Disclosures. Breaking the Law of Valgus. Law of Valgus. Law of Valgus. MRI Studies of OA. Objectives 11/7/2011

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1 11/7/211 Breaking the Law of Valgus the surprising and unexplained prevalence of medial patellofemoral cartilage damage None Disclosures Doug Gross Josh Stefanik Frank Roemer Michael Nevitt ora Lewis Jingbo Niu li Guermazi Leena Sharma Neil Segal David Felson Law of Valgus Valgus Q-angle results in lateral force on patella FS involves lateral loading and lateral cartilage damage F O has similar etiology and location Med F O occurs only rarely and is due to varus malalignment Ficat and Hungerford. Disorders of the atellofemoral Joint Many interventions assume lateral F disease ttempt to realign patella medially May not be indicated for medial F disease Law of Valgus ly realign patella MRI Studies of O Objectives Smaller x-ray studies 1 assessed med vs. lat F O by comparing joint space width 2 Larger MRI studies permit direct determination of med vs. lat F cartilage damage prevalence 1 Iwano et al, iccutini et al, 24 Determine prevalence of med vs. lat F cartilage damage in 3 large MRI studies of knee O Relation to varus, neutral, valgus alignment 1

2 11/7/211 3 MRI Studies 1. Boston O of the Knee Study () Boston V med center > 1 knee with clinical O Baseline MRI (1.5T) More sx knee Full-limb x-ray 3 MRI Studies 2. Framingham O Study () Offspring and ommunity cohorts 5-8 yrs Unselected for knee sx Baseline MRI (1.5T) R knee in community Sx knee in offspring Full-limb x-ray Subsample 3 MRI Studies F artilage Damage 3. Multicenter O Study () labama and Iowa cohorts 5-8 yrs >1 knee with or at risk of O Baseline MRI (1.T) Full-limb x-ray Whole Organ MR Scoring (WORMS) Same 2 radiologists, identical protocol (weighted kappa.73-.8) WORMS > 2, > 3, > 4, > 5 damage considered Normal thickness reas of damage Diffuse damage 4 5 Focal damage Extensive fullthickness 2.5 full-thickness focal damage No cartilage remaining 6 eterfy et al, 24 F artilage Damage Whole Organ MR Scoring (WORMS) Same 2 radiologists, identical protocol (weighted kappa.73-.8) WORMS > 2 = damage F artilage Damage Whole Organ MR Scoring (WORMS) Same 2 radiologists, identical protocol (weighted kappa.73-.8) WORMS > 5 = damage 1 Normal thickness Diffuse damage 4 1 Normal thickness Diffuse damage reas of damage 5 Focal damage Extensive fullthickness 2.5 full-thickness focal damage No cartilage remaining 6 WORMS = Focal damage Extensive fullthickness 2.5 full-thickness focal damage reas of damage No cartilage remaining 6 WORMS = 5 2

3 11/7/211 F Damage F Damage F F F Damage = 1. Med patella damaged 2. Med patella OR med trochlea damaged F Damage F Damage F F F Damage = 1. Med patella damaged Med patella OR med trochlea damaged F Damage F Damage F F F Damage = 1. Lat patella damaged 2. Lat patella OR lat trochlea damaged F Damage = 1. Med patella damaged Lat patella OR lat trochlea damaged 3

4 11/7/211 Knee lignment Same protocol in all 3 studies Full-limb standing x-ray HK angle (I ) 1. Varus (< -2º) 2. Neutral (-2º to 2º) 3. Valgus (> 2º) Mechanical lignment (HK angle) Study opulation 224 subjects 224 knees 35 subjects 428 knees 1381 subjects 1621 knees ge, mean (SD) 66.7 (9.4) 65. (8.9) 62.1 (8.) BMI, mean (SD) 3.7 (4.8) 29.2 (5.5) 3. (4.9) Female, % Knee ain, % X-ray F O, % lignment, N (%) Varus 14 (62.5) 359 (83.9) 777 (47.9) Neutral 48 (21.4) 49 (11.5) 532 (32.8) Valgus 36 (16.1) 2 (4.7) 312 (19.3) Study opulation 224 subjects 224 knees 35 subjects 428 knees 1381 subjects 1621 knees ge, mean (SD) 66.7 (9.4) 65. (8.9) 62.1 (8.) BMI, mean (SD) 3.7 (4.8) 29.2 (5.5) 3. (4.9) Female, % Knee ain, % X-ray F O, % lignment, N (%) Varus 14 (62.5) 359 (83.9) 777 (47.9) Neutral 48 (21.4) 49 (11.5) 532 (32.8) Valgus 36 (16.1) 2 (4.7) 312 (19.3) Study opulation 224 subjects 224 knees 35 subjects 428 knees 1381 subjects 1621 knees ge, mean (SD) 66.7 (9.4) 65. (8.9) 62.1 (8.) BMI, mean (SD) 3.7 (4.8) 29.2 (5.5) 3. (4.9) Female, % Knee ain, % X-ray F O, % lignment, N (%) Varus 14 (62.5) 359 (83.9) 777 (47.9) Neutral 48 (21.4) 49 (11.5) 532 (32.8) Valgus 36 (16.1) 2 (4.7) 312 (19.3) Study opulation 224 subjects 224 knees 35 subjects 428 knees 1381 subjects 1621 knees ge, mean (SD) 66.7 (9.4) 65. (8.9) 62.1 (8.) BMI, mean (SD) 3.7 (4.8) 29.2 (5.5) 3. (4.9) Female, % Knee ain, % X-ray F O, % lignment, N (%) Varus 14 (62.5) 359 (83.9) 777 (47.9) Neutral 48 (21.4) 49 (11.5) 532 (32.8) Valgus 36 (16.1) 2 (4.7) 312 (19.3) 4

5 11/7/211 Study opulation 224 subjects 224 knees 35 subjects 428 knees 1381 subjects 1621 knees ge, mean (SD) 66.7 (9.4) 65. (8.9) 62.1 (8.) BMI, mean (SD) 3.7 (4.8) 29.2 (5.5) 3. (4.9) Female, % Knee ain, % X-ray F O, % lignment, N (%) Varus 14 (62.5) 359 (83.9) 777 (47.9) Neutral 48 (21.4) 49 (11.5) 532 (32.8) Valgus 36 (16.1) 2 (4.7) 312 (19.3) revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or 5

6 11/7/211 revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or revalence of med F damage exceeds that of lat F damage revalence of Med and Lat F artilage Damage or by nearly every definition. revalence of Med and Lat F artilage Damage or revalence of Med and Lat F artilage Damage or Differences are large among less severely damaged knees 6

7 revalence (%) revalence (%) 11/7/211 revalence of Med and Lat F artilage Damage or and smaller among more severely damaged knees revalence of and F artilage Damage (WORMS > 2 at or ) 84.4 ** ** 69.2 ** 55.4 F Damage F Damage 51.1 ** p < revalence of and F artilage Damage (WORMS > 5 at or ) F Damage F Damage revalence of Isolated Med and Lat F Damage or revalence of Isolated Med and Lat F Damage or revalence of isolated med F damage exceeds that of isolated lat F damage by nearly every definition revalence of Isolated Med and Lat F Damage or with large differences among less severely damaged knees 7

8 revalence (%) revalence (%) revalence (%) revalence (%) 11/7/211 revalence of Isolated Med and Lat F Damage or and smaller differences among more severely damaged knees revalence of Isolated and F artilage Damage (WORMS > 2 at or ) 16.1 ** 18.8 ** ** F Damage F Damage 7.4 ** p < revalence of Isolated and F artilage Damage (WORMS > 5 at or ) Relation to Knee lignment To what extent does the prevalence of med F cartilage damage depend on knee alignment? * F Damage F Damage * p <.5 Varus Neutral Valgus (HK < -2 ) (HK > 2 ) 1 revalence of and F artilage Damage (WORMS > 2) by lignment in 1 revalence of and F artilage Damage (WORMS > 3) by lignment in Varus Neutral Valgus % F Damage % F Damage Varus Neutral Valgus F Damage F Damage 8

9 revalence (%) revalence (%) 11/7/211 1 revalence of and F artilage Damage (WORMS > 4) by lignment in 1 revalence of and F artilage Damage (WORMS > 5) by lignment in Varus Neutral Valgus F Damage F Damage Varus Neutral Valgus F Damage F Damage onclusions Discussion revalence of medial F cartilage damage exceeded that of lateral F damage in all 3 studies and according to nearly every definition of disease Findings may have implications for interventions that assume F disease to be lateral Only among severely involved knees did the prevalence of lateral damage approximate that of medial damage The high prevalence of medial F damage persisted in all strata of knee alignment Thank You Boston Osteoarthritis of the Knee Study () supported by NIH R47785 Framingham Osteoarthritis Study () supported by NIH R1-G18393 Multicenter Osteoarthritis Study () supported by NI U1 G1882, G18832, G18947, G1969, NIHD R1-HD435 9

10 11/7/211 Due to rista Involvement? Random selection of 26 MRIs from among those previously identified with med patella damage (WORMS >2) underwent blinded re-reading 23 of 26 (88.5%; 95%I: 76.2%,1%) had damage in regions other than crista rista involvement alone not sufficient to account for high prevalence of med F damage 1