Senior Thesis Day
Massachusetts General Hospital – Bigelow Amphitheatre
Friday, June 18, 2010

Senior Resident Thesis Presentations

Osgood Lecture  •  First Session  •  Second Session  •  Third Session  •  Fourth Session
James N. Weinstein, MD

First Session
Moderator:   Thomas S. Thornhill, MD

Thesis Presenter: Seth Jerabek, MD
Topic:  The Validity of Using Administrative Claims Data in Total Joint
Arthroplasty Outcomes Research
Advisor:   Harry E. Rubash, MD
Discussant:   Henrik Malchau, MD

Dr. Jerabek investigated the concordance between administrative and clinical diagnosis and procedure codes for revision total joint arthroplasty (TJA). Data was collected from 764 consecutive revision TJA procedures from 4 hospitals. For revision total hip arthroplasty, concordance between clinical diagnoses and administrative claims was very good for dislocation, mechanical loosening, and periprosthetic joint infection but considerably lower for prosthetic implant failure breakage and other mechanical complication. Similarly, for revision total knee arthroplasty diagnoses, concordance was very good for periprosthetic fracture, periprosthetic joint infection, mechanical loosening, and osteolysis, but much lower for implant failure/breakage and other mechanical complication. Concordance for TJAspecific procedure codes was very good only for revision total knee arthroplasty patellar component revisions and tibial insert exchange procedures. Total (all-component) revisions were overcoded for hips and undercoded for knees. Dr. Jerabek concluded that improved clinical documentation and continued education are needed to enhance the value of these codes.

Dr. Malchau congratulated Dr. Jerabek on an excellent study, but he raised the question of bias. Specifically, he asked if administrative personnel would be tempted to upcode in order to get a higher DRG for the hospital which may make the ICD-9 codes less valid. Dr. Weinstein felt that the most accurate data would come directly from the surgeon, rather than using administrative coding data, but he agreed that poor surgeon reporting rates would be difficult to overcome.

Thesis Presenter:   Brian M. Haus, MD
Topic:  Evolution of the Insertion Site of the Anterior Cruciate Ligament after
Suture Repair Enhanced with a Collagen Platelet Composite
Advisor:   Martha M. Murray, MD
Discussant:   Mininder Kocher, MD

Dr. Haus investigated the healing process of the ACL at its insertion site. He hypothesized that that there would be histologic changes in the insertion site morphology after transection and repair of the ACL with a collagen-platelet composite, and that these changes would be age-dependent. Skeletally immature (open physes), adolescent (closing physes) and adult (closed physes) Yucatan mini-pigs underwent ACL transection and suture repair using a collagen-platelet composite. The response to repair of the insertion site was evaluated histologically at 1, 2, 4 and 15 weeks. He found the following changes in young and adolescent animals, including (1) loss and return of collagen alignment in the fibrous zone; (2) osteoclastic resorption of the tidemark and fibrocartilage zones at 2 and 4 weeks; and (3) partial reappearance of tidemark and fibrocartilage layers at 15 weeks. In adult animals, however, degenerative changes were noted at 15 weeks and included (1) loss of the parallel arrangement of collagen fibers in the fibrous zone and (2); disorganization and loss of columnation of the chondrocytes in the fibrocartilage zone. Dr. Haus concluded that his findings suggest that histologic changes do occur during healing of the ACL and that the magnitude of these changes may be a function of skeletal maturity.

Dr. Kocher discussed Dr. Haus’ study on age-related changes in the ACL. He posed the question as to whether or not the transection model is clinically relevant and lauded Dr. Haus’ for his contribution on trends on PRP with ACL reconstruction going from the bench to the bedside. Dr. Weinstein posed the question of specific gene therapy in future trends with ACL reconstruction.

Thesis Presenter:   Darren Lebl, MD
Topic:   Vertebral Artery Injury Secondary to Cervical Spine Trauma: A Multicenter Study and Proposed Screening Guidelines
Advisor:   Mitchel B Harris, MD
Discussant:   George Velmahos, MD

Dr. Lebl investigated the relatively unknown predictors, screening, and management of vertebral artery injury (VAI) in cervical spine fractures or dislocations. In his study, data was prospectively collected from the American College of Surgeons (ACS) trauma registries at three level 1 trauma centers. Inclusion criteria required the presence of a positive cervical spine computed tomography (CT) scan and a CT angiogram (CTA) as a screening study for a VAI. Fracture pattern, patient information, contraindications to treatment of VAI, in-hospital stroke rate, and mortality rate were determined. A total of 1,205 patients with cervical spine fractures or injuries were identified. VAI in association with a cervical spine injury was diagnosed in 42 patients (a 3.5% incidence). Statistically significant independent predictors of VAI included fracture displacement into the transverse foramen > 1mm, basilar skull fracture, occipital-cervical dissociation, and seronegative spondyloarthropathy (AS or DISH). A minimum of one contraindication to anti-platelet or anti-coagulation treatment for VAI was present in 100 patients (39.5%) that were screened by CT angiography. Thirty out of the 42 patients (71%) diagnosed with a VAI did not receive any new medication or treatment subsequent to the identification of the injury during their hospitalization. The stroke rate for VAI was 6 out of 42 patients (14%) and the stroke related mortality rate was 2 of out 42 patients (4.8%). Dr. Lebl proposed a screening algorithm that identified patients who are candidates for treatment and are at higher risk to minimize institutional cost and radiation exposure.

Dr. Velmahos congratulated Dr. Lebl on a remarkable study which pulled together data from MGH, BWH and BI in a collaborative effort as well as his use of in-depth statistical analysis. He agreed with Dr. Lebl,s conclusion on the factors related to the risk of VAI but noted the difficulty in developing screening guidelines for a complex, potentially life threatening injury. He raised the basic fundamental questions such as the value of one life. In addition, he raised the issue of screening liberally by a rather safe test and discussed the predictive value of CTA versus more invasive diagnostic studies such as catheter angiography. Dr. Weinstein congratulated him on the use of a multi-center collaborative study to develop guidelines to empirically treat a difficult problem.

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