Outcomes of an exercise program in patients with dorsal or volar midcarpal laxity: a cohort study of 213 patients

Abstract

Purpose

Describing the outcomes of an exercise program on wrist and hand function for patients with midcarpal instability (MCI).

Materials and methods

This study has a prospective cohort design. Two hundred and thirteen patients with MCI were included. The intervention was a 3-month exercise program consisting of hand therapy and home exercises. The primary outcome was perceived wrist and hand function evaluated with the Patient-Rated Wrist/Hand Evaluation (PRWHE) three months after treatment onset. Secondary outcomes were conversion to surgery, pain, and satisfaction with treatment results.

Results

PRWHE total scores improved from 51 ± 19 (mean ± SD) to 33 ± 24 at 3 months (95% CI: 36–30, p < 0.001). All visual analog scales for pain demonstrated clinically relevant improvements at 6 weeks and 3 months (p < 0.001). At 3 months, 81% of the participants would undergo the treatment again. After a median follow-up of 2.8 years, 46 patients (22%) converted to surgery.

Conclusions

We found clinically relevant improvements in hand and wrist function and pain. Most participants would undergo treatment again and 78% of the participants did not convert to surgery. Hence, non-invasive treatment should be the primary treatment choice for patients with MCI.

IMPLICATIONS FOR REHABILITATION

• Midcarpal instability (MCI) is a disabling condition and treatment options are limited.

• Patients with MCI can benefit from an exercise program aiming to improve the strength and coordination of the wrist muscles.

• Participants improved in hand/wrist function and 78% did not convert to surgery.

• Non-invasive treatment should be the primary treatment choice for these patients.

Keywords:

• Hand
• wrist injuries
• conservative treatment
• surgical procedures
• physical therapy modalities

Introduction

Midcarpal instability (MCI) is a form of non-dissociative carpal instability. Injury or laxity of the extrinsic ligaments, bridging the proximal and distal carpal rows of the wrist, may result in abnormal carpal motion at the midcarpal joint [1]. Dorsal MCI and volar MCI are the most reported types of MCI caused by extrinsic ligament laxity [1]. During ulnar deviation, the proximal row stays in a flexed position until extreme ulnar deviation when the proximal row snaps back into an extended position [2]. As a result of the instability, patients with MCI often experience ulnar wrist pain, a typical “midcarpal clunk”, and limitations in hand function during daily activities and work [3–5].

Usually, treatment for patients with MCI starts noninvasively, including wrist immobilization, anti-inflammatory drugs (NSAIDs), corticosteroid injections, or exercise programs of the wrist [4–9]. Most exercise programs are based on a protocol by Videler et al. [10] focusing on the correct positioning of the wrist, muscle strength training, and functional stabilization during activities [3,7,8,11,12]. However, only one retrospective cohort study [9] investigated outcomes of this exercise program for patients with MCI and found promising results. This retrospective study did not investigate important outcomes such as conversion to invasive treatment. Although we found only one study with limited beneficial outcomes, exercise programs have a high potential. They aim for a more long-term solution than wrist immobilization, NSAIDs, or steroid injections and do not have the adversary effects of these treatments. Exercise programs have shown their usefulness as primary treatment in similar conditions such as atraumatic shoulder instability [13,14].

When noninvasive treatment does not provide sufficient results, invasive treatment can be considered. Several surgical methods related to soft tissue reconstruction have been proposed, such as dorsal wrist capsulodesis to increase midcarpal stability [15,16]. However, these surgeries come with longstanding rehabilitation and outcomes vary greatly [16,17].

Hence, more high-quality, prospective studies describing the outcomes of a non-invasive treatment for MCI are needed. Therefore, the primary aim of this study is to describe the outcomes of an exercise program for patients with MCI on wrist and hand function at three months after the start of treatment. Secondary outcomes include conversion to invasive treatment, pain, and treatment satisfaction.

Materials and methods

Study design and setting

This study is a prospective cohort study, reported following the Strengthening the Reporting of Observational Studies in Epidemiology statement [18].

Data were collected between December 2013 and August 2020 at Xpert Clinics Hand Therapy, comprising of 34 specialized outpatient treatment centers for hand surgery and therapy in the Netherlands. Data collection was part of usual care, using GemsTracker^a electronic data capture tools. GemsTracker (Generic Medical Survey Tracker) is a secure web-based application for distributing questionnaires and forms during clinical research and quality registrations. More details on our data collection are published elsewhere [19].

Participants have provided informed written consent. Since our study has an observational design, no clinical trial registration was needed. Our study followed the research ethics stated in the Declaration of Helsinki.

Participants

Patients were included when diagnosed with MCI by a hand surgeon based on medical history, anamnesis, location of symptoms (i.e., midcarpal pain), and thorough physical examination of the upper extremity, including a positive midcarpal shift test [15]. In some cases, patients were evaluated with radiographs, MRI, or other imaging to examine any structural abnormalities. This was not routinely performed and was left to the discretion of the hand surgeon, inherent to our observational setting. Patients were subsequently referred to a hand therapist. Follow-up with the hand surgeon took place 3 months after treatment onset to evaluate the treatment effect and to evaluate if invasive treatment was required. Patients were excluded when there were missing data, when they received a corticosteroid injection less than 6 weeks before the start of the treatment or had comorbidity or previous hand surgery interfering with the treatment or outcome (e.g., concomitant carpal tunnel syndrome or recent ganglion excision).

Treatment

Treatment was carried out by trained hand therapists who followed a standardized treatment protocol [7] that consisted of hand therapy sessions and home exercises (Supplementary Appendix 1). The treatment protocol is inspired by a protocol of Videler et al. [10] and is altered to fit the setting in which it was used in this study. The aims and rationale of this treatment protocol are explained in short below. The frequency of the appointments differed between patients, for example depending on treatment reimbursement or traveling distance. Therapy frequency was determined as a shared decision (range: two times per week to one time every two weeks). The next phase of treatment was started if the goals of the previous phase were reached.

In the first treatment phase (weeks 0–6), the program aimed at proprioceptive training and stabilizing the wrist in a neutral position during exercises and light daily activities. This neutral wrist position was defined by ±20° of dorsal flexion and the 3rd metacarpal aligned with the distal forearm (Supplementary Appendix 2). The exercises in this phase were mainly isometric and focused on static stability and increasing the strength of the extrinsic hand and wrist muscles, especially the midcarpal pronators, such as the m. extensor carpi ulnaris [11].

The goal for this treatment phase was for patients to be able to maintain the neutral wrist position with and without visual control. When patients were able to do so, treatment moved to the next phase.

In the second treatment phase (weeks 6–12), the goal for the patient was to stabilize the wrist during more complex and functional tasks. Exercises were added where the wrist stability of the patient was challenged with external factors such as weights, balls, or other objects (Supplementary Appendix 3). Furthermore, patients were encouraged to implement wrist positioning during more complex daily activities. Some patients with specific goals focusing on sports activities and occupations involving high strain on the wrist received treatment after 12 weeks. Treatment was ended when the specific goals were reached or no further improvements were to be expected.

Variables, data sources, and measurement

The baseline assessment for all relevant outcomes was done at referral to hand therapy.

The primary outcome of this study was perceived wrist and hand function at 3 months after the start of non-invasive treatment, measured with the Patient-Rated Wrist/Hand Evaluation (PRWHE; range, 0–100; higher scores indicate more pain and disability) at baseline and 3 months after the start of non-invasive treatment. The PRWHE has good reliability, responsiveness, and validity [20,21]. A minimal clinical detectable change (MCID) of 9.8 has been found in patients with MCI receiving conservative treatment [22].

The total score was the primary outcome and the subscales were secondary outcomes [21].

We gathered patient charts to examine conversion to surgery as a secondary outcome. The minimal follow-up period was 5 months after the start of the initial treatment, but some patients converted to surgery before 5 months, in which case that was the maximal follow-up duration for this study. The date and type of surgery were noted for every participant that converted to surgery.

We measured the average pain during the last week, pain during rest, and pain during physical loading as a secondary outcome with a Visual Analogue Scale (VAS; range, 0–100; higher scores indicate more pain) at baseline, 6 weeks, and 3 months after the start of non-invasive treatment. The VAS is valid, reliable, and appropriate to measure pain. The VAS has an MCID for average pain, pain during rest, and pain during physical loading of 13.5, 14.6, and 15.1, respectively, in patients with MCI receiving conservative treatment [22].

We measured satisfaction with treatment results at 3 months after the start of non-invasive treatment as a secondary outcome using the validated Satisfaction With Treatment Result Questionnaire [23], comprising two questions: “How satisfied are you with the treatment result so far?” (answering options: excellent/good/fair/moderate/poor) and “Would you undergo the treatment again?” (yes/no).

Demographical data, including duration of symptoms, type of work, second opinion, age, sex, dominant hand, and treatment side, were collected at baseline from the patient records.

Sample size

A sample size calculation for a repeated measures design showed that a total of 73 patients would be needed to identify a small effect size of 0.15 as defined by Cohen [24] for the primary outcome, with an alpha of 0.05 and a Power of 0.80. By including 213 patients, the statistical power of our study further increases.

Statistical analysis

The normality of the distribution of the primary outcome was assessed using distribution and normality plots. For the continuous variables with repeated measures, we used linear mixed model analyses with the outcome of interest as the dependent variable and timepoint as the independent fixed variable. To investigate the variability in the outcome of the PRWHE total score, we classified PRWHE in quartiles based on baseline score and ran subgroup analyses to investigate within-group time effects, again using linear mixed model analyses. Additionally, variability in outcome was investigated by plotting each individual patient course. We analyzed conversion to surgery using survival analysis.

Results

We screened 274 patients with MCI that had complete data for eligibility. Seventeen of these patients were excluded because they received a corticosteroid injection less than six weeks before the start of the treatment, 22 as they were incorrectly classified as an MCI diagnosis in our data, and another 22 had a previous injury or surgery that could potentially interfere with the current treatment potential (N = 22). Therefore, 213 patients were included in the study (Figure 1). The demographic characteristics of the participants are displayed in Table 1. The participants had a mean age of 31 (SD ± 11) years, 81% were female, and the mean duration of symptoms was 24 (SD 47) months. The demographic characteristics are in line with previous case studies and cohort studies [1,2,9] and with our clinical practice.

Figure 1. Flowchart of the study.

On the left are three boxes in blue with arrows in between them showing how patients were included in the study. On the right are two blue boxes explaining why patients were excluded from the study.

Table 1. Demographic characteristics of participants.

Variable	Demographic characteristics (N = 213)
Age, mean ± SD (years)	31 ± 11
Female (%)	172 (81)
Duration of symptoms mean ± SD (months)	24 ± 47
Treatment side (%)
Left	67 (31)
Right	132 (62)
Both	14 (7)
Dominance (%)
Left	18(8)
Right	187 (88)
Both	8 (4)
Type of work (%)
Unemployed	44 (21)
Light physical labor	63 (30)
Medium physical labor	81 (38)
Heavy physical labor	25 (12)
Second opinion (%)	17 (9)

SD: standard deviation.

During the treatment, 5% (n = 10) of the participants received a corticosteroid injection, and 3% (n = 6) received an arthroscopy for further diagnostics. These patients had persisting complaints and did not respond well to the treatment protocol. Most of these patients were suspected of having ligament lesions. For some patients, the reason was unknown due to the observation design of our study.

Effect on hand and wrist function

At 3 months after the start of non-invasive treatment, the PRWHE total score improved with a mean change of −18 (95% CI: −21 to −15, p < 0.001, Figure 2) compared to baseline. PRWHE subscales improved at 3 months with a mean change of −10 (95% CI: −12 to −8) for pain and −8 (95% CI −10 to −6) for function (Figure 2).

Figure 2. PRWHE total (range 0–100, lower scores represent better function) scores and PRWHE subscale scores for pain and function (range 0–50, lower scores represent less pain and more function, respectively) at baseline and 3 months. Improvements between baseline and 3 months were significant for all three scales (*). Group means with standard errors are plotted.

Three lines represent the mean PRWHE scores for the total score, the pain subscale, and the function subscale. The scores decrease over three months. Above the lines is another line with an asterisk indicating that these decreases are significant.

When investigating variability in outcomes in more detail, the course of individual PRWHE total scores demonstrated large variability in baseline PRWHE scores as well as in the changes after treatment (Figure 3(A)). However, subgroup analysis with quartile scores based on baseline PRWHE total score demonstrated improvement within all four quartiles, with a mean difference ranging from −8 to −28 (95% CI ranging from −4 to −35, Figure 3(B)).

Figure 3. (A) Individual change of PRWHE total scores (range 0–100; lower scores indicating better function) from intake to 3 months for a random sample (10%, n = 21) of the participants. (B) PRWHE (range 0–100, lower scores represent more function) scores over time categorized by quartiles based on the baseline total PRWHE score. Improvements between baseline and 3 months for all quartiles were significant. Group means with standard errors are plotted.

(A) Twenty-one lines representing the changes in PRWHE scores for individual patients over three months. Some lines increase, some stay level, and others increase their score. (B) Four lines decreasing over three months. Each line represents a quartile of the total study population based on their PRWHE baseline score; all these decreases are significant.

Conversion to surgery

After a median follow-up of 2.8 years (range, 0.1–7.7 years), 46 of the 213 participants (22%) converted to invasive treatment (Figure 4). The median time of conversion was 5 months (range, 1–35 months) after the non-invasive treatment onset. The most prevalent invasive treatment was directly targeted at the MCI and included a capsular procedure with or without a secondary treatment such as synovectomy, ganglion excision, or nerve denervation (37%, n = 17). The other invasive treatments seemed not directly targeted at the MCI, and included ganglion excision (33%, n = 15) or other invasive procedures (30%, n = 14) such as nerve denervations, tendon or extensor compartment releases, and CMC-1 stabilization; these procedures were not performed more than three times.

Figure 4. Survival curve displaying the number of patients who converted to surgery over time. The y-axis represents the fraction of patients not converting to surgery, and the x-axis represents the time in years after the onset of the exercise program. Twenty-two percent of the patients converted to surgery with a median conversion time of 5 months after the noninvasive treatment onset (range of conversion, 1–35 months). The shaded area around the line represents the 95% confidence interval. Vertical lines represent the end of the follow-up period.

One line represents how many participants did not convert to surgery. The line has a small horizontal line at the follow-up time when a patient is converted to surgery. Around the line is a colored area that represents the confidence interval.

Effect on experienced pain

We found significant improvements in VAS scores for pain during physical loading, mean pain during the last week, and pain during rest at 6 weeks and 3 months after the start of non-invasive treatment (Figure 5).

Figure 5. VAS (range 0–100, higher scores represent more pain) scores for pain during physical loading, average pain in the last week, and pain during rest at baseline, 6 weeks, and 3 months. Improvements between baseline and 6 weeks and between baseline and 3 months for all three VAS scores were significant (*). Group means with standard errors are plotted.

Three lines represent the three different VAS scores. All three lines indicate a decrease in VAS scores at six weeks and three months. One line with an asterisk above the lines spans from intake to the six weeks timepoint and indicates significant changes. One line with an asterisk above the lines spans from intake to the three months timepoint and shows significant changes.

Patient satisfaction with treatment

At 3 months after the start of non-invasive treatment, 81% of the participants would undergo the treatment again under similar circumstances, and 18% rated their satisfaction with the treatment result as excellent, 37% as good, 23% as fair, 15% as moderate, and 7% as poor (Figure 6).

Figure 6. Satisfaction with the results of the treatment of participants at 3 months.

Five bars represent how many patients had excellent, good, fair, moderate, or poor satisfaction with the treatment results. The bar representing good satisfaction with the treatment result is the highest, followed by fair, excellent, moderate, and finally, poor is the lowest bar.

Discussion

We found improved wrist and hand function in patients with MCI; the change score (–18) is higher than the reported MCID (9.8) and we, therefore, found a clinically relevant increase in wrist and hand function in patients with MCI. Only 46 participants (22%) converted to invasive treatment after a median follow-up of 2.8 years. Additionally, we found a clinically relevant decrease in pain and most patients were satisfied with their treatment and would undergo the treatment again.

The treatment in the present study is based on the principle that increasing muscular strength and coordination can compensate for the effects of lax ligaments, namely pain and decreased wrist and hand function [3,11]. To our knowledge, only one study evaluated a similar program [9]. They found a decrease in pain from 8 points before treatment to 4 points after treatment measured with a VAS scale (range 0–10). This is a larger effect compared to the present study. However, data were gathered at a median duration of 6 years after the treatment in their study, allowing for recall bias. In addition, wrist and hand function was only measured after the treatment and no data were collected about the hand/wrist function of the participants before treatment. This makes it impossible to show adequate associations between the treatment and hand/wrist function. Furthermore, the present study included more participants (213 compared to 119), adding more power. Since the data in our study were gathered prospectively at baseline, 6 weeks, and 3 months after treatment onset, there is no risk of recall bias present.

Most MCI patients experience severe and chronic hand function impairment [3,4]. The usual non-invasive treatment options mainly consist of activity modification to avoid pain and splints to restrict painful motions [3,5]. Invasive treatment options are scarcely described, and outcomes vary greatly [16,17]. As a result, patients with MCI still have impaired hand function after treatment or depend on their splint to have a good hand function. Our exercise program increases hand function and decreases pain without patients depending on their splint. Adding to this, only 22% of the participants converted to invasive treatment, of which 33% was a ganglion excision procedure. It should be noted that patients may be instructed to keep training themselves after the 3 months of the exercise treatment to maintain and optimize the stability and strength of their hand and wrist, although future research should investigate how this should be employed.

When looking in detail at the improvement in hand/wrist function, all quartiles based on baseline symptom severity significantly improved. However, patients with relatively little impairment at baseline (quartile 1) showed less improvement compared to patients with more impairment at baseline (quartile 4). An explanation for this difference could be, that patients with fewer impairment have little space for improvement. The clinical implication of this finding is that patients that present with more severe impairment can expect a larger and more noticeable improvement than other patients, although, in general, they can also expect more residual symptoms. This knowledge can be used in managing patient expectations.

After a median follow-up period of 2.8 years, 46 patients (22%) converted to surgery. A large variety of surgical procedures were performed. Only 37% (n = 17) of the patients had a surgery directly targeting the MCI; namely a procedure aiming to improve the passive midcarpal stability. The other participants received procedures indicated for conditions that may be related to MCI, such as ganglions and capsular or tendon inflammations. This suggests that in some cases, MCI is present in combination with other hand or wrist pathology, which could explain why these participants converted to surgery.

This study has an observational design without a control group. Thus, this study does not provide conclusive evidence on the causality of the treatment effects we found. We cannot be certain that the treatment can partially or fully explain the found outcomes, which is inherent to our observation design and the fact that no control group was included. Another limitation of the observational design is that variations from the treatment and measurement protocols may have occurred. Although the treatment and measurements are carried out by trained therapists using standardized protocols, this may have introduced bias. Similarly, we did not monitor compliance with the exercise program and analyzed our data using intention-to-treat principles, making it unclear whether every patient followed the full exercise program. Finally, because we did not use a strict diagnosis algorithm inherent to our study design, the diagnostic process leaves some room for uncertainty. On the other hand, our observational design has great ecological validity, and the promising and clinically relevant improvements we found substantiate the need for a randomized controlled trial to validate our findings. Another strength of our study is that it is, to our knowledge, the first prospective study reporting the outcomes and conversion to surgery of an exercise program for patients with MCI. Additionally, a large sample size was reached in the study, and outcomes were evaluated with validated patient-reported outcome measures.

Not all patients improved in pain and hand and wrist function. Figure 3 shows large variability in function levels before and after treatment and some patients even decrease in function. Hence, future studies should investigate potential factors explaining variation in treatment outcomes, such as factors predicting a higher odds of converting to surgical treatment. Furthermore, the long-lasting effects of this non-invasive treatment should be investigated with the use of a 1 year follow-up period.

Conclusions

In conclusion, a 3-month exercise program consisting of hand therapy and home exercises leads to clinically relevant improvement of hand and wrist function and a clinically relevant decrease in pain in patients with MCI. Importantly, only 22% of the participants converted to surgery within 3 years, of which 63% was not directly to improve midcarpal stability. Therefore, we believe that this shows the benefits for patients with MCI of initial non-invasive treatment with an exercise program similar to our described program.

Ethical approval

This study does not require approval of the ethical committee in our country (The Netherlands).

Disclosure statement

Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.