What Factors are Predictive of Patient-reported Outcomes? A Prospective Study of 337 Shoulder Arthroplasties.

BACKGROUND: Although shoulder arthroplasties generally are effective in improving patients' comfort and function, the results are variable for reasons that are not well understood. QUESTIONS/PURPOSES: We posed two questions: (1) What factors are associated with better 2-year outcomes after shoulder arthroplasty? (2) What are the sensitivities, specificities, and positive and negative predictive values of a multivariate predictive model for better outcome? METHODS: Three hundred thirty-nine patients having a shoulder arthroplasty (hemiarthroplasty, arthroplasty for cuff tear arthropathy, ream and run arthroplasty, total shoulder or reverse total shoulder arthroplasty) between August 24, 2010 and December 31, 2012 consented to participate in this prospective study. Two patients were excluded because they were missing baseline variables. Forty-three patients were missing 2-year data. Univariate and multivariate analyses determined the relationship of baseline patient, shoulder, and surgical characteristics to a "better" outcome, defined as an improvement of at least 30% of the maximal possible improvement in the Simple Shoulder Test. The results were used to develop a predictive model, the accuracy of which was tested using a 10-fold cross-validation. RESULTS: After controlling for potentially relevant confounding variables, the multivariate analysis showed that the factors significantly associated with better outcomes were American Society of Anesthesiologists Class I (odds ratio [OR], 1.94; 95% CI, 1.03-3.65; p = 0.041), shoulder problem not related to work (OR, 5.36; 95% CI, 2.15-13.37; p < 0.001), lower baseline Simple Shoulder Test score (OR, 1.32; 95% CI, 1.23-1.42; p < 0.001), no prior shoulder surgery (OR, 1.79; 95% CI, 1.18-2.70; p = 0.006), humeral head not superiorly displaced on the AP radiograph (OR, 2.14; 95% CI, 1.15-4.02; p = 0.017), and glenoid type other than A1 (OR, 4.47; 95% CI, 2.24-8.94; p < 0.001). Neither preoperative glenoid version nor posterior decentering of the humeral head on the glenoid were associated with the outcomes. The model predictive of a better result was driven mainly by the six factors listed above. The area under the receiver operating characteristic curve generated from the cross-validated enhanced predictive model was 0.79 (generally values of 0.7 to 0.8 are considered fair and values of 0.8 to 0.9 are considered good). The false-positive fraction and the true-positive fraction depended on the cutoff probability selected (ie, the selected probability above which the prediction would be classified as a better outcome). A cutoff probability of 0.68 yielded the best performance of the model with cross-validation predictions of better outcomes for 236 patients (80%) and worse outcomes for 58 patients (20%); sensitivity of 91% (95% CI, 88%-95%); specificity of 65% (95% CI, 53%-77%); positive predictive value of 92% (95% CI, 88%-95%); and negative predictive value of 64% (95% CI, 51%-76%). CONCLUSIONS: We found six easy-to-determine preoperative patient and shoulder factors that were significantly associated with better outcomes of shoulder arthroplasty. A model based on these characteristics had good predictive properties for identifying patients likely to have a better outcome from shoulder arthroplasty. Future research could refine this model with larger patient populations from multiple practices. LEVEL OF EVIDENCE: Level II, therapeutic study.

Impaction autografting: bone-preserving, secure fixation of a standard humeral component.

BACKGROUND: When fixed with bone ingrowth, a tight diaphyseal press fit, or cement, the humeral component of a shoulder arthroplasty may present problems of malposition, stress shielding, or periprosthetic fracture or difficulty with removal at revision arthroplasty. We have avoided the need for these fixation methods by using impaction cancellous autografting of the humeral stem, minimizing contact between the prosthetic stem and the humeral cortex. This study presents the radiographic survivorship of impaction-autografted humeral implants using component subsidence as the primary endpoint. METHODS: We reviewed 286 primary anatomic shoulder arthroplasties having an average follow-up of 4.9 ± 2.7 years. Initial postoperative radiographs and minimum 2-year follow-up radiographs were evaluated by 3 observers to assess subsidence. RESULTS: Two different implants (Humeral Replacement Prosthesis [HRP] and Global Advantage prosthesis) were used. Of 286 stems, 267 (93.4%) had not subsided. The Global Advantage prosthesis had a subsidence-free survival rate of 98.5% at 5 years. The stiffer-stemmed HRP used early during the study had a higher rate of subsidence compared with the currently used Global Advantage stem (hazard ratio, 5.6; P = .001). Radiolucent lines of 2 mm or greater were less common for the Global Advantage prosthesis than for the HRP in each of 7 zones (P < .001). Total shoulder arthroplasty was associated with a higher rate of subsidence compared with hemiarthroplasty (hazard ratio, 2.6; P = .12). CONCLUSIONS: Impaction autografting provides a secure, durable, bone-preserving means of humeral component fixation in anatomic shoulder arthroplasty.

Management of intraoperative posterior decentering in shoulder arthroplasty using anteriorly eccentric humeral head components.

BACKGROUND: Posterior humeral decentering presents a challenge in glenohumeral arthroplasty. Soft tissue releases and osteophyte resection can lead to intraoperative decentering not evident preoperatively. Inferior outcomes result if decentering is not addressed as a part of the arthroplasty. When there is >50% posterior subluxation of the humeral head on passive elevation of the arm at surgery, we have used an anteriorly eccentric humeral head component to improve centering of the humeral articular surface on the glenoid. METHODS: We reviewed the 2-year outcomes for 33 shoulder arthroplasties in which anteriorly eccentric humeral heads were used to manage posterior decentering identified at surgery. Rotator interval plication was performed in 16 cases as an adjunctive stabilizing procedure. Shoulders were evaluated preoperatively and postoperatively with the Simple Shoulder Test (SST). Radiographic centering was characterized before surgery and at follow-up on standardized axillary radiographs with the arm held in a position of functional elevation. RESULTS: With the anteriorly eccentric head component, preoperative radiographic humeral decentering was reduced from 10.4% ± 7.9% to 0.9% ± 2.3% postoperatively (P < .001). SST scores improved from 4.8 ± 2.3 to 10.0 ± 2.3 (P < .001). Preoperative posterior humeral head decentering did not correlate with preoperative glenoid version. Glenoid retroversion was 19.8° ± 8.9° preoperatively and 15.5° ± 7.5° postoperatively. CONCLUSIONS: Posterior decentering identified at surgery when standard trial components are in place can be addressed by replacing the anatomic humeral head with an anteriorly eccentric humeral head component.

Loose glenoid components in revision shoulder arthroplasty: is there an association with positive cultures?

BACKGROUND: Glenoid loosening is one of the most common causes of total shoulder failure. High rates of positive cultures of Propionibacterium and coagulase-negative staphylococcus have been found among shoulders having surgical revision for glenoid loosening. This study reviewed the culture results in a series of surgical revisions for failed total shoulder arthroplasty to determine the relationship between glenoid loosening and positive cultures. METHODS: The medical records of 221 patients without obvious evidence of infection who underwent revision total shoulder arthroplasty were reviewed to examine the association between the security of fixation of the glenoid component and the results of cultures obtained at revision surgery. RESULTS: Of the revised shoulders, 53% had positive cultures; 153 of the shoulders (69%) had a loose glenoid component, whereas 68 (31%) had secure glenoid component fixation. Of the 153 loose glenoid components, 82 (54%) had at least 1 positive culture and 44 (29%) had 2 or more positive cultures of the same microorganism. Similarly, of the 68 secure glenoid components, 35 (51%) had at least 1 positive culture (P = .77) and 14 (21%) had 2 or more positive cultures of the same microorganism (P = .25). Explanted glenoid components that were loose had a higher rate of culture positivity (56% [24/43]) in comparison to explanted glenoid components that were well fixed (13% [1/8]) (P = .05). CONCLUSION: Propionibacterium and coagulase-negative staphylococcus are commonly recovered in revision shoulder arthroplasty, whether or not the glenoid components are loose.

Detritic synovitis can mimic a Propionibacterium periprosthetic infection.

PURPOSE: The purpose of this article is to illustrate that the clinical findings of detritic synovitis complicating a total shoulder arthroplasty can strongly resemble those of a 'stealth' periprosthetic shoulder infection with a low-virulence organism such as Propionibacterium. METHODS: We present a review of the literature and illustrate an example of detritic synovitis following a total shoulder arthroplasty. RESULTS: The combination of glenoid component loosening and humeral osteolysis after total shoulder arthroplasty are commonly attributed to periprosthetic infection with low virulence organisms, such as Propionibacterium or coagulase negative Staphylococcus. Such a periprosthetic infection can appear long after the index joint replacement. This article points out that these same findings may occur with a non-infectious process initiated by polyethylene, cement or metal debris-detritic synovitis. CONCLUSIONS: At present, the important differentiation between these two etiologies can only be ascertained by awaiting the results of cultures obtained at the time of revision surgery.

Magnetic resonance rotator cuff fat fraction and its relationship with tendon tear severity and subject characteristics.

BACKGROUND: Compared with the Goutallier classification, chemical shift-based magnetic resonance (MR) fat quantification has superior reliability and accuracy in evaluation of muscle fatty infiltration. We used this method to assess the relationship between rotator cuff (RC) muscle fat fractions, tendon disease severity, and subject characteristics. METHODS: In total, 182 subjects with shoulder symptoms underwent shoulder MR imaging including additional sequences for fat quantitation. Then, fat fraction maps were manually segmented, and custom software was used to compute the fat fraction. Goutallier scores were also obtained. The relationship between fat fraction and tendon tear severity and subject characteristics was assessed with descriptive statistics, analysis of variance, Student t test of different subgroups, and simple and multiple linear regression analysis. RESULTS: Statistically higher supraspinatus fat fractions were observed in subgroups with tendon tears >3 cm, retraction >1 cm, age >50 years, body mass index (BMI) >30, higher Goutallier score, female gender, and longer symptom duration. A significant linear relationship was seen between RC fat fraction and tendon disease severity, age, and BMI but not symptom duration. Multiple regression models with fat fraction and tendon disease, age, BMI, and gender were significant for all 4 muscles (P < .001). The slope of fatty infiltration increase with age was reduced after adjustment for tendon disease, BMI, and gender. CONCLUSION: RC fat fraction assessed by chemical shift MR demonstrated a significant linear relationship with tendon tear severity, age, BMI, and gender but not with symptom duration.

Post-traumatic ulnar artery thrombosis: outcome of arterial reconstruction using reverse interpositional vein grafting at 2 years minimum follow-up.

PURPOSE: Treatment of posttraumatic symptomatic ulnar artery thrombosis (UAT) is controversial. This study reports the outcome at 2 years minimum follow-up of a uniform approach using reversed interpositional vein grafting to treat symptomatic patients with UAT. METHODS: The records of all patients with vascular disease of the upper extremity who were revascularized at the authors' institution were retrospectively reviewed, and the following inclusion criteria were applied: (1) arteriographically proven UAT treated with excision of the involved segment and reversed interpositional vein grafting; (2) absence of collagen vascular disease, coagulopathy, or peripheral vascular disease, (3) minimum follow-up of 24 months. Twelve patients (13 hands) were identified and evaluated before surgery and at final follow-up using the following health-related quality of life outcome instruments: (1) McCabe cold sensitivity severity scale, (2) McGill visual analog pain scale, (3) Levine symptom and function scale, and (4) Wake Forest University symptom scale (pain, numbness, and cold intolerance). Digital microvascular perfusion testing (laser Doppler perfusion imaging and isolated cold stress testing) was also performed, and the final test was compared with 28 normal controls. All patients were evaluated for graft patency as determined by Allen's testing and/or Doppler ultrasound. RESULTS: Ten of the 13 grafts were patent at final follow-up (77% patency rate). In all the patients with patent grafts, the Levine symptom scale, the McGill visual analog pain scale, the McCabe cold sensitivity severity scale, and the isolated cold stress testing responses of the patients were significantly improved at final follow-up. Isolated cold stress testing responses were not different from those of normal controls. The changes in the Levine function scale, Wake Forest University scale, and laser Doppler perfusion imaging were not significant. In the nonpatent grafts (3 of 13), 2 patients still complained of pain, numbness, and cold sensitivity, whereas 1 patient has minimal symptoms and continues to improve. CONCLUSIONS: Successful arterial reconstruction in symptomatic posttraumatic UAT decreases symptoms, improves function and microvascular physiology, and has a positive effect on the health-related quality of life. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Arthroscopic management of volar lunate facet fractures of the distal radius.

The clinical outcome of an intraarticular distal radius fracture is generally thought to be associated with the following factors: amount of radial deformity, joint congruity, and associated soft-tissue injuries. The proposed technique to manage this fracture pattern that involves a displaced volar lunate facet fragment uses wrist arthroscopy and pinning. Distraction of the fracture before arthroscopy is accomplished either by external fixation or by the arthroscopy tower. A freer elevator is introduced dorsally to disimpact the fragments, and next, a nerve hook is used to reduce the volar lunate facet, which is subsequently pinned to the radial styloid. The remaining fragments are reduced with interfragmentary pin fixation, and this anatomical articular construct is fixed to the radial metaphysis. The advantages of this technique are: (a) accurate assessment of articular congruency by direct visualization, (b) identification and repair of associated lesions, and (c) minimal soft tissue disruption. Potential disadvantages of external fixation supplemented by interfragmentary pins may be that it does not provide for rigid stable fixation, and therefore, does not allow for early motion compared to open reduction and internal fixation. Furthermore, it is technically challenging, and is therefore suggested as an alternative for the aforementioned fracture pattern.

Specific phospholipid oxidation products inhibit ligand activation of toll-like receptors 4 and 2.

OBJECTIVE: We have previously shown that phospholipid oxidation products of 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (ox-PAPC) inhibit lipopolysaccharide (LPS)-induced E-selectin expression and neutrophil binding in human aortic endothelial cells (HAECs). The current studies identify specific phospholipids that inhibit chemokine induction by Toll-like receptor-4 (TLR4) and -2 (TLR2) ligands inECs and macrophages. METHODS AND RESULTS: Measurements of interleukin (IL)-8 and monocyte chemotactic protein-1 levels secreted from ox-PAPC- and LPS-cotreated ECs indicate that ox-PAPC inhibits activation of TLR4 by LPS. The effects of IL-1beta and tumor necrosis factor-alpha, which utilize the same intracellular signaling molecules, were not inhibited. Cell fractionation and immunofluorescence analyses demonstrate that LPS induces membrane translocation of the LPS receptor complex to a lipid raft/caveolar fraction in ECs. Ox-PAPC inhibits this translocation and alters caveolin-1 distribution. Supporting an important role for caveolae in LPS action, overexpression of caveolin-1 enhanced LPS-induced IL-8 synthesis. Ox-PAPC also inhibits the effect of TLR2 and TLR4 ligands in human macrophages. CONCLUSIONS: These studies report a novel mechanism that involves alterations to lipid raft/caveolar processing, by which specific phospholipid oxidation products inhibit activation by TLR4 and TLR2 ligands. These studies have broader implications for the role of ox-PAPC as a regulator of specific lipid raft/caveolar function.