Using the Anatomical Axis as an Alternative to the Mechanical Axis to Assess Knee Alignment

Tipton, Shane; Sutherland, John K.; Schwarzkopf, Ran

doi:10.3928/01477447-20151123-01

Cited by 10 publications

(5 citation statements)

References 15 publications

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“…The anatomic angle of the femur is 5.5 in the current is study, which is consistent with reports in the literature (5 −7 ) 28,29 . Therefore, the reliability of the current study should be high.…”

Section: Measurement Of the Q-angle On A Full-length Standing Scanogramsupporting

confidence: 92%

Imaging Approaches for Accurate Determination of the Quadriceps Angle

Yeow

2020

Orthopaedic Surgery

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Objectives A retrospective study was conducted using magnetic resonance image (MRI) and a full‐length standing scanogram (FLSS) to measure the quadriceps angle (Q‐angle) while avoiding soft tissue interference. Methods Two steps were retrospectively carried out in two case series. The first step involved using MRI to define the standardized patellar center (PC) and the tibial tubercle (TT) on the frontal plane of the MRI in one group of 60 consecutive patients (from July 2016 to December 2016, 29 men and 31 women, average of 46 years). The next step was transferring the location of the standardized PC and the TT from the MRI to the FLSS in another group of 100 consecutive patients (from April 2009 to March 2014, 50 men and 50 women, average of 36 years). The pelvis and intact femur, knee, and tibia were used to determine the Q‐angle on the FLSS. Results The standardized PC was positioned 42% from the lateral end of femur trans‐epicondylar line. The TT was 2 cm distal to the tibial articular surface and 37% from the lateral end of tibial width. The average Q‐angle was 9.5° in 100 patients (8.8° in 50 men and 10.1° in 50 women, P = 0.02). The average femoral length was 42.9 cm in 100 patients (44.7 cm in 50 men and 41.1 cm in 50 women, P < 0.001). Women and men had similar pelvic width (27.9 vs 27.8 cm, P = 0.89). Conclusion Using the FLSS may help to accurately determine the Q‐angle. Men and women have similar pelvic width. A larger Q‐angle in women may be mainly due to the shorter femur.

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Section: Measurement Of the Q-angle On A Full-length Standing Scanogramsupporting

confidence: 92%

Imaging Approaches for Accurate Determination of the Quadriceps Angle

Yeow

2020

Orthopaedic Surgery

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“…Although each was evaluated for quality, radiographic measurements were based on anatomic axis as opposed to mechanical axis measurements from formal hip-knee-ankle radiographs. However, the use of anatomic axis on limited radiographs has been validated as an estimate of full-length films [15] . In addition, while the average time to diagnosis was approximately 6 months, it is difficult to identify more specifically when this process first occurs based on the standard timing of the radiographs.…”

Section: Discussionmentioning

confidence: 99%

Proximal tibial resorption in a modern total knee prosthesis

et al. 2018

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BackgroundIn an effort to minimize backside polyethylene wear and osteolysis associated with titanium tibial baseplates, many manufacturers have transitioned to cobalt chromium alloys. Recent literature has implicated thicker cobalt chromium designs as a potential source of increased stress shielding and resorption. We report the incidence of proximal tibial bone resorption in a large consecutive series of patients undergoing total knee arthroplasty, with a modern total knee design.MethodsFour hundred thirty-two consecutive primary total knee arthroplasties, performed by 2 fellowship-trained arthroplasty surgeons were identified over a 24-month period. In addition to review of the medical records, analysis of preoperative and postoperative radiographs was performed. Utilizing a novel classification system, the severity of resorption was quantified and correlated with patient and implant characteristics.ResultsAfter exclusions, 339 knees were evaluated in 292 patients. Mean follow-up was 13.2 months (range 6-41). Resorption was present in 119 knees (35.1%). Average time to diagnosis of bone loss was 6.9 months (range 2-32) postoperatively. There was a statistically significant difference between resorption and nonresorption groups with regards to gender and preoperative alignment. Most cases were classified as Grade 1. During the study period, 2 patients required revision for aseptic tibial loosening.ConclusionsOur findings suggest that proximal tibial resorption is common with this particular implant, particularly in men and patients with preoperative varus deformity. Although this typically occurs relatively early in postoperative period and in most cases appears to remodel and stabilize, its ultimate clinical significance and effect on implant survivorship remains unclear.

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“…The angle between the femoral and tibial mechanical axes was measured as the mechanical axis (MA) pre-and postoperatively (Figure 2A). 20,21 In addition, the authors estimated femoral and tibial bowing on coronal plain radiographs using Yau's method. 3 Bowing of greater than 3° was defined as marked femoral or tibial bowing ( Figure 2B).…”

Section: Methodsmentioning

confidence: 99%

Using Accelerometer-Based Portable Navigation to Perform Accurate Total Knee Arthroplasty Bone Resection in Asian Patients

Ueyama¹,

Matsui²,

Minoda³

et al. 2017

Orthopedics

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Implant alignment is an important factor affecting clinical results associated with total knee arthroplasty (TKA). No report exists showing the utility of an accelerometer-based portable navigation system among patients with marked femoral bowing. The aim of this study was to evaluate the accuracy of a portable navigation system for implant alignment in Asian patients with marked femoral bowing. The authors evaluated 142 consecutive TKAs performed for primary osteoarthritis since July 2013. A portable navigation system was used in 67 knees, and a conventional jig was used in 75 knees. The authors measured the mechanical axis and femoral/tibial component alignments on long-leg radiographs obtained 2 weeks after TKA. In addition, coronal bowing of the lower limb was evaluated. The results were analyzed in the general and marked femoral bowing subgroups. There were no significant differences between the 2 groups for demographic data. The rates of femoral component outliers in the coronal plane for the navigation system and conventional technique were 1.5% and 13.3% (P=.01), respectively. Marked femoral bowing was observed in 73 knees. In the subgroup of patients with marked femoral bowing, femoral coronal alignment and its outliers were more accurate in the navigation group (0%) than in the conventional group (16.2%) (P=.025). This is the first report to show the utility of an accelerometer-based portable navigation system for accurate prosthetic alignment among Asian patients with marked femoral bowing. The navigation system decreased outliers in coronal alignment of the femur, even in cases of marked femoral bowing, but did not increase complications. [Orthopedics. 2017; 40(3):e465-e472.].

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Using the Anatomical Axis as an Alternative to the Mechanical Axis to Assess Knee Alignment

Cited by 10 publications

References 15 publications

Imaging Approaches for Accurate Determination of the Quadriceps Angle

Imaging Approaches for Accurate Determination of the Quadriceps Angle

Proximal tibial resorption in a modern total knee prosthesis

Using Accelerometer-Based Portable Navigation to Perform Accurate Total Knee Arthroplasty Bone Resection in Asian Patients

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