Assessment of painful total shoulder arthroplasty using computed tomography arthrography.

BACKGROUND: This study assessed the accuracy of computed tomography (CT) arthrography when evaluating glenoid component stability in the setting of postarthroplasty shoulder pain. METHODS: We retrospectively reviewed all patients presenting to the clinic during a 5.5-year period to identify those with a painful shoulder arthroplasty more than 1 year after the index procedure. We excluded reverse and hemiarthroplasty procedures, patients with a clearly identifiable cause for pain, such as rotator cuff insufficiency or gross component loosening as seen on plain radiographs, and those with culture-positive aspiration. There were 14 patients with suspected glenoid component loosening but inconclusive plain radiographs. Each of the 14 patients underwent a CT arthrogram that was evaluated by the senior author (J.J.P.W.) for the presence or absence of contrast material underneath the polyethylene component. Operative reports and surgical videos from subsequent arthroscopy were reviewed to assess glenoid component stability as determined by direct arthroscopic visualization. RESULTS: CT arthrography suggested glenoid component loosening in 8 of 14 patients (57.1%), and arthroscopic inspection identified loosening in 10 of 14 patients (71.4%). In 3 of 10 patients (30%), CTA suggested a well-fixed glenoid component, but gross loosening was identified during arthroscopy. In this study, CTA yielded a sensitivity of 70%, a specificity of 75%, a positive predictive value of 87.5%, and a negative predictive value of 50.0%. CONCLUSION: CTA had a low negative predictive value (50%), and therefore, the prediction of component stability based on the absence of contrast between the glenoid component and the bone-cement interface does not always reflect true stability.

Catastrophic polyethylene failure diagnosed with magnetic resonance imaging in a painful total knee arthroplasty.

Determining the etiology of a painful knee after arthroplasty can be extremely challenging. Traditionally, orthopedists relied mainly on physical examination, laboratory results, serial radiographs, and 3-phase bone or indium-labeled white blood cell scans; however, recent advances in magnetic resonance imaging (MRI) software have given orthopedists another powerful tool in their diagnostic armamentarium. We provide the MRI software modification technique for metallic artifact reduction as well as present a novel case in which MRI was used to diagnose catastrophic polyethylene postfailure in a posterior cruciate ligament substituting knee. Although the role for MRI in the postarthroplasty knee has yet to be clearly defined, its utility in working up a painful arthroplasty when history, physical examination, and other diagnostic utilities fail to provide answers is clearly demonstrated in this case.

Use of the Gartland classification system for treatment of pediatric supracondylar humerus fractures.

The extension-type pediatric supracondylar humerus fracture accounts for nearly two-thirds of all pediatric hospitalizations due to elbow trauma. The Gartland classification guides the standard of care for treatment of this entity. Type I injuries are treated with cast immobilization while type II and III injuries are treated operatively. The reported interobserver reliability ranges from moderate to full agreement, which is on par with other frequently referenced classification systems such as Lauge-Hansen for adult ankle fractures. In this study, 4 fellowship-trained pediatric orthopedic surgeons reviewed radiographs of 72 pediatric supracondylar fractures and classified them based on Gartland's system. They recommended their preferred treatment of cast immobilization for type I fractures and of closed reduction and pinning in the operating room for type II and type III fractures. The interobserver and intraobserver reliability for each set of radiographs was then analyzed. There was moderate agreement comparing all fractures and comparing types I and II fractures, while there was full agreement for type III fractures. There was full agreement for the intraobserver reliability. The preferred treatment (casting vs operative intervention) differed in 35% of patients, if based on the fracture classification.

Posterior thigh compartment syndrome as a result of a basketball injury.

Acute compartment syndrome of the thigh is a serious although rare occurrence that was sparsely documented in the orthopedic literature until Schwartz et al reported on a series of 21 cases. Although classically associated with high-energy femur fracture, thigh contusion, or the use of military anti-shock trousers, compartment syndrome of the thigh has recently been diagnosed in seemingly low-energy injuries. A complete hamstring avulsion from its ischial origin during routine ambulation and rupture of the quadriceps tendon after a low-energy fall have been shown to result in compartment syndrome. In light of the potential medicolegal ramifications surrounding the diagnosis of compartment syndrome, emergency room consultations to rule out compartment syndrome are on the rise. Specifically, the time to fasciotomy was found to be linearly related to indemnity payment, and a fasciotomy performed within 8 hours was uniformly associated with a successful defense. This article describes a case of a 29-year-old healthy man who developed posterior thigh compartment syndrome as a result of an intrasubstance tear of the biceps femoris muscle sustained while attempting a lay-up during a recreational basketball game. His posterior thigh compartment pressure measured 70 mm Hg and he required emergent posterior thigh compartment fasciotomy.

Minimally invasive A2 flexor tendon pulley and biomechanical comparison with two accepted techniques.

The increasing popularity of rock climbing and its associated injury of closed traumatic pulley A2 rupture has sparked investigator interest in pulley biomechanics. Biomechanically, the A2 and A4 pulleys are important for preventing bowstringing of the flexor tendon upon digital flexion. The literature is replete with reparative techniques for A2 pulley rupture. These techniques include direct fibrous tissue repair, as well as the use of palmaris longus autograft for single- and double-loop reconstruction. Through a previously undescribed minimally invasive double-anchor technique, we used palmaris longus tendon and 2-mm bioabsorbable suture anchors to reconstruct the A2 pulley at its anatomical location in a cadaver model. Then the ultimate load to failure of this reconstruction was tested against 2 known reconstructive techniques, namely, single-loop and double-loop palmaris repair. There was no significant difference between the strength of the previously described single-loop technique and our novel double-anchor technique. Furthermore, our minimally invasive repair obviated the need for the circumferential dissection and soft tissue trauma associated with the single- and double-loop repairs.

A2 and A4 flexor pulley biomechanical analysis: comparison among gender and digit.

Rock climbing has become increasingly more popular in the USA over the past two decades. Accordingly, with increased participation comes an increase in climbing-related injuries. Rooks et al noted that three-quarters of elite and recreational climbers will suffer upper extremity injuries, approximately 60% involving the hand or wrist and 40% divided evenly between the shoulder and elbow. Most of these injures will be strains, microtrauma, and tendonitis; however, 30-50% represent trauma to the proximal interphalangeal region. The purpose of this study was to investigate the biomechanical properties of the A2 and A4 pulley and compare biomechanical properties among gender and digit. A specially designed materials testing machine, shown in the included figure, measured maximum breaking load, displacement and stiffness of the A2 and A4 pulleys of ten cadaveric hands using an S hook to apply a steady force until complete pulley rupture. The A2 and A4 biomechanical properties of breaking load, displacement, and stiffness did not significantly differ among the index, middle, ring, and little fingers. Additionally, there was no significant difference in A2 or A4 pulley biomechanics between male and female specimens. The A2 and A4 pulleys among differing digits and genders have similar biomechanical properties in regards to maximum breaking load, displacement, and stiffness.

Recurrent instability after total hip arthroplasty: beware of subtle component malpositioning.

Most patients exhibiting instability after total hip arthroplasty can be treated nonoperatively. However, instability may become recurrent and require surgical intervention. Abductor insufficiency and component malpositioning constitute two of the most important causes of recurrent instability, although the exact cause may not be identifiable in some patients. There is relative scarcity of reports in the literature regarding the outcome of surgical intervention for recurrent instability; however, it is known that surgical intervention is likely to have a better outcome in patients for whom the cause of recurrent instability can be identified. We hypothesized that component malpositioning, which may be subtle in some cases, is the cause of recurrent instability for many patients. The outcomes of revision arthroplasty in 93 patients who were treated at our institution for recurrent instability were reviewed. Component malpositioning was found to be the major cause of recurrent instability in this successfully treated cohort.

Percutaneous release of A1 pulley.

We performed 100 percutaneous releases of the trigger digits in a cadaveric model using an 18-gauge needle. Successful percutaneous release was achieved for only 59 digits (59%). No neurovascular injury occurred. We found that a percutaneous trigger digit release resulted in high percentage of incomplete releases of A1 pulley, especially in the thumb, index, and little fingers.