Clinical presentation.

An individual with a scaphoid nonunion commonly presents with long-lasting mild or dull pain on the radial side of the wrist, with pain aggravation during daily use or with wrist weight-bearing. Limited wrist motion is common. However, some patients with nonunion may present with very mild pain or pain that does not interfere with daily use because of the pseudoarticulation that has formed between the two segments of the fractured scaphoid. The most common clinical signs are tenderness in the anatomic snuff box or at the scaphoid tubercle, dorsal swelling, and decreased grip strength. ^, In patients with a longstanding history of scaphoid nonunion and subsequent SNAC arthritis, pain can be severe and range of motion markedly reduced. These patients typically do not want to use the hand due to pain and loss of wrist functionality. However, some patients do not have any pain.

Diagnostic tools: Nonunion.

The diagnosis of scaphoid nonunion relies on x-rays findings. Clinical presentation alone cannot confirm the diagnosis. Therefore plain radiographs and, often, CT are necessary for patients with a history of acute scaphoid fracture and prolonged clinical problems after treatment or without timely treatment.

Plain radiographs include posteroanterior (PA), lateral, and scaphoid views. Scaphoid-view radiographs can be made as PA radiographs taken with the wrist in ulnar deviation or oblique view with 45% of pronation. Stecher projection with closed fist and ulnar inclination of the wrist may provide additional information.

In plain radiographs, displacement of the fracture segments and humpback deformity (defined as having a lateral intrascaphoid angle of >45 degrees) should be sought. Sclerosis, cystic changes, and areas of bone resorption are often present, but they are not reliable to predict vascularity. These signs of nonunion may not be evident for several months after the initial injury or treatment, although clinical presentation indicates the possibility of development of nonunion. Therefore clinical follow-up and repeat plain radiographs are often necessary.

CT scans provide more detail and more accurate information regarding the nonunion ( Fig. 9.1 ). CT scans may show osseous resorption zones along the fracture line, as well as adjacent pseudocystic inclusions in the scaphoid fragments. CT can help detect these changes earlier and with finer morphologic details. The nonunion cleft often appears larger than what is shown in plain radiographs. Displacement and instability are important risk factors for nonunion of scaphoid fractures. Several measurements in CT scans, such as the lateral intrascaphoid angle or the height to length ratio, may be useful in preoperative planning. ^,

Sagittal reformations of CT scans of (A) a nondisplaced and (B) a displaced scaphoid fracture. Gapping and angular deformity are seen in (B) as signs of instability and more likely progress to nonunion.

Increased density (sclerosis) of the proximal pole and absence of converging trabeculae between the fracture fragments on CT may correlate with intraoperative and histologic evidence of AVN, although some investigators do not find such correlation of CT with histology. The analysis of the complex shape of the scaphoid needs 3D reconstructions, and the uninjured contralateral side can be imaged for comparison. ^, Three-dimensional CT imaging is helpful to distinguish stable from unstable fractures ( Figs. 9.2 and 9.3 ).

Scaphoid nonunion of a 16-year-old patient visualized with different imaging modalities. (A) In the conventional x-ray (Stecher view), the nonunion is not always easy to see and is hard to analyze because it is a 2D summation image. (B) Better visualization of the nonunion and assessment of bone structure can be obtained with 2D CT reformations like the presented image in the sagittal plane. (C) 3D CT imaging is best suited for analyzing deformity, fracture plane, and fracture location in relation to relevant anatomical landmarks (stability and vascularity). In this case, the fracture lies distal to the dorsal apex (asterisk) , indicating an unstable nonunion that is confirmed by the dislocation of scaphoid fragments.

Left scaphoid nonunion in the middle third with rotational malalignment seen with 3D CT reconstructions.

MRI is useful in detecting hidden fractures. MRI was reported to assess the vascularity of the proximal pole, ^, but it may be unreliable. With an unenhanced MRI, normal bone viability has a high signal intensity. Hypointense areas of bone in T1 and T2 weighted sequences may indicate AVN, but they may also indicate ischemia and even viable bone. ^, Contrast-enhanced MRI has been found to have higher sensibility in detection of AVN compared with nonenhanced MRI. However, ingrowth of nonspecific inflammatory tissue into the proximal pole from the nonunion site results in contrast enhancement despite the necrotic nature of the bone. ^,

Diagnostic tools: AVN.

AVN, occurring in some scaphoid nonunions, is easy to suspect, and yet hard to ascertain. In plain radiographs, remarkably increased density of bone in plain radiographs suggests AVN, but that is uncertain. In MRI, hypointense areas of bone may indicate AVN. It is debatable whether MRI findings accurately diagnose AVN. Therefore MRI findings should be interpreted with great care. It is generally considered that MRI findings cannot indicate viability of the bone. Many colleagues do not rely on MRI to diagnose AVN. Intraoperatively, if the bone does not have punctate bleeding, AVN is likely, which is used popularly. Histologic analysis is reliable, but not feasible intraoperatively.

Internal fixation without bone grafting.

The most common surgery is open reduction, correction of humpback deformity with bone graft, and stable fixation. In minimally displaced or nondisplaced scaphoid nonunions, percutaneous screw fixation alone without bone grafting can be attempted ( Fig. 9.4 ). Rigid fixation without bone grafting can lead to bone healing in some patients. Hegazy et al reported 21 cases of scaphoid waist nonunions treated with percutaneous compression screw fixation without bone graft. Inclusion criteria were an intact cartilaginous envelope, minimal fracture line, no cyst or sclerosis, and no humpback deformity. However, internal fixation alone is not a commonly used method for treating scaphoid nonunions.

A 16-year-old patient with a delayed union in the proximal pole region 3 months after trauma as seen with (A) conventional x-rays and (B) 2D CT reformations. (C) Intraoperative arthroscopy showed no dislocation. (D) An antegrade screw fixation without bone grafting was performed.

A minimally invasive method of internal fixation with bone graft is an arthroscopically assisted percutaneous internal fixation with a headless compression screw inserted with a dorsal percutaneous technique. ^, This minimally invasive technique may prevent the complications of an open surgery and gives minimal surgical trauma to the blood supply and soft tissues. ^, However, this approach is technically demanding, and there are no comparative studies showing this approach is superior to the open approach. Therefore this approach remains unpopular.

Surgical approaches: Volar or dorsal.

Most surgeons prefer internal fixation through a volar or dorsal incision of approximately 4 to 5 cm. The volar approach preserves the dorsal blood supply and provides access to middle and distal third fractures with access to correct a humpback deformity. The dorsal approach provides improved exposure of the proximal pole with easier internal fixation placement, but it can disrupt the tenuous vascular supply. ^,

Debridement at the fracture site and bone grafting.

The nonunion site is accessed, and a thorough curettage is performed to debride the nonunion site. The soft fibrous union should be excised. The sclerotic surfaces of the two fracture segments should be removed until soft, healthy cancellous bone is exposed on both segments. The amount debrided will vary, but usually about 2 to 3 mm of such sclerotic bone should be removed to expose the healthy bony surface.

A variety of donor sites can be used, which is subject to personal preference. There is no conclusive evidence to indicate which donor site is best. The commonly used bone graft is cancellous bones from the distal radius, allograft of cancellous bone, vascularized bone graft from the distal radius (pedicled), or free vascularized bone graft from the ilium or knee area. See the text below for discussion of choice of donor sites and evidence to support the use of each. Nevertheless, the ideal donor site is unknown, and there is a question regarding the need of vascularized bone graft.

Choices of internal fixations: Compression screw versus kirschner wires.

After grafted bone is placed between the two fractured segments, rigid internal fixation is important ( Fig. 9.3 ). Headless compression screws and Kirschner (K) wires are commonly used methods of internal fixation. The screw is more commonly used. Some surgeons consider that K-wires alone may not ensure immobilization due to a lack of compression ( Fig. 9.5 ). However, using K-wires with bone grafting is preferred by some surgeons (including Jin Bo Tang), as they consider that compression does not favor nutrition including the blood supply and there is no basis for compression to the grafting bone. A systematic review in 2015 included 48 papers reporting on 1,602 patients with scaphoid nonunion. They were divided into subgroups according to different graft donors with screws (33 subgroups) or K-wire (27 subgroups) fixation. The authors did not find a significant difference, with union incidence of 88% for screws and 92% for K-wires, although patients with screw fixation were allowed to mobilize earlier. Among these patients, there were 125 proximal pole fractures with nonunions and AVN, among which 60 fractures were treated with screws for the grafts. The union incidence was 81% using screws and 97% using K-wires. Union incidence was encouragingly high given the traditional views that avascularity of the proximal pole is a poor prognostic indicator for scaphoid nonunion, although this view has been disputed. It appears that rigid fixation of the graft is more important than compression in treating scaphoid nonunion with a graft. It appears preferable to use K-wires in treating nonunions of the proximal pole with a graft because the proximal pole is small and may be fragmented during compression with screws, compressing the graft, and the proximal pole may further deprive synovial nutrition to the proximal pole and graft. Previous views on screws and compression were based largely on a metaanalysis two decades ago, which showed an improved union incidence of 94% with screw fixation compared with K-wire fixation of 77%. Despite attempts to advance the surgical management of scaphoid nonunion, approximately 10% persist after treatment.

Fixation techniques in scaphoid nonunions ranging from K-wires on the left , headless screw fixation in the middle , to plate osteosynthesis on the right .

Placement of a screw within the central third of the longitudinal axis of the scaphoid improves the stability of the fracture fixation. Preoperative 3D CT imaging may help precise screw placement ( Fig. 9.6 ). In selected cases, palmar angular stable plate fixation is an option. Leixnering et al reported a union of all 11 patients with scaphoid waist nonunions treated with plate fixation. Two of the authors (Rohit Arora and Gernot Schmidle) currently use such plating in cases of failed previous osteosynthesis, instability, bone defect, or short distal fragments ( Fig. 9.7 ).

Comparison of two scaphoid fractures of the middle third diagnosed with conventional x-ray imaging and correlated with postoperative 3D CT reconstructions. The fracture lines visible in the x-rays are marked with a white ellipse . The screws inserted retrograde along the long axis are colored blue . (A) In the first case, the distal fracture line projects into the middle third of the scaphoid, obscuring the proximal nature of the fracture with a steep fracture line. This leads to insufficient stabilization. (B) In the second case, the fracture runs obliquely in the middle third, which allows for good stabilization with the screw along the long axis.

(A) Example of a scaphoid nonunion with a short distal fragment and dorsal intercalated segment instability position as seen in conventional x-rays (scaphoid series). In this situation, screw purchase is limited and provides insufficient stability. (B) The nonunion is debrided and correct alignment is restored with the use of K-wires. (C) The bone defect is filled with a free corticocancellous bone graft from the iliac crest, and stability is restored with angular stable plating.

Distal radius versus iliac crest bone graft.

The common donor sites are distal radius and iliac crest. The union incidence and functional results of the techniques are equivalent. ^, The iliac crest graft has more donor site morbidity but seems to possess superior osteogenic properties compared to distal radius grafts. ^,

Corticocancellous versus cancellous graft.

An unstable scaphoid waist nonunion with humpback deformity is commonly treated with structural corticocancellous bone grafting and internal fixation. Cancellous bone grafting was originally used to treat stable nonunions without deformity. However, cancellous bone graft with rigid fixation shows comparable results with shorter interval to union. If the proximal and distal fragments are large enough, rigid screw or K-wire fixation can function as a strut, and cancellous bone grafting can be an option to treat unstable scaphoid nonunions. Sayegh and Strauch compared results of corticocancellous and cancellous grafts and found comparable healing incidence. Two of the authors (Rohit Arora, Gernot Schmidle) prefer plate fixation after corticocancellous bone graft because the proximal pole is often quite short and only a few screw threads can engage healthy tissue, jeopardizing stability ( Fig. 9.8 ). Additionally, the palmar plate works as a buttress against the humpback deformity.

(A) A 14-year-old patient with a right scaphoid nonunion with a short distal fragment and dorsal intercalated segment instability position. (B) The nonunion is debrided, and correct alignment is restored using the Linscheid maneuver. The wrist is flexed until the radiolunate angle is back to normal. The realignment of the extended lunate indirectly reduces the proximal scaphoid fragment via the intact scapholunate ligament. A percutaneous 1.6 mm radiolunate K-wire secures reduction. Wrist extension completes the reduction of the distal scaphoid fragment and restores scaphoid length. (C) The resulting bone defect is filled with a nonvascular corticocancellous bone graft from the iliac crest, and (D) stability is restored with angular plating.

The Matti-Russe procedure is the traditional technique and has recorded union incidence, but it has been associated with a high incidence of failure in cases of diminished or absence of punctate bleeding at surgery. With this technique, it is difficult to correct a humpback deformity. Therefore the Matti-Russe procedure is not commonly used nowadays.

A better method of graft placement is the Fisk-Fernandez technique, a method with good reported outcomes and union incidence. ^, The defect in the scaphoid waist or proximal pole is filled with a triangular or trapezoidal wedge-shaped bone graft, commonly obtained from the iliac crest. ^, This donor site is favored for patients with scaphoid nonunion and AVN of the proximal pole. ^, Matsuki et al treated 11 patients with an iliac bone graft and Herbert screw fixation for proximal pole nonunion, among which two patients had AVN. Healing was achieved in all patients, regardless of the vascularity of the proximal pole. In reporting a study of the Scaphoid Nonunion Consortium in 2018, Rancy et al followed 35 consecutive patients with scaphoid nonunions in a prospective longitudinal registry. All nonunions were treated with curettage, nonvascularized autogenous grafting, and headless screw fixation. Thirty-three of the 35 scaphoids healed by 12 weeks, with 30 having focal or robust remodeling activity and a 94% incidence of healing. Healing was defined as ≥50% bony bridging on CT images in the plane of the scaphoid. Among the 33 patients, nine patients had ischemia of the proximal pole but no infarction in preoperative MRI images, and 28 patients had impaired vascularity assessed intraoperatively. The authors concluded that proximal pole infarction is decidedly rare and that vascularized bone grafting is seldom required for a successful outcome with proximal pole nonunions.

Pedicled bone from dorsal distal radius.

Pedicled vascularized bone grafts from the distal end of the radius have many potential benefits. The corticocancellous bone can replace the deficient bone stock at the nonunion site and provide structural support ( Fig. 9.9 ). ^, This is a popular method used by many hand surgeons because the graft is easy to harvest and only one surgical field is required for grafting and internally fixing the scaphoid fracture. The surgical outcomes are generally satisfactory.

(A) X-rays of a right proximal scaphoid nonunion without angular deformity. (B) Dorsal view with prepared bed for a pedicled vascularized graft from the distal radius. (C) Shows the elevated graft based on the 1,2 intercompartmental supraretinacular artery (D) that is fit into the defect. (E) Postoperative x-rays after screw fixation and filling of the grafting site with chronOS™ bone graft substitute.

Fibrous tissue and any avascular bone in the nonunion site are curetted. Most often, the graft from the distal radius is harvested based on 1,2-intercompartmental supraretinacular artery (1,2-ICSRA). This artery is dissected through a dorsal curvilinear incision to expose the first and second extensor compartments. The 1,2-ICSRA vessel overlies the extensor retinaculum between the two compartments. The periosteum with cortical bone and underlying cancellous bone are harvested with preservation of the artery pedicle and a 5-mm cuff around the vessel to allow venous return. The size of the bone to harvest depends on the defect in scaphoid to fill, and additional nonvascularized distal radius cancellous bone graft is used when necessary. After surgery, the patient is placed into a long-arm splint or cast, followed by casting and/or splinting until radiographic union. The 2,3-intercompartmental supraretinacular artery (2,3-ICSRA) pedicled bone graft can be used with similar surgical techniques, but the use of 2,3-ICSRA is less popular than 1,2-ICSRA.

In the presence of dorsal intercalated segmental instability (DISI) or AVN, this procedure may not work well. Chang et al reported union at an average of 16 weeks after surgery in 34 of 48 (71%) scaphoid nonunions treated between 1994 and 2003. Twenty-seven of the fractures were stabilized with cannulated screws, 15 with K-wires, four with both screws and K-wires, and three without internal fixation. The choice of internal fixation was made by the surgeon based on fragment size and stability. Failures in achieving union occurred in 9 of 14 (64%) fractures with DISI and/or humpback deformity. In proximal scaphoid fractures with proximal pole AVN, 5 of 8 fractures with screw fixation and 2 of 4 with K-wire fixation had union; the overall union incidence was 50%. Chang et al and other surgeons consider that the 1,2-ICSRA is not a suitable option for the treatment of scaphoid nonunion with DISI or with AVN of the proximal pole.

Although these grafts are usually placed as dorsal inlay grafts, they also have been successfully used as trapezoidal volar intercalated grafts. Henry reported union in all 15 patients at a mean of 11.5 weeks after surgery. All patients had humpback deformity and proximal pole AVN as diagnosed by MRI and intraoperative inspection.

Vascularized volar distal radius graft.

A pedicled graft from the volar aspect of the distal end of the radius has been described by Kuhlmann et al. With this technique, a structural interposition graft to correct the humpback deformity can be harvested. Grafts from the volar ulnar side of the distal radius have higher structural stability and have successfully been used to correct deformity ( Fig. 9.10 ). Dialiana et al and Gras and Mathoulin have reported favorable outcomes in union, correction of carpal malalignment, and restoration of scaphoid length. ^,

Volar distal radius bone as the donor site. The volar distal radius is vascularized with volar carpal artery of the radial artery (A), or a branch from the ulnar artery (B). A pedicled bone graft can be harvested to treat scaphoid nonunion.

Free vascularized iliac crest graft.

Pechlaner et al used a free vascularized bone graft from the iliac crest based on its vascular pedicle and anastomosed to the radial artery ( Fig. 9.11 ). Gabl et al reported union in 12 of 15 patients with proximal pole AVN after this graft. The lead author and colleagues treated 21 patients who had failed prior procedures or MRI evidence of AVN, which was confirmed intraoperatively; 16 patients (76%) achieved union. Harpf et al reported 60 cases of scaphoid nonunion (21 with AVN) treated by this graft with union incidence of 92%.

Vascularized bone grafting from the right iliac crest. (A) The iliac crest is outlined with dotted lines . The planned harvest site is marked with two parallel lines approximately 3 cm proximal to the anterior superior iliac spine (crescent-shaped marking) . The surgical approach is slightly medial to the iliac crest for better access to the deep circumflex iliac artery (DCIA). (B) Dissection of the oblique abdominal muscles (C) until the DCIA can be identified in the layer between internal oblique and transverse abdominal muscles. The actual branches reaching to the iliac crest (white arrows) are identified and harvested together with the surrounding soft tissues as excessive dissection would jeopardize these fragile vessels. (D) Centered on the nutrient vessels, a bicortical graft is taken. Alternatively taking a tricortical graft makes the procedure technically easier and increases pedicle safety.

Free vascularized medial femoral condyle graft.

The medial femoral condyle (MFC) can treat the scaphoid nonunion in the setting of AVN and correct the humpback deformity and carpal collapse ( Fig. 9.12 ). The MFC graft is corticocancellous and uses either the longitudinal branch of the descending geniculate artery and vein or the superomedial genicular vessels. The lead author and colleagues evaluated the use of a MFC graft with and without cartilage in 37 patients with recalcitrant scaphoid nonunion with a specific focus on union rates and proximal pole destruction. Our results showed a union rate of 95% and good functional outcomes. Doi et al used vascularized MFCs as volar inlay grafts and achieved union in all 10 patients with AVN of the proximal pole at an average of 12 weeks after surgery. Jones et al reported successful use of the free vascularized MFC graft in scaphoid nonunion with AVN and humpback deformity with failed previous surgery with union in all cases.

(A) The medial femoral condyle graft is harvested with the ipsilateral knee in slight flexion and abduction to access the donor site. The femur, patella, and tibiofemoral joint line are identified. An 8 to 10 cm incision is centered on the distal medial thigh along the midaxis of the femur. (B) The fascia of the vastus medialis is incised dorsally, and the muscle is elevated from posterior to anterior. This exposes the descending genicular artery with its periosteal extensions. In most cases, a longitudinal branch for conventional grafts and a transverse branch running anteriorly for osteochondral grafting can be identified. (C) The area used for bone grafting is determined, and the pedicle is dissected proximally. An oscillating saw and osteotomes are used to harvest the bone graft. (D) The graft is tailored in a shoe-like fashion to match the excavated proximal pole fragment. (E) For fixation we prefer a single titanium K-wire. (F) The pedicle is sutured end-to-side to the radial artery or, if feasible, end-to-end to the superficial volar branch of the radial artery. We never perform a venous anastomosis. (G) Patency is checked by the milking test and ICG (indocyanine green) videography. (H) Vascularity of the donor bone (femoral condyle).

Another study compared the use of MFC graft as a structural interposition graft and the use of distal radius pedicled vascularized graft (1,2-ICSRA) in cases of scaphoid nonunion with proximal pole AVN and humpback deformity. All 12 patients treated with the MFC graft healed and had significantly improved postoperative carpal angles. In contrast, in 10 patients treated with the 1,2-ICSRA, only four patients gained union but failed to show improved carpal alignment. Especially in longstanding nonunion with failed screw fixation, the lead author prefers to use a vascularized MFC graft. In these cases, the proximal pole already has bone loss because of the implanted screw. Additionally, the blood supply is compromised by the surgical approach.

Vascularized osteochondral medial femoral graft.

An osteochondral MFC graft includes articular cartilage from the medial femoral trochlea ( Fig. 9.13 ). It can be used for a variety of indications and procedures, including replacement of the entire proximal part of the scaphoid and successful reconstruction and restoration of carpal alignment.

An osteochondral vascularized graft from the medial femoral condyle. The images show (A) the excised fragmented proximal pole, (B) the debrided scaphoid with a prepositioned K-wire for further fixation, and (C) the harvested vascularized osteochondral graft.

Studies directly comparing vascularized and conventional grafts are scarce.

Although there are many studies focusing on either vascularized or nonvascularized bone graft as the treatment, studies directly comparing vascularized and conventional grafts are scarce. In 2004, Munk and Larsen reported a metaanalysis of 147 articles on 5,249 scaphoid nonunions. Eighty-four percent of the patients treated with nonvascularized bone grafting with internal fixation achieved union with an average immobilization of seven weeks, and 91% of those treated with vascularized bone grafting with or without internal fixation healed at 10 weeks.

In 2016, Ferguson et al reported a systematic review examining 144 articles with 5,464 scaphoid nonunions. They reported an 84% union incidence for vascularized bone grafting (904 patients) and 80% for nonvascularized bone grafting (3,971 patients). In the presence of AVN (543 patients), the incidence of union was 74% for vascularized bone grafting and 62% for nonvascularized bone grafting. AVN was diagnosed in 40 studies in several ways, including radiography, MRI, and punctate bleeding. Union incidence varied considerably. They found the need for high-level evidence.

Ribak et al prospectively randomized 86 scaphoid nonunion patients into groups treated with either distal radius vascularized bone grafting or nonvascularized bone grafting with K-wire fixation. Union was achieved in 89% in the vascularized graft group and 73% in the nonvascularized graft group, a statistically significant difference. Proximal pole AVN was assessed by intraoperative punctate bleeding. In the AVN subgroup, union incidence was 83% with vascularized bone grafting contrasted to 55% with nonvascularized bone grafting.

In the institute of one of us (Ruby Grewal), a clinical trial randomized patients to receive a pedicled vascularized bone graft (28 patients) based on the 1,2-ICSA or a nonvascularized iliac crest graft (22 patients). All had K-wire fixation. Thirty-eight patients were available for union assessment and 23 for clinical measurements. No significant differences were found in union incidence, time to union, complications, patient-reported outcome scores, or wrist mobility and grip strength between the groups. Smokers were 60% less likely to achieve union. When controlling for smoking, patients receiving a vascularized graft were 72% more likely to achieve union.

Additional donor sites and surgical methods.

Corticocancellous bone from the olecranon can be easily accessed through a longitudinal incision in the same surgical field that is used to treat scaphoid injury. Bone substitutes may also be used, although the effectiveness in treating scaphoid nonunion has not been assessed. Vascularized corticocancellous graft from the radius (about 1 × 1 cm) attaching to a capsular flap of the dorsal wrist capsule (of about 2 cm long) is another method. ^, The graft is harvested from the distal radius ulnar to Lister’s tubercle about 2 cm proximal to the articular surface and can include the dorsal ridge of the distal radius. After fixation of the scaphoid with a cannulated screw, the graft is press-fit into the scaphoid nonunion site. Vascularized bone graft from the base of the second metacarpal or third metacarpal base with a dorsal carpal capsule strip can also be used.

Osteochondral autograft transplantation.

If the proximal pole is fragmented or necrotic, an osteochondral graft from the MFC offers a favorable solution for proximal pole replacement. Weber et al reported eight patients who underwent osteochondral autograft transplantation (OAT) harvested from the medial or lateral trochlea at an average of 18 months after injury. Four patients had failed prior attempts at scaphoid union surgery, one of whom failed two prior surgeries. Four had no prior surgery. In the procedure, a plug was taken from the medial femoral trochlea, offering a hyaline cartilage surface. The underlying subchondral bone was harvested with the cartilage, which should assist in healing. The plug was pressed to fit into the scaphoid without hardware. The average follow-up was 12 months. All eight OATs healed. CT scan confirmed union in six patients between 6 and 10 weeks. OAT is an attractive procedure for patients with proximal pole scaphoid nonunions associated with an intact scapholunate ligament. This procedure mitigates the need for vascularized bone grafting.

Vascularized medial femoral osteocartilaginous flap has demonstrated successful outcomes in treating scaphoid proximal pole nonunion with a high union rate and restoration of functional range of motion and grip strength. ^, This procedure, however, is lengthy and technically demanding and may not improve the union rate compared with nonvascularized options. Nonvascularized autograft arthroplasty, such as rib or hamate autograft, has demonstrated encouraging outcomes but still requires prolonged postoperative immobilization and a return to the operating room at around 8 weeks for the removal of K-wires.

Prosthetic replacement of the scaphoid proximal pole with an adaptive proximal scaphoid implant has been shown to prevent SNAC and to have high clinical satisfaction and fast return to sport and work. However, failure was reported in 12%, with persistent pain and/or loss of grip strength. Dislocation was reported in 4%, and long-term outcomes are lacking. This technique does not correct carpal collapse and is indicated only when the proximal pole can be excised without injuring the scapholunate ligament. It should be known that OAT does not provide the structure necessary to correct and resist carpal collapse. This procedure is to restore cartilage alone. In cases where bone and cartilage reconstruction is necessary, where there is scaphoid collapse or scapholunate ligament injury, or where the proximal fragment is too large to excise without compromising scapholunate stability, an alternative procedure is indicated. This could be a vascularized bone graft, a proximal hamate autograft, or a rib osteochondral graft as described below.

Proximal hamate autograft.

The proximal hamate autograft is a relatively new option. The ipsilateral hamate is harvested as an osteochondral graft in the size of the defect to be replaced together with the adhering portions of the volar capitohamate ligament. The proximal pole of the hamate can also serve as a replacement arthroplasty in the setting of proximal pole scaphoid nonunions with collapse, bone loss, and/or osteonecrosis. This graft may address shortcomings of other graft choices by providing a local structural autograft solution with minimal donor site morbidity and with the opportunity to correct carpal collapse and reconstruct the scapholunate ligament without the need of microvascular anastomosis.

Rib osteochondral grafts.

Rib osteochondral grafts have also been described. ^, Descriptions vary regarding the harvesting site, and fixation is carried out with K-wires, as screws tend to split the graft during insertion. Good results have been reported, but these procedures are burdened with an unfavorable donor site. In the experience of one of the authors (Toshiyasu Nakamura), the donor site problem for this procedure is quite minimal. Veitch et al reviewed 14 patients with deficiency of the proximal pole of the scaphoid who were treated by rib osteochondral replacement arthroplasty. Improvement in wrist function occurred in all except one patient. The authors reported that this procedure can restore the mechanical integrity of the proximal pole of the scaphoid and maintain wrist movement while avoiding the potential complications of alternative replacement arthroplasty techniques and the problems associated with vascularized grafts and salvage techniques. Interested colleagues should go to the cited references for surgical methods and tips from the surgeons who have performed the procedures.