Background: We encountered five patients of post-THA femoral stem fracture without femoral fracture. The purpose of this study was to elucidate the mechanism underlying the observed femoral stem fractures.

Methods: We performed an assessment of the cement mantle using plain radiographic images. We analyzed the state of the fractured stems and fractured surfaces of these stems during the revision surgery. Additionally, we replicated the same prosthesis support conditions that were present around the fractured stems and verified the analytic results by using mechanical tests (bending test, fatigue test), finite element method (FEM) analysis and material tests. Bending tests were performed at a loading rate of 5 mm/min. In contrast, for fatigue testing, the bending tests were repeated under a loading of 2300 N at a frequency of 5 Hz. The cemented distal portions of the fractured stems were all firmly attached, but the proximal portions were unsupported. During these simulation tests, the distal portion was fixed at a distance of 80 mm from the center of the femoral head using a 36-mm femoral head.

Results: The plain radiographic images at the time of the stem fracture showed that radiolucencies were observed in all patients around the proximal regions of the stem, although good fixation was obtained at the distal portions. We could easily remove the parts of the stem proximal to the fracture site in all patients during surgery, while the distal parts were solidly cemented. Examination of the fracture surfaces showed that the fracture origin was on the lateral surface in the middle of the stem. The middle portion of the stem bent during the compression-bending test, with this position corresponding to the fracture site. FEM analysis showed that the area corresponding to the stem fracture origin was the same as predicted from examining the fractured surface.

Conclusion: Bending test and FEM showed that only the distal part of Co–Cr alloy stem was firmly fixed and the internal stress was concentrated at a point just proximal to the fixed part. Therefore, this point coincided with the fractured point of the stem.

Objectives: This study aimed to investigate the effect of high-frequency mirror therapy (MT) on the upper extremities of patients suffering paresis following subacute stroke. Altogether, 50 subacute stroke patients with upper limb paresis whose strokes had occurred within 30–60 days of the start of this study were enrolled. The patients were randomly divided equally into groups assigned to conventional therapy (CT) alone or to CT plus mirror therapy (MT). All patients underwent CT training 40 min daily for 4 weeks. The MT group patients then continued an additional 20 min of shoulder, elbow, wrist, and finger MT, whereas the CT group continued with an additional 20 min of CT. Main outcome measures were the angles achieved during active shoulder flexion and abduction and wrist dorsiflexion, as well as upper-limb Fugl–Meyer Assessment (FMA) subscores.

Results: For both the intention-to-treat and per-protocol analyses, the MT group showed significantly more improvement in active shoulder flexion range of motion than did the CT group. The FMA scores improved from before to after the start of the study in both groups, with no significant differences between the two groups.

Conclusions: Application of MT at a high frequency probably has a positive effect on improving shoulder function in these subacute stroke patients. Thus, frequent MT application is essential for alleviating stroke-induced paralysis.

Objectives: This study examined the reliability of one repetition maximum measurement (1RM) for leg extension using an improved leg extension machine through a comparison between before and after machine improvement.

Methods: Twenty-one healthy adult males were recruited. A ratchet was welded to the knee rotation axis of the leg extension machine to prevent counter rotation due to the free fall of weights. The 1RM measurement for knee extension was performed before and after machine improvement to observe changes in their reliability using the intra-class correlation coefficient (ICC).

Results: After machine improvement, an intra-rater reliability of ICC_(1,1)=0.99 and inter-rater reliability of ICC_(2,1)=0.99 were achieved. Reliability before and after machine improvement was also high, with ICC_(2,1)=0.99.

Conclusions: The reliability of 1RM measurement for leg extension using an improved leg extension machine was high.

Objective: Accidents that occurred during rehabilitation training were retrospectively analyzed to understand the risks involved in rehabilitation training.

Methods: Subjects were 33,905 patients who underwent rehabilitation training at an acute-care hospital over an 8-year period. In total, 457 accidents occurred during rehabilitation training and were analyzed. Data collected were: accident incidence rate, patient’s position/behavior at the time of the accident, state of assistance/supervision by the therapist in charge, and annual number of accidents per therapist by years of experience.

Results: Most accidents that occurred during rehabilitation training involved bleeding, falls, and route-related accidents (accidents related to use of catheters, intravenous lines, or nasogastric tubes), in that order. Half of the accidents occurred in a training room. Bleeding was associated with a variety of behaviors, including lying, sitting, and walking, and 40% of falls occurred while walking. Examination of the number of accidents per therapist by years of experience showed patients tended to experience accidents when being assisted/supervised by therapists with 1–4 years of experience.

Conclusions: Many accidents that occurred during rehabilitation training at this acute-care hospital involved bleeding or falls. Accidents were more common when a therapist with only a few years of experience was conducting the training.

Objectives: Operative therapy for proximal humerus fractures in older patients has improved recently, but the optimal surgical procedure is still controversial in those with osteoporosis. Generally, hemiarthroplasty (HA) is indicated in older patients with osteoporosis with three part, group-6 fractures or worse, according to the Neer classification system. To recover a good range of motion (ROM), bone fragments of the greater tubercle and lesser tubercle must be united with a humeral implant. Occasionally, these fragments are displaced during follow-up. However, even when their position unchanged, osteolytic changes can occur. We treated two patients with reverse shoulder arthroplasty (RSA) who both exhibited good functional results postoperatively.

Methods: Two patients (mean age: 82 years) who sustained proximal humerus fractures were clinically and radiographically evaluated. Fracture types included three-part, group-6, and four-part, group-6 fractures according to the Neer classification. The mean follow-up period was 17 months. After the two patients were treated with RSA, their shoulder ROM was evaluated until the final follow-up.

Results: Osteolytic changes in the greater tubercle were observed during the course of treatment in both patients. The mean active shoulder ROM for elevation, abduction, external rotation, and internal rotation was 120°, 110°, 25°, and to L5, respectively.

Conclusions: We obtained good functional results with RSA in two older patients with proximal humerus fractures and thus believe that RSA can be an appropriate treatment for complicated proximal humerus fractures in older adults.