Commentary & Perspective

Commentary & Perspective on
"Use of a Cast Compared with a Functional Ankle Brace After Operative Treatment of an Ankle Fracture. A Prospective, Randomized Study"
by Hannu Lehtonen, MD, et al.

Commentary & Perspective by
Paul Tornetta III, MD*,
Department of Orthopaedic Surgery, Boston Medical Center, Boston, MA

Lehtonen et al. compared the subjective and functional outcomes of postoperative treatment of ankle fractures with either a cast or functional bracing during the first six weeks after internal fixation. The study design, prospective and randomized, is good but only a small number of patients were included. The postoperative protocols differed only in the degree of mobilization during the first six weeks after operative fixation of unstable and/or displaced Weber type-A or B ankle fractures.

In one group, patients were allocated to immobilization in a below-the-knee cast, restricted to non-weight-bearing for two weeks, and then allowed partial weight-bearing for four weeks until the cast was removed, at which time full weight-bearing was allowed.

The second group was allocated to treatment with a functional ankle brace for the first six postoperative weeks and were "encouraged" to perform daily active and passive range-of-motion exercises of the ankle and subtalar joints without the brace immediately postoperatively and until normal gait was achieved. The weight-bearing regimen was identical to that used in the cast group, but the patients in the brace group were encouraged to perform the range-of-motion exercises. The authors did not specifically describe these exercises or whether their performance was supervised. From the results, it seems unlikely that the exercises were supervised.

The authors found no differences in range of motion or outcome between the two treatment groups at any of the follow-up examinations (six weeks, twelve weeks, fifty-two weeks, and two years). These findings are in contrast to those of other reports^1-4, in which patients who were treated without cast immobilization had better early range of motion. How does one explain the lack of objective improvement in the range of motion of patients in both treatment groups at six weeks, when one group had cast immobilization for six weeks and the other performed range-of-motion exercises? One possible explanation is that the patients who were in the brace group did not, in fact, do their exercises or did not do them effectively so that their range of motion at six weeks did not differ from that of the cast group.

The patients included in this study had a wide variety of ankle injuries (Table 1). The authors indicated that there were twenty-nine unimalleolar fractures and only one deltoid ligament injury in the cast group, so that twenty-eight patients possibly had a stable ankle fracture. In the brace group, there were thirty unimalleolar fractures of which five had a deltoid injury, so that only twenty-five had potentially stable injuries. On the basis of the data provided, it is quite possible that the majority of these patients, despite having a minimum of 2 mm of displacement at the fibular fracture, may have had stable ankles (an intact deltoid) that would allow full weight-bearing and an immediate range of motion without surgery. If this were the case, then many of these patients may have suffered surgical complications, e.g., wound complications, etc., without a potential surgical benefit.

Despite the weaknesses of this study, the authors found a significant difference in complication rates between the two groups (p = 0.0005). The brace group, which had early range of motion without cast immobilization during the first several postoperative weeks, had a high rate (66%) of wound complications. Specifically, there were sixteen superficial and four deep wound infections, in addition to three wound dehiscences and one loss of internal fixation. In contrast, the cast group had four superficial infections. In the literature, some authors³ have reported no wound complications and others¹ have reported an increase in them with early aggressive management and less immobilization after ankle fixation.

In summary, although this study suffers from the small n, an implied lack of supervision of the range-of-motion exercises, and the lack of a power analysis, I would agree with the authors' finding that early immobilization after surgical treatment of an ankle fracture may be beneficial until the wound heals. At that time, it appears that it would be safe to include a regimen of partial weight-bearing if the surgeon believes that this would further rehabilitation. Finally, if range-of-motion exercises are considered, one may infer from the lack of improvement seen in the brace group in this study, which contrasts with the improvement seen in patients treated comparably in other studies^2,4, that a more supervised and careful course of physical therapy may be required to reap the potential benefits of this postoperative treatment.

*The author did not receive grants or outside funding in support of the research or preparation of this manuscript. He 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 author is affiliated or associated.

References

1. Sondenaa K, Hoigaard U, Smith D, Alho A. Immobilization of operated ankle fractures. Acta Orthop Scand. 1986;57:59-61.
2. Cimino W, Ichtertz D, Slabaugh P. Early mobilization of ankle fractures after open reduction and internal fixation. Clin Orthop. 1991;267:152-6.
3. Egol KA, Dolan R, Koval KJ. Functional outcome of surgery for fractures of the ankle. A prospective, randomised comparison of management in a cast or a functional brace. J Bone Joint Surg Br. 2000;82:246-9.
4. Ahl T, Dalen N, Selvik G. Mobilization after operation of ankle fractures. Good results of early motion and weight bearing. Acta Orthop Scand. 1988;59:302-6.