While the diagnosis of obvious shoulder infection is easy: the patient has local and systemic signs of inflammation, abnormal joint fluid and serum lab tests, and positive cultures for indisputable pathogens.  On the other hand, the diagnosis of a stealth shoulder infection is complicated: the most frequently implicated bacteria (Cutibacterium) is a commensal organism commonly isolated from normal skin, normal deep tissues and healthy shoulder joints. In a stealth infection the usual clinical evidence of infection is absent. A pragmatic definition of bacterial infection is "bac ..read more

The authors of Tendon stump type on magnetic resonance imaging is a predictive factor for retear after arthroscopic rotator cuff repair investigated the tear size, Goutallier stage, and global fatty degeneration index, seeking factors associated with retear after cuff repair. They also classified the rotator cuff tendon stump (yellow circle) by preoperative oblique coronal image plane T2-weighted fat-suppressed magnetic resonance imaging (MRI), comparing its signal intensity to that of the nearby deltoid muscle (red circle) in 305 patients having arthros ..read more

Randomization enables unbiased estimation of treatment effects; randomization attempts to assure that treatment-groups are balanced with respect to the important covariates. Unfortunately for us shoulder surgeons, surgical treatments are rarely assigned randomly. Propensity matching is an attempt to use observational data to compare two treatment groups by accounting for the covariates that are associated with the outcome.  The possibility of bias arises because a difference in the outcome between treatment groups may be caused by factors that predict which treatment the patie ..read more

 A 55 year old active man with limiting pain and stiffness of the left shoulder presented with these x-rays. Wishing to avoid the risks and limitations associated with the plastic glenoid component used in conventional total shoulder arthroplasty, he elected to proceed with a ream and run procedure. At followup 17 years after his procedure, he demonstrated excellent comfortable range of motion.  X-rays showed stable fixation of the impaction autografted humeral component along with healing of the reamed glenoid without evidence of glenoid wear and no humeral osteolysis ..read more

The concept of overstuffing in shoulder arthroplasty was introduced over 30 years ago (Practical Evaluation and Management of the Shoulder p181-184): "in many conditions requiring shoulder arthroplasty, the capsule and ligaments are contracted and therefore excessively limit the range of motion. Shoulder arthroplasty tends to further tighten the capsule because the degenerated humeral head is replaced by a larger one, and because a glenoid component is added to the surface of the glenoid bone, consuming more space than the degenerated cartilage it replaces. Thus, the components "stuff" t ..read more

Shoulder arthroplasty provides a great opportunity for patients with arthritis to recover lost shoulder comfort and function. However, recovery from the operation may challenge the patients' mental as well as their physical toughness. There is evidence that resilience may be an important attribute in the recovery from shoulder surgery. Several scales have been validated for assessing a person's resilience, including the Brief Resilence Scale and the The Connor-Davidson Resilience Scale, which assesses the ability to adapt to change, to deal with whatever comes, to see the&nb ..read more

The use of pyrocarbon as a bearing surface for shoulder hemiarthroplasty has attracted interest because of the theoretical advantages of increased smoothness and boundary lubrication. Some of the recent literature has been summarized in a recent post: Pyrocarbon shoulder hemiarthroplasty - what do we think we know? In vitro comparison of wear characteristics of PyroCarbon and metal on bone: Shoulder hemiarthroplasty examined the wear of cow femoral cortical bone when tested with pyrocarbon and cobalt chromium alloy hemiarthroplasty humeral heads in a wear simulator. How re ..read more

 The humeral component in reverse total shoulder is exposed to bending, torsional and inferiorly displacing loads. The component can be stabilized with cement or with a tight fitting humeral component.  The former creates a stress riser at the distal tip and complicates potential revision The latter can lead to the risk of fracture on insertion and stress shielding (yellow arrows).  These undesirable features can be avoided through the use of a thinner humeral stem secured into place with impaction autograft (or allograft if autograft is not available). By filling the spac ..read more

One of the most common modes of baseplate failure in reverse total shoulder (RSA) is rocking horse loosening resulting from the inability of the fixation to resist upward directed force applied by the humerus.   As pointed out in Factors affecting fixation of the glenoid component of a reverse total shoulder prothesis, the ability of the baseplate to resist the rocking (green arrow) from superiorly directed loading (black arrow) depends in large part on (1) compression of the upper aspect of the baseplate against bone of good quality (yellow arrow) and (2) the pullout resistan ..read more

 Long term outcomes in shoulder surgery are a challenge for some key reasons: (1) the longer the minimum followup duration for the study, the greater the percentage of patients who will be lost to followup (because they have moved, no longer wish to provide followup, are grappling with other illnesses, are getting care elsewhere, or have passed away). So over time the final followup cohort becomes progressively less representative of the initial group of patients having the procedure.  (2) long term radiographic followup is even harder to get in high percentage because of the logisti ..read more