Effective shape of ball-and-socket prosthesis in restoring range of thumb motion for total thumb carpometacarpal joint arthroplasty: three-dimensional motion analysis.

PURPOSE: Total joint arthroplasty (TJA) has often been used to treat thumb carpometacarpal (CMC) osteoarthritis (OA). However, guidelines for the CMC prosthesis shape remain unclear. This study aimed to identify the effective shape of a ball-and-socket prosthesis in restoring the range of thumb motion after TJA. METHODS: The participants were 10 healthy young adult men (22-32 years; 26.8 ± 3.57 [mean ± SD]). CT scans were performed in eight static limb positions during abduction and flexion. We defined three design variables (offset R, height H, and neck rotation angle Φ) as the variables that determine the basic shape of the ball-and-socket prosthesis. The ideal values of these design variables were examined based on the results of a 3D motion analysis, which evaluated the change in the posture of the first metacarpal (r, h, and φ corresponding to R, H, and Φ, respectively) relative to the center of rotation (COR) during abduction and flexion. We also simulated the effect of these design variables on the range of thumb motion after TJA using 3D CAD. RESULTS: We found that the values of r and h averaged over all limb positions were 6.92 ± 1.60 mm and 51.02 ± 1.67 mm, respectively, showing that these values remained constant regardless of limb position. In contrast, φ changed significantly. The simulation results indicated that Φ affected the range of thumb motion after TJA, and Φ = 0° relatively reproduced all limb positions compared to other values. CONCLUSION: Our results suggested that the desirable values of R and H were the average of r and h over several limb positions and that Φ = 0° was effective in restoring the range of thumb motion after TJA. Our results will provide surgeons with new guidelines for selecting a prosthesis.

Enhanced nerve autograft using stromal vascular fraction.

PURPOSE: While many studies have been conducted on peripheral nerve regeneration, few have focused on strengthening the nerve autografts. This study hypothesized that adding autologous stromal vascular fraction (SVF) to a nerve autograft will improve nerve regeneration. The purpose of this study was to compare the results of nerve autograft with and without SVF. METHODS: An adipose tissue sample was excised from the right inguinal region of female Wistar rats, and SVF was separated by centrifugation. The left sciatic nerve was resected at a length of 15 mm and the defect was bridged by a resected nerve autograft. We added SVF with collagen gel around the nerve autograft in the SVF group and added saline in the control group. At 12 weeks after surgery, the wet muscle weight, distal latency, and amplitude of the compound muscle action potential of the tibialis anterior were evaluated by the ratio of left and right sides. Sciatic functional index (SFI) was also evaluated. RESULTS: The wet muscle weight was significantly better in the SVF group than in the control group. The results of distal latency, amplitude, and SFI were not significantly different between the two groups; however, these results tended to be better in the SVF group than in the control group. CONCLUSION: SVF added to artificial nerve grafts has been reported to promote axonal regeneration through secretion of angiogenic, neurotrophic, and anti-apoptotic factors. This study indicates that SVF may also be effective for nerve autografts and improve the clinical result of nerve autograft.

Iatrogenic sciatic nerve injury due to cerclage wiring for proximal periprosthetic femoral fracture: A rare case report.

Cerclage wiring is used to reinforce the stability of fractures and optimize plate fixations for femoral fractures such as periprosthetic fractures. However, cerclage wiring requires attention to neurovascular structures to prevent injuries. We have presented a case of iatrogenic sciatic nerve injury after osteosynthesis with cerclage wiring. A 71-year-old woman underwent osteosynthesis with cerclage wiring for a proximal periprosthetic femoral fracture. Immediately after the operation, the patient developed motor and sensory disorders, particularly in the sciatic nerve area, leading to a suspicion of nerve injury. Consequently, reoperation showed that the right sciatic nerve was strangulated by the cerclage wire, but the nerve was functional. Since the sciatic nerve was partially continuous and retained sensation to some extent, strangulation release was performed. Subsequently, both sensory and motor disorders improved. This case suggests that attention should be given to not only the blood vessels in the anterior region but also the sciatic nerve in the posterior region when performing cerclage wiring for femoral fractures.

In Carpal Tunnel Syndrome, Sensory Nerve Conduction Velocities Are Worst in the Middle Finger Than in the Index Finger.

Although the index finger is generally used for sensory nerve conduction study in cases of carpal tunnel syndrome, there are reports that the middle finger should be used. The purpose of this study was to compare the results of sensory nerve conduction studies of the index finger and middle finger in patients with carpal tunnel syndrome. Among the 120 hands of 93 patients who were diagnosed with carpal tunnel syndrome and underwent carpal tunnel release surgery at our hospital, 54 hands of 48 patients who showed waveforms in sensory nerve conduction studies both index and middle fingers were included. 6 hands of 6 patients who showed no waveform in the index or middle finger, and 60 hands of 39 patients who showed no waveform in both index and middle finger were excluded. The subjects were 14 males and 34 females, and their ages were 66.2 years. The preoperative sensory nerve action potential (µV) and sensory nerve conduction velocity (m/s) of the index and middle fingers were tested using Wilcoxon's signed rank test. Spearman's rank correlation coefficient was also calculated for the results of the index and middle fingers. Sensory nerve action potentials were 2.0 in the index finger and 1.8 in the middle finger, with significantly lower in the middle finger. Sensory nerve conduction velocity was 30.1 in the index finger and 27.2 in the middle finger, with significantly lower in the middle finger. The correlation coefficients of sensory nerve action potentials and conduction velocities between the index finger and middle finger were 0.82 and 0.96, respectively, both of which showed a significant correlation. The results of the sensory nerve conduction studies of the middle finger were significantly worse than those of the index finger in cases of carpal tunnel syndrome. In addition, there was a strong correlation between the results of the index finger and the middle finger. The results of this study suggest that the nerve bundle to the middle finger may be more strongly affected than the nerve bundle to the index finger in cases of carpal tunnel syndrome.

Common peroneal nerve rupture with multiple ligament knee injury: A case report.

In peroneal nerve palsy with closed knee injury, most of the case improves by follow-up. We present a case of peroneal nerve rupture with closed multiple ligament knee injury, requiring nerve transplantation. In multiple ligament knee injury, it is necessary to consider the possibility of peroneal nerve rupture.

Deep inferior epigastric artery as a collateral pathway to the lower extremities: A case report.

We describe a patient in whom the deep inferior epigastric artery served as a collateral pathway to the lower extremities, and free latissimus dorsi myocutaneous flap transfer was successfully used for reconstruction instead of the originally planned free rectus abdominis myocutaneous flap. A 74-year-old woman underwent subtotal tongue resection, followed by free flap tongue reconstruction for tongue cancer. Reconstruction using a free rectus abdominis myocutaneous flap was considered; however, preoperative contrast-enhanced computed tomography revealed complete occlusion of the bilateral external iliac arteries. Doppler ultrasonography revealed retrograde blood flow via the deep inferior epigastric artery, and the internal thoracic artery-deep inferior epigastric artery pathway served as a collateral pathway that supplied the lower extremities. The patient underwent reconstructive surgery using a free latissimus dorsi myocutaneous flap, and the flap completely survived. The internal thoracic artery-deep inferior epigastric artery pathway serves as a critical collateral pathway to the lower extremities in patients with aortoiliac occlusive disease. Blockage of the deep inferior epigastric artery in patients in whom this vessel shows retrograde blood flow may result in lower extremity ischemia. Therefore, preoperative Doppler ultrasonography is warranted to confirm the direction of the blood flow, in addition to evaluation of the deep inferior epigastric artery and its perforators before planning rectus abdominis myocutaneous flap or deep inferior epigastric artery perforator flap surgery.

Profunda femoris artery perforator flap for lateral knee joint reconstruction: A report of two cases.

The profunda femoris artery perforator flap (PAP) based on a proximal skin perforator is often used for breast reconstruction. We report two cases of lateral knee joint reconstruction using a PAP flap based on a distal skin perforator. Case 1 is a 16-year-old male adolescent who underwent inappropriate resection of a synovial sarcoma on the lateral aspect of the right knee joint, which necessitated additional wide resection that led to a soft tissue defect measuring 11 × 5 cm. We elevated a propeller PAP flap (23 × 7 cm) for defect reconstruction, and the flap survived completely. Case 2 is an 81-year-old woman who underwent wide resection of an undifferentiated pleomorphic sarcoma on the lateral aspect of the right knee joint showed a persistent soft tissue defect measuring 9 × 6 cm. We elevated a propeller PAP flap (25 × 7 cm) as described in Case 1, and the flap survived completely. Skin perforators of the profunda femoris artery are present both in the proximal and distal thigh; therefore, a PAP flap can also be elevated in the distal thigh. However, a few reports have discussed PAP flap elevation in the distal thigh for knee joint reconstruction. The PAP flap with a distal skin perforator can be elevated with a relatively large volume of skin paddle and may be a useful option for lateral knee joint reconstruction.

Optimal Center of Rotation for Ball-And-Socket Thumb Carpometacarpal Arthroplasty Identified Using Three-Dimensional Kinematic Analysis: A Pilot Study.

Total joint arthroplasty is one of the surgical option for thumb carpometacarpal (CMC) joint arthritis, however the optimal position the center of rotation (COR) has not been quantified. The purpose of this study is to identify ideal ball-and-socket thumb carpometacarpal joint implants and the optimal position of the COR. We obtained eight right thumb computed tomography images each from ten healthy men, comprising four images each of thumbs at various angles of flexion-extension and abduction-adduction. We reconstructed 3D bone models on 3D CAD, created virtual ball-and-socket implants with three variables (neck offset, implant height, neck rotation), and found the optimal COR where the position change in the COR was smallest across various thumb positions. When the offset was 4.5 mm, neck rotation angle was 130.6° from the radial side to the palmar side of the first metacarpal, and implant height from the distal end of the metacarpal was 43.6 mm, we could restore almost normal kinematics. This study could serve as a reference for implant development and surgical technique guidelines.

Anaphylactic Reactions Caused by Nafamostat Mesylate during Hemodialysis before Surgery for Carpal Tunnel Syndrome.

Nafamostat mesylate (NM) has been used to treat pancreatitis and disseminated intravascular coagulation during hemodialysis (HD). However, there have been some reports of adverse effects related to anaphylactic reactions. We present a case in which anaphylactic reactions caused by NM during preoperative HD caused repeated postponement of surgery for carpal tunnel syndrome. Symptoms including fever, shivering, chills, low blood pressure, tachycardia, nausea, and vomiting appeared during preoperative HD, and surgery was postponed thrice. Initially, the patient was misdiagnosed with sepsis because of elevated C-reactive protein and procalcitonin levels. However, since the symptoms appeared only when NM was administered and disappeared quickly after the administration of NM was terminated, the condition was diagnosed as anaphylactic reactions caused by NM. Therefore, it is essential to consider anaphylactic reactions caused by NM as differential diagnoses, when symptoms, such as fever, are observed during perioperative HD.

Case Report: Prophylactic Plate Fixation for Incomplete Atypical Ulnar Fractures Resulting From the Use of Denosumab for Bone Metastases.

Patients with bone metastases are treated with long-term bone resorption inhibitors such as bisphosphonates and denosumab. However, resorption inhibitors have been known to cause fractures, such as atypical femoral fractures (AFFs). In recent years, there have been an increasing number of reports of atypical ulna fractures (AUFs) caused by bone resorption inhibitor usage. Treatment of AUFs is complicated, especially when they occur in patients with bone metastases, because it is difficult to discontinue bone resorption inhibitor treatment without the risk of aggravating metastatic lesions. Prophylactic surgery is recommended in AFFs when fractures are predicted, but there are few reports of prophylactic surgery for AUFs. Here, we report a case of incomplete AUF in a 74-year-old woman which was surgically treated with prophylactic plate fixation. The patient had been using denosumab for 6 years to treat bone metastases due to thyroid cancer. After surgery, no fractures were observed for 2 years without discontinuing denosumab, and her forearm function was adequate. AUFs are rare and difficult to treat, so oncologists who treat bone metastases need to pay special attention to diagnose this incomplete AUF before the fracture worsens. We believe that detection of a possible fracture and prophylactic surgery can improve prognosis.

In Vivo Kinematics of the Thumb Carpometacarpal Joint During Flexion and Abduction.

Background: Despite the movement of the thumb carpometacarpal joint has been studied, many unclarified points remain regarding the movement of this joint. The purpose of this study was to evaluate the in vivo kinematics of the thumb carpometacarpal joint during flexion and abduction using computed tomography images. Methods: The subjects were 9 healthy males. Computed tomography images were obtained in 4 equally-divided positions from maximum extension to maximum flexion, and maximum adduction to maximum abduction of the thumb. A three-dimensional model was constructed from these images, and the models of each position were superimposed with reference to the trapezium. The amount of angular change around the bone axes of first metacarpal bone and rotation axes were evaluated. Results: We found that the first metacarpal bone showed relatively simple behavior during abduction. However, during flexion, it exhibited a particular movement in which the amount of angular change of the metacarpal bone with respect to the trapezium rapidly increased with deep flexion. Conclusions: These results suggest that the thumb carpometacarpal joint exhibits a special movement during flexion, especially deep flexion.

Sensory Disturbance of the Lower Extremity after Sural Artery Flap Elevation.

PURPOSE: Elevation of the sural artery flap with the sural nerve is associated with donor-site morbidities, such as postoperative sensory disturbance of the lower extremity. We evaluated the sensory disturbance of the lower extremity after elevation of the sural artery flap. METHODS: This study included 7 patients who underwent surgery using the sural artery flap. The sensory disturbances immediately after surgery and at present were evaluated on a 10-point scale. The influences of surgery on activities of daily living and patient satisfaction were also evaluated. RESULTS: The sensory disturbance was 4.48 immediately after surgery and 2.24 presently, and the difference between the timepoints was not statistically significant. The influence of surgery on activities of daily living was 2.30, and the patient satisfaction was 7.90. CONCLUSION: It may be necessary to consider the sural artery flap, which does not include the sural nerve, to avoid unnecessary complications. When it is unavoidable to use the sural artery flap, including the sural nerve, it is important to thoroughly inform patients beforehand about the postsurgery sensory disturbance in the lower extremities.

Screw fixation without bone grafting for scaphoid fracture nonunion.

INTRODUCTION: We previously reported the classification of the scaphoid fracture nonunions as linear, cystic, and sclerotic or displaced types based on radiographic findings. We have been treating the linear and cystic type fractures via screw fixation without bone grafting and the sclerotic or displaced type fractures via screw fixation with bone grafting. In this retrospective study, we report the treatment outcomes of the linear and cystic types of scaphoid fracture nonunions. METHODS: Nineteen patients with linear and cystic type scaphoid fracture nonunions were included. Two patients had linear type and 17 had cystic type fractures. All the patients were male, their mean age was 29.2 years. All patients were treated with screw fixation alone by a single surgeon. RESULTS: Bone union was achieved in 17 cases. The mean time to bone union was 3.7 months. Bone union was not achieved in one case of linear type and one case of cystic type fracture. The former was thought to be due to misdiagnosis of displaced type as linear type fracture; however, no obvious reason could be found for the latter. DISCUSSION: Screw fixation alone could help achieve bone union in linear type scaphoid fracture nonunions. However, if the type of the fracture is difficult to diagnose based on plain radiography, evaluation using computed tomography should be performed. The cystic type fractures may need to be subclassified according to the location or size of the cyst as well as the viability of the proximal bone fragment.

Use of a Free Vascularized Medial Femoral Condyle Flap for Revision Surgery in a Pediatric Patient with Congenital Pseudarthrosis of the Clavicle.

The most common surgical treatment for congenital pseudarthrosis of the clavicle (CPC) is resection of the pseudarthrosis, placement of an autologous bone graft, and Kirschner wire or plate fixation. However, in some cases, bone fusion cannot be achieved at the first surgery, and an additional surgery is required. We present a case report of a boy with a right CPC who failed radiographic bone union after the first surgery. He subsequently underwent revision surgery with resection of the pseudarthrosis, plate fixation, and establishment of a vascularized medial femoral condyle (MFC) flap to ensure bone union. Three months after the revision surgery, a radiographic bone union was achieved, and no symptoms were observed for one year after the operation. There have been no previous reports of the use of a vascularized MFC flap as a treatment for CPC. We believe that this technique effectively ensures bone union during revision surgery for CPC.

Effects of hybridization of decellularized allogenic nerves with adipose-derive stem cell sheets to facilitate nerve regeneration.

We developed a sheet of stem cells derived from adipose tissue (ADSC sheet). To improve transplantation, we wrapped decellularized nerves with ADSC sheets and examined the efficacy of this recellularized nerves in nerve regeneration. Decellularized nerves were prepared from sciatic nerves of Sprague-Dawley rats. Wistar rats were subjected to sciatic nerve injury and then randomly assigned to three groups (n = 7 per group), which were transplanted with 15-mm bridge grafts; the first group received a decellularized allogenic nerve implant, the second an ADSC sheet-wrapped decellularized allogenic nerve implant, and the third an autogenous nerves were implant. No significant differences were found in S100-positive and neurofilament-positive areas, axon density, and sciatic functional index (SFI) score between rats transplanted with ADSC sheet-wrapped nerve grafts and those that received autografts. In contrast, these parameters except SFI and the amplitude ratio were significantly larger in rats grafted with ADSC sheet-wrapped nerve than with the decellularized nerve. These results suggest that the number of regenerating axons, as well as their regenerating velocity, and the number of migrating Schwann cells into the implant in rats transplanted with ADSC sheet-wrapped nerves matched those in rats transplanted with autografts. These positive effects are possibly attributable to secretion of growth factors of ADSCs.