Introduction

There is a high prevalence of obesity in the United States and the numbers are increasing. These patients comprise a significant portion of the shoulder arthroplasty patient population. There are several reports of outcomes in the literature on obese patients after total knee or hip replacement, however, this data is lacking in the shoulder arthroplasty patient population. The purpose of this study is to compare the functional outcomes and complications of obese patients undergoing shoulder arthroplasty with the non-obese population.

Introduction

While shoulder elevation can be reliably restored following reverse total shoulder arthroplasty (RTSA), patients may experience a loss of internal and external rotation. Several recent studies have investigated scapular notching and have made suggestions regarding glenosphere placement in order to minimize its occurrence. However, very few studies have looked at how changes in glenosphere placement in RTSA affect internal and external rotation. The purpose of this study was to determine the effect of glenosphere position on internal and external rotation range of motion at various degrees of scaption following RTSA. We hypothesized that alteration in glenosphere position will affect the amount of impingement-free internal and external rotation.

Thirty-five patients were followed prospectively from their referral to the Problem Fracture Service with chronic osteomyelitis of diaphyseal bone between November 1994 and June 1999.

The patients were treated using a closed double-lumen suction irrigation system following reaming and arthroscopic debridement of the intramedullary canal; this is a modified system based on the work of Charles Lautenbach. Results of these procedures were regularly followed up in clinic, and between June and July 2007 the whole cohort was reviewed via postal questionnaire, telephone and case note review.

At a mean follow up of 101 months, 26 were living with no evidence of recurrence, 4 had died of unrelated causes with no evidence of recurrent infection. Four patients had persisting problems with sinus discharge requiring intermittent antibiotic therapy and 1 patient had his limb amputated for recurrent metaplastic change.

These results gave this cohort an 86% clearance of infection, with recurrence in 12%, which is comparable to the Papineau and Belfast techniques with significantly less surgical insult to the patient.

Introduction: etiology of late infection after arthroplasty can be difficult to establish. Histology is the gold standard for infection in patients without inflammatory arthritis but diagnosis in inflammatory arthritis depends on culture (Atkins et al). Real-time PCR offers a rapid and direct assessment for staphylococci and enterococci infection but has not been widely assessed.

The aims of this study were

to develop the Roche lightcycler Staphylococcal and Enterococcal PCR kits to facilitate diagnosis of hip and knee prosthetic infections

Methods: uplicate, multiple tissue samples were taken (with separate sterile instruments) at the 1^st stage of revision after informed consent. One set were cultured and results interpreted by the Oxford criteria. The second set were extracted using the Qiagen DNA kit, purified (in-house method) and tested using the Roche lightcycler kits.

Results:53 patients undergoing 2 stage revision for suspected infection were recruited.15 (28.3%) had negative histology and no inflammatory arthritis; 3 with single positive cultures and negative PCR – considered contaminants.

29 patients had non-inflammatory arthritis. 14/18 (77.8%) with positive cultures had staphylococci +/or enterococci isolated and 10 PCR results correlated. The other 11 patients had negative cultures.

9 patients had inflammatory arthritis. Six were culture negative and of the other three, 2 were positive for staphylococci on culture with 1 positive by PCR.

Discussion: Negative staphylococcal PCR correlates with the isolation of staphylococci from only one sample. This agrees with the Oxford criteria that such samples may be considered contaminants. Additional positives detected by staphylococcal PCR alone are rare.

Enterococcal PCR confirmed culture positivity in 2/3 patients. An additional 5 positive PCR’s were obtained from patients’ culture negative for enterococci. It is not clear if these are false positives or more sensitive detection of enterococcal isolation.

Background. Just under 2% of the joint infection work performed over the last 10 years in our institution has involved organisms found in the oropharynx. The issue of antibiotic prophylaxis for dental work in the presence of a joint prosthesis is controversial. However, advanced dental sepsis requires detection and treatment prior to joint replacement.

Methods. Patients from whom non B-haemolytic streptococcal were recovered from revisions of prosthetic joints over the period 1993–2003 were retrospectively reviewed for predisposing factors.

Results. 9 patients had viridans streptococcal infection detected and confirmed by histology and culture at excision arthroplasty. There were 5 total hip joints, 3 knee arthroplasties and 1 shoulder affected. No patient had a history of endocarditis. Two of the patients had previously had multiple revisions. Mean interval in these patients since last surgery was 7.6 years. All patients underwent 2 stage revision procedures. All patients required multiple dental extractions in the interval between 1st and 2nd stage surgery.

On reviewing the patients’ histories further: One patient had reported a broken tooth reported at the time of surgery and been given reassurancethat it was safe to proceed. One patient had an overt dental abscess ongoing for 15 years and one patient had an occult dental abscess revealed on radiology. Two other patients had extensive dental caries with blackened stumps as teeth. Follow-up after antibiotic treatment and revision arthroplasty is limited in these cases but results appear satisfactory at up to five years.

Conclusion. Poor dental care is associated with an increased risk of arthroplasty infection. Looking in the mouth should be a routine part of pre-op assessment prior to primary joint replacement, just as it would be in a cardiac surgery unit. Patients referred from other centres for revision arthroplasty should receive a dental examination if excision arthroplasty cultures yield viridans streptococci.

Bone loss of the glenoid may preclude performing a glenoid replacement. In this setting a hemiarthroplasty will be the best option available. While the debate of hemiarthroplasty versus total shoulder replacement (TSR) continues, most would prefer to replace the glenoid if there is gross loss of articular cartilage and the cuff is intact or repairable. In order to ensure a lasting glenoid component adequate bone stock is critical. Neer noted in 463 TSR’s that the glenoid was able to be inserted in all but 2 patients. Bone grafting was necessary in 20 patients. Hill and Norris reported on 17 patients with bone grafting for glenoid replacement and found that only 53% of their patients had satisfactory results and 29% had revisions – often early.

In order to evaluate the adequacy of the glenoid satisfactorily, true AP and axillary views are important. Version angles can be difficult to evaluate on a standard axillary view, if rotated – so a CT scan will be useful. Defects may be central (cavitary) or segmental. Posterior lesions are common in osteoarthritis and central lesions in rheumatoid arthritis or after failure of a prior glenoid.

Management will be determined by the degree of bone loss. In glenoid central defects, bone grafting with morselised bone with possibly a fascial graft will fill the defect and present future options. Segmental or asymmetrical defects are managed either by asymmetrical reaming or bone grafting at the site combined with glenoid insertion. If gross loss of bone is present posteriorly the bone can be reamed and the humeral head inserted with decreased retroversion. If the glenoid has asymmetrical wear then reaming to a smooth glenoid will improve the results of a hemiarthroplasty as noted by Bigliani.

Humeral bone loss such as a removed tuberosity will create problems for cuff reattachment that may require allografts.

In reconstructing the humerus, restoration of length is critical to avoid inferior instability. This may require a custom prosthesis and an attempt to restore bone stock.

Shoulder instability following shoulder arthroplasty may be classified as posterior, anterior, superior or inferior. The basic causes include, malposition of the components, incorrect version of the glenoid or humeral cuts, soft tissue contractures or laxity, and cuff deficiency. These may be present and isolated as combined deficiencies.

As always, avoidance is best, but it is the most common complication of shoulder arthroplasty and this must be dealt with correctly. Recognition of the anatomic aetiology is critical. The proper evaluation with x-ray, CT and MRI will be critical to either avoid the problem or treat it correctly. Normally the glenoid is nearly perpendicular to the scapular while the humeral version is about 30° retroverted.

After defining the anatomic problem, proper component positioning, elimination of contractures, plication of capsular laxity and cuff repair or, replacement, will ensure the best opportunity for a stable shoulder.

Cartilage deficiency has increasingly been a consideration for non-arthroplasty approaches – particularly for smaller, limited defects.

Initially, simple debridement was advocated by Pridie and subsequently by the late John Insall, with modest results and rarely regeneration of a joint space. Subsequently, articular grafting with plugs was suggested by Mueller and later on, Hangody. Mosaicplasty has been used by many for smaller defects of 1–2 cm and by a few with multiple grafts for large defects. Problems concern the source and the technique itself, since it is difficult to achieve a smooth configuration.

Presently, I utilise micro fracture for small < 2 cm defects in active patients. If there is bone loss then a mosaic is considered. Larger defects are managed with cell cultured chrondrocytes. If the bone loss is significant an allograft may be utilised. Micro fracture, if the postoperative protocol is carefully followed, appears to help ~75% of patients. All cellular techniques as described by Lars Peteson claim 80–85% success in the short term. Our own results are more in the 50% range. Younger, active patients with defects of 2 x 2 or larger may be candidates for ACI treatment. Our average defect size is ~460 mm2. Our major problem has consisted of periosteum over-growth in about 25% of our patients. Using thin periosteum and good surgical technique may decrease this problem.