Introduction

Elbow stiffness following trauma or posttraumatic heterotopic ossification (HO) results in functional limitation due to the complex anatomy of the elbow, which forms a congruent hinge. Elbow stiffness can be graded according to arc of flexion [1]. A very severe stiff elbow is defined as an elbow having a total arc of less than 30°, while a severely stiff elbow has a total arc of 31°–60° and a moderately stiff elbow, 61°–90°. As it results in very severe elbow stiffness with a range of motion (ROM) of 0°, an ankylosed elbow results in extremely limited movement.

Increased restriction at the joint and the necessity for difficult treatment modalities arise when the elbow is completely ankylosed. Most patients suffering from ankylosed elbows have complex pathoanatomy with elements of both extrinsic and intrinsic contractures [2]. Due to the complex pathology, arthroscopy often fails to result in complete release and thus open arthrolysis should be the optimal method. However, after complete open arthrolysis to correct the pathological changes, necessary ligaments may be simultaneously removed, resulting in associated complications such as postoperative instability. All these factors make this condition a daunting challenge for surgeons. Hence, finding an efficient and effective method to treat posttraumatic ankylosed elbows is of great importance.

The combination of arthrolysis and hinged external fixation has previously been reported to be safe and effective in the treatment of stiff elbows [3]. Consequently, in the current study, we retrospectively analyzed the clinical outcome of posttraumatic ankylosed elbows with a ROM of 0°, treated by open arthrolysis and monolateral hinged external fixation.

Patients and methods

From June 2006 to April 2010, 15 patients suffering from an ankylosed elbow were treated at our institution. They were treated by open arthrolysis and given immediate rehabilitation with a hinged external fixation (Orthofix Srl, Italy). Of the 15 patients 9 were men and 6 were women, with an average age of 37.9 years (range from 23 to 58 years) when arthrolysis was performed. The injury patterns in these 15 patients included distal humeral fracture in 10, elbow dislocation and radial head fracture in two each, and one olecranon fracture. All 15 patients had the elbow ankylosed at various degrees ranging from 30° to 85° and the active ROM before surgery was 0°. The Patient details are shown in Table 1.

Table 1 Details of 15 patients (15 elbows) with posttraumatic ankylosed elbow
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HO could be seen to block movement and even bridge across an articulation in 12 of the elbows. Laboratory findings such as blood calcium, serum phosphate and blood alkaline phosphatase levels were normal. The 12 patients underwent surgical arthrolysis more than 6 months after trauma or last surgery, and the appearance of cortical boundaries seen on serial direct radiographs indicated maturation of the HO. Figures 1,2,3, and 4 show the preoperative elbow ROM and imaging of the case 7 in our series.

Fig. 1
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The patient (case 7) tried to extend the elbow ankylosed at 40° preoperatively

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Fig. 2
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The patient (case 7) tried to flex the ankylosed elbow preoperatively

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Fig. 3
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Lateral and AP radiographs show HO over the anteromedial aspects of the elbow

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Fig. 4
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Three-dimensional CT shows the elbow with HO

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Surgical technique

A brachial plexus block with a tourniquet was used on all patients. Any old incision scars and the location of the pathology were taken into consideration to determine the approach and sequence to use. Eleven patients underwent arthrolysis by medial and lateral approaches, three patients by the posterior approach and one by posterior and lateral approaches. Subcutaneous anterior transposition of the ulnar nerve was performed after neurolysis in all patients including six patients, who had undergone anterior ulnar nerve transposition in previous operations.

The lateral incision was performed by the extended Kocher approach, mainly to release the anterior part of the elbow. Parts of the extensor muscle origins were reflected anteriorly to explore the anterior pathology. Since, in some cases the elbows were entirely encased in heterotopic bone which prohibited any movement, it was difficult to identify the articulation and resect heterotopic bone appropriately. Consequently, it was necessary to first remove the heterotopic bone with an osteotome and a rongeur in layers until the joint was encountered and then administer sharp blows to separate the heterotopic bone from the host bone. Afterwards, capsulectomy and arthrolysis of the coronoid fossae and humeroradial joint were also performed. The medial incision was then used for posterior release.

The medial incision began distally, curved along the ulnar nerve, and continued proximally to the upper arm. The ulnar nerve was identified and protected proximally at the medial border of the triceps. The bilateral margins of the triceps tendon were split to explore the posterior part of the elbow for arthrolysis. The triceps were reflected laterally and posteriorly from the medial side of the distal humerus to expose the olecranon fossa and the posterior aspect of the humerus for debridement. Heterotopic bone with the posterior capsule was excised in the same way as described above. The olecranon fossa was then released or reconstructed to locate the olecranon.

The posterior approach was used due to the presence of old scars in four patients. The incision was made along the previous posterior incision, and broad medial and lateral full thickness soft tissue flaps were elevated. Then, deep arthrolysis was performed as for the medial and lateral approaches. However, the lateral approach was also used to assist with anterior release in one of the four patients. Subcutaneous anterior transposition of the ulnar nerve was performed after neurolysis in all 15 patients.

At every step, the ROM was checked in order to decide whether to continue with the procedure. After each of the above steps, if satisfactory motion was not achieved, additional force was used to mobilize the elbow gently. The extra-articular contracture would be torn to some degree during passive movement. Then, if any soft tissue was obviously restricting the passive movement, a release was performed to gain terminal ranges. The anterior part of the medial collateral ligament (MCL) and the radial bundle of the lateral collateral ligament (LCL) should be left for elbow stability [4]. However, they were split by passive movement if they obviously restricted the ROM.

After achieving a satisfactory ROM (a range of 0° extension to 140° flexion, more than 50° in both pronation and supination), a hinged external fixator was fitted to the elbow without distraction. The important step in using a hinged external fixator was to identify the elbow rotational axis. The upper and the lower parts of the fixator were placed on the bones each side of the elbow. Then, after checking and documenting that the ROM was satisfactory, the muscle was reattached with atraumatic sutures and the wound was closed in layers.

Postoperative management

Patients were prescribed indomethacin (25 mg) three times a day for 4 weeks. A program of exercise was devised, involving a cycle of exercises of flexion and extension. The exercises were gradually increased to include active and passive exercises twice a day for half an hour each time, and patients were instructed to sleep with the elbow alternately positioned in as much flexion or extension as possible. Patients were expected to gain at least 90 % of the ROM during the first week after surgery. In subsequent weeks, the time of rehabilitation gradually increased to 1 h sessions. The hinged external fixator was removed 6–8 weeks after arthrolysis, as an outpatient procedure without anesthesia.

Results

Satisfactory follow-up was provided to all patients with a mean duration of 31.1 months (range 24–49 months). The total ROM of the elbow improved from a preoperative 0° to a postoperative mean of 115.7° (range 60 –145°). The final range of flexion to extension of the elbow was 10.3° (0°–30°) to 126.0° (90°–145°). The Mayo Elbow Performance Score improved from a mean of 67.67 ± 11.00 to 86.67 ± 8.38 points (t = −6.862; p < 0.001), with excellent results in nine patients, good in five, and fair in one [5]. Although more or less recurrent HO was observed in three patients within 3 months postoperatively, the HO was mature and did not affect the elbow function at 6 months follow-up. One patient had valgus instability but was able to adapt to this through muscle control and activity modification. All four patients with preoperative ulnar neurapraxia were regaining sensibility after transposition at 12 months follow-up, and no other patient complained of paresthesia of the ulnar nerve postoperatively. In two patients, superficial pin tract infection occurred. The resulting local infection was controlled with wound care until the pins were removed. Figures 5,6,7,8, and 9 show the postoperative elbow ROM and imaging of the case 7 in our series.

Fig. 5
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Rehabilitation of extension with fixator was performed 3 days after surgery

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Fig. 6
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Rehabilitation of flexion with fixator was performed 3 days after surgery

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Fig. 7
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The elbow function of extension restored 20 months after surgery

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Fig. 8
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The elbow function of flexion restored 20 months after surgery

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Fig. 9
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Lateral and AP radiographs show HO was removed and not recurrent at follow-ups

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Discussion

Only a few techniques have been described for the surgical release of a very severe stiff elbow, especially for the one which is ankylosed [6, 7]. Ring and Jupiter [6] reported an average ROM gain of 81° in a burn cohort and 94° in a trauma cohort in their series of ankylosed elbows. Kulkarni et al. [7] previously reported their experience using radical arthrolysis via twin incisions with the use of a monolateral hinged fixator to treat very severe extra-articular contracture of the elbow with an arc <30°, and their results demonstrated a post-operative mean improvement of the arc to 102°. This study presents the results of open arthrolysis and hinged external fixation, in terms of elbow joint function, for patients who had a posttraumatic ankylosed elbow with a ROM of 0°. Complete arthrolysis was used to release any pathology blocking the movement, while hinged external fixation was used for complication control. As a result, the functional outcome was satisfactory with controlled complications.

Complete arthrolysis of any pathology is the first consideration. Arthrolysis of a stiff elbow can be performed by several approaches [4, 8, 9]. The position of any old incision scars and the location of the pathologies are taken into consideration to determine the approach [10, 11]. In our opinion, a combination of lateral and medial approaches may be a good technique for exposing the ankylosed elbow. This surgical approach to the elbow provides an adequate exposure while preserving the neurovascular structures. Our concept of protecting the sulnar nerve by open debridement through combined approach echoes an earlier study by Lee AT [12]. Moreover, this technique allows a complete soft-tissue release, a remobilization of loose bodies in the coronoid fossae, prevention of subsequent instability by preserving the important bundle of the LCL and MCL, early postoperative exercises and fewer wound problems [1, 3, 13–16]. Consequently, in our series, eleven patients underwent arthrolysis by medial and lateral approaches, resulting in satisfactory outcomes and fewer wound problems. The posterior approach was also considered because bilateral aspects of the elbow can be explored by a single incision. However, patients often experience pain due to the posterior incision when they perform flexion exercises. The posterior incision was applied in four patients in our series due to the presence of old incision scars and the location of the pathologies. However, the posterior approach did not allow sufficient exposure of the anterior aspect in one case, as a result, this was combined with a lateral approach. In our study, if a posterior approach was planned, to reduce the tension in the soft tissues after surgery and enable the exercises to be performed, patients were asked to pull the skin around their elbow preoperatively.

If satisfactory motion was not achieved after basic excision and release, in our opinion, it was very important that passive movement should be performed to mobilize the elbow gently during surgery. The crucial bundles of the LCL and MCL were preserved as much as possible to prevent subsequent instability [17]. However, we recommend splitting them by passive movement rather than sharp incision if they restrict the ROM. After splitting rather than resection of the ligaments, the collateral ligaments usually heal if the elbow is kept reduced, and thus the permanent stability may be gained after removing the external fixator [18]. The rationale for intraoperative passive movement with additional force is (1) to preserve some bundles of the LCL and MCL, because then only tensioned bundles will be split during flexion or extension and, (2) to increase collateral ligament healing following blunt splitting. In this study, our chosen method was validated by the satisfactory ROM and controlled complication rate that was achieved.

Hinged external fixation provides additional protection from complications. It has been proven to provide stability following extensive release and to maintain early motion [11, 19, 20].In cases involving an ankylosed elbow undergoing complete arthrolysis, instability is a significant potential problem. The posttraumatic collateral ligaments may be insufficient to maintain stability, because the collateral ligaments are sometimes ossified and thus are excised [16]. Thereafter, hinged external fixation can, and ideally should, be performed in ankylosed elbows. Whether hinged external fixation improves the ROM after contracture release remains controversial [2, 3, 7, 11, 20]. Nevertheless, we believe that external fixation is very helpful for rehabilitation because of the increased ability to perform early motion and to maintain the ROM gained during surgery. Furthermore, the early mobilization after arthrolysis may prevent the HO formation according to the study of Bauer and colleagues [21]. Compared with the primary prophylaxis against HO which may interfere with tissue healing, the early mobilization after releasing with the help of external fixation seems reasonable. As a result, only one film instability was detected in our series with satisfactory results.

Forthman [22] believed that the ulnar nerve should be freed from any scar tissue and transposed when preoperative nerve dysfunction was found or when significantly more elbow flexion was expected postoperatively. In our series, all four patients suffering from preoperative ulnar paresthesia returned to normal after undergoing nerve transposition, and no other patient complained of paresthesia of the ulnar nerve postoperatively. Consequently, anterior transposition of the ulnar nerve applied routinely may significantly reduce the morbidity of the neuropathy, as the previous study demonstrated [6, 23, 24].

From our results we can conclude that open arthrolysis and use of a monolateral hinged external fixator are effective in cases of complete ankylosis of the posttraumatic elbow with a ROM of 0°. We recommend that arthrolysis should be performed by a combination of lateral and medial approaches. In addition, routine hinged external fixation and anterior transposition of the ulnar nerve may have benefits with respect to postoperative recovery of elbow stiffness.