Intraoperative Acoustics: Auditory Cues in Hip Reconstructive Surgery.

Background: Orthopaedic surgeons rely on visual and tactile cues to guide performance in the operating room (OR). However, there is very little data on how sound changes during orthopaedic procedures and how surgeons incorporate audio feedback to guide performance. This study attempts to define meaningful changes in sound during vital aspects of total hip arthroplasty (THA) within the spectrum of human hearing. Methods: 84 audio recordings were obtained during primary elective THA procedures during sawing of the femoral neck, reaming of the acetabulum, acetabular cup impaction, polyethylene liner impaction, femoral broaching, planning of the femoral calcar and press-fit of a porous-coated stem in 14 patients. We graphed changes in frequency intensity across the human spectrum of hearing and sampled frequencies showing differences over time for statistically meaningful changes. Results: Sawing of the femoral neck, polyethylene impaction, and stem insertion showed significant temporal increases in overall sound intensity. Calcar planing showed a significant decrease in sound intensity. Moreover, spectrographic analysis showed that, for each of the critical tasks in THA, there were characteristic frequencies that showed maximal changes in loudness. These changes were above the 1 dB change in intensity required for detection by the human ear. Conclusion: Our results clearly demonstrate reproducible sound changes during total hip arthroplasty that are detectable by the human ear. Surgeons can incorporate sound as a valuable source of feedback while performing total hip arthroplasty to guide optimal performance in the OR. These findings can be extrapolated to other orthopaedic procedures that produce characteristic changes in sound. Moreover, it emphasizes the importance of limiting ambient noise in the OR that might make sound changes hard to distinguish.

A Consistent Anatomic Landmark for Identifying the Lateral Femoral Circumflex Artery in a Direct Anterior Hip Approach.

A direct anterior approach (DAA) is a technique practiced by arthroplasty surgeons that can be technically challenging, most notably for inexperienced surgeons. The lateral femoral circumflex artery (LFCA) is a branch of the femoral artery that crosses the surgical field during DAA and is an important landmark for superficial surgical dissection. If the vessel is not identified, significant bleeding may occur, and visualization may be impaired. This study aimed to develop a reliable method to identify and ligate the LFCA with minimal bleeding. First, a retrospective review was performed on a series of patients who underwent primary DAA total hip arthroplasty. Epidemiologic and intraoperative radiologic information was collected to determine the 2-dimensional location of the LFCA as it coursed through the surgical interval. Second, a series of computed tomography (CT) angiograms were compared to validate the intraoperative anatomic findings. In this study, 108 patients were evaluated fluoroscopically and 100 CT angiograms were obtained, for 208 total patients. The distance of the LFCA from the lesser trochanter with standard fluoroscopy (LT/TD) was 0.600 vs 0.438 on CT angiogram. Mean offset from midline (offset/femur diameter) was 0.166 lateral to midline vs 0.36 medial to midline. Median value of offset was 0 vs 0.411-representing a position on the anatomic axis of the femur. This study confirmed that the LFCA is found approximately one-third to two-thirds of the way between the lesser and greater trochanters along the anatomic axis of the femur for most patients. Surgeons who are new to DAA can use the LFCA as a reliable landmark to confirm the correct interval. [Orthopedics. 2022;45(5):262-268.].

Socioeconomic Status Is Associated with Risk of Above-knee Amputation After Periprosthetic Joint Infection of the Knee.

BACKGROUND: Above-knee amputation (AKA) is a severe but rare complication of TKA. Recent evidence suggests there are sex and racial disparities with regard to AKA after TKA. However, whether lower socioeconomic status is associated with an increased risk of AKA after TKA has not been conclusively established. QUESTIONS/PURPOSES: (1) Is low socioeconomic status or use of public health insurance plans associated with an increased risk of AKA after periprosthetic joint infection (PJI) of the knee? (2) Is race or sex associated with an increased risk of AKA after PJI of the knee? METHODS: This cross-sectional study screened the National Inpatient Sample (NIS) between 2010 and 2014 using the International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) procedure and diagnosis codes to identify 912 AKAs (ICD 84.17) among 32,907 PJIs of the knee. The NIS is a large national database of inpatient hospitalizations frequently used by researchers to study outcomes and trends in orthopaedic procedures. The NIS was selected over other databases with more complete followup data such as the American College of Surgeons National Surgical Quality Improvement Program (ACS NSQIP) due to its unique ability to examine income levels and insurance type. Cases were identified by taking all patients with an ICD diagnosis code related to PJI of the knee and limiting that cohort to patients with an ICD procedure code specific to TKA. A total of 912 AKAs after PJI were identified (912 of 32,907, [3%] of all PJIs of the knee) with males comprising 52% of the AKA sample (p = 0.196). Multivariate logistic regression was used to compare risk of AKA after PJI of the knee after controlling for patient demographics, hospital characteristics, and comorbidities. RESULTS: Compared with the wealthiest income quartile by ZIP code, patients in the lowest income quartile by ZIP code were more likely to sustain an AKA (OR = 1.58; 95% confidence interval [CI] 1.25-1.98; p < 0.001). Compared with patients with private insurance, patients with Medicare (OR = 1.94; 95% CI, 1.55-2.43; p < 0.001) and Medicaid (OR = 1.86; 95% CI, 1.37-2.53; p < 0.001) were at higher risk of AKA. There were no differences with regard to risk of AKA for white patients (670 of 24,004 [3%]; OR = 0.99; 95% CI, 0.77-1.26; p = 0.936) and black patients (95 of 3178 [3%], OR = 0.95; 95% CI, 0.69-1.30; p = 0.751) when compared with others (reference, 83 of 3159 [3%]). When compared with female patients, male patients did not have a greater risk of undergoing AKA (OR = 1.02; 95% CI, 0.88-1.29; p = 0.818). CONCLUSIONS: This study did not observe any racial or sex disparities with regard to risk of AKA after PJI. However, there was a greater risk of AKA after PJI for poorer patients and patients participating in Medicare or Medicaid insurance plans. Surgeons should be cognizant when treating PJI in patients from lower income backgrounds as these patients may be at greater risk for AKA. Future research should explore the role of physician attitudes or preconceptions about predicted patient followup in treating PJI, as well as the effect of concurrent peripheral vascular disease on the risk of AKA after PJI. LEVEL OF EVIDENCE: Level III, therapeutic study.

Cementless femoral fixation in total hip arthroplasty.

A number of cementless femoral stems are associated with excellent long-term survivorship. Cementless designs differ from one another in terms of geometry and the means of obtaining initial fixation. Strict classification of stem designs is important in order to compare results among series. Loosening and thigh pain are less prevalent with modern stem designs. Stress-shielding is present in most cases, even with newer stem designs.

Knee arthrotomy repair with a continuous barbed suture: a biomechanical study.

We compared knee arthrotomy closures using interrupted biodegradable sutures and running bidirectionally barbed sutures in cadaveric specimens subjected to cyclic loading. During the initial 2000 flexion cycles, both groups maintained closure and no suture ruptured. Suture throws were then sequentially cut to weaken the repairs, and the knees were cyclically flexed after each cut. Both types of suture repairs survived the cutting of the first throw or stitch and subsequent cyclical testing. However, there was a significant difference in the repairs after multiple cuts (log-rank test, P < .003). None of the knees in the interrupted suture group survived more than 3 cuts, whereas in the barbed repair group, it took the severing of as many as 7 throws for failure to occur.

Chronic expanding hematoma of the lateral thigh and massive bony destruction after a failed total hip arthroplasty.

Pseudotumors have been described around both stable and failed total hip arthroplasties. The causes are varied and include polyethylene debris and masses associated with metal-on-metal bearings. We present a patient with a massive tumor of the thigh that grossly and pathologically was associated with recurrent bleeding and extensive bony destruction. The characteristics of this tumor most resemble those of a chronic expanding hematoma. To our knowledge, this has not previously been reported in association with a total hip arthroplasty.