Introduction: Clinical experience has shown that addressing variations in bone morphology is important in the development of successful hip implant designs. Numerous studies of femoral bone morphology have been published utilizing various techniques. This study has developed a method which consistently measures large quantities of 3-dimensional digital femura geometry segmented from computed tomography (CT) scans and can accurately make anatomical measurements from these images

Methods: CT images of left femora on five hundred fifty six left femura (57% male, 43% female), consisting of 69% Caucasian, 16% Asian and 14% unknown were analyzed. The average age was 66 years, ranging from 40 to 93 years. Segmentation of the outer cortical, inner cortical, and marrow boundaries were consistently performed over all CT scans. The positions identified on the reference bone are transformed to the equivalent position on the clinical bone images, from which the dimensional data is extracted and stored. The mediolateral width (MLW), medial offset (MO) and lateral offset (LO) were measured in 10mm increments, ranging from 20mm above the lesser trochanter (LT) to 130mm below the lesser trochanter. The canal flare index was defined as a ratio of the mediolateral width at a section 20mm above the lesser trochanter to the mediolateral width at the isthmus level.

Results: The mean mediolateral width at 20mm above the lesser trochanter was 47.0 ± 4.5 (35.1–61.8; n=556). Noble reported 45.4 ± 5.3 (31.0–60.0; n=200), Husmann reported in a neck oriented study 46.3 ± 6.9 (27.6–63.6; n=310) and Laine reported 47.1 ± 4.9 (n=50). The mean medial offset at a section 20mm above the lesser trochanter was 25.1 ± 2.9 (16.7–33.4). In the study by Husmann, a mean of 25.0 ± 5.2 (9.4–45.5) was reported. The mean canal flare index was 4.49 ±.8. Noble reported a mean canal flare index of 3.80 ±.074, Husmann 3.81 ±.83 and Laine 4.3 ±.93.

Discussion: In general, the study showed minor differences to published data of proximal bone morphology. However, this more powerful study has shown that there is a higher mean canal flare index than determined by Noble and a similar mean canal flare index as determined by Laine. As reported by Laine, the canal flare index varies significantly with the placement of measurements in the canal. In this study the measurements were performed in a plane oriented by the femoral neck as a hip stem would be placed. The CFI over the isthmus width showed a greater correlation than previously shown by Noble. The novel software tool allows for anatomical measurements that can be applied to an unlimited population size enabling further applications and studies.

Background: Vascular injuries associated with total joint arthroplasty are the most feared complication. The arterial and venous injury can occur due to direct or indirect trauma. A high index of suspicion, recognition of the injury and prompt treatment, with the immediate availability of a vascular surgeon is vital for good outcome.

Methods: Using prospectively collected data on 13624 patients undergoing total joint arthroplasty at our institution, all incidences of vascular injury were identified. Detailed data regarding the mode of presentation, the type and the outcome of intervention delivered, and the eventual functional outcome of the total joint arthroplasty were determined.

Results: There were a total of 17 vascular injuries (0.1%). Majority (16/17) of these vascular injuries were detected in the postoperative recovery area. 9 injuries occurred after TKA and 8 occurred after THA. Indirect injury was the mechanism in TKA patients with popliteal artery thrombosis being the mechanism. In contrast direct injury was the mechanism in THA patients. Fasciotomy was performed in all TKA patients and none were needed in the THA patients. One patient died of complications related to vascular injury. 12 of 17 patients (70%) had launched a legal suit against the operating surgeon.

Conclusions: After more than 80 years of accumulated experience and more than 35000 joint replacements performed by 5 surgeons in our center, the vascular complication still continues to occur. Patient awareness regarding this real problem may play a role in defraying the extremely high likelihood of legal suits associated with this complication.

Introduction: Many patients with DJD of the hip may have co-existent spinal arthritis. This prospective study sought to determine: how hip arthritis commonly presents, the incidence of low back pain- as identified by patients- before and after THA and the correlation between LBP and hip arthritis.

Methods: 344 consecutive patients undergoing THA were recruited prospectively at a single institution. A detailed questionnaire containing diagrams on which the patient could draw out the site of their pain was administered to all patients preoperatively and postoperatively. Detailed clinical, radiographic, and cross sectional imaging of all the patients were reviewed in detail by a hip surgeon, a spine surgeon, and a neurologist.

Results: 170 patients (49.4%) had true LBP which resolved in 63 patients (37%). Of the remaining 107 patients the back pain was of the same intensity following THA in 33 patients (30%) and had decreased in 74 (70%) patients. 22 of the 33 patients with continued LBP were known to have spine pathology. 35 patients developed LBP after THA.18 patients in the latter group were investigated further and 12 were found to have severe previously unrecognized spine pathology.

Discussion: Hip and spine arthritis often co-exist. Majority of patients with ‘back’ pain experience a complete resolution of their pain following THA so long as prior spine pathology did not exist. THA seems to be beneficial in reducing the symptoms even for those with a pre-existent LBP and spine pathology. A number of patients may develop LBP following THA that may relate to unidentified spine pathology. Patients with true LBP may benefit form evaluation of their spine prior to THA.

Introduction: Pulmonary embolism (PE) is a potentially fatal complication of total joint arthroplasty (TJA). Therefore, reliable means for diagnosis and evaluation of severity is essential. This study evaluates the reliability of common clinical signs and symptoms in the diagnosis of PE. In addition, clinical presentation is correlated with size and location of emboli within the pulmonary vasculature (segmental, lobar, or main).

Methods: The clinical and imaging records of all patients with confirmed diagnosis of PE following TJA performed between 2000 and 2004 were reviewed in detail. The mode of presentation and the subsequent imaging findings were noted.

Results: A total of 132 confirmed PE cases were studied. Clinical presentation included dyspnea (19.7%), chest pain (7.6%), change of mental status (6.8%0, hypotension (6.1%), and diaphoresis (3.8%). Mean room air pulse-oximetry was 85.5%. Arterial sampling showed mean O2 saturation of 88.1% and pO2 of 58.7. There was not a direct correlation between the size of the PE and the clinical presentation. However, there was a correlation between the severity of oxygen desaturation and the size and location of the embolus.

Conclusions: The presentation of PE can be non-specific and highly variable ranging from mild dyspnea to catastrophic hemodynamic collapse. Common clinical signs have a low sensitivity for diagnosis and do not correlate with severity of disease. The only correlation seemed to be measured arterial O2 saturation and pressure. Thresholds for the diagnosis of clinically significant pulmonary embolisms need to be established to improve management of this important condition.

Introduction: The use of coumadin for prophylaxis against thromboembolism (TE) following total joint arthroplasty is the standard of care. In light of recent publication of the American College of Chest Physicians (ACCP), we altered our anticoagulation protocol to be compliant with the recommendations. This study evaluates the incidence of TE and bleeding complications following TJA when low dose coumadin vs. regular dose coumadin was administered.

Methods: 987 consecutive patients undergoing total joint arthroplasty by a single surgeon between the years of 2004–2005 were included. 446 patients operated on during the 2004 received low dose coumadin (intended INR 1.5–1.7) whilst 541 patients undergoing TJA during 2005 were given regular dose coumadin (intended INR 2–2.5).

Results: The mean INR for patients operated during the year 2005 was significantly higher than the INR for patients receiving TJA in 2004. There were more complications in 2005. There were 13 PE, 44 wound drainage, 4 DVT, and 11 hematoma formation (requiring surgical evacuation) during the year 2005 compared to 10 PE, 26 wound drainage, 6 DVT, and 5 hematoma formation in 2004. The difference for all complications except DVT was significant.

Conclusion: This study confirms the commonly held belief that aggressive anticoagulation does carry a higher incidence of complications such as wound drainage and bleeding. It appears that administering higher dose coumadin increased the bleeding complications without conferring additional protection against thromboembolic disease.

Introduction: The potential benefits of Minimally invasive total hip arthroplasty (MIS THA) continues to be heavily debated. We hypothesized that the potential benefits of MIS THA may relate to factors such as patient selection, patient preconditioning, improvements in anesthesia technique, pain management, and not the incision size. This randomized, prospective study was designed to investigate the role of these confounding factors in general and aggressive rehabilitation in particular on the outcome of THA.

Methods: 100 patients undergoing THA at our institution were randomized into one of four groups. Group A was patients who had standard THA (incision length> 10 cm) and received standard preoperative and postoperative care. Group B patients had THA using small incision (< 10 cm) and standard protocols. Group C patients had regular incision THA, but received aggressive rehabilitation and pain control regimen. Group D patients had THA through small incision and received aggressive regimen.

Results: The demographic distribution amongst all the groups was similar. There was a significant improvement in function as measured by Harris Hip Score, LASA (validated rehabilitation score), SF-36, and lower extremity function test in all groups. The extent of functional improvement, home discharge, patient satisfaction, and analgesia requirement was better in patients who received aggressive preoperative and postoperative care regimen regardless of the size of their incision. There was no difference in estimated blood loss, mean operative time, transfusion needs, and complications between the groups.

Discussion: This study highlights the importance of family education, patient conditioning, pre-emptive analgesia, and aggressive preoperative and postoperative rehabilitation in influencing the outcome of THA. The aforementioned factors, and perhaps not the surgical technique per se, may play a major role in imparting advantageous outcome to MIS THA that is reported by various investigators.

Introduction: A small, yet not uncommon, problem following total joint arthroplasty (TJA) is post-operative ileus (POI). The purpose of this study was two-fold. First the study sought to determine the incidence of POI after TJA in a consecutive series of patients receiving regional anesthesia and an aggressive postoperative rehabilitation protocol. Second, the influence of narcotic medications, including intrathecal medications, in the incidence of POI was examined.

Methods: 5,262 patients underwent total joint replacements, including primary and revision surgery, at our institution from 2004 to 2005. All surgeries were performed at a university-affiliated institution where complications, if any, are prospectively recorded in a comprehensive database. Demographic, clinical, surgical, and radiographic details were obtained and examined.

Results: 26 (0.5%) patients developed ileus. There were 17 males and 9 female patients, who had a mean age of 67.7 years (range, 52.7 to 91.2 years). The mean BMI was 30.2 kg/m2. The index procedures included 15 primary hip, 4 primary knee, 4 revision hip, and 3 revision knee procedures. Of the patients who developed ileus, intrathecal narcotics were administered in 16 patients (62%).

Discussion: There is a very low incidence of postoperative ileus and gastrointenstinal hypomobility following joint arthroplasty. Early patient ambulation, a reduction in the use of postoperative narcotics, supplementation of analgesia with non-narcotic drugs, and reduced length of hospital stay may all have an important role in reducing this complication. Based on our findings, it seems unlikely that intrathecal narcotics have an adverse effect on gastrointestinal motility.

Background: Total joint arthroplasty (TJA) is a successful procedure. With the demographic tendency towards an elderly society and a relatively high prevalence of arthritis, the number of joint replacement in the US will increase dramatically in the upcoming years. The orthopaedic surgeons need to be aware of the various types of complications in the early hospital setting associated with elective TJA.

Methods: This prospective study reviewed the systemic and local early complications occurring after 13133 TJA which included 7,438 hip arthroplasties (6,010 primary and 1,428 revisions) and 5,695 knee replacements (4,944 primary and 751 revisions). A standardized and detailed form intended to capture all medical and orthopedic complications was devised, plus a full-time research fellow was dedicated to this study. The hospital course of every patient was followed on a daily basis closely. The circumstances leading to the complications and the details of the therapeutic intervention for each complication were recorded.

Results: In general the incidences of complications were higher following TKA compared to THA. There was 26(0.19%) deaths in the cohort that occurred within 10 days after surgery. 329 major (life threatening) complications occurred in the cohort that included myocardial infarction (36), hypotensive crisis (11), pulmonary embolus (145), tachyarrhythmia (93), pulmonary edema (10), acute renal failure (24), stroke (6), bowel obstruction or perforation (3), and pneumothroax (1). There were 37 major local complications. 301 (91%) of these complications occurred within 4 days of index surgery. There were 453 minor systemic complications, mostly related to anemia, and 99 minor local complications in this cohort.

Conclusions: Total joint arthroplasty despite its success can be associated with serious and life threatening complications. The introduction of MIS surgery and the potential for very early discharge of patients undergoing arthroplasty needs to be scrutinized in light of these findings.