Mechanical Strength of the Proximal Tibia Following Total Knee Arthroplasty: A Cadaveric Study of Resection Depth and Bone Density.

Background: Tibial component failure has been a problem in total knee arthroplasty, it is still undetermined how tibial resection depth affects the strength to support a tibial component. This study examined the relationship between the resection depth and the bone density and the mechanical strength to support the tibial component.

Materials And Methods: Eight matched pairs of fresh, frozen cadaver lower legs were imaged with computed tomography to assess the bone density.

Seasonal variation in adult hip disease secondary to osteoarthritis and developmental dysplasia of the hip.

Aim: To determine if there was a seasonal variation in adults undergoing total hip arthroplasty for end stage hip disease due to osteoarthritis (OA) or sequelae of developmental dysplasia of the hip (DDH).

Methods: The total hip registry from the author's institution for the years 1969 to 2013 was reviewed. The month of birth, age, gender, and ethnicity was recorded.

ACL Damage and Deficiency is Associated with More Severe Preoperative Deformity, Lower Range of Motion at the Time of TKA.

Background: ACL status varies in the arthritic knee during TKA.

Questions/purposes: The purpose of this study was to examine clinical features and intraoperative findings associated with stages of ACL degeneration.

Methods: Coronal deformity, ROM, intra-articular degenerative patterns, and ligament releases were assessed for 1656 knees during TKA.

Twenty-Five-Years and Greater, Results After Nonmodular Cemented Total Knee Arthroplasty.

Background: Total knee arthroplasty (TKA) has been shown to be very successful with long-term follow-ups. But there are no reports showing prosthesis survival at 25-30 years. Here, we report the outcomes for 25-30 years using the Anatomic Graduated Component (Biomet, Warsaw, IN) TKA and elucidate the etiology and cause of failure of the components.

Midterm Results of the Vanguard SSK Revision Total Knee Arthroplasty System.

Revision total knee arthroplasty (TKA) is becoming increasingly common as the population ages and the number of existing primary TKAs continues to increase. Revision TKA systems use a greater range of component modularity than primary TKA systems, including stems, augments, and varying levels of constraint. The purpose of this study was to retrospectively review the authors' institution's use of one specific revision knee implant system and its midterm results.

Short-term Outcomes With a Second-Generation Uncemented Stem in Total Hip Arthroplasty.

An uncemented stem has been used successfully in total hip arthroplasty for 2 decades, and some implants have been updated. The authors have used second-generation uncemented proximal porous coating stems, the Echo Bi-Metric Full Proximal Profile stem (Echo FPP; Biomet, Warsaw, Indiana) and the Echo Reduced Proximal Profile stem (Echo RPP; Biomet). This article reports short-term outcomes with these stems compared with their predecessor, the Bi-Metric stem (Biomet).

A Finite-Element Study of Metal Backing and Tibial Resection Depth in a Composite Tibia Following Total Knee Arthroplasty.

Prosthetic alignment, patient characteristics, and implant design are all factors in long-term survival of total knee arthroplasty (TKA), yet the level at which each of these factors contribute to implant loosening has not been fully described. Prior clinical and biomechanical studies have indicated tibial overload as a cause of early TKA revision. The purpose of this study was to determine the relationship between tibial component design and bone resection on tibial loading.

Cemented and uncemented total hip arthroplasty using the same femoral component.

Purpose: The purpose of this study was to evaluate the same femoral component after cemented and uncemented total hip arthroplasty. The results were compared in terms of hip scores, subsidence, and survivorship.

Methods: Between 1986 and 1996, 1017 primary THAs were implanted in 882 patients using the same porous-coated, titanium-alloy, femoral component.

Cultural Nuance in Orthopedic Foreign Aid: Differences in Patient Concerns.

Orthopedic aid to developing nations is expanding and becoming a unique facet of the specialty. This investigation seeks to compare patient impressions and concerns regarding the care patients receive as part of an itinerant surgical aid trip in 2 nations. In 2013 and 2014, patients from 2 separate nations completed a Likert scale survey assessing impressions of the care they received at the hands of a surgical team from abroad.

Ten-Year Outcome Comparison of the Anatomical Graduated Component and Vanguard Total Knee Arthroplasty Systems.

Unlabelled: The development of a new total knee system as a successor prosthesis in total knee arthroplasty (TKA) requires clinical outcome improvement. 10,843 TKAs were performed of which 9169 utilized the Anatomical Graduated Component (AGC) and 1674 utilized the Vanguard prosthesis (both Biomet, Warsaw, IN). Survival rates at ten years postoperatively for the AGC and Vanguard were 98.

Use of screws and cement in revision TKA with primary or revision specific prosthesis with up to 17 years followup.

The purpose of this study was to investigate the use for screws and cement, and primary and revision specific prosthesis for revision TKA. Between July 1989 and February 2010, 839 consecutive revision TKAs were performed, with 609 knees meeting inclusion criteria. At 17 years followup, Kaplan-Meier survivorship was 0.

The Surgeon's Role in Relative Success of PCL-Retaining and PCL-Substituting Total Knee Arthroplasty.

Background: The orthopedic literature has not shown a universal and replicated difference, outside of flexion, in clinical results between posterior cruciate ligament retention and posterior cruciate ligament substitution in total knee arthroplasty.

Questions/purposes: This study was performed to compare the restoration of flexion and knee function in a large series of cruciate-retaining and cruciate-substituting total knee arthroplasties (TKRs). In addition, we aimed to study how other variables, such as those unique to each surgeon, may have affected the results.

Twenty-year followup of an uncemented stem in primary THA.

Background: Uncemented stems have been used in THA for well over two decades, but there are relatively few studies reporting on the results after 20 years.

Questions/purposes: The purpose of this study was to evaluate at a minimum followup of 20 years (1) hip scores; (2) radiographic findings, including stem fixation and osteolysis; (3) reoperations; and (4) survivorship free from aseptic loosening in a group of patients who underwent primary THA using a proximally porous-coated, plasma-sprayed, straight-stemmed, titanium-alloy femoral component.

Methods: Between 1987 and 1993, we performed 1517 primary THAs, of which 447 were cementless, and 157 used the implant under study here (representing 10% of the THAs during the period in question).

Use of screws and cement in primary TKA with up to 20 years follow-up.

The purpose of this study was to investigate screws and cement for large tibial bone defects during primary TKA. Of 14,686 consecutive primary TKAs performed between December 1988 and February 2010, 256 received screws and cement for tibial defects. Cox regression was used for the analysis.

The effect of rotating platform TKA on strain distribution and torque transmission on the proximal tibia.

Limited experimental data exist comparing the mechanical response of the tibial cortex between fixed and rotating platform (RP) total knee arthroplasty (TKA), particularly in the revision setting. We asked if RP-TKA significantly affects tibiofemoral torque and cortical stain response in both the primary and revision settings. Fixed and RP tibial trays were implanted into analogue tibias and biomechanically tested under axial and torsional loading.

Concerns of an itinerant surgeon: results of a Guatemalan surgical aid trip.

Over the past decade the popularity of foreign medical aid has increased and gained notoriety. Operation Walk is a philanthropic organization dedicated to improving the ambulatory potential of patients in developing countries by providing free surgical treatment for patients who otherwise lack access to care of debilitating bone and joint conditions. During Operation Walk Mooresville's 2013 trip to Guatemala 40 patients prospectively completed a Likert Scale style survey.

Why are total knees failing today? Etiology of total knee revision in 2010 and 2011.

Revision knee data from six joint arthroplasty centers were compiled for 2010 and 2011 to determine mechanism of failure and time to failure. Aseptic loosening was the predominant mechanism of failure (31.2%), followed by instability (18.

Tibial loading after UKA: evaluation of tibial slope, resection depth, medial shift and component rotation.

With increased precision in alignment offered by new generations of instrumentation and customized guides, this study was designed to establish a biomechanically-based target alignment for the balance of tibial loading in order to diminish the likelihood of pain and subsidence related to mechanical overload post-UKA. Sixty composite tibias were implanted with Oxford UKA tibial components with varied sagittal slope, resection depth, rotation and medial shift using patient matched instrumentation. Digital image correlation and strain gage analysis was conducted in static loading to evaluate strain distribution as a result of component alignment.

Preoperative malalignment increases risk of failure after total knee arthroplasty.

Background: Implant survival after total knee arthroplasty has historically been dependent on postoperative knee alignment, although failure may occur when alignment is correct. Preoperative knee alignment has not been thoroughly evaluated as a possible risk factor for implant failure after arthroplasty. The purpose of this study was to analyze the effect of preoperative knee alignment on implant survival after total knee arthroplasty.

High initial stability in porous titanium acetabular cups: a biomechanical study.

Initial stability with limited micromotion in uncemented total hip arthroplasty acetabular components is essential for bony attachment and long-term biomechanical fixation. This study compared porous titanium fixation surfaces to clinically established, plasma-sprayed designs in terms of interface stability and required seating force. Porous plasma-sprayed modular and metal-on-metal (MOM) cups were compared to a modular, porous titanium designs.

Acetabular cup design influences deformational response in total hip arthroplasty.

Background: Press-fit acetabular components are susceptible to deformation in an underreamed socket, with excessive deformation of metal-on-metal (MOM) components potentially leading to increased torsional friction and micromotion. Specifically, however, it remains unclear how cup diameter, design, and time from implantation affect shell deformation.

Questions/purposes: We asked whether (1) changes in component geometry and material altered maximum shell deformation and (2) time-dependent deformational relaxation processes occurred.

Acetabular cup stiffness and implant orientation change acetabular loading patterns.

Acetabular cup orientation has been shown to influence dislocation, impingement, edge loading, contact stress, and polyethylene wear in total hip arthroplasty. Acetabular implant stiffness has been suggested as a factor in pelvic stress shielding and osseous integration. This study was designed to examine the combined effects of acetabular cup orientation and stiffness and on pelvic osseous loading.

Heterotopic bone formation following resurfacing total hip arthroplasty.

Heterotopic bone (HO), a rare association with total hip arthroplasty (THA), has recently been shown to be more of a problem with resurfacing hip arthroplasty (RHA). It has been speculated to be the result of greater soft tissue dissection required for this procedure. HO most commonly develops in males and patients with bilateral disease.

Pain relief and functional improvement remain 20 years after knee arthroplasty.

Background: TKA provides demonstrable pain relief and improved health-related quality of life. Yet, a decline in physical function may occur over the long term despite the absence of implant-related problems.

Questions/purposes: (1) Does pain relief diminish over 20 years after TKA? (2) Does function decline over 20 years in terms of Knee Society function, knee, and walking scores? And (3) what is the patient-reported activity level at most recent followup?

Patients And Methods: We retrospectively identified 1471 patients with 1757 primary cruciate-retaining TKAs implanted between 1975 and 1989 and identified 128 living patients (8.