Patrick Yoon

Gait analysis comparison of cruciate retaining and substituting TKA following PCL sacrifice

The role of the posterior cruciate ligament (PCL) remains controversial in total knee arthroplasty (TKA), with some surgeons who believe in PCL sacrifice and substitution and others who believe in PCL preservation for stability. Manufacturers have developed both cruciate-substituting/posterior stabilized (PS) implants typically used when the ligament is sacrificed and cruciate retaining (CR) implants designed for ligament preservation. However, studies demonstrate excellent clinical results with CR implants despite PCL sacrifice. This study sought to determine functional stability differences between PS and CR TKAs following PCL sacrifice. Eighteen (9 matched pairs) subjects with either a PS or CR TKA and sacrificed PCL and a normal contralateral knee were subjected to physical exam and gait analysis (walking, stair ascent and descent) using a staircase model, passive reflective arrays and an optoelectric system. No differences were detected between the two groups among any of the measured parameters (knee flexion angle, knee flexion moment, knee power absorption, pelvic tilt). PCL sacrifice in a well-balanced cruciate retaining TKA did not result in instability during stair descent based on gait parameters. The decision to use a posterior stabilized design when faced with an incompetent PCL intraoperatively should be based on factors other than anticipated instability.

Component removal in revision total hip arthroplasty.

Component removal is a time-consuming yet necessary step during revision hip surgeries. Because of the diversity of the components and the methods used to secure them, an equal diversity of approaches and tools are necessary for component removal. Careful and detailed preoperative planning is mandatory, the mode of failure must be understood, and detailed imaging should be available to the surgeon. Understanding the basic principles and indications for each of the techniques would optimize outcome. We review the approaches, tools, and techniques for component removal in revision hip procedures in stepwise sequence.

Varus Distal Femoral Osteotomy

The young patient with knee osteoarthritis (OA) presents a challenging treatment dilemma to the orthopedic surgeon. In the varus knee, delay of OA progression has been successfully performed with proximal tibial osteotomy; in the valgus knee, however, varus distal femoral osteotomy (VDFO) has usually had better results. VDFO is indicated in the physiologically young, active patient in whom conservative therapy for symptomatic lateral compartment arthritis in a stable knee without significant flexion deformity has failed. Meticulous preoperative planning is crucial and entails obtaining long-leg standing radiographs to determine the mechanical and anatomic axes. The medial closing wedge technique is the most common method of performing VDFO, although the lateral opening, dome osteotomy, and hemicallotasis techniques have all had their proponents. Proper pin placement is necessary to correctly make the osteotomy and to obtain the desired correction of deformity. The osteotomy is then stabilized with internal fixation, usually a 90° blade plate. Postoperative weight-bearing is generally delayed for 6–8 weeks. Complications can include nonunion, failure of fixation, infection, loss of correction, and acceleration of medial compartment arthritis. With proper selection and careful attention to detail, VDFO can be successful in delaying the need for total knee arthroplasty (TKA), and it has been associated with 71%–83% good/excellent Hospital for Special Surgery scores at 4–8-year follow-up.

Principles of revision total knee arthroplasty

Revision total knee arthroplasty (TKA) is considered by some to be the most difficult procedure in the field of orthopaedic surgery. Good results can be consistently obtained if a meticulous and methodic approach is taken by the provider. Keeping the goals of treatment in mind as well as possible compounding factors specific to each individual case will aid in achieving optimal results. This article presents the schema one should undergo in a revision TKA, from mechanism of failure to preoperative assessment as well as intra-operative technique and a discussion on rehabilitation principles.

Exposure in revision total knee arthroplasty

Several techniques are available for the often difficult problem of surgical exposure in revision total knee arthroplasty. They include soft tissue and bony methods. This article presents an up-to-date review of these various procedures, with an emphasis on technique and outcomes.

Bone reconstruction in revision total knee arthroplasty

There are approximately 20,000-revision total knee arthroplasties (TKA) performed in North America annually. With a growing number of TKAs being performed and the trend toward a longer life expectancy, failure of the primary TKA is inevitable, thus, revision TKAs are going to be performed at an increasing rate for years to come. A major issue in revision TKA is the degree of bone loss that has occurred. In this article the authors discuss the different classification schemes regarding bone loss and their impact on subsequent treatment modalities. A discussion on assessment of bone loss and the multiple techniques, along with indications for each, that can be employed intraoperatively to account for the bone loss will enable the surgeon to undergo the challenge of bone reconstruction in a stepwise fashion. The article provides advantages and disadvantages to each technique as well as a review of the current literature. Bone deficiency from component removal, osteolysis, or gap balancing can prove to be a significant problem in revision TKA. With careful planning, appropriate judgment, and good surgical technique, good results can be achieved.

Management of the Patella in Revision Total Knee Arthroplasty

Abstract Problems with the patellofemoral joint comprise the most common complication in primary and revision total knee arthroplasty (TKA). The difficulties can range from instability and anterior knee pain at one end of spectrum of severity, to fracture and extensor mechanism disruption at the other end. These complications are generally higher in revision TKA due to compromised bone stock and blood supply. Despite the particular challenges posed by the bone-deficient patella, reasonable results can be achieved.