Biomedical subjects

M S Schickendantz

Publications and source records attributed to M S Schickendantz.

9 recordsLinked to original sources

PubMed1999

MR imaging of the thrower's shoulder. Internal impingement, latissimus dorsi/subscapularis strains, and related injuries.

In conclusion, internal impingement apparently occurs in nearly all patients and is demonstrable on MR imaging. Pathologic changes associated with internal impingement seem to develop with repetitive placement of the arm into a position of extreme external rotation and abduction. Findings may include lesions of the posterior superior labrum, undersurface irritation, or tearing of the supraspinatus-infraspinatus junction near the attachment site and cystic changes of the posterior superior glenoid and posterior lateral greater tuberosity. There is no evidence for a particular sequence of pathologic changes. Instability may be associated with but does not appear to be a prerequisite for the development of the pathologic lesions of internal impingement.

Adult↗

PubMed1995

Biomechanical analysis of canine bone lengthened by the callotasis method.

The mechanical integrity of tibial bone treated by distraction osteogenesis (callotasis) using an Orthofix external fixator was evaluated in a group of 6 dogs. Diaphyseal corticotomies were performed on Day 0. Distraction was begun on Day 8, at a rate of 0.33 mm every 8 hours. On Day 34, the Orthofix frame was locked. On Day 56, the frames were removed and the dogs were euthanized. Radiographs were taken weekly to assess regenerate bone formation and extent of tibial bone lengthening, which averaged 12 mm (range, 5-20 mm). One dog showed incomplete bony union that was attributed to pin loosening. Torsional testing of lengthened and contralateral control tibiae resulted in spiral diaphyseal fractures. Five of 6 lengthened tibiae bones fractured within the diaphysis, but outside the regenerate area, suggesting that the strength of the lengthened segment exceeded that of the original diaphysis which was exposed to stress shielding by the external fixator. These observations have led to a method to test and evaluate lengthened bone at the time of frame removal and to monitor the effectiveness of this type of technique.

Animals↗

PubMed1995

Operative treatment of nonunion of surgical neck fractures of the humerus.

Seventeen patients who had undergone operative treatment for painful nonunion of a surgical neck fracture of the proximal humerus were evaluated an average of 6.3 years (range, 2-11 years) from the time of surgery to determine clinical and radiographic outcome. Ten patients underwent open reduction and internal fixation with tension band wiring and Rush rods, and 7 underwent proximal humeral hemiarthroplasty. The average age of the patients was 60 years old. After surgery, pain, function, and range of motion improved for both groups. University of California Los Angeles scores improved from an average of 4.4 to 22 points in the internal fixation group and from 4.8 to 21.4 in the hemiarthroplasty group. All 17 patients were eventually able to perform activities of daily living independently. No patient in either group was able to return to his or her preinjury level of work. Nonunion persisted in 2 patients who had undergone internal fixation, and avascular necrosis developed in 2 others. Eight of 10 patients in the internal fixation group required removal of the Rush rods for treatment of symptomatic mechanical impingement. Painful nonunion of a surgical neck fracture of the proximal humerus is a difficult problem to manage operatively. Pain relief and functional improvement was similar in patients who underwent either procedure. However, 11 of 17 patients had fair or poor ultimate outcomes.

Activities of Daily Living↗

PubMed1993

Results of nonoperative management of full-thickness tears of the rotator cuff.

The results of nonoperative management of 53 patients with full-thickness tears of the rotator cuff proven by arthroscopic examination was as follows. Patients were treated with nonsteroidal antiinflammatory medication, stretching, strengthening, and occasional steroid injections. Average age at presentation was 62.2 years. Patients were evaluated at an average of 7.6 years. Forty patients were male, and the dominant limb was involved in 40 cases. Thirty-four patients were reviewed by questionnaire and physical examination, whereas 19 patients were evaluated by telephone interview only. In 40 patients, the onset of symptoms was associated with an injury. In 12 patients, workmen's compensation was involved. At follow-up evaluation, the 34 shoulders that were available for examination were evaluated for pain, range of motion, strength, and function. Thirty-nine of the 53 patients (74%) assessed subjectively had only slight or no shoulder discomfort. Of the 28 shoulders presenting within three months of injury, 24 (86%) were rated as satisfactory at the time of latest evaluation. Of the 16 patients who initially had had shoulder pain for over 6 months, only nine (56%) were rated as satisfactory. Most patients showed improvement with regard to their ability to perform activities of daily living. Average active total elevation was 149 degrees compared with 121 degrees at initial presentation. Thirty-two of the 34 patients examined (94%) had evidence of weakness on muscle testing and 19 (56%) had demonstrable muscle atrophy.

Activities of Daily Living↗

PubMed1992

A model for evaluating the strength of bones lengthened by distraction osteogenesis.

In an effort to evaluate the strength of bones lengthened by distraction osteogenesis, a modified Ilizarov-type external fixator was applied to the right tibiae of five adult mongrel dogs. Diaphyseal corticotomies were performed, and distraction (lengthening) was carried out at a rate of approximately 1 mm per day for 20 days. After completion of the lengthening, the animals were killed, the fixators were removed, and the right and left tibiae were harvested and stripped of soft tissue. The ends of all harvested bones were fixated in polymethylmethacrylate to allow testing on a materials testing system (MTS) machine. Testing under torsional loads was performed on the MTS machine (50 degrees maximum angle of rotation at ten seconds) until failure. The right tibiae were lengthened an average of 12 mm (range, 7-15 mm). The slopes of the linear portion of the torque versus rotation curves were determined. A comparison of slopes revealed a mean change in stiffness between test and control bones of 20.32% (range, 0.64%-40.5%). All tibiae exhibiting mature regenerate bone demonstrated stiffness greater than the matched controls (range, 0.64-24.09% stiffer). Four of five dogs had problems with proximal and distal ring impingement. This study presents a reproducible model for evaluating the strength of bones lengthened by distraction osteogenesis. The lengthened bones that exhibited bony or mature regeneration were as strong as the control bones.

Animals↗

PubMed1990

Mycobacterial prepatellar bursitis.

Prepatellar bursitis secondary to infection with an atypical mycobacterium developed in an 88-year-old man. A review of all previously reported cases in the English literature indicates tuberculosis is important in the differential diagnosis of prepatellar bursitis.

Aged↗

PubMed1990

The incorporation of tibial allografts in total knee arthroplasty.

Twelve knees in ten patients had revision total knee replacement with insertion of an allograft for a large tibial defect. The knees were retrospectively evaluated at an average of thirty-two months (range, twenty-five to fifty-one months) by clinical examination, radiography, planar bone scintigraphy, and single-photon-emission computed tomography. The average age of the patients was sixty-two years (range, fifty-four to seventy-nine years). A constrained total-condylar prosthesis was used for all revisions. A contained tibial defect was present in five knees, and seven knees had an uncontained defect that was treated with a massive composite structural allograft, five of which were secured with internal fixation. The knee scores improved from an average of 51 points before operation to an average of 87 points post-operatively. Seven knees had a score of 85 points or more and were considered to have an excellent clinical result. Two knees had a good result, with scores of 77 and 72 points. One knee had another revision because of painful non-union of a medial structural graft, and the result in that knee was considered a failure. The average range of motion improved from 84 degrees to 105 degrees. There were no deep infections, and no graft showed evidence of fracture or collapse. Radiographs demonstrated complete incorporation of the graft in eleven of the twelve knees at an average of twenty-three months after operation. Single-photon-emission computed-tomography scans showed uniform activity in the area of the graft in four of the five knees that were studied.

Aged↗

PubMedDate not supplied

Axillary nerve injury after thermal capsular shrinkage of the shoulder.

The purpose of this study was to evaluate 4 cases in which axillary nerve injury was observed after radiofrequency capsular shrinkage of the shoulder. These cases were used to evaluate the clinical circumstances under which axillary nerve injury occurred, the time frame over which these injuries recovered, and the ultimate outcome observed in these patients. The case histories of each of these 4 patients were carefully evaluated. In 2 of the 4 cases, purely sensory findings were found, and in 2 cases both sensory and motor injuries occurred. In each case the inferior axillary recess was treated using the Oratech Interventions Tac-S probe. The authors conclude that injury to the axillary nerve during this procedure is possible and postulate that heat penetration through the capsule to the nerve is the most likely cause of injury.

Adolescent↗

PubMedDate not supplied

The predictive value of radiographs in the evaluation of unilateral and bilateral anterior cruciate ligament injuries.

A review of 250 cases of surgical reconstruction of the anterior cruciate ligament identified 24 patients with bilateral complete tears of the anterior cruciate ligament. Twenty of these patients had previous reconstruction of one anterior cruciate ligament before rupture of the opposite ligament. Twelve injuries occurred during the same activity that was responsible for the initial opposite injury. The average time between surgical reconstruction and rupture of the opposite ligament was 29.3 months (range, 3 to 103). No significant demographic differences existed between patients with unilateral or bilateral ruptures of the anterior cruciate ligament. Standardized measurements of intercondylar notch height and width and medial and lateral femoral condyle height and width were performed on routine notchview height and width were performed on routine notchview radiographs of 31 knees of patients with bilateral injuries, 30 with unilateral injury, and 30 with no anterior cruciate ligament injury. Statistical analysis revealed no significant differences between the three groups when comparing absolute measures or any of eight mathematical ratios calculated from these measurements. We concluded that measurements of the intercondylar notch made from radiographs may not be reliable predictors of injury to the anterior cruciate ligament. We found no significant clinical or demographic differences between patients with unilateral or bilateral complete ruptures of the anterior cruciate ligament.

Adolescent↗