Evaluating two implant designs in patients undergoing primary total knee arthroplasty using a novel measure of early optimal recovery: a retrospective observational study.

PURPOSE: Quality of care in total knee arthroplasty (TKA) between implants was assessed using a novel composite outcome measure, early optimal recovery (EOR), to indicate ideal clinical outcomes and minimal healthcare resource utilization. METHODS: Patients that underwent primary TKA in the study group (ATTUNE® Knee System) or control group (LCS® COMPLETE Knee System) were included in this retrospective, single-center study. EOR was defined as no complications, no readmissions, no extra outpatient visits, ≤ 48 h length of hospital stay (LOS), and restored range of motion and pain perception at 3-month follow-up. Multivariate logistic regression was used to compare EOR between the study and control groups. Results were adjusted for differences in baseline characteristics and are presented with 95% confidence intervals (CI). Data were collected from a specialized clinic for elective surgeries in the Netherlands, between January 2017 and December 2020. RESULTS: A total of 566 patients (62.4% female, mean age 67 years) were included for analysis; 185 patients (32.7%) underwent TKA in the study group. Compared to the control group, patients in the study group had greater probability of achieving EOR (65.8% [95% CI: 55.1-75.2] vs. 38.9% [95% CI: 32.8-45.3]; p < 0.001), a LOS ≤ 48 h (77.2% [95% CI: 67.7-84.5] vs. 61.4% [95% CI: 54.7-67.7]; p < 0.05), and ideal pain perception at 3-month follow-up (93.3% [95% CI: 85.7-97.0] vs. 78.2% [95% CI: 71.0-83.9]; p < 0.05). CONCLUSION: The study group was associated with a greater probability of achieving EOR versus the control group, suggesting improved quality of care.

Functional acetabular component position with supine total hip replacement.

Orientation of the acetabular component influences wear, range of movement and the incidence of dislocation after total hip replacement (THR). During surgery, such orientation is often referenced to the anterior pelvic plane (APP), but APP inclination relative to the coronal plane (pelvic tilt) varies substantially between individuals. In contrast, the change in pelvic tilt from supine to standing (dPT) is small for nearly all individuals. Therefore, in THR performed with the patient supine and the patient's coronal plane parallel to the operating table, we propose that freehand placement of the acetabular component placement is reliable and reflects standing (functional) cup position. We examined this hypothesis in 56 hips in 56 patients (19 men) with a mean age of 61 years (29 to 80) using three-dimensional CT pelvic reconstructions and standing lateral pelvic radiographs. We found a low variability of acetabular component placement, with 46 implants (82%) placed within a combined range of 30° to 50° inclination and 5° to 25° anteversion. Changing from the supine to the standing position (analysed in 47 patients) was associated with an anteversion change < 10° in 45 patients (96%). dPT was < 10° in 41 patients (87%). In conclusion, supine THR appears to provide reliable freehand acetabular component placement. In most patients a small reclination of the pelvis going from supine to standing causes a small increase in anteversion of the acetabular component.

Human hip impingement morphology: an evolutionary explanation.

We examined the morphology of mammalian hips asking whether evolution can explain the morphology of impingement in human hips. We describe two stereotypical mammalian hips, coxa recta and coxa rotunda. Coxa recta is characterised by a straight or aspherical section on the femoral head or head-neck junction. It is a sturdy hip seen mostly in runners and jumpers. Coxa rotunda has a round femoral head with ample head-neck offset, and is seen mostly in climbers and swimmers. Hominid evolution offers an explanation for the variants in hip morphology associated with impingement. The evolutionary conflict between upright gait and the birth of a large-brained fetus is expressed in the female pelvis and hip, and can explain pincer impingement in a coxa profunda. In the male hip, evolution can explain cam impingement in coxa recta as an adaptation for running.

Abnormal bone scans in anterior cruciate ligament deficiency indicate structural and functional abnormalities.

Many patients with anterior cruciate ligament (ACL) deficiency have an abnormal bone scan. This finding has not yet been explained. Suggested explanations include intra-articular (structural) or kinematic (functional) abnormalities. We examined the relationship between bone scintigraphy and cartilage degeneration or meniscal lesions in the ACL-deficient knee in 95 consecutive patients who had bone scintigraphy 1-3 days prior to arthroscopic ACL reconstruction. Intra-articular abnormalities of the knee did not explain all scintigraphic patterns of this study. We did not find clinically useful positive predictive values for scintigraphic patterns considered to indicate cartilage degeneration or a lateral meniscus lesion. A clinically useful positive predictive value was found only for medial meniscus lesions when time since ACL rupture was more than 18 months, and for local cartilage degeneration when markedly increased uptake was seen when time since ACL rupture was more than 4 months. Considering these findings, alternative explanations are discussed, based on specific aspects of abnormal kinematics and adaptive bone metabolism of the ACL-deficient knee.

Abnormal bone scans of the tibial tunnel 2 years after patella ligament anterior cruciate ligament reconstruction: correlation with tunnel enlargement and tibial graft length.

Tibial bone tunnels were examined with bone scans 2 years after patella ligament ACL reconstruction in 68 patients. At 2 years, scan uptake at the tibial tunnel was increased in 29% of patients. Marked increase of scintigraphic uptake was associated with tibial tunnel enlargement of more than 35% and a graft length in the tibial tunnel over 14 mm. Scan uptake was correlated to tunnel enlargement (r = 0.64, P < 0.01) and tunnel enlargement was correlated to graft length inside the tibial tunnel (r = 0.59 P < 0.001). No correlation was found between scan uptake or tunnel enlargement and anterior laxity, sagittal tunnel position and subjective outcome. Scintigraphy indicates the enlarged tibial tunnels are filled with remodelling bone. Tibial fixation location influences ligament healing inside the tunnel: Return of osseous homeostasis at the tibial tunnel can take more than 2 years when fixation is more than 14 mm below the joint.