Hand and wrist injuries may have a substantial effect on functional ability, and mangled extremities in particular may lead to permanent disability or even amputation ^[1]. Limb salvage can be difficult in its own right due to its association with high levels of infection, wound issues, and other post-operative complications ^[2]. While the induced membrane (Masquelet) technique is an established treatment option for limb salvage in mangled upper extremities ^[3], this case report highlights the unique use of a ring frame with Masquelet bone grafting for wrist arthrodesis as a limb salvage technique. The case also demonstrates the challenges presented by both the severity of injury in mangled extremities as well as the laborious and intensive treatment process in limb salvage of the mangled upper extremity.

A 37-year-old male presented to our facility after his left arm was caught underneath an ATV rollover. He presented with a grossly contaminated, mangled, and deformed left wrist (Fig. 1). Computed tomography angiography of the extremity demonstrated absent flow in the radial artery but a patent ulnar artery. Radiographs demonstrated distal fractures of both the radius and ulna (Fig. 2) with massive bone loss. On examination, he had absent sensation in the median nerve distribution but intact ulnar sensation. He was able to weakly move all his fingers with the exception of the middle finger distal interphalangeal joint. He was taken immediately to the operating room (OR) for irrigation and debridement (I&D) and wound exploration. On exploration, the radial artery was found to be lacerated and was thus ligated. The median nerve was explored and found to be intact. The extensor indicis proprius was found to be lacerated and partial tearing of the flexor digitorum profundus tendon to the 3^rd digit was discovered. The wound was irrigated and debrided, and segments of nonviable bone involving both the radius and ulna were removed. He was placed into an external fixator with wet to dry dressings placed over the large soft tissue defect (Fig. 3). Empirical antibiotics were started for a severely contaminated wound under the guidance of the Infectious Disease (ID) team.

He was brought back to the OR 2 days later for a repeat I&D. Intraoperatively, there was a hematoma concerning for infection, which after cultured, resulted in Gram-positive bacillus and we subsequently switched to appropriate antibiotic coverage. He was brought to the OR again after 3 days for another repeat I&D, placement of antibiotic beads, and his subcutaneous layer was closed leaving an exposed soft-tissue defect with dressings placed. OR cultures during the debridement showed Aeromonas species and ID was consulted. He was discharged on 6 weeks of IV antibiotics with cefepime and doxycycline. One month later, we brought the patient back to the OR for repeat I&D, but this time with dorsal spanning plate fixation from the 3^rd metacarpal to the remaining radius and a cement spacer to begin the process of the induced membrane (Fig. 4). One month later, he returned to the OR with the plastic surgery team for a free anterolateral thigh myocutaneous flap over his soft tissue defect. After discussion with ID, we opted to keep the patient on antibiotics until his second stage of the Masquelet procedure scheduled to be 2 weeks after the free flap. The flap procedure was successful and after a couple weeks, he underwent his second step of the Masquelet procedure with a fibular strut allograft and iliac crest bone autografting (Fig. 5). The induced membrane was repaired and the plastic surgeon closed the flap that had been elevated for exposure. The patients’ cultures had remained negative to this point and at this point he was transitioned to oral antibiotics (Bactrim and Cefepime).

Six weeks after the second stage of his Masquelet procedure, the patient developed a draining sinus tract on the edge of his free flap. He was taken back by the plastic surgery team for I&D and started back on intravenous antibiotics for 6 weeks. Cultures at that time were negative, although the tract was found to trace back to the hardware. He underwent another repeat debridement with the plastic surgery team 1 month later for persistent erythema and serous drainage around the flap. At this operation, fungal stains taken intraoperatively showed hyphal/yeast elements; however, cultures remained negative throughout the rest of his clinical course. However, given the fungal elements seen on intraoperative specimens, the decision was made to start anti-fungal coverage with Posaconazole. Before this, anti-fungal therapy had not been considered because no fungal elements were seen on intraoperative specimens taken during previous debridements. Three months out from his bone graft procedure, the spanning plate was removed and he was placed into a pin to bar external fixator. There appeared to be healing of the arthrodesis on radiographs; thus, the external fixator was removed. Follow-up radiographs 1 month after fixator removal demonstrated increased volar (apex dorsal) angulation of approximately 15° through the distal forearm (Fig. 6). At this point, the decision was made to place the patient into a ring fixator to improve alignment and allow longer term application of external fixation, and continued observance of the flap (Fig 7 and 8). After 4 months in the ring frame and satisfactory realignment, we removed the frame and placed the patient into a removable short-arm cast. Follow-up radiographs have demonstrated continued bone healing of his wrist fusion (Fig. 9). At most recent follow-up, he is nearly 2 years from his injury and has been able to return to office work (Video 1): Video depicting patient’s intrinsic ability and clinical function.

7122 Video

He has minimal coronal plane angulation and approximately 15° of apex dorsal angulation at the proximal site of his arthrodesis. His DASH score postoperatively was a 6.89 and PRWE score was ^[7].

Hand and wrist injuries may have a substantial effect on functional ability, and mangled extremities in particular may lead to permanent disability or even amputation ^[1]. Limb salvage can be difficult in its own right due to its association with high levels of infection, wound issues, and other post-operative complications ^[2]. While the induced membrane (Masquelet) technique is an established treatment option for limb salvage in mangled upper extremities ^[3], this case report highlights the unique use of a ring frame with Masquelet bone grafting for wrist arthrodesis as a limb salvage technique. The case also demonstrates the challenges presented by both the severity of injury in mangled extremities as well as the laborious and intensive treatment process in limb salvage of the mangled upper extremity. Mangled extremities are often associated with high mechanism of injury and present a unique challenge to the treating surgeon ^[4]. The limb is considered mangled if three or more of four tissue components are affected (bone, soft tissue, nerves, and vessels). In addition to proper resuscitation, Miller et al. summarize the appropriate steps in management of the mangled upper extremity beginning with infection prevention with debridement and timely antibiotics within 24 h ^[5]. Afterward, a decision must be made to either amputate or attempt limb salvage. Limb salvage can be a difficult and challenging form of management due to the high rates of infection, initial soft-tissue insult, wound issues, as well as the inherent difficulties that come with restoring function after significant disruption to the native anatomy of the upper extremity. Once the decision to proceed with limb salvage is made, skeletal stabilization is performed followed by addressing soft-tissue coverage ^[6]. The mangled extremity severity grading system was described in 1985 by Gregory et al. which classified injuries based on the damage to four major tissue systems: Integument, nerve, artery, and bone ^[3]. They concluded that patients who ultimately underwent amputation could have been identified at initial evaluation using this system. Similarly, Johansen et al. describe the Mangled Extremity Severity Score (MESS) for lower extremity injuries based on skeletal/soft-tissue damage, limb ischemia, shock, and age and concluded from their study that a score greater than or equal to 7 predicted amputations with 100% accuracy ^[7]. Since then, several reports have highlighted the challenges and shortfalls of applying a score developed for lower extremity injuries to the upper extremity [5,6,8-10]. Furthermore, given the advancement of multidisciplinary treatment of mangled extremities and medical innovation in recent years, the predictive accuracy of the MESS in regard to need for amputation has decreased ^[8]. Segmental bone loss can be managed with a variety of techniques including vascularized and non-vascularized autogenous bone grafts ^[11], allografts ^[12], Ilizarov bone transport ^[13], acute shortening ^[14], and amputation. The induced membrane technique first described by Masquelet et al. ^[15] describes a two-stage technique used as first-line treatment for segmental bone defects or when other reconstruction techniques such as vascularized bone transfer or the Ilizarov technique fail. The first stage is using a cement spacer to temporarily fill a bone defect or void. The second stage is reconstruction using autologous cancellous bone graft. The “induced membrane” formed around the cement spacer prevents resorption of the graft and encourages vascularization and corticalization [15, 16]. Although the exact biological mechanism of the technique is unknown, the Masquelet technique now has a wide variety of applications in bone reconstruction and has gained significant traction in recent years due to its reproducibility, less dependence on patient compliance (compared to bone transport), and is in “theory” length independent [17,]. The induced membrane involves multiple cellular processes, including mesenchymal stem cells and miRNA to create an enclosed setting that may release growth factors as well as impede the infiltration of fibroblasts, adipose tissue, and the absorption of bone graft [18, 19]. This creates a favorable environment for angiogenesis, differentiation of mesenchymal stem cells into osteogenic pathways and forming new bone [18, 19]. However, changes in gene expression and the exact mechanism behind the bone healing process using the Masquelet technique are still unclear. In the lower extremity, Azi et al. demonstrated segmental bone defects in average of 6.7 cm in the femur and tibia treated with induced membrane technique to have achieved bone union in 90% of cases in an average of 8.5 months ^[20]. The Masquelet technique was initially described in the treatment of long bones of the lower extremity; however, several cases have reported its application and success in the upper extremity [21-23]. In our case, the induced membrane technique was used to address the significant bone loss of the distal radius but more uniquely, was used for fusion of the wrist joint, which to our knowledge is a novel application of the Masquelet technique. Pederiva et al. performed a systematic review of the Masquelet technique applied in upper extremities and reviewed 15 studies with a total of 156 patients. The average size of the defect was 2.5 cm at the humeral level and 5 cm at the forearm level with a complication rate of 21% with infection requiring debridement being the most common ^[24]. This article aligns with the findings of our case report and highlights the effectiveness of the Masquelet and its use in the upper extremity despite complication rates being high. The practicing surgeon should be able to appropriately handle and address complications as they arise to provide the patient with the best outcome possible. Our patient developed draining sinus tracts and increased angulation necessitating a ring frame for final fusion; however, he ultimately was able to retain significant functionality of his affected extremity with the ability to return to work and perform activities of daily living with a DASH score of 6.89 and a PRWE score of 7.

We present a unique case report of a 37-year-old male who presented with a mangled left wrist with significant segmental bone loss of the distal radius treated successfully with induced membrane technique and wrist arthrodesis. This case report highlights the ability to achieve wrist fusion through the induced membrane technique and the use of a ring external fixator in the treatment of a mangled upper extremity.

In the mangled extremity with segmental bone loss, the limb salvage technique through wrist fusion using the induced membrane technique is a viable treatment option and should be attempted before resorting to amputation.