Decreased Femoral Trochlear Length Associated With Increased Anterior Knee Pain Following Total Knee Arthroplasty: A New Anatomical Perspective.

BACKGROUND: Anterior knee pain (AKP) and patello-femoral crepitus (PFCr) continue to plague total knee arthroplasty patients despite advances and modifications to implant design and surgical techniques. We present our study of the femoral trochlear length measurement preimplantation and postimplantation and its association with AKP/PFCr and clinical scores. METHODS: Using computer navigation, we obtained several measurements in 263 total knee arthroplasty (posterior-stabilized) patients, which included femoral native trochlear measurement (NTM) and difference in trochlear length between implant and native trochlea. We report their association with Knee Society Score, Western Ontario McMaster University Arthritic Index, and AKP/PFCr at 1 year postoperatively. RESULTS: Mean Knee Society Score and Western Ontario McMaster University Arthritic Index scores were significantly worse in patients who had AKP (P = .005 and P = .002 respectively). Receiver operating characteristic curve showed a statistically significant association between NTM and AKP (Area under the curve = 0.609, P = .014). Lower the NTM, greater was the incidence of AKP. Analysis of the receiver operating characteristic curve identified the cutoff value of NTM to be ≤25.5 with sensitivity of 76.7(95% confidence interval - 57.7 - 90.1) and specificity of 46.9 (95% confidence interval - 41.9 - 55.1). Patients who had NTM of ≤25.5 had an odds ratio of 3.09 to have AKP. The difference in trochlear length ranged from 7.4 to 32.1 millimeters, indicating that postimplantation there was lengthwise overstuffing along the trochlea in every patient. CONCLUSION: We found that the shorter the native femoral trochlea and greater the difference between implanted and native trochlea, the higher was the occurrence of AKP. A mismatch in trochlear measurement preimplantation and postimplantation resulted in lengthwise overstuffing in the anterior knee causing AKP and PFCr.

Comparison of Patellofemoral Outcomes between Attune and PFC Sigma Designs: A Prospective Matched-Pair Analysis.

BACKGROUD: Attune (DePuy Synthes) prosthesis was designed to overcome patellofemoral complications associated with PFC Sigma (DePuy Synthes) prosthesis. The aim of our study was to compare the incidence of anterior knee pain (AKP), patellofemoral crepitus (PCr), and functional outcome between them. METHODS: This prospective matched-pair study was conducted between January 2014 and June 2015, during which 75 consecutive Attune total knee arthroplasties (TKAs) were matched with 75 PFC Sigma TKAs based on age, sex, body mass index, pathology, and deformity. A single surgeon performed all the operations with aid of computer navigation, using a posterior-stabilized prosthesis with patellar resurfacing. Outcome was assessed by new Knee Society Score (NKSS) and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score. AKP and PCr were assessed by a patient-administered questionnaire till 2 years of follow-up. Three pairs were lost to follow-up and finally 72 pairs were analyzed. RESULTS: One patient in each group reported AKP and 1 patient from each group had PCr at 2 years postoperatively. None of these patients required additional surgery. The incidence of lateral retinacular release was higher with PFC Sigma (5/72) than Attune (2/72); however, this was statistically not significant (p = 0.4). The Attune group had a significantly greater range of motion (ROM) at 3 months postoperatively (p = 0.049). At final follow-up, ROM was comparable between two prosthesis designs. NKSS and WOMAC scores were also comparable between the groups. CONCLUSIONS: We observed that both Attune and PFC Sigma had a low and comparable incidence of AKP and PCr up to 2 years of follow-up. The Attune group achieved a significantly greater ROM at 3 months postoperatively. At 2 years of follow-up, both prostheses had excellent and comparable clinical and functional results.

Does Postoperative Intravenous Ferric Carboxymaltose Hasten the Recovery of Hemoglobin in Patients Post Total Knee Arthroplasty?

BACKGROUND: Timely and effective iron supplementation may help reduce the incidence of postoperative anemia and its associated problems. In this study, we aim to assess the efficacy of intravenous ferric carboxy maltose (FCM) on improving hemoglobin(Hb) level posttotal knee arthroplasty (TKA). METHODS: We retrospectively reviewed 263 patients who had undergone unilateral TKA with 157 patients in the study group (year 2019) and 106 in the control group (year 2016). Patients in the study group received FCM (500 mg IV) on postoperative day 1, whereas patients in the control group did not receive FCM or any other iron supplementation postoperatively. Hb levels were recorded preoperatively (Pr-Hb), postoperatively on day 3 (Day3-Hb) and postoperatively at 5(+1) weeks (Week5-Hb). Statistical analysis was performed using student's paired and unpaired t-tests. RESULTS: Pr-Hb and Day3-Hb levels were comparable in the control and study group, while Week5-Hb levels were significantly higher (P < .001) in the study group. The drop in Hb at Day3 from preoperative values was comparable between the two groups (P = 1.0). The rise in Hb from Day3 to 5 weeks was significantly higher in the study group as compared to the control group (P < .001). The difference between Pr-Hb and Week5-Hb was significantly lower (P < .001) in the study group compared to the control group. However, Week5-Hb in both groups remained lower than Pr-Hb (P < .001) in all patients. CONCLUSION: Intravenous FCM (500 mg) was found to be a safe method of iron supplementation to improve hemoglobin levels rapidly and consistently, post-TKA. We need to further study the additive effect of higher dose FCM (1000 mg) on hemoglobin recovery.