9-Year Long-Term Results after Total Trapeziectomy with a Poly-L/D-Lactide Spacer Interposition Arthroplasty

Trapeziectomy generally results in satisfactory outcomes in stage IV Eaton-Glickel thumb base osteoarthritis.[1] However, first metacarpal subsidence can result in scaphometacarpal conflict and functional impairment.[2] Interposition with a poly-L/D-lactide scaffold (RegJoint) may prevent this. Short-term studies have shown pain reduction and improved function but concerns have been raised regarding osteolysis and secondary scaphometacarpal subsidence.[3] [4] [5] [6] [7] [8] [9]

Patients from the study by Van Royen et al were reassessed after 9 years.[3] The significance level was set at p < 0.05. Out of the initial nine patients (10 thumbs), five patients (6 thumbs) could be included. The mean age was 59 years (range 50–66 years). No significant differences were seen in grip strength, key pinch, or thumb range of motion compared with the contralateral hand at 1 or 9 years postoperatively. Mean pain score (VAS) decreased from 7.4 before surgery to 4.6 after 9 years of surgery. QuickDASH score initially improved significantly from 56 to 29 after 1 year but increased to 62 after 9 years ([Table 1]).

Table 1 Results

	Mean preop (SD)	Mean 1 year postop (SD)	P-value, year vs. preop	Mean 9 years postop (SD)	P-value, 9 years vs. preop	P-value, 9 years vs. year
Pain (VAS 0–10)	7.4 (1.7)	4.0 (3.0)	0.082	4.6 (2.3)	0.071	0.915
QuickDASH	55.8 (14.7)	28.2 (18.9)	0.032[a]	61.8 (16.0)	0.548	0.016[a]
	Mean non-operated side (SD)	Mean year postop (SD)	P-value, year vs. non-operated	Mean 9 years postop (SD)	P-value, 10 years vs. non-operated	P-value, 10 years vs. year
Opening of the first web space (°)	36 (29)	46 (17)	0.344	35 (26)	0.914	0.295
Opposition (0–10)	9 (0.6)	9 (1)	0.473	8 (1.8)	1	0.607
Retropulsion (0–3)	2 (1)	2 (1)	0.817	2 (1)	0.257	0.507
Grip strength (kg)	15.6 (5.2)	15.6 (4.9)	0.598	11.4 (3.8)	0.195	0.209
Key pinch (kg)	2.7 (1.8)	1.8 (1.5)	0.288	2.3 (1.6)	0.913	0.345
	Mean postop day 1 (SD)	Mean year postop (SD)	P-value, year vs. postop day 1	Mean 9 years postop (SD)	P-value, 9 years vs. postop day 1	P-value, 9 years vs. year
Scapho-metacarpal distance (mm)	9.0 (0.6)	4.2 (1.5)	0.009[a]	1.7 (0.8)	0.009[a]	0.019[a]

^a p-value < 0.05.

At 9 years, mean scaphometacarpal distance decreased significantly (1.7 mm) compared with immediate postoperative (9 mm) and 1-year postoperative (4.5 mm) ([Fig. 1]). Osteolysis was present in 50% of patients at 1 year but remained unchanged at 9 years ([Table 1]).

Fig. 1 Radiographic assessment with progressive decrease of the scaphometacarpal distance and osteolysis at the base of the metacarpal and distal articular surface of the scaphoid. (A) Preoperative radiograph. (B) Radiograph at 6-month postoperative. (C) Radiograph at 1-year postoperative. (D) Radiograph at 9-year postoperative. Double headed arrow, distance between first metacarpal and scaphoid.

Although the short-term results suggested improvements in pain and function, long-term outcome of the same cohort was less favorable with a significant increase in QuickDASH score. In our cohort, a double implant scaffold was inserted. In contrast, Bogaert et al advised to insert single scaffold to prevent increased pression on the articular surfaces.[8] Our practice of inserting a double implant may have influenced the outcome.

This study is limited by its small sample size and lack of control group. Further evidence is needed to determine whether scaffold interposition provides benefits over trapeziectomy with and without stabilization, like ligamentoplasty or suspensoplasty.

Contributors' Statement

K.V.R.: reviewing and editing; L.M.: data collecting and writing; C.K.G.: conceptualization, reviewing, and editing. All authors have met the ICMJE criteria for authorship.

Publication History

Received: 28 November 2025

Accepted: 07 January 2026

Article published online:
02 February 2026

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