Complications of operative fixation of proximal humeral fractures in patients with rheumatoid arthritis

Risk factors for nonunion following open reduction and internal fixation for proximal humerus fractures

PURPOSE

The incidence of proximal humerus fractures (PHF) is rising and surgical intervention carries risk for fracture nonunion. The purpose was (1) to compare patient demographics of those that developed nonunion and (2) identify patient risk factors that predispose to nonunion following open reduction and internal fixation (ORIF) for PHF.

METHODS

A retrospective review of the Medicare Claims Database from 2005 to 2014 for patients who underwent primary ORIF for PHFs. Patients who developed nonunion were identified as the study group (n = 1020) and compared to a control group (n = 51,209). Primary endpoints were to compare demographics of the study group and the comparison cohorts and to identify patient-related risk factors associated with nonunion within 6-months following the index procedure. A logistic regression model was constructed to determine the association of comorbid conditions on developing a nonunion. A p value of 0.001 was the significance threshold.

RESULTS

Patients who developed nonunion were younger, more likely to be male, and had higher Elixhauser-Comorbidity Index scores (7 vs. 5; p < 0.0001) when compared with controls. Iron deficiency anemia (OR: 1.32; p = 0.0001), tobacco use (OR: 1.32; p = 0.0004), rheumatoid arthritis (OR: 1.29; p = 0.0001), depression (OR: 1.28; p = 0.0002), and BMI range from 30-39 kg/m² (OR: 1.21; p = 0.001) were significant risk factors for nonunion.

CONCLUSIONS

Certain patient risk factors including tobacco use, iron deficiency anemia, rheumatoid arthritis, depression, and a BMI in the range of 30-39 were associated with nonunion within 6 months of ORIF for PHF. This study may help in the risk stratification of these patients.

Glenohumeral arthritis as a risk factor for proximal humerus nonunion

BACKGROUND

Proximal humerus fractures are common injuries and nonsurgical treatment has proven to yield good to excellent clinical results. A small percentage of these fractures go on to delayed or nonunion and the incidence and risk factors for this complication are poorly understood. We hypothesize that adjacent joint stiffness of the glenohumeral joint might lead to an increased rate of nonunion for proximal humerus fractures.

METHODS

A search of the entire Medicare database from 2005 to 2011 was performed to identify 38,754 patients who sustained a proximal humerus fracture including 13,802 with co-existing ipsilateral shoulder osteoarthritis (OA) and 24,952 with co-existing diagnosis of rheumatoid arthritis (RA). A cohort of 301,987 patients served as a control. Medical co-morbidities and fracture complications were compared between the cohorts.

RESULTS

The incidence of delayed union at 3 and 6 months for OA and RA groups were significantly increased compared to control at 0.79% and 1.74%, and 0.67% and 1.86%, respectively (p < 0.001). Nonunion rates were also significantly increased (p < 0.001) in the OA and RA cohorts at 9 months and 1 year with incidences of 2.39%, 2.89% and 2.59% and 3.08%, Respectively. The incidence of nonunion in the control cohort at the same time points was 1.13% and 1.35%.

CONCLUSIONS

The coexistence of shoulder OA or a diagnosis of RA nearly doubled in the incidence of proximal humerus nonunion. This is the first study investigating this association in the shoulder and should be considered along with traditional nonunion risk factors in the treatment algorithm.

Joint chondrolysis

Although the disease was first described in the hip, reports of chondrolysis in nearly all diarthrodial joints have since emerged with considerable variations in the literature.Despite speculation among clinicians and researchers about the implicit causal pathways and etiologic contributors associated with chondrolysis, definitive answers remain elusive.The term chondrolysis has been applied to varied levels of joint cartilage destruction from focal chondral defects to diffuse cartilage loss, revealing a lack of consistency in the application of diagnostic criteria to guide differential disease classification.Differentiating between the various potential etiologies associated with chondrolysis provides opportunities for the prevention of the disease.

Management of proximal humeral nonunions and malunions

Surgical treatment of proximal humeral nonunions and malunions are technically challenging. Osteosynthesis with bone grafting for the treatment of nonunions is indicated in young, active patients with adequate bone stock in the proximal fragment and preservation of the glenohumeral articular surfaces. Corrective osteotomy may be a reasonable option for proximal humeral malunions in young patients without evidence of degenerative joint disease. Arthroplasty for proximal humerus nonunions and malunions has a guarded outcome because of limitations in shoulder motion, but pain relief is more consistently improved upon.