Faculty Bibliography

PURPOSE: A 2-part biomechanical study was constructed to test the hypothesis that coronal morphology of the thumb metacarpophalangeal joint impacts the assessment of instability in the context of radial collateral ligament (RCL) injury. METHODS: Fourteen cadaveric thumbs were disarticulated at the carpometacarpal joint. Four observers measured the radius of curvature of the metacarpal (MC) heads. In a custom jig, a micrometer was used to measure the RCL length as each thumb was put through a flexion and/or extension arc under a 200 g ulnar deviation load. Strain was calculated at maximal hyperextension, 0 degrees , 15 degrees , 30 degrees , 45 degrees , and maximal flexion. Radial instability was measured with a goniometer under 45 N stress. The RCL was then divided and measurements were repeated. Analysis of variance and Pearson correlation metrics were used. RESULTS: The RCL strain notably increased from 0 degrees to 30 degrees and 45 degrees of flexion. With an intact RCL, the radial deviation was 15 degrees at 0 degrees of flexion, 18 degrees at 15 degrees , 17 degrees at 30 degrees , 16 degrees at 45 degrees , and 14 degrees at maximal flexion. With a divided RCL, instability was greatest at 30 degrees of flexion with 31 degrees of deviation. The mean radius of curvature of the MC head was 19 +/- 4 mm. Radial instability was inversely correlated with the radius of curvature to a considerable degree only in divided RCL specimens, and only at 0 degrees and 15 degrees of flexion. CONCLUSIONS: The RCL contributes most to the radial stability of the joint at flexion positions greater than 30 degrees . The results suggest that flatter MC heads contribute to stability when the RCL is ruptured and the joint is tested at 0 degrees to 15 degrees of metacarpophalangeal flexion. CLINICAL RELEVANCE: The thumb MC joint should be examined for RCL instability in at least 30 degrees of flexion.

INTRODUCTION: As with some procedures, trauma fellowship training and greater surgeon experience may result in better outcomes following intramedullary nailing (IMN) of diaphyseal femur fractures. However, surgeons with such training and experience may not always be available to all patients. The purpose of this study is to determine whether trauma training affects the post-operative difference in femoral version (DFV) following IMN. MATERIALS AND METHODS: Between 2000 and 2009, 417 consecutive patients with diaphyseal femur fractures (AO/OTA 32A-C) were treated via IMN. Inclusion criteria for this study included complete baseline and demographic documentation as well as pre-operative films for fracture classification and post-operative CT scanogram (per institutional protocol) for version and length measurement of both the nailed and uninjured femurs. Exclusion criteria included bilateral injuries, multiple ipsilateral lower extremity fractures, previous injury, and previous deformity. Of the initial 417 subjects, 355 patients met our inclusion criteria. Other data included in our analysis were age, sex, injury mechanism, open vs. closed fracture, daytime vs. nighttime surgery, mechanism of injury, and AO and Winquist classifications. Post-operative femoral version of both lower extremities was measured on CT scanogram by an orthopaedic trauma fellowship trained surgeon. Standard univariate and multivariate analyses were performed to determine statistically significant risk factors for malrotation between the two cohorts. RESULTS: Overall, 80.3% (288/355) of all fractures were fixed by trauma-trained surgeons. The mean post-operative DFV was 8.7 degrees in these patients, compared to 10.7 degrees in those treated by surgeons of other subspecialties. This difference was not statistically significant when accounting for other factors in a multivariate model (p>0.05). The same statistical trend was true when analyzing outcomes of only the more severe Winquist type III and IV fractures. Additionally, surgeon experience was not significantly predictive of post-operative version for either trauma or non-trauma surgeons (p>0.05 for both). CONCLUSIONS: Post-operative version or percentage of DFV >15 degrees did not significantly differ following IMN of diaphyseal femur fractures between surgeons with and without trauma fellowship training. However, prospective data that removes the inherent bias that the more complex cases are left for the traumatologists are required before a definitive comparison is made.

BACKGROUND: Evolution of periarticular implant technology has led to stiffer, more stable fixation constructs. However, as plate options increase, comparisons between different sized constructs have not been performed. The purpose of this study is to biomechanically assess any significant differences between 3.5- and 4.5-mm locked tibial plateau plates in a simple bicondylar fracture model. MATERIALS AND METHODS: A total of 24 synthetic composite bone models (12 Schatzker V and 12 Schatzker VI) specimens were tested. In each group, six specimens were fixed with a 3.5-mm locked proximal tibia plate and six specimens were fixed with a 4.5-mm locking plate. Testing measures included axial ramp loading to 500 N, cyclic loading to 10,000 cycles and axial load to failure. RESULTS: In the Schatzker V comparison model, there were no significant differences in inferior displacement or plastic deformation after 10, 100, 1,000 and 10,000 cycles. In regards to axial load, the 4.5-mm plate exhibited a significantly higher load to failure (P = 0.05). In the Schatzker VI comparison model, there were significant differences in inferior displacement or elastic deformation after 10, 100, 1,000, and 10,000 cycles. In regards to axial load, the 4.5-mm plate again exhibited a higher load to failure, but this was not statistically significant (P = 0.21). CONCLUSIONS: In the advent of technological advancement, periarticular locking plate technology has offered an invaluable option in treating bicondylar tibial plateau fractures. Comparing the biomechanical properties of 3.5- and 4.5-mm locking plates yielded no significant differences in cyclic loading, even in regards to elastic and plastic deformation. Not surprisingly, the 4.5-mm plate was more robust in axial load to failure, but only in the Schatzker V model. In our testing construct, overall, without significant differences, the smaller, lower-profile 3.5-mm plate seems to be a biomechanically sound option in the reconstruction of bicondylar plateau fractures.

Insufficiency fractures present a significant problem in patients with osteoporosis. We report a case of bilateral iliac wing insufficiency fracture following low energy injury in an 87-year-old osteoporotic woman occurring 2 weeks after primary total hip arthroplasty. There are only a few reports of insufficiency fractures involving the ilium in the literature, and diagnosis has proven challenging, as radiographs are often negative at symptom onset. Magnetic resonance or radionuclide imaging is generally necessary for definitive diagnosis. This case highlights the importance of careful perioperative management of patients with osteoporosis.

Fixation of fragility fractures with plates and screws often results in loss of fixation and need for revision surgery. Locking plates and screw were introduced to improve fixation of fragility fractures and have been in use for a decade. This review was conducted to compile evidence that locking plates and screws improve fixation of fragility fractures. A search of PubMed was performed to identify biomechanical studies as well as clinical series of fragility fractures treated with locking plates. Biomechanics papers had to use models of osteoporotic bone and had to directly compare locking plates with traditional plates. Clinical studies included case series in which locking plates were applied to elderly patients with fractures of the proximal humerus and periprosthetic distal femur fractures. Most studies are retrospective case series. Locking plates lead to greater stability and higher loads to failure than traditional plates. When applied to proximal humerus fractures, uncomplicated healing occurs in 85% of patients. Constant and Dash scores approach normal values. For distal femoral periprosthetic fractures, union rates of 75% are reported with a malunion rate of 10%. Early evidence suggests that locking plates improve results of treatment of proximal humerus fractures and distal femoral periprosthetic fractures in the elderly. Loss of fixation is associated with failure to achieve stability at the fracture site. Principles of fracture fixation in osteoporotic bone defined prior to the introduction of locking plates should still be applied.

Clinical pathways reduce length of stay which is critical for hospitals to remain financially sound. We sought to determine if a multimodal pathway focusing on pre-op discharge planning and pre-emptive pain and nausea management lead to reduced length of stay, better pain management, and more rapid functional gains without an increase in post-op complications. A multimodal pathway incorporating pre-op discharge planning and pre-emptive pain and nausea management was initiated in August of 2007. Physical therapy began the day of surgery. Two hundred eleven patients treated over a 3-month period with the new pathway were compared to 192 patients treated in the last 3 months of an older pathway. Length of stay, VAS scores for pain, and the incidence of nausea were compared. Length of time to achieve functional milestones while in hospital and the incidence of complications out to 6 months were compared. Average length of stay was reduced by 0.26 days. VAS scores for pain were lower. Several functional milestones were achieved earlier and complications were not increased. Efforts to control nausea were not successful and severe nausea was experienced in 40% of patients in both groups. This enhanced pathway can lead to an important reduction in length of stay. Although this reduction seems small, it can significantly increase patient throughput and increase hospital capacity. Post-op nausea continues to be an impediment in patient care after TKR.