Purpose: Posterior instability of the shoulder requires surgical treatment in involuntary forms and after failure of functional treatment. As for anterior instability, a bone block can be fashioned from an iliac graft or a pediculated graft harvested from the acromion. This retrospective analysis concerned the results obtained in eighteen consecutive cases.

Material and methods: This series included ten men and eight women, mean age 26 years (15–42) at time of surgery. Fourteen (77%) practised sports activities including four at competition level. Symptoms had persisted for four years on the average. For three patients (16%) posterior instability was expressed by recurrent luxation subluxation. For nine patients (50%) posterior subluxation was a common involuntary event. Six patients suffered from painful shoulders due to an unrecognised posterior instability accident. Diagnosis of posterior instability was establised by arthroscopy in seven patients (39%). For nine shoulders the intervention consisted in a screwed posterior iliac block associated with a tension procedure on the capsule (group 1). For the other nine shoulders the block was harvested from the acromion and pediculated on the deltoid (group 2).

Results: Mean follow-up for all patients was eight years. The Duplay score was 75 points at last follow-up. Twelve patients (85% of the athletes) were able to resume their sports activities, half at the same level. Nine patients were pain free. Six patients (33%) had persistent apprehension but did not present true recurrence at physical examination. The Duplay score was 69.4 points in group 1 (follow-up 12 years) and 82.2 points in group 2 (follow-up three years). Thirteen patients (77%) did not have any sign of joint degeneration at last follow-up. One patient had advanced stage IV degeneration related to an intra-articular screw. All patients felt their shoulder had been improved by surgery and one third were disappointed with the results.

Discussion: Use of a posterior block is an effective treatent for posterior instability giving results comparable with those obtained with anterior blocks in terms of shoulder stability, pain, recovery of motion, and subjective outcome. This procedure favours joint degeneration less than anterior stabilisation. Results obtained with pediculated acromial blocks are encouraging.

Purpose: The purpose of this study was to evaluate the sensitivity and specificity of magnetic resonance imaging (MRI) in the diagnosis of medial and lateral meniscal injury in operated and non-operated knees.

Material and methods: This prospective longitudinal study was conducted between January 1st 1995 and December 31st 1997. Each patient had a physical examination, a standard radiography study, and an MRI and an arthroscopy. The MRI was performed with two machines running at 1.5 Tesla and 0.5 Tesla. Spin-echo T2 slices were obtained in the saggital plane, and spin-echo fat saturation slices in the frontal and axial planes. Arthroscopy was performed and/or controlled by the same operator.

Results: The protocol included 132 patients. Ten patients (ten knees) had another arthroscopy after arthroscopic meniscectomy. Mean time between the physical examination and MRI was 57 days, it was 69 days between MRI and arthroscopy. Sensitivity, specificity, positive predictive value, negative predictive value and precision were, respectively, 94.8%, 61.%, 86.7%, 81.5% and 85.6% for the medial meniscus and 73%, 93.3%, 76% 93.5% and 90.1% for the lateral meniscus.

Discussion: Arthroscopy remains the gold standard for prospective comparative studies (Reigher 1986, Jackson 1988, Kelly 1991). MRI is the examination of choice for the diagnosis of meniscal injury in non-operated knees (Polly 1988). Most false positives concern injuries located on the posterior part of the medial meniscus. For radiologists (Mink 1988), these false negatives would result from poor analysis by the arthroscopic surgeon (Quinn 1991). Arthroscopists point out that radiologists overestimate injuries of the posterior segment (Barronian 1989, Fischer 1991, Spiers 1994). These false negatives involve the lateral meniscus (Cheung 1997). Our study corroborates the results reported in the literature. For repeated arthroscopies, no conclusion can be drawn from the interval of confidence observed in a population of ten knees. Nevertheless, in these knees, the MRI provided a good means of identifying recurrent lesions of both the medial and lateral menisci.

Conclusion: The physical examination provide a strong clue to meniscal injury in non-operated knees, so it is not necessary to perform an MRI before arthroscopy In all other cases, particularly there is recurrence, MRI can identify injury to the medial or lateral menisci with good sensitivity and specificity. In most cases, if the MRI is negative, it is not necessary to perform arthroscopy to search for a meniscal injury.

Purpose: Despite the development of new imaging techniques (MRI, CT scan) longitudinal studies of total hip arthroplasty (THA) are still conducted with conventional radiographs. New techniques for conventional radiograpy such as luminous screens with memory raise the question of longitudinal study in patients with THA where the new screen-film might produce artefacts.

Material and method: This prospective study examined intermethod and interobserver agreement. Thirty-seven patients were included in the series from July 1st, 1998 and September 30, 1998. Each patient had a double radiography series: three plain films using the conventional technique (C) and three digitalized screen films (D). The C were taken with a 1/1 ratio on a Philips Diagnost 90 table and developed using the Kodak M6 method using a 36 x 43 cm cassette for the pelvic x-ray and a 24 x 30 cm cassette for the x-ray of the prosthetic hip. The D were made on the Philips Diagnost 90 table and developed with the Agfa ADC70 procedure on a memory screen with a 5 pl/mm spatial resolution for 36 x 43 cm for the pelvic x-ray and 28 x 35 for the prosthetic hip. The same operator performed the complete radiography series in the same patient (C and D). The images were read examining the cement/bone interfaces and the prosthesis/cement interfaces looking for the classical radio-lucent lines in the De Lee and Charnley sectors. The presence and the thickness of the radiolucent line were classed in three groups: no line, line less than 2 mm, line greater than 2 mm. For each patient, the films were placed in anonymous folders and two subgroups were selected at random for the readers (a radiologist and an orthopaedic surgeon) who did not read successively the same films for the same patient. The results were recorded with an Excel data sheet and the statistical analysis was done with the BMDP software.

Results: Thirty-seven patients were included (22 women and 15 men) with 40 THA. Mean age was 64 years (42–86). Mean follow-up of the THA was 25 months (2–248). Four patients had mechanical pain or deceased joint amplitude and 33 patients had no clinical sign. Only one lucent line was found measuring less than 2 mm in the 1st quadrant of the cup and the 3, 4, and 5 zones on the AP view and the 10, 11, 12 zones on the lateral view on the tail of the pros-thesis. In this study, the kappa value was less than 0.5 for the mean concordance according to the Landis and Koch classification. The Kappa was higher for the intermethod analysis irrespective of the reader, than for the interobserver analysis.

Discussion, conclusion: Independent readers of the two types of images (C and D) did not demonstrate any difference for cemented or noncemented prosthesis in a longitudinal study of THA. The reproducibility between the C and D techniques was small. However, our study only analysed a few of the numerous radiographic signs considered to favour loosening (stress shielding, lucent lines etc.…). However, the analysis of the Kappa results demonstrated mean concordance between the techniques better than mean concordance between observers.