We use these guidelines if you received a work-related injury and are curious about the effect of “Scheduled Loss of Use (SLU) on your knee and tibia. Then, you could be eligible for a compensation payment determined by the Workers’ Compensation Board’s regulations.
Our SLU report will conclude that you have permanently lost function in the injured body part due to your work-related accident. The determination of impairment is based on New York state Workers’ Compensation guidelines.
Objectives for Determining Knee and Tibia Impairment
Functions of the knee include:
- Body weight support
- Lowering the body toward the ground with knee flexion
- Raising the body with knee extension
- Ambulation
- Rotational abilities allow the body to twist
Permanent Knee and Tibia Impairment Assessment Methods
We evaluate the degree of permanent residual physical deficit when not expecting further healing during maximum medical improvement (MMI). Therefore, we must determine the MMI based on the clinical treatment course outcome, expertise, and other additional treatment options.
In addition, we will consider the contralateral extremity and expected values when assessing the level of permanent residual physical deficit. Typically, one year from the injury or the last surgery is required to determine the time from the injury to MMI.
We must not assess the permanent residual physical deficit severity of the mechanism of injury. Instead, we use the time of MMI, including physical bone, muscle, cartilage, tendon, nerve, blood vessel, or other tissue damage.
Range of Motion of the Knee
Flexion: We measure knee flexion while the patient is seated and the knee fully extends forward. Then, we measure the angle between the femur and fibula axes by bringing the heel back towards the chair. The total knee flexion range of motion is from full extension (0 degrees) to full flexion (140 degrees).
Extension: We measure knee extension while the patient stands and fully extends the knee. Then, we will determine the extension deficit by assessing the angle of loss from zero (normal).
7.4 Calculating Loss of Use of the Knee
We will assess whether special considerations apply when determining the overall schedule loss of the knee. If no special circumstances exist, we use the following chart to evaluate flexion and extension deficits. First, the maximum loss of the use of the elbow must not exceed ankylosis. Then, we adjust the schedule loss of use percentages for the range of motion values.
We use the lower figure if a single motion deficit exists, such as flexion or extension. However, we use the higher figure if both flexion and extension apply.
Table: Knee: Percent Loss of Use of Knee
To determine deficits, we use the following chart to select a deficit. First, the maximum loss of the use of the knee must not exceed ankylosis (70%). Then, we proportionally adjust the schedule loss of use percentages for the range of motion values.
Special Considerations for the Knee
We utilize the special considerations when evaluating enumerated schedule loss of use values or without a provided schedule value. The maximum schedule loss of use value must not exceed the ankylosis value (70%).
- Patella: We use a 15% loss of use of the leg for total patellar excision and a 10% loss for partial excision and add mobility deficits or muscle atrophy.
- We utilize a 71⁄2 – 10% leg use loss for patellar fracture with internal fixation.
- We evaluate a 10-15% leg use loss for recurrent patellar dislocation, surgical or non-surgical, based on the extent of residual impairment.
- We use a 71⁄2 – 10% leg use loss for mild to marked degree chondromalacia patella depending on motion deficit and muscle atrophy.
- We utilize 0 – 71⁄2 % loss of use of the leg for prepatellar or infrapatellar bursitis.
- We use a 10 – 15% loss of use of the leg when evaluating quadriceps tendon and patellar ligament rupture.
- We evaluate a 10-15% loss of leg use for a tibial plateau fracture.
- We utilize a 71⁄2 – 10% loss for osteochondritis desiccants, surgical or non-surgical, based on the extent of residual impairment.
- We do not schedule knee instability unless with reconstructive surgery. However, we will consider classification if surgery fails and with persistent instability, requiring a brace. In addition, we will evaluate a schedule loss of use of the leg for ligament laxity (anteroposterior or lateral medial).
- We will consider classification for a non-functional prosthesis amputation with residual symptoms and complications, including neuroma, phantom pain, and chronic ulcers.
- We evaluate a classification for recurrent knee locking that is not amenable to schedule.
- We use a 0-10% loss of use of the leg for a healed and without malalignment tibial shaft fracture.
- Total or partial knee arthroplasty or replacement: We aim to restore joint function and assess at least twelve months post-operative as clinical function changes may occur. Then, schedule according to:
- We measure the greater impairment degree for flexion and extension ROM.
- Position:
- alignment: varus or valgus deformity
- stability: medial/lateral (ML) laxity
- anterioposterior (AP) motion
- leg length (LL)
- alignment: varus or valgus deformity
- We measure atrophy at mid-thigh and compare it to the contralateral extremity.
- We will consider chronic complications, according to the following table, unless using a classification.
- We measure the greater impairment degree for flexion and extension ROM.
We use the following chart to determine the schedule loss of use values. An ideal outcome (Row A) is a 35% schedule loss of use. Then, we will add the value for other deficits to values that closely match the provided deficit in each column when deficits exceed those listed in Row A to the base value of 35% to calculate the total schedule loss of use award value.
Table: Full or Partial Knee Replacement: Schedule Loss of Use
Example:
A patient underwent corrective knee replacement surgery. We determined during MMI that the patient will heal with a poor outcome, minimal flexion range of motion, limited at 30 degrees, and malalignment at 15 degrees.
- Begin the value of the replacement at 35%.
- Add a 30% loss for high flexion deficit (30 degrees).
- Add a 5% loss for malalignment (15 degrees).
- The overall value is 70%.
Knee Amputation
We use a 100% loss of leg use for an amputation at the knee; utilize a 95% loss for a below-the-knee amputation (six inches below the knee; 90% loss at mid-calf amputation. Then, we will allow an additional schedule award for an amputee with subsequent injury and 100% leg use loss.
Please refer to your state’s Workers’ Compensation Board website or speak with your Workers’ Compensation attorney for more information.