Kostenanalyse zur Navigation in der Knieendoprothetik

Robotic-assisted TKA reduces surgery duration, length of stay and 90-day complication rate of complex TKA to the level of noncomplex TKA

INTRODUCTION

Complex primary total knee arthroplasties (TKA) are reported to be associated with excessive episode of care (EOC) costs as compared to noncomplex procedures. The impact of robotic assistance (rTKA) on economic outcome parameters in greater case complexity has not been described yet. The purpose of this study was to investigate economic outcome parameters in the 90-days postoperative EOC in robotic-assisted complex versus noncomplex procedures.

MATERIALS AND METHODS

This study is a retrospective, single-center review of 341 primary rTKAs performed between 2017 and 2020. Patient collective was stratified into complex (n = 218) and noncomplex TKA (n = 123) based on the presence of the following criteria: Obese BMI, coronal malalignment, flexion contracture > 10°, posttraumatic status, previous correction osteotomy, presence of hardware requiring removal during surgery, severe rheumatoid arthritis. Group comparison included surgery duration, length of stay (LOS), surgical site complications, readmissions, and revision procedures in the 90-days EOC following rTKA.

RESULTS

The mean surgery duration was marginally longer in complex rTKA, but showed no significant difference (75.26 vs. 72.24 min, p = 0.258), neither did the mean LOS, which was 8 days in both groups (p = 0.605). No differences between complex and noncomplex procedures were observed regarding 90-days complication rates (7.34 vs. 4.07%, p = 0.227), readmission rates (3.67 vs. 3.25%, p = 0.841), and revision rates (2.29 vs. 0.81%, p = 0.318).

CONCLUSIONS

Robotic-assisted primary TKA reduces the surgical time, inpatient length of stay as well as 90-days complication and readmission rates of complex TKA to the level of noncomplex TKA. Greater case complexity does not seem to have a negative impact on economic outcome parameters when surgery is performed with robotic assistance.

Comparative Cost Analysis of Four Different Computer-Assisted Technologies to Implant a Total Knee Arthroplasty over Conventional Instrumentation

Several computer-assisted technologies, such as navigation and robotics, have been introduced to Total Knee Arthroplasty (TKA) in order to increase surgical precision and reduce complications. However, these technologies are often criticized due to the increased costs and effort associated with them; however, comparative data are missing. The aim of the present study was to evaluate differences in intraoperative workflows and the related perioperative cost-profiles of four current computer-assisted technologies, used to implant a TKA, in order to gain a comparison to conventional instrumentation. For the cost analysis, additional preoperative imaging and instruments, increased operating room (OR) and planning-time, and expenditures for technical support of the equipment and disposals were calculated, in comparison to conventional TKA, for (1) standard computer-navigation, (2) patient specific instruments (PSI), (3) image-based robotic assistance, and (4) imageless robotic assistance. Workflows at four expert centers which use these technologies were reviewed by an independent observer. The total cost calculation was based on a 125 TKA per year unit in Switzerland. Computer-navigation resulted in 14 min (+23%) increased surgery time and, overall, USD 650 in additional costs. PSI technology saved 5 min (8%) OR time but it created USD 1520 in expenditures for imaging and disposals. The image-based robotic system was the most expensive technology; it created overall additional costs of USD 2600, which predominately resulted from technical support, disposals, the CT-Scan, and 14 min of increased OR time. The imageless robotic assistance resulted in the largest increase in OR-time, as it resulted in an additional 25 min (+42%) on average. Overall, additional costs of USD 1530 were calculated. Every one of the assistive technologies in this study increased the total cost of TKA when compared to a conventional technique, and the most important variables, related to cost, were technical support and additional disposables. The longer surgical times and additional surgical trays required for the techniques had a marginal effect on overall costs. This comparative cost analysis gives valuable information for future efforts to calculate the real costs of these technologies and the subsequent return on investment of each technique.

Computer-Assisted Orthopedic and Trauma Surgery

BACKGROUND

There are many ways in which computer-assisted orthopedic and trauma surgery (CAOS) procedures can help surgeons to plan and execute an intervention.

METHODS

This study is based on data derived from a selective search of the literature in the PubMed database, supported by a Google Scholar search.

RESULTS

For most applications the evidence is weak. In no sector did the use of computer-assisted surgery yield any relevant clinical or functional improvement. In trauma surgery, 3D-navigated sacroiliac screw fixation has become clinically established for the treatment of pelvic fractures. One randomized controlled trial showed a reduction in the rate of screw misplacement: 0% with 3D navigation versus 20.4% with the conventional procedure und 16.6% with 2D navigation. Moreover, navigation-assisted pedicle screw stabilization lowers the misplacement rate. In joint replacements, the long-term results showed no difference in respect of clinical/functional scores, the time for which the implant remained in place, or aseptic loosening.

CONCLUSION

Computer-assisted procedures can improve the precision of certain surgical interventions. Particularly in joint replacement and spinal surgery, the research is moving away from navigation in the direction of robotic procedures. Future studies should place greater emphasis on clinical and functional results.

Encouraging treatment algorithm for computer-assisted navigated total knee arthroplasty (TKA): A retrospective cohort analysis

OBJECTIVE

Navigated computer-assisted total knee arthroplasty (TKA) shows inconclusive mid- to long-term outcome results and is limited by increased costs, surgery-time and an additional learning curve. We introduced a treatment algorithm preserving computer-assisted TKA for patients with adipositas-per-magna, posttraumatic leg-deformities, osteosynthetic material in-situ or reduced preoperative X-ray quality.

METHODS

237 primary unilateral TKA were allocated based on the treatment concept described above. A retrospective pre- and postoperative radiological analysis was performed.

RESULTS

222 TKA (93.7%) were within 3° varus/valgus of mechanical-lower-limb axis (mean absolute deviation: 1.8° ± 1.3°).

CONCLUSION

This algorithm showed an excellent postoperative implantation-accuracy based on an accurate preoperative surgery-planning.

TKA for Posttraumatic Osteoarthritis Is More Complex and Needs More Surgical Resources

The purpose of this study was to evaluate the surgical effort of total knee arthroplasty (TKA) for posttraumatic osteoarthritis (PTOA) compared with primary osteoarthritis (OA). A total of 1841 TKAs were analyzed, including 170 patients with PTOA, that resulted from soft tissue trauma in 83 patients and fractures in 87 patients. Results showed that patients were significantly younger at the time of surgery in the posttraumatic group (62 vs 71 years; P<.001). Furthermore, fracture was associated with 3.7 years earlier need of TKA compared with soft tissue trauma. Operation time was significantly longer for both of the posttraumatic groups compared with OA (P<.001). Patients undergoing TKA after knee injuries are younger and surgical treatment is more challenging compared with TKA for OA. Extended operation time and implant systems with higher constraint and modular options are required. [Orthopedics. 2016; 39(3):S36-S40.].

Navigated TKA After Osteotomy Versus Primary Navigated TKA: A Matched-Pair Analysis

This article presents clinical and radiological outcome analysis of navigated total knee arthroplasty (TKA) following osteotomy compared with primary navigated TKA implantation. The study group (29 legs) received navigated TKA (Columbus with deep-dish, cruciate-retaining inlay, Aesculap AG, Tuttlingen, Germany) following distal femoral (6 legs) or high tibial (23 legs) osteotomy, and the control group (29 legs) received a primary navigated TKA. All patients were examined clinically and radiologically in a retrospective matched-pair analysis. Both groups showed comparable clinical scores (Oxford Knee Score, Tegner and Lysholm scores, and Knee Society Score). Radiological evaluations offered no relevant differences. The study group showed a significant mediolateral ligamentous instability (3 legs ≤5°, 1 leg 6°-9°, 25 legs ≥10° mediolateral deviation) compared with the control group (14 legs ≤5°, 9 legs 6°-9°, 6 legs >10°; P<.001). Significantly higher mediolateral ligamentous instability was seen in otherwise comparable clinical and radiological results in patients with navigated TKA implantation following osteotomy, compared with primary TKA. [Orthopedics; 2016. 39(3):S77-S82.].

Intraoperative fluoroscopy improves surgical precision in conventional TKA

PURPOSE

The purpose of this study was to assess whether intraoperative fluoroscopy assists in the restoration of the coronal limb alignment target in conventional total knee arthroplasty (TKA).

METHODS

One hundred and six patients undergoing conventional cemented TKA were randomly assigned to be operated on with or without intraoperative fluoroscopy. The image intensifier, together with customized manual instrumentation, was used for separately measuring the frontal alignment of the femoral and tibial resection surfaces. The surgeon adjusted the resection surfaces when a mechanical axis deviation error angle of ≥ 0.5° was observed on the fluoroscopic image. Coronal alignment was measured on standing long-leg digital radiographs.

RESULTS

Patients operated with fluoroscopy assistance had (1) a lower risk of malalignment at the threshold of >3° (risk ratio, 0.7; 95 % CI, 0.13-1.2), (2) a mean fluoroscopic time of 3 s, and (3) a longer operative time (69 vs. 60 min, p < 0.001). The American Knee Society Score was not different between the two groups at 1-year follow-up.

CONCLUSION

This new surgical intervention appears to offer an effective means for improving the precision of TKA alignment in the coronal plane.

No difference between computer-assisted and conventional total knee arthroplasty: five-year results of a prospective randomised study

PURPOSE

The use of computer-assisted surgery (CAS) in total knee arthroplasty (TKA) results in better limb and implant alignment compared to conventional TKA; however, it is unclear whether this translates to better mid- to long-term clinical outcome. This prospective randomised study comparing CAS and conventional TKA reports the functional and patient perceived outcomes at a follow-up of 5 years. The hypothesis was that there would be a difference in functional outcome or quality of life after mid-term follow-up.

METHODS

Sixty-seven patients were available for physical and radiological examination at 5 years. The Knee Society Score (KSS) was used to describe functional outcome and the Euroquol questionnaire for quality of life.

RESULTS

The mean total KSS for the CAS group improved from 91.1 (SD 22.3) points preoperatively to 157.4 (SD 21.9) and 150.2 (SD 30.4) points at 2 and 5 years, respectively. In the conventional group, the mean total KSS was 99.6 (SD 18.6) points preoperatively and 151.1 (SD 26.0) and 149.0 (SD 28.0) points at 2 and 5 years, respectively. The mean quality of life score improved from 48.2 (SD 16.5) points preoperatively to 67.4 (SD 16.3) and 66.8 (SD 22.2) points at 2 and 5 years in the CAS group, and from 52.2 (SD 17.1) points preoperatively to 65.6 (SD 14.6) and 61.7 (SD 19.3) points at 2 and 5 years, respectively, in the conventional TKA group. These differences were not statistically significant. There were radiolucent lines up to 2 mm in 11 knees (four CAS, seven conventional), but there were no changes in implant position.

CONCLUSIONS

There were no significant differences in functional or patient perceived outcome after mid-term follow-up in this study.

LEVEL OF EVIDENCE

I.

Navigation in minimally invasive unicompartmental knee arthroplasty has no advantage in comparison to a conventional minimally invasive implantation

INTRODUCTION

Minimally invasive implantation of unicompartmental knee prostheses can shorten rehabilitation time and lead to better functional results than conventional implantation. Exact positioning of the implant should be achieved, as this is a factor for the long-term survival of the prosthesis, although malpositioning can result due to the poor intraoperative view when using the minimally invasive approach. Navigation of the unicompartmental prosthesis could lead to a better implant positioning without losing the advantages of a minimally invasive approach.

MATERIALS AND METHODS

The same unicondylar knee prosthesis was implanted in a total of 40 patients, of whom 20 were implanted using navigation (kinematic navigation) and 20 using a conventional technique. The operating time was assessed in both groups. The orientation of the tibial and femoral implants was assessed radiologically postoperatively. We analysed these results according to the optimal positioning range proposed by the manufacturer. Furthermore, we examined the clinical results with the knee society score (KSS).

RESULTS

A good positioning of the prosthesis was observed in both techniques with only 11% of the radiologic measurements out of the proposed optimal range in each group. The operating time was significantly longer in the navigation group (17 min). The KSS did not differ between both groups at a follow-up of 16 resp. 18 months (navigated group: 184 points, conventional group: 178 points).

CONCLUSIONS

Navigation did not lead to a better positioning of the prosthesis than the conventional method and the operating time was longer. The clinical results were similar in both groups. The navigation may be a useful help for surgeons performing less unicompartmental knee arthroplasty using a minimally invasive approach.

Displays mounted on cutting blocks reduce the learning curve in navigated total knee arthroplasty

The use of computer navigation in total knee arthroplasty (TKA) improves the implant alignment but increases the operation time. Studies have shown that the operation time is further prolonged due to the surgeon's learning curve, and longer operation times have been associated with higher morbidity risks. It has been our hypothesis that an improvement in the human-machine interface might reduce the time required during the learning curve. Accordingly, we asked whether the use of navigation devices with a display fixed on the surgical instruments would reduce the operation time in navigated TKAs performed by navigation beginners. Thirty medical students were randomized and used two navigation devices in rotation: these were the Kolibri® device with an external display and the Dash® device with a display that was fixed on the cutting blocks. The time for adjustment of the tibial and femoral cutting blocks on knee models while using these devices was measured. A significant time reduction was demonstration when the Dash® device was used: The time reduction was 21% for the tibial block (p = 0.007), 40% for the femoral block (p < 0.001), and 32% for the whole procedure (p < 0.001). The integrated display, fixed on surgical instruments in a manner similar to a spirit level, seems to be more user-friendly for navigation beginners. Hence, unproductive time losses during the learning curve may be diminished.

Intraoperative radiographs for placing acetabular components in hip resurfacing arthroplasty

BACKGROUND

Various clinical and biomechanical studies suggest certain acetabular positions may be associated with higher wear and failure rates in modern metal-on-metal hip resurfacing arthroplasties. However, there are no widely available, reliable, and cost-effective surgical techniques that ensure surgeons are able to place an acetabular component within the safe range of inclination angles after hip resurfacing surgeries.

QUESTIONS/PURPOSES

We investigated the accuracy of intraoperative radiographs to determine the acetabular inclination angle in resurfacing arthroplasty procedures.

PATIENTS AND METHODS

The study group included the first 100 resurfacing arthroplasties performed after we started routinely checking the intraoperative acetabular inclination angles. The acetabular component was repositioned if the intraoperative acetabular inclination angle was out of the target range of 30° to 50°. The control group included the previous 100 resurfacing arthroplasties performed without the benefit of intraoperative radiographs. A posterior minimally invasive surgical approach was used in both groups. Demographics and diagnoses were similar in both groups.

RESULTS

The average (± SD) difference between the intraoperative and 6-week radiographs was 2.7° ± 2.5°. The acetabular inclination angles at 6-week followup were within the targeted range more frequently in the study group than in the control group (outliers: 4% versus 29%).

CONCLUSIONS

These data suggest a single intraoperative radiograph is a quick, reliable, and cost-effective method for ensuring the acetabular inclination angle is within the targeted range.

Functional outcome after computer-assisted versus conventional total knee arthroplasty: a randomized controlled study

Despite the frequent use of computer-assisted total knee arthroplasty (TKA) and better radiological results for coronal alignment reported in many studies, there is still no evidence of improved clinical outcomes when compared to conventional TKA. We compared alignment after navigated TKA and conventional TKA in 80 randomized patients. Seventy three patients were available for physical and radiological examination at 20 month after surgery. Both groups showed similar Knee Society Score results, with medians of 89 points (navigated 49-95 points, conventional 48-95 points, n.s.) in the Knee Score and 70 points (navigated 45-100 points, conventional 40-100 points, n.s.) in the Function Score. The median improvement in the Knee Society Knee Score was 45 points (-3 to 88 points) in the navigated group and 35 points (-13 to 62 points) in the conventional group (P = 0.03), and the Knee Society Function Score improvement was 15 points (-10 to 50 points) in the navigated group versus 10 points (-10 to 50 points) in the conventional group (n.s.). The current health state at follow-up using the EuroQuol questionnaire was similar in both groups, with medians of 67 points in the navigated group and 65 points in the conventional group. This investigation did show slightly greater functional improvement at short-term follow-up in the navigated TKA group. Longer follow-up will be required to assess the possible benefit of computer-assisted navigation.