Treatment of Radial Head Fractures and Need for Revision Procedures at 1 and 2 Years.

PURPOSE: Optimal treatment strategies for radial head fractures remain a subject of debate. We examined national practice patterns in the management of radial head fractures to determine rates of surgical treatment, type of surgery employed, and the incidence of reoperation. METHODS: Between 2007 and 2011, we identified patients with radial head fractures along with their associated injuries by International Classification of Diseases, Ninth Revision codes in a national database of orthopedic insurance records. For those who underwent surgery, the type of intervention was identified and each patient was observed to determine whether a subsequent procedure was needed by 1 and 2 years. Chi-square analysis was performed to make comparisons between groups. RESULTS: A total of 58,404 radial head fractures were identified between 2007 and 2011; of these, 2,981 underwent surgical treatment (5.1%). Rates of surgical intervention were significantly higher in the context of associated injuries. Among the 2,981 radial head fractures treated surgically, 57.1% underwent open reduction internal fixation (ORIF), 37.9% were treated with radial head arthroplasty, and 4.9% underwent radial head excision. When the surgically treated radial head fracture was associated with a coronoid fracture, elbow dislocation, or proximal ulna fracture, 64.2%, 54.3%, and 47.2% were treated with arthroplasty, respectively, compared with 32.6%, 41.9%, and 52.6% treated with ORIF, respectively. After initial surgical treatment, 12.7% and 14.4% of radial head fractures that underwent ORIF required a secondary surgery at 1 and 2 years, respectively, compared with 8.6% and 10.7% of radial head arthroplasties and 8.3% and 8.4% of resections. CONCLUSIONS: Rates of arthroplasty were significantly higher in the context of associated injury, particularly in the setting of a coronoid fracture or elbow dislocation. Fractures initially treated with ORIF had a higher rate of revision surgery at both 1 and 2 years after the index procedure compared with arthroplasty. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic II.

Demographic analysis of open and arthroscopic distal clavicle excision in a private insurance database.

PURPOSE: The purpose of this study was to evaluate and quantify the demographic characteristics of patients undergoing open and arthroscopic distal clavicle excision (DCE) in the United States while also describing changes in practice patterns over time. METHODS: Patients who underwent DCE from 2004 to 2009 were identified by Current Procedural Terminology (CPT) codes in a national database of orthopaedic insurance records. The year of procedure, age, sex, geographic region, and concomitant rotator cuff repair or subacromial decompression (SAD) were recorded for each patient. Results were reported as the incidence of procedures identified per 10,000 patients searched in the database. RESULTS: Between 2004 and 2009, 73,231 DCEs were performed; 74% were arthroscopic and 26% were open. The incidence of arthroscopic DCE increased from 37.8 in 2004 to 58.5 in 2009 (P < .001), whereas the incidence of open DCE decreased from 21.1 in 2004 to 14.1 in 2009 (P < .001). Sixty-one percent of DCEs were performed in men (P < .001). Women were more likely to undergo an arthroscopic procedure (P < .001). Arthroscopic DCE was most common in patients aged 50 to 59 years (P < .001). Open DCE was most common in patients aged 60 to 69 years (P < .001). Open rotator cuff repair and SAD were concomitantly performed in 38% and 23% of open DCEs, respectively. Arthroscopic rotator cuff repair and SAD were concomitantly performed in 33% and 95% arthroscopic DCEs, respectively. CONCLUSIONS: This analysis of DCE using a private insurance database shows that arthroscopic DCEs progressively increased, whereas open DCEs concomitantly decreased between 2004 and 2009. The majority of DCEs were performed in men between the ages of 50 and 59 years. Both arthroscopic and open DCEs are frequently performed in conjunction with rotator cuff repair or SAD. LEVEL OF EVIDENCE: Level IV, cross-sectional study.

Kinematic analysis of diseased and adjacent segments in degenerative lumbar spondylolisthesis.

BACKGROUND CONTEXT: Degenerative spondylolisthesis is a common pathologic condition that leads to lumbar instability and significant clinical symptoms. The effect of this pathology on adjacent lumbar motion segments, however, has not yet been studied. PURPOSE: To characterize the motion characteristics of lumbar degenerative spondylolisthesis at both the diseased and adjacent levels in patients with low-grade, single-level lumbar degenerative spondylolisthesis using kinetic magnetic resonance imaging (kMRI). STUDY DESIGN: Retrospective study of patient kMRIs. PATIENT SAMPLE: One-hundred twelve patient MRIs with low-grade, single-level lumbar spondylolisthesis were included. OUTCOME MEASURES: Angular and translational motion. METHODS: This study compared 112 patients diagnosed with low-grade (Grade 1 or 2), single-level lumbar degenerative spondylolisthesis at L3-L4, L4-L5, or L5-S1 with 296 control patients without spondylolisthesis. Angular and translational motion were measured using patient kMRIs. The level of slip was graded according to the Meyerding classification system, and disc degeneration was classified according to the Pfirrmann system. Instability was defined as translational motion greater than 4 mm. RESULTS: Lumbar hypomobility was often present regardless of the level of degenerative spondylolisthesis. A slip at L3-L4 resulted in the largest decrease in lumbar range of motion. Instability at the diseased level was most common at L3-L4 (36%), followed by L5-S1 (31%) and L4-L5 (30%). Instability at the adjacent segments was most frequent at L4-L5 (49%), followed by L5-S1 (34%) and L3-L4 (23%). Patients with stable spondylolisthesis generally had decreased angular motion at all lumbar levels. Translational motion at the diseased level was consistently increased. Disc degeneration was significantly greater at the level of slip for the L3-L4 and L4-L5 spondylolisthesis groups and equal to the control group in the L5-S1 group. There was no significant difference in disc degeneration at adjacent segments in L3-L4 and L4-L5 degenerative spondylolisthesis patients, but there was a significant decrease with an L5-S1 slip. CONCLUSIONS: There were a similar percentage of patients in each degenerative spondylolisthesis group with lumbar instability. Angular motion decreased at the diseased level with L3-L4 and L5-S1 spondylolisthesis, but increased with L4-L5 spondylolisthesis. Translational motion, however, increased at the diseased level in all three groups. There was compensatory hypermobility at adjacent levels in patients with unstable spondylolisthesis at L3-L4 and L4-L5, but not at L5-S1.

Lumbar clinical adjacent segment pathology: predilection for proximal levels.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To evaluate reoperations for lumbar adjacent segment pathology (ASP) during a 10-year period. SUMMARY OF BACKGROUND DATA: ASP after lumbar arthrodesis is an important clinical problem. There remains controversy, however, on the distribution of the most commonly affected levels. METHODS: Thirty-one patients undergoing revision operation for ASP in the lumbar spine were included in this study. Patients' charts were evaluated for demographic data including age at index and revision operations, time to revision operation, and index and revision levels fused. RESULTS: L4-L5 was the most commonly instrumented level in both single-level (n = 12), and multilevel (n = 13) index fusions. The mean length of time from the index operation to revision surgery was 81 months (range, 11-570 mo). Kaplan-Meier analysis predicted a disease-free survival rate of 32.3% at 5 years and of 12.9% at 10 years after the index operation. L3-L4 was the most commonly affected level by ASP with 75% (16/20) requiring reoperation. L2-L3 was the next most commonly affected level at 52% (14/27). The L5-S1 disk was relatively protected from ASP, with only 4/17 (24%) disks at risk developing ASP. A subgroup analysis of patients undergoing revision after a single-level L4-L5 arthrodesis revealed ASP at L3-L4 in 83% (10/12) of patients, compared with only 3/12 (25%) at L5-S1 (P < 0.05). Of all cases of ASP, the proximal segments were involved 90% of the time. CONCLUSION: ASP most commonly affects proximal levels in the lumbar spine. In this cohort of patients undergoing revision fusion for ASP, 90% of affected levels were rostral to the index level(s). In patients undergoing L4-L5 single-level arthrodesis, L3-L4 is at high risk, whereas L5-S1 is somewhat protected. Surgeons should pay particular attention to proximal levels when planning a lumbar arthrodesis, however, motion segments distal to fusion may not be as protected as previously thought. LEVEL OF EVIDENCE: 4.

Inhibition of RhoA signaling with increased Bves in trabecular meshwork cells.

PURPOSE: Blood vessel epicardial substance (Bves) is a novel adhesion molecule that regulates tight junction (TJ) formation. TJs also modulate RhoA signaling, which has been implicated in outflow regulation. Given that Bves has been reported in multiple ocular tissues, the authors hypothesize that Bves plays a role in the regulation of RhoA signaling in trabecular meshwork (TM) cells. METHODS: Human TM cell lines NTM-5 and NTM-5 transfected to overexpress Bves (NTM-w) were evaluated for TJ formation, and levels of occludin, cingulin, and ZO-1 protein were compared. Assays of TJ function were carried out using diffusion of sodium fluorescein and transcellular electrical resistance (TER). Levels of activated RhoA were measured using FRET probes, and phosphorylation of myosin light chain (MLC-p), a downstream target of RhoA, was assessed by Western blot analysis. RESULTS: Overexpression of Bves led to increased TJ formation in NTM-5 cells. Increased TJ formation was confirmed by increased occludin, cingulin, and ZO-1 protein. Functionally, NTM-w cells showed decreased permeability and increased TER compared with NTM-5 cells, consistent with increased TJ formation. NTM-w cells also exhibited decreased levels of active RhoA and lower levels of MLC-p than did NTM-5 cells. These findings support a TJ role in RhoA signaling. CONCLUSIONS: Increased Bves in TM cells leads to increased TJ formation with decreased RhoA activation and decreased MLC-p. This is the first report of a regulatory pathway upstream of RhoA in TM cells. In TM tissue, RhoA has been implicated in outflow regulation; thus, Bves may be a key regulatory molecule in aqueous outflow.