Reproducibility of X-rays and CT arthrography in SLAC, SNAC, SCAC wrists.

The purpose of this study was to assess the inter-observer and intra-observer reproducibility of the interpretation of CT arthrography and plain X-rays for scapholunate advanced collapse (SLAC), scaphoid non-union advanced collapse (SNAC) and scaphoid chondrocalcinosis advanced collapse (SCAC) wrist conditions, as well as the clinical relevance of these imaging modalities. The CT and X-rays images were reviewed twice in a blinded and randomized manner by two experienced orthopedic surgeons specialized in hand surgery, two orthopedic surgery residents and two experienced radiologists specialized in bone and joint imaging. Cohen's kappa and Fleiss' kappa coefficients were used to analyze the reproducibility of interpretation of the radiological examinations. With CT arthrography, the overall diagnosis was often a problem, in terms of both inter- or intra-observer reproducibility. The assessment of the joint line appeared to be fairly reproducible for each observer but was poorly reproducible between different observers. Plain X-rays are not sufficient to assess cartilage quality in degenerative wrist disease. CT arthrography is a reliable examination, but its interpretation is not always standardized. Diagnostic arthroscopy may be justified in doubtful cases.

Risk of sural nerve injury during lateral distal Achilles tendinoscopy: a cadaver study.

BACKGROUND: The risk of damage to cutaneous sensory nerves located near portals has been evaluated for both conventional arthroscopy and extra-articular posterior ankle endoscopy. The objective of the anatomic study reported here was to assess the risk of injury to the sural nerve or lateral calcaneal nerve while using the distal lateral portal for the Achilles tendinoscopy procedure described by Vega et al. in 2008. MATERIALS AND METHODS: We dissected the sural nerve and its branch, the lateral calcaneal nerve, of 13 human cadaver ankles in the prone position. We defined P as the point where the Achilles peritendon was opened during the distal lateral approach used for the study technique. P was adjacent to the lateral edge of the Achilles tendon, 2 cm proximal to the postero-superior edge of the calcaneal tuberosity. T was defined as the attachment site of the most lateral fibres of the Achilles tendon to the postero-superior edge of the calcaneal tuberosity. We evaluated the origin of the lateral calcaneal nerve relative to T and we measured the shortest distances separating P from the sural nerve and lateral calcaneal nerve. RESULTS: A lateral calcaneal nerve was identified in 10 (77%) ankles and originated a mean of 39.1mm (range, 25.0-65.0mm) proximal to T. P was at a mean distance from the sural nerve of 12.3mm (range, 5.0-18.0mm) and from the lateral calcaneal nerve of 6.8mm (range, 4.0-9.0mm). The median difference between these two distances was statistically significant (P=0.002). DISCUSSION: While using the distal lateral portal for Achilles tendinoscopy, the lateral calcaneal nerve is at greater risk for injury than is the sural nerve. LEVEL OF EVIDENCE: Level IV. Anatomic Study.

Cruciate-sacrificing total knee arthroplasty and insert design: A radiologic study of sagittal laxity.

INTRODUCTION: Ultracongruent inserts avoid some of the drawbacks of central spine postero-stabilized inserts. However, early wear has been reported, and may be due to increased sagittal laxity. The principal objective of the present study was to compare sagittal laxity in rotating platform total knee replacements (TKR) according to insert design: ultracongruent versus central spine. The principal hypothesis was that insert design influences global sagittal laxity. MATERIAL AND METHODS: A retrospective comparative study recruited 3 consecutive series of patients treated for primary osteoarthritis of the knee, with a minimum 1 year's follow-up. The UC series comprised 35 knees in 34 patients, receiving a Total Knee Triathlon™ (Stryker Orthopaedics, Mahwah, NJ) TKR with ultracongruent insert, at a mean 2.0 years' follow-up. The UC+ series comprised 36 knees in 34 patients, receiving the BalanSys™ (Mathys Ltd, Bettlach, Switzerland) TKR with ultracongruent insert, at a mean 2.5 years' follow-up; in this model, the anterior edge of the insert is higher than in the UC series ("deep-dish" design). The PS series comprised 43 knees in 40 patients, receiving a Total Knee Triathlon™ (Stryker Orthopaedics, Mahwah, NJ) TKR with central spine posterior stabilization, at a mean 1.5 years' follow-up. The principal assessment criterion was sagittal laxity at 90° flexion as measured by the Telos Stress Device® (Metax GmbH, Hungen, Germany). RESULTS: Sagittal laxity did not significantly differ between the UC and UC+ series: mean 8.2mm (range: 0-19.5mm) and 8.4mm (4.5-15.8mm), respectively. Sagittal laxity in the PS series was significantly less: 1.4mm (0.2-3.9) (P<0.0001). CONCLUSION: Sagittal laxity was greater in ultracongruent than central spine posterior stabilized TKR. This anteroposterior movement may induce polyethylene wear. The ideal degree of sagittal laxity for ultracongruent inserts remains to be determined. LEVEL OF EVIDENCE: IV - retrospective study.

Mid-term outcomes after distally locked-to-standard primary stem exchange in 29 hip-prosthesis patients.

BACKGROUND: Cementless locked femoral stems are used for revision surgery in patients with bone loss to induce spontaneous bone reconstruction, allowing subsequent replacement by a standard primary stem. The small number of patients and short follow-ups available to date preclude a valid assessment of this strategy. HYPOTHESIS: After distally locked stem revision, replacement by a standard primary stem does not induce complications, and the quality of the bone reconstruction allows strong fixation of a regular primary stem. MATERIALS AND METHODS: We retrospectively evaluated 29 patients in whom a distally locked femoral stem was replaced by a standard primary stem between 1998 and 2010 (cemented in 27, cementless in 2 cases). The reason for the procedure was stem breakage, stem migration, or thigh pain. Mean patient age was 63 years (range, 39-78 years). Outcomes were evaluated based on the Postel-Merle d'Aubigné [PMA] score and Harris Hip Score [HHS]. In addition, radiographs were obtained to assess prosthesis fixation and the Hofmann cortical index measured the bone reconstruction. RESULTS: The distally locked stem was removed via a postero-lateral approach without femoral osteotomy in all the 29 cases. In one patient, an intra-operative fracture occurred during femoral preparation. Mean follow-up after the exchange procedure was 75 months (range, 3-188 months). Postoperative ccomplications occurred in 9 (32%) patients and consisted of chronic infection in 2 patients (after 3 and 76 months), post-traumatic peri-prosthetic fractures treated with internal fixation in 3 patients (after 100, 138, and 182 months), aseptic loosening in 3 patients (after 13, 39, and 122 months), and recurrent instability in one patient (after 63 months). All cause revision stem survival after 75 months was 72% (95% confidence interval, 47%-87%). In the 19 patients who still had their revision stem at last follow-up, the mean PMA score was 16.7 (range, 13-18) and the mean HHS was 88.2 (range, 59-99). The Hofmann index remained unchanged [36.5% (range, 28%-58%) before the exchange and 32.9% (range, 20%-57%) after the exchange; P=0.129]. DISCUSSION: This study confirms the feasibility of substituting a distally locked stem with a standard primary stem. No specific complications occurred and no technical difficulties arose when extracting the long stems. However, the 32% complication rate and, more specifically, the occurrence of loosening in 10% (3/29) of patients mandates caution in the use of this technique, which should not be proposed routinely, and suggests a need for considering cementless fixation of the standard primary stem. LEVEL OF EVIDENCE: Level IV, retrospective study.