Figure 1
Total wrist arthroplasty (TWA) has emerged as an increasingly viable alternative to total wrist fusion for patients with severe wrist conditions. However, the long-term efficacy of TWA, particularly with regard to the role of locking screws, has been the subject of ongoing debate. A recent case study by Dr. Ingo Schmidt of Private Orthopaedic Practice in Germany, published in the Journal of Hand Surgery Global Online, sheds new light on this issue through an eight-year follow-up of a patient who underwent TWA with a second-type Maestro wrist prosthesis.
Dr. Schmidt describes the extremely rare case of a middle-aged woman who was diagnosed with a Campanacci grade II giant cell tumor of the capitate bone of her right wrist. She was initially treated with intralesional curettage and bone grafting. However, the patient experienced recurrent wrist pain, leading to a series of interventions, including four-corner fusion and eventual implantation of a second-type Maestro wrist prosthesis. This prosthesis, notable for its use of locking screws, was inserted after two failed motion-preserving procedures (Figure 1).
During the eight-year follow-up, the patient showed complete but asymptomatic avascular necrosis of all previously inserted bone grafts around the capitate, but without any obvious loosening of the carpal component (Figure 2). However, in contrast to these remarkable radiographic findings, the patient reported high levels of satisfaction along with excellent functional results and only minimal pain under weight-bearing conditions (Figure 3). No implant revision was necessary.
The study highlights the crucial role of locking screws in improving the durability and functionality of total wrist arthroplasty. According to Dr. Schmidt, “The use of locking screws significantly improves the longevity of total wrist arthroplasty by mimicking external or internal fixation for large bony defects in long bones.”
Interestingly, the case study revealed that while the patient experienced progressive bone resorption leading to avascular necrosis, this did not translate into clinical symptoms or reduced functionality. The patient maintained excellent wrist function, with significant range of motion and grip strength comparable to the unaffected wrist. This highlights the potential of locking screws to ensure mechanical stability of wrist implants, even in the presence of bone necrosis.
The findings of this case report emphasize the importance of selecting appropriate wrist implants equipped with locking screws for patients undergoing TWA. Dr. Schmidt suggests that the two supporting locking screws minimized unfavorable shear forces at the implant-screw-bone interface, thereby preventing loosening. This stability is crucial, especially in cases where the capitate bone is replaced by bone grafts, as nonlocking screws may not provide sufficient long-term fixation.
The Maestro prosthesis was the world’s first wrist implant that allowed fixation of the carpal component with locking screws. However, despite the Maestro’s superiority both in terms of survival and functional outcome over all other third-generation TWA types (or fourth-generation if silicone implants are declared as the first type), this implant was incomprehensibly withdrawn from the market in 2018, suggesting that the implant was no longer profitable for the company.
The long-term success of TWA with locking screws, as demonstrated in this case, challenges previous concerns about the durability of wrist implants. It suggests that correct use of locking screws can significantly extend the life of TWA, reducing the need for revision surgeries. However, Dr. Schmidt cautions that while current results are promising, there remains the potential for loosening in the future, necessitating ongoing monitoring.
Dr. Schmidt’s study provides valuable insight into the long-term management of traumatic wrist arthroplasty, particularly with regard to implant choice and fixation methods. It highlights the need to consider the use of locking screws in traumatic wrist arthroplasty procedures to improve implant stability and patient outcomes. As wrist arthroplasty continues to evolve, these findings will inform future surgical practices and implant designs, ensuring better care for patients with severe wrist conditions.
Journal reference
Schmidt, Ingo. “The crucial role of locking screws in total wrist arthroplasty: should we always check or not?” Journal of Hand Surgery Global Online, 2024. DOI: https://doi.org/10.1016/j.jhsg.2024.01.002
About the Author
Dr. Ingo Schmidt Dr. Schmidt qualified as a general surgeon, traumatologist, orthopedic surgeon, hand surgeon and plastic surgeon at the Friedrich-Schiller University Hospital in Jena (Germany) between 1990 and 1999. During this time, he developed and patented a novel dynamic external mini-fixator for the hand with options for ligamentotaxis in cases of severely comminuted intra-articular fractures, bone lengthening (callotaxis) and passive external stretching for soft tissue contractures such as Dupuytren’s disease (PMID 8585344_1995 and 33173674_2020). He received his medical degree in 1994 for his electromyographic studies after proximal biceps tendon ruptures (PMID 7502385_1995). Dr. Schmidt then specialized in particular in the field of joint replacements for the entire hand. He is an internationally recognized specialist in total wrist arthroplasty with numerous publications and valuable presentations at conferences and symposia, and works as a reviewer for several prestigious scientific journals.
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