Fourth-Generation Total Wrist Arthroplasty: A Systematic Review of Clinical Outcomes

Abstract

Background  The purpose of total wrist arthroplasty is to reduce pain and maintain mobility in a painful destructed wrist. First-, second-, and third-generation total wrist arthroplasties have shown unacceptable outcomes with high failure rates. In 2004, the fourth-generation total wrist implants were introduced to address the clinical problems encountered in the previous generations of total wrist implants.

Methods  Outcomes and complications of fourth-generation total wrist implants were systematically reviewed in the literature (2004–present), including the Universal 2, ReMotion, Freedom, Motec, and Maestro total wrist implants.

Results  The literature search yielded 114 papers, of which 18 (990 implants) were included in this systematic review. The quality of evidence was low. All implants effectively reduced pain and improved functionality of the wrist. The Motec wrist implant demonstrated the highest survival rate at 10 year follow-up (86%).

Conclusion  This systematic review suggests a substantial improvement of quality in fourth-generation total wrist arthroplasty.

Degeneration of the wrist joint can be the result of systemic diseases such as rheumatoid arthritis (RA), trauma, or osteoarthritis. A destructed wrist causes pain, swelling, deformity, limited range of motion, and reduced grip strength. Although a total wrist arthrodesis adequately treats pain, the range of motion is completely absent in the radio- and midcarpal joint. Total wrist arthroplasty (TWA) by means of an implant was developed not only to treat pain, but also to maintain some wrist mobility. Gluck was the first to use a total wrist implant in the 1890s. ¹ Unacceptable outcomes, especially in terms of survivability, of early generation TWA were found in the literature (survival rate: BIAX 0.83 at 10 years; Meuli 0.77 at 8 years; Universal 1 0.40 at 10 years). ² These results motivated the development of the Universal 2 (Integra LifeSciences, Plainsboro, NJ), whose operative technique was first described by Adams. ³ The fourth generation of TWAs nowadays includes the Universal 2, ReMotion (Small Bone Innovation, Morristown, PA), Freedom (Integra, Plainsboro, NJ), Motec (Swemac Orthopaedics AB, Linköping, Sweden), and Maestro (Biomet, Warsaw, IN) implants. This systematic review reports on survival rate, outcomes, and complications of these implants.

Methods

The guidelines of the PRISMA statement 2009 were followed for this systematic review. ⁴

Literature Search

A literature search was performed in databases EMBASE, PubMed (MEDLINE), and the COCHRANE Library. The search strategy included a general section ( total wrist arthroplasty and fourth generation) and a specific section ( Universal 2, ReMotion, Maestro, Freedom , and Motec total wrist arthroplasty) ( Table 1 ). We restricted the search to the 2004 to 2021 period, considering the Universal 2 TWA was introduced in 2004. Furthermore, additional eligible publications were searched in the reference lists of relevant papers.

Table 1. Search strategy EMBASE, PubMed/MEDLINE, and COCHRANE library.

Search strategy EMBASE 22–11–2018 ( ((exp “wrist prosthesis”/ OR “wrist prostheses.”mp OR “wrist prosthesis.”mp OR “wrist joint prostheses.”mp OR “wrist joint prosthesis.”mp OR ((“Joint Prosthesis”/ OR “prosthesis.”mp OR “prostheses.”mp OR prosthe*.mp) AND (exp “Wrist”/ OR “wrist.”mp OR “wrists.”mp OR “Triangular Fibrocartilage.”mp))) AND (“universal 2.”mp OR “universal ii.”mp OR “universal two.”mp OR “universal2.”mp OR “universalii.”mp OR “universaltwo.”mp OR “universal total wrist.”mp OR “Re-motion.”mp OR “Remotion.”mp OR Re-motion*.mp OR Remotion*.mp OR “freedom prosthesis.”mp OR “Motec.”mp OR motec*.mp OR “Maestro.”mp OR maestro*.mp OR “4th generation.”mp OR “4th gen.”mp OR “fourth generation.”mp OR “generation 4.”mp OR “generation four.”mp)) OR ((exp “Wrist”/ OR “wrist.”mp OR “wrists.”mp OR “Triangular Fibrocartilage.”mp OR “TWA.”mp OR “TWAs.”mp OR “total wrist arthroplasty.”mp OR “total wrist implant.”mp OR “total wrist prosthesis.”mp OR “wrist arthroplasty.”mp OR “wrist implant.”mp OR “wrist prosthesis.”mp OR “wrist arthroplasties.”mp OR “wrist implants.”mp) AND (“universal 2.”mp OR “universal ii.”mp OR “universal two.”mp OR “universal2.”mp OR “universalii.”mp OR “universaltwo.”mp OR “universal total wrist.”mp OR “Re-motion.”mp OR “Remotion.”mp OR Re-motion*.mp OR Remotion*.mp OR “freedom prosthesis.”mp OR “Motec.”mp OR motec*.mp OR “Maestro.”mp OR maestro*.mp OR “4th generation.”mp OR “4th gen.”mp OR “fourth generation.”mp OR “generation 4.”mp OR “generation four.”mp)) ) AND (2004 OR 2005 OR 2006 OR 2007 OR 2008 OR 2009 OR 2010 OR 2011 OR 2012 OR 2013 OR 2014 OR 2015 OR 2016 OR 2017 OR 2018 OR 2019).yr NOT ((exp “Case Report”/ OR “case report.”ti OR “Review”/) NOT (“Clinical Study”/ OR exp “Clinical Trial”/)) Search strategy PubMed/MEDLINE 22–11–2018 (((“wrist prostheses”[tw] OR “wrist prosthesis”[tw] OR “wrist joint prostheses”[tw] OR “wrist joint prosthesis”[tw] OR ((“Joint Prosthesis”[mesh:noexp] OR “prosthesis”[tw] OR “prostheses”[tw] OR prosthe*[tw]) AND (“Wrist”[mesh] OR “Wrist Joint”[mesh] OR “wrist”[tw] OR “wrists”[tw] OR “Triangular Fibrocartilage”[tw]))) AND (“universal 2”[tw] OR “universal ii”[tw] OR “universal two”[tw] OR “universal2”[tw] OR “universalii”[tw] OR “universaltwo”[tw] OR “universal total wrist”[tw] OR “Re-motion”[tw] OR “Remotion”[tw] OR Re-motion*[tw] OR Remotion*[tw] OR “freedom prosthesis”[tw] OR “Motec”[tw] OR motec*[tw] OR “Maestro”[tw] OR maestro*[tw] OR “4th generation”[tw] OR “4th gen”[tw] OR “fourth generation”[tw] OR “generation 4”[tw] OR “generation four”[tw])) OR ((“Wrist”[mesh] OR “Wrist Joint”[mesh] OR “wrist”[tw] OR “wrists”[tw] OR “Triangular Fibrocartilage”[tw] OR “TWA”[tw] OR “TWAs”[tw] OR “total wrist arthroplasty”[tw] OR “total wrist implant”[tw] OR “total wrist prosthesis”[tw] OR “wrist arthroplasty”[tw] OR “wrist implant”[tw] OR “wrist prosthesis”[tw] OR “wrist arthroplasties”[tw] OR “wrist implants”[tw]) AND (“universal 2”[tw] OR “universal ii”[tw] OR “universal two”[tw] OR “universal2”[tw] OR “universalii”[tw] OR “universaltwo”[tw] OR “universal total wrist”[tw] OR “Re-motion”[tw] OR “Remotion”[tw] OR Re-motion*[tw] OR Remotion*[tw] OR “freedom prosthesis”[tw] OR “Motec”[tw] OR motec*[tw] OR “Maestro”[tw] OR maestro*[tw] OR “4th generation”[tw] OR “4th gen”[tw] OR “fourth generation”[tw] OR “generation 4”[tw] OR “generation four”[tw]))) AND (“2004/01/01”[PDAT]: “3000/12/31”[PDAT])) NOT ((“Case Reports”[ptyp] OR “case report”[ti] OR “Review”[ptyp]) NOT “Clinical Study”[ptyp]) COCHRANE library 22–11–2018 ((“Wrist” OR “wrist” OR “wrists” OR “Triangular Fibrocartilage”) AND (“universal 2” OR “universal ii” OR “universal two” OR “universal2” OR “universalii” OR “universaltwo” OR “universal total wrist” OR “Re-motion” OR “Remotion” OR Re-motion* OR Remotion* OR “freedom prosthesis” OR “Motec” OR motec* OR “Maestro” OR maestro* OR “4th generation” OR “4th gen” OR “fourth generation” OR “generation 4” OR “generation four”)):ti,ab,kw OR ((“Wrist” OR “wrist” OR “wrists” OR “Triangular Fibrocartilage” OR “TWA” OR “TWAs” OR “total wrist arthroplasty” OR “total wrist implant” OR “total wrist prosthesis” OR “wrist arthroplasty” OR “wrist implant” OR “wrist prosthesis” OR “wrist arthroplasties” OR “wrist implants”) AND (“universal 2” OR “universal ii” OR “universal two” OR “universal2” OR “universalii” OR “universaltwo” OR “universal total wrist” OR “Re-motion” OR “Remotion” OR Re-motion* OR Remotion* OR “freedom prosthesis” OR “Motec” OR motec* OR “Maestro” OR maestro* OR “4th generation” OR “4th gen” OR “fourth generation” OR “generation 4” OR “generation four”)) ) :ti,ab,kw

Inclusion and Exclusion Criteria

Randomized controlled trials (RCTs), cohort studies, and case series reporting on outcomes on fourth-generation TWAs (Universal 2, ReMotion, Freedom, Motec, and Maestro total wrist arthroplasty) in at least 10 patients/wrists with a minimal follow-up of 2 years were included. Papers that describe total wrist implant replacement (secondary implants) used as salvage procedure for failed primary total wrist implants were excluded. All inclusion and exclusion criteria are listed in Table 2 .

Table 2. Inclusion and exclusion criteria.

Inclusion criteria	Exclusion criteria
▪ Studies reporting on Universal 2, ReMotion, Freedom, Motec, and/or Maestro total wrist arthroplasty ▪ Studies that evaluate primary total wrist implants ▪ Evaluated implants, n  ≥ 10 ▪ Follow-up ≥ 2 years ▪ RCTs and observational studies (cohort studies and case series) ▪ Reported outcome measures; at least survival rate and complications ▪ Publishing year ≥ 2004	▪ No full text available despite contacting author ▪ Case reports or review studies ▪ Biomechanical studies ▪ Studies not accessible in journals or books ▪ Cadaver studies ▪ Wrist hemiarthroplasty (radial or carpal component) ▪ Studies written in language other than English ▪ Double publications ▪ Secondary implants

Abbreviation: RCT, randomized controlled trial.

Study Selection

Two authors (H.J.A.Z. and A.B.) independently screened paper titles and abstracts. A second selection, made in a similar manner, was made by assessment of full-text papers. Those that fell within the inclusion criteria were included in the systematic review.

Data Extraction, Analysis, Quality Assessment, and Handling of Data

We focused on the methodology, number of cases, and the observation period. Single or multiple implant-type publications with less than 10 implants were considered as not useful. Publications that describe implant types with more than 10 implants were evaluated in this study. Authors who published different papers concerning the same implant series were contacted to clarify patient inclusion and previous publications reporting on same patients were excluded. Implant survival was evaluated by cumulated implant survival of at least 5 years. Implant revision was reported as “revision rate” and was evaluated in case no cumulated implant survival rate was available. Functional outcomes of the implants had to be evaluated by validated outcomes measurement tools.

The GRADE approach ⁵ was used by two the authors (H.J.A.Z. and A.B) to assess the quality of the included studies. The quality is rated high, moderate, low, or very low. The start rating is determined by study design: high for RCTs, low for observational studies, and very low for retrospective case series. The rating can be downgraded by one or two in case of risk of bias, inconsistency, indirectness, imprecision, or publication bias. Consensus (H.J.A.Z. and A.B.) resolved any disagreements between the two researchers (H. J.A.Z. and A.B.) regarding study selection or quality assessment.

Results

The literature search revealed 77 unique papers, of which 18 complied to our inclusion criteria ^{6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23} ( Fig. 1 ). Fourteen papers reported preoperative validated outcome measurements and are reported in ( Table 3 ). Two papers ^{24 25} were excluded because the results were also reviewed in another paper by the same author. ¹⁰

Fig. 1.

Flow diagram of systematic literature search and study selection, according to PRISMA.

Table 3. Implant type, patient characteristics, satisfaction, and validated outcomes measurements in 16 publications.

Author, year	Country	Type study	Implant type	Implants (RA), n	Preoperative data	Validated outcome measure instrument	Change in scores, points	p -Value	Patient satisfaction	GRADE quality assessment
Ferreres et al, 2011	Spain	Retrospective	Universal 2	21 (14)	Not reported	PRWE	–	–	95% (very) satisfied	Very low
Morapudi et al, 2012	United Kingdom	Prospective	Universal 2	21 (19)	Reported	DASH	Improved 10.3	<0.001	–	Low
						PRWE	Improved 45.6	<0.001
Badge et al, 2016	United Kingdom	Prospective	Universal 2	85 (85)	Reported	VAS	Improved 2.7	<0.001	–	Low
						QDASH	Improved 15.5	<0.001
						Wrightington Wrist	Improved 2.2	<0.001
Gil et al, 2017	United States	Retrospective	Universal 2	39 (31)	Reported	VAS	Improved 8.1	<0.001	–	Very low
Pfanner et al, 2017	Italy	Retrospective	Universal 2	23 (23)	Partially reported	VAS	Improved 8.2	–	100% satisfied	Very low
						QDASH	–	–
						PRWHE	–	–
Kennedy et al, 2018	United Kingdom	Retrospective	Universal 2	48 (34)	Reported	DASH	Improved 32.8	<0.001	87% satisfied	Very low
Zijlker et al, 2019	Netherlands	Retrospective	Universal 2	26 (14)	Not reported	QDASH	–	–	92% (very) satisfied	Very low
						PRWHE	–	–
						VAS	–	–
Sagerfors et al, 2015	Sweden	Prospective	Universal 2	12 (12)	Reported	VAS	Improved 3.7	<0.001	–	Low
						COPM p	Improved 3.8	0.020
						COPM s	Improved 2.7	0.008
						DASH	Improved 13.7	0.030
						PRWHE	Improved 28.0	0.010
			Maestro	68 (55)	Reported	VAS	Improved 4.2	<0.001	–
						COPM p	Improved 4.2	<0.001
						COPM s	Improved 4.6	<0.001
						DASH	Improved 16.8	0.001
						PRWHE	Improved 47.0	<0.001
			ReMotion	87 (68)	Reported	VAS	Improved 3.5	<0.001	–
						COPM p	Improved 2.6	<0.001
						COPM s	Improved 4.0	<0.001
						DASH	Improved 12.3	<0.001
						PRWHE	Improved 37.5	<0.001
Herzberg, 2011	France	Prospective	ReMotion	20 (13)	Reported	VAS	RA: improved 6.0	–	–	Low
							Non-RA: improved 4.0	–
Cooney et al, 2012	United States	Retrospective	ReMotion	22 (NA)	Not reported	Mayo	–	–	–	Very low
						DASH	–	–
						PRWE	–	–
Herzberg et al, 2012	France	Prospective	ReMotion	215 (129)	Reported	VAS	RA: improved 4.8	–	RA: 88% (very) satisfied	Low
							Non-RA: improved 5.4	–	Non-RA: 95% (very) satisfied
						QDASH	RA: improved 20.0	–
							Non-RA: 21.0	–
Bidwai et al, 2013	United Kingdom	Prospective	ReMotion	10 (10)	Reported	VAS	Improved 5.3	<0.05	Mean score: 7.5/10	Low
Boeckstyns et al, 2013	Denmark	Prospective	ReMotion	65 (50)	Reported	VAS	Improved 4.0	0.001	–	Low
						QDASH	Improved 16.0	0.030
Honecker et al, 2019	France	Prospective	ReMotion	23 (19)	Reported	VAS	Improved 4.0	<0.05	–	Low
						QDASH	Improved 20.0	<0.05
Nydick et al, 2012	United States	Retrospective	Maestro	23 (5)	Partially reported	VAS	Improved 5.8	<0.050	–	Low
						Mayo	–	–
						DASH	–	–
Gaspar et al, 2016	United States	Retrospective	Maestro	47 (29)	Not reported	–	–	–	–	Very low
Giwa et al, 2018	United Kingdom	Prospective	Motec	25 (4)	Reported	DASH	Improved 36.6	<0.001	–	Low
						Mayo	Improved 32.1	<0.001
Reigstad and Røkkum, 2018	Norway	Prospective	Motec	110 (0)	Reported	VAS	Improved 2.8	–	–	Low
						QDASH	Improved 15.0	–
						PRWHE	Improved 25.0	–

Abbreviations: COPM p/s, Canadian Occupational Performance Measure performance/satisfaction; NA, nonavailable; non-RA, non-rheumatoid arthritis; PRW(H)E, patient rated wrist (hand) evaluation; (Q)DASH, (quick) disability of the arm shoulder and hand; RA, rheumatic arthritis; VAS, visual analog scale.

Universal 2 Implant

Seven papers described 275 Universal 2 implants, concerning 243 cases (84%) with RA. ^{8 17 18 19 20 21 22 23} Pre- and postoperative functional outcomes were measured in four papers and all improved significantly. ^{8 17 20 21} Four papers reported VAS (visual analog scale) scores and showed an evident reduction of pain. ^{8 17 19 22} The flexion–extension arc at the wrist joint consisted of a mean 65 degrees ( Table 4 ). This was significantly improved compared with preoperative motion in two of the three papers. ^{17 21} Improvement of grip strength was only described in one paper. ¹⁷ Patient satisfaction was evaluated in four papers and was high (87–100% satisfaction). ^{18 20 22 23} One paper assessed return to work and it was 100% ( Table 5 ). ²²

Table 4. Postoperative wrist motion and grip strength.

Author, year	Implant type	Flexion-extension arc		Radial-ulnar arc		Active range of motion		Grip strength
		Change compared with preoperatively, degrees	p -Value	Change compared with preoperatively, degrees	p -Value	Change compared with preoperatively, degrees	p -Value	Change compared with preoperatively, kg	p -Value
Ferreres et al, 2011	Universal 2	–	–	–	–	–	–	–	–
Morapudi et al, 2012	Universal 2	Improved 15	<0.050	–	–	–	–	–	–
Badge et al, 2016	Universal 2	Improved 20	<0.050	Declined 3	NS	–	–	Improved 5.4	<0.001
Gil et al, 2017	Universal 2	–	–	–	–	–	–	–	–
Pfanner et al, 2017	Universal 2	–	–	–	–	–	–	–	–
Kennedy et al, 2018	Universal 2	–	–	–	–	–	–	–	–
Zijlker et al, 2019	Universal 2	–	–	–	–	–	–	–	–
Sagerfors et al, 2015	Universal 2	None	NS	None	NS	–	–	–	NS
	Maestro	Improved 10	–	Improved 5	–	–	–	Improved (kg not described)	<0.005
	ReMotion	None	NS	None	NS	–	–	Improved (kg not described)	<0.005
Herzberg, 2011	ReMotion	–	–	RA: improved 15		–	–	Improved 4.0	–
		Improved 4	–	Non-RA: improved 2	–	–	–	Improved 1.0	–
Cooney et al, 2012	ReMotion	Declined 9	–	Declined 8	–	–	–	–	–
Herzberg et al, 2012	ReMotion	–	–	–	–	–	–	RA: improved 40%	–
		–	–	–	–	–	–	Non-RA: improved 19%	–
Bidwai et al, 2013	ReMotion	Improved 37	<0.050	–	–	–	–	Improved 5.8	NS
Boeckstyns et al, 2013	ReMotion	Improved 3	NS	Improved 4	–	–	–	Improved 5.0	0.030
Honecker et al, 2019	ReMotion	Improved 13.3	<0.050	–	–	–	–	Improved 6.3	<0.050
Nydick et al, 2012	Maestro	Improved 5	NS	Improved 8	NS	–	–	–	–
Gaspar et al, 2016	Maestro	–	–	–	–	–	–	–	–
Giwa et al, 2018	Motec	Improved 34	<0.001	Improved 35	NS	–	–	Improved 15.6	<0.010
Reigstad and Røkkum, 2018	Motec	–	–	–	–	Improved 35	–	Improved 5.0	–

Abbreviations: non-RA, nonrheumatoid arthritis; NS, nonsignificant; RA, rheumatoid arthritis.

Table 5. Cumulated survival/revision rate and return to work.

Author, year	Implant type	Cumulated survival				Revision rate	Return to work rate	Mean follow-up (range), years
		At 5 years	At 8 years	At 10 years	At 15 years
Ferreres et al, 2011	Universal 2	1.00	1.00	–	–	–	–	5.5 (3.2–8.8)
Morapudi et al, 2012	Universal 2	–	–	–	–	0/21	–	3.1 (1.8–3.9)
Badge et al, 2016	Universal 2	0.91	0.91	–	–	–	–	4.4 (2.0–10.0)
Gil et al, 2017	Universal 2	1.00	0.91	0.91	0.78	–	–	9.0 (5.0–15.0)
Pfanner et al, 2017	Universal 2	0.84	0.75	0.64	–	–	15/15	6.9 (2.0–12.0)
Kennedy et al, 2018	Universal 2	0.85	–	–	–	–	–	7.0 (3.5–11.0)
Zijlker et al, 2019	Universal 2	0.96	0.92	0.81	–	–	–	11.0 (8.0–13.0)
Sagerfors et al, 2015 a	Universal 2	0.90	0.90	–	–	–	–	8.0 (SD 2.5)
Mean		0.92	0.89	0.78	0.78			6.8
Sagerfors et al, 2015 a	ReMotion	0.99	0.94	–	–	–	–	7.0 (SD 3.1)
Herzberg, 2011	ReMotion	–	–	–	–	0/20	RA: 2/2	2.5 (1.0–6.3)
							Non-RA: 3/4
Cooney et al, 2012	ReMotion	1.00	1.00	–	–	–	–	6.0 (3.5–15.0)
Herzberg et al, 2012	ReMotion	0.92	0.92	–	–	–	–	4.0 (2.0–8.0)
Bidwai et al, 2013	ReMotion	–	–	–	–	0/10	–	2.7 (1.0–5.0)
Boeckstyns et al, 2013	ReMotion	0.95	0.90	–	–	–	–	6.0 (5.0–9.0)
Honecker et al, 2019	ReMotion	0.93	–	0.69	–	4/23	–	6.0 (1.0–10.3)
Mean		0.96	0.94	0.69	–			4.9
Sagerfors et al, 2015*	Maestro	0.95	–	–	–	–	–	5.0 (SD 1.0)
Nydick et al, 2012	Maestro	–	–	–	–	2/23	–	2.1 (0.3–4.6)
Gaspar et al, 2016	Maestro	–	–	–	–	14/47	–	2.9 (1.0–12.6)
Mean		0.95	–	–	–			3.3
Giwa et al, 2018	Motec	0.96	–	–	–	–	9/14	4.2 (2.2–5.5)
Reigstad and Røkkum, 2018	Motec	0.90	0.86	0.86	–	–	–	8.0 (5.0–11.0)
Mean		0.93	0.86	0.86	–			6.1

Abbreviation: SD, standard deviation.

^aSame study.

Maestro Implant

Three papers described 138 Maestro implants, concerning 89 RA cases (64%). ^{6 7 8} Two papers evaluated pain scores and both demonstrated a statistically significant reduction. ^{7 8} One paper evaluated functional outcomes and described a significant improvement in DASH, PRWHE, and COPM scores. ⁸ The mean flexion–extension arc of this implant was only described in one paper and increased 5 to 10 degrees to a mean of 90 degrees after surgery. ⁷ One paper described that grip strength had improved significantly. ⁸ The included papers did not evaluate patient satisfaction nor return to work.

ReMotion Implant

Seven papers described 442 ReMotion implants, concerning 289 (65%) RA cases. ^{8 11 12 13 14 15 16} Six papers described pain scores ^{8 11 12 14 15 16} and all six showed an improvement in VAS scores. In four papers this improvement was significant. ^{8 11 12 16} Functional outcomes were described in four papers that all described a statistically significant improvement compared with preoperative values. ^{8 12 15 16} The mean postoperative flexion–extension arc of the ReMotion implant was 61 degrees, which significantly improved compared with preoperative motion in two papers. ^{11 16} Grip strength was improved in six papers, three papers described a significant improvement. ^{8 12 16} Return to work after surgery was evaluated in one paper and was high (83%). Patient satisfaction was evaluated in two papers and was high. ^{11 15}

Motec Implant

Two papers described 135 Motec implants. ^{9 10} Pain was evaluated in one paper that showed a significant reduction. ¹⁰ Functional outcomes of the wrist were shown to improve in both papers. However, only one paper found a statistically significant improvement. ⁹ One paper described a mean flexion–extension arc of 112 degrees and radial-ulnar arc of 40 degrees postoperatively, both had improved significantly. ⁹ The second paper described an active range of motion of 125 degrees postoperatively, it was significantly improved. ¹⁰ Both papers showed an increase in grip strength by 5 to 15.6 kg postsurgery. ^{9 10} Return to work was described in one paper and was moderate (64%). ⁹ Patient satisfaction was not evaluated.

Freedom

There are no papers that report on the clinical outcomes of the Freedom implant at the time of this study.

Discussion

The aim of this study was to establish the longevity and functionality of the fourth generation of wrist implants.

Compared with knee and hip implants, the longevity of previous generations of total wrist implants like the Universal 1, Biaxial, and Meuli is low, with an average 10-year implant survival rate of 40 to 83%. ² New designs of total wrist implants were developed to increase survival. These newer models were systematically reviewed in this study.

Implant survival analyses are defined by implant removal rates. This way, patients with residual pain or other complications while the implant was still in situ were not included in these analyses. Our data demonstrate an evident improvement in total wrist implant longevity compared with older generation models. Thirteen papers (76%) provided information on cumulated implant survival. The mean 5-year implant survival rate was higher than 92% and declined to a mean 78% at 15-year follow-up for the Universal 2 implant. The mean 8-year implant survival rate was 89% and is higher when compared with older models. The Motec wrist implant demonstrated the highest implant survival rate with a mean survival of 86% at 10 years and approaches the total hip (10-year survival rate 95.6%) and knee (10-year survival rate 96.1%) implants. ²⁶ All fourth-generation wrist implants resulted in a significant reduction of pain and improvement of wrist functionality as assessed by validated questionnaires.

Although this study strictly followed the PRISMA guidelines, it was limited by the low quality of many papers. After excluding 16 full-text papers due to small patient series, short follow-up, or double publications, only 18 papers were included in this review. Ten papers (59%) described prospective studies and compared pre- and postoperative results with validated questionnaires. However, none of the papers included control groups. Furthermore, the overall mean follow-up was only 5.5 years and long-term results (i.e., cumulated survival of 10 years or more) were only available for the Universal 2, ReMotion, and Motec total wrist implant. Consequently, no real recommendation as to which implant is to be preferred in terms of longevity can be given yet. However, overall mid-term results show very promising results in terms of survival. In this systematic review, we were not able to perform a subgroup analysis for rheumatoid and nonrheumatoid patients, due to the lack of subgroup outcome reporting and insufficient number of patients. The inconsistency in outcome measures is another limitation of this study.

Conclusion

A few conclusions concerning fourth generation total wrist implants are possible despite the methodological limitations of most of the included papers. First of all, wrist functionality is improved in terms of pain reduction and wrist mobility. Second, longevity of total wrist implants has evidently improved in the last decades. However, survival rates as seen in knee and hip implants are not yet reached. Further studies should focus on comparative, preferably randomized, trials with validated outcomes measured and long-term results are mandatory for determining the most effective TWA.

Funding Statement

Funding None.