Intraprosthetic Dislocation of a Modular Dual-Mobility Total Hip Arthroplasty With Posterior Migration of the Polyethylene Liner.

Dual-mobility (DM) implants have been used in total hip arthroplasty since 1974. Modular DM implants have seen an increase in use in primary and revision total hip arthroplasties given the theoretical decreased dislocation rate. DM constructs have 2 articulation sites, one between the acetabular shell and a polyethylene liner, as well as one between the liner and the femoral head component. However, dislocations with modular DM implant dislocations can still occur. These dislocations occur via an extraprosthetic or intraprosthetic mechanism. Intraprosthetic dislocation is a phenomenon in which the smaller femoral head dissociates from the polyethylene liner. We present a case of intraprosthetic dislocation in an 81-year-old female with migration of the polyethylene liner into her gluteal muscles after 2 attempted closed reductions.

Spontaneous Unilateral Chiari I Secondary to Acquired Tonsillar Hypertrophy/Pseudomass With Syringomyelia in a Juvenile With Progressive Scoliosis.

Chiari type 1 malformation (CM-1) is a structural defect of the central nervous system in which part of the cerebellar tonsils descend below the level of the foramen magnum, sometimes with associated syringomyelia. Although Chiari malformations were traditionally believed to be congenital, several cases of acquired CM-1 with syringomyelia have been reported. Usually associated with repeat lumbar puncture, increased intracranial pressure, and craniocephalic disproportion, CM-1 in the absence of an underlying etiology is rare. We report a rare case of spontaneous idiopathic tonsillar hypertrophy causing unilateral CM-1 with syringomyelia associated with progressive scoliosis in a juvenile with a previously normal neonatal MRI brain and no known underlying pathology. A 9-year-old boy was found to have scoliosis at a routine well-child visit with progression indicated on radiographs 4 months later. Whole spine MRI was performed and showed a new CM-1 with globular, mass-like configuration of the descended right tonsil with otherwise normal tonsillar characteristics. Surgical decompression via suboccipital craniectomy and C1 laminectomy with duraplasty was performed with improvement illustrated on repeat MRI 3 months postoperatively. This rare case emphasizes the importance of routine MRI spine early in select patients with idiopathic scoliosis and illustrates the favorable outcomes noted after decompressive craniectomy.

Liposomal bupivacaine in posterior spine surgery: A piece of the puzzle for postoperative pain.

Background: Liposomal bupivacaine (LB) is a local analgesic that may be used at the time of surgery to limit postoperative pain around the surgical site. Its efficacy in decreasing pain, decreasing narcotic consumption, decreasing length of stay, and improving mobility is an area of intense research. The purpose of this study was to determine whether LB use was associated with improved patient-reported pain scores in the first 72 h following posterior spinal surgery, decreased postoperative narcotic need, and decreased length of stay. Methods: One hundred and five patients undergoing elective posterior cervical or lumbar surgery were included in retrospective analysis. Forty-eight patients who received LB intraoperatively were compared with a historical cohort of 56 patients who underwent similar procedures and did not receive postsurgical infiltration with local analgesia. The same pain medication protocol was utilized postoperatively. Results: Demographics, clinical characteristics, and total morphine milligram equivalents did not differ significantly between the groups. The treatment group averaged a decreased length of stay (1.85 days treatment, 2.68 days control, p = 0.057). Treatment with LB was associated with lower pain levels at 24 h (5.2 treatment, 6.4 control, p = 0.04) and 48-72 h (4.9 treatment, 6.6 control, p = 0.007) after surgery. Conclusions: LB improved patient perception of pain in the acute postoperative time period.Intraoperative LB injection, coupled with focused early mobilization efforts and multimodal pain control, may lead to improved patient-reported outcomes, shorter length of stay, and decreased risk of perioperative complications.