The influence of compressive forces across the patellofemoral joint on patient-reported outcome after bi-cruciate stabilized total knee arthroplasty

AIMS

Patellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the patellofemoral joint may affect patient-reported outcome. However, the relationship between patient-reported outcome and the intraoperative patellofemoral contact force has not been investigated. The purpose of this study was to determine whether or not a high intraoperative patellofemoral compressive force affects patient-reported outcome.

PATIENTS AND METHODS

This prospective study included 42 patients (42 knees) with varus-type osteoarthritis who underwent a bi-cruciate stabilized total knee arthroplasty and in whom the planned alignment was confirmed on 3D CT. Of the 42 patients, 36 were women and six were men. Their mean age was 72.3 years (61 to 87) and their mean body mass index (BMI) was 24.4 kg/m ² (18.2 to 34.3). After implantation of the femoral and tibial components, the compressive force across the patellofemoral joint was measured at 10°, 30°, 60°, 90°, 120°, and 140° of flexion using a load cell (Kyowa Electronic Instruments Co., Ltd., Tokyo, Japan) manufactured in the same shape as the patellar implant. Multiple regression analyses were conducted to investigate the relationship between intraoperative patellofemoral compressive force and patient-reported outcome two years after implantation.

RESULTS

No patient had anterior knee pain after total knee arthroplasty. The compressive force across the patellofemoral joint at 140°of flexion was negatively correlated with patient satisfaction (R ² = 0.458; β = -0.706; p = 0. 041) and Forgotten Joint Score-12 (FJS-12; R ² = .378; β = -0.636; p = 0. 036). The compressive force across the patellofemoral joint at 60° of flexion was negatively correlated with the patella score (R ² = 0.417; β = -0.688; p = 0. 046).

CONCLUSION

Patient satisfaction, FJS-12, and patella score were affected by the patellofemoral compressive force at 60° and 140° of flexion. Reduction of the patellofemoral compressive forces at 60° and 140° of flexion angle during total knee arthroplasty may improve patient-reported outcome, but has no effect on anterior knee pain.

Weekly injection of teriparatide for bone ingrowth after cementless total knee arthroplasty

PURPOSE

To compare bone mineral density (BMD) in patients with or without weekly injection of teriparatide to promote bone ingrowth after cementless total knee arthroplasty (TKA).

METHODS

Records of 8 men and 32 women (mean age, 75.6 years) who underwent cementless TKA for medial knee osteoarthritis with (n=20) or without (n=20) once-weekly subcutaneous/hypodermic injection of teriparatide for 48 weeks were reviewed. BMD and bone volume/total volume (BV/TV) of the bone-prosthesis interface of the proximal tibia in 6 regions of interest (ROI) were assessed at 3, 6, 9, and 12 months using multi-detector computed tomography.

RESULTS

Patients with or without weekly injection of teriparatide after cementless TKA were comparable in terms of baseline characteristics and pre- and post-operative knee range of motion and Knee Society knee and function scores. In ROI 1 (medial), ROI 3 (anteromedial), and ROI 4 (posteromedial), the BV/TV increased throughout the postoperative period in patients with weekly injection of teriparatide and declined after 6 months in patients without weekly injection of teriparatide. These 3 ROIs of the 2 groups differed significantly only in BMD at 6, 9, and 12 months. In ROI 2 (lateral), ROI 5 (anterolateral), and ROI 6 (posterolateral), both BV/TV and BMD showed a decreasing trend, and these 3 ROIs of the 2 groups did not differ significantly.

CONCLUSION

Weekly injection of teriparatide after cementless TKA promoted bone ingrowth mostly in the medial aspect of the bone-prosthesis interface.

Extension to the sacrum of previous adolescent scoliosis fusions in adult life

Numerous reports have indicated an increased risk for the development of precocious degenerative changes leading to pain in patients who had fusions done in adolescence for scoliosis, which extended into the lower lumbar spine. The anatomic situation may lead to instability, or spinal stenosis or both. This paper represents the evolving experience in reconstructive surgery for patients in whom a fusion was to be extended to the sacrum. Reconstructive surgery will require, if necessary, decompression posteriorly for spinal stenosis if present. Stabilization is acquired through an anterior and posterior approach with anterior and posterior instrumentation. The evolution of treatment modalities since 1976 shows a decreased pseudarthrosis rate from an initial 83% to 3% at present.

Imaging flaws in soldered joints of integrated circuits using an ultrasound electronic scanning technique

An electronic scanning c-scopic 25-MHz ultrasonic imaging system has been developed for high-speed precise testing of electronic parts such as ICs. Two-dimensional scanning is performed, one axis being electronic and the other mechanical. A focused beam is formed so as to be a longitudinal wave in solid samples. Voids equal to or larger than 0.2 mm in diameter in the solder are accurately detected and their sizing data agree within 0.1 mm with those measured visually through an optical microscope after destruction. The imaging performance was examined for fatigue cracks in soldered joints. In 1000 heat cycles between -55 and +150 degrees C, cracks resulted in the soldered joints of most samples, and their growth was clearly visible. By comparing the images with those observed by a scanning electron microscope, minimum cracks of 1-mum separation were found to be detectable. The c-scan imaging of a 14x14 mm area of the joints was completed in 1.2 s by the system.

[Etiological study of spinal ligament ossification with special reference to dietary habits and serum sex hormones]

We studied the relationship between dietary habits and the ossification of the posterior longitudinal ligaments (OPLL) in 55 patients. We analyzed carbon and nitrogen isotope ratios of the patients' hair in order to measure the intake of various types of food. Two sets of questionnaire on the patients' food preference and the intake are also analyzed. The patients showed a tendency to prefer vegetable protein to animal protein, in comparison with the control. In 23 OPLL male patients, level of the estrogen in the serum was higher than in the control. The results suggest that the dietary habits of OPLL patients and the sex hormone imbalance are responsible for the development of OPLL.