Unicompartmental Knee Arthroplasty (UKA) has been indicated for inactive elderly patients over 60, but for young and active patients less than 60 years old, it has been regarded as a contraindication. The purpose of this study is to evaluate the usefulness of UKA performed on young Asian patients under 60 years of age by analyzing clinical outcomes, complications and survival rate. The subjects were 82 cases, which were followed up for at least 5 years (from 5 to 12 years). Only Oxford phase III® (Biomet Orthopedics, Inc, Warsaw, USA) prosthesis was used for all cases. The clinical evaluation was done by the range of motion, Knee society score (KSS), WOMAC score. The radiographic evaluation was performed on weight bearing long-leg radiographs, AP and lateral view of the knee and skyline view of the patella. The survival rate was estimated by Kaplan-Meier survival analysis.Purpose
Materials and Methods
Despite the excellent clinical success of total knee arthroplasty (TAK), controversy remains concerning whether or not to resurface the patella. This has led to a number of randomized controlled trials. Randomized controlled trials constitute the most reliable source of evidence for the evaluation of the efficacy of a potential intervention. But most of these studies include all degree of osteoarthritis of the patellofemoral joint. So we did this prospective study to compare clinical and radiological outcomes after TKA with or without patellar resurfacing in patients with grade IV osteoarthritis on patellofemoral joint. 123 cases (93 patients) with Kellgren-Lawrence grade IV osteoarthritis on patellofemoral joint were enrolled for this study. At the operating room, they were randomly assigned to undergo patella resurfacing (62 cases) or patella retention (61 cases). Among them, 114 cases that could be followed for more than 2 years were included in this study (resurfacing group; 59 cases, retention group; 55 cases). When patellar retention was performed, osteophytes of the patella were removed and marginal electrocauterization was carried out. Preoperative and postoperative clinical outcomes were evaluated and compared regarding the Hospital for Special Surgery Patellar (HSSP) score (total 100 point; anterior knee pain, functional limitation, tenderness, crepitus, Q-strength). We also compared Hospital for Special Surgery (HSS) and WOMAC scores, and range of motion (ROM). We also compared radiological outcomes at the final follow up, with regards to mechanical axis of the lower limb, patella tilt and patella congruence angle between two groups.Background
Materials and Methods
A large proportion of knee arthroplasty patients are dissatisfied with their replacement. Significant differences exist between preoperative, postoperative and normal kinematics. A better understanding of the inter-relationships between kinematics, shape and prosthesis placement could lead to improved quality of life. Knee kinematics are altered by total knee arthroplasty (TKA) both intentionally and unintentionally. Knowledge of how and why kinematics change may improve patient outcome and satisfaction through improved implant design, implant placement or rehabilitation. Comparing preoperative to postoperative kinematics and shape of the natural and replaced joint will allow an investigation of the inter-relationships between knee shape, prosthesis placement, knee kinematics and quality of life.Summary Statement
Introduction
Knee kinematics are altered by total knee arthroplasty (TKA) both intentionally and unintentionally. Knowledge of how and why kinematics change may improve patient outcome and satisfaction through improved implant design, implant placement or through rehabilitation. In the present study we imaged and compared the 6 degree-of-freedom (DOF) patellofemoral (PF) and tibiofemoral (TF) kinematics of 9 pre-TKA subjects to the kinematics of 15 post-TKA subjects (Zimmer NexGen LPS implants) using a novel sequential-biplanar radiographic protocol that allowed imaging the postoperative patellofemoral joint under weightbearing throughout the range of motion, which has not been done previously to our knowledge. There were clear, statistically significant differences between the pre-TKA and post-TKA kinematics: for the TF joint, the tibia was more posterior and inferior (max 20 mm and 15 mm, respectively) in the post-TKA group compared to the pre-TKA group (p<0.001), and had neutral alignment in the post-TKA group compared to varus alignment (max 9°) in the pre-TKA group (p<0.001). For the PF joint, the patella was shifted more posteriorly and medially, and tilted more medially in the post-TKA group compared to the pre-TKA group (p<0.001). There were no significant differences in PF superior/inferior translation and flexion/extension (p>0.5). Both groups showed differences from normal kinematics, based on the literature. The kinematic differences are likely due to a combination of surgical, implant and patient factors. To investigate this further, we imaged the 9 pre-TKA subjects a minimum one year after their surgery; analysis of these data is in progress. Computed tomography (CT) scans and quality of life surveys were also taken before and after surgery. By comparing the preoperative and postoperative kinematics and shape for the same subjects, and analysing the interrelationships amongst these, we aim to determine if a different implant shape or different component positioning could create more normal kinematics, resulting in a better clinical outcome.
As a result of lateral skin numbness that quite commonly occurs after knee joint operation, injury of the Infrapatellar branch of Saphenous nerve is often underestimated and regarded as a trivial complications. However, there are many complaints and worries from the patients in relation to the injury of this nerve never seems to stop. The authors wanted to report the results of preserving this nerve during the unicompartmental knee arthroplasty for preventing lateral skin numbness. The targets of this study were 100 cases of the unicompartmental knee arthroplasty by a single surgeon. All of the cases were medial compartmental osteoarthritis and in which a minimally invasive technique was used, with the average follow up of two years and eight months (range 24 to 42 months). The results were recorded in terms of classification of the nerve by location, preservation after surgery, sensory changes of the lateral skin flap, and complications. The classification by the location of this nerve was observed as either Mochida Type I with 76 people (76%), Type II with 16 people (16%), and unclassified types with eight people(8%). In Type I, this nerve was saved in 62 cases (82%). However in Type II, it could not be preserved in any cases because of the surgical procedure. The results of our study showed that while most of the nerve (76%) on average had a distance of 9.13mm (range 2 to 19mm) from the medial joint line to the nerve and passed inferiorly. This results allowed us to predict ahead of the location of this nerve and careful incision during the operation can preserve this nerve. The authors discovered that in cases of unicompartmental knee arthroplasty, the nerve can be easily preserved, as 62 people(82%) of type I had this nerve completely preserved. Even if five extra minutes is necessary in order to preserve this nerve, when we think of the patient’s satisfaction it is thought of as a meaningful procedure.
