Comparison of the Limb Alignment and the Component Positioning between Conventional and Navigated Total Knee Arthroplasties for the Osteoarthritic Knees That Have Anatomic Variation

PURPOSE: The authors sought to assess the usefulness of navigation as opposed to the conventional method by analyzing the radiographic results obtained from subjects who underwent total knee arthroplasty for knees that were accompanied with anatomic variations. MATERIALS AND METHODS: The study subjects were selected from 53 patients (a total 72 cases: 43 were treated by the conventional method and 29 were treated by the navigational method) who exhibited radiographic evidence of distal femoral varus (2degrees). The coronal femoral component angle (alpha) and the coronal tibial component angle (beta) were measured, and the femoral component position in relation to the mechanical axis (theta) and the post-operative weight-bearing mechanical axis difference (MAD) were compared and analyzed. RESULTS: The navigation method showed significant better results in terms of the alpha, theta and MAD (p<0.05). Among the outliers greater than 3degrees, a statistically significant difference was shown only for the MAD (p=0.030). CONCLUSION: Navigation surgery is useful in terms of the femoral component's position in the coronal plane and limb alignment in the osteoarthritic knee that is accompanied by distal femoral varus or proximal tibial varus.

Interface Stability on Insufficient Coverage of Non-cemented Acetabular Cup with Screw Fixations / 대한정형외과학회잡지

PURPOSE: To analyze the effects of various amount of peripheral defect of the acetabulum in terms of the stability of the acetabular cup with screw fixation. MATERIALS AND METHODS: The porous coated acetabular cup of Trilogy was press-fitted with 3 screw fixations after 2 mm undersized reaming into the distal part of 100 bovine femurs, but with insufficient peripheral coverage of 0%, 5%, 10%, 15% and 20% respectively. The micromotions of the acetabular cups were measured under the axial loads of 50, 100, 150, 200, 250, and 300 Kp, and torques were measured at 1degrees to 5degrees of cup rotation under applied rotational force in 10 specimens in each of five groups. RESULTS: The micromotion between the cup and bone interface increased proportionally with peripheral coverage insufficiency and the torque values in the five groups increased in proportion to the rotation degree and were inversely proportinal peripheral coverage insufficiency. CONCLUSION: 15% or less coverage insufficiency of the acetabular cup may be acceptable as the average micromotion is less than 150micrometa and compatible with biologic fixations.

The Effect of Radiofrequency Energy-Induced Thermal Shrinkage on Anterior Cruciate Ligament: An in Vitro Biomechanical Study Using a Rabbit Model

Recently, devices using radiofrequency energy have been developed for arthroscopic soft tissue ablation and shrinkage. The purpose of this study was to evaluate effect of radiofrequency energy on the biomechanical competence of thermal shrinkage of anterior cruciate ligament and was to demonstrate a new approach for radiofrequency energy, applying to ligamentous tissue in a dynamic fashion. Twelve New Zealand White rabbits, were divided into two experimental groups by right and left hindlimbs. Thermal shrinkage of the anterior cruciate ligament of rabbits produced using radiofrequency energy generator(N=12, group I). And untreated control group(N=12, group II). The percent shrinkage was calculated from the change of length of anterior cruciate ligament after radiofrequency energyinduced thermal shrinkage. The maximal tensile stress and linear stiffness of anterior cruciate ligament as biomechanical competence were assessed. The results obtained were as follows: 1. In the group I the percentage of shrinkage was 29.50Fo on the average. 2. The average of maximal tensile stress to failure was 271.24 kN in group I and 283.50 kN in group II. There was no significant difference(p=0.24) in the maximal tensile stress between two groups. 3. The average of linear stiffness in group I(179.16kN/mm) was higher than that of group II(148.20kN/mm). But there was no significant difference(p=0.078) between two groups. This study shows that radiofrequency energy appears to be safe to use on therma1 shrinkage of anterior cruciate ligament, which necessitate a mechanical tensile strength.

Prognostic Factors in Outcome of Operative Treatment of Achilles Tendon Rupture / 대한정형외과학회잡지

PURPOSE: We have evaluated the outcome of the operative treatment of Achilles tendon rupture and analyzed the prognostic factors related to the results. MATERIALS AND METHODS: Subjective assessment of symptoms, range of ankle motion and isokinetic ankle strength was performed on 50 patients during a 1-year follow up. We used a clinical scoring system reported by Leppilahti et al to evaluate the results. RESULTS: The overall results were excellent in 18 (36%), and good in 16 (32%), fair in 10 (20%), and poor in 6 (12%) cases. Lower activity level (P<0.001), presence of systemic disease (P<0.001), later return to physical exercise (P=0.044), and previous Achilles tendon symptoms (P=0.015) were associated with unsatisfactory strength results. An older age (P<0.001) and later return to strenuous activities (P=0.005) were associated with unsuccessful overall results. CONCLUSIONS: We think that a clinical scoring system, including subjective and objective assessment, is good protocol to find the prognostic factors related to the results after the operative treatment of Achilles tendon rupture. The patient group with poor prognostic factors present a challenge for rehabilitation.

Treatment of the Deltoid Ligament Injury in Ankle Fractures Combined with Distal Tibiofibular Diastasis: retrospective study / 대한정형외과학회잡지

PURPOSE: The authors have analysed clinical and radiographic results in 39 cases of the ankle fractures combined with distal tibiofibular diastasis to evaluate the need for surgical repair of the ruptured deltoid ligament. MATERIALS AND METHODS: All of the cases were treated with open reduction and rigid internal fixation for fracture of the distal fibula and trans-syndesmotic screw fixation for the distal tibiofibular diastasis, but ruptured deltoid ligament were treated with surgical or non-surgical methods. The patients were divided into two groups retrospectively. Group I included 24 ankle fractures that were treated with surgical repair for the ruptured deltoid ligament. Group II included 15 patients who were treated conservatively for the ruptured deltoid ligament. RESULTS: The clinical results were excellent in 16 (66.6%), good in 5 (20.8%) in group I, and excellent in 10 (66.6%) and good in 3 (20%) in group II. The radiographic results in reduction of medial joint space were good in 20 (83.3%), fair in 2 (8.3%) in group I, and good in 12 (80%) and fair in 2 (13.3%) in group II at last follow up. CONCLUSIONS: The ruptured deltoid ligament can be treated conservatively if the lateral malleolar fracture and the distal tibiofibular diastasis are stabilized anatomically and the medial joint space is reduced satisfactorily.