Mortality During Total Hip Periprosthetic Joint Infection.

BACKGROUND: We sought to understand the mortality rate of periprosthetic joint infection (PJI) of the hip undergoing 2-stage revision for infection. METHODS: Database search, yielding 23 relevant studies, totaled 19,169 patients who underwent revision for total hip PJI. RESULTS: One-year weighted mortality rate was 4.22% after total hip PJI. Five-year mortality was 21.12%. Average age was 65 years. When comparing the national age-adjusted risk of mortality and the reported 1-year mortality risk in this systematic review, the risk of death after total hip PJI is significantly increased (odds ratio 3.58, P < .001). CONCLUSION: The mortality rate during total hip revision for infection is high. When counseling a patient regarding complications of this disease, death should be discussed.

Mortality During Total Knee Periprosthetic Joint Infection.

BACKGROUND: Periprosthetic joint infections (PJIs) are fraught with multiple complications including poor patient-reported outcomes, disability, reinfection, disarticulation, and even death. We sought to perform a systematic review asking the question: (1) What is the mortality rate of a PJI of the knee undergoing 2-stage revision for infection? (2) Has this rate improved over time? (3) How does this compare to a normal cohort of individuals? METHODS: We performed a database search in MEDLINE/EMBASE, PubMed, and all relevant reference studies using the following keywords: "periprosthetic joint infection," "mortality rates," "total knee arthroplasty," and "outcomes after two stage revision." Two hundred forty-two relevant studies and citations were identified, and 14 studies were extracted and included in the review. RESULTS: A total of 20,719 patients underwent 2-stage revision for total knee PJI. Average age was 66 years. Mean mortality percentage reported was 14.4% (1.7%-34.0%) with average follow-up 3.8 years (0.25-9 years). One-year mortality rate was 4.33% (3.14%-5.51%) after total knee PJI with an increase of 3.13% per year mortality thereafter (r = 0.76 [0.49, 0.90], P < .001). Five-year mortality was 21.64%. When comparing the national age-adjusted mortality (Actuarial Life Table) and the reported 1-year mortality risk in this meta-analysis, the risk of death after total knee PJI is significantly increased, with an odds ratio of 3.05 (95% confidence interval, 2.69-3.44; P < .001). CONCLUSION: The mortality rate after 2-stage total knee revision for infection is very high. When counseling a patient regarding complications of this disease, death should be discussed.

Perivascular Stem Cells Diminish Muscle Atrophy Following Massive Rotator Cuff Tears in a Small Animal Model.

BACKGROUND: Rotator cuff tears are a common cause of shoulder pain and often necessitate operative repair. Muscle atrophy, fibrosis, and fatty infiltration can develop after rotator cuff tears, which may compromise surgical outcomes. This study investigated the regenerative potential of 2 human adipose-derived progenitor cell lineages in a murine model of massive rotator cuff tears. METHODS: Ninety immunodeficient mice were used (15 groups of 6 mice). Mice were assigned to 1 of 3 surgical procedures: sham, supraspinatus and infraspinatus tendon transection (TT), or TT and denervation via suprascapular nerve transection (TT + DN). Perivascular stem cells (PSCs) were harvested from human lipoaspirate and sorted using fluorescence-activated cell sorting into pericytes (CD146 CD34 CD45 CD31) and adventitial cells (CD146 CD34 CD45 CD31). Mice received no injection, injection with saline solution, or injection with pericytes or adventitial cells either at the time of the index procedure ("prophylactic") or at 2 weeks following the index surgery ("therapeutic"). Muscles were harvested 6 weeks following the index procedure. Wet muscle weight, muscle fiber cross-sectional area, fibrosis, and fatty infiltration were analyzed. RESULTS: PSC treatment after TT (prophylactic or therapeutic injections) and after TT + DN (therapeutic injections) resulted in less muscle weight loss and greater muscle fiber cross-sectional area than was demonstrated for controls (p < 0.05). The TT + DN groups treated with pericytes at either time point or with adventitial cells at 2 weeks postoperatively had less fibrosis than the TT + DN controls. There was less fatty infiltration in the TT groups treated with pericytes at either time point or with adventitial cells at the time of surgery compared with controls. CONCLUSIONS: Our findings demonstrated significantly less muscle atrophy in the groups treated with PSCs compared with controls. This suggests that the use of PSCs may have a role in the prevention of muscle atrophy without leading to increased fibrosis or fatty infiltration. CLINICAL RELEVANCE: Improved muscle quality in the setting of rotator cuff tears may increase the success rates of surgical repair and lead to superior clinical outcomes.

What is the frequency of vascular injury after knee dislocation?

BACKGROUND: Vascular injury secondary to an acute knee dislocation is a known complication. However, there exist wide discrepancies in the reported rate of vascular injury in this setting. QUESTIONS/PURPOSES: Using a large private insurance database, we determined the frequency of vascular injury in knee dislocations across year of diagnosis, age, sex, and US geographic region and the proportion of these injuries requiring surgical repair. METHODS: The PearlDiver database, which contains records from 11 million orthopaedic patients, was searched using ICD-9 diagnostic codes for all knee dislocation events from 2004 to 2009. Within this subset, we identified which knee dislocations had an associated vascular injury ICD-9 code. Patients were stratified by year of diagnosis, age, sex, and US geographic region, and Current Procedural Terminology codes were used to identify the subset of patients with vascular injury requiring surgical repair. Differences in frequency across demographic groups and over time were analyzed with Poisson regression analysis. RESULTS: Among the 8050 limbs with knee dislocation identified over the study period, 267 had a concomitant vascular injury for an overall frequency of 3.3%. Males were found to have an increased risk of vascular injury compared to females (odds ratio = 2.59, p < 0.001). Additionally, patients aged 20 to 39 years had a higher risk of vascular injury when compared to those aged 0 to 19 years (odds ratio = 1.93, p = 0.001), 40 to 59 years (odds ratio = 1.57, p = 0.014), and 60 years or older (odds ratio = 2.81, p = 0.036). There were no differences in vascular injury frequency across US geographic regions or diagnosis year. Thirty-four of the 267 cases of vascular injury (13%) underwent surgical treatment. CONCLUSIONS: This is the largest study, to our knowledge, that analyzes the proportion of knee dislocations that result in vascular injury. Our data suggest that there is a lower frequency of vascular injury associated with knee dislocation and a lower proportion of vascular injuries undergoing surgical treatment than previously reported. These findings may support a more selective angiography protocol to screen for vascular injury, rather than performing this invasive diagnostic test on all knee dislocations, as has been done historically. Future large-scale and prospective studies should analyze factors that may predispose to vascular injuries after knee dislocation and determine which patients should be screened for vascular injury after knee dislocation. LEVEL OF EVIDENCE: Level IV, prognostic study. See Instructions for Authors for a complete description of levels of evidence.