Non-contrast magnetic resonance imaging for diagnosing shoulder injuries.

PURPOSE: To compare preoperative non-contrast magnetic resonance imaging (MRI) with arthroscopy findings in diagnosing labral and rotator cuff tears. METHODS: 86 men and 60 women aged 21 to 70 (mean, 52) years underwent non-contrast MRI before arthroscopic operations on the glenohumeral joint. Slices were made in a transverse, parasagittal, and paracoronar orientation. The sequences used were T2- and proton-weighted for paracoronar imaging, T1- and T2-weighted for transverse and parasagittal imaging, and T2-weigthed sequences with fat suppression and short tau inversion recovery sequences. MRI was evaluated with the surgeon to eliminate interobserver bias. Arthroscopic surgery was performed by a single surgeon. If a labral or rotator cuff tear was found, surgery was performed using corkscrew anchors. RESULTS: For full thickness rotator cuff tears, MRI and arthroscopy detected them in 76 and 82 patients, respectively. One such tear found by MRI could not be confirmed by arthroscopy. MRI missed 4 subscapularis and 3 supraspinatus tears. The sensitivity and specificity of MRI in diagnosing full thickness rotator cuff tears were 0.90 and 0.91, respectively. For labral tears, MRI and arthroscopy detected them in 16 and 31 patients, respectively. One anterior labral tear detected by MRI could not be verified by arthroscopy. All 16 labral tears detected by MRI were Bankart type-I tears (of the anterior glenoid) except for one superior labral tear from anterior to posterior (SLAP tear). All 13 SLAP tears (10 type 2 and 3 type 3) except for one could be found by arthroscopy only. The sensitivity and specificity of MRI in diagnosing labral tears were 0.52 and 0.89, respectively. CONCLUSION: Non-contrast MRI is reliable only for diagnosing full thickness rotator cuff tears and anterior labral tears. Direct or indirect contrast enhancement is recommended for more differentiation. Special scan orientation is necessary for SLAP tears.

Biomechanical in vitro - stability testing on human specimens of a locking plate system against conventional screw fixation of a proximal first metatarsal lateral displacement osteotomy.

INTRODUCTION: The aim of this study was to examine resistance to angulation and displacement of the internal fixation of a proximal first metatarsal lateral displacement osteotomy, using a locking plate system compared with a conventional crossed screw fixation. MATERIALS AND METHODOLOGY: Seven anatomical human specimens were tested. Each specimen was tested with a locking screw plate as well as a crossed cancellous srew fixation. The statistical analysis was performed by the Friedman test. The level of significance was p = 0.05. RESULTS: We found larger stability about all three axes of movement analyzed for the PLATE than the crossed screws osteosynthesis (CSO). The Friedman test showed statistical significance at a level of p = 0.05 for all groups and both translational and rotational movements. CONCLUSION: The results of our study confirm that the fixation of the lateral proximal first metatarsal displacement osteotomy with a locking plate fixation is a technically simple procedure of superior stability.

Posttraumatic impingement syndrome of the ankle--indication and results of arthroscopic therapy.

BACKGROUND: Persisting pain after an ankle sprain is often caused by the development of intraarticular fibrous scars or even tibiotalar spurs due to repetitive trauma. This may result in a posttraumatic impingement syndrome of the ankle. Pain is typically provoked by dorsiflexion of the ankle and palpation of the tibiotalar anterior joint space. The study evaluates the outcome of arthroscopic treatment of the ankle impingement syndrome. METHODS: 32 patients are included (16-65 years, mean age 38 years) who underwent an arthroscopic operation because of an impingement syndrome of the ankle grades I-III (Scranton) due to a trauma without therapeutic response to conservative therapy over 3 months. Diagnostic criteria were palpatoric anterior ankle joint pain and pain provoked by dorsiflexion, in cases of grades II and III lesions spurs on the X-ray as well. The mean follow-up time was 49 months. The evaluation of the results was done with the West Point Ankle Score. The study is designed as a retrospective case series. RESULTS: 26 patients reached more than 80 points in the West Point Ankle Score corresponding to a good or excellent result (mean result 86 points, ranging from 80 to 98 points). The preoperative mean score reached up to 64 points overall (57-70). Five patients rated the postoperative result fair, one bad with 73 points at mean (62-78). Preoperatively they reached 56 point on an average (48-62). The fair and the poor results were associated with severe ankle sprain leading to ligament ruptures or fractures where severe chondral lesions were to be found with arthroscopy. CONCLUSIONS: The results of the study show that ankle arthroscopy with resection of hypertrophic synovium and fibrous bands (type I) or tibial spurs (types II and III injuries) after an ankle sprain haven proven to be a reliable therapy for a posttraumatic impingement syndrome of the ankle that does not respond to conservative treatment. It is characterized by low morbidity and good to excellent results in most cases. The outcome of arthroscopic treatment was related to the extent of chondral lesions.

Digital stereophotogrammetry based on circular markers and zooming cameras: evaluation of a method for 3D analysis of small motions in orthopaedic research.

BACKGROUND: Orthopaedic research projects focusing on small displacements in a small measurement volume require a radiation free, three dimensional motion analysis system. A stereophotogrammetrical motion analysis system can track wireless, small, light-weight markers attached to the objects. Thereby the disturbance of the measured objects through the marker tracking can be kept at minimum. The purpose of this study was to develop and evaluate a non-position fixed compact motion analysis system configured for a small measurement volume and able to zoom while tracking small round flat markers in respect to a fiducial marker which was used for the camera pose estimation. METHODS: The system consisted of two web cameras and the fiducial marker placed in front of them. The markers to track were black circles on a white background. The algorithm to detect a centre of the projected circle on the image plane was described and applied. In order to evaluate the accuracy (mean measurement error) and precision (standard deviation of the measurement error) of the optical measurement system, two experiments were performed: 1) inter-marker distance measurement and 2) marker displacement measurement. RESULTS: The first experiment of the 10 mm distances measurement showed a total accuracy of 0.0086 mm and precision of ± 0.1002 mm. In the second experiment, translations from 0.5 mm to 5 mm were measured with total accuracy of 0.0038 mm and precision of ± 0.0461 mm. The rotations of 2.25° amount were measured with the entire accuracy of 0.058° and the precision was of ± 0.172°. CONCLUSIONS: The description of the non-proprietary measurement device with very good levels of accuracy and precision may provide opportunities for new, cost effective applications of stereophotogrammetrical analysis in musculoskeletal research projects, focusing on kinematics of small displacements in a small measurement volume.

[The Akin procedure as closing wedge osteotomy for the correction of a hallux valgus interphalangeus deformity]. / Die Korrektur des Hallux valgus interphalangeus durch Closing-Wedge-Osteotomie nach Akin.

OBJECTIVE: Realignment of the great toe in the case of a hallux valgus interphalangeus by means of a medially based closing wedge osteotomy. INDICATIONS: Hallux valgus interphalangeus deformity, characterized by an enlarged distal articular surface angle (> 10 degrees). Correction of a hallux valgus interphalangeus deformity as an additional procedure in the case of hallux valgus surgery. CONTRAINDICATIONS: Incongruent first metatarsophalangeal joint with lateral subluxation of the proximal phalanx. Isolated procedure to correct hallux valgus deformity. Lack of patient compliance. Neurovascular disturbance of the forefoot. SURGICAL TECHNIQUE: Medially based closing wedge osteotomy of the proximal phalanx to reduce the distal articular surface angle. Fixation with a lag screw, cannulated Herbert screw, memory cramp, threaded Kirschner wire, or interosseous suture. POSTOPERATIVE MANAGEMENT: Wound dressing to assure the position of the great toe. Radiographic documentation of the forefoot in two planes. Strict elevation of the operated foot to prevent postoperative swelling. Mobilization of the patient with a forefoot relief orthosis, until consolidation of the osteotomy is verified radiologically (4-5 weeks). Low-molecular-weight heparin for at least 1 week. Hallux valgus bandage or functional taping for 6 weeks postoperatively in patients with additional metatarsal osteotomy. RESULTS: Clinical and radiologic follow-up based on 32 patients showed good results. The postoperative Hallux Score of the American Orthopaedic Foot and Ankle Society improved to 89 points.