Preoperative phenotype has no significant impact on the clinical outcomes and long-term survival of mechanically aligned total knee arthroplasty in Asian patients with osteoarthritis.

Aims: The aim of this study was to investigate the distribution of phenotypes in Asian patients with end-stage osteoarthritis (OA) and assess whether the phenotype affected the clinical outcome and survival of mechanically aligned total knee arthroplasty (TKA). We also compared the survival of the group in which the phenotype unintentionally remained unchanged with those in which it was corrected to neutral. Methods: The study involved 945 TKAs, which were performed in 641 patients with primary OA, between January 2000 and January 2009. These were classified into 12 phenotypes based on the combined assessment of four categories of the arithmetic hip-knee-ankle angle and three categories of actual joint line obliquity. The rates of survival were analyzed using Kaplan-Meier methods and the log-rank test. The Hospital for Special Surgery score and survival of each phenotype were compared with those of the reference phenotype with neutral alignment and a parallel joint line. We also compared long-term survival between the unchanged phenotype group and the corrected to neutral alignment-parallel joint line group in patients with Type IV-b (mild to moderate varus alignment-parallel joint line) phenotype. Results: The most common phenotype was Type I-b (mild to moderate varus alignment-medial joint line; 27.1% (n = 256)), followed by Type IV-b (23.2%; n = 219). There was no significant difference in the clinical outcomes and long-term survival between the groups. In Type IV-b phenotypes, the neutrally corrected group showed higher 15-year survival compared with the unchanged-phenotype group (94.9% (95% confidence interval (CI) 92.0 to 97.8) vs 74.2% (95% CI 98.0 to 100); p = 0.020). Conclusion: Constitutional varus was confirmed in more than half of these patients. Mechanically aligned TKA can achieve consistent clinical outcomes and long-term survival, regardless of the patient's phenotype. The neutrally corrected group had better long-term survival compared with the unchanged phenotype group.

Limb length change after total knee arthroplasty for valgus deformity does not affect the clinical score and is not affected by fixed flexion deformity.

BACKGROUND: The limb length change (LLC) after total knee arthroplasty (TKA) is especially significant in valgus deformity. The higher LLC could cause higher incidences of lower limb length discrepancy (LLD) and low clinical score. However, studies about LLC after TKA for valgus deformity are limited, and there are none on the relationship between LLC and fixed flexion deformity (FFD) in valgus deformity. HYPOTHESIS: (1) The amount of LLC would affect the postoperative LLD, (2) the improvement of fixed flexion deformity (FFD) would affect the amount of LLC, (3) The amount of LLC would affect the improvement in the clinical score after TKA for valgus deformity. PATIENTS AND METHODS: Fifty knees of 50 patients who underwent primary unilateral TKA for valgus-type osteoarthritis between January 2000 and October 2021 were included. A radiological and clinical assessment were performed the day before the operation and at 12 months post-operatively. Full-length standing anteroposterior radiographs were used to measure HKA and LLC. FFD and Hospital for Special Surgery (HSS) score were measured in the outpatient department. RESULTS: The incidence of lengthening was 92.0% and the mean LLC was 18.85mm (SD, 19.60mm). Postoperative LLD over 10mm occurred in 26% and the mean of postoperative LLD was 4.21mm (SD, 7.96mm). The LLC was correlated with postoperative LLD (rs=0.357, p=0.011) and the HKA change (rs=0.375, p=0.007), but not with the FFD improvement (rs=0.164, p=0.255) and HSS improvement (rs=0.076, p=0.613) or postoperative HSS (rs=0.094, p=0.528). CONCLUSION: LLC was affected by HKA improvement but not by FFD improvement after TKA for patients with valgus deformity. Additionally, LLC did not affect the clinical score. LEVEL OF EVIDENCE: III; retrospective cohort study.

Survivorship After Lateral Meniscal Allograft Transplantation Plus Concurrent Cartilage Procedure in Patients With Poor Cartilage Status: A Comparative Study.

BACKGROUND: The effect of a concurrent cartilage procedure in lateral meniscal allograft transplantation (MAT) in patients with bipolar cartilage lesions (high-grade lesions on both the femoral and the tibial side) is not well studied. An objective evaluation of graft status after MAT and a concurrent cartilage procedure has not been reported. PURPOSE: To investigate the effect of concurrent cartilage procedures and lateral MAT on objective and clinical outcomes, including survival, in patients with bipolar cartilage lesions. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: A total of 149 patients with high-grade (International Cartilage Regeneration & Joint Preservation Society grade 3 or 4) cartilage lesions were enrolled and assigned to 1 of 3 groups based on the cartilage procedure and cartilage status at the time of MAT. Femoral cartilage procedures (microfracture, n = 18; osteochondral autograft transfer, n = 13) and lateral MAT were performed in 31 patients with bipolar cartilage lesions (cartilage procedure group). Another 70 patients with bipolar lesions underwent only lateral MAT without cartilage procedure (bipolar lesion group). The remaining 48 patients, who had high-grade lesions only on the tibial side and underwent lateral MAT without a cartilage procedure, were selected as a control group (unipolar lesion group). Anatomic survival was objectively assessed by follow-up magnetic resonance imaging and second-look arthroscopy. Clinical survivorship was determined with a Lysholm score <65 or need for additional surgery, such as revision MAT. RESULTS: The mean Lysholm score improved from 67.2 ± 15.9 preoperatively to 86.7 ± 11.1 with a mean follow-up of 78.0 ± 51.2 months (P < .001). The postoperative scores were not significantly different between the 3 groups. The estimated 5-year anatomic survival rate in the cartilage procedure group (86.7%) was higher than that in the bipolar lesion group (65.0%; P = .043) but comparable with that in the unipolar lesion group (90.2%; P = .572). The estimated 5-year clinical survival rates were not significantly different between the groups (P = .187). CONCLUSION: A concurrent femoral cartilage procedure improved the anatomic survival rate in patients with bipolar chondral lesions who underwent lateral MAT. This finding suggests that the cartilage procedure is an effective treatment choice and may improve the status of an allograft after lateral MAT for patients with bipolar cartilage lesions.

Effect of High Body Mass Index on Survivorship After Lateral Meniscal Allograft Transplantation: A Propensity Score Matching Analysis.

BACKGROUND: Preoperative body mass index (BMI) is one of the correctable factors before surgery. Few studies have investigated the effect of BMI on the survivorship of lateral meniscal allograft transplantation (MAT). HYPOTHESIS: Patients with a high BMI have inferior survivorship after lateral MAT when compared with those with a normal BMI. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Overall, 306 consecutive patients who underwent lateral MAT were retrospectively reviewed. According to the classification criteria of the World Health Organization, patients were split into 2 groups: normal weight (BMI <25.0) and overweight (BMI ≥25.0). There were 104 patients (34.0%) allocated into the overweight group. Given the demographic heterogeneity between the groups, propensity score matching was performed. Before and after propensity score matching, the anatomic and clinical survival rates of the 2 groups were compared by Kaplan-Meier survival analysis. Anatomic failure was defined as a tear covering >50% of the allograft or unstable peripheral rim on follow-up magnetic resonance imaging and second-look arthroscopy. Clinical failure was defined as a Lysholm score <65 or need for additional surgery, such as revision MAT. RESULTS: For all patients, the mean ± SD follow-up period was 6.9 ± 4.2 years. The mean BMI of the overweight and normal weight groups was 27.8 ± 2.6 and 22.0 ± 1.9, respectively. The mean Lysholm scores at the last follow-up were not significantly different between the groups. However, the anatomic survival rate in the overweight group (77.9%) was significantly lower than that in the normal weight group (90.1%) (P < .001). The clinical survival rate (82.7%) in the overweight group was significantly lower than that in the normal weight group (95.0%) (P < .001). After propensity score matching for patient characteristics, which left 87 patients per group, the anatomic and clinical survival rates were significantly lower in the overweight group. CONCLUSION: Preoperative high BMI was associated with inferior anatomic and clinical survival rates. The results of the current study suggest that weight loss before lateral MAT may be required in overweight patients for the improvement of anatomic and clinical survival rates.