Relationship between knee alignment and radiographic markers of osteoarthritis: a cross-sectional study from a Korean population

Outcomes of cruciate-retaining total knee arthroplasty for osteoarthritis with severe varus deformity

BACKGROUND

Varus deformity is common in osteoarthritic knee. The purpose of this study was to investigate the clinical and radiographic outcomes after cruciate-retaining (CR) total knee arthroplasty (TKA) for severely varus osteoarthritic knees and compare them to those of mildly to moderately deformed osteoarthritic knees.

METHODS

Eight hundred ninety-four subjects were undergone CR TKA, 137 had severe varus deformity (group 1), and 757 had mild-to-moderate deformity (group 2) of the lower limb preoperatively. Pre- and postoperative outcomes were compared between two groups clinically and radiographically.

RESULTS

Mean follow-up period was 54.7 ± 28.9 months. Mean age was 77.8 ± 6.7 years in group 1 and 74.5 ± 7.4 years in group 2 (p < 0.001). Preoperative hip-knee-ankle angle (HKAA) was - 17.7°±2.9° in group 1 and - 6.3° ± 5.1° in group 2 (p < 0.001). Preoperative range of motion (ROM) was 127.7° ± 15.2° in group 1 and 130.8 °± 9.6° in group 2 (p = 0.019). Preoperative Knee Society scores and WOMAC score were not significantly different between two groups. Postoperative HKAA was - 0.4° ± 2.3° in group 1 and 0.6 ° ± 2.0° in group 2 (p < 0.001). Postoperative ROM, Knee Society scores, and WOMAC score were not significantly different between two groups.

CONCLUSIONS

CR TKA showed results in subjects with severe varus deformities comparable to those without severe varus deformities. Whether the degree of preoperative varus deformity of the lower limb should be considered when deciding to perform CR-type or PS-type TKA requires further discussion.

LEVEL OF EVIDENCE

Retrospective comparative study, Level III.

The association of frontal plane alignment to MRI-defined worsening of patellofemoral osteoarthritis: the MOST study

OBJECTIVE

To determine the sex-specific relation of frontal plane alignment (FPA) to magnetic resonance imaging (MRI)-defined features of patellofemoral osteoarthritis, and also to tibiofemoral osteoarthritis and knee pain.

METHOD

The Multicenter Osteoarthritis Study is cohort study comprised of individuals with or at risk of knee osteoarthritis. We determined the sex-specific dose-response relation of baseline FPA to MRI-defined patellofemoral and tibiofemoral structural worsening, and incident knee pain, over 7 years.

RESULTS

In women only, greater varus alignment was associated with medial patellofemoral osteophytes (risk ratio [RR] 1.7 [95% CI 1.2, 2.6]) and valgus with lateral patellofemoral osteophytes (RR 1.9 [1.0, 3.6]). In men, greater varus increased risk for medial tibiofemoral cartilage worsening (RR 1.7 [1.1, 2.6]), and valgus for lateral tibiofemoral cartilage worsening (RR 1.8 [1.6, 2.2]). In women, findings were similar for tibiofemoral cartilage, but varus also increased risk for medial bone marrow lesions [BMLs] (RR 2.2 [1.6, 3.1]) and medial osteophytes (RR 1.8 [1.3, 2.5]), and valgus for lateral BMLs (RR 3.3 [2.2, 4.5]) and osteophytes (RR 2.0 [1.2, 3.2]). Varus increased risk of incident pain in men (RR 1.7 [1.4, 2.2]) and women (RR 1.3 [1.0, 1.6]), valgus did so in men only (RR 1.5 [1.1, 1.9]).

CONCLUSION

FPA was associated with patellofemoral osteophyte worsening in women, though overall was more strongly associated with tibiofemoral than patellofemoral osteoarthritis feature worsening. FPA in women was more consistently associated with structural worsening, yet men had higher associations with incident pain.