Three Cast Techniques for the Treatment of Extra-Articular Metacarpal Fractures: Comparison of Short-Term Outcomes and Final Fracture Alignments

Tavassoli, Lieutenant Commander Jeff DO; Ruland, Commander Robert T. MD; Hogan, Lieutenant Commander Christopher J. MD; Cannon, Commander David L. MD

Journal of Bone & Joint Surgery - American Volume:
doi: 10.2106/JBJS.D.03038
Scientific Articles
Abstract

Background: Most extra-articular metacarpal fractures can be managed nonoperatively. While the conventional wisdom is that the metacarpophalangeal joint should be immobilized in a position of flexion, alternative methods for cast immobilization have been described. The purpose of this study was to retrospectively evaluate three methods of closed treatment; specifically, we investigated whether the position of immobilization of the metacarpophalangeal joint or the absence of a range of motion of the interphalangeal joints affected the short-term outcome or fracture alignment.

Methods: Between November 2000 and April 2004, extra-articular metacarpal fractures were immobilized for five weeks in one of three ways: with the metacarpophalangeal joints in flexion and full interphalangeal joint motion permitted (Group 1); with the metacarpophalangeal joints in extension and full interphalangeal joint motion permitted (Group 2); and with the metacarpophalangeal joints in flexion, the interphalangeal joints in extension, and no interphalangeal joint motion permitted (Group 3). Radiographs and the range of motion were evaluated at five weeks after application of the cast, and the range of motion and grip strength were assessed at nine weeks.

Results: Two hundred and sixty-three patients met the inclusion criteria. At five weeks, there was no difference among the treatment methods with regard to the range of motion or the maintenance of fracture reduction. At nine weeks, there was no significant difference with regard to the range of motion or grip strength.

Conclusions: When immobilization was discontinued by five weeks, the position of the metacarpophalangeal joints and the absence or presence of interphalangeal joint motion during the immobilization had little effect on motion, grip strength, or fracture alignment. This finding contradicts the conventional teaching that the metacarpophalangeal joint must be immobilized in flexion to prevent long-term loss of joint extension. Patient comfort, ease of application, and the surgeon's familiarity with the technique should influence the choice of immobilization.

Level of Evidence: Therapeutic Level III. See Instructions to Authors for a complete description of levels of evidence.

Author Information

1 Bone and Joint/Sports Medicine Institute, Charette Health Sciences Center, 620 John Paul Jones Circle, Portsmouth, VA 23708. E-mail address for C.J. Hogan: cjhogan@mar.med.navy.mil

Article Outline

The goal of treatment of extra-articular metacarpal fractures is rapid restoration of function with maintenance of acceptable alignment (Table I)1. Because an anatomic reduction is unnecessary for an excellent functional result, most extra-articular metacarpal fractures can be treated with closed reduction and immobilization in a cast1-7. Time-honored conventional wisdom that is often repeated in the trauma and hand surgery literature and in countless orthopaedic textbooks is that metacarpal fractures should be immobilized with intrinsic-plus or “safe” positioning of the hand to neutralize the potentially deforming forces of the intrinsic muscles on the reduced fracture and to prevent loss of metacarpophalangeal joint flexion due to contracture of the collateral ligaments1,4-7. Excellent clinical results have been obtained with cast immobilization in the intrinsic-plus position7 and with immobilization that restricts metacarpophalangeal joint extension but allows motion of the proximal and distal interphalangeal joints6,8. In contrast, others have challenged the conventional teaching by applying casts that restrict metacarpophalangeal joint flexion while permitting full interphalangeal joint motion9. These authors have also reported excellent results following treatment.

The purpose of this study was to evaluate three methods of closed treatment. We specifically investigated whether the position of immobilization of the metacarpophalangeal joint or the absence of interphalangeal joint motion affected short-term functional outcome or final fracture alignment. We hypothesized that there would be no significant differences among these treatment groups with regard to the ultimate fracture alignment or range of motion following cast removal.

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Materials and Methods

We retrospectively reviewed the charts of all patients who had presented to our orthopaedic department between November 2000 and April 2004 with an isolated, closed extra-articular fracture of the metacarpal, regardless of the location within the bone (neck, shaft, or epibasilar). Patients were excluded if they were less than eighteen years old or greater than sixty years old or if the fracture demonstrated a rotational or angular deformity that could not be reduced and maintained within the guidelines presented in Table I1,10.

Each patient was treated by one of three surgeons. Each surgeon had a preferred method of cast immobilization, which he applied to every one of his patients regardless of the metacarpal involved or the location of the fracture within the metacarpal. The first method (Group 1) flexed the metacarpophalangeal joints while permitting a full range of motion of the interphalangeal joints (Figs. 1-A and 1-B). The second method (Group 2) placed the metacarpophalangeal joints in extension and permitted a full range of motion of the interphalangeal joints (Figs. 2-A and 2-B). The third method (Group 3) utilized the intrinsic-plus position, flexing the metacarpophalangeal joints while immobilizing the interphalangeal joints in extension (Figs. 3-A and 3-B).

Each patient received a 5-mL injection of 1% lidocaine through a 25-gauge needle into the fracture hematoma, and fingertrap traction was used to facilitate fracture reduction. In Groups 1 and 3, traction was discontinued during cast application to allow metacarpophalangeal joint flexion. In Group 2, immobilization of the metacarpophalangeal joints in extension permitted three-point molding of the cast under traction. Occupational therapy was not used during the immobilization period, and the cast was always removed by five weeks.

Charts and radiographs were reviewed to identify the metacarpal that was involved; the location and type of the fracture; the fracture alignment as seen on anteroposterior, lateral, and oblique radiographs after the application of the cast and again after the cast was removed; the range of motion five weeks after application of the cast (immediately after cast removal) and at nine weeks; and grip strength at nine weeks.

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Statistical Analysis
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A control analysis was performed to determine whether the metacarpal that was involved or the fracture location within the metacarpal influenced the surgeon's choice of immobilization. A one-way analysis of variance was performed to compare the three groups with regard to the change between the angulation after the initial application of the cast and the angulation seen after immobilization was discontinued. The same statistical analysis was performed to compare the groups with regard to the grip strength of the injured hand as a percentage of that of the unaffected hand at nine weeks. A chi-square test for proportions was used to compare the ranges of motion among the three groups at five weeks and at nine weeks.

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Results

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The initial chart review identified 282 patients, 263 of whom met the inclusion criteria. The average age was 25.9 years (range, eighteen to fifty-four years). The distributions of the metacarpals involved and the locations of the fractures within the metacarpals are listed in Figure 4. There were eighty-nine patients in Group 1, ninety-seven in Group 2, and seventy-seven in Group 3. The control analysis demonstrated that selection bias had not occurred—i.e., the involved metacarpal and the location of the fracture within the metacarpal had no effect on which cast was selected (p = 0.172).

The change in the fracture angulation from the time that the cast was applied to the time that it was removed was known for 187 patients: sixty-six in Group 1, sixty-four in Group 2, and fifty-seven in Group 3. Regardless of the method of immobilization, fracture alignment was always maintained according to the guidelines listed in Table I1,10. The average increase in angulation (and standard deviation) was 3° ± 6° in Group 1, 2° ± 6° in Group 2, and 1° ± 3° in Group 3. There was no significant difference among the treatment groups (p = 0.255).

Grip strength at nine weeks after application of the cast was documented for 155 patients: fifty-four in Group 1, fifty-four in Group 2, and forty-seven in Group 3. Because hand dominance was not consistently recorded, grip strength was calculated as the percentage of the grip strength of the uninjured hand. Grip strength averaged 87% of that of the uninjured hand in Group 1; 85%, in Group 2; and 90%, in Group 3. With the numbers available, there was no significant difference in grip strength among the three methods of immobilization (p = 0.844).

The range of motion at five weeks after application of the cast (immediately after cast removal) was known for all 263 patients. At that time, a full range of motion of the metacarpophalangeal and interphalangeal joints was seen in 89% of the patients in Group 1, 80% of those in Group 2, and 82% of those in Group 3. The difference among the groups was not significant (p = 0.233). At nine weeks, two patients in Group 1, one patient in Group 2, and one patient in Group 3 had not regained a full range of motion. The average total active arc of motion for these patients was 250°.

Functional recovery from the injury was determined by the ability of the patient to resume his or her normal activities without pain or limitation. All active-duty military personnel returned to full, unrestricted duty status at the end of the nine-week treatment course. All dependents of the military personnel resumed their prior levels of vocational and avocational activities.

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Discussion

The metacarpal head is not spherical, and this creates a cam effect that increases the tension in the collateral ligaments with progressive flexion of the metacarpophalangeal joint. Theoretically, prolonged immobilization of the metacarpophalangeal joint in extension can lead to contracture of the collateral ligaments, ultimately limiting metacarpophalangeal joint flexion. Concerns about the debilitating effects of latent stiffness of the metacarpophalangeal joint have led most authors to recommend placing that joint in flexion during the closed management of metacarpal fractures1,4-7.

King et al.9 challenged this premise by treating metacarpal neck fractures with a cast that restricted metacarpophalangeal joint flexion but permitted a full range of motion of the interphalangeal joints.

In our clinical series, patients were separated into three groups on the basis of the method of immobilization. Theoretically, all of the immobilization protocols could lead to prolonged finger stiffness: metacarpophalangeal joint flexion contractures and intrinsic tightness in Group 1, metacarpophalangeal joint extension contractures in Group 2, and metacarpophalangeal joint flexion contractures with extensor mechanism adhesions and intrinsic tightness in Group 3.

Despite these concerns, there was no significant association between the method of immobilization and the recovery of motion immediately after removal of the cast. Additionally, there was no difference among the three methods with regard to the grip strength, compared with that of the unaffected hand, one month following cast removal. Also, all three; methods of immobilization maintained acceptable fracture alignment1,10.

One potential criticism of this study is that all extra-articular fractures, regardless of their location in the metacarpal, were considered together in the initial patient population. Classically, extra-articular fractures of the metacarpal have been divided into neck, shaft, and epibasilar injuries because the location of the fracture dictates how much residual deformity can be tolerated1,10.

The position of the metacarpophalangeal joint and the absence or presence of interphalangeal joint motion during the immobilization had little effect on the short-term functional outcome or final fracture alignment following immobilization that had been discontinued by five weeks. At least 80% of the patients in each of the treatment groups demonstrated full motion of the metacarpophalangeal and proximal interphalangeal joints immediately following cast removal. Only four patients did not recover full motion within nine weeks after the injury. These excellent results regarding motion may reflect the characteristics of our patient population, which consisted of young active-duty military personnel and their dependents. One cannot assume that an elderly population, who are prone to the development of stiffness, would demonstrate the same trend.

On the basis of this retrospective review, two of the three surgeons altered their preferred method of immobilization of extra-articular metacarpal fractures, and our recommendation is to treat these injuries with a cast that places the metacarpophalangeal joints in extension and allows full motion of the proximal interphalangeal joints. With the injured digit in fingertrap traction, application of this cast is simple and it allows three-point molding of the cast for this bending-type fracture. Ultimately, patient comfort, ease of application, and the surgeon's familiarity with the technique should influence the choice of immobilization. ▪

The authors did not receive grants or outside funding in support of their research or preparation of this manuscript. They did not receive payments or other benefits or a commitment or agreement to provide such benefits from a commercial entity. No commercial entity paid or directed, or agreed to pay or direct, any benefits to any research fund, foundation, educational institution, or other charitable or nonprofit organization with which the authors are affiliated or associated.

The views expressed in this article are those of the authors and do not reflect the official policy or position of the Department of the Navy, the Department of Defense, or the United States government.

Investigation performed at the Bone and Joint/Sports Medicine Institute, Charette Health Sciences Center, Portsmouth, Virginia

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