Preoperative predictors of implant size in patients undergoing total knee arthroplasty: a retrospective cohort study.

BACKGROUND: Traditionally, the size of total knee arthroplasty (TKA) components is predicted by preoperative radiographic templating, which is of limited accuracy. This study aimed to evaluate the role of demographic data and ankle volume in predicting implant size in TKA candidates. METHODS: In a retrospective study, 415 patients who underwent TKA at a single institution were included. The mean age of the patients was 67.5 ± 7.1 years. The mean BMI of the patients was 31.1 ± 4.7 kg/m2. TKA implants were Zimmer Biomet NexGen LPS-Flex Knee in all cases. The demographic data included age, sex, height, weight, BMI, ethnicity, and ankle volume. Ankle volume was assessed with the figure-of-eight method. Multivariate linear regression analysis was used for predicting factors of implant size. RESULTS: Multivariate linear regression analysis showed that the Sex (ß:1.41, P < 0.001), height (ß:0.058, P < 0.001), ankle volume (ß:0.11, P < 0.001), and Age (ß:0.017, P = 0.004) were significant predictors of tibial component size. Sex (ß:0.89, P < 0.001), height (ß:0.035, P < 0.001), and ankle volume(ß:0.091, P < 0.001) were significant predictors of femoral component size in the multivariate analysis. CONCLUSION: Demographic data, adjunct with the ankle volume, could provide a promising model for preoperative prediction of the size of tibial and femoral components in TKA candidates.

Midterm Outcomes of Unicompartmental Knee Arthroplasty for the Treatment of Knee Medial Compartment Osteoarthritis: A Retrospective Study.

Objectives: Many surgeons avoid performing unicompartmental knee arthroplasty (UKA) due to various concerns. Cohort studies showing the satisfactory outcomes of UKA can convince surgeons to use this technique. In this study, we report the mid-term outcomes of UKA in a series of patients with medial compartment knee osteoarthritis. Methods: Seventeen patients with unicompartmental degenerative joint disease of the knee that underwent UKA and were available for final evaluation were included. The mean age of the patients was 63 ± 5.1 years. The mean follow-up of the patients was 37.2 ± 18.3 months. The outcome measures were the Oxford Knee Score (OKS), Knee Society Score (KSS) for knee score and knee function, Knee injury and Osteoarthritis Outcome Score (KOOS), knee range of motion (ROM), and satisfaction rate on a 5-point Likert scale. Results: In the last follow-up visit, the mean of OKS and knee score section of the KSS were 44.6 ± 3.2 and 83.8 ± 2.1, respectively. The mean knee function section of the KSS was measured at 98.2 ± 7.2. The mean KOOS score and the mean knee ROM were 84 ± 9.4 and 134.4 ± 7º, respectively. The mean VAS for pain was 8.9 ± 1.1 (range 8-10) before the operation and 1.2 ± 0.8 (range 0-2) at the last follow-up. All the patients were very satisfied (n=14) or satisfied (n=3) with the results. No postoperative complication or reoperation was recorded during the follow-up. Conclusion: Unicompartmental knee arthroplasty provides satisfactory outcomes and a high survival rate, at least in mid-term follow-up. These findings suggest increased use of UKA in future workups.

Pes anserine detachment in posteromedial approach to the tibial plateau fracture provides better intraoperative exposure without compromising the flexor muscle strength.

PURPOSE: During the posteromedial approach to the tibial plateau fracture (TPF), pes anserine is generally retracted. However, pes anserine detachment could provide a better fracture site exposure. Even so, the general conception is that the latter could negatively affect flexor muscle strength. We aimed to evaluate the effect of pes anserine detachment on the flexion force and functional outcomes of TPF with posteromedial involvement. METHODS: In this retrospective-prospective cohort study, 22 TPF patients with Schatzker type IV who were managed with posteromedial approach and pes anserine detachment were included. The knee flexion force was measured 12 months after the surgery at several angles of flexion (30°, 60°, and 90°) and rotations (internal and external). The International Knee Documentation Committee (IKDC) and the Knee Injury and Osteoarthritis Outcome Score (KOOS) were used to assess knee function. A visual analog scale (VAS) was used to measure knee pain. RESULTS: The mean strength of the knee flexor muscle was not statistically different between the involved and non-involved sides at 30°, 60°, and 90° knee flexion, and also at the internal and external rotation. The mean IKDC score of the patients was 81.6 ± 7.8. The mean KOOS score of the patients was 82.2 ± 9.1. The mean VAS for pain was 2.4 ± 1.8. The mean knee range of motion was 124 ± 10.5°. CONCLUSION: Pes anserine release and re-attachment in the posteromedial approach to the TPF has no detrimental effect on the flexion muscle strength and knee function. LEVEL OF EVIDENCE: Therapeutic Level IV.

Comparison of intramedullary nail and plating in treatment of diaphyseal tibial fractures with intact fibulae: A randomized controlled trial.

BACKGROUND: Tibial fracture without concomitant fibular fracture is an injury that has long attracted notice for the fact that it sometimes heals cleanly, other times causes various problems when the bone does not heal, or misaligns. In this randomized clinical trial, we assessed two treatment modalities plating and intramedullary nailing for treatment of closed, noncomminuted tibial fractures with intact fibulae. MATERIALS AND METHODS: During the three year period, 1470 patients with leg fractures were treated and out of which, 114 were eligible to enter the study. Of the eligible patients, 73 were recruited to enter the trial, and ultimately 69 of these were followed for at least one year. The patients were randomized into two groups, one of which was treated by plating of the fracture, the other group by intramedullary nailing, both of which are standard surgical procedures. The primary variables that influenced the outcome of the procedures in both treatments were the duration of surgery, the amount of bleeding, the time to union, the need to repeat surgery to achieve union, the need to remove a device, and patients' complaints about pain or discomfort in the limb. RESULTS: One case of nonunion occurred in the group treated with intramedullary nailing and one of the patients in this group developed late, deep infection in the screws location, which was resolved by screw removal (P = 0.285 and P = 0.478, respectively). In both groups the tibial fractures achieved union in about 4 months, though the intramedullary group underwent more operations to achieve union (dynamization was performed in 4 patients, representing 12.1% of the patients in this group, P = 0.047). During the followup period, the incidence of implant removal (after union) was not statistically significant between the two groups: two patients (6.1%) in the intramedullary group and four patients (11.1%) in the plate group (P = 0.675) had implants removed. Of the other studied variables, the difference between the two groups was statistically significant only with regard to patients' complaints of pain in the limb and the number of individuals with knee pain (in both cases, P = 0.001). In the intramedullary group, 18 patients had no complaints (54.4%) and 13 complained of knee pain (39.4%), while in the plate group 29 had no complaints (80.6%). CONCLUSION: Based upon the findings of the present study, both the methods studied are suitable treatments for closed noncomminuted isolated tibial fractures, but the patients in whom intramedullary nails are used are more likely to require additional surgeries to achieve union, and probably will have more complaints of pain in their limbs or knees.