Christopher J. Wahl

Pathomechanisms and complications related to patient positioning and anesthesia during shoulder arthroscopy.

The lateral decubitus and beach-chair positions each offer unique benefits to the shoulder surgeon with respect to visualization, efficiency, and ease during arthroscopic shoulder procedures. The purpose of this article was to comprehensively review the reports and studies documenting independent and dependent complications related to patient positioning and anesthesia during arthroscopic shoulder surgery. The lateral decubitus position has been associated with the potential for peripheral neurapraxia, brachial plexopathy, direct nerve injury, and airway compromise. The beach-chair position has been associated with cervical neurapraxia, pneumothorax, and the potential for end-organ hypoperfusion injuries (when deliberate hypotension is used). Potentially concerning are hypotensive bradycardic events, which may be relatively common in association with the use of epinephrine-containing interscalene anesthetics in beach chair-positioned patients. Irrigant complications (fluid spread, ventricular tachycardia) are avoidable risks not unique to either specific position. Although minor transient anesthetic- and position-related complications (neurapraxia, hypotension) may occur in as many 10% to 30% of patients, major complications such as end-organ damage or permanent impairments are exceedingly rare. Regardless of position, complications are almost uniformly avoidable if surgeon and anesthetist exercise care and prudent attention to position and anesthetic choices. The purpose of this article is to review the potential for position- and anesthesia-related complications and acquaint the shoulder surgeon with the proposed pathophysiologic mechanisms that can lead to them.

Practical management of knee dislocations: a selective angiography protocol to detect limb-threatening vascular injuries.

Knee dislocations are relatively uncommon but potentially catastrophic injuries. In athletes, these injuries generally result from high-energy traumatic mechanisms such as collisions in football and rugby, high-velocity falls in skiing, and falls from heights in gymnastics and extreme sports. Knee dislocations are frequently associated with coincident neurological or vascular injuries. Recognition of vascular injury is particularly challenging because vascular compromise may not be immediately associated with clinical signs of ischemia and may result from injuries without complete or evident dislocation. This article reviews the rationale behind selective angiography, adjunctive vascular testing, and the need for observation after multiligament knee trauma. An algorithm for the diagnosis of vascular injuries is presented.

Arthroscopy of the posterior knee compartments: neurovascular anatomic relationships during arthroscopic transverse capsulotomy.

PURPOSE To clearly define the anatomic relations that exist in the posterior knee under arthroscopic conditions in a cadaveric model and to describe a technique for an all-arthroscopic posterior capsule release. METHODS Seven cadaveric knees were examined under arthroscopic conditions. After a routine diagnostic arthroscopy of the anterior compartment, posteromedial and posterolateral portals were created, the posterior capsule and septum were released, and the distance from the posterior border of the tibial insertion of the posterior cruciate ligament (PCL) to the popliteal artery was measured under direct arthroscopic visualization after capsulotomy. The distances from the posteromedial arthroscopic portal and lateral arthroscopic portal to the saphenous neurovascular bundle and peroneal nerve, respectively, were evaluated. RESULTS The mean distance between the PCL and popliteal artery was 19.3 mm (range, 15 to 28 mm; SD, 4.27 mm); between the posteromedial portal and saphenous vein, 22.6 mm (range, 16 to 35 mm; SD, 6.7 mm); and between the posterolateral portal and peroneal nerve, 40 mm (range, 30 to 52 mm; SD, 7.94 mm). CONCLUSIONS When arthroscopic posterior transverse capsulotomy is performed via the authors technique and with the knee flexed to 90 degrees , there is an adequate safe zone between the popliteal neurovascular structures, peroneal nerve, saphenous neurovascular structures and the posterior capsule, posterolateral and posteromedial portals, respectively (minimum, 15 mm). CLINICAL RELEVANCE With a mean distance of 19.3 mm between the PCL and the popliteal artery after capsulotomy, surgeons can feel confident that a safe zone is present for posterior knee arthroscopy. In addition, they can be reassured that posterior portals are safe if created with the knee in the proper position.

Treatment of posterior cruciate ligament tibial avulsion fractures through a modified open posterior approach: operative technique and 12- to 48-month outcomes.

Objectives: To report clinical and functional outcomes following fixation of tibial posterior cruciate ligament (PCL) avulsion fractures through a modified open posterior approach when combined with a rehabilitation program emphasizing early range of motion. Design: Retrospective case series. Setting: Level I trauma center. Patients: From March 4, 2000 to May 8, 2003, there were 16 cases of PCL tibial avulsion injuries presented to our institution, with 10 patients available for follow up at 12 to 48 months (mean 28 months). Intervention: Fixation of tibial PCL avulsion fractures was with a lag screw and washer placed through a modified open posterior approach. Range of motion was begun on postoperative day 1. Main Outcome Measurements: Clinical stability, range of motion, gastrocnemius muscle strength, radiographic appearance, and each patients overall health-related quality of life (using the musculoskeletal functional assessment tool) were evaluated at final follow up. Results: The average musculoskeletal functional assessment score was 14. (Musculoskeletal functional assessment scores range from 0-100, with higher scores indicating poorer function.) All patients achieved union of their fracture and had clinically stable knees at the latest follow-up. Flexion difference greater than 10 degrees (P = 0.16), extension difference greater than 2 degrees (P = 0.38), and heel raise difference more than 8 repetitions (P = 0.23) were not demonstrated in comparison to the normal side. Conclusions: Treatment of tibial PCL avulsion fractures, which includes fixation through a modified open posterior approach and early postoperative range of motion, results in healing of the fracture, good functional outcomes, stability to posterior draw testing, and does not lead to gastrocnemius weakness or significant range of motion deficits at 12 to 48 months postoperatively.

An Association of Lateral Knee Sagittal Anatomic Factors with Non-Contact ACL Injury: Sex or Geometry?

BACKGROUND Lateral tibiofemoral articular geometry may play a role in the development of non-contact anterior cruciate ligament (ACL) injuries. We hypothesized that athletes who had sustained an ACL injury would demonstrate more highly convex articular surfaces in the lateral compartment of the knee compared with activity-matched athletes who had not sustained an ACL injury, and that women would demonstrate greater absolute and relative convexity of these articular surfaces than men. METHODS One hundred and twelve athletes with a non-contact ACL injury and sixty-one activity-matched athletes without an ACL injury were studied. Three blinded observers measured the articular geometry in the mid-lateral sagittal plane with use of magnetic resonance imaging. The tibial plateau radius of curvature (TPr), distal femoral radius of curvature (Fr), maximal femoral anteroposterior articular length (FAP), and maximal tibial anteroposterior articular length (TPAP) were recorded. The Fr:TPr and FAP:TPAP ratios were also calculated to adjust for size variations. The intraclass correlation coefficient and the two-sample Student t test were used to compare quantitative variables. All data were found to follow a normal distribution. RESULTS When data for male and female patients were combined, the mean TPr, Fr, and TPAP values were significantly smaller in the ACL-injured patients than in the uninjured patients (33.9 compared with 37.5 mm, p = 0.005; 24.3 compared with 25.1 mm, p = 0.04; and 31.5 compared with 33.1 mm, p = 0.007; respectively). The mean FAP value did not differ significantly between the ACL-injured and uninjured patients but the difference in the mean FAP:TPAP value was significant (p = 0.003). When only male patients were analyzed, the mean TPr, Fr, and TPAP values were also significantly smaller in the ACL-injured patients than in the uninjured patients (35.5 compared with 41.1 mm, p = 0.002; 25.5 compared with 26.7 mm, p = 0.001; and 33.0 compared with 35.5 mm, p = 0.0002; respectively). The mean FAP value did not differ significantly between the ACL-injured and uninjured male patients, but the difference in the mean FAP:TPAP value was significant (p = 0.0005). In contrast, when only female patients were analyzed, none of the mean values differed significantly between the ACL-injured and uninjured patients. The FAP:TPAP and Fr:TPr values did not differ significantly among the ACL-injured male patients, injured female patients, and uninjured female patients. CONCLUSIONS All female patients (both ACL-injured and uninjured) and ACL-injured male patients shared a common lateral knee geometry characterized by a smaller tibial plateau length relative to the femur and by more convex articulating surfaces of the proximal aspect of the tibia and the distal aspect of the femur. Shorter, more highly convex articulating surfaces may be inherently less stable with regard to anterior tibial translation and rotation. These findings may partially explain the greater overall predisposition of women compared with men toward ACL injury as well as why some studies have demonstrated no sex differences in graft reinjury after ACL reconstruction.

Initial assessment of the acute and chronic multiple-ligament injured (dislocated) knee.

Multiple-ligament injured knees resulting from knee dislocations are uncommon but serious injuries. These injuries can present to the emergency room acutely or in clinic on a delayed basis, but regardless of the setting they require a complete and detailed assessment to evaluate the extent of the injury. Complicating the diagnosis of a knee dislocation is the fact that acute knee dislocations often spontaneously reduce or are reduced by paramedics in the field before evaluation by a physician. In most cases, pain in the knee, a large knee effusion, and swelling of the effected limb are the only signs and symptoms of a knee dislocation. Quick and accurate assessment of these injuries is required to determine the presence of any limb threatening arterial injuries. In this chapter, we present the complete assessment of acute and chronic multiple ligament knee injuries.

Pronation can increase the pressure on the posterior interosseous nerve under the arcade of Frohse: A possible mechanism of palsy after two-incision repair for distal biceps rupture—Clinical experience and a cadaveric investigation

Posterior interosseous nerve palsy is a recognized complication of 2-incision distal biceps tendon repair. We hypothesize that intraoperative forearm pronation can cause compression of the posterior interosseous nerve beneath the supinator and arcade of Frohse. Six human male cadaver upper extremities were dissected. Pressure on the posterior interosseous nerve beneath the arcade of Frohse and supinator was measured with a Swan-Ganz catheter connected to a pressure transducer. Pressure was significantly elevated in maximal pronation in all specimens with the elbow in both flexion and extension. Pressures at full pronation were significantly higher than pressures measured at 60 degrees of pronation (5 +/- 2 mm Hg in 60 degrees of pronation and 90 degrees of flexion, P < .0001; 7 +/- 3 mm Hg in 60 degrees of pronation and extension, P < 005). Maximal pronation can cause increased pressure on the posterior interosseous nerve. The safety of 2-incision distal biceps repair may be increased by avoiding prolonged, uninterrupted periods of hyperpronation.

Can Magnetic Resonance Imaging Predict Posterior Drawer Laxity at the Time of Surgery in Patients With Knee Dislocation or Multiple-Ligament Knee Injury?

Background: Previous studies indicate that isolated posterior cruciate ligament injuries demonstrate magnetic resonance imaging (MRI) and clinical evidence of healing when treated nonoperatively; however, the authors are unaware of any other study that has looked at whether initial MRI can predict posterior cruciate ligament stability at the time of surgery in patients with knee dislocation. Hypothesis: An MRI grading system will predict laxity on posterior drawer testing at the time of surgery in patients with knee dislocations. Study Design: Cohort study (prognosis); Level of evidence, 2. Methods: Forty-two consecutive patients with knee dislocation or multiple-ligament knee injury evaluated by MRI were included in the study. An assignment of grade 0 (intact), grade I (injured/fibers intact), grade II (partial tearing of ligament), or grade III (complete tear) was made after each reading on 2 separate occasions by 3 surgeons. Posterior laxity of the knee was graded by the magnitude of excursion on the posterior drawer test by the senior author at the time of surgery. Interobserver and intraobserver reliability of the MRI grading scheme expressed by the kappa statistic κ, as well as the predictive value of MRI grade in determining stability of the posterior cruciate ligament at the time of surgery, was assessed. Results: The posterior cruciate ligament injury grading scheme tested demonstrated moderate to substantial intraobserver agreement (κ = 0.66, κ = 0.53, and κ = 0.52, respectively, for all raters). Interobserver reliability demonstrated only moderate agreement (κ = 0.49). If the grading scheme was changed to group both grades 0 and I (intact) and grades II and III (disrupted), intraobserver reliability demonstrated substantial to almost perfect agreement (κ = 0.83, κ = 0.80, and κ = 0.75), and interobserver reliability demonstrated substantial agreement (κ = 0.70). If the posterior cruciate ligament was classified as intact (grade 0 [intact] or grade I [injured]) on initial MRI, the injured knee was judged clinically stable (tibia anterior to or flush with the femoral condyles on posterior drawer testing) at the time of surgery 98.5% (95% confidence interval, 93%-100%) of the time. When the posterior cruciate ligament was classified as disrupted (grade II [partial tear] or grade III [complete tear]), the injured knee was judged unstable (tibia posterior to the femoral condyles on posterior drawer testing) 57.5% (95% confidence interval, 40%-73%) of the time. Conclusion: The presented system of grading posterior cruciate ligament injury in patients with knee dislocation on initial MRI demonstrates moderate to substantial interobserver and intraobserver reliability that increases if the grading scheme is modified. An initial MRI scan read as grade I may predict stability to posterior drawer at the time of surgery. Even with MRI evidence of disruption in the posterior cruciate ligament (grade II and grade III injuries), posterior cruciate ligament reconstruction may not be clinically indicated at the time of reconstruction and/or repair of other associated injuries.

Harvey Cushing as a book collector, bibliophile, and archivist: the precedence for the genesis of the Brain Tumor Registry. Historical vignette.

Influenced by individuals such as his parents, Osler, and Halsted, and by his early medical student experience, Harvey Cushing developed a strong interest in collecting, especially antiquarian medical books. Even today, his collection housed at Yale University is one of the most prestigious in the world. Cushings interest in archives is further manifested and reinforced by his establishment of the Cushing Brain Tumor Registry. The following is a review of Cushings background not as an eminent clinician and surgeon but as an individual best described as a bibliophile, archivist, and ardent collector of medical paraphernalia.

Detached femoral bone plug following anterior cruciate ligament repair

We report the case of a 16-year-old woman who experienced failure of her bone-patellar tendon-bone (BPTB) reconstruction of her left anterior cruciate ligament (ACL) due to detachment of the femoral bone plug from the endobutton. We have only found one prior report of this unusual complication. This case is also notable in that evidence of this complication is visible radiographically. Most postoperative complications of ACL reconstruction can be visualized only with the assistance of magnetic resonance imaging (MRI).