Neil P. Sheth

Total Knee Arthroplasty Has Higher Postoperative Morbidity Than Unicompartmental Knee Arthroplasty: A Multicenter Analysis

A total of 2235 primary total knee arthroplasties (TKAs) and 605 unicompartmental knee arthroplasties performed at 3 institutions over 5 years were reviewed to compare the incidence of postoperative complications between these groups. The overall risk of complications for patients undergoing TKA was 11.0%, compared with 4.3% for patients undergoing unicompartmental knee arthroplasty (P < .0001). Total knee arthroplasty was associated with increased rates of manipulation (odds ratio [OR], 13.0; P < .0001), transfusion (OR, 8.5; P = .036), intensive care unit admission (OR, 7.4; P = .049), discharge to a rehabilitation facility (OR, 5.2; P < .0001) and had longer hospital stays (mean, 3.3 vs 2.0 days; P < .0001). There was a trend toward an increased risk of deep infection (0.8% vs 0.2%, P = .13), readmission (4.2% vs 2.7%, P = .0795), thromboembolic events (1.0% vs 0.64%, P = .398), and any reoperation (1.4% vs 0.6%; P = .064). The increased risk of perioperative complications after TKA should be considered when counseling patients if they are an appropriate candidate for either procedure.

Femoral Bone Loss in Revision Total Hip Arthroplasty: Evaluation and Management

&NA; As the number of primary total hip arthroplasty (THA) procedures performed continues to rise, the burden of revision THA procedures is also expected to increase. Proper evaluation and management of acetabular bone loss at the time of revision surgery will be an increasing challenge facing orthopaedic surgeons. Proper preoperative patient assessment and detailed preoperative planning are essential in obtaining a good clinical result. Appropriate radiographs are critical in assessing acetabular bone loss, and specific classification schemes can identify bone loss patterns and guide available treatment options. Treatment options include impaction grafting and cementation of the acetabulum, noncemented hemispheric acetabular reconstruction, structural allograft reconstruction, noncemented reconstruction with modular porous metal augments, ring and cage reconstruction, oblong cup reconstruction, cup‐cage reconstruction, and triflange reconstruction.

Periprosthetic Patellar Fractures

The patella is the largest sesamoid bone in the skeleton. Located within an expansion of the quadriceps tendon, the patella allows an increased functional lever arm of the quadriceps and enhances the mechanical advantage of the extensor mechanism of the knee. In addition, it provides an articulating surface with a low coefficient of friction, protects the native and prosthetic knee from trauma, protects the quadriceps tendon and extensor mechanism from frictional irritation, and affects the cosmetic appearance of the knee1. Because of its biomechanical importance, any problems involving the patella or the patellar component of a total knee prosthesis can have a substantial effect on overall knee function. In fact, patellar complications following total knee arthroplasty have been a well-documented source of discomfort and disability2-6. Although infrequent, periprosthetic fractures of the patella remain a challenge for even the most experienced joint reconstruction surgeons. This is largely due to the discouraging results that are common following the treatment of all but nondisplaced patellar fractures. Even with meticulous anatomic fracture reduction, healing, and reconstitution of the extensor mechanism, return to prefracture function is rare7. …

Prospective Results of Uncemented Tantalum Monoblock Tibia in Total Knee Arthroplasty Minimum 5-Year Follow-up in Patients Younger Than 55 Years

A significant increase in younger patients undergoing total knee arthroplasty raises the theoretical concern for revision secondary to micromotion and fixation failure with cemented components. We prospectively studied 100 consecutive tantalum monoblock uncemented tibial components and 312 concurrent cemented controls. Patients younger than 55 years with adequate bone stock were enrolled. This cementless patient group was younger and had higher preoperative functional status. Prostheses were posterior-substituting uncemented femoral and tibial components with a cemented patellar button. Knee Society pain and function scores and radiographs were obtained, and a cost analysis was performed. Knee Society scores were excellent and equivalent beyond 6 months. There was no significant difference in perioperative blood loss, complication rates, or cost. There was a significant decrease in operative time in the uncemented group. Radiographs revealed no failures of ingrowth at last follow-up. There were 3 uncemented group failures, but none were due to failure of fixation. The use of a porous tantalum tibia at minimum 5 years has yielded promising clinical and radiographic results in a younger patient population.

Modern Total Hip Arthroplasty in Patients Younger Than 21 Years

Total hip arthroplasty (THA) is not commonly performed in adolescents. However, it may be the only option for pain control with continued mobility for advanced disease. We report our experience with modern alternative-bearing THA in patients younger than 21 years. Twenty-one THAs (18 patients) were followed. Preoperative and postoperative Harris hip scores were recorded, and radiographs were reviewed. Average follow-up was 49 months (range, 25-89). Underlying etiology was chemotherapy-induced osteonecrosis (33%), steroid-induced osteonecrosis (29%), sickle cell disease (24%), and chronic dislocation (14%). Articulation bearings were ceramic/ceramic (67%), metal/highly cross-linked polyethylene (29%), and metal resurfacing (5%). Mean age was 18 years (range, 13-20). Harris hip scores improved from 43.6 to 83.6 (P < .001). At final follow-up, there was no radiographic loosening; 1 THA was revised for a cracked ceramic liner. At intermediate-term follow-up, clinical and radiographic results are favorable after alternative-bearing THA in patients younger than 21 years.

Rhabdomyolysis and acute renal failure following arthroscopic knee surgery in a college football player taking creatine supplements.

We describe a college football player and weight-lifter who unexpectedly developed rhabdomyolysis and nonoliguric acute renal failure (ARF) following arthroscopic knee surgery. There was swelling and pain without evidence of a compartment syndrome postoperatively. The patient reported that he was an avid weight-lifter and that he was taking up to 10 g/d of a creatine supplement during the 6 weeks prior to this surgery. His ARF resolved over several days, with a peak serum creatinine of 2.3 mg/dl and peak creatine kinase (CK) of 194,000 U/l, following administration of intravenous fluids, mannitol, and sodium bicarbonate. Given the rarity of clinically significant rhabdomyolysis with this type of operation, we suggest that the patients use of creatine increased the risk of skeletal muscle injury due to ischemia from intra-operative tourniquet application.

Operative treatment of early peri-prosthetic femur fractures following primary total hip arthroplasty.

The risk factors for and results of operatively treated peri-prosthetic femoral fractures sustained within 90 days following primary THA were evaluated. 5,313 consecutive THAs were reviewed and 32 (0.60%) fractures were identified which included 9 A(g), 2 B(1), 18 B(2), 1 B(3), and 2 A(g)/B(2) fractures. 19 (61%) patients sustained 23 complications including 9 greater trochanter non-unions, 2 femoral shaft non-unions, 3 patients with Brooker III HO, and 2 deep infections. 7 patients (23%) required a second operative procedure and one patient required a third. Peri-prosthetic fractures were associated with advancing age, female gender, developmental hip dysplasia, and cementless metaphyseal engaging components, particularly flat wedge tapers. Overall, operative treatment of acute peri-prosthetic fractures is associated with a high rate of complications (61%) and re-operation (23%).

DVT prophylaxis in total joint reconstruction.

Deep venous thrombosis (DVT) is the end result of a complex interaction of events including the activation of the clotting cascade in conjunction with platelet aggregation. Patients undergoing major lower extremity orthopedic surgery, especially total joint arthroplasty (TJA), are at high risk for developing a postoperative DVT or a subsequent pulmonary embolus. Venous thromboembolic (VTE) prophylaxis, most commonly pharmacologic prophylaxis, has become the standard of care for patients undergoing elective TJA. However, the controversy between the efficacy of VTE prophylaxis and the increased risk for bleeding in the postoperative period continues to exist. This review addresses the controversy underlying VTE prophylaxis by outlining 2 guidelines and demonstrating the pros and cons of different DVT prophylaxis regimens based on the available evidence-based literature.

A comparative evaluation of halo pin designs in an immature skull model.

To design an improved halo pin for use in pediatric patients, three commonly used halo pins were evaluated with a mechanical testing apparatus and segments of prepared fetal calf skull. The pins were driven through the bone segments while the load at the bone-pin interface was measured. New pins were designed with respect to pin tip and flange width and similarly compared. Mean maximum loads to penetration, normalized for bone segment thickness, were 55.6 N/mm for the PMT Corporation pin, 61.5 N/mm for the Bremer pin, and 73.6 N/mm for the Ace pin. Four new, short tipped pins were designed and compared with the Ace pin, and there was no significant difference. Finally, four new pins were designed with varying flange widths. Mean maximum loads, normalized for bone segment thickness, were 68.9 N/mm for the 4.2 mm flange, 72.2 N/mm for the 4.7 mm flange, 92.9 N/mm for the 5.2 mm flange, and 96.4 N/mm for the 5.7 mm flange. The findings of this investigation are clinically important because they may help to explain the variability in the complication rates seen with the use of different halo systems in children. The three halo pins currently on the market have different pin designs, including tip lengths and flange distances, which contribute to the difference in load to penetration for each pin. The new, wide flanged, short tipped halo pin design might decrease the complication rate of halo use in children by providing an improved capacity to resist penetration despite increased loads of application.

Acetabular distraction: an alternative for severe acetabular bone loss and chronic pelvic discontinuity.

Acetabular bone loss is a challenging problem facing the revision total hip replacement surgeon. Reconstruction of the acetabulum depends on the presence of anterosuperior and posteroinferior pelvic column support for component fixation and stability. The Paprosky classification is most commonly used when determining the location and degree of acetabular bone loss. Augments serve the function of either providing primary construct stability or supplementary fixation. When a pelvic discontinuity is encountered we advocate the use of an acetabular distraction technique with a jumbo cup and modular porous metal acetabular augments for the treatment of severe acetabular bone loss and associated chronic pelvic discontinuity.