Aim, design and setting
The study design is that of a single-blind prospective randomized comparison of two splinting methods for patients who have undergone zone II flexor tendon repair. The treating hand therapist and the patient would be aware of the treatment regimen but the assessing hand therapist (brought in for the 6 week and 12 week assessments) is specifically not aware of the splint used and remains ‘blinded’ to that information. The study is a single-center study that will inform development of a future multicenter study and is clinically based within the hand trauma service that serves a major conurbation and sees just under 4000 cases annually.
Characteristics of participants—recruitment to study
All patients who have sustained zone II flexor tendon injury and also meet the inclusion criteria of the study will be assessed by a Site Investigator (surgeon) for their potential suitability for the study and if appropriate will be invited to participate.
The detailed inclusion and exclusion criteria are presented in Table 1. These criteria include both patient factors and injury factors.
Processes, interventions and comparisons
The specific intervention is to test the use of a short splint against the traditional long forearm-based splint that we normally use for zone II flexor tendon repairs. Figure 1 illustrates the two splint designs with the traditional long dorsal splint (Fig.1A Dorsal view and Fig 1B lateral view) and the Short Splint (Fig. 1C Dorsal view and Fig 1D lateral view). The timelines, and assessments are detailed in SPIRIT Figure 2. This includes some modifications to the traditional exercise regime specifically to engage wrist movement and take advantage of the tenodesis phenomenon that passively increases interphalangeal joint extension. Detailed measurements are taken at 6 and 12 weeks into treatment in all patients by a ‘blinded’ therapist who is not party to which splint has been used (in all patients the splint is discontinued at 6 weeks). The frequency of visits to the hand therapy department is the same for both groups so there are no extra attendances as a result of participation in the trial.
The patients are counselled and invited to participate in the trial by a Site Investigator who is a member of the surgical team. The patient is provided with Patient Information Leaflet (Appendix 1). Recruitment only takes place at the first attendance to the hand therapy department when a therapist who is a Site Investigator goes through the counselling and consent for the trial and answers questions the patient may have. A Patient Consent Form is also completed at this time.
The surgery that is undertaken is by the standard protocol of the department and is not affected by this study. This protocol is for a 4-strand core suture using 3/0 prolene and a 5/0 epitendinous suture with adequate venting of the pulleys of the flexor tendon sheath. We are only concerned in this study with the aftercare.
It is normal practice to see the flexor tendon patients 4–5 days after surgery to commence rehabilitation. The patients in the study will have had this period of time to consider whether they wish to participate or not. If they choose to join the study then they are randomized at the first hand therapy visit by a hand therapist who is also one of the site investigators. The allocation model is of computer generated randomization sequence prepared at the start of the trial allocating patients into either Group A (Group A controls traditional splint) or Group B (Group B Manchester short splint). Patients who choose not to enter the study receive the traditional splint. Patients in both groups are treated by an experienced team of specialised hand therapists who will supervise their rehabilitation.
A patient who has initially given consent to participate but then loses capacity or chooses to withdraw consent to participate is withdrawn from the study. In practice this means that a patient in Group B (Manchester Short Splint) converts to traditional splinting any time within the first 6 weeks after operation. A patient on Group A (traditional splint) continues with that splint but does not undergo the specific assessments of the study.
Follow up arrangements are the same for each group and all patients are required to attend therapy clinic once each week for the first 6 weeks and undertake specified exercises. Following removal of the splint at 6 weeks, a program of exercise, soft tissue stretching and night splinting for residual contracture is initiated. Patients in both groups are permitted to return to normal activities at 12 weeks. From 6 weeks onwards once the splint is removed the treatment of all patients, regardless of Group is the same.
The rehabilitation protocol for both groups is that of early combined passive flexion and active motion exercises. The exercise sequence emphasises full passive flexion stretches to maximise passive digital motion prior to commencing active motion. Active flexion exercises is initiated from the distal interphalangeal (DIP) joint to maximise differential glide. Patients are encouraged to perform active flexion exercises carefully to minimise the work of flexion. They are encouraged to perform active digital extension exercises to minimise the occurrence of interphalangeal joint flexion contractures. Furthermore, patients are discouraged from performing excessive or forced active flexion at the end range of motion.
Patients in group A (traditional splint) perform digital flexion and extension exercises within the forearm-based splint keeping the wrist in a neutral and MCP joints at 30o flexion position. In contrast Patients in group B (Manchester short splint) perform active digital flexion exercises with the wrist extended to 45° and active digital extension exercises with the wrist in maximal flexion with the MCP joints at 30o flexion.
In both groups, volar thermoplastic finger splints will be provided for use at night in those patients who are unable to achieve full interphalangeal joint extension and therefore have incipient fixed flexion tendency notably of the PIPJs.
All patients will be given instructions on the safe and light functional use of their hands, excluding the injured digit(s). The patients will be instructed to wear their splints for a period of 6 weeks.
Assessment is undertaken at 6 weeks and on completion of treatment at 12 weeks by the ‘blinded’ hand therapist. The primary outcomes are the integrity of the tendon (presence or absence of tendon rupture) and range of motion of PIPJ and DIPJ of the affected finger and grip strength at 12 weeks only (grip strength at 6 week would risk tendon rupture). Secondary outcomes comprise Visual Analogue Scale for pain score, Quick DASH patient questionnaire, and the PEM questionnaire. The number and duration of visits to the hand therapy department is the same for both groups. The study duration is from the time the patient is first seen in the Hand Therapy clinic post-surgery and completes at 12 weeks for the patient.
Patients undergoing flexor tendon repair may potentially experience poor outcomes in terms of flexor tendon adhesions requiring flexor tenolysis or flexor tendon rupture requiring re-repair. In addition surgical wound infection can occur requiring surgical intervention to washout the flexor sheath. Need for such surgical interventions over and above the trial protocol will be recorded as adverse events within the Case Report Form and then the necessary surgery will take place as indicated. Additional surgeries may fall within the trial timeline, for example flexor tendon re-repair or after the monitoring period has concluded, for example flexor tenolysis. Patients affected in this way will still continue on the trial and have their data collected.
Table 2 details the assessments, investigations and interventions undertaken by the hand therapists with comparison on which parts of the pathway represent additional items that would not otherwise be part of routine treatment.
The assessment by the Site Investigator hand therapist includes:
- Quick DASH, PEM
- pain scales (Numerical Analogue Scale 0–10)
- range of motion of injured digit using digital goniometer
- grip strength and endurance power grip at 12 weeks using Jamar dynamometer on 2nd setting (power grip is not tested earlier to avoid potential tendon rupture)
The trials team will meet regularly to review conduct and progress of the trial and to ensure trial documentation is maintained in compliance with GCP requirements. The trials team will initiate and receive confirmation from the REC for trial amendments. Communication of approved changes will be communicated through the site investigators team by the Principal Investigator. This team will be scientifically independent from the sponsor. The responsibility for interim analyses and stopping guidelines will be with the trials team and Principal Investigator with advice from the trial statisticians.
Recruitment strategies will include regular educational updates for new members of the surgical team to act as Site Investigators. Our research nurse will assist with identification of potential participants based around the morning trauma meeting. The departmental trauma co-ordinator and trauma clinic nurses will also assist in case identification. In addition regular review of reasons for non-recruitment of potential patients will be undertaken. Retention of trial patients once on study is recognized to be important and this will be supported through the continuity of high level care in the hand therapy department.
Trial ethical approval has been obtained form the Research Ethics Committee 14/NW/1486 IRAS project ID 159054. The Research and Ethics Committee will send an independent reviewer to undertake a site visit to monitor trial conduct, compliance and documentation (approximately annually).
The Trust as sponsor is acting for ancillary and post-trial care as the need arises.
Statistical analysis and power calculation
Advice on statistical analysis was obtained from lead statistician Manchester University Foundation Hospitals Trust. On the basis of the observation from Peck et al 2014 (5) that there is a significantly reduced extension deficit at the PIP joint (median difference = 13 and mean difference = 10) and an increase in the total arc of flexion (median difference = 18 and mean difference = 12) for patients with the short splint compared to those with a traditional splint, then the advice is to recruit 60 patients (approx. 30 in each group). The outcomes in the original study (5) appear to follow close to a normal distribution such that a simple two-sample t-test should be used. The data set from the original study demonstrated SD of 21 and if it is assumed that that will be similar in the current study then the simple t-test will give a predicted power of 80% to detect the anticipated differences in anticipated improvements in pain and grip strength at the conventional 5% significance level.
The study protocol will comply with standard Caldicott and GDPR regulations. No names or dates of birth are used with respect to data entry to the study. Special patient identifier numbers will be generated for the Case Record Form (CRF) and used to identify patients through the study. Data collection is manual and this raw data is then transcribed into Excel held on Trust computer. The CRF hard copy files will be maintained on site consistent with regulations. The raw data transcription into electronic format will be undertaken by member of the hand therapy team. Primary data will be processed on Trust computers by the authors and secondary data transported without patient identifiers on encrypted pen drives. Processed data will be stored on home computers of the authors of the research study and will be the subject of peer review presentation and publication so will be communicated electronically at this stage.
Post study personal data will be stored for less than 12 months from the conclusion of the study (electronic and hard copy). Processed data will be stored in the Hand Therapy department files. Lead Hand Therapist (DB) will have access to the same and the processed data (electronic and hard copy) will be destroyed after 10 years. There are no specific plans to facilitate public access to the final trial dataset but this will be available on reasonable request from the Principal Investigator (VL).
Finally, publication of the results will be sought in peer-reviewed journal with presentation at national meetings. Summary of results will be communicated to participants by letter. The results will also be reviewed with our PI (patient involvement) group.