THE LOWER EXTREMITIES AMA G UIDES CHAPTER 17

1 6/14/20161 THELOWEREXTREMITIESAMA GUIDESCHAPTER17 Tim MussackMarlene PhillipsBradford & Barthel, LLPAMA Analysis and Ratings DivisionBradford & BarthelAMA Analysis and Ratings Division Tim Mussack(916) Marlene Phillips(909) Frequently Used Chapters Chapters 1 & 2 --- The Constitution From page 17, in the Introduction to CHAPTER 2, the Practical Application of the Guides: Two physicians, following the methods of the Guides to evaluate the same patient, should report similar results and reach similar conclusions. Moreover, if the clinical findings are fully described, any knowledgeable observer may check the findings with the Guides criteria. The Almaraz Guzman en banc decision of 9/3/2009: ..by requiring use of the AMA Guides to determine impairment, the Legislature furthered its expressly stated goal of achieving consistency, uniformity, and objectivity.

2 CHAPTER 15 --- Spine CHAPTER 16 --- Upper Extremity (UE) CHAPTER 17 --- LOWER Extremity (LE) LOWER EXTREMITIES LOWER extremity impairment values Combining Impairment PD (after adjustment) Methods of 17 The LOWER Extremitiesthere are errata Principles of Assessment(p. 524-525) Methods of Assessment (p. 525-554) LE Impairment Evaluation Procedure Summary and Examples (p. 555-560) Impairment evaluations are performed after the injured worker attains Regional Impairment AMA Guides is not jurisdictionally specific for evaluating Permanent Disability The California Schedule for Rating gives additional instructions for rating Permanent Disabilities. Section 1 of the rating schedule is Introduction and page 1-4: "The impairment number identifies the body part, organ system and/ or nature of the " "Under Section 2 of the Permanent Disability Rating Schedule, an appropriate impairment number can be found for most impairments.

3 "On page 1-5: "A single injury can result in multiple impairments of several parts of the body. For example, an injury to the arm could result in limited elbow range of motion and shoulder "On page 1-11 of the Schedule: "..'adjusting' refers to adjusting an AMA impairment rating for diminished future earning capacity, occupation, and age." "Impairments of an individual extremity are adjusted and combined at the whole person level with other impairments of the same "86/14/20165 Impairment Values 100% LE = 40% WPI [LE % x .4 = WPI %] Table 17-3 page 527 100% Foot = 70% LE [Foot % x .7 = LE %] 17-3 page 527 Conversion Table LE to or Add, and CVC Numbers that are put together for evaluation of impairment/ PD must be either added or combined. When to combine: COMBINE for most situations -- unless specific instructions state to ADD impairment values.

4 The effect/ purpose of combining is that it prevents the combined value from exceeding + B(1 A) [where A and B are decimal equivalents] When to add: The most notable exception to combining impairments is with the evaluation of range of motion impairment for the same part of the body (for example, right ankle motion) [hand evaluation has unique methodology] or Add, and CVC How to combine: Page 1-11 of the 2005 PDRS: Multiple impairments such as those involving a single part of an extremity, two impairment involving a shoulder such as shoulder instability and limited range of motion, are combined at the upper extremity level, then converted to whole person impairment and adjusted before being combined with other parts of the same extremity. Impairments with disability numbers in the and series are converted to whole person impairment and adjusted before being combined with any other impairment of the same extremity.

5 Impairments of an individual extremity are adjusted and combined at the whole person [PD] level with other impairments of the same extremity before being combined with impairments of other body parts. For example, an impairment of the left knee and ankle would be combined before further combination with an impairment of the opposing leg or the 17 13 Methods of Used to Evaluate Impairments of the LOWER 17-2, page 526 After all potentially impairing conditions have been identified and correct ratings recorded ..select (s) and record the estimated impairment for each. explain in writing why a particular method(s)..was chosen. (p. 526) 17-2 Typically, one method will adequately characterize the Avoid combining methods that rate the same condition. If more than one method can be used, the method that provides the higher rating should be adopted.

6 (page 527) When a Table gives a range for objective findings, and a correlating range for impairment, use interpolation to provide the appropriate value (as shown in Example 17-15, with leg shortening) #1 Limb Length Discrepancy X-rays strongly recommendedRepeat 3 times3 averaged to reduce measurement error P. 5286/14 17-4 (p. 528)Impairment Due to Limb due to: Overriding, Malalignment, or Fracture cm (0-1/2 in.) = 5% cm (1/2-1 in.) = 10% cm (1-1 in.) = 15% cm (1 - 2 in.) = 20% LE other functional (p 528)6/14 #2 Gait Derangement Why is it being used? Should use more specific method Correlating objective findings Read Table 17-5 (p. 529) carefully No 17-5, p. 529 6/14 Except as otherwise 17-5 [is] for full-time gait derangements of persons who are dependent on assistive devices. Not for abnormalities based only on subjective factors, such as pain or sudden giving-way, as individual with low-back discomfort who chooses to use a cane to assist in walking.

7 Whenever possible, the evaluator should use a more specific method. When the gait method is used, a written rationale should be included in the report. The LOWER limb impairment percents shown in Table 17-5 stand alone and are not combined with any other impairment evaluation method. As also expressed in the Comment section for Example 17-1 on page 528 of the AMA Guides, Although the individual has a limp (gait abnormality), gait derangement should be used only when no other method is available to rate the person. 6/14 #3 Muscle Atrophy (Unilateral) At thigh 10 cm above patella Calf at max level Must compare measurement to opposite, uninjured LE Combine thigh and calf Measurements Compare measurement to opposite member Difference in circumference might be: Swelling Varicose veins Opposite member injured6/14 17-6 (p.)

8 530)Impairment Due to Unilateral Leg Muscle Right tibia fracture MMI Pain free walking Right thigh atrophy = 2 cm Right calf atrophy = 1 cm6/14 = 2 cm = 8% LE = 3% WPICalf = 1 cm = 3% LE = 1% WPIC ombine: 8% C 3% = 11 LEConvert: 11% LE = 4% #4 Manual Muscle Testing Use Table 17-7 &17-8 (pages 531- 532) Note typo - Hip abduction, Grade 3 = 37% LE6/14 17-7 (p. 531)Criteria for Grades of Muscle Function of the LOWER Muscle Testing (cont d)Cautions page 531: depends on the examinee s cooperation should be concordant with and medical evidence More than one grade between examiners More than one grade from exam to exam Pain Fear of pain Attributed to deficit of a peripheral nerve 6/14 17-8, p. 532 Combine Example of Motion(pages 533-538)Method #56/14 Use ROM only If it is [ROM] has an organic Obtain 3 measurements; use greatest Add ROM impairments in 17-1 (p.

9 534)Using a Goniometer to Measure Flexion of the Right Hip6/14 17-2 (p. 534)Neutral Position, Abduction, Adduction of the Right 17-3 (p. 535)Measuring Internal and External Hip Rotation6/14 17- 4 (p. 535)Measuring Knee 17-5 (p. 535)6/14 of Motion (page 537) Table 17-9 - Hip Table 17-10 - Knee Table 17-11 - Ankle Table 17-12 - Hindfoot Table 17-13 - Ankle/Hindfoot Table 17-14 - Toes (see footnote) :Ankle flexion of 6 = ?= 6% WPI (15% LE) (Table 17-11, p. 537)Ankle extension of 5 = ?= 3% WPI (7% LE) (Table 17-11)1 cm calf atrophy?= 1% WPI (Table 17-6, p. 530) Add flexion + extension =15% LE + 7% LE = 22% LE = 9% WPIDo not use atrophy (1% WPI)R: 1) Table 17-2 prohibits combining2) ROM is more generous6/14 of Motion (continued)Invalid if: Class inconsistency between 2 observers Class inconsistency between exams Pain Fear of #6 Ankylosis (joint immobility)See text for optimal position valuesHip = 50% LE = 20% WPI (p.

10 538)Knee = 67% LE = 27% WPI (p. 540)Ankle = 14% Foot = 10% LE = 4% WPI (p. 541)Foot = 14% Foot = 10% LE = 4% WPI (p. 542)Toes see Table 17-30 (page 543)6/14 (continued)1. Determine value for optimal position (text)2. Use Tables (pages 538-543) for deviation values (malposition increases impairment)3. Add multiple malpositions for same joint4. Combine ankylosis of different joints5. The baseline rating for ankylosis in a neutral position is used only once for each joint. PartMotionTablePagehipinternal rot17-16539hipext rot17-17539hipabd17-18539hipadd17-19539k neevarus17-20540kneevalgus17-21540kneefl ex17-22540kneeint or ext 17-23540malrotation6/14 PartMotionTablePageankleplantar flex or dorsiflexion17-24541anklevarus17-25541an klevalgus17-26541ankleint malrotation17-27541ankleext malrotation17-28541ankletibia-os calcis #7 Arthritis6/14 (cont d) Use x-rays ( standing if possible ) with Table 17-31 (page 544) ( ) = normal cartilage intervals Compare uninjured opposite 17-31, p.