The objective of this study was to use patient-specific finite element modeling to measure the 3D interfragmentary strain environment in clinically realistic fractures. The hypothesis was that in the early post-operative period, the tissues in and around the fracture gap can tolerate a state of strain in excess of 10%, the classical limit proposed in the Perren strain theory.

Eight patients (6 males, 2 females; ages 22–95 years) with distal femur fractures (OTA/AO 33-A/B/C) treated in a Level I trauma center were retrospectively identified. All were treated with lateral bridge plating. Preoperative computed tomography scans and post-operative X-rays were used to create the reduced fracture models. Patient-specific materials properties and loading conditions (20%, 60%, and 100% body weight (BW)) were applied following our published method.[1]

Elements with von Mises strains >10% are shown in the 100% BW loading condition. For all three loading scenarios, as the bridge span increased, so did the maximum von Mises strain within the strain visualization region. The average gap closing (Perren) strain (mean ± SD) for all patient-specific models at each body weight (20%, 60%, and 100%) was 8.6% ± 3.9%, 25.8% ± 33.9%, and 39.3% ± 33.9%, while the corresponding max von Mises strains were 42.0% ± 29%, 110.7% ± 32.7%, and 168.4% ± 31.9%. Strains in and around the fracture gap stayed in the 2–10% range only for the lowest load application level (20% BW).

Moderate loading of 60% BW and above caused gap strains that far exceeded the upper limit of the classical strain rule (<10% strain for bone healing). Since all of the included patients achieved successful unions, these findings suggest that healing of distal femur fractures may be robust to localized strains greater than 10%.

There is a paucity of available literature to guide the surgeon treating postoperative fractures of the greater trochanter after femoral component revision. Between 2009 and 2016, 133 patients underwent femoral component revision by the senior author utilizing a modular tapered fluted titanium stem. 17 patients died or had inadequate follow-up. Therefore, 116 patients were included in the final analysis. There were 58 males and 58 females with a mean age of 64 (range 23 to 91 years old). Clinical and radiographic data were analyzed for postoperative greater trochanteric fracture (GTfx). Mean clinical follow up was 21 months (range 3 to 77 mos). Age, BMI, preoperative diagnosis, comorbidities, reason for revision, use of Extended Trochanteric Osteotomy (ETO), fixation method of ETO, presence of prior hardware, post-operative trauma (falls), femoral component size and offset, change in leg length were analyzed to determine potential risk factors for postoperative GT fracture.

There were 7 postoperative greater trochanteric fractures in 7 patients (6%). Of these, 1 occurred as a result of a postoperative fall, 1 occurred after dislocation, and 1 occurred after a fall with a subsequent dislocation. The mean time to diagnosis of the fracture was 10.7 weeks postoperatively (range one day to 37.4 weeks). 52 of 116 patients had their revision performed through an ETO. Of those, 6 had a postoperative fracture of the GT. The use of an ETO significantly increased the likelihood of postoperative GT fx (p=0.035). Regarding femoral component size, use of a longer proximal body (+10 or greater) was associated with an increased risk of postoperative GT fx (p=0.07).

Two fractures were minimally (<1cm) or non-displaced and were treated non-operatively. Of these fractures, 1 united. The other fracture further displaced and resulted in recurrent instability. This was treated with excision of the fragment and a constrained liner. 5 fractures were displaced and were treated with ORIF. 3 were fixed with a cable grip device, 1 was plated, and 1 was treated with a cable grip device and a constrained liner. Of those treated with some form of ORIF, all 5 healed. Of those that underwent surgical fixation initially, 3 reported residual trochanteric pain and 1 patient had their hardware removed (trochanteric claw). 2 of these patients have a residual limp and require a cane for use as a gait aid. The patient treated non-surgically required a cane as did the patient that failed non-surgical treatment.

Post-operative greater trochanteric fractures are a rare complication of femoral component revision. The use of an ETO significantly increased the rate of post of GTfx. The mean time to diagnosis of was 11 weeks. Displaced fractures of the greater trochanter treated with ORIF all healed, both cable grip devices and plates were effective. Residual limp requiring gait aids and residual trochanteric pain were common outcomes after fixation of these fractures despite successful union.

Not all patients receive enhanced mobility and return to comfortable, independent living after Total Hip Arthroplasty (THA). It would be beneficial to both surgeons and patients to be able to predict short term outcomes for THA. The purpose of this study was to investigate factors affecting the short term outcome of primary THA and develop a multivariate regression model that can predict such outcomes.

This was a prospective study of 101 patients, who underwent primary THA. All patients were followed for a minimum of 1 year. 12 independent variables, including age, gender, diagnosis, presence of preoperative comorbidities, BMI, preoperative WOMAC physical component (PC) score, type of anesthesia, type of fixation, surgical time, estimated blood loss, use of a postoperative drain, and length of stay were analyzed using correlation and multivariate regression analyses. Multivariate regression models were validated using an independent cohort.

Correlation analyses showed three variables significantly influence short term THA outcome. These include preoperative WOMAC PC score (PC) (p< 0.01), gender (G) (p= 0.01) and the presence of preoperative comorbidities (CMB) (p= 0.02). By multivariate regression analysis, the following regression model was obtained: Outcome = PC*0.45 −G*9 + CMB*8 + 62.

This model exhibited positive correlation (R2=.25) when compared to a separate cohort of 27 patients undergoing THA not included in the original equation derivation.

Our multivariate regression analysis has yielded statistical, multivariate confirmation or non-confirmation of common, predictive THA factors that have previously been reported in the literature. This study provides a concrete, statistically significant measure indicating that preoperative WOMAC PC score, gender, and the presence of preoperative comorbidities are predictive factors for short term primary THA outcome. Finally, our multivariate regression equation can be used to predict the general short term patient outcome following primary THA.

Purpose: Patients undergoing total knee arthroplasty (TKA) often experience a difficult recovery due to severe post-operative pain. Utilizing a multi-modal pain management protocol, a blinded, randomized, placebo-controlled study was designed to evaluate the efficacy of patient selected music on reducing perceived pain.

Method: Using a standardized intra-operative anesthetic protocol and postoperative pain management protocol, consented patients were randomized into either: 1) the interventional Music group (noise-reduction headphones, patient choice/classical music) or the control, Non-Music group (noise-reduction headphones only). Pain scores, aided by the Wong-Baker and Verbal Descriptor scales, were assessed via the Visual Analog Scale (VAS) at baseline and postoperatively at 3, 6, and 24 hours. A paired Student’s t-test was utilized to determine statistical significance, which was set at a p < 0.05.

Results: Thirty subjects were enrolled. At baseline, there were no statistical differences in mean pain between the study (2.29 ± 2.78) and the control (3.34 ± 2.67) groups (p = 0.19). Mean pain scores reported the Music group to have significantly less pain at 3 hours (1.49 ± 1.39 vs. 3.87 ± 3.44, p = 0.01), and at 24 hours (2.41 ± 1.67 vs. 4.03 ± 2.89, p=0.04).

Conclusion: Intraoperative music provides an inexpensive, non-invasive method of lowering perceived postoperative pain for patients undergoing a TKA. The results of this study offer a glimpse into how an alternative therapy or non-pharmacologic method can reduce postoperative pain. A larger-scale, higher powered trial may demonstrate how music could favorably affect secondary outcomes such as patient satisfaction, range of motion, and length of stay.