Purpose: Orthopaedic residency training requires intellectual and motor skill development. In this study we aim to develop a model to evaluate junior resident proficiency and efficiency versus senior residents in the placement of a center-center guidewire during fixation of an intertrochanteric proximal femur fracture utilizing a computer-based haptic simulator. We hypothesize the junior residents will utilize more fluoroscopy and require more time to complete the task.

Method: Post-graduate year residents (PGY) 3–5s, labeled Group II, placed a single central guide pin into a femoral head utilizing a surgical simulator four times. PGY 1–2s, labeled Group I, completed the same task six times. The residents were then evaluated based on final tip-apex distance (TAD), fluoroscopy time, time to complete the task, total number of distinct attempts at pin placement for each femur construct as well as final three-dimensional location of the pin from the isometric center of the femoral head. This project was approved by the institutional IRB.

Conclusion: In this study we displayed that based on our simulator model there was no statistical difference between Group I and II in time to completion, final placement on AP view, and tip-apex distance. There was a statistically significant difference in the anterior/posterior placement of the wire between the two groups, fluoroscopy time, and number of attempts per trial. Our findings suggest a computer based surgical simulator can identify measurable differences in surgical proficiency between junior and senior orthopaedic residents.

Purpose: Metal-on-Metal (MOM) hip resurfacing is a popular alternative to conventional hip arthroplasty. The purpose of the present study is to compare patient characteristics and radiographic findings for revision versus non-revision cases treated at a single center with a MOM resurfacing device.

Method: Eighty-nine MOM resurfacing arthroplasties were performed between December 2001 and June 2006. Subjects were assessed for implant revision status, age, gender, weight, operative side, primary diagnosis, femoral head size, and time to revision. Postoperative radiographs were assessed for acetabular cup inclination and femoral stem inclination relative to the femoral neck.

Results: Thirteen of 89 hips (14.6%) have required revision to date with follow-up ranging from 4 (a revision) to 91 months. Female gender, smaller implant size, and a diagnosis of osteonecrosis were all associated with lower device survival. A significant difference in acetabular cup angle was observed between revised and non-revised hips. However, this difference can largely be attributed to two outliers in cup position associated with early migration and the difference became non-significant when these outliers were excluded. No significant difference was found in stem angle between revised and non-revised hips. The revision rate for the first 25 hips was 24% versus 8% for the next 64 hips. Females accounted for 56% of subjects 1–25 and 23% of subjects 26–89. Seven of the 8 failures for the first 25 procedures occurred beyond 4 years follow-up. Only 2 early device failures (< 2 yrs) were identified and both were in the 26–89 subgroup.

Conclusion: Despite representing only 33% of included subjects, females accounted for 62% of revision procedures. An apparent learning curve was identified by a lower device survival proportion for the first 25 hips versus hips 26–89. However, this learning curve was not associated with failures which could be attributed to acetabular or femoral component malpositioning and is likely explained by the higher proportion of females enrolled early in the study. Taken together, we propose the apparent “learning curve” exhibited in our study is not wholly technical in nature but rather influenced by changes in patient selection over time by the operative surgeon.

Purpose: The current study examines the impact of the 80-hour work week on the number of surgical cases performed by PGY2 – PGY5 Orthopedic residents. We also evaluated Orthopaedic In-training Exam (OITE) scores during the same time period.

Method: Data were collected from the ACGME national database for 3 academic years prior to and 5 years after July 1, 2003. CPT surgical procedure codes logged by all residents three years prior to and five years following implementation of the 80-hour work week were compared. The average raw OITE scores for each class obtained during the same time period were also evaluated. Data were reported as the mean ± standard deviation (SD) and group means were compared using independent t-tests.

Results: No statistical difference was noted in the number of surgical procedure codes logged prior to or after institution of the 80-hour week during any single year of training. However, an increase in the number of CPT codes logged in the PGY-3 year after 2003 did approach significance (457.7 vs. 551.9, p=0.057). There was a statistically significant increase in total number of cases performed (464.4 vs. 515.5 p=0.048). No statistically significant difference was noted in the raw OITE scores before or after work hour restrictions for our residents or nationally.

Conclusion: We found no statistical difference for each residency class in the average number of cases performed or OITE scores. We also found no statistical difference in the national OITE scores. Our data suggest that the impact of the 80 hour work has not had a detrimental effect in these two resident training measurements.

Purpose: Metal-on-metal (MOM) bearing surfaces release ions locally and into the systemic circulation. This elevation raises concern about the long term effects of elevated metal ions. The goal of the present study was to monitor serum cobalt (Co) and chromium (Cr) levels in patients after MOM resurfacing hip arthroplasty with the Cormet 2000 prosthesis. We present here pilot data on Co and Cr levels in patients with bilateral versus unilateral hip resurfacing devices.

Method: We prospectively collected patient characteristics, outcome, and serum samples from device implanted subjects at 6 months, 1, 2, and 3 years following surgery. Unilateral patients had one implant during the entire course of follow-up and bilateral patients were included after the second implant surgery was performed. Serum Co/Cr levels were determined using high-resolution inductively coupled plasma mass spectrometry. Students t-test was used to compare ion levels in two groups based on the number of resurfacing implants (bilateral versus unilateral).

Results: 41 unilateral and 9 bilateral subjects were enrolled and followed for serum Co and Cr levels. In general, Co/Cr levels were increased at all time points when compared to control levels in both groups. Bilateral subjects had average serum levels concentrations significantly higher than those observed for unilateral cases (Co: 5.99 vs 2.56 μg/L (p=0.0001); Cr: 6.66 vs 3.60 (p=0.0009).

Conclusion: Elevated serum Co/Cr levels were observed at all time points following implantation in both groups and serum levels were nearly 2 times higher in the bilateral group. Based on these preliminary findings, patients undergoing bilateral total hip resurfacing arthroplasty may need to be monitored more closely than those patients receiving unilateral devices. In addition, these bilateral cases may be at a greater risk of ion level toxicities than the unilateral population.

Purpose: The purpose of this study was to monitor serum cobalt (Co) and chromium (Cr) levels in patients after metal-on-metal resurfacing hip arthroplasty with the Cormet 2000® prosthesis, and to evaluate the effect of patient characteristics, prosthesis characteristics, clinical and radiographic measures on metal levels.

Methods: Serum Co and Cr levels were determined in 32 patients with Cormet resurfacing prostheses at 0.5, 1 and 2 years postoperatively using ICP-MS and are reported as & #61549;g/L. Control levels were measured in 20 patients without implants.

Results: Medium Co and Cr were 0.21 and 0.16 in controls without implants. Medium Co at 6 months (2.65), 1 year (3.62) and 2 years (2.80), and Cr at 6 months (3.74), 1 year (4.73) and 2 years (4.68) were signifi-cantly increased in the Cormet group when compared to control levels (p < .0001). Metal levels did not correlate with cup inclination, component position, head size, age, weight, sex or Harris Hip scores. Markedly elevated Co (35, 63) and Cr (13, 70) levels were found in two patients with excessive cup abduction. In addition, one patient with a loose implant that required revision had markedly elevated Co (19) and Cr (44) levels.

Conclusions: Significantly increased levels of cobalt and chromium were released from Cormet 2000 articulations at all time points. Excessive cup abduction was associated with markedly elevated ion levels indicating that accurate cup placement is an important consideration in resurfacing arthroplasty. The significantly increased trace metal levels following resurfacing with the Cormet prosthesis is a concern and warrants further monitoring.

Purpose: The purpose of our study was to compare serum titanium levels in patients with the three-piece modular AcuMatch® and one-piece nonmodular Versys® titanium femoral components.

Methods: Blood samples were obtained at multiple time points for four years after the surgery in patients with the Versys® one-piece (47 patients) or AcuMatch® three-piece (70 patients) femoral stems. Control levels were measured in 20 patients without titanium implants. Titanium (Ti) levels were measured using high resolution inductively coupled-plasma mass spectroscopy by a technician blinded to the patient groups.

Results: Medium Ti was significantly lower in the control group (.21 & #61549;g/L), when compared to patients with one- and three-part stems at all follow-up periods (p < .02). At 1 and 2 years post-operatively, medium Ti levels in the three-part group (3.1 and 3.4 & #61549;g/L) were significantly higher than levels in the one-part group (1.7 and 1.6 & #61549;g/L) (p < .004). At 3 and 4 years, medium titanium levels were not significantly different in the one-part group (2.5 and 2.7 & #61549;g/L) when compared to the three-part group (3.5 and 3.1 & #61549;g/L) (p > .05).

Conclusions: The intraoperative flexibility provided by modular femoral stems may be offset by increased wear at modular junctions. Ti levels were significantly higher in patients with a highly modular three-part femoral stems at 1 and 2 years but no significant difference was found at 3 and 4 years postoperatively. Continued monitoring of these patients is warranted to determine if metal levels can be used to evaluate stem performance.