Similar radiological results with accelerometer-based navigation versus conventional technique in total knee arthroplasty.

BACKGROUND: The Zimmer iASSIST system is an accelerometer-based, portable navigation device for total knee arthroplasty (TKA) that does not require the use of a large console for alignment feedback as required in computer-assisted surgery. The purpose of this study was to determine the accuracy of the accelerometer-based system in component positioning and overall mechanical alignment. METHODS: Two groups of 30 patients each with primary osteoarthritis underwent TKA using either conventional method or Zimmer iASSIST navigation in 2013 was retrospectively studied. Patients were matched according to body mass index (BMI), gender and age. A senior arthroplasty surgeon performed all the operation using the same surgical approach. Perioperative and post-operative regimens were the same. All patients had standardized radiographs performed post-operatively to determine the lower limb mechanical alignment and component placement. RESULTS: There was no difference between the two groups for age, BMI, gender, side of operated knee and preoperative mechanical axis ( p > 0.05). There was no difference in the proportion of outliers for mechanical axis ( p = 0.38), coronal femoral angle ( p = 0.50), coronal tibia angle ( p = 0.11), sagittal femoral angle ( p = 0.28) and sagittal tibia angle ( p = 0.33). The duration of surgery, post-operative drop in haemoglobin level and transfusion incidence did not show statistically significant differences between the two groups ( p > 0.05). CONCLUSIONS: Our article showed that iASSIST was safe and remains a useful tool to restore mechanical axis. However, our data demonstrated no difference in lower limb alignment and component placement between the TKA that used accelerometer-based system and those that underwent conventional method.

A new technique of arthroscopic subscapularis repair with 2-year clinical outcomes in an Asian population.

BACKGROUND: Tears of the subscapularis are not as common as the other rotator cuff muscles and hence not as many arthroscopic repair techniques have been previously described in the literature. The purpose of this study is to evaluate the clinical outcomes in patients undergoing arthroscopic subscapularis repairs (with and without repairs of the other cuff muscles) using a technique devised by the senior author of this study. METHODS: A retrospective study of 40 consecutive patients who underwent arthroscopic subscapularis repair at a single centre, by a single surgeon from 2009 to 2014. All patients were assessed preoperatively and post-operatively at 3, 6, 12 and 24 months. The Visual Analogue Scale (VAS), Constant-Murley Shoulder Score (CMSS), University of California at Los Angeles (UCLA) Shoulder Score and Oxford Shoulder Score (OSS) were recorded and used. RESULTS: At 24 months follow-up, the VAS for pain improved from 6 (±2) points preoperation to 0 (±1) points. The CMSS improved from 41 (±18) points preoperation to 71 (±15). The relative CMSS improved from 55 (±24%) preoperation to 96 (±22%; % of the uninjured side). The ULCA Shoulder Score improved from 15 (±5) points preoperation to 30 (±4). The OSS improved from 28 (±12) points preoperation to 45 (±5). p < 0.001 for all outcomes measured. CONCLUSION: Overall clinical outcomes are favourable at 2 years post-operatively. The described technique is an effective method for arthroscopic subscapularis repair in the Asian population.