The Crucial Role of Locking Screws in Total Wrist Arthroplasty: Should We Always Revise or Not?

We report a rare case in which the entire capitate was replaced by free nonvascularized autologous bone grafting owing to a giant cell tumor. Moreover, a Maestro wrist prosthesis (second type) was subsequently implanted after two failed motion-preserving procedures. At the 6- and 8-year follow-ups, we observed complete but asymptomatic avascular bone necrosis around the entire capitate peg without evident failure of the carpal component. This case highlights the importance of locking screws in improving the longevity of total wrist arthroplasty by imitating external or internal fixation for bridging large bony defects in the long bones of the upper and lower extremities. However, loosening may occur in the future. To the best of our knowledge, this is the first report to describe an uncommon finding that cannot be solely attributed to the natural course of periprosthetic osteolysis. We report a rare case in which the entire capitate was replaced by free nonvascularized autologous bone grafting owing to a giant cell tumor. Moreover, a Maestro wrist prosthesis (second type) was subsequently implanted after two failed motion-preserving procedures. At the 6- and 8-year follow-ups, we observed complete but asymptomatic avascular bone necrosis around the entire capitate peg without evident failure of the carpal component. This case highlights the importance of locking screws in improving the longevity of total wrist arthroplasty by imitating external or internal fixation for bridging large bony defects in the long bones of the upper and lower extremities. However, loosening may occur in the future. To the best of our knowledge, this is the first report to describe an uncommon finding that cannot be solely attributed to the natural course of periprosthetic osteolysis. In 2016, we reported the unusual and complicated course of a giant cell tumor in the capitate. Two motion-preserving wrist procedures failed; therefore, a total wrist arthroplasty (TWA) utilizing a second Maestro type (two locking screws for fixation of the carpal component) was performed. At the 1-year follow-up, we reported encouraging short-term results with a high level of patient satisfaction.1Schmidt I. An unusual and complicated course of a giant cell tumor of the capitate bone.Case Rep Orthop. 2016; 20163705808Google Scholar Thereafter, an unpredictable bony finding developed that encircled the entire capitate peg and that may influence future decisions on the primary correct choice of an artificial wrist implant. For this reason, we would like to report on the current 8-year follow-up period. A 51-year-old woman presented with a Campanacci grade II giant cell tumor in the right capitate (Fig. 1A). Intralesional curettage and burring combined with cavity packing using cancellous iliac crest bone grafts and plate fusion of the third carpometacarpal joint was performed at another institution. At the first presentation at our hospital 1 year later, the patient reported increasing wrist pain. Radiographic and computed tomography scans revealed healing of the bone grafts but in the presence of pronounced bony destruction in the lunocapitate joint and a concomitant nonunioned scaphoid waist fracture without any known trauma (stress fracture) (Fig. 1B). Histopathological evaluation revealed no recurrence of the giant cell tumor but pronounced nonseptic osteoarthritis (OA); therefore, four-corner fusion with corticocancellous iliac crest bone grafts and two headless compression screws combined with excision of the entire scaphoid bone was performed. Another year later, one screw had migrated proximally, which led to erosion into the distal radius metaphysis, but both radiographic and computed tomography scans suggested complete osseointegration of the previously inserted iliac crest bone grafts (Fig. 1C). Therefore, TWA utilizing the second Maestro type (Zimmer Biomet, Warsaw, Indiana) was indicated and opted by the patient. After surgery, a posteroanterior radiograph displayed a correctly aligned implant related to the distal radioulnar joint (Fig. 1D).1Schmidt I. An unusual and complicated course of a giant cell tumor of the capitate bone.Case Rep Orthop. 2016; 20163705808Google Scholar Radiographically, we observed progressive bone resorption that, 6 years after TWA, resulted in the complete yet asymptomatic avascular necrosis of all previously inserted bone grafts encircling the entire capitate peg as well as the asymptomatic sinking of the radial component due to periprosthetic osteolysis (PPO). However, no evident signs of loosening of both components or further changes were observed in the following 2 years (Figure 2, Figure 3A ). The patient remained very satisfied with her midterm to long-term outcomes and conveyed a willingness to undergo wrist prosthesis implantation again at any time if deemed necessary. Pain was assessed as 0 at rest and 2 under load using the visual analog score (scale 0–10). Patient-rated wrist evaluation (0–100 points) was 24, and grip strength (Jamar dynamometer, PhysioSupplies) was 87% of the unaffected left wrist. We observed excellent functional outcomes with an extension-flexion arc of 85° (85% to the left), an ulnar-radial deviation arc of 45° (90% to the left), and a supination-pronation arc of 180° (100% to the left) (Fig. 3B). A revision was not required.Figure 3A A posteroanterior radiograph displaying the complete avascular bone necrosis encircling the entire capitate peg (circle). The radial component has sunk asymptomatically as well (red line against the light-blue line), and multiple radiolucencies and PPO are noted around the entire radial component (arrows). B Clinical photographs demonstrating the excellent functional outcome.View Large Image Figure ViewerDownload Hi-res image Download (PPT) Giant cell tumor of the capitate is rare, with only a few case reports in the literature.1Schmidt I. An unusual and complicated course of a giant cell tumor of the capitate bone.Case Rep Orthop. 2016; 20163705808Google Scholar When treated using curettage (alone or with adjuvant procedures), recurrence is observed in four out of five cases; therefore, primary en bloc resection combined with the third carpometacarpal joint and intercarpal fusions using corticocancellous iliac crest bone grafts is primarily recommended. In these cases, the primary bone healing is usually achieved within 2 months radiographically (macroscopically), which could be confirmed in our case after both procedures.2Oufkir A.A. Lazerges C. Coulet B. Chammas M. Giant cell tumor of the capitate treated with excision and midcarpal fusion.J Wrist Surg. 2017; 6: 238-243Google Scholar Although no recurrence was observed, pronounced OA occurred in the adjacent lunocapitate joint. The occurrence of postoperative OA in the adjacent joints is observed in 23.6% of cases following intralesional curettage combined with all other adjuvant procedures for benign and intermediate bone tumors; notably, a substantial 30.6% of these cases exhibit this occurrence after curettage plus burring alone.3Smolle M.A. Roessl V. Leithner A. Effect of local adjuvants following curettage of benign and intermediate tumours of bone: a systematic review of the literature.Cancers (Basel). 2023; 15: 4258Google Scholar However, the underlying reasons for this phenomenon remain unclear. Mechanical or heat-induced damage to the subchondral capillary network must also be considered. Notably, scaphocapitate and lunocapitate OA are regularly detected in cases of idiopathic avascular necrosis of the capitate.4Athlani L. Granero J. Dap F. Dautel G. Avascular necrosis of the capitate: case series of five patients and review of literature.J Hand Surg Eur Vol. 2019; 44: 702-707Google Scholar The almost isolated OA of the lunocapitate joint in our patient is most likely not be attributed to a scaphoid nonunion etiology. Stress fractures of the scaphoid caused by repetitive microtrauma are uncommon, and only a few case reports exist in the literature.5Kohring J.M. Curtiss H.M. Tyser A.R. A scaphoid stress fracture in a female collegiate-level shot-putter and review of the literature.Case Rep Orthop. 2016; 20168098657Google Scholar Patients often report only nonspecific wrist pain, and correct diagnosis is often delayed. Therefore, assessing with reasonable certainty whether the increasing pain 1 year after the first procedure in our patient was caused by the concomitant scaphoid stress fracture dating back some time, the lunocapitate joint OA alone, or a combination of both was not possible. This is primarily observed in patients with repetitively loaded wrist extensions. Majima et al6Majima M. Horii E. Matsuki H. Hirata H. Genda E. Load transmission through the wrist in the extended position.J Hand Surg Am. 2008; 33: 182-188Google Scholar discovered that during wrist extension, the force transmission shifts radially and concentrates at the waist, which is considered to be the weakest point of the scaphoid. Total wrist arthroplasty is a motion-preserving alternative to total wrist fusion (TWF) in patients with pancarpal wrist OA. The first Maestro type, which uses nonlocking screws for fixation of the carpal component (Fig. 4A), was developed in 2002 by Strickland, Palmer, and Graham and was first available in Europe in 2005. This was followed by the second type, which currently uses existing locking screws (Fig. 4B). However, despite the superiority of Maestro both in terms of survivorship and functional outcome over all other third-generation TWA types (or fourth-generation types when declaring the silicone implants as first type), this implant was withdrawn from the marketplace in 2018, suggesting that the implant was no longer profitable for the company.7Schmidt I. Total wrist replacement: state of the art, challenges and pitfalls: a comparative review.Arch Clin Trials. 2022; 2: 1-18Google Scholar Autologous free nonvascularized iliac crest bone grafting is a well-established procedure; however, its osteoconductive capacity is limited. Healing of autologous bone grafts after curettage of benign tumors in the long bones of the upper and lower extremities with tumor lengths less than 6.2 cm (comparable with our case) is achieved in 79.5% of cases radiographically.8Wu P.K. Chen C.F. Chen C.M. et al.Grafting for bone defects after curettage of benign bone tumor – analysis of factors influencing the bone healing.J Chin Med Assoc. 2018; 81: 643-648Google Scholar However, does microscopic examination also confirm this successful healing in this limited number of cases? Two other factors could also have additional reinforcing impacts on these suggested preexisting molecular disturbances: (1) further mechanical deterioration due to perifocal destruction of the intraosseous capillary network while reaming the canal for press-fit insertion of the capitate peg, and (2) occurrence of unavoidable PPO after TWA. Periprosthetic osteolysis remains unpredictable and is considered a nonseptic inflammation resulting from an interaction between polyethylene (PE) and/or metal wear particles and the immune defense system (macrophages, T cells, and the complementary system). This immune cascade is mainly initiated by mechanical factors, such as micromotions at the implant-bone interfaces or between the implant components. Micromotions may arise from the preexisting mechanical imbalance of implants and iatrogenic-related issues, such as incorrectly aligned implants or ligamentous instabilities (Fig. 5B). Preexisting mechanical disbalance is crucial to all TWA designs primarily because they simplify the "two-type" cardan joint of a normal wrist to a "neo-one-type" radiocarpal joint alone. The fate of the PPO depends on the number of wear particles, and it can dwell in a steady state between bone resorption and formation (eg, stress shielding) or progress toward a loosening of the implant. Periprosthetic osteolysis after TWA mainly occurs juxta-articularly within 6 months after surgery and, analogous to an ulnar head replacement, usually stabilizes within the following 3 years (Fig. 5A). Considering all third-generation TWA types, revision becomes necessary in no more than 20% of cases with second Maestro type, demonstrating superiority at the 10-year follow-up (survivorship with revision in 93% and nonrevision in 90% for implants with radiographic signs of PPO).7Schmidt I. Total wrist replacement: state of the art, challenges and pitfalls: a comparative review.Arch Clin Trials. 2022; 2: 1-18Google Scholar,9Fisher P. Sagerfors M. Jakobsson H. Pettersson K. Total wrist arthroplasty: a 10-year follow-up.J Hand Surg Am. 2020; 45: 780.e1-780.e10Google Scholar Revision is only required if the PPO becomes symptomatic in combination with evident radiographic signs of loosening, such as dislocation or sinking of the carpal or radial components, with or without screw migration or breakage (Figs. 4A, 5B). The fact that the carpal component did not loosen in our patient can be attributed to the effectiveness of the two supporting locking screws. Therefore, care must be taken when using a wrist implant with no (WristArt, Fibioseq) or only nonlocking screws (ReMotion, Stryker) in cases where the capitate is replaced by autologous bone grafts. Nevertheless, the potential for the carpal component to loosen in the future remains, and in this case, two surgical options exist: (1) revision TWA and (2) conversion to TWF. For revision TWA, the use of carpal components with a peg that must be placed press-fit diaphyseally into the third metacarpal is required. Dellacqua10Dellacqua D. Total wrist arthroplasty.Tech Orthop. 2009; 24: 49-57Google Scholar documented a procedure with Maestro involving an extended custom-made peg. Unfortunately, this approach is no longer viable due to the withdrawal of Maestro from the marketplace. Thus, exchange with the Motec wrist implant (Swemac) is currently considered the only method of choice. However, the outcomes of revision TWA are generally worse than those of primary TWA, whereas second-line TWF after failed TWA (Fig. 4A) reveals outcomes comparable to those after first-line TWF.7Schmidt I. Total wrist replacement: state of the art, challenges and pitfalls: a comparative review.Arch Clin Trials. 2022; 2: 1-18Google Scholar We thank the patient for the consent to present her radiographic and clinical findings.