Search

Introduction: A virtual reality simulator developed for orthopaedic and trauma surgical training has been introduced. However, it is unclear whether the experiences of actual surgery are reflected in virtual reality simulation surgery (VRSS) using a simulator. The aim of this study is to investigate whether the results in VRSS differ between a trauma expert and a trauma novice., Methods: In Group A (expert), there are ten orthopaedic trauma surgeons and in Group B (novice) ten residents within 2 years after medical school graduation. VRSS for a femoral neck fracture using Hansson hook-pins (Test 1) and Hansson twin hook plate (Test 2) was performed. The parameters evaluated were total procedure time (s), fluoroscopy time (s), number of times X-ray was used (defined by the number of times the foot pedal was used), number of retries in guide placement, and final implant position., Results: In Test 1, the averages of four parameters (distance to posterior cortex (p = 0.009), distal pin distance above lesser trochanter (p = 0.015), distal pin hook angular error (p = 0.004), and distal pin tip distance to centre (lateral) (p = 0.015)) were significantly different between Groups A and B. In Test 2, no parameters in a mean were significantly different between groups, but seven parameters in a variance (guide wire distance to joint surface (p = 0.0191), twin hook length outside barrel (p = 0.011), twin hook tip distance to centre (lateral) (p = 0.042), twin hook distance to centre of lateral cortex (lateral) (p = 0.016), plate end alignment error (lateral) (p = 0.027), guide wire angle with lateral cortex (front) (p = 0.024), and 3.2-mm drill outside cortex (p = 0.000)) were significantly different between groups. In Test 1, Group B showed significantly longer fluoroscopy time than Group A (p = 0.044). In Test 2, Group B showed significantly fewer instances of X-ray use than Group A (p = 0.046)., Conclusions: Our study showed that the experiences of actual surgery are reflected in the result of VRSS using the simulator.

Introduction: In total hip arthroplasty via a direct anterior approach, the femur must be elevated at the time of femoral implant placement. For adequate elevation, division of the posterior soft tissues is necessary. However, if we damage and separate the posterior muscle tissue, we lose the benefits of the intermuscular approach. Furthermore, damage to the posterior soft tissue can result in posterior dislocation. We investigate that protecting the posterior soft tissue increases the joint stability in the early postoperative period and results in a lower dislocation rate., Methods: We evaluated muscle strength recovery by measuring the maximum width of the internal obturator muscle on CT images (GE-Healthcare Discovery CT 750HD). We compared the maximum width of the muscle belly preoperatively versus 10 days and 6 months postoperatively. As clinical evaluations, we also investigated the range of motion of the hip joint, hip joint function based on the Japanese Orthopaedic Association hip score (JOA score), and the dislocation rate 6 months after surgery., Results: The width of the internal obturator muscle increased significantly from 15.1 ± 3.1 mm before surgery to 16.4 ± 2.8 mm 6 months after surgery. The JOA score improved significantly from 50.8 ± 15.1 points to 95.6 ± 7.6 points. No dislocations occurred in this study., Conclusions: We cut only the posterosuperior articular capsule and protected the internal obturator muscle to preserve muscle strength. We repaired the entire posterosuperior and anterior articular capsule. These treatments increase joint stability in the early postoperative period, thus reducing the dislocation rate., Level of Evidence: Therapeutic, Level IV.

In the present study, the adaptability of the distal radioulnar joint (DRUJ) was evaluated using conventional computed tomography (CT) evaluation methods. In addition, we investigated/compared a new method to evaluate dorsal displacement of the ulnar head. Our subjects consisted of 32 healthy volunteers (64 wrists) and 11 patients (13 wrists) with extensor tendon injuries related to dorsal displacement of the ulnar head. To diagnose instability in the DRUJ based on CT scans, the radioulnar line method and the modified radioulnar line method were measured. Instability was evaluated by the new method that the ulnar head was located on the dorsal side from a line involving the peak of Lister's tubercle in parallel to this baseline was regarded as showing abnormal dorsal displacement of the ulnar head. The diagnostic accuracy of each method was calculated. The sensitivities, specificities, false-positive rates, positive predictive values and the negative predictive value of new methods were better than other two methods. The new method that we recommend is simple. Based on the results of this study, an evaluation of normal/abnormal dorsal displacement of the ulnar head in the DRUJ using the new method may be useful for determining the timing of surgery.

Rupture of the triceps tendon is a rare condition. We report a case of triceps tendon rupture with avulsion fracture of the olecranon with discussion about pathogenesis from the viewpoint of healing of the olecranon ossification nucleus. An 18-year-old man presented with avulsion fracture of the olecranon and triceps tendon rupture. Operative treatment was conducted with good results. Rupture of the triceps tendon is a rare injury comprising approximately 2% of all tendon injuries, and avulsion at insertion into the olecranon is the most common site of rupture. This injury is most likely to happen in young people as sports-related trauma. Among young people who have insufficient healing of the olecranon ossification nucleus, avulsion fracture of the olecranon may occur due to strong contraction force of the triceps tendon. Our clinical evidence may suggest that avulsion fracture of the olecranon is related in olecranon ossification center healing. Most triceps tendon ruptures are accompanied by avulsion fracture of the olecranon, and it is important to suspect this injury when radiographs show a small fleck of bone avulsed from the olecranon.

In total hip arthroplasty of the acetabular roof fixed by press-fit without screw fixation, there is little possibility for loosening to occur, because it is difficult for wear debris to enter between the cup and the acetabular roof, as screw holes are not present. However, stability is provided only by contact. In the case of acetabular dysplasia, it is not well understood whether sufficient initial fixation power is provided. We performed a torsion test and a lever-out test. In the torsion test, in the case of a normal hip joint, as the cup grew bigger, the fixation power tended to increase in strength. In the acetabular dysplasia model, with cups of each size, as the protrusion angle increased, the fixation power of the cup tended to become weak. When the protrusion angle approaches 15 degrees, we must use a cup that is 4 mm larger than the original cup to achieve the same initial fixation power. Furthermore, when the protrusion angle is 15 degrees in cups that are over 48 mm in size, we obtain fixation power that is theoretically adequate, but when small cups, for example, 46 mm in size are set with protrusion, the initial fixation power decreases significantly, and we cannot obtain a fixation power that is theoretically adequate.