Abstract
The aim of this study was to assess the clinical and radiological results of the Rubis II thumb carpometacarpal joint reverse prosthesis, at a mean follow-up of 10 years.
Between 1997 and 2008, 253 prostheses were implanted in 199 patients; 115 were reviewed. The survival after a mean of 10 years was 89%. At the last follow-up, 70% of prostheses were painless; the others reported moderate or intermittent pain. The satisfaction rate was 98%. The mean opposition was 9 on the Kapandji scale; the mean QuickDASH score was 30. Wrist, key and tip pinch strengths were comparable with the non-operated side. Of the 115 implants, one was radiologically loose (1%) and 15 had suffered dislocations (13%), 12 of which were caused by an injury. Eleven thumbs had revision surgery.
This study confirms that the good clinical results of the Rubis II prosthesis are maintained in the medium and long term, and represents a useful alternative to trapeziectomy for selected patients.
Keywords
Introduction
When medical treatment of osteoarthritis (OA) has failed, the main surgical treatment is trapeziectomy with or without ligamentoplasty (Eaton and Littler et al., 1973; Vermeulen et al., 2014; Vermeulen et al., 2011; Weilby, 1988). Although several studies have shown good results with thumb carpometacarpal (CMC) joint OA (Apard and Saint-Cast, 2007; Chug et al., 2014; Corcella et al., 2014; Seng and Chantelot, 2013), no study has yet demonstrated the superiority of one technique over the other (Huang et al., 2015).
In our experience, the Rubis II implant gives good short- and medium-term results (Laterza-Leroy et al., 2011; Maes et al., 2010). There are no reports of the long-term outcomes of these implants.
The aim of this retrospective review of a series of 253 Rubis II prostheses was to assess the clinical and radiological results at a mean follow-up of 10 years.
Material and methods
Patients
Between January 1997 and December 2008, 253 Rubis II prostheses were implanted by four surgeons in 199 patients in Saint-Quentin – Aisne public hospital (France). A total of 95 patients (115 implants) were reviewed; 11 implants (11 patients) were explanted and excluded from the final analysis. A total of 84 patients (104 implants) were reviewed at a mean follow-up of 10 years (range 6–17). A total of 11 patients (13 implants) had died; 67 patients (97 implants) were lost to follow-up; seven refused to be reviewed (7 implants); 19 patients (21 implants) were interviewed by phone (flowchart, Figure 1).
Flowchart.
The 115 arthroplasties were performed by four surgeons; 64% were operated on by one of the authors (MM). The other surgeons operated on 31%, 4% and 1% of thumbs. The inclusion criteria were painful thumb OA following failure of medical treatment and responsible for disability in activities of daily living, which had been operated with a Rubis II CMC reverse implant. The exclusion criteria were patients operated with a Rubis II non-reverse implant, or for whom a trapeziectomy had been performed. The two main surgeons considered that manual workers constituted a contraindication, although this was not a strict rule. When patients suffered clinical and radiographic scapho–trapezo–trapezoidal OA, all surgeons preferred trapeziectomy or in a few cases sandwich arthroplasty (concomitant carpometacarpal (CM) and scapho–trapezo–trapezoidal arthroplasty). These patients were not studied.
Prosthesis
The Rubis II is an unconstrained metal-on-metal reverse total prosthesis made of chromium–cobalt–molybdenum alloy (ISO 5832-4 compliant) and coated with pure microporous titanium by plasma torch. The metacarpal implant consists of an anatomical stem designed to preserve bone stock with a triangular section allowing antirotation stability. The neck is offset from the stem, reproducing normal anatomy, and is designed to improve stability, as the reverse design theoretically decreases the risk of dislocation, while allowing a 55° range of motion in all directions.
The trapezial implant consists of a screwed circular plate, designed to avoid sinking of the implant in the cancellous bone (Dunaud et al., 2001).
Surgical technique
All prostheses were implanted according to the operative technique described by Dunaud et al. (2001) via a posterolateral incision.
Post-operatively the patients remained in hospital for two nights; they remained in a thumb was splinted for 3 weeks, when they were reviewed with up-to-date radiographs, followed by self-rehabilitation. No physiotherapy was prescribed unless specifically required by the patient.
Patients were reviewed clinically and radiographically by two independent reviewers (MD, MC). Each patient had both thumbs examined according to a standardized protocol. The objective criteria were: scar (dystrophia, dysesthesia or hypoesthesia); ranges of motion (thumb CMC joint retropulsion, abduction, metacarpophalangeal and interphalangeal joint flexion and extension) were measured with a handheld goniometer and combined movement using the Kapandji method; grip strength with a Jamar© dynamometer at position II; and tip and key-pinch strengths with a Preston© dynamometer. The strengths were compared with the other thumb if it had not been operated on, whether this thumb was symptomatic or not. The subjective criteria were: pain measured by a visual analogue scale (VAS); the French version of the Quick Disabilities of the Arm Shoulder and Hand score (Kennedy et al., 2013) (Quick DASH) (Dubert et al., 2001); and a global satisfaction scale (unsatisfied, disappointed, satisfied or very satisfied). Times to return to work and leisure activities were also recorded.
The radiological assessment was performed on standard orthogonal radiographs (Kapandji’s views) (Kapandji et al., 1980) of the operated thumb. The pre-operative radiographs were graded using the Dell classification (Dell et al., 1978) (Table 1). Post-operative radiographs were examined for the presence of radiolucent lines, loosening (Pendse et al., 2009) and periprosthetic ossification.
Dell classification of OA (1978).
Survival was calculated from the 115 prostheses implanted; implants that had not been removed were considered to be survivors. The study protocol was approved by the Amiens – Picardie (France) University Hospital ethics committee.
Data were collected and analysed with Easy Med Stat software (www.easymedstat.com; Neuilly-Sur-Seine, France). The Kaplan–Meier method was used to measure survival.
Results
The survival after a mean of 10 years was 89% (Figure 2).
Prosthesis survival.
Out of the 115 thumbs, 11 (10%) were reoperated for explantation. The reasons for these 11 explantations were recurrent prosthetic dislocations for five, loosening for four implants, metal allergy for one (confirmed by skin tests) and trapezium fracture for one.
These prostheses were replaced by Ascencion or CMI pyrocarbon metacarpal stems in seven thumbs. Three patients had a trapezectomy after implant removal and one patient had the same procedure with ligament suspension with the abductor pollicis longus tendon. For these 11 thumbs, the mean Quick DASH was 30, the mean opposition was 9 on the Kapandji scale and key-pinch strength was 62% of contralateral side and tip-pinch strength 69% (Table 2).
Outcome after a mean follow-up of 10 years (all patients) and ⩾ 15 years.
SD: standard deviation; VAS: visual analogue scale.
Of the 84 other patients with remaining implants, there were 78 women and six men with a mean age at operation of 61 years (range 45–82). A total of 65 prostheses were implanted in retired patients (62%). The left hand was treated in 60%. According to Dell’s classification (Dell et al., 1978), the OA was Stage III in 52 (50%) cases, Stage II in 49 (47%) cases and Stage IV in 3 (3%) thumbs (Table 1).
Of the 104 hands, 102 had adequate thumb retropulsion that could be placed flat on the examination table (98%). The mean Kapandji score was 9/10. The metacarpophalangeal joint range of motion was 55° (range 20°–105°) (Table 3).
Mean range of motion at 10 years follow-up.
The mean grip strength was 180 N; 92% of the strength of the contralateral non-operated wrist. Mean key pinch strength was 98% of the opposite side and mean tip pinch strength was 92% (Table 2).
A total of 73 thumbs were completely painless at last review (70%). Among the 31 patients reporting pain, the mean VAS score was 1 at rest and 5 during activities. The mean Quick DASH score was 30.
The patients were satisfied or very satisfied with the outcomes of 103 out of 104 thumbs (99%). The only dissatisfied patient was a woman who required surgical revision to change her metacarpal implant after 12 years. Out of 104 patients, 99 (95%) reported that they would be willing to undergo the procedure again if necessary.
Seven of the patients were manual workers (two were male farmers and five were cleaning ladies); all were able to return to work. The mean time off work for the 42 working patients was 10 weeks (range 1–52). Ten patients did not return to work or changed jobs. Seven of them were near to retirement and did not return to work for this reason; three patients did not return to work due to complications: Type 1 complex regional pain syndrome (CRPS I) in one patient; a major loss of strength in one; and apprehension about using their thumb at work in one.
Most (70%) patients undertook one of the following leisure activities: gardening, do-it-yourself, sewing or knitting. All but five of the patients resumed their pre-operative leisure activities.
The main complication was dislocation: 15 prostheses (13%) dislocated after a mean interval of 2 years (range 12 days–6 years) (Figure 3). The mean number of dislocations per patient was 2 (median 2; range 1–5). The dislocations followed an injury, for example a fall onto the outstretched hand in 12 cases, or an unusual movement, for example operating a jackhammer or turning a key stuck in a door in two cases; one patient woke up with a spontaneous dislocation.
Prosthetic dislocation.
Four of the patients remained stable after closed reduction of their implant. Five patients underwent revision surgery. In four cases, the metacarpal implant was changed for a longer stem and in one case the trapezial component was realigned. One patient had a permanent dislocation that was well tolerated and so left. The five other implants were explanted.
Periprosthetic radiolucent lines ⩽1 mm that remained stable over time and affecting less than 50% of the implant–bone interface (similar to types A or B of Pendse with cemented prostheses) were seen in 14 (13%) implants. Periprosthetic ossification were seen in 28 thumbs (27%) (Figure 4). Scar complications were uncommon (6%). One scar was painful when touched, two were markedly adherent to the subcutaneous tissues and three patients suffered from hypoesthesia around the scar. Only the painful scar was appreciably intrusive. All other non-pain patients had radiographs with no special features (figure 5).
Heterotopic ossification. Pain-free patient.
Pain-free patient at 12-year follow-up.
Discussion
The long-term outcome of the Rubis II thumb CMC joint arthroplasty seems reasonable. Pain was reasonably reliably resolved. The ranges of motion were satisfactory, similar to those reported with other implants (Brutus and Kinnen, 2004; Chakrabarti et al., 1997; Jacoulet, 2005). Reasonable strength was achieved for most patients, which is not the case for all prostheses (Seng and Chantelot, 2013). Reported quality of life improved. The discordance between a high Quick DASH score and the improvement of quality of life was frequently due to associated shoulder or wrist pathologies.
The long-term survival of the implant is one of the highest rates reported for thumb CMC joint prostheses with a 10-year survival of 89%. Other authors have reported 5-year survivals of 77% to 90% (Apard and Saint-Cast, 2007; Chakrabarti et al., 1997; Nicholas and Calderwood, 1992; Van Cappelle et al., 1999) and 10-year survivals of 90% to 94% (Huang et al., 2015; Krukhaug et al., 2014; Martin-Ferrero, 2014; Semere et al., 2015). In addition, patients followed for 15 years or more continued to have good clinical outcomes, similar to those of the overall series.
Some patients experienced residual, but generally moderate and intermittent pain, which may be due to pain in adjacent arthritic joints. Other authors, such as De Smet et al. (2004) and Brutus and Kinnen (2004) have also noted poorer results in patients with concomitant neighbouring OA.
The main complication in our series was dislocation. Although this complication was not unusual in other series, our dislocation rate of 13% was high compared with the literature, as other authors have reported dislocation rates of 0% to 9.5% with a mean follow-up of 15 to 126 months (Brutus and Kinnen, 2004; Martin-Ferrero, 2014; Seng and Chantelot, 2013; Wachtl and Sennwald, 1996). A total of 93% of dislocations occurred after trauma, abnormal movements or overuse. Candidates for arthroplasty should be cautioned about high-risk activities.
According to Wachtl et al. (1997), trapezial loosening of trapezometacarpal (TM) arthroplasties can be explained by medialization of the metacarpal axis of these straight metacarpal stems, responsible for increased shear stress on the trapezial cup. The offset neck of Rubis II preserves metacarpal lateralization, as observed in Dell Stage II and higher OA. Shear stress is, in theory, reduced in moving into opposition.
Radiolucent lines ⩽1 mm, without obvious implant loosening, which remained stable were frequent in our series, as in previous studies (Laterza-Leroy et al., 2011; Maes et al., 2010), and as reported by other authors with other implants (Chakrabarti et al., 1997; Lemoine et al., 2009; Seng and Chantelot, 2013).
Trapeziectomy with or without ligamentoplasty, has been for a long time and still is, the gold standard technique for treating symptomatic thumb CMC joint OA (Eaton and Littler,1973; Vermeulen et al., 2011, 2014; Weilby,1988). But there are complications and unsatisfactory results (Rhee and Shin, 2014). In a recent Cochrane meta-analysis (Wajon et al., 2015) including 11 randomized controlled trials with 670 participants, seven surgical procedures were identified, among which was trapeziectomy; there were no differences regarding pain or function in the only study (Tägil and Kopylov, 2002) comparing trapeziectomy with an arthroplasty (Swanson). There were no comparative studies reporting on total arthroplasties of the thumb CMC joint.
Few series of long-term follow-up of Thumb CMC joint arthroplasties have been published, and generally comprised smaller numbers of patients (Chakrabarti et al., 1997; De Smet et al., 2004; Huang et al., 2015; Krukhaug et al., 2014; Van Cappelle et al., 1999). The only other long-term (mean 12 years) review of the Rubis II implant reviewed 20 patients (Laterza-Leroy et al., 2011).
There are limitations of this study, in particular: it is a retrospective study; a large number of patients were lost to follow-up despite our efforts to contact them; and there is no established subjective scoring system for the thumb that we could use.
In conclusion, this study confirms that the good early clinical results of the Rubis II prosthesis are maintained in the medium and long term. We believe this represents a useful alternative to trapeziectomy for selected patients. The main complication of this implant was dislocation, although no specific risk factor for dislocation was identified.
Footnotes
Acknowledgements
Eric Havet, MD PhD, who served as scientific advisor with kindness.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethical approval
Patients were informed orally and in writing, and written consent was obtained before the consultation. The study protocol was approved by the CHU Amiens – Picardie (France) ethics committee.