Lawrence M. Specht

Complications of Femoral Nerve Block for Total Knee Arthroplasty

AbstractPreemptive and multimodal pain control protocols have been introduced to enhance rehabilitation after total knee arthroplasty (TKA). We determined the complication rate associated with preoperative femoral nerve block (FNB) for TKA. Among 1018 TKA operations, we performed 709 FNBs using a single-injection technique into the femoral nerve sheath and confirming position with nerve stimulation before induction. After TKA, weightbearing as tolerated was initiated using a walker or crutches on postoperative Day 1. Twelve patients (1.6%) treated with FNB sustained falls, three (0.4%) of whom underwent reoperations. Five patients had postoperative femoral neuritis, which may have been secondary to the block. One patient had new onset of atrial fibrillation after FNB, and the TKA was postponed. Femoral nerve block before TKA is not a harmless intervention. We recommend postoperative protocols be modified for patients who have FNB to account for decreased quadriceps function in the early postoperative period, which can lead to falls. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Diabetes mellitus, hemoglobin A1C, and the incidence of total joint arthroplasty infection.

Patients with diabetes have a higher incidence of infection after total joint arthroplasty (TJA) than patients without diabetes. Hemoglobin A1c (HbA1c) levels are a marker for blood glucose control in diabetic patients. A total of 3468 patients underwent 4241 primary or revision total hip arthroplasty or total knee arthroplasty at one institution. Hemoglobin A1c levels were examined to evaluate if there was a correlation between the control of HbA1c and infection after TJA. There were a total of 46 infections (28 deep and 18 superficial [9 cellulitis and 9 operative abscesses]). Twelve (3.43%) occurred in diabetic patients (n = 350; 8.3%) and 34 (0.87%) in nondiabetic patients (n = 3891; 91.7%) (P < .001). There were 9 deep (2.6%) infections in diabetic patients and 19 (0.49%) in nondiabetic patients. In noninfected, diabetic patients, HbA1c level ranged from 4.7% to 15.1% (mean, 6.92%). In infected diabetic patients, HbA1c level ranged from 5.1% to 11.7% (mean, 7.2%) (P < .445). The average HbA1c level in patients with diabetes was 6.93%. Diabetic patients have a significantly higher risk for infection after TJA. Hemoglobin A1c levels are not reliable for predicting the risk of infection after TJA.

A Comparison of Acetate vs Digital Templating for Preoperative Planning of Total Hip Arthroplasty: Is Digital Templating Accurate and Safe?

The purposes of this study were to compare the accuracy of acetate and digital templating for primary total hip arthroplasty (THA) and to determine if digital templating is safe. Preoperative planning was performed on 50 consecutive preoperative radiographs during 2005. Templating results were compared with the actual hip implants used. Interrater reliability of acetate templating and accuracy of acetate and digital templating were recorded. Digital measurement overestimated acetabular size (P < .001) and underestimated the femoral size (P = .03). The absolute errors were larger for digital compared with acetate templating; however, mean absolute errors did not differ significantly (acetabulum, P = .090; femur, P = .114). Acetate and digital templating can accurately predict the size of THA implants. Digital templating was determined to be acceptably safe for preoperative planning of primary THA operations.

Pneumatic compression hemodynamics in total hip arthroplasty

A crossover study was performed to evaluate the effect of several pneumatic compression devices and active dorsoplantar flexion in 10 patients who underwent total hip arthroplasty. Using the Acuson 128XP/10 duplex ultrasound unit with a 5-MHz linear array probe, peak venous velocity and venous volume were assessed above and below the greater saphenous vein and common femoral vein junction. A computer generated randomization table was used to determine the order of the test conditions. The pneumatic compression devices evaluated included two foot pumps, one foot and calf pump, one calf pump, and three calf and thigh pumps. Statistical analyses included analysis of variance and analysis of variance with covariance between devices and patients. The covariates tested were the baseline measurements and the order in which the devices were tested. Differences between devices relate in part to the frequency and rate of inflation and the location and type of compression. Pulsatile calf and foot and calf pneumatic compression with a rapid inflation time produced the greatest increase in peak venous velocity, whereas compression of the calf and thigh showed the greatest increase in venous volume. Because patient and nursing compliance is essential to the success of mechanical prophylaxis for thromboembolic disease, the more simple, yet efficacious, devices that are easier to apply and less cumbersome appear to have a greater likelihood of success. In the active and alert patient, active dorsoplantar flexion should be encouraged.

Prospective, randomized comparison of cobalt-chrome and titanium trilock femoral stems.

The purpose of this article was to demonstrate the efficacy of a cementless, flat, tapered wedge femoral stem and compare cobalt-chrome and titanium femoral stems with this design. Three hundred ninety femoral stems observed for a mean of 4.7 years (2.0-8.9 years) were prospectively evaluated with clinical and radiographic follow-up. Hips were stratified by Dorr classification, bone stock (femoral index), size of implant used, and material of femoral implant. Survivorship of the femoral stem at 8.9 years was 99.8% with no significant difference between cohorts. Thigh pain (4.9%) was more common with cobalt-chrome femoral stems (6.5%) than titanium femoral stems (3.1%). The flat, tapered wedge femoral stem design provides excellent femoral reconstruction in total hip arthroplasty. On the basis of this study, we use titanium femoral stems.

Cementless acetabular fixation with and without screws: analysis of stability and migration.

The purpose of this study was to compare initial stability and late migration of 775 cementless acetabular components with and without screw fixation. Screw fixation was used in 509 cups and no screws in 266 cups. Average follow-up in the screw fixation group was 6.32 years (range, 2-10 years) and 6.9 years (range, 2-10 years) in the no-screw group. One component (0.2%, osteolysis) in the screw group and one (0.4%, loss of fixation) in the no-screw group required revision. Osteolytic lesions more than 4 cm(2) were noted in 8 (1.6%) screw fixation cups and 2 (0.75%) no-screw fixation cups. No cups in either cohort had radiographic evidence of migration. Screw fixation did not have a favorable or adverse effect on the outcome of acetabular reconstruction.

The effect of EPSTR and minimal incision surgery on dislocation after THA.

Dislocation rates after posterior approach THA have decreased with the advent of enhanced posterior soft tissue (EPSTR) repairs that incorporate the external rotators. We examined three posterior approaches (simple posterior repair, EPSTR, and posterior minimal incision surgery using enhanced posterior soft tissue repair) performed by one surgeon in 390 consecutive primary THA operations (390 patients) from 1992-2003. A simple posterior repair of the external rotators done through three drill holes was performed in the first 90 patients. EPSTR incorporating the external rotators and posterior capsule in one continuous sleeve was performed in 180 patients. A 10 cm mini incision with EPSTR was performed in 120 patients. The overall dislocation rate for the series was 2.3% (9 of 390 procedures) with a 1% (4 of 390 procedures) revision rate for dislocation. The simple repair group had a greater dislocation rate (5.5%) compared to the group with EPSTR (1.3%) and the minimal incision with EPSTR group (1.7%). EPSTR decreased dislocation after total hip arthroplasty performed with a posterior approach. A 10 cm mini incision posterior approach with EPSTR maintained the low dislocation rate. Revision rate for dislocation was equivalent between the 3 groups.Level of Evidence: Therapeutic study, level III (retrospective comparative study). See Guidelines for Authors for a complete description of levels of evidence.