Guiding Device for the Patellar Cut in Total Knee Arthroplasty: Design and Validation.

An incorrect cut of the patella (kneecap) during total knee arthroplasty, affects the thickness in different quadrants of the patella, leading to pain and poor function. Because of the disadvantages of existing devices, many surgeons choose to perform the cut freehand. Given this mistrust of existing devices, a quick, but accurate, method is needed that guides the cut, without constraining the surgeon. A novel device is described that allows the surgeon to mark a line at the desired cutting plane parallel to the front (anterior) surface using a cautery tool, remove the device, and then align the saw guide, reamer, or freehand saw with the marked line to cut the patella. The device was tested on 36 artificial patellae, custom-molded from two shapes considered easier and harder to resect accurately, and eight paired cadaveric specimens, each in comparison to the conventional saw guide technique. The mediolateral angle, superoinferior angle, difference from intended thickness, and time were comparable or better for the new device. Addressing the remaining outliers should be possible through additional design changes. Use of this guidance device has the potential to improve patellar resection accuracy, as well as provide training to residents and a double-check and feedback tool for expert surgeons.

The incidence of proximal deep vein thrombosis after elective hip arthroscopy: a prospective cohort study in low risk patients.

Prospectively assess the incidence of deep venous thrombosis (DVT) using Doppler Ultrasound, in patients receiving elective hip arthroscopy without pharmacologic/mechanical prophylaxis. One hundred and fifteen consecutive patients (mean 35.4 years, SD = 10.3) underwent elective hip arthroscopy. Patients with previous major risk factors for DVT were excluded. Signs/symptoms of DVT/pulmonary embolism were assessed at 2-week post-operatively. A bilateral whole leg Duplex color (Doppler) Ultrasonography was scheduled between 10- and 22-day post-op. The primary outcome was frequency of DVT. Secondary outcomes assessed surgical risk factors. One hundred and ten patients (mean = 34.3 years, SD = 10.1) did not get a DVT. Five patients (mean = 43.8 years, SD = 12.1) were diagnosed with a DVT, 2- to 22-day post-operatively. All DVT patients received arthroscopy in the supine position (n = 76), versus no patients in the lateral position (n = 39). Average traction time was 38 (SD = 4) and 61 (SD = 4) minutes for patients with and without a DVT, respectively. All other a priori defined risk factors were similar. Four out of five patients presented with symptoms of a DVT, confirmed by ultrasound. One patient was without symptoms/clinical findings. Four patients had a DVT restricted to the calf veins; one patient had involvement of the popliteal vein. No patients had proximal extension into the thigh or pelvis. No pulmonary emboli were suspected or occurred. The incidence of deep venous thromboembolism is 4.3%. The majority of patients had symptomatic and distal venous thromboembolic events. This study provides supportive evidence that routine prophylaxis and/or screening may not be necessary in low risk patients undergoing elective hip arthroscopy.

Locking plate fixation provides superior fixation of humerus split type greater tuberosity fractures than tension bands and double row suture bridges.

BACKGROUND: This paper aims to determine the strongest fixation method for split type greater tuberosity fractures of the proximal humerus by testing and comparing three fixation methods: a tension band with No. 2 wire suture, a double-row suture bridge with suture anchors, and a manually contoured calcaneal locking plate. METHODS: Each method was tested on eight porcine humeri. A osteotomy of the greater tuberosity was performed 50° to the humeral shaft and then fixed according to one of three methods. The humeri were then placed in a testing apparatus and tension was applied along the supraspinatus tendon using a thermoelectric cooling clamp. The load required to produce 3mm and 5mm of displacement, as well as complete failure, was recorded using an axial load cell. FINDINGS: The average load required to produce 3mm and 5mm of displacement was 658N and 1112N for the locking plate, 199N and 247N for the double row, and 75N and 105N for the tension band. The difference between the three groups was significant (P<0.01). The average load to failure of the locking plate (810N) was significantly stronger than double row (456N) and tension band (279N) (P<0.05). The stiffness of the locking plate (404N/mm) was significantly greater than double row (71N/mm) and tension band (33N/mm) (P<0.01). INTERPRETATION: Locking plate fixation provides the strongest and stiffest biomechanical fixation for split type greater tuberosity fractures.

The Impact of Superior Labral Anterior to Posterior Lesions on Functional Status in Shoulder Instability: A Multicenter Cohort Study.

BACKGROUND: Type IV superior labral anterior to posterior (SLAP) lesions, which are superior labral detachments associated with Bankart tears, are reported to occur in up to 25% of recurrent shoulder instability patients. However, the clinical implications of this finding are debatable. PURPOSE: To determine whether there are any functional differences between anterior instability patients with and without type IV SLAP lesions at the time of presentation and at short-term follow-up after surgical intervention. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: A prospective, multicenter database was established to follow the clinical evolution of patients with shoulder instability. Patients were diagnosed as having a type IV SLAP lesion at the time of arthroscopic Bankart surgery (SLAP+). These patients were compared with a group of patients who simply had a Bankart lesion (SLAP-). The 2 groups had their functional outcomes (Western Ontario Shoulder Instability Index [WOSI]; Disability of the Arm, Shoulder, and Hand [QuickDASH]; and Walch-Duplay) compared prior to surgery and 1 year postoperatively. RESULTS: A total of 103 subjects were included in the study; of these, 56 (43 men, 13 women) completed 1-year follow-up. Twenty-three subjects had a type IV SLAP tear, and most had this repaired along with their Bankart lesion. At baseline, SLAP+ subjects had inferior QuickDASH scores compared with SLAP- subjects (37.8 vs 29.0) as well as poorer pain subscores on both the WOSI and QuickDASH. At 1-year follow-up, however, there were no significant differences in any of the outcome measures. CONCLUSION: A type IV SLAP lesion can be expected in 22% of patients with recurrent shoulder instability. This finding implies that at baseline, the patient will have slightly worse functional scores related to pain. However, following surgical management of the labral pathology, these patients will have equivalent functional outcomes at short-term follow-up. CLINICAL RELEVANCE: With surgical management of the superior and anteroinferior labrum, patients with type IV SLAP lesions will do as well as those with only Bankart tears. Thus, the presence of SLAP lesions should not alter the decision to provide surgical management and should not change the prognosis for a specific patient.

Successful treatment of fractures of the base of the acromion after reverse shoulder arthroplasty: Case report and review of the literature.

Fractures of the acromion and scapula are known to occur after reverse shoulder arthroplasty. We present a case of a fracture at the base of the acromion 5 months after arthroplasty treated successfully with dual plating of the acromion. Eighteen months after fracture fixation, the patient had 160 degrees of active forward flexion, a QuickDASH of 29.5, a Constant score of 69 and she was satisfied with the result. A concomitant review of the literature produced, in addition to our patient, 56 cases. These were used to produce a classification system, based on bony and functional anatomy as follows. Tip fractures are of the most lateral or anterior portion of the acromion, those of the body of the acromion are medial to the tip but lateral to the beginning of the scapular base. Fractures at the scapular base are termed fractures of the base of the acromion and those more medial to that, fractures of the scapular spine. The functional results of these case series demonstrated poorer functional outcomes for more medial fractures. As future research in this domain increases, clarity on the nomenclature of these fractures will allow for prognostication and treatment based on fracture location as well as comparison between studies.

Obesity and early reoperation rate after elective lumbar spine surgery: a population-based study.

STUDY DESIGN: Population-based retrospective cohort study. CLINICAL QUESTION: Are patients with a body mass index (BMI) of 35 or more who undergo elective lumbar spine surgery at increased risk of post-surgical complications, as evidenced by reoperation within a 3-month period? METHODS: The Alberta Health and Wellness Administrative database was queried to identify patients who underwent elective lumbar spine surgery over a 24-month period. This same database was used to classify subjects as obese (BMI ≥35) and non-obese (BMI <35) and to determine who underwent repeated surgical intervention. The rate of reoperation was determined for both the obese and non-obese groups; further analyses were performed to determine whether certain subjects were at increased risk of reoperation. RESULTS: The point estimate for relative risk for requiring reoperation was 1.73 (95% confidence interval, 1.03-2.90) for obese subjects compared with non-obese subjects. The adjusted point estimate shows that deformity correction surgery is predictive for early reoperation while obesity is not. CONCLUSIONS: In obese subjects we observed an increased complication rate after elective lumbar spine surgery, as evidenced by reoperation rates within 3 months. When we considered other possible associations with reoperation, in adjusted analysis, deformity surgery was found to be predictive of early reoperation.Final class of evidence-prognosisSTUDY DESIGNProspective CohortRetrospective Cohort•Case controlCase seriesMETHODSPatients at similar point in course of treatment•F/U ≥ 85%•Similarity of treatment protocols for patient groups•Patients followed up long enough for outcomes to occur•Control for extraneous risk factorsOverall class of evidenceIIIThe definiton of the different classes of evidence is available on page 55.