Patients with an injury in flexor digitorum profundus (FDP) are eligible for inclusion in this study. The patients are referred to the Department of Hand Surgery at Sahlgrenska University Hospital. Potential patients are informed about the study. An informed consent is obtained from those who accept to participate. The surgery is performed in the same way for all patients with a four-stranded core suture and an epitendinous suture. The randomisation is performed after surgery when the patient is starting up rehabilitation 1-3 days after surgery. The randomisation was done by a computer program and the two different mobilisation protocols are placed accordingly in sealed envelopes numbered from 1 to 64. The envelopes are used one after another in a consecutive order.
All the operations are done by specialists in hand surgery or experienced residents in hand surgery at the clinic. The FDP tendon is repaired with a four-stranded core suture with a 4-0 Ti-cron (nonabsorbable braided polyester) and a running epitendinous suture according to Silfverskiöld with a 6-0 Prolene (nonabsorbable monofil polypropylene). Any concomitant injury in the flexor digitorum superficialis (FDS) tendon is repaired according to the surgeons preference. Any digital nerve is repaired with microsurgical instruments and a 8-0 or 9-0 S\&T (non-absorbable polyamide monofilament).
Mobilisation
1-3 days after surgery the patient will be randomised to either active mobilisation or passive mobilisation with rubber bands and active place-and-hold at the hand rehabilitation unit in our clinic. The patients in both groups are closely followed by an occupational therapist for 12 weeks. Additional follow-up appointments are planned after 6 and 12 months. Patients in both groups are allowed to do all kinds of normal activity after 3 months and heavy manual work and gym training after 4 months.
Active mobilisation The active mobilisation program is based on the two programs, Belfast (ref) and Billericay (ref). Our program is a mix between these two. On the first day of mobilisation (1-3 days after surgery) the dressings are changed and a dorsal splint with the wrist in neutral position and the metacarpophalangeal (MCP) joints in 60-80 degrees of flexion is made for the patient. Another removable volar plate keeping the fingers extended is used in addition to the dorsal splint between training sessions.
The patient is instructed to flex the fingers passively with the other hand and then keep the fingers in flexion and do the place and hold for 3 seconds. Then the fingers are extended actively as far as the splint allows. This motion is done with 5 repetitions, 10 times per day with 1.5 hour resting period between sessions. Every second training session (i.e. every third hour) all fingers are flexed actively three times. After a week both the passive motion with place-and-hold and the true active motion is done with 10 repetitions, 10 times per day with a resting time of 1.5 hours between training sessions. Four weeks post surgery flexion and extension of the wrist is added with 10 repetitions, 4 times per day and joint-by-joint training for the injured finger with 3 repetitions 10 times per day in addition to the previous protocol.
Passive mobilisation with place-and-hold Before the mobilisation starts the patients get their dressings changed and a new dorsal forearm plaster ending at the level of the proximal interphalangeal (PIP) joints with the wrist in neutral position and a dorsal block over the proximal phalanges creating an extension block for the MCP-joints of 60-80 degrees. Rubberbands are attached to all the fingernails and a small hook is fastened to the plaster to hang the rubberbands on creating a resting position for the fingers between training sessions. A night splint with the interphalangeal joints in extension is also made to protect the fingers and keep them in full extension when the patient sleeps.
The patient is instructed to flex the fingers passively with the other hand one at a time and then keep the fingers in flexion and do a gentle squeeze, so called place-and-hold. Then the fingers are extended actively as far as the plaster allows. For four weeks the patient do this exercise with 10 repetitions, 10 times a day (7-8 repetitions on the first day) with a resting period of 1.5 hours between sessions. After four weeks the plaster is removed and replaced by a splint protecting the wrist in neutral position and the patient adds true active flexion of the fingers to the previous program with 10 repetitions 10 times per day. Six weeks post surgery the splint is removed and flexion and extension of the wrist is initiated.
