Alignment in total knee arthroplasty : what’s in a name?

Dissatisfaction following total knee arthroplasty is a well-documented phenomenon. Although many factors have been implicated, including modifiable and nonmodifiable patient factors, emphasis over the past decade has been on implant alignment and stability as both a cause of, and a solution to, this problem. Several alignment targets have evolved with a proliferation of techniques following the introduction of computer and robotic-assisted surgery. Mechanical alignment targets may achieve mechanically-sound alignment while ignoring the soft tissue envelope; kinematic alignment respects the soft tissue envelope while ignoring the mechanical environment. Functional alignment is proposed as a hybrid technique to allow mechanically-sound, soft tissue-friendly alignment targets to be identified and achieved

No Benefit of the Two-incision THA over Mini-posterior THA: A Pilot Study of Strength and Gait

Proponents of the two-incision minimally invasive approach for THA have claimed recovery is dramatically better than after other methods of THA, but this has not been confirmed with any objective data. We designed a prospective randomized trial of the two-incision THA versus the mini-posterior technique to determine whether patients having two-incision THA, when compared with patients having mini-posterior THA, had evidence of less muscle damage as reflected by changes in hip muscle strength after surgery, a less antalgic gait as reflected by changes in the single-leg stance time and walking velocity, and better hip function as reflected by changes in the hip moments during level walking and stair climbing as assessed by comprehensive gait analysis testing. Twenty-one patients, including 13 men and eight women, were prospectively randomized to either the two-incision or the mini-posterior approach and completed preoperative and 6-week postoperative three-dimensional gait analyses and isometric strength testing. We found no evidence that patients who had two-incision THA had less muscle damage, less antalgic gait, or better gait kinematics than patients who had mini-posterior THA. Instead, when there was a difference in strength or gait parameters, it was the patients who had mini-posterior THA who tended to have quicker recovery

Effect of Postoperative Mechanical Axis Alignment on Survival and Functional Outcomes of Modern Total Knee Arthroplasties with Cement: A Concise Follow-up at 20 Years.

Place: United StatesWe previously compared the 15-year survivorship of total knee arthroplasty (TKA) implants that were mechanically aligned (0° ± 3° relative to the mechanical axis) compared with those that were outside that range and considered outliers. The original publication included 398 TKAs (292 in the aligned group and 106 in the outlier group) performed from 1985 to 1990. At the time of follow-up in the previous study, 138 patients (155 TKAs) had died and 59 knees had been revised. Since that publication, 49 additional patients (87 knees) have died. At 20 years, 57 (19.5%) of the 292 knees in the mechanically aligned group had been revised compared with 16 (15.1%) of the 106 knees in the outlier group (p = 0.97). Postoperative alignment within 0° ± 3° of the mechanical axis did not provide a functional advantage at 1, 5, 10, 15, and/or 20 years postoperatively as demonstrated by the Knee Society scores being similar between the groups (p ≥ 0.2 at all intervals). At 20 years, we once again did not find that neutral mechanical alignment provided better implant survivorship than that found in the outlier group. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence

Intraoperative Fracture During Primary Total Knee Arthroplasty

While the occurrence of periprosthetic fractures around total knee arthroplasties (TKAs) is well know, little is known about intraoperative fractures that occur during TKA. We describe the incidence, location, and outcomes of iatrogenic intraoperative fracture during primary TKA. We reviewed 17,389 primary TKAs performed between 1985 and 2005 and identified 66 patients with 67 intraoperative fractures including 49 femur fractures, 18 tibia fractures, and no patella fractures. There were 12 men and 54 women with a mean age of 65.2 ± 16 years. Of the 49 femur fractures, locations included medial condyle (20), lateral condyle (11), supracondylar femur (eight), medial epicondyle (seven), lateral epicondyle (two), and posterior cortex (one). Tibia fractures (18) included lateral plateau (six), anterior cortex (four), medial plateau (three), lateral cortex (three), medial cortex (one), and posterior cortex (one). Twenty-six fractures occurred during exposure and preparation, 22 while trialing, 13 during cementation, and three while inserting the polyethylene spacer. The minimum followup was 0.15 years (mean, 5.1 years; range, 0.15–15.4 years). All fractures healed clinically and radiographically. Knee Society scores and function scores improved from 46.4 and 34.6 to 79.5 and 61, respectively. Fourteen of the 66 (21%) patients were revised at an average of 2.8 years. Intraoperative fracture is an uncommon complication of primary TKA with a prevalence of 0.39%. Intraoperative fracture occurred more commonly in women (80.6%) and in the femur (73.1%). The majority of fractures occurred during exposure and bone preparation and trialing of the components