Faculty Bibliography

Osteogenesis imperfecta is a heritable group of collagen-related disorders that affects up to 50,000 people in the United States. Although the disease is most symptomatic in childhood, adults with osteogenesis imperfecta also are affected by the sequelae of the disease. Orthopaedic manifestations include posttraumatic and accelerated degenerative joint disease, kyphoscoliosis, and spondylolisthesis. Other manifestations of abnormal collagen include brittle dentition, hearing loss, cardiac valve abnormalities, and basilar invagination. In general, nonsurgical treatment is preferred for management of acute fractures. High rates of malunion, nonunion, and subsequent deformity have been reported with both closed and open treatment. When surgery is necessary, surgeons should opt for load-sharing intramedullary devices that span the entire length of the bone; locking plates and excessively rigid fixation generally should be avoided. Arthroplasty may be considered for active patients, but the procedure frequently is associated with complications in this patient population. Underlying deformities, such as malunion, bowing, rotational malalignment, coxa vara, and acetabular protrusio, pose specific surgical challenges and underscore the importance of preoperative planning.

BACKGROUND:In human TKA studies, intraosseous regional administration (IORA) of prophylactic antibiotics achieves local tissue antibiotic concentrations 10 times greater than systemic administration. However, it is unclear if such high concentrations provide more effective prophylaxis. QUESTIONS/PURPOSES/OBJECTIVE:We asked: (1) What prophylaxis dosage and route (intravenous [IV] versus IORA of prophylactic antibiotics) produce less in vivo bacterial burden compared with no-antibiotic controls? (2) Compared with controls, what prophylaxis dosage and route yield fewer colony-forming units (CFUs) in euthanized animals in a model of TKA? (3) Is prophylactic IORA of antibiotics more effective than same-dose IV antibiotic administration in reducing CFUs? METHODS:Mice (six to nine per group) were block randomized to one of six prophylaxis regimens: control, systemic cefazolin (C100IV), IORA of cefazolin (C100IORA), systemic vancomycin (V110IV), low-dose systemic vancomycin (V25IV), and low-dose IORA of vancomycin (V25IORA). Surgery involved placement of an intraarticular knee prosthesis, followed by an inoculum of bioluminescent Staphylococcus aureus strain Xen36. Biophotonic imaging assessed in vivo bacterial loads, and after 4 days bacterial load was quantified using culture-based techniques. Comparisons were made for each prophylactic regimen to controls and between same-dose IV and IORA of prophylactic antibiotic regimens. RESULTS:Mice treated with systemic high-dose vancomycin, IORA of vancomycin, or IORA of cefazolin had lower in vivo Staphylococcus aureus burdens (median area under curve, Control: 5.0 × 10(6); V110IV: 1.5 × 10(6), difference of medians 3.5 × 10(6), p = 0.003; V25IV: 1.94 × 10(6), difference 3.07 × 10(6), p = 0.49; V25IORA: 1.51 × 10(6), difference 3.5 × 10(6), p = 0.0011; C100IORA: 1.55 × 10(6), difference 3.46 × 10(6), p = 0.0016; C100IV: 2.35 × 10(6), difference 2.66 × 10(6), p = 0.23.) Similar findings were seen with culture-based techniques on recovered implants. IORA of prophylactic antibiotics was more effective than same-dose IV administration in reducing bacterial load on recovered implants (median CFUs < 7.0 × 10(0) vs 2.83 × 10(2), p = 0.0183). CONCLUSIONS:IORA of prophylactic cefazolin and vancomycin was more effective than the same dose of antibiotic given systemically. The effectiveness of vancomycin in particular was enhanced by IORA of prophylactic antibiotics despite using a lower dose. CLINICAL RELEVANCE/CONCLUSIONS:Our study supports previous studies of IORA of prophylactic antibiotics in humans and suggests this novel form of administration has the potential to enhance the effectiveness of prophylaxis in TKA. Because of concerns regarding antibiotic stewardship, IORA of prophylactic vancomycin may be more appropriately restricted to patients having TKA who are at greater risk of infection, and clinical trials are in progress.

STUDY DESIGN/METHODS:Experimental animal study of convective transport in the intervertebral disc. OBJECTIVE:To quantify the effects of mechanical loading rate on net transport into the healthy and degenerative intervertebral disc in vivo. SUMMARY OF BACKGROUND DATA/BACKGROUND:Intervertebral disc degeneration is linked with a reduction in transport to the avascular disc. Enhancing disc nutrition is, therefore, a potential strategy to slow or reverse the degenerative cascade. Convection induced by mechanical loading is a potential mechanism to augment diffusion of small molecules into the disc. METHODS:Skeletally mature New Zealand white rabbits with healthy discs and discs degenerated via needle puncture were subjected to low rate axial compression and distraction loading for 2.5, 5, 10, 15, or 20 minutes after a bolus administration of gadodiamide. Additional animals with healthy discs were subjected to high-rate loading for 10 minutes or no loading for 10 minutes. Transport into the disc for each loading regimen was quantified using post-contrast-enhanced magnetic resonance imaging. RESULTS:Low-rate loading resulted in the rapid uptake and clearance of gadodiamide in the disc. Low-rate loading increased net transport into the nucleus by a mean 16.8% and 12.6% in healthy and degenerative discs, respectively. The kinetics of small molecule uptake and clearance were accelerated in both healthy and degenerative discs with low-rate loading. In contrast, high-rate loading reduced transport into nucleus by a mean 16.8%. CONCLUSION/CONCLUSIONS:These results illustrate that trans-endplate diffusion can be enhanced by forced convection in both healthy and degenerative discs in vivo. Mechanical loading-induced convection could offer therapeutic benefit for degenerated discs by enhancing uptake of nutrients and clearance of by-products. LEVEL OF EVIDENCE/METHODS:4.

OBJECTIVE:Golf is a widely popular sport in the United States with 29 million Americans participating in the game. With an aging population and increased incidence of glenohumeral degenerative arthritis, the number of active golfers requiring total shoulder replacement is on the rise. This study aims to evaluate the effect of total shoulder replacement on golfing activity. DESIGN/METHODS:Retrospective; questionnaire. SETTING/METHODS:Survey. PARTICIPANTS/METHODS:Three hundred sixty-seven patients were identified based on Current Procedural Terminology codes who underwent total shoulder arthroplasty (TSA) between January 2004 and January 2013. INTERVENTIONS/METHODS:A voluntary anonymous questionnaire was sent to patients by mail including both objective and subjective questions about their level of golf activity and ability both before and after the surgery. MAIN OUTCOME MEASURES/METHODS:Two hundred sixty-eight (73%) patients responded with 35 (34 right-handed and 1 left-handed patients) golfers completing the questionnaire. Results including visual analog pain scores, handicap change, and driving distance were evaluated statistically using the Student t test. RESULTS:Thirty-five golfers at an average time of 3.2 years after TSA completed the questionnaire with 31/35 being able to return to the sport at an average time of 8.4 months postoperatively. Thirty of 31 patients reported improvement in their pain level during and after golfing activity by an average of 4.3 (P < 0.05) on a visual analog scale (VAS) for pain. On average, driving distances increased by 12.5 yd (P = 0.0012) and handicap improved by 1.4 strokes (P = 0.03). CONCLUSIONS:Patients who undergo TSA for primary glenohumeral arthritis can safely return to golfing activity with a significant decrease in their perceived pain level as per VAS scores. Statistically significant findings included an increase in driving distance by 12.5 yd and an improvement in handicap by 1.4. CLINICAL RELEVANCE/CONCLUSIONS:In counseling patients, it is the authors' opinion that based on our experience with golfers undergoing TSA, patients can safely return to sport at an average of 8.4 months. The likelihood of return to play was quite high, but not 100%, and as such no guarantee should be provided to patients. Outcomes of patients with TSA desiring a return to golf are positive, and possible benefits include improvement of pain and possible improvements in driving distance and handicap. LEVEL OF EVIDENCE/METHODS:IV.

BACKGROUND: Knee pain is one of the most common reasons for outpatient visits in the U.S. The great majority of such cases can be effectively evaluated through physical examination and judicious use of radiography. Despite this, an increasing number of magnetic resonance images (MRIs) of the knee are being ordered for patients with incomplete work-ups or for inappropriate indications. We hypothesized that MRIs ordered by orthopaedic providers were more likely to result in changes in diagnoses and/or plans for care than those ordered by non-orthopaedic providers. METHODS: We reviewed the charts of all consecutive new patients seen at our orthopaedic outpatient office between January 1, 2010, and December 31, 2011, with International Classification of Diseases, Ninth Revision (ICD-9) codes for meniscal or unspecific sprains and strains of the knee. A total of 1592 patients met our inclusion criteria and were divided into two groups: those initially evaluated and referred by their primary care physician (PCP) (n = 747) and those initially evaluated by one of our staff orthopaedic surgeons (n = 845). RESULTS: MRI-ordering rates were nearly identical between orthopaedic surgeons and PCPs (25.0% versus 24.8%; p = 0.945). MRIs ordered by orthopaedic surgeons, however, resulted in significantly more arthroscopic interventions than those ordered by PCPs (41.2% versus 31.4%; p = 0.042). Orthopaedic surgeons ordered MRIs for patients who were more likely to benefit from arthroscopic intervention, including patients who were younger (mean age, 45.1 years versus 56.5 years for those with PCP-ordered MRIs; p < 0.001), patients with acute symptoms (39.3% versus 22.2%; p < 0.001), and patients with a history of trauma (49.3% versus 36.2%; p = 0.019). Finally, orthopaedic surgeons were less likely than PCPs to order MRIs for patients with substantial osteoarthritis who subsequently underwent total knee arthroplasty (4.3% versus 9.2%; p = 0.048). CONCLUSIONS: MRI utilization by orthopaedic surgeons results in more appropriate interventions for patients with symptoms and findings most amenable to surgical intervention.

BACKGROUND CONTEXT/BACKGROUND:The intervertebral disc primarily relies on trans-endplate diffusion for the uptake of nutrients and the clearance of byproducts. In degenerative discs, diffusion is often diminished by endplate sclerosis and reduced proteoglycan content. Mechanical loading-induced convection has the potential to augment diffusion and enhance net transport into the disc. The ability of convection to augment disc transport is controversial and has not been demonstrated in vivo. PURPOSE/OBJECTIVE:To determine if loading-induced convection can enhance small molecule transport into the intervertebral disc in vivo. STUDY DESIGN/METHODS:Net transport was quantified via postcontrast enhanced magnetic resonance imaging (MRI) into the discs of the New Zealand white rabbit lumbar spine subjected to in vivo cyclic low rate loading. METHODS:Animals were administered the MRI contrast agent gadodiamide intravenously and subjected to in vivo low rate loading (0.5 Hz, 200 N) via a custom external loading apparatus for either 2.5, 5, 10, 15, or 20 minutes. Animals were then euthanized and the lumbar spines imaged using postcontrast enhanced MRI. The T1 constants in the nucleus, annulus, and cartilage endplates were quantified as a measure of gadodiamide transport into the loaded discs compared with the adjacent unloaded discs. Microcomputed tomography was used to quantify subchondral bone density. RESULTS:Low rate loading caused the rapid uptake and clearance of gadodiamide in the nucleus compared with unloaded discs, which exhibited a slower rate of uptake. Relative to unloaded discs, low rate loading caused a maximum increase in transport into the nucleus of 16.8% after 5 minutes of loading. Low rate loading increased the concentration of gadodiamide in the cartilage endplates at each time point compared with unloaded levels. CONCLUSIONS:Results from this study indicate that forced convection accelerated small molecule uptake and clearance in the disc induced by low rate mechanical loading. Low rate loading may, therefore, be therapeutic to the disc as it may enhance the nutrient uptake and waste product clearance.

The goal of this study was to evaluate the role of portable primary trauma survey radiographs in the evaluation and management of anteroposterior (AP) compression pelvic injuries. A retrospective analysis was conducted at a level I academic trauma center. Twenty-seven adults with AP compressive class pelvic ring injuries who received both portable pelvic radiographs and pelvic computed tomography (CT) imaging in an unbound pelvic state were included. Three orthopedic surgeons performed independent measurements of diastasis on portable pelvic radiographs and coronal pelvic CT reconstructions. Measurement techniques were standardized among observers and were repeated after 8 weeks to assess intraobserver reliability. Nonoperative vs operative treatments were correlated with the initial magnitude of pelvic injury on CT and portable radiographic images. Independent measurements of diastasis on both radiographs and CT scans showed excellent intraobserver reliability (average correlation coefficient, 0.986) and interobserver reliability (average correlation coefficient, 0.979). Compared with diastasis measurements on CT scans, portable pelvic radiographs overestimated diastasis by an average of 49%, or 12.6 mm (P<.0001; 95% confidence interval, 9.6-15.6). Portable pelvic films were less precise than standard pelvic radiographs in measuring the size of femoral head controls (R(2)=0.919 vs 0.759; P=.004). In 12 of the 27 patients evaluated, radiographic indications for operative pelvic fixation were met by portable radiographs but not CT scans, and 11 of these patients ultimately underwent operative fixation. Portable AP pelvic radiographs may distort and exaggerate pelvic bony injuries, especially those involving anterior pelvic structures. Surgeons should use caution when making management decisions based on preliminary portable pelvic radiographs.