Table 1

Details of included radiography studies

Author, year	Additional information	Sex	Age	N (knees)	Diagnostic criteria	Isolated PF OA (%)			Combined (%)	Unclear PF OA (%)			Severity
						Overall	Medial	Lateral	PF + TF OA	Overall	Medial	Lateral
Community-based population
Al-Arfaj and Al-Boukai18 2002	First two patients visiting a clinical invited everyday	F	40±15	133	KL					81			Definite
		M	40±15	167	KL					88			Definite
Baker et al, 19 2004	Randomly from community over the age of 60 years	F	68±6	1475	KL	8			26				Definite
		M	69±6	997	KL	9			12				Definite
Braga24 2009	African-Americans (>45 years) recruited by probability sampling	F	62±11	283	KL					53			Definite
		M	60±11	147	KL					60			Definite
	Caucasians (>45 years) recruited by probability sampling	F	62±11	799	KL					42			Definite
		M	61±10	728	KL					54			Definite
Cho26 2016	Random sample of individuals (>65 years) selected from a longitudinal study	F	72±5	383		3	0	2	28	29	2	15	Definite
		M	71±5	298		5	1	4	8	13	1	7	Definite
Cicuttini28 1997	Unrelated women selected from a group participating in twin study of OA	F	59±7	325	Burnett, 1994 (JSN and osteophyte)	13			15				Mild
Gross39 2012	Offspring (and their spouses) of participants from original Framingham Heart Study and population-based sample of Framingham community	FM	63±9	985 (1159)	OARSI					8			Definite
Hunter Zhang46 2007	Random sample from Health ABC study	FM	74±3	595	OARSI					49			Mild
Lanyon54 1998	Random sampling, stratified by age from the lists of two general practitioner	FM	62 (40–80)	452	Altman					13			Definite
Szoeke75 2006	Postmenopausal women selected from another population-based study	F	60±3	224	OARSI					22			Mild
Tangtrakulwanich76 2012	Individuals (>40 years) without rheumatic diseases using primary care	FM	>40	576	0–3 scale					38			Mild
Healthy individuals
Englund34 2005		FM	56±21	68	OARSI					9			Mild
McAlindon60 1992		M	>55	78						5			Mild
		F	>55	162						5			Mild
Naredo63 2005		FM	68±8	10	KL					70			Mild
Spector72 1996		F	54±6	215	KL					28			Mild
Knee pain or symptomatic population
Barret21 1990		FM	78 (51–93)	1894 (2197)	Alhback					18			Mild
Bennett22 2007		FM	54±13	39	ACR					62			Mild
Davies32 2002		FM	>40	174 (206)	Ahlback	9			13				Mild
Duncan2 2006		FM	66 (50–93)	777	KL	24			40				Definite
Hinman42 2014		FM	54±10	224		25	3	11	44				Definite
Kumm52 2012	6-year follow-up	FM	51±6	128	Line drawing atlas	19			38				Mild
Lacey53 2008		F	50–64	200	KL	19			27				Definite
		M	50–64	158		35			25				Definite
		F	>65	207		21			47				Definite
		M	>65	180		24			62				Definite
McAlindon60 1992		M	>55	86	KL					12			Mild
		F	>55	187						26			Mild
McAlindon59 1996		FM	81±5	608	Osteophyte/JSN	5			20				Definite
Neame64 2004	Right knee	FM	64±9	1729 (1718)						14			Definite
	Left knee	FM		(1723)						14			Definite
Sadat Ali69 1996		M	41±7	103 (126)	JSN, osteophytes and varus deformity	45			30				Mild
Thorstensson77 2009			45 (35–54)	125	JS width <5 mm					33			Mild
Radiographic knee OA or high risk of knee OA
Eti36 1998	Knee OA	FM	56±11	240 (369)	Altman					34			Unclear
Glass38 2014	Knee OA or High risk	F	62±8	1618 (3236)	KL					22			Definite
	Knee OA or High risk	M	62±8	1094 (2188)	KL					18			Definite
Huang43 2000	Hand, hip or knee OA	F	64 (29–87)	270	KL					62			Definite
Jones48 1993	Knee OA	FM	62 (18–91)	30 (60)	Osteophyte					75			Mild
Radiographic and symptomatic OA
Cicuttini27 2002		M	63±10	44	Osteophyte and JSN					48			Definite
		F	63±10	66	Osteophyte and JSN					38			Definite
Cooper30 1994		FM	>55	109	Radiograph atlas of knee OA	31							Mild
Elahi33 2000		FM	66±11	292	OARSI	11							Mild
Ersoz35 2003		FM	62±9	20 (40)	KL					88			Mild
Farrokhi37 2013		FM	65±9	167	KL					80			Mild
Hinman41 2002		FM	68±7	41	ACR					81			Mild
Hunter Niu45 2005		F	68±6	1500	KL					36			Mild
		M	74±3	595	KL					26			Mild
Kerna50 2013		FM	45±6	438	Line drawing atlas					48			Mild
Ledingham55 1993		FM	65 (34–91)	252	Modified Thomas 1995	24			64				Definite
Messier61 2005		FM	74±1	10	KL					90			Mild
Szebenyi74 2006			66±10	167 (334)	OARSI					65			Mild
Van der Esch78 2014		FM	62±8	298	Osteophyte					86			Mild
Post-traumatic population
Ahn17 2012	Postoperative ACLR	FM	29±9	117	IKDC					60			Mild
Barenius20 2014	ACLR with patellar graft	FM	39±6	69	KL					32			Definite
	Uninjured contralateral	FM			KL					12			Definite
	Semitendinosus ACLR graft	FM	42±7	65	KL					36			Definite
Barenius20 2014	Uninjured contralateral	FM	42±7	65	KL					12			Definite
Bourke23 2012	Isolated ACL injury with ACLR	FM		118	IKDC					12			Mild
Cohen29 2007	ACLR	FM	27 (15–46)	62	Fairbank					74			Mild
Culvenor31 2014	ACLR	FM	45±10	36	OARSI	20				48			Mild
Englund34 2005	Medial meniscectomy	FM	54±11	250	OARSI				19				Mild
	Lateral meniscectomy	FM	54±11	67	OARSI				27				Mild
Hertel40 2005	ACLR—patellar	FM	42 (22–62)	67	IKDC					19			Mild
Hulet44 2015	Arthroscopic partial lateral meniscectomy	FM	57±12	89	IKDC				33				Mild
Jarvela47 2001	ACLR with patellar graft	FM	31 (15–61)	100	IKDC					47			Mild
Keays49 2007	ACLR with patellar/semitendinosus and gracilis graft	FM	27 (18–38)	56					25				Mild
Li56 2011	ACLR	FM	26±10	249	KL					11			Mild
Li56 2011	Uninjured contralateral	FM	26±10	249	KL					3			Mild
Liden57 2008	ACLR with patellar graft	FM	30 (17–52)	72	Ahlback and Fairbank					14			Mild
	ACLR with hamstring graft	FM	29 (15–59)	41						5			Mild
Lohmander58 2004	ACL injury with surgery	F	31 (26–40)	41	OARSI					20			Mild
	ACL injury without surgery	F	31 (26–40)	26						4			Mild
Murray62 2012	ACLR with patellar graft	FM		83	IKDC					76			Mild
	Uninjured contralateral	FM		42						59			Mild
Neuman65 2009	ACL injury with meniscal injury	FM	43±8	22	OARSI					18			Mild
	ACL injury without meniscal injury	FM	43±8	38	OARSI					3			Mild
Neuman65 2009	ACLR with meniscal injury	FM	43±8	11	OARSI					55			Mild
	ACLR without meniscal injury	FM	43±8	4	OARSI					25			Mild
	Overall (ACL with or with meniscal or reconstruction)	FM	43±8	75	OARSI				9				Mild
Oiestad66 2013	ACLR	FM	71±8	181						26			Mild
Roth67 1985	ACLR (non-augmented)	FM		38	Osteophyte size						13	40	Mild
	ACLR (augmented)	FM		43	Osteophyte size						4	14	Mild
Sajovic70 2006	ACLR with semitendinosus and gracilis	FM	24 (14–42)	28	IKDC					7			Mild
	ACLR patellar tendon	FM	27 (16–46)	26	IKDC					12			Mild
Salmon71 2006	ACLR—13-year follow-up	FM	27 (25–28)	43	IKDC					26			Mild
Sward73 2013	ACL injured (with or without ACLR) with varus alignment	FM	42±7	36	OARSI				22				Mild
	ACL injured (with or without ACLR) with valgus/neutral	FM	39±6	29	OARSI				7				Mild
Occupation-based population
Kujala51 1995	Long distance runners	M	60±5	28	KL					11			Definite
	Soccer players	M	57±5	31	KL					16			Definite
	Weight lifters	M	60±5	29	KL					28			Definite
	Shooters	M	61±5	29	KL					3			Definite
Rytter68 2009	Floor layers	M	53 (39–68)	134	Modified Ahlback Scale					9			Mild
Rytter68 2009	Graphic designers	M	58 (40–70)	120	Modified Ahlback Scale					18			Mild
Spector72 1996	Ex-athletes	F	52±6	81	KL					42			Mild
Tangtrakulwanich76 2006	Monk		44±18	261	KL	19			33				Mild

Where possible, age is presented as mean±SD or mean (range).
Mild severity indicates at least mild OA severity and definite indicates definite OA severity (equivalent to KL≥2).
ACLR, ACL reconstruction; ACR, American College Rheumatology; F, female; FM, both female and male; IKDC, International Knee Documentation Committee; JSN, joint space narrowing; M, male; OA, osteoarthritis; OARSI, Osteoarthritis Research Society International; PF OA, patellofemoral osteoarthritis.