Surgical treatment options for this difficult problem are variable and can be quite challenging. As previously mentioned, while vascularized bone grafting may be attempted, it is not likely to be successful in such a chronic nonunion and in the setting of avascular necrosis. Additional options include partial scaphoid excision with and without soft-tissue interposition, scaphoidectomy and four-corner fusion, proximal row carpectomy , and proximal or complete scaphoid arthroplasty.

Given the absence of degenerative changes in the radiocarpal joint and the well-maintained overall carpal alignment, this patient was deemed a candidate for partial scaphoid replacement. The patient underwent proximal pole scaphoid arthroplasty. For this case, the adaptive proximal scaphoid implant (APSI; Tournier, Montbonnot Saint Martin, France) was utilized (Fig. 21.3). The implant is made of biologically inert pyrolytic carbon and has favorable wear characteristics. Its elastic modulus is similar to cortical bone, and animal studies have shown that it is biologically friendly to cartilage and bone. In addition, it is much stronger and more durable than silicone allowing for maintenance of carpal height and carpal alignment. Indications for proximal pole arthroplasty include an unsalvageable scaphoid, avascular necrosis, and collapse . The ideal patient would also have no evidence of arthritic changes in the scaphoid fossa of the radius and generally well maintained or minimal loss of carpal alignment.

The patient had excellent pain relief and improved strength and motion following surgery. Postoperative radiographs at 2 years following surgery are shown in Fig. 21.4. In addition to maintaining stable position, the carpal alignment was restored. He had no snuffbox pain. His grip strength improved to 35 kg, and the range-of-motion demonstrated a flexion–extension of 40° and 40° and radial–ulnar deviation of 10° and 25°, respectively. He was able to return to his employment without restriction.

Unsalvageable scaphoid nonunions with proximal pole avascular necrosis, sclerosis, and collapse pose a significant challenge for hand surgeons. Distal or proximal pole excision has been described in the past [1–4]. It is a relatively simple solution and straightforward rehabilitation for this difficult problem. Some investigators have reported encouraging early-term outcomes with this technique [2, 3]. However, problems with carpal malalignment and maintenance of carpal height resulting in recurrent pain and progression of arthritis may be a problem [2, 5, 6].

Partial and complete excision of the scaphoid with implant or soft-tissue arthroplasty has also been described for the unsalvageable scaphoid nonunion [7–16]. Complete scaphoid replacements include both silicone and metal materials. Inspired by A.T. Moore’s outcomes with hip hemiarthroplasty, a vitallium scaphoid arthroplasty was introduced in the 1940s [13, 17, 18]. While Legge [18] reported good outcomes in seven cases, Waugh and Reuling [17] felt that the results were too preliminary to make any conclusions in the three patients they treated. Leslie et al. reported a 43-year follow-up on a patient who underwent treatment with a vitallium scaphoid for unsalvageable nonunion [13]. While the implant remained quite stable radiographically and the patient had a functional range-of-motion, they also observed that the patient had pain and X-rays demonstrated significant erosion of the implant into the radius. Acrylic scaphoid replacements were introduced a short time later [19]. Like vitallium, preliminary outcomes were encouraging. Agerholm and Lee shared their experience with the acrylic scaphoid arthroplasty in a review of 16 patients followed between 1 and 8 years [20]. Despite the presence of pain in all but four cases, satisfactory motion, grip, and function were achieved in 14 of 16 wrists. While carpal collapse was present in five patients following surgery, it developed in only three cases compared to preoperative radiographs. Osteoarthritis was noted and graded as marked in five wrists, slight in six wrists, and absent in three. Two patients ultimately required implant removal. Agner published his experience with an acrylic silicone arthroplasty for scaphoid nonunion in seven cases with a 9- to 11-year follow-up [21]. Early improvement in range-of-motion was obtained in all cases. However, four patients were unable to return to work secondary to pain and another, despite early encouraging results, developed pain at 1 year following surgery. These five patients required removal of the implant. One of the two patients whose implant remained had radiographic evidence of severe arthritis 10 years following surgery with considerable pain. With only one case achieving a satisfactory outcome, the author was displeased with his experience.

Silicone scaphoid arthroplasty was introduced in the 1960s [22]. The premise of its use was in part secondary to the success with small-joint arthroplasty. The hope was that it would function more as a spacer and its material properties would minimize the progression of arthritis, yet be strong enough to maintain carpal alignment. Despite some encouraging preliminary reports, outcomes with silicone replacement for nonunion and scaphoid diseases have been generally poor [23–25]. Kleinert et al. published their experience with 33 patients who underwent treatment with silicone arthroplasty for the scaphoid with a 3-year average follow-up period [24]. Motion only improved slightly, and grip strength did not improve. Unfortunately, 13 (of 23 patients available for follow-up) went on to develop carpal collapse, and 9 of them had obvious subluxation of the spacer. Thirteen additional surgeries in ten patients were required. Smith et al. introduced us to the concerns associated with silicone synovitis with the carpal silicone implants [25]. A long-term clinical and radiographic analysis performed by Carter et al. demonstrated that 75 % of patients developed osseous changes and over half had significant pain associated with this problem [23].

As a result of complications associated with silicone, Swanson introduced a titanium scaphoid implant in the 1980s [16]. In their report, the authors outlined the indications and technique and shared their experience with 102 implants, among which 78 patients (85 wrists) were available for follow-up of an average 5.7 years. Forty-one of these were treated for scaphoid nonunion. Results demonstrated 97 % were extremely satisfied. Two developed arthritis and were revised to arthrodesis . One had persistent pain. The average wrist flexion–extension was 36° and 33°, respectively. Radial–ulnar deviation was 10° and 24°, respectively. Grip strength improved 40 % on average. Radiographs demonstrated that carpal alignment was well maintained and there were no significant osseous changes or problems related to the titanium alloy. Sixty-nine patients were able to return to pre-injury work activities. Spingardi and Rosello published their experience with the use of titanium scaphoid arthroplasty as well [15]. The authors examined 112 cases performed over a 15-year period, and they detailed the indications and their preferred technique along with outcomes. Seventy-five patients were available for follow-up analysis at an average 46-month follow-up interval. Clinical outcomes demonstrated nearly 75 % of patients had improved or functional flexion–extension arc of motion and the average grip strength was 80 % of contralateral side. 85 % of patients had no pain, 8 % had mild pain and 7 % had pain with activity, and all patients were able to return to their previous employment. Fifty-six (of 75) patients were considered to have a satisfactory or excellent result. The authors concluded that titanium scaphoid arthroplasty for unsalvageable nonunion , in the absence of arthritic changes, is a valid alternative to other salvage procedures.