Description of Intervention
Extensor tendon injury frequently accompanies complex injury with adjacent tissue involvement i.e., fracture, crush, revascularization, replantation, burn, rheumatic disease. Describing management of the extensor tendon component of these multi-tissue system diagnoses is beyond the scope of this chapter. The intent herein will focus upon management of tendon discontinuity only, generally via sharp or blunt trauma.
Extensor tendon rehabilitation restoration seeks to restore optimal hand AROM. This is a complex endeavor. Effective management requires appreciation of the biomechanics of the hand based on a knowledge of the intricate anatomy and balance of structures. The extensor system, with its 9 separate zones necessitates clinical problem solving for management of injury at each zone.
Our current interventions with post-surgical management of tendon injury involve, as always, an understanding of tissue/wound healing. In particular, the therapist must appreciate the rate of tendon healing in the context of each patient,1 of each surgeon’s technique and of each zone. While in times past, clinicians employed weeks of immobilization to ensure tendon continuity, we now use our understanding of these multiple factors to stage strategic mobilization. Understanding that 3-5 millimeters of tendon glide (also sometimes called Short-Arc-Motion or SAM2 can minimize tendon adhesion formation if performed regularly and can, ultimately, optimize outcomes.
Therapist management includes:
Pain Management
- Edema management
- Wound management
- Application/fabrication of specific and often sequential orthoses
- Strategic instruction in exercise/activity to appropriate to healing stage to optimize tendon glide and joint ROM while protecting the healing tendon
- Identification of ADL challenges and provision of short-term adaptations
Therapists must guide their patients to maintain all safely possible PROM of joints adjacent to the injury / repair to minimize unnecessary stiffness of technically uninvolved fingers. The interconnections between the extensor tendons to multiple fingers can make this endeavor challenging.
Indications for Intervention
Any disruption of extensor tendon continuity will require intervention.
Evaluation to Determine Need for Intervention
Generally, the physician referral determines the need for intervention. ROM and pain assessment may also reveal a previously undiagnosed extensor tendon continuity issue.
Intervention Options
The zone of injury determines intervention options as well as whether the treating provider opted for conservative or surgical management. As stated above, clinicians have employed either immobilization or mobilization treatment approaches or a combination of the two.
REVIEW OF THERAPIST CONSERVATIVE INTERVENTIONS FOR MALLET FINGER (ZONE I & II EXTENSOR TENDON INJURY)
The hand surgery and therapy literature has long identified mallet finger (closed, zone I and II extensor injury) as a tendon injury that can result in complete or near complete resolution with a skilled non-surgical approach. The key to post injury management involves coapting the edges of the injured tissue — either the avulsed tendon or the bone surfaces. Therapy guidelines for the non-operative patient have changed over the past years. The 6-week regimen of DIP orthosis immobilization in extension or slight hyperextension has long stood in the hand literature.3 However, many clinicians have found both this amount of time and, sometimes a single orthosis, inadequate to accomplish tendon or bone healing and extensor tendon balance throughout the finger. For this reason, clinicians have sought alternate regimens to restore not only active DIP extension and to minimize lag, but also to minimize PIP hyperextension and the creation of a swan neck finger imbalance.
Literature about zone I extensor injury has expanded to include as many as 16 weeks of orthosis management.4,5 This lengthy treatment time usually does not involve constant DIP extension for this entire duration. Rather it consists of an initial period of continuous immobilization coupled with AROM of gradually increasing duration and motion arcs. At one time, clinicians thought that if an extensor lag persists after the 6-week period of immobilization, then orthosis management was less likely to resolve the problem. With extended and comprehensive management programs, we see better outcomes.
Delayed patient presentation does not constitute a contraindication to orthosis management for mallet finger injuries.6,7 The therapist will want to know whether the mallet involves a tendon substance tear or a bony avulsion. Therapists who receive referrals to manage a mallet finger when the patient reports the absence of x-ray assessment will be well-advised to refer the patient back to the referral source with a suggestion for radiography. Given that a certain level of bone involvement may indicate the need for surgery, one will want to be certain that the patient has received thorough physician evaluation.
Initially, mallet finger management includes:
- Patient education about injury and injury management, stressing the importance of Initial continuous immobilization
- Edema management as indicated
- Orthosis management of the DIP and sometimes of both the PIP and DIP joints
- ROM to the proximal joints of the involved finger.
- Assessment of pain including whether the physician has prescribed/recommended any analgesic including OTC medications, will facilitate patient comfort.
The key component to zone I extensor tendon management consists of full-time orthosis immobilization of the DIP for 6-10 weeks in slight hyperextension or in full extension in the case of unavailable hyperextension. While OTC DIP extension orthoses exist, they often fail to fit well or to ideally position the DIP. Custom orthosis fabrication is the highest level of care and offers the greatest possibility for compliance. It offers individualized fit and DIP position, the greatest stability on the digit and, the lowest profile option. The characteristic of minimal bulk makes living with the orthosis over the many weeks required much more tolerable. The fabricating clinician must take extreme care not to hyperextend the joint to the point when the skin becomes exsanguinated (blanches). Skin maintained in this condition for too long will undergo necrosis.8 See image below with finger-based orthoses. Much of the following extensor tendon management guidelines come from the work of Bobbi Owsley OTR CHT in connection with her work at Hand Surgery Associates in Denver, CO. This treatment guideline has not been published but reflects extensive research prior to its development and consistent upgrades to improve outcomes.
At the time of initial evaluation and orthosis management initiation, the therapist fabricates a custom orthosis to position the DIP in slight hyperextension or maximum extension if the DIP joint cannot hyperextend. (Images 1, 2) Reinforcement of this strategic position with tape (consider a strong kinesiotape such as RockTape® (2001 TW Alexander Drive Durham, NC 27709 USA General inquiries: (408) 213-9550) stretched to almost maximum length) helps prevent loss of tendon/bone continuity. While many orthoses designs exist, a consensus exists for the use of waterproof casting material. The therapist will also assess whether the patient has a tendency to hyperextend at the PIP. If the patient already has PIP volar plate laxity, the patient should receive, as soon as possible, a PIP extension block orthosis that also allows full PIP flexion. (Images 3, 4A, 4B) To encourage adjacent joint ROM, the patient receives instruction to perform maximum comfortable PIP and MCP joint AROM during week 1. The therapist instructs the patient to avoid PIP hyperextension.
The patient should return to the therapist 1x per week for orthosis and skin checks until week 6 to 8. At week 6-8, the therapist instructs the patient to block the PIP joint in mid flexion and then actively and gently flex the DIP followed by active extension. If the clinician observes a lag, the patient returns to continuous orthosis wear for at least another week. If the lag is greater than a few degrees, the therapist may choose to delay reexamination of DIP extension for another 2-3 weeks. For a truly significant lag, the therapist may encourage the patient to return to the treating physician.
When the patient can remove the orthosis and, with the PIP blocked in mid flexion, actively maintain extension with slight or no lag, active mobilization of the DIP can begin. Custom fabricated finger flexion templates guide the patient in the appropriate amount of active flexion—followed by extension—for the point in time after immobilization. The progression of these templates provides an effective program for gradually increasing flexion since clinicians will want to limit full composite flexion to prevent early overstretching. (Images 5A, 5B, 5C)
The patient continues to wear the DIP extension orthosis—and if needed the PIP extension block orthosis—at all times except when performing AROM exercise. Recommendations for frequency and repetition vary, but one clinic guideline that has provided successful outcomes called for 50 repetitions of DIP extension 4 times per day. At week 11, the exercise template may allow 40-45° of DIP flexion and the patient may perform gentle composite finger flexion. At 12-13 weeks from initiation of orthosis management, patients who have performed AROM exercise and demonstrate full or near full DIP extension, can begin to wean slowly from their DIP extension orthosis. They can stop using their exercise templates and can begin more forceful, pain free, composite finger flexion. Patients may benefit from night extension orthosis wear for several months to counterbalance flexion postures during the day.
Zone I and II extensor tendon post-surgical management
While the preponderance of literature addresses closed, acute zone I and II extensor injuries (mallet injury), lacerations and reconstruction of chronic DIP extensor lag does necessitate surgical intervention. Many therapy guidelines do not differentiate between closed/acute and surgical post-operative management interventions. They advocate treatment of all zone I and II injuries in the same manner and with the same timeline for immobilization/mobilization of the DIP.
Some of the needed differences for post/surgery management include the following:
- Surgery specific patient education
- Wound care/ dressing assessment
- Edema management
- Protective orthosis fabrication/application
- Scar management when appropriate
Personal interviews with several hand surgeons (L Hurst MD, W Kleinman MD and D LaLonde MD) revealed a general consensus regarding post-surgical management. All shared concerns about the size and fragility of the tendon adjacent to the DIP joint. They all preferred at least 6 weeks of immobilization of the DIP in extension with pain free PIP AROM as soon after surgery possible. At 6 weeks post-surgery, they advocate for active and active-assisted DIP flexion, with interval orthosis protection of the DIP joint. Kleinman added the known caveats that sutures can pull out if loaded too early and the tendon at this level is highly predisposed to pseudo-tendon formation and concomitant extensor lag if moved too early. DIPs that demonstrate stability and reasonable AROM can initiate PROM at 8-10 weeks after surgery. One chapter on extensor tendon management9 added the statement “There is no compelling rationale for an early motion protocol after repair of zone I or II extensor tendon injuries at this time.”
However, articles10,11 describing various approaches to chronic mallet surgical reconstruction describe good to excellent outcomes that include initiation of active DIP motion exercises at 4 weeks after surgery. These same articles describe intermittent and night orthosis wear for an additional 12 to 16 weeks.
While no one has yet published on research about a specific early motion program, the fact that many DIPs become extremely stiff after extensor tendon repair should compel us to further investigate the possibility of mobilizing the DIP more quickly after surgery. Certainly this depends on input from the surgeon regarding tendon status and quality of repair. Extremely fragile repairs and the specifics of an individual patient will always influence the mobilization schedule. Given the successes of Suzuki and Rozmaryn, we might want to consider a gentle motion regimen, with template orthoses guidance, beginning at 4 weeks rather than 6.
