The pericapsular nerve group block: a step towards outpatient total hip arthroplasty?

INTRODUCTION: A new regional anaesthetic technique, coined the pericapsular nerve group (PENG) block, targets the anterior hip capsule by blocking the articular branches of the femoral nerve and accessory obturator nerve. In this study, we evaluated: (1) patient outcomes; (2) postoperative pain scores; and (3) postoperative opioid consumption in total hip arthroplasty (THA) patients who received a PENG block in comparison to a control group. METHODS: A retrospective chart review was performed for patients who underwent primary THA and met criteria at a single institution (n = 48), with an additional cohort of patients collected as controls (n = 48). Postoperative pain scores were measured by obtaining the cumulative visual analogue scores (VAS) at 12-hour intervals until the 48-hour benchmark. All administered opioids were collected from postoperative day (POD) 0 to POD2 and converted to morphine milligram equivalents (MME). RESULTS: In the PENG group, length of stay was significantly shorter (p < 0.001) and the initial postoperative distance walked was significantly farther (p = 0.001). The PENG group consistently demonstrated significantly lower mean cumulative pain scores until the 48-hour mark (p < 0.001 for all). Patients receiving the PENG block also experienced a significantly longer therapeutic window before requiring their first opioid (p < 0.002). The PENG group required significantly less opioid MMEs on POD1, POD2, and cumulatively over the entire stay (p < 0.022 for all). CONCLUSIONS: Our findings suggest that the PENG block has the potential of impacting THA recovery pathways and contributing to cost savings. Thus, its use further supports the transition to the outpatient setting and drives us towards achieving value-driven healthcare.

Two-Stage Exchange Using a Short Intramedullary Nail for Treatment of Periprosthetic Knee Infections: A Technique Worth Questioning.

Periprosthetic joint infections (PJIs) following total knee arthroplasty (TKA) are serious orthopaedic complications that pose marked burdens to both patients and health care systems. At our institution, two-stage exchange with a temporary short antibiotic cement-coated intramedullary nail was utilized for the treatment of repeat PJIs in a series of compromised patients with considerable bone loss. This study reports on (1) success rates, (2) functional and pain outcomes, (3) and complications for patients receiving a temporary short intramedullary nail for the treatment of PJI. Our institutional database was queried for all repeat knee PJI patients between March 1st, 2009 and February 28th, 2015. Patients with type II/III Anderson Orthopaedic Research Institute (AORI) bone defects who underwent two-stage exchange arthroplasty with a short antibiotic-coated intramedullary nail were included for analysis (n = 31). Treatment success was determined using the Delphi-based consensus definition of a successfully treated PJI: infection eradication (healed wound with no recurrence of infection by the same organism), no further surgical intervention for infection after reimplantation, and no PJI-related mortality. A paired t-test was performed to assess for continuous variables. A total of 26 patients went on to reimplantation, while 5 patients retained the intramedullary nail. Overall treatment success was 74.2%. Range of motion significantly decreased postoperatively (102.1 vs. 87.3 degrees; p < 0.001), while Knee Society Scores (function) significantly increased (55.6 vs. 77.7, p < 0.001). A majority of patients were full weight-bearing immediately following surgery (38.7%). Treating poor health status patients with PJI of the knee can be difficult after multiple revisions. With a success rate similar to conventional methods, our results demonstrate that two-stage exchange with a temporary short intramedullary nail may be a desirable treatment option for patients with bony defects wishing to avoid amputation or permanent arthrodesis. However, this method does not outperform other treatment modalities, and may not be suitable for all patients. Patient expectations and health status should be carefully assessed to determine if this procedure is appropriate in this complex patient population.

Risk factors for infection and amputation following open, combat-related calcaneal fractures.

BACKGROUND: High-energy open calcaneal fractures are severe injuries complicated by high rates of infection, uncertain functional outcomes, and frequent need for later amputation. METHODS: We conducted a retrospective review of 102 consecutive combat-related open calcaneal fractures. Patient demographics, injury mechanisms, fracture and wound characteristics, associated fractures, and methods of fracture fixation were reviewed to determine risk factors for eventual amputation or infection. RESULTS: Eighty-nine patients, with a mean age of twenty-six years, sustained 102 open calcaneal fractures (thirteen bilateral). After a mean follow-up of four years (range, five to ninety-two months), 42% (forty-three limbs) underwent amputation. A delayed amputation (more than twelve weeks from the time of injury) was performed in 15% (fifteen) of 102 open calcaneal fractures. In a multivariate Cox proportional-hazards survival model with time to amputation as the end point, the blast mechanism of injury, plantar wound location, larger size of open wound (in square centimeters), and escalating Gustilo and Anderson classification types (p < 0.05 for all) were predictive of eventual amputation. At the time of the final follow-up, patients who had undergone amputation had lower visual analogue scale scores for pain (2.1 compared with 4.0; p < 0.0001) and higher Tegner activity levels (5.4 compared with 3.5; p < 0.0001) than limb salvage patients. CONCLUSIONS: Lower-extremity amputation following open calcaneal fractures is predicted by the injury mechanism, wound location and size, and open fracture type and severity. After short-term follow-up, patients with open calcaneal fractures eventually requiring amputation exhibit improved pain and activity levels compared with patients with continued, ostensibly successful limb salvage.

Fibroregulation of mesenchymal progenitor cells by BMP-4 after traumatic muscle injury.

OBJECTIVES: Traumatized muscle is a complex healing environment containing cells with robust reparative and regenerative potential interacting in a cytokine milieu that influences the function and differentiation of these cells, leading to a spectrum of healing responses. In particular, bone morphogenetic protein-4 (BMP-4) is of interest as a potential modulator of healing because its dysregulation has been associated with fibrosis and heterotopic ossification formation. We propose a descriptive study of altered BMP-4 expression in traumatized muscle tissue and to evaluate its role in the fibroregulatory function of resident mesenchymal progenitor cells (MPCs) at the protein- and gene-expression levels. METHODS: Protein-level expression of BMP-4 from cells resident in traumatized muscle specimens was evaluated using ELISA and also using sodium dodecyl sulfate-polyacrylamide gel electrophoresis to compare BMP-4 in homogenized muscle tissue specimens. BMP-4, cartilage oligomeric matrix protein (COMP), and osteocalcin expression localization was analyzed via immunohistochemistry. Reverse transcription-polymerase chain reaction was performed to evaluate fibroregulatory gene expression in MPCs after treatment with BMP-4. RESULTS: BMP-4 was present in all traumatized muscle tissue specimens. Immunohistochemistry demonstrated that traumatized muscle fibers contained greater number of cells expressing BMP-4 in a more disorganized fashion compared with control samples. Reverse transcription-polymerase chain reaction demonstrated that COMP, growth and differentiation factor-10, and integrin beta-2 were up-regulated, whereas tumor necrosis factor-alpha was significantly down-regulated. COMP expression was colocalized in the traumatized muscle tissue with osteocalcin. CONCLUSIONS: BMP-4 has an effect on MPCs that seems to promote fibrotic tissue formation. These findings suggest that BMP-4, while promoting osteoinduction, may also act on MPCs to promote formation of a fibrotic osteoinductive matrix. Thus, this signaling axis might be a potential target for heterotopic ossification prevention.

Occult femoral neck fracture associated with vitamin D deficiency diagnosed by MRI: case report.

Hip fractures in the young are exceedingly rare and are usually seen in instances of high energy trauma or metabolically altered bone states. In this case report, we present an occult femoral neck fracture, diagnosed by magnetic resonance imaging, in an otherwise healthy, young, active duty male patient with an isolated vitamin D deficiency treated using cannulated percutaneous screws.

Heterotopic ossification following musculoskeletal trauma: modeling stem and progenitor cells in their microenvironment.

Heterotopic ossification (HO), characterized by the formation of mature bone in the soft tissues, is a complication that can accompany musculoskeletal injury, and it is a frequent occurrence within the military population that has experienced orthopaedic combat trauma. The etiology of this disease is largely unknown. Our laboratory has developed strategies to investigate the cellular and molecular events leading to HO using clinical specimens that were obtained during irrigation and debridement of musculoskeletal injuries. Our approach enables to study (1) the cell types that are responsible for pathological transformation and ossification, (2) the cell- and tissue-level signaling that induces the pathologic transformation, and (3) the effect of extracellular matrix topography and force transduction on HO progression. In this review, we will report on our findings in each of these aspects of HO etiology and describe our efforts to recapitulate our findings in an animal model for traumatic HO.