Influence of increasing construct constraint in the presence of posterolateral deficiency at knee replacement: A biomechanical study

When faced with posterolateral corner (PLC) deficiency, surgeons must choose a total knee replacement (TKR) construct that provides the appropriate level of constraint. This should match the internal constraint of the device to the soft tissue host laxity pattern. Little guidance is available peroperatively, with factors influencing final component choice remaining ill defined. This study aimed to quantify the effect of PLC insufficiency on the “envelope of laxity” (EoL) after TKR and the effect of increasingly component constraint upon knee behavior through a functional arc of flexion. Using computer navigation, mixed effect modeling and loaded cadaveric legs—laxity was quantified under separate states: the native knee, after implantation of a posterior stabilized (PS)‐TKR, after sectioning the lateral (fibular) collateral ligament and popliteus tendon (PS‐TKR‐PLC), and after re‐implantation with a semi‐constrained “total stabilized” knee replacement (TS‐TKR). Laxity was quantified from 0 to 110° of flexion for anterior draw, varus–valgus, and internal–external rotation. Implantation of the PS‐TKR was consistently associated with increased constraint when compared to the native knee. PLC sectioning led to significantly increased laxity during varus stress from mid to deep flexion. Revision to a TS‐TKR construct restored constraint mimicking that of the primary state but only for the arc of motion 0–90°. In a posterolateral deficient state, a fixed bearing semi‐constrained TS‐TKR restored the knee to near normal kinematics but this was only achieved from an arc of motion 0–90° of flexion. At higher flexion angles, there remained an unfavorable laxity pattern with varus stress opening. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:427–434, 2016.     

Punishment Learning in U.S. Veterans With Posttraumatic Stress Disorder

Learning processes have been implicated in the development and course of posttraumatic stress disorder (PTSD); however, little is currently known about punishment‐based learning in PTSD. The current study investigated impairments in punishment‐based learning in U.S. veterans. We expected that veterans with PTSD would demonstrate greater punishment‐based learning compared to a non‐PTSD control group. We compared a PTSD group with and without co‐occurring depression (n = 27) to a control group (with and without trauma exposure) without PTSD or depression (n = 29). Participants completed a computerized probabilistic punishment‐based learning task. Compared to the non‐PTSD control group, veterans with PTSD showed significantly greater punishment‐based learning. Specifically, there was a significant Block × Group interaction, F(1, 54) = 4.12, p = .047, η² = .07. Veterans with PTSD demonstrated greater change in response bias for responding toward a less frequently punished stimulus across blocks. The observed hypersensitivity to punishment in individuals with PTSD may contribute to avoidant responses that are not specific to trauma cues.     

Predictors and outcomes of unplanned early rehospitalization in the first year following lung transplantation

Unplanned early rehospitalization (UER), defined as an unscheduled admission within 30 days of a hospital discharge, is associated with graft loss and recipient mortality in some solid organ transplants but has not been investigated in lung transplant. In this retrospective study, we collected socio‐demographic and clinical factors to determine predictors and outcomes of UER in the first year following lung transplantation. There were 193 patients who underwent lung transplantation and survived to discharge during the 7.9‐year study period. There were 116 (60.1%) patients with at least one UER. Infections (32.8%) and post‐surgical complications (11.8%) were the most common reasons for UER. On multivariate analysis, the strongest predictor of having an UER was discharge to a long‐term acute care facility (odds ratio: 3.01, 95% confidence interval [CI] 1.46–6.20; P=.003). Patients with any UER in the first year following transplantation had worse adjusted survival (hazard ratio: 1.89, 95% CI 1.02–3.50; P=.04). It is unclear, however, to what extent UERs reflect preventable outcomes. Further large‐scale, prospective research is needed to identify the extent to which certain types of UER are modifiable and to define patients at high‐risk for preventable UER.     

CA19-9 Normalization During Pre-operative Treatment Predicts Longer Survival for Patients with Locally Progressed Pancreatic Cancer

Background

Compared to the widely adopted 2–4 months of pre-operative therapy for patients with borderline resectable (BR) or locally advanced (LA) pancreatic ductal adenocarcinoma (PDAC), our institution tends to administer a longer duration before considering surgical resection. Using this unique approach, the aim of this study was to determine pre-operative variables associated with survival.

Methods

Records from patients with BR/LA PDAC who underwent attempt at surgical resection from 1992–2014 were reviewed.

Results

After a median duration of 6 months of pre-operative treatment, 109 patients with BR/LA PDAC (BR 63, LA 46) were explored; 93 (85.3 %) underwent pancreatectomy. Those who received at least 6 months of pre-operative treatment had longer median overall survival (OS) than those who received less (52.8 vs. 32.1 months, P?=?0.044). On multivariate analysis, pre-operative treatment duration was the strongest predictor of survival (hazard ratio (HR) 4.79, P?=?0.043). However, OS was similar in those whose CA19-9 normalized regardless of whether they received more or less than 6 months of chemotherapy (71.4 vs. 101.8 months, P?=?0.930).

Conclusions

Pre-operative CA19-9 decline can guide treatment duration in patients with BR/LA PDAC. We endorse 6 months of therapy except in those patients whose values normalize, where surgery can be considered after a shorter course.

     

A Pre-Hospital Patient Education Program Improves Outcomes of Bariatric Surgery

Background

We designed an assessment and education program which was delivered to patients prior to first outpatient appointment for bariatric surgery. We hypothesised that this program would streamline care and would lead to improved weight loss following bariatric surgery.

Methods

The program incorporates a structured general practitioners (GP) review, a patient information evening and an on-line learning package. It was introduced in September 2012. Patient flow through the program was recorded. Outcomes of the new program were compared with contemporaneously treated patients who did not undertake the pre-hospital program.

Results

All 636 patients on the waiting list for first appointment at the Alfred Health bariatric surgery clinic were invited to participate. There were 400 patients ultimately removed from the waiting list for first appointment. Of the remaining 236 patients, 229 consented to participate in the new program. The mean BMI was 47.8?±?9.2. The fail to attend first appointment rate dropped from 12 to 2.1 %. At 12 months post-bariatric surgery, patients who undertook the new program (n?=?82) had a mean excess weight loss (EWL) of 41.1?±?20.3 % where as those treated on the standard pathway (n?=?61) had a mean EWL 32?±?18.0 % (p?=?0.012).

Conclusions

The introduction of a pre-hospital education program has led to an improvement in attendance rates and early weight loss post-bariatric surgery.

     

The role of the rotating hinge prosthesis in the salvage arthroplasty setting

We have studied a consecutive series of 72 salvage knee procedures using a Kinematic rotating hinge prosthesis performed in a single arthroplasty unit between 1983 and 1997. Clinical and radiographic assessment of the survivorship of the Kinematic rotating hinge total knee arthroplasty (Howmedica, Rutherford, NJ) were analyzed. Survival analysis revealed a best-case 10-year implant survival of 90%. Concurrently, this group of patients exhibited a significant and sustained improvement in Knee Society Score and pain relief after implantation of a rotating hinge component. There were 10 deaths due to unrelated causes during the study period. This constrained hinged prosthesis remains a viable option in the face of gross deformity, bone loss, and failed multiple previous surgical procedures.     

Preserved vision without growth retardation after laparoscopic Roux-en-Y gastric bypass in a morbidly obese child with pseudotumor cerebri: 36-month follow-up

A 12-year-old boy presented with a weight of 136 kg and a history of progressive vision loss associated with unremitting pseudotumor cerebri requiring bilateral optic nerve sheath decompression. He underwent laparoscopic Roux-en-Y gastric bypass (RYGBP) without complication. At 36 months post-RYGBP, he has grown 5 cm since the time of surgery, his weight is 6.8 kg above his postoperative nadir weight of 68.2 kg, and his visual acuity has improved with OD 20/100 (preoperative, 20/200) and OS 20/70 (preoperative, 20/100). This case suggests that RYGBP can be performed safely and without stopping linear growth in carefully selected children.     

Nonunion of the clavicle treated with plate fixation: a review of forty-seven consecutive cases

Forty-seven consecutive patients underwent superior plating for clavicular nonunion between 1995 and 2005. This retrospective analysis was performed to assess the efficacy of plate fixation and the need for iliac crest bone grafting. Forty-three patients were treated with pelvic reconstruction plates and four with straight dynamic compression plates. Of the patients, 30 were treated with local bone graft only, 14 with demineralized bone matrix, and 3 with distant autogenous bone graft. Of the fractures, 93% united after a single operation. Of the patients, 69% returned the Disabilities of the Arm, Shoulder and Hand questionnaire. The mean Disabilities of the Arm, Shoulder and Hand score was 14.6 (range, 0-53). Plate prominence or sensitivity resulted in removal in 20% of cases. We believe that superiorly applied plate fixation is effective for the treatment of clavicular nonunion. Distant autogenous bone graft is not necessary in most cases to obtain union.