Bum-Sik Lee

Femoral Component Varus Malposition is Associated with Tibial Aseptic Loosening After TKA

Background The notion that neutral alignment is mandatory to assure long-term durability after TKA has been based mostly on short-film studies. However, this is challenged by recent long-film studies. Questions/purposes We conducted this long-film study to know (1) whether the risk of aseptic revision for nontraumatic reasons was greater among knees with greater than 3° varus or valgus (defined as “outliers”) than those that were aligned within 3° of neutral on long-standing mechanical axis (hip to knee) radiographs; and (2) what the failure mechanisms were and whether the malalignment was femoral or tibial in origin, or both, among those in the outlier group. Methods Between November 1998 and January 2009 we performed 1299 cemented, posterior cruciate ligament-substituting TKAs in 867 patients for primary osteoarthritis. We had inadequate long-standing radiographs to analyze postoperative alignment for 124 of those knees, and an additional 24 were excluded for prespecified reasons. Consequently, 1151 knees were enrolled in our study. Of these, 982 (85%) in 661 patients (620 women and 41 men) who had followup greater than 24 months were analyzed. The knees were divided according to whether the postoperative mechanical axis was neutral (0° ± 3°), varus (> 3°), or valgus (< -3°) alignment on long-standing radiographs. The survivorships free from aseptic revision for nontraumatic reasons were compared among groups. The mechanical femoral and the tibial component alignment (MFCA and MTCA, respectively) were investigated to know the origin of overall mechanical malalignment of the outlier knees. The mean duration of followup was 8 ± 4 years (range, 2–17 years). Thirty-five knees (4%) showed aseptic loosening at 7 ± 4 years (range, 0.1–14 years) and five (1%) showed polyethylene wear at 12 ± 1 years (range, 10-13 years). Tibial loosening (73%) was the most common reason for aseptic revision followed by femoral loosening (30%). Of this cohort, 687 (70%), 250 (25%), and 45 (5%) knees had overall mechanical neutral, varus, and valgus alignment, respectively. Factors associated with the risk of aseptic revision were identified by Cox regression. Results The varus outliers (but not the valgus outliers) failed more often than the neutral knees (10% [25 of 250] versus 2% [13 of 687]; odds ratio [OR], 5.8, 95% CI, 2.9–11.5; p < 0.001). Ten-year survivorship free from aseptic revision was lower among varus outliers than among knees with neutral alignment (87% [95% CI, 80%–93%] versus 98% [95% CI, 97%–99%]; p = 0.001). Femoral component varus malpositioning was the main origin of the varus outliers (MFCA = 4.2° ± 2.0°; MTCA = 0.9° ± 1.7°) and was a risk factor for aseptic revision compared with neutral femoral positioning (OR, 14.0; 95% CI, 1.9–105.6; p < 0.001). Conclusions This long-film study corresponds to previous short-film studies for the notion that varus malalignment is associated with inferior long-term implant survivorship. Although aseptic loosening occurred most commonly on the tibial side, the primary origin of the overall varus malalignment was femoral component varus malpositioning. Aiming for neutral alignment in TKA still seems to be a reasonable strategy in clinical practice. Level of Evidence Level III, therapeutic study.

Clinical Outcomes of Meniscal Allograft Transplantation With or Without Other Procedures: A Systematic Review and Meta-analysis:

Background: While additional procedures correcting accompanying pathological conditions can improve the clinical outcomes of meniscal allograft transplantation (MAT), whether those outcomes are comparable or poorer than those of isolated MAT has yet to be clarified. Purpose:  To evaluate whether there is a difference in clinical outcomes between isolated MAT and MAT combined with other procedures (combined MAT). Study Design: Meta-analysis and systematic review. Methods: For the comparison of clinical outcomes between isolated MAT and combined MAT, the authors searched MEDLINE, Embase, and the Cochrane Library. Studies that separately reported the clinical outcomes of isolated MAT and combined MAT were included. Clinical outcomes were evaluated in terms of patient-reported outcomes (PROs) and complication, reoperation, survivorship, and failure rates. We conducted a meta-analysis of the PROs that were used in more than 3 studies. Results: A total of 24 studies were included in this study. In the meta-analysis, no significant differences in Lysholm scores (95% CI, –5.92 to 1.55; P = .25), Tegner activity scores (95% CI, –0.54 to 0.22; P = .41), International Knee Documentation Committee subjective scores (95% CI, –5.67 to 3.37; P = .62), and visual analog scale scores (95% CI, –0.15 to 0.94; P = .16) were observed between isolated MAT and combined MAT. For PROs that were not included in the meta-analysis, most studies reported no significant difference between the 2 groups. As for the survivorship and failure rates, studies showed varying outcomes. Four studies reported that additional procedures did not affect MAT failure or survivorship. However, 3 studies reported that ligament surgery, realignment osteotomy, and osteochondral autograft transfer were risk factors of failure. One study reported that the medial MAT group in which high tibial osteotomy was performed showed a higher survival rate than the isolated medial MAT group. Conclusion: Overall, there seems to be no significant difference between the postoperative PROs in terms of isolated MAT and combined MAT. However, more data are required to verify the effects of osteotomy and cartilage procedures on the clinical outcomes of MAT. We could not draw conclusions about the differences in complication, reoperation, survivorship, and failure rates between the 2 groups because we did not obtain sufficient data.

Editorial Commentary: Meniscal Allograft Transplantation: Still Effective With Poor Cartilage, But Much Better With Good Cartilage—Better Done Earlier

Meniscal allograft transplantation (MAT) is an established treatment for a symptomatic, meniscus-deficient knee. It is well known that MAT is effective in patients with good cartilage even in the early era of this procedure. The role of MAT in arthritic knees is getting more and more clear with increasing evidence over the last decade. Now we are able to expand our surgical indication to arthritic patients and provide them with individualized explanation for outcome and survival.

Comparison of patellar tracking according to different angles of external rotation of femoral component in varus knee of Asians

Purpose: Racial difference in the femoral geometry may exist. Asian femurs may be more externally rotated. If anatomical differences in distal femur had existed between Caucasians and Asians, the group with 5° external rotation of the femoral component should have shown better results than the group with 3° external rotation of the femoral component have. Methods: 598 patients underwent total knee arthroplasty in our institution, among whom 83 patients (115 knees) who had postoperative computed tomography (CT) were studied retrospectively. Sixty-two knees were set in 5° of external rotation of femoral component relative to the posterior condylar axis (group A) while the others (53 knees) were set in 3° (group B). The femoral component rotation (FCR) was measured and compared using CT. The patellar tilting (PT) and the lateral patellar displacement (LPD) were measured to evaluate the patellar tracking using Merchant view. And postoperative clinical scores were compared. Results: The mean FCRs showed no significant difference between two groups (p > 0.05). The mean PT and LPD showed no statistically significant difference either (p > 0.05). There were no statistical differences in clinical scores. Conclusion: The difference in the patellar tracking between the two groups could not be demonstrated. There were no statistical differences in clinical scores either. We concluded there is no need to adhere to 5° external rotation.