Midterm Performance of a Guided-Motion Bicruciate-Stabilized Total Knee System: Results From the International Study of Over 2000 Consecutive Primary Total Knee Arthroplasties.

BACKGROUND: The JOURNEY II Bi-Cruciate Stabilizing Total Knee System (BLINDED) is a second-generation guided-motion knee implant that has been used in over 100,000 primary total knee arthroplasties (TKAs) worldwide. However, performance information is limited. METHODS: Data for 2059 primary TKAs were abstracted at 7 US and 3 European sites. Estimates of cumulative incidence of revision were compared with registry data for cemented posterior-stabilized implants. RESULTS: Average age was 64.3 years (range, 18-91); 58.5% were females; and 12.3% TKAs were in subjects younger than 55 years. Patellae were resurfaced in 95.9%. Median time since primary TKA was 4.2 years; longest was 6.1 years; and 78.9% were 3 years or more since primary TKA. Of 67 revisions (3.2%), 20 (30%) involved femoral or tibial component removal compared to 42% in the Australian Joint Registry (Australian Orthopedic Association National Joint Replacement Registry). All-component revisions accounted for 15 of 67, femoral component only for 2 of 67, tibial component only for 3 of 67, patellar component with/without tibial insert exchange for 17 of 67, and isolated tibial insert exchange for 30 of 67. In addition, there were 18 reoperations without component exchange. Component revision indications were infection (33%), mechanical loosening (21%), fracture of bone around the joint (16%), and instability (15%). Kaplan-Meier revision estimate was 3.1 and 3.6 per 100 TKAs at 3 and 5 years, respectively, compared to Australian Orthopedic Association National Joint Replacement Registry estimates of 3.1 and 4.1 per 100 TKAs. CONCLUSION: The revision rate for the second-generation implant was similar to cemented posterior-stabilized registry controls.

The effects of magnetic resonance imaging on surgical staples: an experimental analysis.

BACKGROUND: Surgical staples are commonplace in repairing surgical incisions. Staples allow for expeditious closure and removal compared with suture materials. However, there are clinical concerns when obtaining a magnetic resonance imaging (MRI) scan with staples present. This study examined two issues related to MRI scanning in the presence of surgical staples: skin surface temperature change and staple displacement. METHODS: Thirty pig feet had 3-cm surgical incisions repaired with five surgical staples. Once placed, each skin staple position was marked for later referencing. A surface temperature laser device recorded prescan skin surface temperature. A 35-minute MRI scan was performed with a 1.5-Tesla magnet and standard knee coil for each pig foot. Immediately afterward, the skin surface temperature and displacement measurements were recorded. The paired t test was used to analyze temperature change from prescan to postscan. RESULTS: The prescan mean temperature was 16.45°C (standard deviation: 0.70°C), and the range was 14.60°C to 18.20°C. After scanning, the mean temperature was 16.02°C (standard deviation: 0.63°C), and the range was 15.00°C to 17.60°C. The decrease of 0.43°C in skin surface temperature was statistically significant (p=0.001). No change in staple position was measurable or evident by visual inspection for any of the pig feet. CONCLUSION: This study found no increase in skin surface temperature or displacement of staple position after a standard extremity MRI scan. Based on our findings, MRI scanning in the presence of stainless steel surgical staples seems safe.

Inter- and intraobserver reliability in the radiographic evaluation of adult flatfoot deformity.

BACKGROUND: Adult acquired flatfoot is a complex deformity with numerous radiographic measurements described to define it. The purpose of this study was to evaluate the inter- and intraobserver reliability of six radiographic measurements using digital and conventional radiographs. MATERIALS AND METHODS: Three digital weightbearing radiographs consisting of anteroposterior, lateral, and hindfoot alignment views were obtained at presentation for 20 consecutive patients. Six radiographic measurements were made for each patient: talus/second metatarsal angle, calcaneal pitch angle, talus/first metatarsal angle, medial cuneiform/fifth metatarsal distance, tibial/calcaneal displacement, and calcaneal angulation. Each radiograph was evaluated on multiple occasions by a senior orthopaedic surgery resident, a junior orthopaedic surgery resident, and a third-year medical student. Inter- and intraobserver reliability was determined using measurements made on digital radiographs. RESULTS: Interobserver reliabilities were 0.830 for talus/second metatarsal angle, 0.948 for calcaneal pitch angle, 0.781 for talus/first metatarsal angle, 0.991 for medial cuneiform/fifth metatarsal distance, 0.870 for tibial/calcaneal displacement, and 0.834 for calcaneal angulation. Interobserver reliability was similar for digital and conventional radiographs, and intraobserver reliability increased with observer experience. CONCLUSION: Adult acquired flatfoot deformity is a complex condition that is difficult to quantify radiographically. The medial cuneiform/fifth metatarsal distance and the calcaneal pitch angle were found to have the highest interobserver reliability. Intraobserver reliability increased with observer experience.