Intraarticular Matrix Metalloproteinases and Aggrecan Degradation Are Elevated After Articular Fracture.

BACKGROUND: Posttraumatic osteoarthritis (OA) is a variant of OA that can develop after articular injury. Although the mechanism(s) of posttraumatic OA are uncertain, the presence and impact of postinjury proteolytic enzymes on articular cartilage remain unknown. To our knowledge, there are no studies that evaluate the presence of matrix metalloproteinases (MMPs) or aggrecan degradation after articular fracture. QUESTIONS/PURPOSES: (1) Are MMP concentrations and aggrecan degradation elevated after intraarticular fracture? (2) Are MMP concentrations and aggrecan degradation greater in high-energy injuries compared with low-energy injuries? (3) Do the concentrations of these biomarkers remain elevated at a secondary aspiration? METHODS: Between December 2011 and June 2013, we prospectively enrolled patients older than 18 years of age with acute tibial plateau fracture. Exclusion criteria included age older than 60 years, preexisting knee OA, injury greater than 24 hours before evaluation, contralateral knee injury, history of autoimmune disease, open fracture, and non-English-speaking patients. During the enrollment period, we enrolled 45 of the 91 (49%) tibial plateau fractures treated at our facility. Knee synovial fluid aspirations were obtained from both the injured and uninjured knees; two patients received aspirations in the emergency department and the remaining patients received aspirations in the operating room. Twenty patients who underwent spanning external fixator followed by definitive fixation were aspirated during both surgical procedures. MMP-1, -2, -3, -7, -9, -10, -12, and -13 concentrations were quantified using multiplex assays. Aggrecan degradation was quantified using sandwich enzyme-linked immunosorbent assay. RESULTS: There were higher concentrations of MMP-1 (3.89 ng/mL [95% confidence interval {CI}, 2.37-6.37] versus 0.37 ng/mL [95% CI, 0.23-0.61], p < 0.001), MMP-3 (457.35 ng/mL [95% CI, 274.5-762.01] versus 129.17 ng/mL [95% CI, 77.01-216.66], p < 0.001), MMP-9 (6.52 ng/mL [95% CI, 3.86-11.03] versus 0.96 ng/mL [95% CI, 0.56-1.64], p < 0.001), MMP-10 (0.52 ng/mL [95% CI, 0.40-0.69] versus 0.23 ng/mL [95% CI, 0.17-0.30], p < 0.001), and MMP-12 (0.18 ng/mL [95% CI, 0.14-0.23] versus 0.10 ng/mL [95% CI, 0.0.081-0.14], p = 0.005) in injured knees compared with uninjured knees. There was not a detectable difference in MMP concentrations or aggrecan degradation between high- and low-energy injuries. MMP-1 (53.25 versus 3.89 ng/mL, p < 0.001), MMP-2 (76.04 versus 0.37 ng/mL, p < 0.001), MMP-3 (1250.62 versus 457.35 ng/mL, p = 0.002), MMP-12 (1.37 versus 0.18, p < 0.001), MMP-13 (0.98 versus 0.032 ng/mL, p < 0.001), and aggrecan degradation (0.58 versus 0.053, p < 0.001) were increased at the second procedure (mean, 9.5 days; range, 3-21 days) as compared with the initial procedure. CONCLUSIONS: Because MMPs and aggrecan degradation are elevated after articular fracture, future studies are necessary to evaluate the impact of elevated MMPs and aggrecan degradation on human articular cartilage. CLINICAL RELEVANCE: If further clinical followup can demonstrate a relationship between posttraumatic OA and elevated MMPs and aggrecan degradation, they may provide potential for therapeutic targets to prevent or delay the destruction of the joint. Additionally, these markers may offer prognostic information for patients.

Functional Outcomes After Arthroscopic Scapulothoracic Bursectomy and Partial Superomedial Angle Scapulectomy.

BACKGROUND: Arthroscopic scapulothoracic bursectomy with partial superomedial angle scapulectomy has been described as a treatment for persistent scapulothoracic bursitis with varying results. PURPOSE: To evaluate patients after arthroscopic scapulothoracic bursectomy utilizing validated functional outcome instruments. STUDY DESIGN: Case series. METHODS: Fifteen patients underwent arthroscopic scapulothoracic bursectomy and partial superomedial angle scapulectomy. Thirteen patients were available for review at a mean 27-month follow-up (range, 13-65 months). Patients were evaluated preoperatively with a history, physical examination evaluating medial scapula border tenderness and crepitus, pain visual analog scale (VAS) score, and the simple shoulder test (SST). Postoperatively, patients were evaluated with all preoperative questionnaires as well as a satisfaction survey and the American Shoulder and Elbow Surgeons (ASES) score. RESULTS: SST scores improved significantly from a mean 7.7 ± 3.1 preoperatively to 10.3 ± 2.3 postoperatively (P = .03). VAS pain scores reduced significantly from 6.5 ± 2.2 preoperatively to 2.3 ± 2.4 postoperatively (P < .001). Ninety-two percent (12/13) of patients were satisfied, and 92% (12/13) stated they would have the surgical procedure performed again. The mean ASES postoperative score was 80.1 (range, 38-100). The 2 clinical failures (ASES scores <50) had either a workers' compensation claim with persistent medial border tenderness or ongoing rotator cuff disease. Despite lower ASES scores, these patients were still satisfied with the procedure and would undergo it again. CONCLUSION: Arthroscopic scapulothoracic bursectomy with partial superomedial angle scapulectomy provides significant improvements in pain and functional outcomes. Even in patients at risk for poorer clinical outcomes, patient satisfaction and willingness to undergo the surgical procedure again was still high.