Abstract
Background Ulnar-sided wrist pain is a common problem encountered by hand surgeons. Symptomatic recurrent subluxation of the extensor carpi ulnaris (ECU) tendon has become increasingly recognized as one of the pathological conditions leading to ulnar-sided wrist pain. Surgical reconstruction of the subsheath is usually needed. ECU tendon subsheath reconstruction with the periosteal flap was first described by Schlesinger in 1907. Since then, various other techniques have been widely used. We describe a technique of ECU subsheath reconstruction using the dorsal capsule of the distal radioulnar joint (DRUJ).
Description of Technique Two hand surgeons performed the surgeries with the same steps taken each time. A detailed description of our surgical technique, with the dorsal capsule of the DRUJ used to reconstruct the ECU tendon subsheath, is illustrated.
Patient and Methods Patients who presented with symptomatic ECU instability despite conservative treatment or who have failed primary subsheath repair were offered this surgical option. Patients were followed up postoperatively for an average duration of 6.7 months in our outpatient clinics for assessment of wrist function. The surgical outcomes were reviewed and graded with the Modified Mayo Wrist Score (MMWS).
Results All but one of the seven patients had an overall improvement in their range of movement of the wrist, grip strength, and pain scores. Four patients had excellent outcomes on the MMWS, one of whom had an asymptomatic recurrence seen on dynamic ultrasound. Two patients required subsequent surgeries: one had an excellent outcome and the other had a poor outcome on the MMWS.
Conclusion We present our first seven cases of ECU subsheath reconstruction with the dorsal capsule of the DRUJ. Our results in the short term have been satisfactory. The technique does not disrupt the integrity of the extensor retinaculum, which is essential for optimal extensor tendon function, and can also be considered as an option to salvage failed procedures.
Keywords: extensor carpi ulnaris tendon, subluxation, wrist pain, fibro-osseous subsheath, reconstruction
Symptomatic recurrent subluxation of the extensor carpi ulnaris (ECU) tendon has become increasingly recognized as one of the pathological conditions leading to ulnar-sided wrist pain. Patients usually complain of clicking during forearm supination, with the tendon subluxation palpable and visible.
Surgery to stabilize the ECU tendon is indicated when conservative management fails to alleviate the pain. 1 Schlesinger 2 was the first to describe the treatment of isolated recurrent traumatic ECU tendon dislocation with the use of a periosteal flap from the ulna to create a new compartment for the ECU tendon under the extensor retinaculum. Spinner and Kaplan 3 published the first English report describing ECU stabilization by reconstructing the subsheath from a dorsal strip of the extensor retinaculum.
Since then, various authors have described their techniques for the surgical treatment of ECU tendon subluxation. Some of the techniques include direct repair of the ECU subsheath, 1 4 ECU subsheath reconstruction with the retinacular sling, 4 fascial flap, 1 5 and tendon graft, 4 6 and ECU tendon stabilization with ulnar groove deepening and suture anchor, 7 just to name a few.
We describe a novel technique of ECU subsheath reconstruction using the dorsal capsule of the distal radioulnar joint (DRUJ). We report on the results of our series of seven cases to determine the efficacy of our reconstruction technique.
Surgical Technique
With the patient under general anesthesia, an L-shaped incision is made at the dorsal wrist, along the distal and medial borders of the ulnar head ( Fig. 1 ). Careful dissection proceeds, ensuring the dorsal cutaneous branch of the ulnar nerve is identified and protected. The extensor retinaculum is divided superficial to the extensor digiti quinti minimi (EDQM) tendon. EDQM tendon is retracted and the DRUJ capsule is identified ( Fig. 2 ). Under direct vision, the subluxation of the ECU tendon can be observed with ulnar deviation of the wrist. The ECU subsheath is then incised and the tendon is mobilized and retracted. An ulnar-based U-shaped flap is created from the dorsal capsule of the DRUJ exposing the ulnar head ( Fig. 3 ). The capsule flap is reinforced on the ulnar aspect with Vicryl 4–0 sutures. The dorsal capsule flap is passed beneath and then over the ECU tendon and back onto itself to envelop the ECU tendon, creating a new subsheath ( Fig. 4 ). This is secured with Vicryl 3–0 sutures. The ECU tendon is held securely in position with the new subsheath. The extensor retinaculum is then repaired with Vicryl 3–0 sutures. On table, examination is carried out demonstrating that following repair there is no subluxation of the ECU tendon on wrist pronation and supination. The wound is then closed in layers. Following skin closure, a sugar tong back slab is applied with the elbow flexed and the wrist in neutral. After the immediate postoperative period, patients will be placed on a Muenster splint for 6 weeks to immobilize the wrist before commencing range of motion (ROM) exercises with the hand therapists.
Fig. 1.
L-shaped incision via a dorsal approach.
Fig. 2.
Exposure of the extensor carpi ulnaris subsheath.
Fig. 3.
Raising of the ulnar-based distal radioulnar joint dorsal capsule flap, exposing the ulnar head beneath.
Fig. 4.
( A, B ) Creation of the extensor carpi ulnaris neo-subsheath with the dorsal capsule flap reflected onto itself to envelope the extensor carpi ulnaris tendon.
Patient and Methods
Between 2017 and 2019, patients with symptomatic ECU instability, despite conservative management of 6 weeks of immobilization combined with hand therapy thereafter or with failed primary subsheath repair, were offered the option of ECU subsheath reconstruction. The primary surgeon for the case assessed the patient preoperatively and clinically diagnosed ECU subluxation. Radiological confirmation was done with dynamic ultrasound or wrist magnetic resonance imaging (MRI). Informed consent was taken. Two hand surgeons, who are highly experienced specialists, performed the surgeries with the same steps taken each time. Clear operative steps and intraoperative findings were documented on the hospital health records system.
Patients were followed up postoperatively for at least 3 months in outpatient clinics. The patients were reviewed by a team of doctors with varying levels of hand surgery experience. Surgical outcomes comprising of symptoms, functional status, and clinical examination findings were recorded in the hospital health records system with each visit. We used the Modified Mayo Wrist Score (MMWS), a modification of the Green and O'Brien score, to evaluate our outcomes. It has four parts: pain, functional status, ROM, and grip strength ( Table 1 ). Each part is scored out of 25 points. The tallied scores from 0 to 100 indicate wrist function. Scores of 90 to 100 indicate excellent function, 80 to 89 good, 65 to 79 satisfactory, and <65 poor.
Table 1. Modified Mayo Wrist Score (MMWS).
| Category | Points | Description | |
|---|---|---|---|
| Pain score | 25 | No pain | |
| 20 | Mild occasional pain | ||
| 15 | Moderate, tolerable pain | ||
| 0 | Severe, intolerable pain | ||
| Functional status | 25 | Returned to regular employment | |
| 20 | Restricted employment | ||
| 15 | Able to work, unemployed | ||
| 0 | Unable to work due to pain | ||
| Range of motion | Degrees of hand arc | % of normal | |
| 25 | 120 degrees or more | 100% | |
| 15 | 90–119 degrees | 75–99% | |
| 10 | 60–89 degrees | 50–74% | |
| 5 | 30–59 degrees | 25–49% | |
| 0 | <30 degrees | <25% | |
| Grip strength (% of normal) | 25 | 100% | |
| 15 | 75–99% | ||
| 10 | 50–74% | ||
| 5 | 25–49% | ||
| 0 | <25% | ||
| Final score | 90–100 | Excellent | |
| 80–89 | Good | ||
| 65–79 | Satisfactory | ||
| <65 | Poor | ||
The patient-reported pain score is rated as none (25 points), mild (20 points), moderate (10 points), or severe (0 points). Functional status is graded by the ability to return to work; those who returned to regular employment were assigned 25 points, those with restricted activities 20 points, those unemployed 15 points, and those unable to work 0 points. ROM is measured as the degrees of active flexion and extension arc: 120 degrees or more, 25 points; 90 to 119 degrees, 15 points; 60 to 89 degrees, 10 points; 30 to 59 degrees, 5 points; and less than 30 degrees, 0 points. The grip strength of the affected hand is compared with that of the unaffected hand: 100% grip strength, 25 points; 75 to 99%, 15 points; 50 to 74%, 10 points; 25 to 49%, 5 points; and less than 25%, 0 points.
Results
Of the seven patients, three were males and four were females. The median age is 30 years old (range: 19–48 years old). All patients were right-hand dominant with three cases involving the left wrist and four the right wrist. None of the patients were professional athletes and they had varying levels of physical fitness and activity. All seven patients presented with ulnar-sided wrist pain. Case 3 who presented with ulnar-sided wrist pain had a previous ECU reconstruction with the extensor retinaculum 2 years ago. Case 5 had previous left wrist arthroscopic debridement and triangular fibrocartilage complex repair 5 years ago.
The mean follow-up duration postoperatively was 6.7 months (range: 3–15 months). All but one of the patients had an overall improvement in their range of movement of the wrist, grip strength, and pain scores at their latest outpatient follow-up. Five patients reported no pain, while two patients reported mild pain. Four patients returned to work and resumed normal activities, two were still on hospitalization leave with restricted function, and one remained unemployed. Patient outcomes range from poor to excellent on the MMWS. Four had excellent scores, two satisfactory, and one poor ( Table 2 ). Case 5, who scored excellent on the MMWS, had a recurrence of ECU subluxation as seen on dynamic ultrasound 3.5 months postoperatively.
Table 2. Patient demographics and results.
| Case | Age/sex | Hand dominance | Hand involved | Duration of symptoms | Follow-up duration | Pain points | Functional status points | Range of motion points | Grip strength points | MMWS | Interpretation |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 19/M | Right | Left | 3 y | 3 mo | 25 | 25 | 25 | 15 | 90 | Excellent |
| 2 | 35/F | Right | Right | 3 mo | 15 mo | 25 | 25 | 25 | 15 | 90 | Excellent |
| 3 | 37/F | Right | Left | 6 wk | 11 mo | 20 | 20 | 15 | 5 | 60 | Satisfactory |
| 4 | 21/M | Right | Right | 2 mo | 5 mo | 25 | 25 | 25 | 15 | 90 | Excellent |
| 5 | 21/F | Right | Right | 6 y | 5 mo | 25 | 15 | 25 | 25 | 90 | Excellent |
| 6 | 48/M | Right | Left | 6 mo | 5 mo | 20 | 20 | 15 | 0 | 55 | Poor |
| 7 | 31/F | Right | Right | 2 mo | 3 mo | 25 | 25 | 15 | 10 | 75 | Satisfactory |
Abbreviations: F, female; M, male; MMWS, Modified Mayo Wrist Score.
Two patients required subsequent surgeries. Case 2 underwent wrist manipulation under general anesthesia 11 months after her ECU reconstruction surgery. She has since returned to work as a physiotherapist at a community hospital with no issues and scored excellent on the MMWS at her last follow-up. Case 6 developed ECU tendinitis requiring tenolysis surgery 5 months following ECU reconstruction surgery and subsequently required surgical debridement for surgical site wound infection 1 month thereafter. He scored poor on the MMWS at his last follow-up, with 0 points under grip strength.
Discussion
Ulnar-sided wrist pain due to soft-tissue injury is a relatively common problem encountered by hand surgeons in their clinics. Although symptomatic ECU subluxation used to be a rare cause for ulnar-sided wrist pain, it is becoming increasingly recognized. Painful signs and symptoms of ECU subluxation are reproduced by passive forearm supination combined with wrist ulnar deviation and flexion. 4 This same combination of motions generated by a pathologic force is also the mechanism of ECU injury.
Prompt and accurate diagnosis is of paramount importance for the correct treatment to be initiated. This can be done with proper clinical examination, supplemented by imaging modalities such as MRI and dynamic ultrasound. MRI can demonstrate ECU pathology with edema seen in the ECU tendon or sheath; however, it is limited as it is unable to pick up subluxation or abnormal anatomy of the ECU tendon. 8 Dynamic ultrasound is a better option for diagnosis. It is able to visualize the ECU tendon subluxating out of the ulnar groove on supination of the wrist and relocates into the groove on pronation. 8
The ECU tendon, as observed by Spinner and Kaplan, 3 is housed in a fibro-osseous tunnel deep to the extensor retinaculum. An intact fibrous subsheath is important in helping the ECU tendon maintain its position and, by doing so, keeps the DRUJ stable. Findings by Burkhart et al 4 and Palmer et al 7 also support this point. Burkhart et al also reported that a vertical septum on the ulnar side of the ECU tendon is important to prevent its subluxation. They noticed that a complete longitudinal tear of the structure was present in three of their patients who underwent surgery for symptomatic ECU subluxation.
While it is possible to conservatively manage ECU subluxation with 6 weeks of cast immobilization, 4 early surgical treatment is favored. 1 Inoue and Tamura 1 observed that if a tear of the subsheath occurs at the radial aspect, when the ECU tendon relocates into the ulnar groove it may lie superficial to the torn sheath, hence preventing the sheath from healing. Rowland 9 observed in his patient a considerable gap between the torn edges of the subsheath that would not have been anatomically impossible to heal without surgical intervention.
In our proposed technique, we reconstructed a new subsheath with a flap reconstructed from the dorsal capsule of the DRUJ. The flap was raised radially; in doing so, the integrity of the ulnar aspect of the new subsheath was not disrupted. The ulnar aspect was also reinforced with Vicryl sutures. This simulated a strong restraining structure at the ulnar wall to prevent the ECU tendon from moving in the ulnar direction as stated by Burkhart et al. 4
In the wake of other methods that use the extensor retinaculum, our technique preserves the integrity of the extensor retinaculum as it is important for extensor tendon function, the extensor retinaculum being a fibrous structure that holds the extensor tendons in place. Palmer et al 7 reported that an intact extensor retinaculum prevents bowstringing of the extensor tendons and maintains their anatomical linear loading. The bowstringing of extensor tendons can result in decreased power in finger extension, hence affecting hand function. The procedure also provides a viable option to salvage failed procedures.
However, there are several limitations to our study. It is a nonrandomized prospective review, with no control group, and an evaluation of a single group's experience of this novel technique. There is no standardized follow-up period in which postoperative assessment was done. The assessment of patients done pre- and postoperatively was performed by doctors with varying levels of hand surgery experience. There is also no blinding done to the surgeon, patient, and doctors in the clinic.
Our studies can be further improved with a randomized study with a larger cohort of patients. A longer term follow-up will be beneficial to assess the statistical significance of our surgical outcomes. We can also standardize the period of postoperative follow-up and have a regular batch of assessors evaluating hand function pre- and postoperatively. This technique does not disrupt the integrity of the extensor retinaculum, which is essential in extensor tendon function. This technique can also be considered an option to salvage failed procedures.
Funding Statement
Funding None declared.
Conflict of interest None declared.
Location of surgery performed: Department of Hand and Reconstructive Microsurgery, Singapore General Hospital.
References
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