Joint Restoration Research Articles

Delayed laryngeal reinnervation

Objective. To test the feasibility of selective abductor reinnervation with a delay period of 9 months after transectionof the recurrent laryngeal nerve (RLN). Successful laryngeal abductor function restoration has been achieved in the cat model, using the phrenic nerve (PN) to reinnervate the abductor muscle, in the acute phase, but in clinical practice there is usually a considerable period of delay between the time of injury to the RLN and the moment the patient presents for treatment. Materials and methods. The right RLN was severed in 12 cats. Nine months later the PN was anastomosed to the distal RLN stump and all its branches were diverted to the posterior cricoarytenoid (PCA) muscle. Ten weeks after the reconstruction, electromyography, videolaryngoscopy and histological analysis were performed. Results. Eleven cats could be evaluated. Videolaryngoscopyshowed adequate to good abduction in only four cats although inspiratory EMG activity was found in the right PCA muscle in 10 cats. A high correlation was found between reduced mobility of the cricoarytenoid joint and poor restoration of abduction movement. Conclusion. Selective laryngeal abductor reinnervation has proved possible in the cat model even after a delay of 9 months, but restoration of abduction appears to be negatively influenced by reduced mobility of the cricoarytenoid joint.

Total knee arthroplasty kinematics: Computer simulation and intraoperative evaluation

The goal of this work was to develop computer simulations for intraoperative testing of the passive kinematics of knee prostheses. These are based on an anatomic model of the reconstructed joint, represented in the sagittal plane. A femoral component and a tibial component are linked by 3 springs that model the relevant ligaments, with the posterior cruciate providing the primary constraint. The components' behavior at each flexion angle is obtained by minimizing the total strain energy stored in the ligaments. Simulations were performed in vivo on 10 Interax implants (Howmedica International, Stain, UK) and showed good agreement with intraoperative observations, allowing monitoring of new parameters such as contact point motion, ligament strains, and the energetic state of the knee. This work contributes to the comprehension of individual knee kinematics after total knee arthroplasty, to improve long-term results and standardize the evaluation of the results of joint restoration.

Interactive learning of monotone Boolean functions

This paper presents some optimal interactive algorithms for some problems related to learning of monotone Boolean functions. These algorithms are based on the fundamental Hansel theorem. The advantage of the algorithms is that they are not heuristics, as is often the case of many known algorithms for general Boolean functions, but they are optimal in the sense of the Shannon function. This paper also formulates a new problem for the joint restoration of two nested monotone Boolean functions f 1 and f 2. This formulation allows one to further decrease the dialogue with an expert and restore nonmonotone functions of the form f 2&|f 1 . The effectiveness of the proposed approaches is demonstrated by some illustrative computational experiments.

Dynamic digital traction for unstable comminuted intra-articular fracture-dislocations of the proximal interphalangeal joint

Unstable intra-articular fracture-dislocations about the proximal interphalangeal joint present a formidable management dilemma. Fourteen patients with comminuted injuries of the proximal interphalangeal joint were treated with dynamic digital traction and followed for an average of 24 months. Dorsal fracture-dislocation and pilon-type injuries made up the majority of cases. Average proximal interphalangeal joint articular surface involvement was 80%. Immediate motion was instituted after traction application. The device was applied in the office with readily available materials. At final follow-up examination, active arc of motion averaged 89 degrees at the proximal interphalangeal joint and 95 degrees for patients sustaining isolated injuries. X-ray films revealed fracture union, joint remodeling, and preservation of joint space. Patient satisfaction was high, with return to previous levels of activity and excellent functional joint restoration. Dynamic digital traction is recommended for unstable proximal interphalangeal joint fractures with comminution, including those associated with subluxation or dislocation.

Treatment of Os Calcis Fractures by Open Reduction and Internal Fixation

Over a 3-year period, 47 displaced intra-articular fractures of the os calcis in 43 patients underwent open reduction and internal fixation. A significant feature of this series is that computed tomography was used to assess all fractures both before and after surgery. Seventy-seven percent demonstrated a consistent fracture pattern with four major bone fragments. Patients underwent clinical assessment 1 year after injury; thirty-six feet (76.6%) were rated satisfactory and 11 (23.4%) were rated unsatisfactory. An unsatisfactory clinical outcome was significantly correlated with failure to obtain or maintain a satisfactory reduction (P = .004) and also with workers' compensation or liability status (P = .013). The degree of initial comminution, bilateralism, calcaneocuboid joint involvement, patient age, joint depression versus tongue-type fracture pattern, and Bohler's angle at follow-up did not correlate with the final clinical result. Postoperative computed tomography in the coronal plane was found to be mandatory for assessment of joint congruity and restoration of an adequate fibulocalcaneal space.

四肢の多発骨折に伴なう大菱形骨骨折の一例

A case of displaced fracture of the trapezium with multiple fractures of the extremities is reported. The treatment was open reduction and fixation with two Kirschner wires. Excellent results were achieved in terms of union, joint restoration and function.

Displaced dorsal oblique fracture of the hamate treated with a cortical mini lag screw

A dorsal oblique fracture of the hamate was associated with a dorsal dislocation of the base of the fifth metacarpal. Open reduction and internal fixation of the fracture with a cortical mini lag screw achieved an excellent result in union, joint restoration, and function.

Displaced vertical fracture of the trapezium treated with a small cancellous lag screw

A displaced vertical fracture of the trapezium with associated dislocation of the base of the thumb metacarpal was restored by the cancellous compression lag screw technique. Excellent results were achieved in terms of union, joint restoration, and function.

Hip joint restoration in juvenile rheumatoid arthritis.

Six children with long-standing juvenile rheumatoid arthritis and radiographic evidence of severe hip joint damage were found 6 months to 5 years afterward to have radiographic evidence of significant hip joint space widening and remodeling of articular surfaces. The disease activity had decreased and hip joint function had improved in all children. Each child had received various antiinflammatory drugs, but no specific medication could be implicated in the improvement. Evidence from animal studies suggests that intensive physical therapy with emphasis on continued weight bearing may have been important in promoting healing in these children. It appears that restoration of severely damaged hip joints in JRA can occur when the disease activity is controlled. Restoration may be favored by a child's greater potential for bone remodeling and by vigorous physical therapy with emphasis upon continued ambulation.