Can We Predict Severity of Osteoarthritis of Knees and Compartmental Involvement Based on a Set of Predefined Clinical Questions in Patients of Knee Pain?

BACKGROUND: We investigated whether the severity of Osteoarthritis (OA) knees can be predicted based on a set of predefined clinical questions (PCQs) about activities of daily living (ADL). We studied the association of demographic factors and advanced radiographic OA (KL 3 and 4) and the relationship between various physical activities and radiographic involvement of knee joint compartments based on PCQs. MATERIALS AND METHODS: Demographic data, radiographic grading of knee OA and PCQs score, were obtained prospectively. Patients' responses to PCQs were marked as scores-that were predefined and graded according to the severity of knee pain. Radiographic knee OA grades were dichotomized and patients were classified as either negative (KL grade 1, 2) or positive (KL grade 3, 4). Multivariate logistic regression was performed to obtain the adjusted odds for total PCQs score in relation with positive radiographic OA considering confounders like age, gender and BMI in the model. Log odds score (LOS) were obtained and ROC analysis was performed on scores to obtain the cut-off value for the screening of knee OA in patients of knee pain. RESULTS: Age and BMI were significantly negatively correlated with PCQs score (r = - 0.473; P < 0.0001 and r = - 0.136; P = 0.046). PCQs scores were significantly lower in females (P = 0.031). Total PCQs score had corresponding OR of 0.901 (P = 0.002) towards knee OA after adjusting for age, gender and BMI. Multivariate model-based LOS resulted in a cut-off of 1.315, which had a sensitivity of 85.5%, specificity of 66.7% and PPV of 92.7%. CONCLUSION: Severity of knee OA can be predicted based on PCQs. PCQs can predict severity of knee OA and patellofemoral or medial tibiofemoral compartment without radiographs. LOS based on demographics and total PCQs score can be developed as a screening tool for advanced knee OA.

Total knee arthroplasty with computer-assisted navigation more closely replicates normal knee biomechanics than conventional surgery.

BACKGROUND: Computer-assisted navigation in total knee arthroplasty (TKA) reduces variability and may improve accuracy in the postoperative static alignment. The effect of navigation on alignment and biomechanics during more dynamic movements has not been investigated. METHODS: This study compared knee biomechanics during level walking of 121 participants: 39 with conventional TKA, 42 with computer-assisted navigation TKA and 40 unimpaired control participants. RESULTS: Standing lower-limb alignment was significantly closer to ideal in participants with navigation TKA. During gait, when differences in walking speed were accounted for, participants with conventional TKA had less knee flexion during stance and swing than controls (P<0.01), but there were no differences between participants with navigation TKA and controls for the same variables. Both groups of participants with TKA had lower knee adduction moments than controls (P<0.01). CONCLUSIONS: In summary, there were fewer differences in the biomechanics of computer-assisted navigation TKA patients compared to controls than for patients with conventional TKA. Computer-assisted navigation TKA may restore biomechanics during walking that are closer to normal than conventional TKA.

Long-term Results of a First-Generation Annealed Highly Cross-Linked Polyethylene in Young, Active Patients.

The survivorship of total hip arthroplasty in younger patients is dependent on the wear characteristics of the bearing surfaces. Long-term results with conventional polyethylene in young patients show a high failure rate. This study assessed the long-term results of a first-generation annealed highly cross-linked polyethylene (HCLPE) in uncemented total hip arthroplasty in young, active patients. Between 1999 and 2003, 112 total hip arthroplasty procedures performed in 91 patients with an average University of California Los Angeles activity score of 8 and mean age of 53 years (range, 24-65 years) were included from a prospective database. In all patients, a 28-mm metal femoral head on annealed HCLPE (Crossfire; Stryker, Mahwah, New Jersey) was used. At minimum 10-year follow-up (11.5±0.94 years), Kaplan-Meier survivorship was 97% for all failures (1 periprosthetic infection and 1 late dislocation) and 100% for mechanical failure (no revisions for osteolysis or loosening). This study showed low revision rates for wear-related failure and superior survivorship in young, active patients. Oxidation causing failure of the locking mechanism has not been a problem with Crossfire for up to 10 years.

Navigation-assisted minimal invasive total knee arthroplasty in patients with extra-articular femoral deformity.

In the presence of extra-articular femoral deformity, total knee arthroplasty (TKA) is difficult to perform because of altered anatomical axis and distorted landmarks. Although minimal invasive surgery (MIS) has known advantage of earlier rehabilitation, MIS with this deformity may have higher incidence of component malposition due to inadequate exposure. Navigation has been shown to increase the accuracy of alignment and may compensate possible complication of MIS. We report 4 cases with extra-articular femoral deformity that underwent MIS-TKA using an image-free navigation system in which preoperatively planned mechanical alignment was surgically achieved with proper positioning of the implants as well as soft tissue balance. Navigation-assisted MIS-TKA may become a valuable mean especially for a patient with a deformed femur in which conventional instruments are difficult to use correctly.