on the lateral patellar face and altered patellar scratch during ROM. External tibial rotation also has been documented to increase the Q angle and patellar tilt, causing excessive stress on the patello-femoral joint. Valgus pronation of the foot, increasing the valgus stress on the knee, can contribute to patello-femoral symptoms, increasing the muscle imbalance at this level. These documented alterations contribute together with other anatomical abnormalities, such as trochlear dysplasia or muscle hypoplasia, in creating the high variability of patello-femoral symptoms that are observed. Rotational deformity of the lower leg therefore represents a frequently encountered pathological condition that must be taken into account when treating patello-femoral symptoms

Pre-operative planning for limb deformity correction involves detailed imaging of the lower limb to define the level, magnitude and direction of deformity. This is then used to plan the correction by defining the centre of rotational alignment (CORA). The method as described by Paley and Hertzenberg involves the use of orthogonal radiographs of the lower limbs using long cassettes (130 cm) taken from a distance of 305 cm to minimize magnification. This method requires special equipment, trained radiographers and multiple doses of radiation even when each radiograph was perfectly positioned first time every time. We present a work in progress replacing the radiographs with a “virtual 3D” CT dataset of the lower limb which we hope will improve the ability to pre-operatively plan deformity correction, but at a lower cost in terms of skill, equipment and dose. Whole limb CT is too costly in terms of time and radiation dose for this to be suitable. New multislice CT systems allow a single coherent study to include segments of unscanned data. Thus it is possible to run a single series through a lower limb to include the articular surfaces, but excluding the diaphyseal segments (gaps). This reduces the radiation exposure to the patient. Such data when entered into suitable DICOM image manipulation software allows the Radiologist or Surgeon to measure and assess the deformity with great precision. Such software is available on the diagnostic radiology workstations but is also available for personal computers, allowing the Surgeon to perform preoperative planning in a numerical modeling setting. Allowing the elements of length, rotation, translation and angulation of the deformity to be measured and corrective surgery tested on the mathematical model. We have compared the measurements taken from a deformity model using this new CT approach and compared it to standard radiographs and found that the above method is no less accurate. Rotational deformities are easier to estimate. However the advantage of our method is that the dataset can be manipulated to determine other technical aspects of deformity correction such as calculating the mounting parameters of the Talyor Spatial Frame. We present worked examples of the methodology showing how this technique improves deformity appraisal