The long-term outcome of simple trapeziectomy

Introduction

Simple trapeziectomy for trapeziometacarpal joint (TMJ) osteoarthritis (OA) was first described over 65 years ago (Gervis, 1949). Subsequent concerns have been raised that weakness of the thumb may occur as a result of shortening and degeneration at the scapho-metacarpal pseudo-arthrosis. Therefore, additional and alternative procedures have been proposed and are commonly used (Conolly et al., 1993). There is no strong evidence that these procedures, in addition to simple trapeziectomy, improve outcomes (Belcher and Nicholl, 2000; Catalano et al., 2008; Davis and Pace, 2009; Davis et al., 2004; De Smet et al., 2004; Field and Buchanan, 2007; Gangopadhyay et al., 2012; Gerwin et al., 1997; Kriegs-Au et al., 2004; Li et al., 2011; Martou et al., 2004; Shuler et al., 2008; Vermeulen et al., 2003; Wajon et al., 2005) and some have a higher incidence of complications than simple trapeziectomy (Davis and Pace, 2009; Wajon et al., 2005). Despite this, there is continuing controversy regarding the surgical management of basal thumb arthritis.

Studies commonly report short-term outcomes at 1 or 2 years after surgery. There are few studies reporting the long-term outcomes of simple trapeziectomy. The aim of this study was to investigate the long-term outcomes of simple trapeziectomy, carried out under the supervision of a single surgeon, in a large district general hand unit. The secondary aim was to compare the outcomes with the pre-operative function of an age- and gender-matched group of patients.

Methods

A retrospective study was done on a consecutive series of patients with primary TMJ OA who underwent simple trapeziectomy between January 2000 and December 2015. This primary procedure was performed by, or under the care of, the senior author (JEM) in a district general hospital serving a population of 360,000.

All patients had the same procedure in the same hospital and followed the same post-operative pathway. All patients included in the study consented to their participation. This study was classed as a simple audit and service evaluation. A routine, well-accepted surgical procedure was done in a standard fashion and with standard follow-up. There was no allocation or concealment of treatment. Patients were asked to complete a simple well-accepted questionnaire to assess their function and allow comparison of the outcomes on this cohort of patients with those reported elsewhere. It therefore did not fulfil the requirement for submission to the NHS Research Ethics Service.

The procedure was undertaken through a Wagner approach, with piecemeal removal of the trapezium and capsular repair. No Kirschner (K-) wire was used and ligament reconstruction and/or tendon interposition was not undertaken. Thumbs were immobilized in a splint for 6 weeks.

Two hundred and eighty-two simple trapeziectomies on 227 patients (mean age 66 years; age range 46–87 years) were done during this period. Twenty-three patients (26 trapeziectomies) had died at follow-up and 38 patients (51 trapeziectomies) were lost to follow-up. Therefore, 205 procedures in 166 patients were included. There were 20 (10%) men and 146 (90%) women. There were 106 (52%) left hands and 99 (48%) right hands. Thirty-nine (24%) patients underwent a subsequent contralateral procedure.

Patients were sent out the questionnaires to be completed and returned. A single follow-up phone call was made to those that did not return the completed forms. The questionnaire consisted of the shortened disabilities of the arm, shoulder and hand questionnaire (QuickDASH) and the EuroQoL five-dimensional questionnaire (EQ-5D) patient-reported outcome measures (PROMs) (Beaton et al., 2005; Brazier et al., 1993). The patient’s satisfaction with their operation at final follow-up was assessed using a 10-point Likert score which was converted to a simple percentage. A net promoter score (NPS) was completed by asking patients how likely it was that they would recommend the procedure to a friend or relative with the same condition. A 10-point Likert score ranging from ‘not at all’ to ‘definitely’ was used. The results were then categorized with scores of 0–6 being deemed as ‘Detractors’, 7–8 ‘Passives’ and 9–10 ‘Promoters’. Calculations were then done to produce a final score between −100, all Detractors, and +100, all Promoters. The mean follow-up period was 8.2 (range 3.5–17) years after the primary procedure.

The QuickDASH score is a reliable and validated tool which has been widely used in assessing outcomes of procedures for TMJ arthritis. It consists of 11 items, answered on 5-point Likert scales. The QuickDASH scores are calculated to give a score from 0 (no disability) to 100 (most severe disability). QuickDASH scores were divided into patient tertiles (low, intermediate and high) for our primary analysis and also used as a continuous variable (Beaton et al., 2005; Gummesson et al., 2006; Hudak et al., 1996; Wilkens et al., 2017).

The EQ-5D-5L is a standardized generic tool used to assess quality of life and provide Quality-adjusted life years (QALY) information about the effects of treatment (Brazier et al., 1993). It is based on five questions related to the patient’s level of depression/anxiety, self-care, base line activity, pain/discomfort and mobility. Each item has three possible levels of response (Brazier et al., 1993; Wolfe and Hawley, 1997). The EQ-5D is an index-based score that is interpreted along a continuum where 1 represents best possible health and 0 represents dead, with some health states being worse than dead (<0). The minimum clinically important difference (MCID) is reported to be 0.08 for UK patients (Pickard et al., 2007). In addition to the self-classifier, respondents rate their current health using a visual analogue scale that ranges from 0 (worst health state) to 100 (best health state) (Pickard et al., 2007).

As this was a retrospective study, no pre-operative scores were available for the trapeziectomy group. To allow assessment of difference in function before trapeziectomy, and at long-term review, a case-matched comparison was performed. Our institution now collects a prospective audit database of pre-operative PROMs in patients undergoing hand surgery. This database contained pre-operative scores for 39 patients who underwent simple trapeziectomy. Propensity score matching was used to match these pre-operative patients with cases from our long-term review group. Matching was undertaken based on age and gender. There was no statistical difference in the composition of the groups with regard to these variables (gender p = 0.425; age p = 0.466). Two to one matching was used therefore two post-operative cases were matched to each preoperative case.

Categorical variables (gender) were compared by Chi-squared tests. Differences between continuous variables were compared using Student t-tests (age, QuickDASH, EQ-5D). Correlation (i.e. between age and EQ-5D/QuickDASH) was investigated using the Pearson correlation coefficient. To determine effect size when comparing the pre-operative and post-operative groups, a z-score was calculated. This was the mean difference, divided by the standard deviation of the pre-operative score. Two-tailed tests were used and the level of statistical significant was set at p = 0.05.

Results

The mean QuickDASH score for the whole post-operative group (205 procedures on 166 patients) at final follow-up was 40 (range 0–89). The mean EQ-5D for the whole group at final follow-up was 0.46 (range -0.38 to 1).

There was no association between the QuickDASH, EQ-5D and gender (p = 0.109; p = 0.289 respectively). Additionally, no association between time from surgery and the QuickDASH or the EQ-5D (p = 0.642 and p = 0.998, respectively) was seen. The mean post-operative satisfaction score was 8.1 on a scale of 0–10, and the NPS was 71 (119 Promoters, 48 Detractors and 38 Passives)

Two thumbs (0.98%) underwent further surgery on the same thumb or TMJ during the study period. One patient had a metacarpophalangeal joint (MCPJ) fusion 1 year after the primary procedure after developing a symptomatic MCPJ that failed to respond to non-operative treatment. This patient had a QuickDASH score of 25 and an EQ5D of 0.65 at follow-up with an overall satisfaction of 80%. The second patient had a re-exploration of the TMJ joint, with excision of the proximal third of the trapezoid and reconstruction of the beak ligament with flexor carpi-radialis interposition, 2 years after the primary operation. This patient, despite further surgery, had a QuickDASH score of 86 and an EQ5D of 0.03.

Discussion

When non-operative treatment for TMJ OA fails, a small proportion of patients may require surgery. A variety of surgical techniques have been described over the years. In this large group of patients who underwent simple trapeziectomy, there was a sustained improvement in function and acceptable satisfaction at long-term follow-up. In comparison with the pre-operative group, the effect size suggested significant efficacy of treatment. The study demonstrated a good NPS of 71 which is similar to that of patients that have undergone a total hip replacement (Hamilton et al., 2014; Vermeulen et al., 2011). Overall, this study demonstrated that simple trapeziectomy alone offers good long-term function and satisfaction.

The mean QuickDASH score at final follow-up for all the post-operative patients included in this study was 40. A Norwegian study investigating normative QuickDASH values in the general population found scores increased with age and had a tendency to be higher in women (Aasheim and Finsen, 2014). They found female participants aged 70–79 years had a mean QuickDASH of 26 and those aged 80+ years had a mean score of 36. Additionally, scores may also be affected by other conditions, including those that affect the elbow and shoulder. It is therefore unrealistic to expect QuickDASH scores to improve to 0 especially when >90% of patients in this study were female and had a mean age of >74 years at final follow-up.

Many studies have supported the view that there may be no advantage to ligament reconstruction and tendon interposition (LRTI) over simple trapeziectomy and there is evidence to suggest complication rates may be higher with these adjuvant or alternative procedures (Belcher and Nicholl, 2000; Catalano et al., 2008; Davis et al., 2004; Davis and Pace, 2009; De Smet et al., 2004; Field and Buchanan., 2007; Gangopadhyay et al., 2012; Gerwin et al., 1997; Kriegs-Au et al., 2004; Shuler et al., 2008).

Despite the effectiveness of a simple trapeziectomy alone, surgeons have seemed reluctant to trust the track record of this procedure in providing patients with a good outcome. This was demonstrated by the study of Brunton and Wilgis (2010) that found only 3% of 1024 American surgeons would perform open trapeziectomy alone for advanced TMJ arthritis, compared with 68% who would perform trapeziectomy with LRTI. Seventy percent of the respondents had not changed their practice in 5 years despite many publications on this topic. More recent papers by Wolf and Delaronde (2012) and Yuan et al. (2017) report on this continuing trend among American surgeons to perform trapeziectomy with LRTI despite the evidence. The explanations for this surgical preference among surgeons in the United States included the paucity of previous studies to justify simple trapeziectomy alone, an entrenched rationale of preventing metacarpal instability, consumer demand and higher physician reimbursement rates associated with the additional LRTI compared with simple trapeziectomy (Yuan et al., 2017).

Several studies and reviews have suggested that additional randomized controlled trials (RCTs) and comparative studies would further clarify the best surgical procedure for this condition (Martou et al., 2004; Vermeulen et al., 2011; Yuan et al., 2017). The authors dispute the requirement for further RCTs to investigate this issue. The available evidence strongly supports simple trapeziectomy as being the most simple, safe and effective treatment, and this should be reflected in the consent process for simple trapeziectomy.

The main strength of this study is its size and the unique length of follow-up achieved compared with other studies. Another strength is that all the cases were treated in a single unit by, or under the direct care of, a single consultant orthopaedic hand surgeon. The main weakness of this study is the lack of pre-operative data. We sought to overcome this by reporting the outcome of large group of patients at long-term review, but also by a case-matched comparison with a contemporary pre-operative group. The use of propensity score matching from the current database is an attempt to overcome this weakness, and the data seen are in line with the pre-operative data from other trials. The technique and surgeon remained constant during this period. Second, there are data on only 78% of the surviving patients, but this is in line with most studies examining long-term outcomes. This study did not use radiographic review or face-to-face examination of function and strength. In order to maximize the number of patients, a questionnaire-based study design was chosen, which relied on patient reported functional outcome measures. This approach has been commonly used in recent large pragmatic studies, in which formal functional and radiographic assessment has been noted to offer little further benefit over PROM assessment alone.