The goal of this interventional pilot study is to evaluate if performing ligament balancing on the medial collateral ligament (MCL) in a more systematical manner with a novel instrument can produce more objective and repeatable ligament lengthening in Total Knee Arthroplasty. The main questions it aim to answer are: 1. Is it feasible to perform systematic ligament balancing on the MCL using a novel instrument? 2. Can a novel instrument for ligament balancing acquire more objective and repeatable results, without risk of injury? Participants must consent prior to the surgery, but inclusion is only done once ligament balancing is indicated during surgery. Patients will be follow-up as standard protocol for Total Knee Arthroplasty patients at the hospital.
Varus deformity is the most common deformity (60-80%) in patients undergoing total knee arthroplasty (TKA). In varus knees, there could be shortening of medial structures; therefore, if mechanical alignment is the goal, perpendicular bone cuts could produce a trapezoidal gap between the femur and tibia, with a shorter medial side. This imbalance should be corrected through ligament balancing as it is seen as a prerequisite for good function and survival. Aunan et al. found ligament balancing to be necessary in 70 of 100 consecutive TKAs. Several ligament balancing techniques exist and most focus on lengthening the soft tissue on the concave side of the knee. Bellemans' and Whiteside's techniques are examples of ligament balancing procedures. In varus knees Bellemans' technique is performed with multiple perforations (pie-crusting) of the medial collateral ligament (MCL), while Whiteside's technique is performed with sequential ligament and soft tissue release, where the MCL is evaluated first. However, no technique has proved clinically superior to others. In traditional methods, it is difficult to reliably predict ligament lengthening and it relies on the performing surgeons' feel and experience. Aunan et al. found wide variation in lengthening achieved using Whiteside's technique. Therefore, the investigators have developed a novel device, which aspires to further develop Bellemans' technique and produce repeatable soft tissue lengthening of the MCL. In varus knees the most important structure in ligament balancing is the superficial and deep MCL (hereafter MCL). Bellemans' technique is a proven technique, which uses an end-cutting cannula to puncture the MCL by freehand, with the objective of severing some ligament fibers. When the force applied to the ligament is kept constant, each remaining fiber will be exposed to a higher force and lengthen. Bellemans' technique lacks an objective method of guiding the puncturing, and the execution and results therefore vary. The novel instrument invented by the investigators, has a specific grid that objectively guides perpendicular puncturing using an end-cutting cannula and evenly distributes punctures throughout the ligament, which will produce a predefined spread of punctures and severing of fibers. The investigators believe this grid is key to achieving repeatable lengthening of the MCL, and promising results have been shown in porcine and human cadaveric tissue.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
40
Patients will be evaluated perioperatively for ligament balance. When indicated, the novel instrument will guide puncturing of the medial collateral ligament in a systematic and step-wise fashion. Achieved ligament balance will be observed and controlled by computer navigation and a ligament tensor. Performed at Bærum Hospital vestre Viken Hospital Trust.
Patients will be evaluated perioperatively for ligament balance. When indicated, the novel instrument will guide puncturing of the medial collateral ligament in a systematic and step-wise fashion. Achieved ligament balance will be observed and controlled by conventional methods using spatulas.
Bærum Hospital, Vestre Viken Hospital Trust
Bærums verk, Akershus, Norway
COMPLETEDOslo University Hospital, Ullevaal
Oslo, Oslo County, Norway
RECRUITINGIs it feasible to perform systematic ligament balancing on the MCL using a novel instrument?
The investigators will be studying if it is possible to perform systematic ligament balancing on the MCL during total knee arthroplasty surgery, using a novel instrument.
Time frame: 1 year
MCL-lengthening in millimeters after ligament balancing using the novel instrument
The investigators will be evaluating the amount of lengthening of the medial collateral ligament (MCL) in millimeters, that is achieved when using a novel instrument for systematic ligament balancing in total knee arthroplasty. Lengthening in millimeters is evaluated using computer navigated orthopaedic surgery (CAOS) and ligament tensioners or spatulas. The investigators will evaluate if the lengthening is linear and repeatable between individuals using regression analysis.
Time frame: 1 year
Demographic information - height (cm) - and how this parameters affects ligament balancing.
The investigators will evaluate if height in centimeters plays a role in how much ligament lengthening is achieved when using a novel instrument for systematic ligament balancing in MCL-lengthening. Evaluations will be done using regression analysis.
Time frame: 1 year
Demographic information - weight (kg) - and how this parameters affects ligament balancing.
The investigators will evaluate if weight in kilograms plays a role in how much ligament lengthening is achieved when using a novel instrument for systematic ligament balancing in MCL-lengthening. Evaluations will be done using regression analysis.
Time frame: 1 year
Demographic information - age (years) - and how this parameters affects ligament balancing.
The investigators will evaluate if age in years plays a role in how much ligament lengthening is achieved when using a novel instrument for systematic ligament balancing in MCL-lengthening. Evaluations will be done using regression analysis.
Time frame: 1 year
Demographic information - sex (biologic, male/ female) - and how this parameters affects ligament balancing.
The investigators will evaluate if biological sex, defined as male or female, plays a role in how much ligament lengthening is achieved when using a novel instrument for systematic ligament balancing in MCL-lengthening. Evaluations will be done using regression analysis.
Time frame: 1 year
Demographic information - co-morbidities (disease state) - and how this parameters affect ligament balancing.
The investigators will evaluate if co-morbidities, defined as disease states (eg. heart-failure, chronic lung disease, rheumatoid arthritis, etc) plays a role in how much ligament lengthening is achieved when using a novel instrument for systematic ligament balancing in MCL-lengthening. Evaluations will be done using regression analysis.
Time frame: 1 year
Patient reported outcome measures (PROM) using EQ-5D-5L
Standard protocol after total knee arthroplasty surgery at Baerum Hospital will be followed. It is standard practice to evaluate the patient health using self-assessement questionnaires at approximately 6 months. One of these questionnaires is called: EQ-5D-5L or EuroQol-5 dimension-5 Level questionnaire. It consists of 5 equally weighted dimensions with 5 equally weighted levels. The five dimensions that the questionnaire evaluates is divided into five levels of perceived problems (1-5). 1 indicates no problems and 5 indicates extreme problems. A higher level indicates more problems. The levels are combined in a 5-digit state. The minimum value is 11111 and the maximum values 55555. The combination of levels in the state indicates the severity of problems for the patient.
Time frame: 1 year
Patient reported outcome measures (PROM) using FJS-12
Standard protocol after total knee arthroplasty surgery at Baerum Hospital will be followed. It is standard practice to evaluate the patients health using self-assessement questionnaires at approximately 6 months. One of these questionnaires is called: FJS-12 or Forgotten Joint Score 12 questions, is is designed to be used to asses artificial prosthesis awareness during daily activities following arthroplasty. The version for the knee will be used. It consists of 12 equally weighted questions that are answered on a five-level Likert scale from "never" to "mostly". Answers to each question are individually scored and summed to create a score (0-100). A low score indicates that the patient is very aware of their artificial joint and a high score indicates that the patients are very satisfied because the joint does not feel artificial.
Time frame: 1 year
Patient reported outcome measures (PROM) using KOOS
Standard protocol for Bærum Hospital and the Norwegian Registry after total knee arthroplasty surgery will be followed.One of these questionnaires is called: KOOS. KOOS is the of the most used PROMs for evaluation conditions surrounding total knee arthroplasty. KOOS-12 contains 12 items (questions). Each question is scored from 0-4, with 0 indicating no problems and 4 extreme problem. However, an overall impact score is calculated (0-100) using the 12 questions, where 0 indicates the most problematic knee and 100 the best outcome.
Time frame: 1 year
Coronal plane angles
The investigators will be evaluating the amount of lengthening of the medial collateral ligament (MCL) in millimeters, that is achieved when using a novel instrument for systematic ligament balancing in total knee arthroplasty. Lengthening in millimeters is evaluated using computer navigated orthopaedic surgery (CAOS) and ligament tensioners or spatulas. The investigators will evaluate if the lengthening is linear and repeatable between individuals using regression analysis.
Time frame: 1 year
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