13 Extensor Lag
13.1 Patient History Leading to the Specific Problem
A 23-year-old man presents with extensor lag of his index finger approximately 10 weeks after primary repair of the extensor indicis proprius and extensor digitorum communis to the index finger. The patient initially sustained an injury to the dorsum of the hand while using a grinding apparatus (▶Fig. 13.1). The wound demonstrated some mild contamination and tendon ends that were somewhat ragged with a relatively long zone of injury. A repair was effected using a combination of Krakow and horizontal mattress sutures. Following repair of the extensor tendon and closure of the skin, a forearm-based splint was placed with the index through small fingers in extension. At 10 weeks, and despite regular hand therapy, the patient was noted to have an extensor lag of approximately 30 degrees at the metacarpophalangeal (MCP) joint in addition to extrinsic stiffness of the index finger, preventing flexion of the proximal interphalangeal (PIP) joint beyond approximately 10 degrees with the MCP fully flexed (▶Fig. 13.2).
Fig. 13.1 Upon initial presentation, the patient demonstrated a laceration overlying the second metacarpal with a long zone of injury including approximately 3 cm of the extensor indicis proprius and extensor digitorum communis to the index finger.
Fig. 13.2 (a) At follow-up at 10 weeks, the patient demonstrates an extensor lag at the metacarpophalangeal (MCP) joint of approximately 30 degrees upon attempted extension. (b) In addition to the extensor lag, there is extrinsic tightness of the proximal interphalangeal (PIP) joint with inability to flex the PIP joint beyond approximately 10 degrees with the MCP fully flexed.
13.2 Anatomic Description of the Patient’s Current Status
The patient’s dorsal soft tissues are healed without excessive edema, inflammation, or immature scar (▶Fig. 13.3). The scar demonstrates some hypertrophy as well as firmness at the middle of its length consistent with adhesions. Individually, the joints of the index finger and the wrist may be taken through a nearly full passive range of motion. Actively, the patient is able to extend the proximal and distal interphalangeal joints fully but is unable to extend the digits beyond 30 degrees at the MCP joint with the wrist positioned in neutral. Extension at the MCP joint improves to 5 degrees short of full with the wrist in approximately 40 degrees of flexion. There is palpable contraction of the extensor muscles within the forearm, and at the level of the scar, the skin demonstrates tethering between the extensor tendon and the skin with attempt at passive flexion of the finger.
Fig. 13.3 At 10 weeks, the prior incision is well healed. There is some evidence of hypertrophy of the scar. The surrounding tissues are without significant edema or signs of inflammation.
13.3 Recommended Solution to the Problem
One should first realize that supervised hand therapy can minimize extensor lag after extensor tendon repair. Appropriate therapy provides limited motion to minimize adhesion formation while preventing gapping at the repair site. If adhesions do form and formal hand therapy is unable to improve active motion for a period of approximately 12 weeks, tenolysis may be considered. Examination of the patient is critical to determining the presence of tendinous adhesions within the digits, hand, wrist, or forearm. Adhesions ultimately limit tendon excursion, and total active range of motion of the involved portion of the extremity is decreased. Passive range of motion may be nearly normal.
Other causes of extensor lag should also be ruled out. Flexor tendon adhesions, associated fracture shortening, bow stringing of extensor tendons over the wrist, or sagittal band rupture may also cause extensor lag. Once other causes of extensor lag have been ruled out and adhesions have been localized, tenolysis may be performed. Use of local anesthesia and wide-awake surgery allows the surgeon to verify intraoperatively that all adhesions have been addressed and that active motion has been restored. Following tenolysis, meticulous hemostasis may limit postoperative swelling and inflammation, which facilitates early motion of the digits and helps prevent further adhesions. The patient should begin formal hand therapy no more than 1 week following surgery to prevent recurrence of adhesions.
13.3.1 Recommended Solution to the Problem
• Adhesions between the tendons and surrounding soft tissues require tenolysis to improve active motion if therapy fails.
• Physical examination will help localize the likely area of adhesions.
• Ideally, surgery should be performed using wide-awake, local anesthesia to allow the patient to demonstrate active motion of the involved tendons to confirm improvement intraoperatively.
• Obtaining meticulous hemostasis following repair can help minimize edema and inflammation, which may help prevent further adhesions.
• Though it is difficult to prevent extensor lag entirely, appropriate hand therapy reduces adhesions and prevents gapping of tendon repairs, minimizing the chance of extensor lag after tendon repair.
13.4 Technique
The patient is taken to the operating theater and placed into a supine position using a hand table. Surgery can be performed under local anesthetic to allow the patient to participate in an examination during and after the tenolysis. Anesthetic with epinephrine can be used to minimize bleeding in lieu of using a tourniquet. If a tourniquet is used, the procedure should be performed expediently to permit an evaluation prior to development of tourniquet-associated paralysis. An incision is made over the dorsum of the digits, hand, wrist, or forearm, in line with the tendons to be dissected. If multiple tendons are involved, the skin and subcutaneous tissues can be elevated radially and ulnarly over the dorsum of the wrist. The tendons should be identified proximal and distal to the area of adhesions to ensure that the tendons are dissected in their entirety from the surrounding tissue and intratendinous dissection is prevented. The extensor retinaculum over the wrist and the sagittal bands must be preserved to prevent bow stringing of the tendons or lag associated with sagittal band rupture.
In our case, once the tenolysis was complete, an area of attenuated tendon was noted where the repair appeared to have gapped. This was imbricated using a combination of figure-of-eight and horizontal mattress sutures (▶Fig. 13.4).
Once the tendons are freed from the surrounding tissue, the patient is asked to actively range the digits and wrist in order to confirm that the tenolysis is complete (▶Fig. 13.5). After active motion of the affected digits has been restored, attention is turned to obtaining excellent hemostasis within the wound bed. Closure is then performed and a sterile dressing is applied along with a splint with the digits in a resting position. The splint and dressings should be removed within a week to permit hand therapy with a focus on active motion and prevention of further adhesions.
13.4.1 Steps for the Procedure
1. An incision is made over the suspected site of adhesions.
2. The tendon is dissected from surrounding tissues beginning proximal and distal to the affected area to prevent intratendinous dissection, which can lead to tendon rupture.
