Flexor tendon repair : rehabilitation adherence, outcome and complications

Abstract: Flexor tendon injuries in the finger (zones 1 and 2) are problematic due to high rates of both rupture of the repair and of soft tissue adhesions resulting in poor range of motion. Both complications often result in reoperations and worse outcome of the injury. Rehabilitation after flexor tendon repair is a balancing act for the patient. The exercise and daily activities of the hand need to be at enough force to avoid soft tissue adhesion forming which restrict finger motion but still with low enough force to avoid rupture of the repaired tendon. This creates high demands on patient’s adherence while coping with the injury in everyday life. The literature describes the importance of adherence but, there is little evidence in terms of how to improve and understand patient adherence to flexor tendon rehabilitation. Risk factors for the two most common reasons for reoperations have been studied but there is a lack of studies including detailed variables about the repair, the injury and the patient. The outcome after flexor tendon repair is often reported as a classification into a category; poor, fair, good or excellent based on the finger range of motion. This classification could be criticized as being too simplistic for a complex injury, but still there is little known about how the patients´ perceptions of their outcome corresponds to these classifications. The overall aim of this thesis was to improve and explore rehabilitation adherence and outcome, including a smartphone intervention and patients´ perspectives, and to explore complications after flexor tendon repair and rehabilitation. In paper 1, a total of 101 patients were included at the start of early active motion rehabilitation after their flexor tendon repair. Patient were randomised to rehabilitation with the aid of a smartphone application or according to standard rehabilitation. Patients adherence, self-efficacy and range of motion were then assessed at baseline, and two, six and 12 weeks after repair. There were no overall differences between the groups in range of motion, adherence, or self-efficacy. In paper 2, Seventeen patients with flexor tendon repairs were interviewed after three months of early active motion rehabilitation. The interviews were then transcribed and analysed according to deductive content analysis based on the health belief theory. The results are described in six categories: perceived susceptibility to loss of hand function; perceived severity of the injury; perceived relationship between cost, benefits and efficacy of rehabilitation; perceived self-efficacy; relationship between patient and practitioner; and external factors. In paper 3 data was collected from the Swedish national hand surgery registry (HAKIR) and Statistics Sweden (SCB) on a cohort of patients with flexor tendon repair between 2010 and 2019. A total of 1375 patients were identified and followed for at least one year to assess reoperation due to rupture or tenolysis. The result showed that 5% of patients had been reoperated due to rupture and 4.8% due to tenolysis. There was an increased risk of rupture in male patient, age above 25 and in patients where the FPL tendon had been repaired. If both the FDP and FDS tendons were repaired, it increased the risk for both tenolysis and rupture. With increasing income, the frequency of tenolysis increased. In paper 4 we collected data from HAKIR on patient with flexor tendon repair between 2010 and 2020. We then used data on patients with a complete set of data from the patient questionnaires and functional assessments of range of motion at three and 12 months after repair. The patient questionnaire included the HQ-8, Quick-DASH and perceived satisfaction with results. We assessed 215 patients at three months after repair, and 150 patients at 12 months. We calculated the association between patient reported outcome and the Original Strickland classification. As perceived stiffness increased the OR of being in a higher Strickland level decreased, although perceived stiffness could only discriminate between the independent levels of fair and good. An increased Quick-DASH score decreased the OR of being in a higher Strickland level, although only between fair and poor results at three months. As perceived satisfaction with result increased, the OR of being in a higher Strickland level also increased. But perceived satisfaction could only discriminate between the levels of fair and good at twelve months. In conclusion, the smartphone application did not increase the adherence, self-efficacy or range of motion during the first three months of rehabilitation. Patients’ perceptions of the injury, the rehabilitation, and the context and support during rehabilitation affects adherence. Several risk factors were associated with reoperation due to rupture or tenolysis, namely male sex, age above 25, injury to FPL or both FDP and FDS. Patient-reported outcome only corresponded with some independent levels of Strickland and the classification of range of motion into poor, fair, good and excellent may thus add little value to the patients. Understanding the risk factors, the constructs related to adherence and patient-reported outcome may give important knowledge to surgeons and therapists when treating patients with flexor tendon injuries.