Radiologic Outcomes According to Varus Deformity in Minimally Invasive Surgery Total Knee Arthroplasty

Outcomes of total knee replacement with the use of a NexGen MIS Tibial Component (Mini-keel) : a systematic review

NexGen MIS Tibial Component (Mini-keel) is a tibial component specially developed for minimally invasive surgery in total knee replacement (TKR), and the size limitations of its design and the modular system could affect tibial fixation strength, however, this has not been precisely evaluated thus far. This study aimed to systematically review the literature describing the outcome following TKR with the use of a Mini-keel. Electronic searches of databases were undertaken in July 2019 by two experienced orthopaedic surgeons according to the PRISMA guidelines for literature describing the outcomes of TKR with the use of a Mini-keel. Quality of studies was assessed using the Joanna Briggs Institute Critical Appraisal Checklist. The initial search found a total of 623 studies from all the databases. Seven studies met all the inclusion criteria and were eligible for critical appraisal and quality assessment. In total, 2,198 cases were included in the systematic review. Thirty-five revision cases due to aseptic loosening were found from the systematic review. Two studies were negative about using a Mini-keel and three studies were positive about it, while the other two studies did not judge the quality of a Mini-keel. There have been conflicting conclusions among studies for the use of a Mini-keel. There remains a paucity of prospective cohort studies between TKRs with the use of a Mini-keel and those with the use of a conventional implant, which makes it difficult to determine the usefulness and reliability of this implant.

[A prospective randomized controlled study of total knee arthroplasty via mini-subvastus and conventional approach]

Objective

To compare the clinical and radiographic results between primary total knee arthroplasty (TKA) via mini-subvastus or conventional approach through a prospective randomized controlled study.

Methods

Ninety-four patients (104 knees) undergoing primary TKA between January 2011 and April 2012 were evaluated and randomly divided into 2 groups. Forty-six patients (52 knees) underwent TKA via conventional approach (conventional approach group), and 48 patients (52 knees) underwent TKA via mini-subvastus approach (mini-subvastus approach group). In these patients, 45 cases (51 knees) in conventional approach group and 45 cases (49 knees) in mini-subvastus approach group were followed up and recruited in the final analysis. There was no significant difference in age, gender, body mass index, sides, osteoarthritis grading, American Knee Society Score (KSS), Hospital for Special Surgery (HSS) score, visual analogue scale (VAS), range of motion (ROM) of knee between 2 groups ( P>0.05). The clinical indexes were recorded and analyzed, including the operation time, length of incision, total blood loss, blood transfusion after operation, hospital stay time, the time of performing straight leg raise, incision condition, VAS score, ROM of knee, HSS score, and KSS score, hip-knee-ankle angle (HKA), femoral anatomic axis and the femoral prosthesis joint angle (femoral angle), tibia anatomic axis and tibial prosthesis joint angle (tibial angle), femoral prosthesis flexion angle (FPFA), and posterior slope angle (PSA) of the tibial plateau.

Results

All patients were followed up. The average follow-up time was 66.4 months (range, 60.0-72.5 months) in conventional approach group and 65.6 months (range, 60.0-71.2 months) in mini-subvastus approach group. Compared with the conventional approach group, the incision of mini-subvastus approach group shortened, the operation time prolonged, and the time when patients started straight leg raise exercises was earlier; showing significant differences between 2 groups ( P<0.05). There was no significant difference in hospital stay time, total blood loss, and numbers of blood transfusion between 2 groups ( P>0.05). The complication rate was 8.2% (4/49) in mini-subvastus approach group and 0 in conventional approach group, showing no significant difference between 2 groups ( P=0.054). At 1 and 3 days, the VAS and the ROM of knee in mini-subvastus approach group were significantly better than those in conventional approach group ( P<0.05); but there was no significant difference in above indexes between 2 groups at 14 day ( P>0.05). There was no significant difference in HSS and KSS scores between 2 groups at the 1, 3, 6, 12 months and 3, 5 years ( P>0.05). X-ray film showed no aseptic loosening in all cases. There was no significant difference in the measured values and incidence of abnormal patient of HKA, femoral angle, tibial angle, FPFA, and PSA at last follow-up between 2 groups ( P>0.05).

Conclusion

TKA via mini-subvastus approach is helpful to the early function recovery of knee, but the long-term effectiveness is consistent with TKA via conventional approach. As the limited exposure, TKA via mini-subvastus spproach may has high risk of operative complications.

Interactive Surgery System with 3D Electromagnetic Motion Tracker for Training Surgeons in Skin Cutting Skills Needed in Total Knee Arthroplasty

Total knee arthroplasty (TKA) is an effective surgery for knees damaged by osteoarthritis, rheumatoid arthritis, and post-traumatic arthritis. This procedure requires an expert surgeon with a high level of skill and experience. Although a navigation system for improving precision and shortening operative time has been already studied, there has not yet been a study done on an instruction system for improving the skills of surgeons. The purpose of this study is to develop a training system that teaches the TKA surgery so that non-expert surgeons can use it to obtain skin-cutting skills. The proposed method includes a simulator for a model knee with a 3D electromagnetism motion tracker. Through experimentation, a method of evaluating incisions into the skin is established by tracing a line with a mock scalpel. The proposed method is applied to six non-experts. The results for the length experiments are 87.82±8.88 (Set 1: non-teaching), 92.66±5.77 (Set 2: teaching), and 92.14±6.17 (Set 3: non-teaching). The results for the position experiments are 70.64±15.11 (Set 1: non-teaching), 83.63±10.07 (Set 2: teaching), and 82.05±7.80 (Set 3: non-teaching). In conclusion, the proposed method succeeds in teaching the operator scalpel incision skills.

Revision Arthroplasty Using a MUTARS® Prosthesis in Comminuted Periprosthetic Fracture of the Distal Femur

Periprosthetic fractures after total knee arthroplasty (TKA) are gradually increasing, reflecting extended lifespan, osteoporosis, and the increasing proportion of the elderly during the past decade. Supracondylar periprosthetic femoral fracture is a potential complication after TKA. Generally, open reduction and internal fixation are the conventional option for periprosthetic fracture after TKA. However, the presence of severe comminution with component loosening can cause failure of internal fixation. Although the current concept for periprosthetic fracture is open reduction and internal fixation, we introduce an unusual case of revision arthroplasty using a MUTARS® prosthesis for a comminuted periprosthetic fracture in the distal femur after TKA, with technical tips.