Orthopedic personnel roles in the OR for computer assisted total knee arthroplasty

Computer assistance in hip preservation surgery-current status and introduction of our system

INTRODUCTION

Preservation surgery of the hip with open or arthroscopic approach has always been challenging as complex 3-D anatomy and limited surgical access make intraoperative evaluation difficult. Recent advances in computer technology offer a wide range of innovative solutions with a goal to improve accuracy and safety of corrective procedures on human joints.

METHOD

The author critically reviews currently available literature in the field of computer assistance in hip preservation surgery. Basic features of unique planning software and navigation surgical system used in treatment of femoroacetabular impingement and hip dysplasia are introduced.

RESULTS

Currently available software provides preoperative identification of hip deformity on CT-based 3-D model and planning of the surgical correction using kinematic protocols. Real-time intraoperative 3-D orientation is possible, and execution of surgical correction can be performed either with navigation of surgical tools or with printed templates. Computer assistance in hip preservation surgery is in the developing phase. First clinical experiences of its use in treatment of femoroacetabular impingement, hip dysplasia, hip tumors, and avascular necrosis of the femoral head are promising.

CONCLUSION

Computer assistance has been applied for treatment of several hip disorders. Technical advances are suggested and quality basic studies and clinical trials are encouraged for the novel technology to become more user friendly and widely accepted.

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.

Reproducibility of computer-assisted joint alignment measurement in OA knee radiographs

OBJECTIVES

(1) To investigate the reproducibility of computer-assisted measurements of knee alignment angle (KA) from digitized radiographs of osteoarthritis (OA) participants requiring total knee arthroplasty (TKA) and (2) to determine whether landmark choice affects the precision of KA measurements on radiographs.

METHODS

Using a custom algorithm, femoral, central, and tibial measurement-guiding rules were interactively placed on digitized posteroanterior fixed-flexion knee radiographs by mouse control and positioned according to different anatomic landmarks. The angle subtended by lines connecting these guiding rules was measured by three readers to assess interobserver, intraobserver and experience-inexperience reproducibility. Test-retest reproducibility was evaluated with duplicate radiographs from a healthy cohort. Reproducibility was assessed using root-mean square coefficients of variation (RMSCV%). The Bland-Altman method was performed on data obtained from varying anatomic landmarks (confidence interval, CI= 95%).

RESULTS

From 16 healthy and 30 TKA participants, reproducibility analyses revealed a high degree of intraobserver (n=38, RMSCV=0.56%), interobserver (n=38, RMSCV=0.72%), test-retest (n=16, RMSCV=0.87%) and experience-inexperience (n=38, RMSCV=0.73%) reproducibility with variances below 1%. Varying the orientation of tibial and femoral rules according to anatomic landmarks produced a difference that exceeded an a priori limit of agreement of -1.11 degrees to +1.67 degrees.

CONCLUSION

Our custom-designed software provides a robust method for measuring KAs within digitized knee radiographs. Although test-retest analyses were only performed in a healthy cohort, we anticipate a similar degree of reproducibility in an OA sample. A standardized set of anatomic landmarks employed for KA measurement is recommended since arbitrary selection of landmarks resulted in imprecise KA measurement even with a computer-assisted technique.