In patients presenting with significant ligamentous instability/insufficiency and/or significant varus/valgus deformity of the knee, reproduction of knee alignment and soft tissue stability continues to be a difficult task to achieve. These complex primary total knee arthroplasty (TKA) candidates generally require TKA systems incorporating increasing levels of constraint due to the soft-tissue and/or bone deficiencies. In addition, achievement of “normal” gap symmetry through physiologic kinematics is challenging due to the complexity of the overall correction. Advancements in TKA design have not fully addressed the negative consequences of the increased forces between the degree of component constraint, the femoral box, and the tibial post. The purpose of this early feasibility study was to introduce the design characteristics of a primary TKA system that incorporates progressive constraint kinematics using a low profile trapezoidal femoral box, and to assess the short-term clinical and radiographic results of this patient cohort. We retrospectively evaluated 22 consecutive, non-selected, complex primary TKA patients with a minimum of 3-years follow-up and varus deformity of > 20 degrees or valgus deformity of >15 degrees. The Progressive Constraint Kinematics® Knee System (PCK, MAXX Orthopedics, Norristown, PA) was used and provides a variable constraint profile, from high constraint in extension to less constraint in flexion through a novel trapezoidal femoral box. We evaluated patient demographics, pre- and post-operative serial radiography, range of motion (ROM), and total Knee Society Score (KSS – total score). General descriptive statistics and paired t-Test to assess the difference between means at p <0.05 level of significance.INTRODUCTION
METHODS
Post-operative infections following end-stage joint salvage reconstruction, tumor resection and megaprosthetic reconstruction is a major problem because of increasing infection rates in this patient cohort. The success of treatment and longevity is limited because current prosthetic composites do not decrease infection rates in these patients. Silver coating is an innovative development in the prevention of post-operative infection. Presented here is the current knowledge of the use of silver for this patient population including;
The current knowledge of the use of silver coated prostheses for infection control, Concerns with ion release and toxicity, Present current published results and USA experience Discuss current regulatory issues both domestically (USA) and worldwide. We report the results of a comprehensive review of the technology of silver coating application to prostheses and the published clinical results of the success of decreasing the incidence of post-operative infection following tumor resection and limb salvage. The current regulatory status of silver use for orthopaedics will also be discussed.INTRODUCTION
METHODS
Evolving payment models create new opportunities for assessment of patient care based on total cost over a defined period of time. These models allow for analyses of economic data that was previously unavailable and well beyond our familiar studies which typically include length of stay, surgical complications, and post-operative clinical and radiographic assessments. In the United States, the new Federal program entitled The total reimbursement for services performed following primary THA for patients insured by Medicare was analyzed for a group of patients at a single institution during the fiscal years of 2013 and 2014. The population included data on 356 patients who had surgery performed by seven surgeons who used the same pre-operative education, OR, PACU, PT, nursing, and case management. A total of 38 “pre-selected” patients underwent THA by an anterior exposure, 219 had surgery performed by a posterior exposure, and 99 had surgery performed by the superior exposure utilizing mechanical surgical navigation (HipXpert System, Surgical Planning Associates, Boston, MA). Reimbursement for all in-patient and out-patient services performed over the initial 90-day period from sugeical admission was compared across surgical techniques. Reimbursement includes the sum of all payments including the hospital, physicians, skilled nursing facilities, home care, out-patient care, and readmission.INTRODUCTION
METHODS
Cup malpositioning remains a common cause of dislocation, wear, osteolysis, and revision. The concept of a “Safe Zone” for acetabular component orientation was introduced more than 35 years ago. The current study assesses CT studies of replaced hips to assess the concept of a safe zone for acetabular orientation. We assessed the orientation of acetabular components revised due to recurrent instability and compared the results to a series of stable hip replacements.BACKGROUND
PURPOSE
Management of metal on metal hip replacements can be accomplished with a simple algorithm including easily available metal ion levels and hip MRI with metal artifact reducing software. After revision serum metal ion levels can be expected to fall rapidly. Metallic ion release may be related to bearing surface wear and thus serves as an indicator of the in-vivo performance of metal on metal articulations. The purpose of this prospective, controlled study was to compare new large head metal on metal hip components with established modular metal on metal and metal on polyethylene and to determine their effects on serum metal levels before and after revision.Summary
Introduction
The purpose of this study was to compare the clinical, radiographic, and DEXA results of
We report the results of a cementless modular revision component which has been used in our hospital since 1993. There were 103 patients, in which the aforementioned cementless femoral revision component was used. Patients were evaluated, using both a modiþed HHS and serial radiographs performed preoperatively, at 2 weeks, 3 months and annually postoperatively. The patients were followed for a minimum of 4 years. Pre-operatively, bony defects were classiþed on radiographs according to the classiþcation of Mallory. Three hips were excluded from the evaluation: 1 was lost to follow-up and 2 were deceased. 100 hips with an average follow-up of 75 months were retrospectively reviewed. Indication for revision was aseptic loosening in 96 cases and infection in 4. Average number of previous hip surgeries in this patient group was 2.3. Average pre-operative hip score was 48,8 compared to an average postoperative hip score of 74,4. Postoperative complications included 2 infections and 2 cases of DVT with occurrence of PE in 1 case, 4 postoperative dislocations, 2 cases with radiographic subsidence of the femoral component and 1 case with sciatic nerve lesion. Intraoperative complications included femoral fractures upon dislocation of the hip or impaction of the new stem in 37 cases. At time of latest review there were no clinical or radiographic signs of component loosening. The incidence of postoperative and intraoperative complications are comparable to the literature. Clinical and radiographic results of the cementless, modular titanium revision component are promising and support its continued use.
