Faculty Bibliography

Introduction/UNASSIGNED:Preliminary analysis of accelerometry measurements has shown physical activity may not increase significantly after total knee arthroplasty (TKA). This study evaluates the effect of TKA on physical activity accelerometry measurements and body mass index (BMI). Methods/UNASSIGNED:tests. Results/UNASSIGNED:Twenty-three patients from the OAI database were identified for the paired analysis. They were evaluated at a mean postoperative follow-up of 15 months. There were no statistically significant differences between the post-TKA group and pre-TKA group for the accelerometry variables and BMI, though patients experienced a significant improvement in knee function and pain relief measures included in this analysis. Discussion/UNASSIGNED:Although TKA can successfully restore function and relieve pain, there remains no good evidence that neither physical activity nor BMI improve postoperatively. Conclusion/UNASSIGNED:No significant differences in physical activity and BMI were observed after TKA in this study.

Interprosthetic femur fractures are a rare but serious complication following total hip and knee arthroplasty. Classification systems have focused not only on diagnosis but also on treatment algorithm. Critical to the evaluation of patients with these fractures are an assessment of fracture location, bone quality, and the presence of stemmed implants. The gold standard for fracture fixation is locked plating with bicortical and unicortical screws, supplemented with wires or cables as needed. For patients with compromised bone stock or insufficient bony area for fixation, allograft augmentation with struts or interprosthetic sleeves may be used. For fractures with severe bone loss, conversion to a megaprosthesis or total femur replacement may be warranted.

Two-stage exchange is most commonly used for treatment of prosthetic joint infections (PJI) but, this may fail to eradicate infections. C-reactive protein/albumin ratio (CAR) has been used to predict survival and operative success in other surgical subspecialties and so, we assess the association between CAR and reimplantation success during two-stage revision for PJI defined by the Musculoskeletal Infection Society following a primary total hip (THA) or knee (TKA) arthroplasty. From January, 2005 to December, 2015, two institutional databases were queried and patient demographics, antibiotic duration, C-reactive protein, and albumin were collected prior to reimplantation. Two-stage revisions were considered successful if patients were off of antibiotics and did not require a repeat surgery. CAR was available for 79 patients (34 hips and 46 knees) with 61 successful two-stage revisions and 18 failures. The average CAR for patients with successful reimplantation was 1.2 (0.2, 3.0) compared to 1.0 (0.4, 3.2) for treatment failure. However, this was not statistically significant (p=0.766). Therefore, CAR is not applicable in predicting the prognosis of two-stage revisions for PJI in total arthroplasty but other preoperative inflammatory-based prognostic scores should be explored.

Acute kidney injury is a reported complication of total joint arthroplasty (TJA), with potentially severe long-term complications. Our study aimed to identify the rate of perioperative renal injury in patients without pre-existing renal dysfunction who undergo TJA. Using the American College of Surgeons National Surgical Quality Improvement Program database, we identified a mean annual rate of perioperative renal injury of 0.172% between 2009 and 2015. Factors most strongly associated with perioperative renal injury are age of 70 years or older, current smoking, history of diabetes mellitus, history of hypertension, and American Society of Anesthesiologists class of 3 or greater. There was no significant increase in the rate of renal injury from year to year. In patients without pre-existing renal disease, perioperative rates of acute kidney injury remain low in patients undergoing TJA.

Vascular complications in revision total hip arthroplasty may occur in cases where the components of the hip implant migrate through the acetabular wall, through the iliopectineal line of the pelvis, and into the pelvic cavity. This migration may lead to substantial intrapelvic vascular compromise, drastically increasing the surgical complexity and potential risk for morbidity and mortality in these surgical cases. Here, we present a case of a 78-year-old woman with significant acetabular protrusio, which resulted in intraoperative compromise of the external iliac artery with rapid extravasation. As a result of prudent preoperative planning, interdisciplinary collaboration, and precautionary measures, significant patient morbidity and mortality was averted.

Increasingly the relationship between the hip and spine has become recognized as a risk factor for postoperative instability following total hip arthroplasty. Thorough understanding of the relationship between the spine and pelvis, spinopelvic parameters, and normal and pathologic spinopelvic motion is critical to surgical planning and prevention of instability after total hip arthroplasty. This review details spinopelvic motion and postural changes that predispose patients to instability, guides readers through a preoperative risk assessment tool and our stepwise protocol to classify spinopelvic motion and prevent instability.
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