Do less medialized reverse shoulder prostheses increase motion and reduce notching?

BACKGROUND: Cuff tear arthropathy is the primary indication for total reverse shoulder arthroplasty. In patients with pseudoparalytic shoulders secondary to irreparable rotator cuff tear, reverse shoulder arthroplasty allows restoration of active anterior elevation and painless shoulder. High rates of glenoid notching have also been reported. We designed a new reverse shoulder arthroplasty with a center of rotation more lateral than the Delta prosthesis to address this problem. QUESTIONS/PURPOSES: Does reduced medialization of reverse shoulder arthroplasty improve shoulder motion, decrease glenoid notching, or increase the risk of glenoid loosening? PATIENTS AND METHODS: We retrospectively reviewed 76 patients with 76 less medialized reverse shoulder prostheses implanted for pseudoparalytic shoulder with rotator cuff deficiency between October 2003 and May 2006. Shoulder motion, Constant-Murley score, and plain radiographs were analyzed. Minimum followup was 24 months (mean, 44 months; range, 24-60 months). RESULTS: The absolute Constant-Murley score increased from 24 to 59, representing an increase of 35 points. The range of active anterior elevation increased by 61°, and the improvement in pain was 10 points. The gain in external rotation with elbow at the side was 15°, while external rotation with 90° abduction increased by 30°. Followup showed no glenoid notching and no glenoid loosening with these less medialized reverse prostheses. CONCLUSIONS: Less medialization of reverse shoulder arthroplasty improves external and medial rotation, thus facilitating the activities of daily living of older patients. The absence of glenoid notching and glenoid loosening hopefully reflects longer prosthesis survival, but longer followup is necessary to confirm these preliminary observations. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Mechanical properties of glenoid cancellous bone.

BACKGROUND: Loosening of the glenoid component in total shoulder arthroplasty is the main late complication of this procedure; it may be assumed that it is highly dependent on the quality of the glenoid cancellous bone. Very little is known about the mechanical properties of this cancellous bone. The aim of this study was to determine these properties (Young's modulus and strength) as well as bone density in different parts of the glenoid cancellous bone to assess their variations. METHODS: Eleven scapulas were obtained from six fresh-frozen, unembalmed human cadavers. Eighty-two cubic cancellous bone specimens were extracted and tested using a uniaxial compression test; then the specimens were defatted and correlations with bone density were determined. FINDINGS: The study showed significant differences in the mechanical properties with anatomic location and directions of loading. Young's modulus and strength were found to be significantly higher at the posterior part of the glenoid with the weakest properties at the antero-inferior part. Cancellous bone was found to be anisotropic with higher mechanical properties in the latero-medial direction perpendicular to the articular surface of the glenoid. The apparent density was on average equal to 0.29 g/cm(3) with the higher values at the posterior and superior part of the glenoid. Good correlation between apparent density and elastic modulus was found only in the sagittal planes but not in the coronal and axial plane. INTERPRETATION: The mechanical properties determined in this study showed the anisotropy of the glenoid cancellous bone; values of these properties could provide input data for finite element method analyses in shoulder prosthesis designs.

Is visual estimation of passive range of motion in the pediatric lower limb valid and reliable?

BACKGROUND: Visual estimation (VE) is an essential tool for evaluation of range of motion. Few papers discussed its validity in children orthopedics' practice. The purpose of our study was to assess validity and reliability of VE for passive range of motions (PROMs) of children's lower limbs. METHODS: Fifty typically developing children (100 lower limbs) were examined. Visual estimations for PROMs of hip (flexion, adduction, abduction, internal and external rotations), knee (flexion and popliteal angle) and ankle (dorsiflexion and plantarflexion) were made by a pediatric orthopaedic surgeon (POS) and a 5th year resident in orthopaedics. A last year medical student did goniometric measurements. Three weeks later, same measurements were performed to assess reliability of visual estimation for each examiner. RESULTS: Visual estimations of the POS were highly reliable for hip flexion, hip rotations and popliteal angle (rhoc >or= 0.8). Reliability was good for hip abduction, knee flexion, ankle dorsiflexion and plantarflexion (rhoc >or= 0.7) but poor for hip adduction (rhoc = 0.5). Reproducibility for all PROMs was verified. Resident's VE showed high reliability (rhoc >or= 0.8) for hip flexion and popliteal angle. Good correlation was found for hip rotations and knee flexion (rhoc >or= 0.7). Poor results were obtained for ankle PROMs (rhoc < 0.6) as well as hip adduction and abduction, the results of which not being reproducible. Influence of experience was clearly demonstrated for PROMs of hip rotations, adduction and abduction as well as ankle plantarflexion. CONCLUSION: Accuracy of VE of passive hip flexion and knee PROMs is high regardless of the examiner's experience. Same accuracy can be found for hip rotations and abduction whenever VE is performed by an experienced examiner. Goniometric evaluation is recommended for passive hip adduction and for ankle PROMs.

Reverse shoulder arthroplasty: does reduced medialisation improve radiological and clinical results?

The purpose of this retrospective study was to assess the effect of the reduced medialisation of the Arrow reverse shoulder prosthesis on short-term clinical and radiological results. The clinical and radiological results of 47 Delta III reverse prostheses and 49 Arrow reverse prostheses were retrospectively compared at a minimum of twelve months follow-up. There was a significant increase (p < 1.10(-4)) in range of motion from the preoperative range in the two groups except for internal rotation in the Delta III group (p = 0.1). Radiological analysis on anteroposterior view in neutral position showed greater lateralisation (p < 0.001) with the Arrow prosthesis. Scapular notching was noted in 32 patients with a Delta III prosthesis, and in no instance with an Arrow prosthesis. Complication rates were 14.9% for the Delta group and 10.2% for the Arrow group. The design features of the Arrow prosthesis--reduced medialisation of the center of rotation with lateralisation of the humerus--were found to be associated with slight improvement in range of motion and absence of scapular notching.

Osteomyelitis of the rib due to Streptococcus pneumoniae: a very rare condition in children.

Rib osteomyelitis is a rare disease. We present a previously unreported case of Streptococcus pneumoniae osteomyelitis of the rib. A 4-month-old-infant presented with fever, irritability and abdominal tenderness. Pericostal collection was discovered incidentally on ultrasound; it was first drained by needle aspiration and appropriate antibiotic therapy was given, with resolution of fever in 24 h, but recurrence of symptoms 4 days later, with swelling over the affected rib. Surgical drainage with resection of the infected portion of the rib were done followed by a prolonged course of intravenous and then oral antibiotics, without any recurrence at 6 months follow-up. A review of the pertinent literature was made. This case demonstrates that the spectrum of pathogens potentially responsible for rib osteomyelitis may be broader than previously reported. The management and outcome are similar to rib osteomyelitis due to any other bacteria.