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Corresponding author. Department of Orthopedics, 6th floor, MS Building, Seth GS Medical College and KEM Hospital, Acharya Donde Marg, Parel, Mumbai-12, India.
Occurrence of HOTL is common in shoulder and spine. HOTL of the annular ligament is very rare yet it can occur.
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HOTL of the annular ligament can obstruct the reduction of radial head in a neglected monteggia fracture.
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Though reports of regression of HOTL of the annular ligament with ulnar osteotomy is reported, simple excision and reconstruction can lead to a fully functional elbow.
Abstract
Heterotopic Osification (HO) commonly occurs in the hip and elbow joint post, trauma, surgery or dislocation. HO can occur anywhere in the body, and the term Heterotopic Ossification of Ligaments and Tendon (HOTL) is specifically used to denote HO occurring in ligaments and tendons. HOTL of an annular ligament is reported rarely in the literature. Here we describe a case of calcified annular ligament in a neglected monteggia fracture (Bado Type – 1), which was managed by excision and reconstruction of the same using triceps fascia. Post-op review after 2.5 years showed a stable elbow, with some restriction in pronation.
HO can occur anywhere in the body including skin, muscles, tendons and in viscera like mesentery. Even HO occurring in peripheral nerves are reported (neuritis ossifications).
The term Heterotopic Ossifications of Tendons and Ligaments (HOTL) is used specifically to denote ectopic mineralization of ligaments and tendons. The basic pathology of HO/HOTL is enchondral ossification and no proper treatment is available for the same.
While literature explaining the occurrence of HO in Hip, elbow and other areas are well defined, very few literatures are available about HOTL of the annular ligament and its management. Here we describe a rare case of HOTL of the annular ligament and the way it was managed.
2. Case presentation
14-year-old female child presented to us with swelling in the anterior aspect of the elbow joint and decreased Range Of Movements (ROM). The patient had sustained an injury to the left elbow while playing 6 months back and was managed with an above elbow slab for 2 weeks followed by physiotherapy, from an outside hospital. Physiotherapy failed to improve elbow range and hence the patient presented to us. Initial evaluation showed a palpable radial head anterior to the plane of lateral epicondyle. Supination was minimally restricted but protonation was decreased by 40° when compared with the normal side (Fig. 1). With careful palpation, a separate firm mass was palpable anterior to the radial head, which did not move with protonation or supination. Palpation of the rest of the forearm was insignificant and no other swelling was palpable.
Fig. 1Image showing the restriction in protonation (400).
X-ray showed an anteriorly dislocated radial head, with minimal ventral angulation of the ulna suggestive of a neglected monteggia fracture (Bado type – 1) (Fig. 2). Additionally, there was a calcified mass, in the form of a shell sitting anterior to the radial head. This calcified mass appeared to be the annular ligament, from which the radial head must have slipped during dislocation. All other blood parameters were normal.
Fig. 2Anteroposterior (left) and lateral (right) Xray of the patient's elbow joint showing an anteriorly dislocated radial head with a mild anterior angulation of the ulna suggestive of a neglected monteggia fracture (Bado type – 1). Note the calcified annular ligament, which has migrated anterior and proximal to the radial head.
Initial plan was to remove the calcified annular ligament through Kocher's approach and do a reconstruction of the annular ligament and an ulnar osteotomy if required. An incision was taken over the lateral aspect of the elbow; elbow joint was explored through the interval between Extensor Carpi Ulnaris and Anconeus. Intraoperative findings include an anteriorly displaced radial head and a shell-like calcification anterior to the radial head, extending proximally into the radiocapitellar joint, suggesting a calcified annular ligament. The calcified annular ligament was shaped like a shell, measuring 1.5 × 1 cm and was attached to the anterior capsule. It had migrated anteriorly and proximally into the radiocapitellar joint space obstructing the reduction of the radial head. The annular ligament was resected en bloc (Fig. 3) and sent for histopathology. Post removal, the radial head reduced easily but was unstable. Reconstruction of the annular ligament with triceps fascia was planned. The incision was extended proximally over the posterior aspect of the arm, triceps fascia of 6 × 0.5 cm was resected in-situ with the distal stump kept attached to the olecranon. The proximal end was passed around the radial head and was sutured back to the distal stump forming a loop around the radial neck (Fig. 4). Post reconstruction, the radial head was stable through full arc of motion and there was no tightening of the reconstructed ligament and the radial head was stable, hence an ulnar osteotomy was not done. The wound was closed in layers and an above elbow slab was given.
Fig. 3The calcified annular ligament, a hard mass measuring 1.5 ∗ 1 cm and shaped like a shell.
Fig. 4Reconstruction of the annular ligament with triceps fascia, note the proximal free end passed around the radial head with the distal end still attached to the olecranon.
Once pain and swelling subsided, the patient was started with passive ROM in a hinged brace. Histopathology confirmed the calcified mass to be Heterotopic Ossification. Patient went on to recover with full flexion, extension and supination at 8 weeks with a 30-degree loss in pronation. A review at 2.5 years showed full ROM except for protonation which was restricted by 10-degree. There was no radial head subluxation and handgrip was equal on either side. (Fig. 5, Fig. 6).
Fig. 5Review X-ray after 2.5 years showing a reduced radial head.
Heterotopic Ossification is a well-known complication occurring in the elbow. Kaplan et al. described four factors necessary for the formation of HO, these include an inciting event, a signal agent, mesenchymal cells and an appropriate environment. The signal agent seems to play a significant role and the most common being the Bone Morphogenic Protein.
HO can be broadly divided into two forms 1) deposition of calcium directly (dystrophic ossification) 2) Cell-mediated - which requires the transformation of mesenchymal cells into osteoblast. In the 2nd variant, calcified mass formation occurs in the same way as routine bone formation i.e enchondral ossification (most common way for the formation of HO) and membranous ossification.
Two genetic variants of HO exists which include fibrodysplasia ossificans (FOP) (error in the intramembranous type of ossification) and Progressive Osseous Heteroplasia (POH) (error in the enchondral type of ossification). FOP has a poor prognosis, with most of the patients crippled by third decade. POH has a variable presentation, which ranges from superficial ossification to overlap with symptoms of Albright Hereditary Osteodystrophy.
HO usually presents with joint stiffness, limited ROM, warmth, swelling in the initial stage, which makes it difficult to differentiate from Deep Vein Thrombosis; these signs can develop 3–12 weeks post-injury. Serum calcium, phosphorus levels are usually normal and Alkaline Phosphatase, ESR and Creatinine kinase levels are elevated.
showed that USG could diagnose HO as early as 3 days after the onset of symptoms. The three-phase bone scintigraphy is the most sensitive imaging modality for the early detection of HO. MRI and CT have low specificity in the early stage.
The most common regions where HOTL occurs is the shoulder (Calcific tendinitis) and spine (Ossification of Posterior Longitudinal ligament). Ligament ossification follows a similar process as other HO - (1)trauma/injury, (2)inflammation – most important step, (3)mesenchymal cell recruitment, (4)chondrogenic differentiation and ossification.
Prevention and treatment for HO include many modalities, like low dose radiation, BMP inhibitors (Dorsomorphin), Bisphosphonates (used in both prevention and treatment of HO). Except for bisphosphonates, no other modality is effective in the treatment of HO, hence the preferred method is surgery.
The surgical options described for neglected monteggia include annular ligament reconstruction, ulnar osteotomy, ulnar osteotomy and annular ligament reconstruction, radial osteotomy, ulnar osteotomy and distraction with Illizaro.
Stable relocation of the radial head without annular ligament reconstruction using the Ilizarov technique to treat neglected Monteggia fracture: two case reports.
While many treatment options are available two important modalities commonly followed are 1)ulnar osteotomy with lengthening and 2)annular ligament reconstruction. The principle of Ulnar osteotomy is explained by Hayomi et al.
in their biomechanical evaluation. When there is no anterior ulnar angulation, even with sectioning of the annular ligament and the capsule of the elbow joint there was no significant anterior displacement of the radial head. However, with ulnar angulation (shortening) the displacement of the radial head increases proportionately with the degree of angulation. They concluded that ulnar angulation (shortening) decreases the radioulnar distance subsequently loosening the interosseous membrane and causing significant anterior displacement of the radial head. The principle behind the reconstruction of the annular ligament is that it prevents the anterior, posterior and lateral displacement of the radial head,
In acute injury, even with radial head displacement, the annular ligament is most likely to be intact, but it can get displaced in-between the radiocapitellar joint a similar scenario in our case too. In chronic cases (more than 4 weeks) the ligament usually gets absorbed and requires a reconstruction.
Our case had a dislocated radial head with a calcified annular ligament located in-between the radiocapitellar joint obstructing the reduction of radial head.
There are very few literatures available about the management of calcified annular ligament. Earwalker et al.
has reported 8 cases of anterior radial head dislocation, aged 6–13 years. 6 patients had plastic bowing of ulna and 2 patients had an ulnar fracture. The calcified annular ligaments varied in size and location, however, they grouped similar kind of calcification into 1) Major shell (5 patients), 2) Minor shell (1 patient), 3) Cuff around Radial neck (1 patient), 4) Proximally placed - calcification in between the radiocapitellar joint (1patient). Our patient radiological appearance was similar to that of a major shell, which is a capping calcification of the annular ligament over the volar aspect of the radial head. Prabhu et al.
described a neglected monteggia fracture with anteriorly displaced radial head. Though the author had not mentioned specifically about calcified annular ligament, the pre-op x-ray showed a calcified annular ligament, the appearance of which was similar to that of a proximally placed calcification. An ulnar osteotomy was done for the relocation of the radial head, they have reported removal of fibrous tissues in-between the radiocapitellar joint during surgery, but there was no mention about removal of any calcified tissue. Their follow-up x-ray, 1-year post-surgery showed almost complete regression of calcification. Earwalker case series showed gradual regression of the calcification with time in some cases, while some were lost to follow-up. They reported faster regression of the calcification with ulnar osteotomy (1-month post-surgery) in two patients.
Our case had HOTL of the annular ligament which is very rarely reported in literature and there is no literature regarding its proper management. We did a simple excision with a reconstruction of the annular ligament with triceps fascia, which led to a tremendous improvement in elbow ROM and a stable radial head. Mild restriction in protonation is a common complication among operated cases of neglected monteggia fracture.
Surgical treatment of chronic anterior radial head dislocations in missed Monteggia lesions in children: a rationale for treatment and pearls and pitfalls of surgery.
Stable relocation of the radial head without annular ligament reconstruction using the Ilizarov technique to treat neglected Monteggia fracture: two case reports.
Surgical treatment of chronic anterior radial head dislocations in missed Monteggia lesions in children: a rationale for treatment and pearls and pitfalls of surgery.
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