Radiological outcomes of pinless navigation in total knee arthroplasty: a randomized controlled trial

Navigated Versus Conventional Total Knee Arthroplasty: A Systematic Review and Meta-analysis of Prospective Randomized Controlled Trials

Background

Recent evidence on the cost-effectiveness of technology in total knee arthroplasty (TKA) demonstrated that navigated computer-assisted methods (N-TKA) is likely to be most cost-effective in the clinical setting. The aim of the current meta-analysis is to compare radiographic, clinical and functional outcomes between conventional TKA (C-TKA) and N-TKA methods.

Methods

All prospective randomized controlled trials (pRCTs) comparing primary TKA performed using C-TKA and N-TKA techniques were eligible for inclusion. Radiographic outcomes included postoperative coronal, sagittal and axial component alignment. Clinical outcomes included all-cause revision and aseptic revision. Functional outcomes were analyzed when reported. A random-effects meta-analysis of all available cases was performed. This allowed for all missing data.

Results

Normal coronal mechanical alignment of the tibial (p < 0.001) and femoral (p = 0.001) components was achieved more frequently with N-TKA. Normal sagittal mechanical alignment of the tibial component was achieved significantly more with N-TKA (p < 0.010). There was no difference in short-term clinical survivorship (all-cause, p = 0.649; aseptic, p = 0.79) or in functional outcomes reported between groups. There was a clinically significant reduction in the mean C-TKA operative time (87 min, σ = 16.6, 95% CI 76.4-98.8) compared N-TKA (97.6 min, σ = 16.9, 95% CI 86.2-109.1) (p = 0.17).

Conclusion

Navigated TKA achieves superior radiographic alignment for femoral and tibial components in both the coronal and sagittal plane. Operative times are 10 min longer in the N-TKA group. Functional outcomes are similar between navigated and conventional groups. Clinical outcomes reported in Level I studies are limited to short-term follow-up so future prospective studies are required.

No differences in long-term clinical outcomes and survival rate of navigation-assisted versus conventional primary mobile-bearing total knee arthroplasty: A minimum 10-year follow-up

PURPOSE

This study aimed to compare long-term clinical and radiographic outcomes and survival rates between navigation-assisted (NAV) total knee arthroplasty (TKA) and conventional (CON) TKA using a mobile-bearing insert.

METHODS

From May 2008 to December 2009, 45 and 63 mobile-bearing TKA patients were enroled in the CON- and NAV-TKA groups with 146.8 months follow-up, respectively. Clinical outcomes (Western Ontario and McMaster University Osteoarthritis Index and Knee Society Scores), radiographic outcomes (hip-knee-ankle [HKA], lateral distal femoral, medial proximal tibial, γ, and δ angles), and survivorship were compared between both groups.

RESULTS

The number of HKA angle outliers (more than 3 degrees or less than -3 degree) was significantly lower in the NAV-TKA group (24.4% vs. 9.5%, p = 0.036) than in the CON-TKA group. However, long-term clinical outcomes were similar between both groups. The cumulative survival rate (best-case scenario) was 98.3% in the CON-TKA group and 97.5% in the NAV-TKA group, with no significant difference between the groups (p = 0.883).

CONCLUSION

Long-term clinical outcomes and survival rates were similar between the two groups despite fewer outliers of postoperative lower-limb alignment in the NAV-TKA group. Excellent survival rates were observed in both groups using mobile-bearing inserts.

LEVEL OF EVIDENCE

Level IV, case series.

Navigated functional alignment total knee arthroplasty achieves reliable, reproducible and accurate results with high patient satisfaction

PURPOSE

The decision on which technique to perform a total knee arthroplasty (TKA) has become more complicated over the last decade. Perceived limitations of mechanical alignment (MA) and kinematic alignment (KA) have led to the development of the functional alignment (FA) philosophy. This study aims to report the 2-year results of an initial patient cohort in terms of revision rate, PROMs and complications for Computer Aided Surgery (CAS) Navigated FA TKA.

METHODS

This paper reports a single surgeon's outcomes of 165 consecutive CAS FA TKAs. The final follow-up was 24 months. Pre-operative and post-operative patient-reported outcome measures, WOMAC and KSS, and intra-operative CAS data, including alignment, kinematic curves, and gaps, are reported. Stress kinematic curves were analysed for correlation with CAS final alignment and CAS final alignment with radiographic long-leg alignment. Pre- and post-operative CPAK and knee phenotypes were recorded. Three different types of prostheses from two manufacturers were used, and outcomes were compared. Soft tissue releases, revision and complication data are also reported.

RESULTS

Mean pre-operative WOMAC was 48.8 and 1.2 at the time of the final follow-up. KSS was 48.8 and 93.7, respectively. Pre- and post-operative range of motion was 118.6° and 120.1°, respectively. Pre-operative and final kinematic curve prediction had an accuracy of 91.8%. CAS data pre-operative stress alignment and final alignment strongly correlate in extension and flexion, r = 0.926 and 0.856, p < 0.001. No statistical outcome difference was detected between the types of prostheses. 14.5% of patients required soft tissue release, with the lateral release (50%) and posterior capsule (29%) being the most common.

CONCLUSION

CAS FA TKA in this cohort proved to be a predictable, reliable, and reproducible technique with acceptable short-term revision rates and high PROMs. FA can account for extremes in individual patient bony morphology and achieve desired gap and kinematic targets with soft tissue releases required in only 14.5% of patients.

LEVEL OF EVIDENCE

IV (retrospective case series review).

Comparison of the radiographic outcomes and total blood loss between pinless navigation and conventional method in minimally invasive total knee arthroplasty

Background

Computer-assisted surgical navigation has been used in total knee arthroplasty (TKA) procedures for years trying to the accuracy of prosthesis placement. We conducted this prospective randomized clinical trial to compare the accuracy of the radiographic parameters of the prosthesis, total blood loss (TBL), and related complications, between a new pinless navigation system (Stryker OrthoMap Express Knee Navigation) and conventional method in patients undergoing minimally invasive (MIS) TKA procedures.

Patient and methods

A consecutive series of 100 patients underwent unilateral primary TKA were randomly assigned into two groups: navigation group and convention group. The radiographic parameters of the knee implant and the alignment of lower limb were measured at 3 months after surgery. TBL was calculated according to Nadler’s method. The duplex ultrasonography of both lower limbs was performed in all patients to detect the presence of deep-vein thrombosis (DVT).

Results

Totally, 94 patients have completed the radiographic measures. Only the coronal femoral component angle in the navigation group (89.12° ± 1.83°) had significant differences from that in the convention group (90.09° ± 2.18°) (p = 0.022). There were no differences in the rate of outliers. The mean TBL in the navigation group was 841 ± 267 mL, which was similar to that in the convention group at 860 ± 266 mL (p = 0.721). Postoperative DVT risk did not differ between the two groups (2% vs. 0%, p = 0.315).

Conclusion

This pinless navigation TKA showed a comparable acceptable alignment compared with conventional MIS-TKA. There were no differences regarding postoperative TBL between the two groups.

Navigated and Robot-Assisted Technology in Total Knee Arthroplasty: Do Outcome Differences Achieve Minimal Clinically Important Difference?

BACKGROUND

In total knee arthroplasty (TKA), computer-assisted navigation (N-TKA) and robotic-assisted methods (RA-TKA) are intended to increase precision of mechanical and component alignment. However, the clinical significance of published patient-reported outcome measure (PROM) differences in comparison to conventional TKA (C-TKA) is unknown.

METHODS

A systematic review was performed to identify all studies reporting perioperative PROMs for either primary N-TKA or RA-TKA with a C-TKA comparison cohort with a minimum 1-year follow-up. Relative improvements in PROMs for the two cohorts were compared to published minimal clinically important difference (MCID) values.

RESULTS

After systematic review, 21 studies (N = 3,214) reporting on N-TKA and eight studies (N = 1,529) reporting on RA-TKA met inclusion criteria. Eighteen of 20 studies (90%) reported improved radiographic outcomes with N-TKA relative to C-TKA; five of five studies reported improved radiographic outcomes with RA-TKA relative to C-TKA. Five of 21 studies (24%) reported statistically significant greater improvements in clinical PROMs for N-TKA relative to C-TKA, whereas only two (10%) achieved clinical significance relative to MCID on a secondary analysis. One of 8 studies (13%) reported statistically significant greater improvements in PROMs for RA-TKA relative to C-TKA, whereas none achieved clinical significance relative to MCID on a secondary analysis. No studies reported a significant difference in revision rates.

CONCLUSION

While most studies comparing RA-TKA and N-TKA with C-TKA demonstrate improved radiographic alignment outcomes, a minority of studies reported PROM differences that achieve clinical significance. Future studies should report data and be interpreted in the context of clinical significance to establish patient and surgeon expectations for emerging technologies.

Fragility Index as a Measure of Randomized Clinical Trial Quality in Adult Reconstruction: A Systematic Review

Background

The Fragility Index (FI) and Reverse Fragility Index are powerful tools to supplement the P value in evaluation of randomized clinical trial (RCT) outcomes. These metrics are defined as the number of patients needed to change the significance level of an outcome. The purpose of this study was to calculate these metrics for published RCTs in total joint arthroplasty (TJA).

Methods

We performed a systematic review of RCTs in TJA over the last decade. For each study, we calculated the FI (for statistically significant outcomes) or Reverse Fragility Index (for nonstatistically significant outcomes) for all dichotomous, categorical outcomes. We also used the Pearson correlation coefficient to evaluate publication-level variables.

Results

We included 104 studies with 473 outcomes; 92 were significant, and 381 were nonstatistically significant. The median FI was 6 overall and 4 and 7 for significant and nonsignificant outcomes, respectively. There was a positive correlation between FI and sample size (R = 0.14, P = .002) and between FI and P values (R = 0.197, P = .000012).

Conclusions

This study is the largest evaluation of FI in orthopedics literature to date. We found a median FI that was comparable to or higher than FIs calculated in other orthopedic subspecialties. Although the mean and median FIs were greater than the 2 recommended by the American Academy of Orthopaedic Surgeons Clinical Practice Guidelines to demonstrate strong evidence, a large percentage of studies have an FI < 2. This suggests that the TJA literature is on par or slightly better than other subspecialties, but improvements must be made.

Level of Evidence

Level I; Systematic Review.

The Fragility of Statistically Significant Findings From Randomized Controlled Trials in Hip and Knee Arthroplasty

BACKGROUND

The Fragility Index (FI) is a method for evaluating the robustness of statistically significant findings from randomized controlled trials (RCTs) beyond the P value in trials with dichotomous outcomes. The FI is defined as the number of patients in one arm of a trial that would have to have a different outcome to change the results of the trial from statistically significant to nonsignificant. This review assessed the FI in arthroplasty RCTs.

METHODS

A systematic search was conducted in MEDLINE, Embase, and Web of Science for RCTs related to primary total joint arthroplasty (TJA) from 2010 to 2020. Trials with a statistically significant dichotomous primary outcome were included. The FI was calculated using Fisher's exact test to determine how many events would need to be reversed to change a study from statistically significant to nonsignificant.

RESULTS

A total of 34 RCTs were included. The median sample size was 103 patients (range 24-791). The median FI was 1 (range 0-45), meaning that reversing the outcome of just one patient in either treatment group of each trial would change it from a significant to a nonsignificant result.

CONCLUSION

Hip and knee arthroplasty RCTs with statistically significant dichotomous outcomes in TJA are fragile. The median FI in TJA is lower than the FI in any of the other previously reported orthopedic subspecialties. Fragility is another reason to be cautious when conducting or interpreting small trials, and to continue to strive toward large trials to answer important questions in TJA.

LEVEL OF EVIDENCE

Level I.

Pinless Navigation in Unicompartmental Knee Arthroplasty

Purpose: In contrast to total knee arthroplasty (TKA), unicompartmental knee arthroplasty (UKA) is a true resurfacing procedure, as none of the ligaments are replaced or released, and the pre-arthritic leg alignment is the major goal. As such, the alignment of the tibial component plays a crucial role in postoperative knee function and long-term survival. Pinless navigation has shown reliable results in total knee arthroplasty. To the best of our knowledge, the use of pinless navigation has not been investigated for UKA. Therefore, the present study investigated whether implantation of the tibial component in 3° varus, which is closer to the anatomical axis, is feasible with a pinless optical navigation system. Methods: 60 patients with the diagnosis of an unicompartmental arthritis, were eligible for UKA and treated with implantation in 3° varus alignment of the tibial component. Two groups were established. In the treatment group the tibial component was aligned using a pinless navigation technique. In the control group, a conventional extramedullary alignment guide was used. A clinical and radiographic follow up took place within 1 year of operation. Results: 57 Patients were eligible for analysis. No clinical incidents were noted in the follow up period. The desired target value, the position of the tibial component, was accurately achieved with an average of 3° medial inclination using the pinless navigation as well as using the conventional technique. Mean incision to suture time was negligible between the two techniques. The mean suture time was 43.2 min with pinless navigation and 42.7 min with the conventional technique. Conclusions: With pinless navigation in UKA, a method was presented that made it possible to achieve sled prosthesis alignment at the level of a high-volume surgeon. These results were achieved with an irrelevant increase of surgical time and without placement of pins.

A review of computer-assisted orthopaedic surgery systems

BACKGROUND

Computer-assisted orthopaedic surgery systems have great potential, but no review has focused on computer-assisted surgery systems for the spine, hip, and knee.

METHODS

A systematic search was performed in Web of Science and PubMed. We searched the literature on computer-assisted orthopaedic surgery systems from 2008 to the present and focused on three aspects of systems: training, planning, and intraoperative navigation.

RESULTS AND DISCUSSION

In this review study, we reviewed 34 surgical training systems, 31 surgical planning systems, and 41 surgical navigation systems. The functions and characteristics of the surgical systems were compared and analysed, and the current concerns about and the impact of the surgical systems on doctors and surgery were clarified.

CONCLUSION

Computer-assisted orthopaedic surgery systems are still in the development stage. Future surgical training systems should include synthetic models with patient anatomy. Surgical planning systems with automatic planning should be developed, and surgical navigation systems with multimodal fusion, robotic assistance and imaging should be developed.

Comparison of a novel handheld accelerometer-based navigation system and conventional instrument for performing distal femoral resection in total knee arthroplasty: a randomized controlled trial

Background

This prospective study aimed to compare the efficacy of a novel, hand-held, accelerometer-based navigation system (i-JOIN knee navigation system) for distal femoral resection in total knee arthroplasty (TKA) with conventional instrument.

Methods

A multi-center, double-blinded, randomized controlled trial (RCT) was conducted. A total of 79 consecutive patients scheduled for primary TKA were enrolled and divided into navigation group (39 patients) and conventional group (40 patients). Post-operative mechanical and component position were evaluated through full-leg weight bearing X-ray. Pre-operatively and 1 week post-operatively, adverse events were recorded. Intraoperative surgical time and blood loss were also recorded.

Results

The mean outlier of 180° neutral mechanical axis was 1.60° (SD 1.11°) in navigation group and 2.30° (SD 2.06°) in conventional group (P=0.0917). Thirty-eight patients (97.4%) in navigation group and 35 patients (87.5%) in conventional group had an alignment which was ≤3°away from the neutral mechanical axis (P=0.2007). α angle between the navigation group and conventional group was not statistically different (89.81° vs. 89.76°, P>0.05), as well as adverse events rate post-operatively. The operative time of navigation group was significantly longer than that of control group (114.54±35.34 vs. 100.33±28.38 min, P=0.0493), whereas the intraoperative blood loss was not significantly different.

Conclusions

i-JOIN knee navigation system had equivalent results for distal femoral resection in TKA compared with the conventional technique.

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.

Intraoperative validation of bone cut accuracy of a pinless smart touch-screen navigation system device in total knee arthroplasty

PURPOSE

Primary objective in most of the published literature on computer-assisted total knee arthroplasty (TKA) has so far been the comparison of axial alignment and components position, obtained either through navigation systems or through conventional instrumentation. We have found no studies aimed at assessing the intraoperative reliability of a navigation system in relation to bone cuts height. Aim of our study was therefore to establish bone cut accuracy of a pinless navigation system.

METHODS

From January 2014 to February 2016, 44 consecutive patients requiring total knee replacement (TKR) were enrolled in a prospective study. Primary end point of the study was to assess the accuracy of the DASH iPOD TOUCH Navigation System (Brainlab AG, Feldkirchen, Germany) by measuring the real thickness of both tibial and femoral osteotomies. We compared the data indicated by the navigation system with the intraoperative anatomical measurements done with the aid of a caliper. In addition, the radiographic alignment was compared with the data derived from the navigator.

RESULTS

The device proved to be precise. Differences between the two methods of measurement are distributed over a millimeter range. Radiological measurements showed that 95.5% of tibial components were within the range of 3° varus/valgus; same results were obtained by the navigation system; instead, 90.1% of femoral components were within the range of 3° varus/valgus based on the radiological measurement, whereas according to the navigation system, 86.4% were in this range.

CONCLUSIONS

The DASH iPOD TOUCH Navigation System is a precise and reliable instrument to assist in TKA navigation.

The accuracy of a hand-held navigation system in total knee arthroplasty

INTRODUCTION

This study aims to evaluate the effectiveness of a new hand-held navigation system. The authors of this study hypothesize that this navigation system will improve overall lower limb alignment and implant placement without causing a delay in surgery.

PATIENTS AND METHODS

Two hundred consecutive patients diagnosed with tricompartmental osteoarthritis and underwent total knee arthroplasty by a senior surgeon were included in this study. One hundred patients underwent TKA using the hand-held navigation system, while the other 100 patients underwent TKA using the conventional technique. The primary outcomes of this study were the overall alignment of the lower limb and the position of the components. This was determined radiologically using the: (1) Hip-Knee-Ankle angle (HKA) for lower limb alignment; (2) Coronal Femoral-Component angle (CFA); and (3) Coronal Tibia-Component angle (CTA) for component position. Normal alignment was taken as 180° ± 3° for the HKA and 90° ± 3° for both the CFA and CTA.

RESULTS

For the CFA, the proportion of outliers was 7 and 17% in the hand-held navigation and conventional group, respectively (p = 0.030). For the HKA and CTA, there was no difference in the proportion of outliers between the two groups. The duration of surgery was 73 ± 9 min and 87 ± 15 min in the hand-held navigation and conventional group, respectively (p < 0.001).

CONCLUSION

This hand-held navigation system is an effective intraoperative tool for reducing the proportion of outliers for femoral implant placement as well as the duration of surgery. The authors conclude that it can be considered for use to check femoral implant placement intra-operatively.

LEVEL OF EVIDENCE

III.

Clinical outcomes of computer-assisted total knee arthroplasty using pinless navigation

This study aims to evaluate the 2-year post-operative clinical outcomes of patients undergoing total knee arthroplasty (TKA) with computer-assisted surgery (CAS) using the pinless BrainLAB^® VectorVision^® Knee 2.5 Navigation System versus standard CAS. A retrospective case-control study of 200 patients who underwent TKA with CAS from 2008 to 2012 was conducted. Patients in the pinless arm underwent a shorter duration of surgery compared to the standard CAS arm with 72 ± 13 min and 83 ± 11 min, respectively ( p < 0.001), with improvement in Oxford Knee Score from 34 ± 8 to 18 ± 5 and 34 ± 9 to 18 ± 5, respectively, without statistically significant differences in clinical outcomes at 2 years.

Computer-assisted stereotaxic navigation improves the accuracy of mechanical alignment and component positioning in total knee arthroplasty

INTRODUCTION

This study reports on a novel computer-assisted stereotaxic navigation (CASN) system that attempts to combine the accuracy of computer navigation with familiarity of conventional methods. We hypothesize that CASN would improve mechanical alignment and component positioning when compared to conventional instrumentation.

MATERIALS AND METHODS

145 patients (192 knees) retrospectively matched for age, BMI, gender and pre-operative scores, underwent total knee arthroplasty (TKA) using CASN (n = 92) or conventional instrumentation (n = 100). Pre- and post-operative radiological alignment [Acceptable ranges: mechanical axis (MA) 0° ± 3°, coronal femoral-component angle (CFA) and coronal tibia-component angle (CTA) 90° ± 3°] and clinical outcomes (Knee Society Scores, Oxford Knee Score and Short Form-36) at 6 months were examined.

RESULTS

The CASN group had significantly improved mean MA (1.9° ± 1.4°, versus 2.8° ± 2.0° in the conventional group, p = 0.001), CFA (1.6° ± 1.3°, versus 2.1° ± 1.5° in the conventional group, p = 0.035) and CTA (1.6° ± 1.2°, versus 2.1° ± 1.5° in the conventional group, p = 0.024). 91.3 % of knees in the CASN group were within 3° of a neutral mechanical axis, versus 74 % in the conventional group (p < 0.001). The duration of surgery was significantly longer in the CASN group (84 ± 22 vs 73 ± 15 min, p = 0.001) and cost an additional USD 850 per operation. There were no significant differences in clinical outcomes or satisfaction rates at 6 months post-operatively (p > 0.05).

CONCLUSIONS

CASN improved TKA mechanical alignment and component positioning, however, resulted in longer and costlier surgery with no benefits in short-term functional outcomes, despite providing familiarity to surgeons accustomed to conventional instrumentation.

LEVEL OF EVIDENCE

III.