Table 1.

Studies of total hip or knee replacement reporting proportion of patients with pain at follow-up

Author, country date of baseline	Indication, population, age	Follow-up, study design, losses to follow-up	Pain outcome measure	Number of patients with
				Favourable outcome	Uncertain outcome	Unfavourable outcome
Hip replacement
Nikolajson et al,23 Denmark, 2003	Primary THR, degenerative hip arthritis N=1231 questionnaire follow-up of consecutive patients Mean age 71.6 years (SD 8.7)	12–18-month follow-up Joint registry 5.9% lost to follow-up	Authors' own scale of presence of hip pain and impact on daily life	754 (hip pain not present)	4 died 117 lost to follow-up 62 bilateral or further operation 167 hip pain still present with no/mild impact on daily life	127 (pain with moderate, severe or very severe impact on daily life)
Jones et al,24 Canada, 1995–1997	Primary THR, 94% OA N=242 consecutive patients (includes estimated lost to follow-up based on equal proportions hip/knee lost) Mean age 68.2 years (SD 11.1)	6-month follow-up Prospective 5.8% lost to follow-up or died (Losses to follow-up estimated proportionately as not reported for hip and knee separately)	WOMAC pain Losses to follow-up estimated proportionately as not reported for hip and knee separately	208 (no pain/mild pain defined as more than a 10-point gain on the 100-point WOMAC pain dimension)	14 lost to follow-up (estimated)	20 (moderate/severe pain defined as a gain of <10 points on the 100-point WOMAC pain dimension)
Quintana et al,25 Spain, 1999–2000	THR, OA N=784 consecutive patients willing to participate and with complete presurgical data Mean age 69.1 years	6-month follow-up Prospective 25.5% lost to follow-up	WOMAC pain	456 (patients reporting improvement in pain greater than minimal clinical important difference 24.55/100)	200 lost to follow-up	128 (patients reporting no improvement in pain greater than minimal clinical important difference 24.55/100)
Nilsdotter et al,26 Sweden, 1995–1998	Primary unilateral THR, OA N=219 consecutive patients with two surgical methods. For proportion with pain at follow-up N=92 Mean age 71 years (range 50–92)	Mean 43-month follow-up Prospective 5.9% lost to follow-up	WOMAC pain Favourable/unfavourable estimates based on extrapolation of partial follow-up	153 (Pain improved by more than 10/100 units reflecting detectable clinical improvement)	8 died 13 lost to follow-up	45 (Pain improved by <10/100 units reflecting no detectable clinical improvement)
Singh and Lewallen,27 USA, 1993–2005	THR, 87% OA N=9154 consecutive patients from joint registry sent postal questionnaire Mean age of patients followed up 65.0 years (SD 13)	24-month follow-up (also 60 month with greater losses to follow-up) Prospective 37.7% lost to follow-up	Single question: How much pain do you have in your operated hip? None, mild, moderate or severe	5272 (None or mild pain)	3447 lost to follow-up	435 (moderate or severe pain)
Wylde et al,28 UK, 2004–2006	THR, majority OA N=1401 consecutive patients Median age 73 years (range 65–78)	Median 41-month follow-up (range 35–48) Prospective with postal follow-up 47.6% lost to follow-up	WOMAC pain	818 (no pain for the past 3 months or mild persistent pain in replaced hip)	71 died 1 revision 667 lost to follow-up	114 (moderate or severe persistent pain for 3 months in replaced hip, WOMAC 0–75/100)
Knee replacement
Baker et al,29 UK, 2003	Primary TKR, 96% OA N=9417 questionnaire follow-up of random sample of patients in joint registry Mean age 70.7 years (range 25–98)	12-month follow-up or latest available Prospective 14.9% lost to follow-up	Oxford knee score pain dimension	6427 (did not report persistent knee pain)	1407 lost to follow-up or died	1583 (reported persistent knee pain)
Jones et al,24 Canada, 1995–1997	Primary TKR, 94% OA N=292 consecutive patients (includes estimated lost to follow-up based on equal proportions hip/knee lost) Mean age 69.2 years (SD 9.2)	6-month follow-up Prospective 5.5% lost to follow-up or died (estimated proportionately as not reported for hip and knee separately)	WOMAC pain Losses to follow-up estimated proportionately as not reported for hip and knee separately	222 (no pain/mild pain defined as more than a 10-point gain on the WOMAC pain dimension)	16 lost to follow-up or died (estimated)	54 (moderate /severe pain defined as a gain of <10 points on the WOMAC pain dimension)
Quintana et al,25 Spain, 1999–2000	TKR, OA N=792 consecutive patients willing to participate and with complete presurgical data Mean age 71.9 years	6-month follow-up Prospective 24.1% lost to follow-up	WOMAC pain	402 (patients reporting improvement in pain greater than minimal clinical important difference 22.6/100)	191 lost to follow-up	199 (patients reporting no improvement in pain greater than minimal clinical important difference 22.6/100)
Núñez et al,30 Spain, 2000–2001	Primary TKR, OA N=88 consecutive patients Mean age 74.8 years (SD 5.6)	36-month follow-up Prospective 8.0% lost to follow-up	WOMAC pain	60 (improvement in postoperative pain scores)	1 died 7 lost to follow-up 13 contralateral or other surgery	7 (no improvement in postoperative pain scores)
Stephens et al,31 USA	TKR, OA N=68 patients referred for knee replacement aged 50 years or older Mean age 67.4 years	6-month follow-up Prospective 7.4% lost to follow-up	WOMAC	52 (decrease in pain)	5 lost to follow-up	11 (no change or increase in pain)
Lundblad et al,32 Sweden	TKR, OA N=69 patients scheduled for knee replacement Mean age 68 years (range 40–80)	18-month follow-up Prospective 10.1% lost to follow-up (including deaths)	VAS pain	21 (no pain at rest or with movement)	7 lost to follow-up or died 26 pain with movement	15 (pain at rest and movement)
Nilsdotter et al,33 Sweden, 1999–2001	Primary TKR, OA N=102 responders to postal survey on waiting list for knee replacement Mean age 71 years (SD 8, range 51–86)	60-month follow-up Prospective 12.7% lost to follow-up	KOOS pain compared with preoperatively	47 (much less or less pain than preoperatively)	9 died 13 lost to follow-up 6 operated bilaterally	27 (similar or more pain than preoperatively)
Vuorenmaa et al,34 Finland	TKR, OA N=51 patients referred for knee replacement Mean age 70 (SD 5)	3-month follow-up Prospective 11.8% lost to follow-up	VAS pain Pain calculated from 20% followed up had moderate or severe pain (defined as score of >30 on a 100-mm pain VAS)	34 (none or mild pain)	1 died 6 lost to follow-up 1 infection	9 (moderate or severe pain)
Czurda et al,35 Austria, 2003–2005	Primary TKR, OA N=411 consecutive patients with computer-assisted or conventional surgery with at least 18-month follow-up Mean age 75–76 years (range 45–96)	Mean 26-month follow-up (range 18–42) 13.4% lost to follow-up	WOMAC pain	273 (no report of painful knees—no moderate or worse response in any WOMAC pain dimension)	2 died 55 lost to follow-up 24 infection, trauma, reoperation, poor general condition	57 (painful knees—moderate or worse response in any WOMAC pain dimension)
Wylde et al,28 UK, 2004–2006	TKR, majority OA N=1394 consecutive patients Median age 73 (range 28–96)	Median 41-month follow-up (range 34–49) Prospective with postal follow-up 45.3% lost to follow-up	WOMAC pain	433 (no pain for the past 3 months or mild persistent pain in replaced hip)	62 died 4 revision 696 lost to follow-up	199 (moderate or severe persistent pain for 3 months in replaced hip, WOMAC 0–75/100)
Brander et al,36 USA, 1998–2000	Primary TKR, 94% OA N=116 consecutive patients (1 surgeon) Mean age 66 years (SD 10.5, range 36–85)	12-month follow-up Prospective 0% lost to follow-up	VAS pain	98 (no significant pain, VAS score ≤40)	1 died 2 revision or dislocation	15 (significant pain, VAS score >40)

Studies ordered within hip and knee replacement groups by decreasing representativeness (multiple compared with single centre) and by increasing losses to follow-up.

KOOS, Knee Osteoarthritis Outcome Score; THR, total hip replacement; TKR, total knee replacement; OA, osteoarthritis; VAS, visual analogue scales; WOMAC, Western Ontario and McMaster Universities Arthritis Index.