Pre-Operative Predictors for Discharge to Post-Acute Care Facilities After Total Knee Arthroplasty.

BACKGROUND: Joint replacement surgery is in increasing demand and is the most common inpatient surgery for Medicare beneficiaries. The venue for post-operative rehabilitation, including early outpatient therapy after surgery, influences recovery and quality of life. As part of a comprehensive total joint program at Kaiser Permanente Colorado, we developed and validated a predictive model to anticipate and plan the disposition for rehabilitation of our patients after total knee arthroplasty (TKA). METHODS: We analyzed data for TKA patients who completed a pre-operative Total Knee Risk Assessment in 2017 (the model development cohort) or during the first 6 months of 2018 (the model validation cohort). The Total Knee Risk Assessment, which is used to guide disposition for rehabilitation, included questions in mobility, social, and environment domains. Multivariable logistic regression was used to predict discharge to post-acute care facilities (PACFs) (ie, skilled nursing facilities or acute rehabilitation centers). RESULTS: Data for a total of 1481 and 631 patients who underwent TKA were analyzed in the development and validation cohorts, respectively. Ninety-three patients (6.3%) in the development cohort and 22 patients (3.5%) in the validation cohort were discharged to PACFs. Eight risk factors for discharge to PACFs were included in the final multivariable model. Patients with a diagnosis of neurological disorder and with a mobility/balance issue had the greatest chance of discharge to PACFs. CONCLUSION: This validated predictive model for discharge disposition following TKA may be used as a tool in shared decision-making and discharge planning for patients undergoing TKA.

The past and future of peri-operative interventions to reduce arthrogenic quadriceps muscle inhibition after total knee arthroplasty: A narrative review.

Total knee arthroplasty (TKA) improves patient-reported function by alleviating joint pain, however the surgical trauma exacerbates already impaired muscle function, which leads to further muscle weakness and disability after surgery. This early postoperative strength loss indicates a massive neural inhibition and is primarily driven by a deficit in quadriceps muscle activation, a process known as arthrogenic muscle inhibition (AMI). To enhance acute recovery of quadriceps muscle function and long-term rehabilitation of individuals after TKA, AMI must be significantly reduced in the early post-operative period. The aim of this narrative review is to review and discuss previous efforts to mitigate AMI after TKA and to suggest new approaches and interventions for future efficacy evaluation. Several strategies have been explored to reduce the degree of post-operative quadriceps AMI and improve strength recovery after TKA by targeting post-operative swelling and inflammation or changing neural discharge. A challenge of this work is the ability to directly measure AMI and relevant contributing factors. For this review we focused on interventions that aimed to reduce post-operative swelling or improve knee extension strength or quadriceps muscle activation measured by twitch interpolation. For individuals undergoing TKA, the use of anti-inflammatory medications, tranexamic acid, cryotherapy, intra-articular drains, torniquets, and minimally invasive surgical techniques for TKA have limited benefit in attenuating quadriceps AMI early after surgery. However, interventions such as inelastic compression garments, voluntary muscle contractions, and neuro-muscular electrical stimulation show promise in mitigating or circumventing AMI and should continue to be refined and explored.

Obesity and osteoarthritis: more than just wear and tear.

A link has been established between obesity and osteoarthritis (OA), but the precise relationship has yet to be defined. OA has a multifactorial etiology, and obesity is consistently identified as an independent and modifiable risk factor. The biomechanical relationship is intuitive: increased loads on articular cartilage cause subsequent wear and cartilage breakdown. Less intuitive, and possibly more important, are the systemic effects of obesity on OA. Promising investigations into relationships between lipid metabolism and OA have been rarely reported in the orthopaedic literature. These reports argue that, in obese patients, weight loss may not only help prevent OA but also may be an effective treatment strategy. Orthopaedic surgeons should be aware of the biomechanical and systemic implications of obesity with respect to OA so that patients may be counseled accordingly.

Biomechanical evaluation of a unicortical button versus interference screw for subpectoral biceps tenodesis.

PURPOSE: The purpose of this study was to evaluate and compare the biomechanical properties of a unicortical button with an interference screw used for subpectoral biceps tenodesis. We also describe the anatomic dangers of bicortical button use in the subpectoral location. METHODS: Twenty-eight fresh-frozen human cadaveric shoulders with a mean age of 52 years were studied. The specimens were randomly divided into 4 experimental biceps tenodesis groups (n = 7): unicortical button, interference screw, bicortical suspensory button, and bicortical suspensory with interference screw (Arthrex, Naples, FL). Each tenodesis specimen was mounted on a mechanical testing machine, preloaded for 2 minutes at 5 N, cycled from 5 to 70 N for 500 cycles (1 Hz), and loaded to failure (1 mm/s). We determined the mode of failure and computed the ultimate load to failure, yield load, pullout stiffness, and displacement at peak load. Calculations of the distance between the axillary and radial nerves with respect to the bicortical buttons were also calculated in 6 specimens. RESULTS: There was no statistically significant difference (P > .05) among groups in terms of age, ultimate load to failure, pullout stiffness, or displacement at peak load. Suture-tendon interface failure was the most commonly observed mode of failure. The axillary nerve was on average 7.8 mm from the bicortical button; however, in 6 specimens the nerve was less than 3 mm away. CONCLUSIONS: The use of a unicortical button for subpectoral biceps tenodesis provides biomechanical properties similar to the use of an interference screw. In addition, the use of a bicortical button in this area of the proximal humerus puts the axillary nerve at risk. CLINICAL RELEVANCE: Using a unicortical button subpectoral biceps method may provide a surgeon with a safe and technically easy and reproducible technique while providing similar biomechanical properties to a known standard implant.

Cefazolin vs Second-line Antibiotics for Surgical Site Infection Prevention After Total Joint Arthroplasty Among Patients With a Beta-lactam Allergy.

Background: Cefazolin is a first-line agent for prevention of surgical site infections (SSIs) after total joint arthroplasty. Patients labeled allergic to beta-lactam antibiotics frequently receive clindamycin or vancomycin perioperatively due to the perceived risk of a hypersensitivity reaction after exposure to cefazolin. Methods: This single-system retrospective review included patients labeled allergic to penicillin or cephalosporin antibiotics who underwent a primary total hip and/or knee arthroplasty between January 2020 and July 2021. A detailed chart review was performed to compare the frequency of SSI within 90 days of surgery and interoperative hypersensitivity reactions (HSRs) between patients receiving cefazolin and patients receiving clindamycin and/or vancomycin. Results: A total of 1128 hip and/or knee arthroplasties from 1047 patients were included in the analysis (cefazolin n = 809, clindamycin/vancomycin n = 319). More patients in the clindamycin and/or vancomycin group had a history of cephalosporin allergy and allergic reactions with immediate symptoms. There were fewer SSIs in the cefazolin group compared with the clindamycin and/or vancomycin group (0.9% vs 3.8%; P < .001) including fewer prosthetic joint infections (0.1% vs 1.9%). The frequency of interoperative HSRs was not different between groups (cefazolin = 0.2% vs clindamycin/vancomycin = 1.3%; P = .06). Conclusions: The use of cefazolin as a perioperative antibiotic for infection prophylaxis in total joint arthroplasty in patients labeled beta-lactam allergic is associated with decreased postoperative SSI without an increase in interoperative HSR.

Extensive heterotopic ossification after suspensory cortical fixation of acute distal biceps tendon ruptures.

Suspensory cortical fixation is commonly used for distal biceps tendon repair and reconstruction with one of several commercially available devices. The single-incision approach typically used with these devices is believed to have a lower incidence of heterotopic ossification than the dual-incision technique, but the true incidence of heterotopic ossification is unknown. The role of chemotherapeutic or radiation prophylaxis is undefined. We have identified 4 cases of extensive heterotopic ossification after biceps fixation with a suspensory button and single-incision approach. Surgeons should be aware of this potential complication when using suspensory cortical buttons for distal biceps fixation.

Reliability and accuracy of digital templating for the humeral component of total shoulder arthroplasty.

BACKGROUND: This experimental study evaluated the interobserver reliability and accuracy of pre-operative digital templating for humeral head size, stem size and neck angle for total shoulder arthroplasty. METHODS: Twenty-five patients underwent a total shoulder arthroplasty with a single prosthesis. Four independent, blinded surgeons (two experienced shoulder surgeons and two PGY-6 fellows) used pre-operative radiographs and templating software to generate templates of the humeral head, stem and neck for each patient. Interobserver reliability was calculated using weighted kappa (κ) analysis. Accuracy was assessed by comparing templates to actual implant sizes. RESULTS: Interobserver reliability was fair to substantial (κ = 0.26 to 0.71) for head size, fair to substantial (κ = 0.39 to 0.72) for stem size and slight to fair (κ = 0.16 to 0.34) for neck angle. Templated head size, stem size and neck angle had accuracies of 53%, 77% and 68% within one size variation, respectively. Experience did not affect accuracy (p = 0.11 to 0.48). CONCLUSIONS: Digital templating is not a useful guide for pre-operative surgical planning and should not be used to select a prosthesis.

Quadriceps tendon injuries in national football league players.

BACKGROUND: Distal quadriceps tendon tears are uncommon injuries that typically occur in patients older than 40 years of age, and they have a guarded prognosis. Predisposing factors, prodromal findings, mechanisms of injury, treatment guidelines, and recovery expectations are not well described in high-level athletes. HYPOTHESIS: Professional American football players with an isolated tear of the quadriceps tendon treated with timely surgical repair will return to their sport. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: Fourteen unilateral distal quadriceps tendon tears were identified in National Football League (NFL) players from 1994 to 2004. Team physicians retrospectively reviewed training room and clinic records, operative notes, and imaging studies for each of these players. Data on each player were analyzed to identify variables predicting return to play. A successful outcome was defined as returning to play in regular-season NFL games. RESULTS: Eccentric contraction of the quadriceps was the most common mechanism of injury, occurring in 10 players. Only 1 player had antecedent ipsilateral extensor mechanism symptoms. Eleven players had a complete rupture of the quadriceps tendon, and 3 had partial tears. There were no associated knee injuries. All ruptures were treated with surgical repair, 1 of which was delayed after failure of nonoperative treatment. Fifty percent of players returned to play in regular-season NFL games. There was a trend toward earlier draft status for those who returned to play compared with those who did not (draft round, 3.1 ± 2.5 vs. 6.0 ± 2.9, respectively; P = .073). For those who returned to play, the average number of games after injury was 40.9 (range, 12-92). CONCLUSION: Quadriceps tendon tears are rare in professional American football players, and they usually occur from eccentric load on the extensor mechanism. Prodromal symptoms and predisposing factors are usually absent. Even with timely surgical repair, there is a low rate of return to play in regular-season games. There is a trend toward early draft rounds for those who successfully return to play.

Are conventional reconstruction plates equivalent to precontoured locking plates for distal humerus fracture fixation? A biomechanics cadaver study.

BACKGROUND: The optimal plate type and configuration for distal humerus fracture fixation has yet to be defined. Available biomechanical studies show conflicting results. No existing studies compare conventional reconstruction plates to newer precontoured distal humerus locking plates in both parallel and perpendicular configurations. METHODS: Three groups of humerus specimens were compared via biomechanical testing in a cadaver model simulating metaphyseal comminution. Group 1 consisted of conventional reconstruction plates in a perpendicular configuration. Group 2 used precontoured locking plates in a perpendicular configuration. Group 3 used precontoured locking plates in a parallel configuration. Each group was tested for stiffness in anterior bending, posterior bending, axial compression, and torsion. The specimens then underwent cyclic loading followed by single load to failure in posterior bending. FINDINGS: There was no significant difference between the three groups for anterior bending, posterior bending, axial compression, or torsional stiffness. There was no significant difference in load to failure for any of the three groups. Screw loosening was significantly higher in Group 1 when compared to Groups 2 and 3 after cyclic loading. INTERPRETATION: In the early postoperative period, less expensive perpendicular conventional reconstruction plate constructs provide similar stiffness and load to failure properties to newer precontoured locking plate systems regardless of plate configuration.