Search

Lateral condylar prominence is a common problem after corrective osteotomy of the cubitus varus, which is believed to result from unequal opposing cut surfaces of lateral-based wedge osteotomy using a medial hinge. This study investigated this issue using a 3-dimensional CT data set consisting of images of the deformed elbow and the normal elbow of a patient with cubitus varus deformity who was scheduled for corrective osteotomy A CT scan was performed with 3mm slice thickness and a reconstruction was done with 1mm interpolated slice thickness on both the left and right humerus. The CT-data set was then manipulated using reverse engineering software. Three-dimensional models of both the deformed and normal humeri were studied. Several locations or levels of medial hinge placement, each with 4-degree-tilt wedge osteotomy cut options, were then virtually performed and evaluated. The degree of correction was determined from the varus angle plus the normal carrying angle of the normal side. From the study, it was found that the degree of lateral condylar prominence is directly proportional to the distance of placement of the medial hinge above the joint. Differences in the lengths of the osteotomy surfaces have no effect on condylar prominence; only the step-off phenomenon affects condylar prominence. According to our findings, placement of the medial hinge close to the joint with a 10-degree distal osteotomy cut just above the olecranon fossa will result in optimal minimization of condylar prominence or the step-off phenomenon.

This paper proposes a novel method of using an antero-posterior buttress screw at the distal fragment just below the fracture site in conjunction with the sliding hip screw (SHS) to resist excessive femoral medialisation. A virtual assessment of the effectiveness of this new method was performed using the finite element analysis. The results indicate that the use ofa sliding hip screw (SHS) combined with a buttress screw can help resistfemoral medialisation better than using an SHS with no buttress screw. The von Mises equivalent stress (EQ ) was found to be in a safe range, which indicates increased integrity of the lateral wall with the addition of the buttress screw.

Objective: To investigate the optimal entry point for retrograde femoral nailing using medical imaging and reverse engineering technologies., Material and Method: One hundred and eight adult cadaveric femurs were scanned using a computed tomography (CT) scanner. To obtain three-dimensional models, medical imaging and reverse engineering technologies were used. The insertion assessment was performed using computer aided design (CAD) software. The curve representing the mid-line in the intramedullary canal in the mid-shaft region was approximated using regression analysis. The curve was extended tangentially toward the femoral condyle, where the intersection between the curve and the condylar surface is the insertion site. The location of the insertion site was determined using the center of the anterior most of the intercodylar notch as a reference point. The measured distances were presented in medial-lateral and anterior-posterior perspectives from the reference point., Results: Average insertion site for Thai population was 0.56 mm lateral to and 12.67 mm medial to the anterior most of the intercondylar notch. The distance measured from intercondylar notch to the insertion site in the anterior-posterior direction was not significantly different between males and females; however a significant difference in the insertion site was found in medial-lateral directions., Conclusion: The insertion site can be clinically approximated lying on the anterior-posterior axis, since the distance from the anterior-posterior axis to the insertion site is relatively small. The insertion site for the Thai population was found to be 12 mm anterior to the center of the anterior most of the intercondylar notch.

Objective: To compare the radiation exposure of the primary surgeon while using the conventional c-arm and mini c-arm fluoroscopy at the shoulder, Material and Method: Twelve shoulders of six fresh cadavers were used to simulate this experimental study. Radiation exposure of the primary surgeon was measured at the head and neck region. The average radiation dose was measured using both the conventional c-arm and mini c-arm, then the findings were compared., Results: Mean radiation energy of the conventional c-arm was significantly lower than the mini c-arm at 59.39 ± 1.43 kV and 70.58 ± 4.01 kV respectively (p < 0.001). Dose rates to which the primary surgeon was exposed from the conventional c-arm and the mini c-arm were 81.46 ± 30.37 μSv/hour and 87.54 ± 43.69 μSv/hour, respectively. However, the difference was not statistically significant (p = 0.875)., Conclusion: There is no difference in the level of radiation safety for the primary surgeon when using the conventional c-arm vs. the mini c-arm for a fluoroscopic-assisted shoulder procedure. Therefore, selection of the methodology should be based on equipment availability and clinical considerations.

Background: Heterotopic ossification is defined as pathological bone formation in soft tissue, it usually occurs postoperatively and varies in amount from faint to massive ossification, which are frequently asymptomatic. The cause of heterotopic ossification is unknown, but it occurs more commonly after the procedure, in which considerable bone and soft tissue are dissected extensively. The heterotopic ossification in the abductor region of the hip following closed femoral nailing has rarely been documented., Objective: To assess the prevalence and type of heterotopic ossification after closed antegrade femoral nailing., Material and Method: A retrospective study was performed in patients who underwent closed antegrade femoral nailing. The occurrence of heterotopic bone was assessed by reviewing of the series of the follow-up films in this group of patients with sufficient duration of at least after 6 months post-operation. The size and extent of the heterotopic ossification were measured and graded according to Brumback classification., Results: From 100 patients who were completely followed-up. There were 54 cases (54%) presented with heterotopic ossification. The heterotopic ossification are classified as grade I in 16 cases (16%), grade II in 13 cases (13%), grade III in 24 cases (24%) and grade IV in 1 case (1%). There was a significant different between the prevelence of heterotopic ossification in patients with trochnateric fractures when compared to patients with femoral shaft fractures (p-value < 0.05).

The tourniquet pain during 30 minutes after the application of calf tourniquet and ankle tourniquet were assessed and compared in 63 healthy volunteers, 32 males and 31 females whose ages ranged from 21-36 (average, 24) years. The visual analogue pain score assessed at 0, 1, 3, 5, 10, 20, 30 minutes of adequate tourniquet pressure application and after removal of the tourniquet at 0, 5 and 30 minutes were recorded. The results revealed significant less visual analogue pain scores with the ankle tourniquet group (range, 0-4.4 mmHg) than the calf tourniquet group (range, 0-6.7 mmHg) at all time-points of evaluations and the tourniquet pain was also diminished faster in the ankle tourniquet group after the tourniquet was removed. It was also found a significant higher minimal tourniquet pressure required for the vascular occlusion distal to the tourniquet sites detected by a pulse oximeter in the ankle tourniquet group (mean, 310.8 +/- 40.8 mmHg) than the calf tourniquet group (mean, 272.5 +/- 36.9 mmHg, p = 0.024). The present study supports the use of ankle tourniquet to minimize tourniquet pain for foot surgery.

Seventy-six cadaveric humeri were investigated to study the three-dimensional morphometric data based on CT data. The present study was an advanced method to determine the 3D proximal humeral parameters for both intra and extra geometries through the utilization of medical imaging and reverse engineering techniques. The following parameters were calculated for each humerus and then compared with the 3D Caucasian data such as diameter of humeral head, articular surface thickness, inclination angle, retroversion angle, medial offset, posterior offset, curve length, radius of curvature, and mediolateral angle. It was found that the Thai humeral parameters were smaller than Caucasian except the retroversion angle and posterior offset. This data could be further used to develop a proper design of shoulder arthroplasty for Thai patients.

Objective: Investigate the 2D/3D geometry of femoral curvature and femoral length using the advanced technique of computerized tomography combined with reverse engineering techniques., Material and Method: The present study was performed using reverse engineering technique based on CT data of 99 cadaveric femora. The femur was divided into three segments, proximal, mid-shaft, and distal regions by defining 35% and 65% of the femoral total length as a boundary of each region. The intramedullary canal in the mid-shaft region was mainly extracted to determine the set of circular center, which could consequence to approximate the 3D femoral radius of curvature using the 3D least square best fit. The 3D femoral curvature was then projected into A-P and M-L directions to investigate the correlation of 2D/3D femoral curvature as normal radiographic images., Results: It was found that the average 3D Thai femoral curvature was 895.46-mm (SD = 238.06) and the average femoral total length is 421.96-mm (SD = 27.61). In addition, the 2D femoral curvature derived from sagittal radiographic image can be used to determine the 3D femoral curvature with this equation: R3D = RSagittal + 3.67 with r = 0.987., Conclusion: This described technique is a non-destructive method that can effectively assess the internal/ external 3D geometric data of the femur The obtained data is useful to develop a proper design of prosthesis that required inserting into the intramedullary canal. From the present study, it can be concluded that the 2DSagittal femoral curvature derived from standard radiographic image can be represented for the 3D femoral curvature.

A prospective study of the radiation exposure to the primary surgeon during closed static locked femoral nailing was performed in 50 cases. There were 44 males and 6 females whose ages ranged from 15 to 70 years (average, 32). The degree of fracture comminution was classified by Winquist. The cases included 1 Winquist (WQ)1, 9 WQ2, 27 WQ3 and 13 WQ4. The Grosse-Kempf femoral nail was used in 40 cases and the AO interlocking femoral nail was used in 10 cases. The C-arm image intensifier model Phillip BV212 and BV 300 were used during the present study. The average operation time was 52 minutes (range, 30 to 120). The fluoroscopic time for the entire procedure average 132 seconds (range, 23 to 366). The radiation exposure to the primary surgeon ranged from 2 to 231 micro-Sv with an average of 30 micro-Sv per procedure. From the present study, it was found that radiation scattered to the primary surgeon during current practice for closed static femoral nailing using the recent model of C-arm image intensifier was minimal and far below the permissible dose. It was also found that the group using the C-arm model BV 300 (n = 16) had significant lesser fluoroscopic time and less radiation scattering to the primary surgeon than the group with model BV 212 (n = 34).

The present study present a three-dimensional virtual simulation method to evaluate the fit-and-fill effect of the insertion of a trochanteric gamma nail (TGN) in 98 Thai dadaveric proximal femora. The circular best fit of the 2-dimensional cross-section of the femoral canal and the nail at 4 levels [d100, d120, d140 and d160] which were located at 100, 120, 140 and 160 mm distal to the tip of the greater trochanter were calculated. The evaluation of each level included, 1) the diameters of the medullary canal, 2) the percentage of area filled by the nail in the unreamed medullary canal, 3) the minimal reamer diameter that required enlargement of the canal to accommodate TGN insertion, 4) the minimal inner cortical reaming thickness that needed to be removed, 5) the percentage of cortical bone area that needed to be removed prior to nail insertion and 6) the deviation of the nail center from the center of the medullary canal. The results showed that at 4 studied locations the diameter of unreamed medullary canal averaged 10.3 to 11.8 mm. The nail cross-section that could fill the medullary canal averaged 86.9-95.1%. The minimal reaming diameter for the medullary canal to accommodate the TGN insertion averaged 11.3 to 12.3 mm. The inner cortical thickness that should be removed averaged 0.6 to 0.8 mm. The cortical bone that needed to be removed averaged 13.6 to 19.3% of the total cortical area. The deviation of the nail center from the canal center averaged 0.3 to 0.8 mm. The present study showed some mismatching of the TGN to that of the Thai proximal femur. Appropriate reaming to prepare the medullary canal should be considered prior to TGN insertion to prevent technical problem. Future re-design of the implant may be considered for Thai patients.