Correlation of radiographic and navigated measurements of TKA limb alignment: a matter of time?
Valid and reproducible measurements of limb alignment are prerequisites for planning, performing and evaluating TKAs. Although navigation systems have been shown to be reproducible tool for intraoperative TKA alignment measurements, particular doubt has been raised on the correlation with postoperative radiographic measurements. The aim of the present study was to evaluate whether the association of postoperative radiographic and navigation measurements of limb alignment was dependent on the time of acquisition. For this purpose, we retrospectively compared two groups of patients who underwent computer-assisted cemented TKA for osteoarthritis of the knee. Intraoperative navigation measurements (OrthoPilot™, Aesculap, Tuttlingen, Germany) were recorded before any cuts were made and again after implants had been placed. Long leg standing radiographs were acquired preoperatively in both the groups and either 2 weeks or 3 months postoperatively and AP limb alignment measurements were correlated with those of the respective navigation assessments. Preoperative deformity was similar in both the groups and correlation between radiographic and navigation measurements was excellent in both groups (ρ = 0.845 and 0.945, respectively). However, both mean and maximum discrepancies between radiographic and navigation measurements of leg alignment were significantly larger when radiographs were obtained 2 weeks (2.6° ± 2.1°, max. 10°) when compared with 3 months (1.8° ± 1.4°, max. 5°) postoperatively (P = 0.026). Accordingly, correlation between radiographic and navigation measurements was poor when radiographs were obtained 2 weeks postoperatively (ρ = 0.26, n.s.) but in the range of preoperative assessments when obtained 3 months postoperatively (ρ = 0.841, P < 0.001). Radiographic and navigation measurements of TKA limb alignment correlate well preoperatively. Equally good correlations can only be achieved when postoperative radiographic measurements are delayed to a time when more patients achieve full or near-full extension and are able to bear full weight leading to more valid radiographs.
Hauschild
Oliver
O
Department of Orthopedic Surgery and Traumatology, Freiburg University Medical Center, Hugstetter Str. 55, 79106 Freiburg, Germany. oliver.hauschild@uniklinik-freiburg.de
Konstantinidis
Lukas
L
Baumann
Tobias
T
Niemeyer
Philipp
P
Suedkamp
Norbert P
NP
Helwig
Peter
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D017760:Bone Malalignment / Q000000981:diagnostic imaging*; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007432:Intraoperative Period; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000000981:diagnostic imaging* / Q000601:surgery*; D011183:Postoperative Complications / Q000503:physiopathology; D011300:Preoperative Care / Q000379:methods; D016059:Range of Motion, Articular / Q000502:physiology*; D020127:Recovery of Function; D012189:Retrospective Studies; D018570:Risk Assessment; D012720:Severity of Illness Index; D025321:Surgery, Computer-Assisted / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
Orthopedics. 2007 Apr;30(4):299-303
17424694
J Bone Joint Surg Br. 1991 Sep;73(5):709-14
1894655
Knee Surg Sports Traumatol Arthrosc. 2009 Oct;17(10):1143-51
19495724
Orthopade. 2006 Oct;35(10):1056-65
16953328
Clin Orthop Relat Res. 1996 Oct;(331):102-6
8895625
Clin Orthop Relat Res. 1994 Dec;(309):136-45
7994952
J Bone Joint Surg Br. 2004 Jul;86(5):682-7
15274263
Am J Sports Med. 2007 Jan;35(1):65-70
16998083
J Arthroplasty. 2007 Dec;22(8):1150-61
18078884
Knee Surg Sports Traumatol Arthrosc. 2008 Mar;16(3):249-57
18157493
J Arthroplasty. 2005 Aug;20(5):591-601
16309994
Clin Orthop Relat Res. 2002 Nov;(404):196-202
12439260
J Bone Joint Surg Br. 2006 Nov;88(11):1513-8
17075100
J Orthop Res. 2008 Apr;26(4):553-61
17972322
Clin Orthop Relat Res. 1994 Feb;(299):153-6
8119010
J Bone Joint Surg Br. 1991 Sep;73(5):715-20
1894656
Eur Radiol. 2005 Jan;15(1):170-3
15300399
J Arthroplasty. 2005 Oct;20(7):832-9
16230232
Int Orthop. 2004 Apr;28(2):87-90
15224165
Clin Orthop Relat Res. 2009 Feb;467(2):504-9
18841432
J Chin Med Assoc. 2004 Apr;67(4):185-8
15244017
Arthritis Rheum. 2006 Apr 15;55(2):306-13
16583430
Comput Aided Surg. 2004;9(4):161-5
16192056
Eur Radiol. 2008 Jul;18(7):1497-505
18351353
Orthop Clin North Am. 1994 Jul;25(3):425-65
8028886
Clin Orthop Relat Res. 1983 Mar;(173):178-83
6825330
J Arthroplasty. 2005 Oct;20(7 Suppl 3):123-31
16214013
J Knee Surg. 2004 Oct;17(4):203-10
15553587
Clin Orthop Relat Res. 2008 Nov;466(11):2736-44
18752032
Osteoarthritis Cartilage. 1997 Jan;5(1):39-47
9010877
J Bone Joint Surg Am. 2008 Jan;90(1):43-51
18171956