The single-bone forearm is a salvage technique for massive loss of bone due to serious trauma, malignant tumors, infections or congenital deformity. It is also described to treat the sequelae of hereditary multiple exostoses disease that affects the distal end of the ulna. We present the case of a 29-year-old patient, operated for sequelae of hereditary multiple exostoses disease of the left forearm by a modified single-bone forearm technique. The patient, right-handed, operated on twice in childhood for a hereditary multiple exostoses disease of the left forearm: incomplete excision of the exostosis of the distal end of the ulna and lengthening of this last on external fixator, without improvement. The patient presented for a deformation of the left forearm with shortening compared to the right side‌. Significant limitation of prono-supination (pronation 15°, supination 20°). Elbow flexion at 110° and extension with deficit of 15°. Wrist flexion at 50° and extension at 50°, radial inclination at 25° and ulnar at 30°. The pain score was 3 according to the Visual Analogue Scale (VAS), especially on effort. Dash score was 31,82/100. We chose the forearm technique with a single bone. The immediate postoperative result found a realignment of the forearm, without neurological or vascular damages. Consolidation was obtained in four months. At five months, the patient recovered elbow flexion at 110° and full extension, wrist flexion at 45° and extension at 50°. Radial inclination at 20° and ulnar at 25°. The single-bone forearm technique has been described, not only for the treatment of hereditary multiple exostoses disease, but also for serious trauma or tumors with massive loss of bone. The technique generally consists of an osteotomy of the radius as well as the ulna, fixing the radius to the ulna creating a synostosis, with or without resection of part of one or both bones of the forearm. The most described complications of single-bone forearm procedure are pain, complications related to soft tissue secondary to the previous injury, and infections. The one-bone forearm remain a salvage technique for massive loss of bone of the forearm, or large deformities due to congenital malformations. This technique could allow the excision of massive bone and keep only a part of the ulna and the radius, with function maintenance and aesthetic forearm preservation.

Most malignant bone tumors are treated with surgical excision, adhering to oncologic principles, followed by reconstruction to preserve form and function whenever feasible. Primary bone tumors around the elbow are rare accounting for <1% of all skeletal tumors. They pose a reconstructive challenge, due to the complex interplay between the osseous & capsulo-ligamentous structures which is essential for elbow stability and function. Tumors affecting the proximal ulna are rare and reconstruction of the defects following these tumors is extremely challenging. Various reconstruction options like arthrodesis, autogenous bone grafts, allografts, re-implantation of sterilized tumor bone, pseudoarthrosis, and endoprosthesis have been tried with variable success. However, due to lack of standardization and the rarity of the site, surgeons are often in a dilemma to choose the correct option. This can lead to suboptimal functional outcomes and long-term failures. In this article, we reviewed the published literature on proximal ulnar tumors and noted the pros and cons of various reconstructive procedures. We have also attempted to formulate reconstruction recommendations based on the level of resection of proximal ulna.

The creation of a single-bone-forearm is a salvage procedure to stabilize the forearm. The purpose of this study was to investigate clinical outcomes and how these patients compensate for the lack of forearm rotation. We evaluated four patients (three children, one adult) who had undergone single-bone-forearm surgery. Patients were examined clinically and with three-dimensional motion analysis. We found these patients are generally capable to perform important activities of daily living (e.g. glass jug pouring), which would normally need forearm rotation. Motion analysis revealed remarkable compensatory motion at other joints during these activities. We conclude that patients with a single-bone-forearm can maintain a certain level of daily activities by using compensatory motions at other joints, although the time needed to complete the tasks may be longer. Level of evidence: IV.

Ulnar longitudinal deficiency (ULD) is a rare congenital disease of the upper limb. The deformities caused by ULD can be very challenging and may compromise hand function during daily activities. Although the first surgical intervention dates back to the year 1952 there is still no gold standard for treating this uncommon disorder. Two children aged 16 and 3 years with ULD Bayne Type II (partial ulna aplasia) were diagnosed and treated at our department with single bone forearm surgery to achieve stability and improve function using a modified surgical method. For the purpose of an additional gain in limb length and improved cosmesis we used an Ilizarov external fixator for soft tissue distraction including radius distalization prior to the creation of the single bone forearm. This new technique and results are presented and discussed.

Primary bone tumors around the elbow represent <1% of all the skeletal tumors. Surgery with or without adjuvant therapy (radiotherapy, chemotherapy) is the treatment of choice for malignant tumors. Reconstruction of the elbow and forearm in malignant tumors is challenging as it involves a complex interplay between multiple joints which need to be stabilized for the optimal functional outcome. We describe a new technique for the reconstruction of the elbow after resection of a proximal ulna tumor with articular radio-ulnar synostosis with the creation of a single bone forearm. We attempted to achieve a mobile elbow and stable wrist joint with the radio-ulnar union at the proximal articular surface of the ulna resulting in a single bone forearm. The procedure involves an oblique osteotomy preserving the olecranon process (after taking adequate margins based on oncological principles) and its articular cartilage along with the attachment of the triceps tendon. Then the radial head was partially denuded of its cartilage using a burr, leaving cartilage only on the volar side, and then fused to the remnant olecranon. Osteosynthesis was done using compression screw and tension band wiring. The advantages of this procedure are that the mobility at wrist and elbow are retained, it requires minimal hardware and allows for primary closure of the wound.

BACKGROUND: Radial bone loss associated with gross manus valgus deformity can be managed by open reduction internal fixation using intervening strut bone graft, callus distraction using ring or monoaxial fixator, and achieving union by distraction histogenesis. These methods are particularly suitable when bone loss is small. Single or staged procedure is described for congenital as well as in acquired extensive bone loss of radius. Distraction through radial proximal to distal segments, to achieve reduction of distal radio-ulnar joint (DRUJ), is also described in acquired cases. In the present series, functional results of distraction through ulna to 2(nd) metacarpal is studied alongwith, functional status of hand, stability of wrist, level of patient\'s satisfaction are also studied.
METHODS: 7 unilateral cases of radial loss (M = 5, F = 2) affecting 4 right hands of mean age 17 years (range 9 to 24 years) were included in this study. They were treated by distracting through ulna to 2(nd) metacarpal to achieve DRUJ alignment in first stage. Subsequently ulna was osteotomised and translated to distal stump of radius. It was then fixed to the distal radial remnant in 30° pronation in dominant and 30° supination non dominant hands.
RESULTS: Union was achieved in all cases associated with beneficial cross union of distal ulna. Hand functions improved near to normal, with fully corrected stable wrist joint, hypertrophied ulna and without recurrence. All of them had practically complete loss of forearm rotations, however patients were fully satisfied.
CONCLUSIONS: This method is particularly suitable when associated with 6 cm or more radial bone loss. But when loss is small, sacrifice of one bone may not be justifiable.