Minimal invasive and computer-assisted total knee replacement compared with the minimal invasive technique: a prospective, randomized trial with short-term outcomes.

INTRODUCTION: Up to now, no prospective, randomized comparisons between minimal invasive and computer-assisted total knee arthroplasty (MICA-TKA), and minimal invasive technique (MI-TKA) has been documented to evaluate not only clinical, but also radiologic results of the MICA-TKA. This prospective, randomized study was performed to compare the short-term results of MICA-TKA with minimal invasive technique MI-TKA for 6-month follow-up.

PATIENTS AND METHODS: We reported the clinical and radiological results of 80 subjects who had cruciate-substituting, TKA-implanted primary total knee arthroplasties using either minimal invasive and computer-assisted technique (40 patients Group I) or minimal invasive technique (40 patients, Group II). Tourniquet time, length of skin incision, and total blood loss were compared. Knee society scores (KSSs), knee society functional scores (KSFSs), range of motion (ROM), and radiographic results were assessed and reported preoperatively and at 6-month follow-up.

RESULTS: The accuracy of the implantations in relation to the coronal mechanical axis in Group I was superior to that of Group II (P < 0.05). The femoral rotational profile revealed the prosthesis in Group I that was implanted with significantly less internal rotation than in Group II. The average blood loss in patients of Group I was significantly reduced as compared to patients of Group II. No significant difference was detected in terms of tourniquet time or length of skin incision. Clinical results, with regard to ROMs and KSSs, as well as KSFSs were equally good in both the groups.

CONCLUSIONS: Better alignment and similarity of good clinical results at short-term follow-up may provide subjects who receive MICA-TKA with long-term endurance of their implants. Further studies on longer-term outcomes and functional improvements are required to validate these possibilities.