Introduction and Aims: With interest in minimally invasive surgery, and smaller incisions for total hip arthroplasty (THA), ways to ensure appropriate alignment are critical. Femoral stem varus has been associated with poorer results. We report the incidence of varus placement of a tapered, proximally plasma-sprayed, titanium femoral component and describe the outcomes of varus at minimum five-year follow-up.

Method: Between 1986 and 1997, 1080 tapered, proximally plasma-sprayed femoral components were implanted in primary cementless THA at one institution. Twenty-six components in 25 patients were placed in five degrees or more of varus. Two patients were lost to follow-up. The need for further surgery was assessed and Harris hip scores evaluated.

Results: Harris hip scores improved an average of 44 points. All femoral components were judged to be osteo-integrated. There was no displacement or progression into further varus, or impending failures. One well-fixed stem was revised at an outside institution for unexplained pain at 2.5 years. Survival with aseptic loosening as an end-point is 100 percent. Overall survival of the femoral component is 96 percent at 10 years average follow-up.

Conclusion: As visualisation decreases with decreasing incision length, a component that is reliably placed into appropriate position is required. Implant position with this component is forgiving. It may be an excellent choice for less-invasive techniques with compromised visualisation. In varus, the stem performs well, with no revisions for aseptic loosening and a 96 percent survival at up to 16 years.

Introduction and Aims: Adequacy of post-operative pain control can effect total knee arthroplasty (TKA) outcomes. We examine the effectiveness of a simple and inexpensive method using long-acting local anesthetic (bupivacaine) with epinephrine and morphine injection on controlling pain, blood loss, and motion in primary TKA.

Method: We retrospectively reviewed 170 patients who underwent 208 primary TKA, by a single surgeon between October 2001 and December 2002. The control group of 75 patients (99 knees) had received no intra-operative injections. The study group of 95 patients (109 knees) had received intra-operative injection of 0.25 percent bupivacane with epinephrine and morphine divided two-thirds soft-tissue injection and one-third intra-articular injection. Bilateral simultaneous TKA in the study group received a divided anaesthetic dose.

Results: The control group required significantly more breakthrough narcotic (85 percent vs 67 percent; p=0.004); and required more narcotic reversal for over-sedation. The study group had significantly higher ROM at discharge 63 degrees vs 52 degrees. Lower ROM at discharge was associated with manipulation (p equals 0.001). The study group required less transfused blood (mean 0.03 vs 0.1 units), and had significantly lower bleeding indices 2.7 vs 3.5.

Conclusion: Preemptive analgesia with intra-articular and soft-tissue injection of long-acting local anesthetic with epinephrine and morphine appears to decrease need for rescue narcotics and reversal agents. The use of the injection also increases ROM at discharge, which reduces the need for manipulation. Lastly, the bleeding index and transfusion requirements are significantly reduced. This inexpensive method is effective in improving the post-operative course of primary TKA.

Introduction: Previously, in vivo kinematic studies have determined the in vivo kinematics of the femur relative to the metal base-plate. These kinematic studies have reported posterior femoral rollback in posterior stabilized (PS) TKA designs, but the actual time of cam/post engagement was not determined. The objective of this present study was to determine, under in vivo conditions, the time of cam/post engagement and the kinematics of the femur relative to the polyethylene insert.

Methods: Femorotibial contact positions for twenty subjects having a PS TKA, implanted by two single surgeons, were analyzed using video fluoroscopy. Ten subjects were implanted with a PS TKA that is designed for early cam/post engagement (PSE) and ten subjects with a PS TKA designed for later cam/post engagement (PSL). Each subject, while under fluoroscopic surveillance, performed a weight-bearing deep knee bend to maximum flexion. Video images were downloaded to a workstation computer and analyzed at ten-degree increments of knee flexion. Femorotibial contact paths for the medial and lateral condyles, axial rotation and condylar lift-off were then determined using a computer automated model-fitting technique.

Results: Subjects implanted with the PSE TKA experienced, on average, the cam engaging the post at 48° (10 to 80°). Subjects having the PSL TKA experienced more consistent results and did experience engagement in deep flexion (Average 75°). Subjects having the PSE TKA experienced, on average, −5.5 mm (1.5 to −9.3) of posterior femoral rollback (PFR), while subjects having the PSL TKA experienced only −2.6 mm (8.5 to −9.0) of PFR. Subjects having the PSE TKA experienced more normal axial rotation patterns. Nine subjects having the PSE TKA experienced condylar lift-off (maximum = 1.9 mm), while only 4/10 having the PSL TKA experienced condylar lift-off (maximum = 2.7 mm).

Discussion: This is the first study to determine the in vivo contact position of the cam/post mechanism. Subjects having a PSE TKA experienced earlier cam/post engagement than subjects having the PSL TKA. Some subjects did not experience any cam/post engagement throughout knee flexion. Subjects having the PSE TKA experienced more PFR and better axial rotation patterns, but subjects having a PSL TKA experienced lesser incidence of condylar lift-off. Results from this study suggest that there may be an advantage to early cam/post engagement, which leads to more normal axial rotation patterns caused by the medial condyle moving in the anterior direction as the lateral condyle rolls in the posterior direction.