Rationale and Basic Science Pertinent to the Procedure

Classically, management of a young patient with a step-off in the distal radius has been panarthrodesis. Several pioneer surgeons, such as Saffar,¹ Fernandez,² and others,^3–8 opened the door to the possibility of cutting again the displaced fragments and reducing them in anatomical position. The gold standard for the most common sagittal step (anteroposterior) is to do the osteotomy through a dorsal route partly under fluoroscopy guidance.^4,5,7,8 For volar shearing type malunions, the joint is approached volarly, the external callus is removed, and with an osteotome directed toward the joint, the fragment is slowly cut away, with the hope that the osteotome follows the original fracture line.^5,6,8 All these procedures and others can be grouped under “outside-in osteotomy techniques.”

Good results have been reported with outside-in osteotomy techniques, but fears of devascularization and inaccurate reduction exist. Fernandez² considered the technique appropriate only for single line fractures, although Gonzalez del Pino and Ring^4,5 used it for the more complex four-part fractures.

In my experience with outside-in osteotomy techniques, the main problem I had encountered was the difficulty having visual control of the step-off before the osteotomy, which became an “impossible” feat when the fragment was “reduced” as the joint space closed. One then had to rely on fluoroscopy (an unreliable method),⁹ and on palpation with a Freer elevator. Another problem was that sometimes the step-offs did not have a linear trace amenable to a simple cut, but rather a complex irregular shape (Fig. 57-1). To obtain better visual control, a very aggressive capsular release is necessary. This aggressive capsular release may increase the risk of avascular necrosis of the ostetomized fragments, virtually contraindicating outside-in techniques.

FIGURE 57-1 Preoperative computed tomography scan of a C3.1 fracture. A, A 3.5-mm step-off on the scaphoid fossa. A, anterior fragment; PC, posterior central fragment. B, Corresponding axial view of the same case, showing a multipiece fracture. The styloid (S), posterior central (PC) fragment, and small (i) intermiddle fragment are depressed, in relation to the anterior fragment (A) and the posteroulnar fragment (PU) (see C). C, Coronal computed tomography scan showing the depression of the styloid (S) and posterior central (PC) fragment in relation to the posteroulnar (PU) and anterior (A) fragments. Only the former fragments require correction.

(From del Piñal F, Garcia-Bernal FJ, Delgado J, et al: Correction of malunited intra-articular distal radius fractures with an inside-out osteotomy technique. J Hand Surg [Am]. 2006; 31:1029-1034; with permission from the American Society for Surgery of the Hand.)

Bearing in mind these limitations, we sought a method for assessing the status of the articular cartilage in the area of malunion, which at the same time allowed us to identify the fracture line accurately. This chapter outlines our present experience with a method to perform the osteotomy under arthroscopic guidance from “inside-out.”¹⁰

Indications

Any candidate for an outside-in osteotomy correction^1–7 can be eligible for an arthroscopic-guided osteotomy. Absolute indications are a malunion in the coronal plane (shearing-type fractures) causing secondary carpal subluxation and any fracture with a step-off of 2 mm or more, whether or not the patient is symptomatic. Some authors¹¹ believe that step-offs of just 1 mm also can be symptomatic, and it seems sensible in young patients with an intrafacetary step-off to go ahead with the operation. Low-demand patients or silent areas (e.g., the interfacetal sulcus) are better served by a conservative approach.

Timing is important, and delaying the operation would have a negative impact on the outcome in two ways. First, healthy areas of cartilage would wear out, particularly in intrafacetary step-offs.^2,12 Second, the operation would be technically more difficult, and the reduction obtained would be less accurate; this is because the gap would be filled with mature bone (rather than scarred bone and granulating tissue), making it more difficult to achieve reduction and to close the gap. Additionally, overzealous resection of tissue in the gap may cause narrowing of the radius in the frontal plane (see Fig. W9-5 online) causing ulnar translocation of the carpus.

Although my experience is limited to malunions less than 3.5 months old, I cannot see any contraindication in older malunions, provided that the cartilage is preserved. Surgical tactics vary slightly for older malunions (see later). Delaying the operation in the hope that some cases may not be symptomatic does not seem reasonable because midterm osteoarthritis has been shown to occur in most intra-articular malunions in young individuals.^13,14

Contraindications

Apart from the customary contraindications to any wrist arthroscopy (mainly active infection locally), I cannot see any reason for not trying to correct a malunited fragment or fragments if local conditions are met. Wearing out of the cartilage on the opposing carpal bone is a contraindication for the procedure because restoration of the joint congruency would not prevent osteoarthrosis in the short term. As discussed previously, intrafacetary malunions are probably tolerated worse than interfacetary malunions, but to contraindicate the procedure on timing alone is unwise. A patient with a huge step-off who has not moved the wrist much would wear the cartilage out less than a patient who has a small step-off but has undergone intensive physiotherapy. Another contraindication for this procedure is when an area of multifragmentation with scarring is found on the distal radius. In these cases, the patient would be better served with other options.

Surgical Technique

The surgical technique is more cumbersome and complicated than the average wrist arthroscopy.¹⁰ First, it requires an open exposure of the distal radius for plate fixation of the fragments in addition to the arthroscopic-aided osteotomy. Second, it requires alternating the hand from a suspended position to flat on the operating table. We use a custom-made system that allows easy fastening and release of the hand to and from the bow (Fig. 57-2).¹⁰ Third, fluoroscopy is used periodically during the procedure, which is facilitated by placing the hand flat. The osteotomes and probes that are used need to be sturdier than the average arthroscopic instruments (Fig. 57-3). Finally, the assistance of another experienced surgeon is integral to the procedure (Fig. 57-4). It is important that everyone on the surgical team is prepared and familiar with their assigned role to diminish the operative time because the whole procedure needs to be done in less than tourniquet time. It is helpful for the surgeon to preplan the osteotomies beforehand based on a review of the preoperative x-rays and, if possible, the original fracture films. I have found a good-quality preoperative computed tomography scan to be invaluable because the intraoperative view of the joint disruption can be quite misleading (see Fig. 57-1).

FIGURE 57-2 Method for maintaining sterility when changing from a vertical traction position, suitable for arthroscopy, to a standard surgical position, with the hand flat on the table. A, The hand, held with Chinese traps, hangs from “carabiner 1” (C#1), a figure-of-eight descender (F8), “carabiner 2” (C#2), and the “bow’s rope carabiner” (C#R). (Carabiners and figure-of-eight descenders can be purchased at any climbing shop.) B, The surgeon, under sterile conditions, connects C#2 to C#R, which is held by the operating room personnel. C, During arthroscopy, only the lower hole of F8 is considered sterile (F8-low) because the other hole (F8-top) comes into indirect contact with C#R. D, To transfer the hand to a horizontal position, the surgeon unfastens C#1. To put the hand into traction again, the surgeon needs only to fasten C#1 to F8-low, which maintains sterility at all times. All but C#R are sterile.

(From del Piñal F, Garcia-Bernal FJ, Delgado J, et al: Correction of malunited intra-articular distal radius fractures with an inside-out osteotomy technique. J Hand Surg [Am]. 2006; 31:1029-1034; with permission from the American Society for Surgery of the Hand.)

FIGURE 57-3 Instrumentation required for the procedure (from left to right): impactor, osteotome, strong angled curet, shoulder probe, small joint arthroscopic guide.

(From del Piñal F, Garcia-Bernal FJ, Delgado J, et al: Correction of malunited intra-articular distal radius fractures with an inside-out osteotomy technique. J Hand Surg [Am]. 2006; 31:1029-1034; with permission from the American Society for Surgery of the Hand.)

FIGURE 57-4 The setup. The first surgeon is controlling the reduction, while the second surgeon is stabilizing the reduction by introducing the distal pegs on the plate. A resident is holding the camera (Ass#1). The first surgeon has in front the arthroscopic tower and the fluoroscopy display.

(From del Piñal F: Correction of mal-united intraarticular distal radius fractures with an inside-out osteotomy technique. In Slutsky D, Nagle D, eds: Techniques in Wrist and Hand Arthoscopy. Elsevier, 2007.)

The key of the whole operation is to perform the arthroscopy without infusion water, which we have called “dry arthroscopy.”¹⁵