The Distal Radioulnar Joint

The distal radioulnar joint (DRUJ) is an area of growing interest. Work by Palmer (1987), Bower (1988), and others has provided us with a better understanding of the biomechanics of this complex region.

Many distal radius fractures involve the DRUJ. Displacement of the distal radial metaphysis without an associated ulnar shaft fracture must result in a partial or complete disruption of the distal radial ulnar articulation.

Fortunately, with reduction of the radius, the sig-moid notch usually realigns well with the ulna, and the problem is resolved. However, this cannot be taken for granted, as one of the most common problems in long-term follow-up of distal radius fractures relates to dysfunction of the DRUJ.

The distal radius is dealt with first, as described with any of the techniques above. The distal radial-ulnar articulation is then checked manually by assessing the anterior-posterior stability of the DRUJ in the operating room in full pronation, full supination, and midposition. If the joint glides well, and the distal ulna feels stable, no further intervention is needed. This is the case in the vast majority of patients. The presence or absence of an ulnar styloid fracture is of no consequence in this situation.

Radial Styloid Fracture Splint

Fig. 10.14. a,b A high-energy displaced intra-articular distal radius fracture in the dominant wrist of a 40-year-old surgeon. This is a combined type of fracture (AO C3.3) c,d After initial closed reduction, in plaster splint the overall position is marginal. The volar fragment remains displaced with an intra-articular step deformity.

Fig. 10.14. a,b A high-energy displaced intra-articular distal radius fracture in the dominant wrist of a 40-year-old surgeon. This is a combined type of fracture (AO C3.3) c,d After initial closed reduction, in plaster splint the overall position is marginal. The volar fragment remains displaced with an intra-articular step deformity.

If the ulnar head reduces in one position and feels stable (usually supination) yet is unstable or subluxated in another position, it is advisable to immobilize the arm and forearm with an above-elbow splint in the stable position. This is achieved using an above-elbow plaster splint, which is converted within days to a hinged cast-brace to facilitate elbow rehabilitation. It must be worn full time for 4-6 weeks to allow healing of the soft tissues of the DRUJ. An alternative is cross-pinning of the radius to the ulna in the reduced position. A large K-wire (2.0 mm) is used and is passed just proximal to the ulnar head, avoiding the articular cartilage of the sigmoid notch. Our preference for using the cast brace remains - provided the DRUJ is stable in supination.

Lastly, the soft tissue and bony damage may be such that the ulnar head is not stable in any position. This usually occurs with the combined multifrag-mentary fractures. In this situation two paths can be followed. If there is a small or no ulnar styloid fracture, the ulna is held reduced in the most stable position (supination, midpronation, etc.) and cross-pinned to the radius. Direct repair of the triangular fibrocartilage complex (TFCC) back to the ulnar styloid is possible, but sutures cannot afford enough strength to hold the repair without the tremendous torque of the forearm being neutralized by the ulnar-radial cross-pinning. The surgical approach for this repair is the same as that described below for reattaching the ulnar styloid. The TFCC is reat-tached to the base of the ulnar styloid with heavy f :\uf f :\uf

Fig. 10.14. (Continued) e-g Further details are seen with CT imaging. Note the volar displacement of the lunate facet fragment and the intra-articular location of a piece of the dorsal cortical bone on the CT scan images. h,i Following open reduction and internal fixation (ORIF) with the modular locked plating system, anatomy has been restored. The patient was able to return to performing surgery 3 months postinjury and regained full painless wrist and hand range of motion

Fig. 10.14. (Continued) e-g Further details are seen with CT imaging. Note the volar displacement of the lunate facet fragment and the intra-articular location of a piece of the dorsal cortical bone on the CT scan images. h,i Following open reduction and internal fixation (ORIF) with the modular locked plating system, anatomy has been restored. The patient was able to return to performing surgery 3 months postinjury and regained full painless wrist and hand range of motion nonabsorbable sutures that pass through the fibro-cartilage disk and anchor through drill holes in the ulna metaphysis.

In the presence of a moderate to large ulnar sty-loid fracture, the option to cross-pin is satisfactory. However, it has become our preference to perform a tension band wire repair of the ulnar styloid. This is performed through a separate incision, releasing the distal portion of the extensor carpi ulnaris (ECU) tendon and approaching the ulnar styloid directly through the floor of the extensor carpi ulnaris sheath. Care is needed to identify and preserve the dorsal sensory branch of the ulnar nerve in making the skin incision (Fig. 10.15). The fragment and with it the TFCC is reduced and held with a single 1.25mm K-wire. A small loop of 22-ga. stainless steel wire is passed through the ulnar carpal ligament portion of the TFCC, deep to the K-wire, and then secured through a small drill hole in the distal ulnar metaphysis. The wire is tightened by twisting it; double twists are not needed. The ulnar head shows remarkable stability after this simple repair. The forearm is immobilized postoperatively in the most stable position to protect this repair for 4-6 weeks. In a series performed by Axelrod and Cheng (1995), 11 of 12 patients treated with this technique showed a stable DRUJ with excellent restoration of pronation and supination; no nonunions of the ulnar sty-loid occurred.

Fig. 10.15a-e. Surgical technique for open reduction and internal fixation of the ulnar styloid process. a The incision is made along the ulnar side of the wrist, and care is taken to preserve the dorsal ulnar sensory nerve. b The extensor carpi ulnaris sheath is opened and the floor incised. The ulnar styloid fragment is found and left attached distally to the ulnar carpal ligament of the triangular fibrocartilage complex (TFCC). c The styloid is reduced and held with a 1.25-mm K-wire. A fine-gauge wire is passed through the ulnar carpal ligament and around the K-wire. It is looped into a drill hole in the ulna and tightened down. d Radiographs of a 44-year-old woman with a severe Galeazzi injury illustrating complete dislocation of the distal radioulnar joint. Following internal fixation of the radius, the DRUJ remained unstable in all planes. e Open reduction and tension band fixation of the ulnar styloid provided excellent DRUJ stabilization. Uneventful union of all fractures occurred in 8 weeks

Fig. 10.15a-e. Surgical technique for open reduction and internal fixation of the ulnar styloid process. a The incision is made along the ulnar side of the wrist, and care is taken to preserve the dorsal ulnar sensory nerve. b The extensor carpi ulnaris sheath is opened and the floor incised. The ulnar styloid fragment is found and left attached distally to the ulnar carpal ligament of the triangular fibrocartilage complex (TFCC). c The styloid is reduced and held with a 1.25-mm K-wire. A fine-gauge wire is passed through the ulnar carpal ligament and around the K-wire. It is looped into a drill hole in the ulna and tightened down. d Radiographs of a 44-year-old woman with a severe Galeazzi injury illustrating complete dislocation of the distal radioulnar joint. Following internal fixation of the radius, the DRUJ remained unstable in all planes. e Open reduction and tension band fixation of the ulnar styloid provided excellent DRUJ stabilization. Uneventful union of all fractures occurred in 8 weeks

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