Spontaneous osteonecrosis of the knee (SON) is an osteonecrosis that mainly affects the medial femoral condyle. In endstage SON, knee arthroplasty is the therapy of choice. Because of the unicompartimental nature of the knee, unicondylar knee arthroplasty is considered an ideal implant for treatment of this condition. The purpose of this study was to prove that the long-term results of unicondylar implants are better than the results of bicondylar implants for the treatment of SON. All patients treated for SON between 1984 and 2000 have been recorded. Two groups were formed according to the implant used. In all patients the preoperative radiograph was analyzed according to stage and size of the osteonecrotic lesion and the osteoarthritic changes. Postoperatively, the Knee Society Score and the radiograph were recorded. Thirty-nine patients were included in this study, of which 23 patients were treated by a unicondylar implant and 16 by a bicondylar implant. On a short-term basis, unicondylar implants had better clinical results; however, on a long-term basis bicondylar implants were better. In comparison, only unicondylar implants had to be revised. Radiolucency lines were mainly observed in patients with unicondylar impants and large areas of osteonecrosis. Our long-term results suggest that patients with SON are better treated by bicondylar implants. The reasons for the higher failure rate for unicondylar implants are poor bone stock and secondary arthritic changes.

Evaluation of patient activity is essential for clinical decision making before THA. To correlate age progression to patient activity after THA, we determined the number of walking cycles of 105 patients in different age groups by decades. Patients on average performed 6144 walking cycles per day (2.24 million cycles per year). Men were more active than women. The highest activity occurred in patients between 50 and 59 years of age, with a constant decrease in activity with advancing age. However, within age groups, we observed up to sixfold differences in the number of walking cycles per day. In addition to declining activity with advancing age, higher body mass index correlated with lower step counts. The high mean measured number of walking cycles, which were even higher than those reported for subjects without an arthroplasty, suggests patients benefit from THA. Female gender, advanced age, and obesity correlated with lower activity. Owing to the high intragroup variability of our results, preoperative evaluation of patient activity levels, individual patient factors, and patient demands, should be considered in clinical practice.

In a prospective clinical trial, first the German Short Musculoskeletal Function Assessment questionnaire (SMFA-D) was tested for reliability, validity, and responsiveness in 23 patients with rotator cuff tears, and secondly the Short Form (SF)-36, and the Constant score were evaluated comparatively in 45 patients with rotator cuff tear undergoing open repair. Retest reliability was excellent for the functional index of the SMFA-D and satisfactory for the bother index. The SMFA-D showed good validity and responsiveness. All three instruments demonstrated significantly the positive effect of rotator cuff repair at 12-month follow-up. Using comparable scales, effect sizes were bigger with the SMFA-D than with the SF-36 and as big as the Constant score. Significant correlations of the SMFA-D indices with the SF-36 scales and the Constant score could be shown preoperatively. At 12-month follow-up, all correlations between SMFA-D indices, SF-36 scales, and Constant score function scales were still significant. We recommend use of the SMFA-D to assess changes in functional status concerning patients with rotator cuff tear undergoing open repair.

Objective: The patient-based evaluation of outcome is gaining increased importance. The aim of the study was to demonstrate the reliability, validity and responsiveness of the German version of the Short Musculoskeletal Function Assessment Questionnaire (SMFA-D) in patients undergoing surgical or conservative treatment. Methods: Three hundred and thirty-two patients suffering from osteoarthritis of the hip or knee, rheumatoid arthritis or rotator cuff tear undergoing surgical or medical inpatient treatment were followed up for 12 month. Patients underwent both SMFA-D and other assessments and clinical as well as radiological examinations. Reliability, validity and responsiveness of the SMFA-D were evaluated. Results: Values of the SMFA-D subscales, Function index (M 22-49, SD 12-20, range 0-96) and Bother index (M 29-52, SD 15-23, range 0-100), showed a normal distribution. Internal consistency (0.88-0.97) and retest reliability (0.71-0.96) coefficients were satisfactory to excellent. In most cases, the SMFA-D correlated significantly with function tests, physicians' function ratings, patients' pain ratings and other quality-of-life questionnaires in all patient subgroups. The results support both the construct and criterion validity of the measure. Different patient groups and subgroups could be discriminated with the SMFA-D scales. The standardized response means of SMFA-D subscales were in surgical patients better than in conservatively treated patients and comparable to those of the SF-36 Physical Component Summary scale. Conclusions: The German version of SMFA is a reliable, valid and responsive questionnaire in patients with osteoarthritis of the hip or knee, rheumatoid arthritis or rotator cuff tear undergoing surgical or medical inpatient treatment. Thus, the use of the SMFA-D in these patients can be recommended.

The aim was to develop a German questionnaire for self-assessment of shoulder function equivalent to the Constant-Score (CS). To evaluate the retest reliability, the CS questionnaire was completed twice within 1 week by 47 patients prior to shoulder surgery. For validation the CS was assessed by the physician after the second self-test. The medium selectivity of the CS questionnaire at hospital admission was 0.47, the medium item difficulty 0.40, the test-retest reliability 0.675 ( p=0.000), the internal consistency of the questionnaire 0.80, and of the physician's CS evaluation 0.85. Construct, content, and discriminative validity of the questionnaire could be demonstrated. A high correlation of the patient-based questionnaire with the physician-assessed CS was found ( p=0.82). The statistical analyses demonstrated that the CS questionnaire is a reliable and valid instrument to evaluate the CS and can therefore be used for follow-up studies.