Ultrasound Evaluation of Radial Nerve Palsy Associated with Humeral Shaft Fractures to Guide Operative Versus Non-Operative Treatment.

OBJECTIVE: To determine the effectiveness of diagnostic ultrasound (US) at evaluating the condition of the radial nerve in the setting of humeral shaft fractures. MATERIALS AND METHODS: An observational study was performed of 18 patients with radial nerve palsy associated with humeral shaft fractures who underwent US examination to assess the condition of the radial nerve. RESULTS: Six patients with humeral shaft fractures treated nonoperatively in a functional brace had US findings consistent with contusion or stretch radial nerve injury. Twelve patients ultimately underwent surgery either because US showed an entrapped or lacerated radial nerve, or for other operative indications. There was a 92% concordance (11/12 patients) between US and intraoperative findings with regards to the condition and location of the radial nerve, with the remaining case being complicated by delayed surgical treatment secondary to patient factors. CONCLUSION: Our study demonstrates that US is an effective diagnostic tool in evaluating radial nerve injuries in the setting of humeral shaft fractures and can aid in clinical decision making by differentiating between patients with nerve laceration or entrapment who may benefit from surgery from those with neurapraxia managed nonoperatively.

Lower Leg Fracture Irreducibility Resulting From Entrapment of the Fibula Within the Tibial Shaft.

The tibia is the most commonly fractured long bone. Tibia fractures are simple, and most are amenable to immediate closed reduction. Reported cases of irreducibility resulting from entrapment of soft-tissue structures are rare. We report the case of a 23-year-old man who, in a high-speed motor vehicle crash, sustained a closed lower leg fracture that was later found to have a unique pattern in which the fibula was entrapped in the medullary cavity of the tibia. Limited open reduction was performed, and the entrapped distal fibula was removed with use of a bone hook. The tibia was reduced, and a nail placed in standard fashion. The postoperative course leading to full recovery was unremarkable. This irreducible fracture pattern, not previously reported, should be considered during difficult closed reductions in order to prevent unnecessary neurovascular or bony injury.

Brachial Plexopathy Following Use of Recombinant Human BMP-2 for Treatment of Atrophic Delayed Union of the Clavicle.

CASE: Although recombinant human bone morphogenetic protein-2 (rhBMP-2) is approved for treatment of open tibial fractures and anterior lumbar interbody fusion, off-label use has been associated with complications such as local inflammation, osteolysis, and dysphagia. This case report describes a patient treated with rhBMP-2 for an atrophic delayed union of a clavicular fracture who subsequently developed a profound motor and sensory brachial plexopathy. CONCLUSION: Use of rhBMP-2 near peripheral nerves may cause neuropathy. This should be considered prior to its use in surgical sites with peripheral nerves in proximity.

Axonal loss in murine peripheral nerves following exposure to recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge.

BACKGROUND: With the proven efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2) to treat open tibial fractures and promote spine fusion, there has been an increase in its off-label use. Recent studies have shown that BMPs play a role in nerve development and regeneration. Little is known about changes that result when rhBMP-2 is used in the vicinity of peripheral nerves. The purpose of this study is to characterize changes in peripheral nerves following exposure to rhBMP-2-soaked collagen sponges. METHODS: rhBMP-2 on an absorbable collagen sponge (ACS) was implanted directly on the sciatic nerves of Wistar rats. One and three weeks following surgery, the nerves were harvested and histological analysis was performed to evaluate inflammatory and structural changes. RESULTS: rhBMP-2-soaked collagen sponges induced ectopic bone formation in muscle tissue in all animals after three weeks, but did not cause bone formation within the nerve. Axonal swelling and splitting of the myelin sheath were observed in both experimental and control nerves and may be a result of surgical manipulation. The overall incidence of axonal loss was 15.8% in the rhBMP-2/ACS-exposed nerves and was 0% in control nerves (p < 0.05). CONCLUSIONS: rhBMP-2-soaked collagen sponges may adversely affect the axons of peripheral nerves by causing axonal dropout and loss of axons. Ectopic bone formation occurs within muscle tissues and not within the peripheral nerve. The axonal dropout may be a direct effect of rhBMP-2-soaked collagen sponges and not nerve compression as it was observed prior to ectopic bone formation.

Biomechanical evaluation of suture-augmented locking plate fixation for proximal third fractures of the olecranon.

OBJECTIVES: To describe a method of suture augmentation of locking plate fixation (PF) of proximal olecranon fractures and to evaluate the biomechanical effectiveness of the suture augmentation using a human cadaveric model. METHODS: Six matched pairs of cadaveric elbows were used. Proximal one-third fractures of the olecranon were simulated via a transverse osteotomy. Identical locking PF was performed on each elbow using olecranon locking plates. One elbow of each pair was assigned to suture augmentation of the construct. The choice of left/right specimen for augmentation was performed in an alternating fashion. Augmentation was performed using a no. 2 ultra-high-molecular weight polyethylene-braided suture attaching the triceps to the plate via a modified Krackow stitch. The elbows were mounted into a custom jig and linearly loaded to failure using a hydraulic testing machine. Load to and modes of failure were recorded for each sample. The data were analyzed using the Wilcoxon signed-rank test for nonparametric distributions. RESULTS: Suture augmentation improved the single load-to-failure strength in all pairs. One pair was excluded due to failure of the triceps attachment to the test machine. A median 398 N (P = 0.04 range, 197-633 N) or a median 48% (range, 30%-130%) improvement in strength was seen. The most common mode of failure was loss of fixation of the proximal olecranon fragment. CONCLUSIONS: Suture augmentation can significantly increase the single load-to-failure strength of locking PF for proximal olecranon fractures.