Is Immediate Postoperative Mechanical Axis Associated with the Revision Rate of Primary Total Knee Arthroplasty? A 10-Year Follow-up Study

BACKGROUND: Achieving neutral limb alignment during total knee arthroplasty (TKA) has been considered an important determinant in the long-term prosthesis survival. The purpose of this study was to evaluate the association between the immediate postoperative mechanical alignment of the lower limb and the rate of revision TKA by comparing an acceptable mechanical axis group (within ± 3° from neutral alignment) and an outlier group (> 3° deviation from neutral alignment). METHODS: Between 2000 and 2006, clinical and radiographic data of 334 primary TKAs were retrospectively reviewed to determine the 10-year Kaplan-Meier survival rate. Patients were divided into acceptable and outlier groups according to the mechanical axis checked postoperatively within a month. Clinical outcomes were assessed using Hospital for Special Surgery, Knee Society Score, and Western Ontario and McMaster Universities Osteoarthritis Index score preoperatively and at the final follow-up. Postoperative complications and revision rates were also evaluated. RESULTS: The mean change in mechanical axis between the immediate postoperative examination and the last follow-up was greater in the outlier group (1.6 ± 2.7) than in the acceptable group (0.8 ± 2.4). The revision rates were significantly different between the two groups (p = 0.04). At the last follow-up, clinical scores were all improved in both groups compared to each preoperative condition. There were no significant differences in clinical scores between the two groups at the last follow-up. The 10-year Kaplan-Meier survival analysis showed a tendency towards better survival with restoration of neutral mechanical axis. However, the difference was not statistically significant (p = 0.25). CONCLUSIONS: Restoration of neutral limb alignment is a factor that can result in a lower revision rate and higher longevity in TKA. However, there were no significant differences in clinical outcomes between the two groups.

Deformities of the Lower Extremities in Hereditary Multiple Exostoses / 대한정형외과학회잡지

PURPOSE: This study was done to analyze the alignment and deformity of the lower extremity in hereditary multiple exostoses patients. MATERIALS AND METHODS: We enrolled 32 patients who were diagnosed as having hereditary multiple exostoses (HME) between January 2001 and December 2007. Based on age at diagnosis, we categorized them into 4 groups, A (0-5 years: 6 patients), B (6-10 years: 7 patients), C (11-15 years: 7 patients) and D (>16 years: 12 patients). We measured mechanical axis deviation, This included femorotibial mechanical angle (a), inferolateral angle (b), femoral mechanical proximal anatomical angle (c), femoral mechanical distal anatomical angle (d), distal tibia inferolateral angle (e) and femoral neck-shaft angle (f). We analyzed for differences among the groups of different ages. RESULTS: The average femorotibial mechanical angles (a) of Groups A/B/C/D were respectively, 178.5degrees/180.3degrees/182.5degrees/183.5degrees (p<0.05). Distal tibia inferolateral angles (e) were respectively, 91.9degrees/93.5degrees/94.2degrees/102.9degrees (p<0.05). The mechanical axis deviation of groups A, B, C, and D, respectively, were 1.7 mm, 6.0 mm, 9.6 mm, and 13.4 mm (p<0.05) on the right side, and 2.9 mm, 7.6 mm, 12.2 mm, and 15.2 mm (p<0.05) on the left side. CONCLUSION: Patients with HME have a tendency towards having valgus deformities of the knee and ankle joints, which tend to increase with age.

Robotic Total Knee Arthroplasty: Minimal Follow-up of 3 Years

PURPOSE: We wanted to evaluate the clinical and radiographic results of robotic-assisted implantation of TKAs with a minimum follow-up of three years. MATERIALS AND METHODS: 50 TKAs using ROBODOC(R) (Integrated Surgical Systems, Sacramento, CA, USA) were included in this study. We assessed the radiographic measurements with regard to the change of the mechanical axis and the inclination of the femoral and tibial components. The clinical results were evaluated with using the range of motion (ROM), the Hospital for Special Surgery (HSS) scores and the Western Ontario and McMaster University (WOMAC) scores. RESULTS: The angle formed by the mechanical axis of the femur and tibia was corrected from 6.57degrees varus to 0.49degrees valgus. The mean coronal inclination of the femoral and tibial components was 89.52degrees and 90.12degrees, respectively, and the mean sagittal inclination of the femoral and tibial components was 1.06degrees and 85.56degrees, respectively. There were 45 excellent and 5 acceptable results for the femoral component, and 38 excellent and 11 acceptable results for the tibial components. On the clinical assessment, the ROM improved from 124.9degrees to 128.4degrees, and the improvements of the HSS and WOMAC scores were 70.06 to 95.72 and 65.64 to 28.92, respectively. CONCLUSION: A surgical robot system that has the ability to execute highly precise preoperative planning and intraoperative procedure for TKA provides good clinical and radiographic results at three years follow-up.

The Midterm Results of Arthroscopic Anterior Cruciate LigamentReconstruction with Hamstring Tendon and Ligament Anchor Screw / 대한정형외과학회잡지

PURPOSE: To evaluate the clinical and radiological results of an arthroscopic ACL reconstruction with a hamstring tendon and Ligament Anchor (LA) screw. MATERIALS AND METHODS: 48 cases among 47 patients with a minimum 5 year follow up after the ACL reconstruction were examined. The clinical results (Lysholm Knee score, Tegner activity scale, Lachmann test, Pivot-shift test, and complications) were evaluated, and the radiological results (osteoarthritis, bony tunnel enlargement, instrumented anterior laxity test with Telos?) were assessed. RESULTS: The Lysholm Knee score showed significant improvement from 65.8 to 96.7 at the final follow up. The Tegner activity scale also showed significant improvement from 3.5 preoperatively to 6.0 at the final follow-up. The Lachmann test showed that 42 cases had converted to negative. The Pivot-shift test was negative in 39 cases and mild positive in 9 cases. The side to side difference using the instrumented anterior laxity test was 12.5 mm preoperatively and 3.2 mm at the final follow-up. Degenerative osteoarthritis was observed in 9 (19%) knees. The femoral and tibial tunnel were widened by 21.6 and 20.9% in the AP view and 16.3 and 19.0% in the lateral view, respectively (p<0.05). CONCLUSION: An ACL reconstruction with a hamstring tendon and LA screw can restore the knee stability with satisfactory clinical results and few complications.