With the exception of the Hill-Sachs interval, CT and MRI show no significant differences in the diagnostic value of the HSL measurement regardless of the measurement technique.

PURPOSE: The aim of the current study was to compare the diagnostic precision and reliability of different methods in measuring Hill-Sachs lesions (HSLs) using MRI and CT. METHODS: A total of 80 consecutive patients with a history of anterior shoulder instability were retrospectively included. The preoperative CT and MRI scans of the affected shoulders were analysed. To investigate the ability of the Franceschi grading, Calandra classification, Richards, Hall, and Rowe grading scale, Flatow percentage and "glenoid track" assessment according to Di Giacomo et al. to quantify the extent of humeral bone loss, the results of each measurement method obtained with MRI were compared with those achieved with CT. In addition, the intra- and inter-rater reliabilities of each measurement method using CT and MRI were calculated and compared. RESULTS: A significant difference was found between CT and MRI in the determination of the Hill-Sachs interval (HSI) (p = 0.016), but not between the results of any of the other measurement techniques. With the exceptions of the Franceschi grade and Calandra classification, all measurement methods showed good or excellent intra- and inter-rater reliabilities for both MRI and CT. CONCLUSIONS: While the determination of the HSI with MRI was more accurate, all other analysed techniques for measuring the amount of humeral bone loss showed similar diagnostic precision. With regard to the intra- and inter-rater reliabilities, all measurement techniques analysed, with the exception of the Franceschi and Calandra classifications, provided good to very good reliabilities with both CT and MRI. LEVEL OF EVIDENCE: III.

[Linked Prosthesis for the Proximal Interphalangeal Joint: 17-Year Long-Term Results]. / Gekoppelte Fingermittelgelenksprothese - Verlauf über 17 Jahre.

BACKGROUND/PURPOSE: Joint replacement is a widely used procedure to treat painful osteoarthritis of the proximal interphalangeal joint. From 1996 to 1999, 16 patients received 19 hinged, piston-based DIGITOS prostheses in our department. In 2007, the 7-year clinical course of 14 patients (17 devices) was published in this journal. Now 12 of these patients (15 devices) have been followed with an average history of 17 years, and the preoperative data has been compared with the results after 7 and 17 years, respectively. PATIENTS AND METHODS: The patients were 10 women and 2 men, whose average age at the time of the preoperative examination was 63 (48-69) years. Replacements were performed on the index (6), middle (6), and ring finger (3). There were 14 idiopathic osteoarthritic changes and 1 posttraumatic osteoarthritic change. Follow-up included a clinical (range of motion in the proximal interphalangeal joint, extension lag, pain) and radiological examination. In addition, the DASH score was obtained and the patients were asked whether or not they would undergo the same surgery again. The results after 7 and 17 years were reviewed for statistically significant differences. RESULTS: While there were significant changes regarding extension lag and flexion in the first 7 years after replacement of the proximal interphalangeal joint, only minor changes were observed between 7 and 17 years after surgery. While the prosthesis was in its correct position in the first 2 years after implantation, all prostheses exhibited radiolucent lines after 4 years and periprosthetic osteophytes after 5 years. 17 years after surgery, the radiolucent lines had not increased at all and the osteophytes had increased insignificantly compared with the 7-year findings. None of the patients reported pain; all of them said that they would undergo the same surgical procedure again. CONCLUSION: While there were significant clinical and radiological changes in the first 7 years after replacement of the proximal interphalangeal joint by a linked DIGITOS prosthesis, only minor changes were observed between 7 and 17 years after surgery.

[Osteoarthritis of the knee in the young patient--who should receive total knee arthroplasty and who should not?]. / Die Gonarthrose des jüngeren Patienten--wen sollte man knieendoprothetisch versorgen, wen nicht?

The incidence of total knee arthroplasty in young patients continues to rise in certain countries despite evidence of decreased patient satisfaction and increased likelihood for revision in patients 55 years of age or less. As long as sufficient pain relief and functional improvement can be obtained by alternative means, total knee arthroplasty should be avoided whenever possible. In young patients with unicompartmental osteoarthritis, and a partially conserved joint space, correctional osteotomy around the knee accompanied by cartilage surgery should be preferred in the presence of the respective deformity. In cases of advanced unicompartmental arthritis, unicompartmental arthroplasty should be considered even in younger patients. Only if advanced arthritic changes in more than one compartment or accompanying tibiofemoral instability are present in younger patients, is total knee arthroplasty indicated in selected cases. The strongest predictor of satisfaction even in younger patients is, however, a realistic expectation about the outcome of surgery.

Evaluation of trochlear dysplasia using MRI: correlation between the classification system of Dejour and objective parameters of trochlear dysplasia.

PURPOSE: Trochlear dysplasia is considered to be one of the major factors causing patellofemoral instability (PFI). Dejour's classification is widely used to assess the severity of trochlear dysplasia. Additionally, in current literature, different quantitative parameters are recommended to distinguish between a normal trochlea and a dysplastic trochlea. In order to achieve a more objective evaluation of the trochlea, the aim of this study was to evaluate whether specific measurements of the femoral trochlea can be assigned to the qualitative classification system of Dejour. METHODS: Transverse MRI T2-weighted scans of 80 knees with symptomatic PFI and varying severity of trochlear dysplasia were classified according to Dejour (type A to D). For all MRI scans, quantitative measurements with parameters as described in the literature were applied. The values were then allocated to Dejour's classification. In addition to the four-grade analysis, two-grade analysis was also performed (Dejour type A against type BCD). Dependent on the cut-off values, specificity, sensitivity and Youden index for each parameter was defined. RESULTS: The allocation resulted in the following distribution: type A trochlear dysplasia n = 25, type B n = 23, type C n = 18 and type D n = 14. In descriptive statistics, none of the measurements proposed in the literature could be assigned to the four-grade classification system of Dejour. For the two-grade analysis at the cut-off, sensitivity ranged from 75 to 86 % and specificity from 76 to 84 % for lateral trochlear inclination, trochlear facet asymmetry and depth of trochlear groove. All other measurements showed a poor sensitivity ranging from 49 to 67 % and specificity from 40 to 72 %. Interobserver and intraobserver repeatability for the measured parameters was fair to moderate (ICC values 0.34-0.58) in high-grade dysplasia (type BCD) and substantial to almost perfect (ICC values 0.71-0.88) in low-grade trochlear dysplasia (type A). CONCLUSION: Quantitative measurements of the femoral trochlea have shown to be of limited value for the assessment of trochlear dysplasia. None of the quantitative measurements of the trochlea on transverse images could be assigned to the four-grade descriptive classification of trochlear dysplasia of Dejour. Additionally, measurements could not be reliably performed in high-grade trochlear dysplasia. However, trochlear inclination, trochlear facet asymmetry and depth of trochlear groove may help to distinguish between low-grade and high-grade dysplasia.

Anatomical reconstruction of the medial patellofemoral ligament in children with open growth-plates.

Recurrent lateral patellar dislocation is a common knee injury in the skeletally immature adolescent. In adults, anatomical reconstruction of the medial patellofemoral ligament (MPFL) is recommended, but due to the open physis, operative therapy in children is more challenging. We present a minimal invasive technique for anatomical reconstruction of the MPFL in children respecting the distal femoral physis. This technical note considers the important fact that the femoral insertion is distal to the femoral physis. Since the importance of an anatomical reconstruction respecting the femoral insertion of the ligament has been proven an insertion proximal of the physis has to be strictly avoided.

The relation of the distal femoral physis and the medial patellofemoral ligament.

PURPOSE: The purpose of this study was to analyse true lateral radiographs of children and adolescents to determine the relation of the origin of the MPFL and the distal femoral physis considering the complex anatomy of the physis. The hypothesis was that the femoral insertion of the MPFL is distal to the growth plate. METHODS: Antero-posterior and true lateral radiographs from PACS computer records of 27 patients with a history of patellofemoral instability were assessed. To determine the femoral origin of the MPFL, the method by Schöttle et al. and the method by Redfern et al. were applied independently. On the anteroposterior radiograph, the distance between the medial most part of the physis and the central part of the physis was measured to quantify the concave curvature of the physis. To cross-reference the femoral insertion of the MPFL onto an ap view, the projected MPFL origin-physis distance was subtracted from the distance between the most medial part of the physis and the central part of the physis. RESULTS: The projected median origin of the MPFL as measured on a lateral radiograph was located 3.2 mm (1.2-5.8 mm) proximal to the physis. The median distance between the most medial part of the physis and the physeal line on the anteroposterior radiograph was 9.9 mm (4.1-12.0 mm). Subtracting the two measured values, the median origin of the MPFL as seen on the ap view was 6.4 mm (2.9-8.5 mm) distal to the femoral physis. CONCLUSION: Considering the concave curvature of the distal femoral physis, it can be assumed that the femoral insertion of the MPFL is distal to the femoral physis. As a too proximal insertion of the graft can cause unintentional tightening of the MPFL in knee flexion, these results have to be considered when performing reconstruction of the MPFL in children and adolescents with open growth plates.

[Reliability of digital measurement of acetabular index in hip dysplasia to the time children start walking]. / Reliabilität der digitalen Messung des AC-Winkels bei der Hüftreifungsstörung an Röntgenaufnahmen zum Gehbeginn.

AIM: An assessment of the reproducibility of the acetabular index on the basis of anteroposterior radiographs of the pelvis was performed in order to rule out residual dysplasia of the hip in the second year of life. METHOD: 51 consecutive patients (41 girls, 10 boys) with congenital dysplasia of the hip (35 bilateral, 16 unilateral) were included. Approximately at the time children started walking (mean age: 13.9 months; range: 10 - 22 months), digitised anteroposterior radiographs of the pelvis were recorded. Acetabular indices were measured bilaterally and blinded by two observers (O1 and O2), then classified according to the normal values of the hip joint described by Tönnis et al. (normal = lower single standard deviation [s], light dysplasia = above single standard deviation [s - 2 s] and severe dysplasie = above double standard deviation [2 s]). O2 repeated a second set of observations 6 weeks after the first. 306 values of the acetabular index (O1: 102 values; O2: 204 values) were statistically evaluated. Reliability was expressed by Pearson's correlation coefficient (PCC) and 95 % confidence interval. The rater agreement of the classification into normal values of the hip joint was calculated with the kappa coefficient. RESULTS: The PCC for intraobserver/interobserver reliability was 0.928/0.875. The 95 % confidence interval for intraobserver reliability was +/- 3.1 degrees and for interobserver reliability - 3.1 degrees /+ 5.9 degrees . A comparison of the first series of measurements by O1 with the series of measurements by O2 presented congruence in 66 of 102 hip joints classified according to the normal values of the hip joint as described by Tönnis. In 36 hip joints the classification was deviant, in 15 the classification differed between normal and s, in 21 between s and 2 s. The kappa coefficient of 0.51 showed moderate interobserver agreement. CONCLUSION: The reproducibility of radiological surveillance in congenital hip dysplasia, approximately to the time children start walking, can be considered as adequate. Correct positioning of the patient and exact definition of radiological landmarks are essential. In spite of good statistical values for reliability, decreasing accuracy in classifying into Tönnis' normal values of the hip joint is seen with increasing degree of dysplasia. In marginal cases, before coming to the decision for operative treatment, a second reading, ideally by the same observer and with a chronological shift, is advisable.