The goal of successful total knee arthroplasty (TKA) has been to restore the mechanical alignment of the lower limb, because incorrect alignment can lead to abnormal prosthesis wear, and premature mechanical loosening (1-3). Many previous studies reported that postoperative malalignment of >3° from the mechanical axis, particularly into varus angulation, can lead to early failure in TKA (1,2,4,5), although this topic has become a debated topic recently (6).
Despite a lack of conclusive evidence for the appropriate postoperative alignment, the computer-assisted surgical (CAS) navigation system was designed to obtain more reliable and reproducible intraoperative alignment than conventional TKA (7-12). In general, CAS navigation can be categorized into three groups: image-based or imageless large-console navigation and handheld navigation. The disadvantages of large-console navigation systems are that they require transosseous tracker pins in the femur and tibia, appropriate optical tracking in a complicated surgical setting, and prolonged operative time with long learning curve periods (13,14). To address these limitations, the handheld navigation systems were introduced with the advantages of shorter learning curve periods, no transosseous tracker pins, no need to ream the femoral/tibial canal, no optical tracking which might be affected by conditions in the operating room, and similar instrumentation to conventional TKAs. Xu et al. (15) reported the results of TKA using a novel handheld accelerometer-based navigation system called i-JOIN. Alike the results of previous different kind of handheld navigation systems (16-20), the coronal femur alignments in this handheld navigation were not significantly different compared to that of a conventional system, although the postoperative mechanical axis seemed to be close to neutral alignment and the number of outliers more than 3° were found less frequently in the handheld navigation group. However, the surgical time in a study by Xu et al. (15) was still longer in a handheld navigation group than a conventional group, and it was similar to the results of a recent meta-analysis (16). Hence, there are still limitations including increased surgical time, lack of information for soft tissue balancing and rotational alignment, and lack of cost-effectiveness in terms of clinical outcomes when using a handheld navigation system (16). However, the surgical time might be shorter than that of the TKA using large-console navigation system, which needs transosseous tracker pins, it would be interesting to compare the clinical results between large-console navigation and hand held navigation system in further study. Finally, further studies are also warranted because it is likely that technology will continue to improve, including introducing handheld robot assisted TKA (21-23).
Conflicts of Interest: The authors have no conflicts of interest to declare.
Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.
Open Access Statement: This is an Open Access article distributed in accordance with the Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International License (CC BY-NC-ND 4.0), which permits the non-commercial replication and distribution of the article with the strict proviso that no changes or edits are made and the original work is properly cited (including links to both the formal publication through the relevant DOI and the license). See: https://creativecommons.org/licenses/by-nc-nd/4.0/.
- Sikorski JM. Alignment in total knee replacement. J Bone Joint Surg Br 2008;90:1121-7. [Crossref] [PubMed]
- Sikorski JM. Computer-assisted total knee replacement. J Bone Joint Surg Br 2005;87:1164. [Crossref] [PubMed]
- Song SJ, Park CH, Bae DK. What to Know for Selecting Cruciate-Retaining or Posterior-Stabilized Total Knee Arthroplasty. Clin Orthop Surg 2019;11:142-50. [Crossref] [PubMed]
- Lombardi AV Jr, Berend KR, Ng VY. Neutral mechanical alignment: a requirement for successful TKA: affirms. Orthopedics 2011;34:e504-6. [PubMed]
- Berend ME, Ritter MA, Meding JB, et al. Tibial component failure mechanisms in total knee arthroplasty. Clin Orthop Relat Res 2004.26-34. [Crossref] [PubMed]
- Parratte S, Pagnano MW, Trousdale RT, et al. Effect of postoperative mechanical axis alignment on the fifteen-year survival of modern, cemented total knee replacements. J Bone Joint Surg Am 2010;92:2143-9. [Crossref] [PubMed]
- Keyes BJ, Markel DC, Meneghini RM. Evaluation of limb alignment, component positioning, and function in primary total knee arthroplasty using a pinless navigation technique compared with conventional methods. J Knee Surg 2013;26:127-32. [PubMed]
- Bäthis H, Perlick L, Tingart M, et al. Alignment in total knee arthroplasty. A comparison of computer-assisted surgery with the conventional technique. J Bone Joint Surg Br 2004;86:682-7. [Crossref] [PubMed]
- Kim SH, Park YB, Song MK, et al. Reliability and Validity of the Femorotibial Mechanical Axis Angle in Primary Total Knee Arthroplasty: Navigation versus Weight Bearing or Supine Whole Leg Radiographs. Knee Surg Relat Res 2018;30:326-33. [Crossref] [PubMed]
- Kim SH, Park YB, Ham DW, et al. No influence of femoral component rotation by the lateral femoral posterior condylar cartilage remnant technique on clinical outcomes in navigation-assisted TKA. Knee Surg Sports Traumatol Arthrosc 2017;25:3576-84. [Crossref] [PubMed]
- Kim SH, Lee HJ, Jung HJ, et al. Less femoral lift-off and better femoral alignment in TKA using computer-assisted surgery. Knee Surg Sports Traumatol Arthrosc 2013;21:2255-62. [Crossref] [PubMed]
- Kim SH, Lim JW, Ko YB, et al. Comparison of ultra-congruent mobile- and fixed-bearing navigation-assisted total knee arthroplasty with minimum 5-year follow-up. Knee Surg Sports Traumatol Arthrosc 2016;24:3466-73. [Crossref] [PubMed]
- Jones CW, Jerabek SA. Current Role of Computer Navigation in Total Knee Arthroplasty. J Arthroplasty 2018;33:1989-93. [Crossref] [PubMed]
- Matsumoto T, Nakano N, Lawrence JE, et al. Current concepts and future perspectives in computer-assisted navigated total knee replacement. Int Orthop 2019;43:1337-43. [Crossref] [PubMed]
- Xu X, Liu P, Yuan Z, et al. 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. Ann Transl Med 2019;7:659. [Crossref] [PubMed]
- Li JT, Gao X, Li X. Comparison of iASSIST Navigation System with Conventional Techniques in Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of Radiographic and Clinical Outcomes. Orthop Surg 2019;11:985-93. [Crossref] [PubMed]
- Kinney MC, Cidambi KR, Severns DL, et al. Comparison of the iAssist Handheld Guidance System to Conventional Instruments for Mechanical Axis Restoration in Total Knee Arthroplasty. J Arthroplasty 2018;33:61-6. [Crossref] [PubMed]
- Huang EH, Copp SN, Bugbee WD. Accuracy of A Handheld Accelerometer-Based Navigation System for Femoral and Tibial Resection in Total Knee Arthroplasty. J Arthroplasty 2015;30:1906-10. [Crossref] [PubMed]
- Iorio R, Mazza D, Drogo P, et al. Clinical and radiographic outcomes of an accelerometer-based system for the tibial resection in total knee arthroplasty. Int Orthop 2015;39:461-6. [Crossref] [PubMed]
- Bugbee WD, Kermanshahi AY, Munro MM, et al. Accuracy of a hand-held surgical navigation system for tibial resection in total knee arthroplasty. Knee 2014;21:1225-8. [Crossref] [PubMed]
- Casper M, Mitra R, Khare R, et al. Accuracy assessment of a novel image-free handheld robot for Total Knee Arthroplasty in a cadaveric study. Comput Assist Surg (Abingdon) 2018;23:14-20. [Crossref] [PubMed]
- Khare R, Jaramaz B, Hamlin B, Urish KL. Implant orientation accuracy of a hand-held robotic partial knee replacement system over conventional technique in a cadaveric test. Comput Assist Surg (Abingdon) 2018;23:8-13. [Crossref] [PubMed]
- Lonner JH, Smith JR, Picard F, et al. High degree of accuracy of a novel image-free handheld robot for unicondylar knee arthroplasty in a cadaveric study. Clin Orthop Relat Res 2015;473:206-12. [Crossref] [PubMed]