Workshop on personal motion technologies for healthy independent living: executive summary.

The objective of the June 2010 "Workshop on Personal Motions Technologies for Healthy Independent Living" was to discuss personal motion technologies that might enable older adults and individuals with disability to live independently for longer periods. The 60 participants included clinicians, academic researchers, engineers, patient advocates, caregivers, members of the public, and federal representatives. The workshop was divided into 6 sessions that addressed the following: (1) use of technologies in identifying early indicators of disease or adverse events; (2) monitoring daily activities; (3) coping with impairment; (4) managing mild cognitive impairment; (5) rehabilitation and exercise in the home; and (6) caregiver support. Presentations and discussion focused on clinical needs, the health impact of addressing those needs, state-of-the-art technologies, and challenges to adoption of those technologies. Conclusions included the following: (1) Involvement of end-users in research and development will increase the likelihood that technologies will be adopted. (2) Integration of differing types of technology into a system that includes clinical measures is required for independent living. (3) Seniors are willing to sacrifice some privacy for an effective technology that keeps them in their homes as long as they control who receives their data. (4) Multilevel and multiscale models are needed to understand motion in the context of the environment and to design effective systems.

Codominance of the individual posterior cruciate ligament bundles. An analysis of bundle lengths and orientation.

BACKGROUND: It is unclear how each bundle of the posterior cruciate ligament contributes to posterior knee stability. HYPOTHESIS: Changes in bundle orientation and length occur such that neither bundle dominates in restraining posterior tibial motion throughout knee flexion and extension. STUDY DESIGN: Controlled laboratory study. METHODS: Six fresh-frozen cadaveric knees were studied in a joint-testing rig with individual quadriceps and hamstring muscle loading. Kinematic data for the tibia and femur were obtained at knee flexion angles from 0 degrees to 120 degrees. The joint was then disarticulated, and the insertions of the two bundles on the tibia and femur were digitized. RESULTS: Length of the anterolateral bundle increased with increasing knee flexion angle from 10 degrees to 120 degrees. Length of the posteromedial bundle decreased with increasing knee flexion angle from 0 degrees to 45 degrees and increased slightly from 60 degrees to 120 degrees. Length of the anteromedial bundle was significantly less than that of the posteromedial at 0 degrees, 10 degrees, and 20 degrees of knee flexion. The anterolateral bundle was significantly more horizontal at flexion angles of 0 degrees, 10 degrees, 20 degrees, 30 degrees, and 45 degrees (P < 0.05). The posteromedial bundle was more horizontal at 120 degrees. CONCLUSIONS: Changes in orientation take place such that neither bundle dominates in restraining posterior tibial motion throughout knee flexion and extension. CLINICAL RELEVANCE: Double-bundle reconstructions achieve more physiologic knee function.

Computer simulations of patellofemoral joint surgery. Patient-specific models for tuberosity transfer.

BACKGROUND: Variable clinical outcomes of tibial tuberosity transfer surgery have been reported. HYPOTHESES: The biomechanical outcome of surgery is patient-specific; no single procedure produces superior results for all patients. Use of patient-specific computer models can optimize choice of procedure. STUDY DESIGN: Computer simulation study using clinical data. METHODS: We used patient-specific multibody models of the patellofemoral joints of 20 patients with a diagnosis of patellar subluxation and osteoarthritis. Four tibial tuberosity transfer procedures (two anterior and two anteromedial) were simulated for each patient and compared with their preoperative model. RESULTS: When results for all patients were averaged, all simulated operations produced a statistically significant decrease in surface-wide mean contact stress, although no significant difference was found among them. CONCLUSIONS: The simulated surgical outcomes were patient-specific: no single procedure was consistently superior at decreasing peak or mean stress and each procedure produced a potentially detrimental outcome, an increase in either mean stress or peak stress, in at least one patient. CLINICAL RELEVANCE: Computer simulation may serve as a valuable tool for tailoring procedures to specific patients.