Accuracy of Inter Femoral Head Center Distance Measurement and Evaluation for Coronal Alignment of Femoral Component during Total Knee Arthroplasty / 대한정형외과학회잡지

PURPOSE: Alignment is an important factor in the long-term success of total knee arthroplasty. In the total knee arthroplasty, the conventional extramedullary femoral alignment system has significant error in femoral coronal alignment, since it is difficult to find the femoral head center and it is time consuming to determine during the operation. The purpose of our study was to evaluate the accuracy of the newly-designed marker system for extramedullary femoral alignment that uses radiologic distance between the 2 femoral head centers. MATERIALS AND METHODS: Between July 2008 and July 2009, 90 patients (100 knees) with knee osteoarthritis underwent total knee arthroplasty using the femoral extramedullary femoral guide system. We measured the distance between the femoral head centers using the radiologic picture archiving and communication system (PACS, General Electric, Milwaukee, WI) system preoperatively, then plastic rods and metal pegs were used to simulate the inter femoral head center distance. By placing the center of the plastic rod after marking the inter femoral head center distance on the central body line, we could trace the coronal mechanical axis. We measured the angle between the femoral mechanical axis and the femoral component in standing long leg antero-posterior radiograph to assess radiologically the accuracy of coronal alignment postoperatively. RESULTS: The average femoral length in the study group was 402.5+/-16.2 mm. The mean distance between the femoral head and the center of the marker was 49.6+/-17.9 mm. The average error in estimation of the distance between the femoral head center and the metal peg of the marker was 3.78+/-3.14 mm. The positional error in alignment was 1degrees or less in 90% and 2degrees or less in 100% of knees. The average angle of femoral component to femoral mechanical axis was 89.9+/-1.5degrees (range 84.4-93.6degrees). The coronal alignment of the femoral components was within 90degrees+/-3degrees in -96% of cases. CONCLUSION: Our results suggest that the clinical method reported here is a simple and reliable method to localize the center of the femoral head during total knee arthroplasty.

Arthroscopic Treatment of Fabella Impingement Syndrome after Total Knee Arthroplasty: A Case Report / 대한정형외과학회잡지

Fabella impingement syndrome after total knee arthroplasty (TKA) is a rare condition. However, the location of the inserted prosthesis and the size of the fabella are considered major causative factors. Thus far, a conventional surgical excision of the impinged fabella is recommended treatment for the impingement. A 72-year-old woman was diagnosed with degenerative arthritis of the knee. She complained of fabella impingement due to an incompletely excised bony spur behind the posterolateral femoral prosthesis after TKA. The fabella and remaining bony spur were removed using an arthroscopic procedure. The impingement has not recurred and the range of motion (ROM) of the knee was improved after a 12 months follow-up. Arthroscopic surgery might be an alternative treatment for fabella impingement after TKA.

The Role of Tourniquet in Total Knee Arthroplasty

INTRODUCTION: We prospectively studied the role of tourniquet in total knee arthroplasty by comparing the amount of blood transfusion and postoperative hemovac drainage volume between random samples of tourniquet use group and no tourniquet use group. MATERIAL AND METHODS: Thirty-two cases were operated on with the use of an arterial tourniquet (Group I) and twenty-eight cases without it (Group II). We measured operative time, intraoperative blood loss, postoperative thigh pain, transfusion amount, hemovac drainage and the length of hospital stay. SPSS 10.0 was applied for statistical analysis. RESULTS: There was no significant difference in operative time (119.5 degree+/-19.0 minutes in group I, 118.0degree +/-21.8 minutes in group II), intraoperative blood loss(483.6 degree+/-235.8 cc in group I, 974.2degree030 +/-368.2 cc in group II), postoperative thigh pain(3.8degree ae 0.8 in group I, 1.0degree ae 0.3 in group II), hemovac drainage vol-ume (1369.4 degree+/-516.2 cc in group I, 1400.2 degree+/-344.5 cc in group II), transfusion amount (1530.9degree+/- 575.7 cc in group I, 1404.5degree+/-319.3 cc in group II) and the length of hospital stay(14.5degree+/-3.1 days in group I, 14.9degree+/-6.3 days in group II) between the two groups (p>0.05). Though group I produced less intraoperative bleeding than group II, the postoperative thigh pain was higher. Total hemovac drainage volume of the tourniquet use group was equivalent to that of no tourniquet use group because the hemovac drainage increased abruptly as soon as the tourniquet was released. CONCLUSION: We conclude that tourniquet does not influence significantly on operative time, hemovac drainage, transfusion amount and hospital stay in total knee arthroplasty.

Total Knee Arthroplasty without patellar resurfacing

Patello-femoral problem is one of the common complications in total knee arthroplasty and whether to replace the patella or retain it has long been controversial in order to prevent the complications. 43 cases (35 patients) of total knee arthroplasty with patellar retention performed by a single surgeon between August 1993 and August 2000 were reviewed retrospectively. The follow-up period averaged 54 months (range, 24-120 months). The whole cases were divided into three groups according to the preoperative radiographs. Group A was normal patella (10 knees), Group B was borderline arthritic patella (20 knees), and Group C was severely deformed patella (13 knees). All of 43 knees, regardless of preoperative radiological degree of arthritis received patelloplasty including removal of osteophytes, subchondral shaving and lateral retinacular release was performed in 20 knees (47%). Each groups was evaluated in terms of the objective criteria of anterior knee pain, range of motion, stair climbing ability, and roentgenographic findings. All 35 patients were diagnosed as osteoarthritis in 29 and rheumatoid arthritis in 6. American Knee Society Score (KSS) was assessed for the clinical analysis and lateral patella shift and patella tilt were assessed for roentgenographic analysis. The mean Knee Society Score at final follow-up was 94 in group A, 93 in group B, and 94 in group C. Mild anterior knee pain was reported in 9.3% (Group A: 2 cases, Group C: 2 cases). patellar tilt was significantly higher in C group (oneway ANOVA test, p=0.01), representing that advanced patello-femoral arthritis caused increased patellar tilt. There was neither significant difference in terms of range of motion, and stair climbing ability nor of patellar shift among all three groups. TKA with patelloplasty, not resurfacing the patella, provided satisfactory results without significant problems regardless of the preoperative degree of patello-femoral arthritis.

Risk Period of Osteonecrosis of the Femoral Head in Patients on Steroid Therapy / 대한정형외과학회잡지

PURPOSE: To evaluate the risk period of osteonecrosis of the femoral head following steroid therapy. MATERIALS AND METHODS: Medical records data were reviewed and studied the duration and dosage of steroid therapy for 22 patients who were diagnosed as in the early stage osteonecrosis by MRI but were without positive findings on plain radiographs. RESULTS: The period from the onset of steroid therapy to the time of diagnosis by MRI ranged from one to 16 months (mean, 5.3 months). Twenty-one of the 22 patients were diagnosed within 12 months. The total dosage of steroid ranged from 1,800 to 15,505 mg of prednisolone or its equivalent (mean, 5,928 mg). CONCLUSION: The current study revealed that the risk period for developing femoral head osteonecrosis in patients receiving long-term steroid therapy is 12 months. Periodical follow-up and intensive screening are recommended within the first year of long-term steroid therapy to detect osteonecrosis of the femoral head at an early stage.