The Effect of Postoperative Sleeping Position on Knee Extension and Range of Motion Following Primary Total Knee Arthroplasty.

Total knee arthroplasty (TKA) is an orthopaedic operation that improves quality of life and reduces pain in patients with disabling arthritis of the knee. One commonly recognized complication is flexion contracture of the knee. Early physical therapy helps prevent flexion contracture and improve range of motion (ROM) postoperatively. This study evaluated postoperative sleeping position and its effect on terminal knee extension and ROM following primary TKA. We hypothesized that patients who slept in the supine position would achieve earlier knee extension and greater ROM when compared to those in the lateral recumbent position. A total of 150 consecutive primary TKAs were performed by a single surgeon (J.M.C.) from April 2014 to December 2014. The data were collected prospectively to determine preoperative ROM, postoperative ROM, and sleeping position. Mean postoperative terminal extension ROM at 1 month was 2.9 degrees in the supine group versus 6.0 degrees (p< .001) in the lateral group. No significant demographic differences between the two groups at baseline were found. Our results demonstrate that sleeping position affects initial postoperative terminal extension, however, not overall ROM. We found a statistically significant difference in extension when comparing patients in the supine versus lateral group. Patients who slept in the lateral position lacked 6 degrees of extension which is greater than the 5 degrees needed for normal gait mechanics. Those in the supine group lacked 2.9 degrees of extension, allowing for normal gait mechanics. This study identifies an easy, effective means of increasing patients initial ability to achieve knee extension and satisfaction following TKA.

Efficacy of Tourniquet Use in Total Knee Arthroplasty: A Retrospective Cohort Review.

Background: The use of a tourniquet has become widely accepted as standard practice during total knee arthroplasty (TKA). There are conflicting outcomes in using a tourniquet during TKA. This brings to question the role a tourniquet has in TKA. Therefore, we conducted a retrospective cohort study to examine the effects of TKA with and without the use of a tourniquet. Methods: A total of 120 patients (n = 60 underwent TKA with tourniquet and n = 60 underwent TKA without tourniquet) were included in this study. Patient medical records were retrospectively reviewed for preoperative and postoperative data. The Gross formula, a validated formula for calculating blood loss, was used to calculate each patient's total blood loss. Statistical analysis was performed using independent t-tests, Mann-Whitney U tests, and/or chi-square tests. Significance was determined using an alpha level of P < .05. Results: There was no statistically significant difference (P = .49) in the amount of total blood loss between patients undergoing TKA with a tourniquet and those without (199.6 ± 92.2 mL vs 211.1 ± 88.1 mL, respectively). However, there were statistically significant differences in the operating room time (P = .005), surgery time (P = .008), and functional return of postoperative straight leg raise (P < .001) between groups. Conclusions: This study supports existing evidence that tourniquet use during TKA does not significantly alter blood loss and presents evidence that using a tourniquet during TKA may add additional cost and increase surgical time without benefit.

Failure of Screw/Shell Interface in the Trident II Acetabular System in Total Hip Arthroplasty.

We report a case series of 2 patients with screw/shell interface failure in the Stryker Trident II Acetabular System. Both failures consisted of screw penetration through the Trident II acetabular shell. One failure was observed postoperatively after a revision from a cephalomedullary nail to a total hip arthroplasty while the other was observed intraoperatively during a primary total hip arthroplasty. Both component failures were managed conservatively with weight-bearing as tolerated and radiographic monitoring. These are the first reported cup/screw failures of the Stryker Trident II system and should raise awareness of the potential complication and implant design flaw. When placing acetabular screws, we recommend obtaining intraoperative orthogonal screw radiographs that are tangential to the shell surface to assess for screw/shell failure.

Catastrophic failure of a dual mobility bearing in a revision total hip arthroplasty.

The following case demonstrates an example of a catastrophic failure of a dual mobility (DM) bearing used in the setting of a revision total hip arthroplasty for an acetabular component with an excessive abduction angle. Currently, in the literature, it has been demonstrated that DM bearings have decreased polyethylene wear at abduction angles up to 65°; however, this has only been shown in in vitro studies. To our knowledge, there have been no reports of in vivo DM bearings that have demonstrated these same results. In this case, a DM bearing was used in a revision surgery with a retained acetabular component that had an abduction angle of approximately 70°-75° which ultimately led to catastrophic polyethylene failure.