Jason M. Hurst

Complications of clavicle fractures treated with intramedullary fixation

HYPOTHESIS Recent studies have demonstrated better outcomes with operative fixation of displaced midshaft clavicle fractures. We hypothesize that the risk of major complication with intramedullary fixation for clavicle fractures will be low. MATERIALS AND METHODS Clavicle fractures in 58 patients were treated with intramedullary fixation. Patients were excluded for concomitant pathologies and prior surgery status. Data collected included age, gender, treatment, fracture location, time of pin removal, type of complication, dates of further surgery, and American Shoulder and Elbow Surgeons (ASES) score. Complications were grouped into major (infection, nonunion, malunion) and minor (skin erosion, painful hardware, hardware breakage without consequence) categories. The mean age at surgery was 38 years (range, 18-67 years). All pins were removed at an average of 67 days (95% confidence interval, 54-85). RESULTS Of the 58 patients, 15 (25.8%) complications occurred in 14 patients (24.1%). Five (8.6%) were classified as major (5 nonunions requiring revision surgery). Ten (17.2%) were classified as minor (1 delayed union, 2 superficial wound infections, 2 hardware failures after union, 5 skin erosions with pin exposure but without significant infection). Postoperative ASES scores average 89 at a mean follow-up of 7 years. DISCUSSION Complete union and function were achieved in most patients, with an 8.6% risk of major complication. Intramedullary fixation has the potential for early but temporary hardware prominence, hardware exposure, and a slightly higher incidence of nonunion. CONCLUSION Patients with intramedullary fixation can expect smaller scars, no long-term hardware complications, and small potential for refracture or further hardware-related complications after hardware removal.

Does preoperative patellofemoral joint state affect medial unicompartmental arthroplasty survival

One contested contraindication to medial unicompartmental knee arthroplasty (UKA) has been status of the patellofemoral joint. Surgeons have avoided UKA when the patellofemoral joint has radiographic evidence of arthritic changes. However, recent studies advocate ignoring patellofemoral joint status when considering UKA. The purpose of this study was to compare the failure rate of mobile-bearing, medial UKA in patients with and without preoperative radiographic evidence of patellofemoral joint degeneration. Preoperative radiographs from a random selection of 503 patients (638 knees) treated with UKA for anteromedial osteoarthritis were assessed by an observer blinded to clinical outcome. The patellofemoral joint was graded using the modified Altman classification from 0 to 3 with 0 being no evidence of changes and 3 being severe, and identified 396 grade 0, 168 grade 1, 65 grade 2, and 9 grade 3 knees. At 1- to 7-year follow-up, there have been 17 revisions for overall survivorship of 97.3%. Kaplan-Meier analysis predicted 97.9% survival in knees with patellofemoral joint disease and 93.8% survival in knees without patellofemoral joint disease at 70 months (P=.1). Failure requiring revision occurred in 3.5% (14/396) of grade 0 knees, 1.2% (2/168) of grade 1, 1.5% (1/65) of grade 2, and 0% (0/9) of grade 3. No survival difference was noted between knees with medial or lateral patellofemoral joint disease (P=.1). No knees were revised for progression of disease in the patellofemoral joint or anterior knee pain. In light of this investigation and the work of others, preoperative radiographic changes in the patellofemoral joint can be safely ignored when considering patients for medial UKA without compromising survivorship.

Radiographic Comparison of Mobile-Bearing Partial Knee Single-Peg Versus Twin-Peg Design

The femoral component and proprietary instrumentation of a mobile-bearing unicompartmental knee arthroplasty (UKA) was redesigned with an additional peg for enhanced fixation, 15° of extra femoral surface for contact in deep flexion, more rounded profile, better fit into the milled surface, and redesigned intramedullary based instrumentation. To assess the benefit of these changes, we compared postoperative radiographs of 219 single-peg and 186 twin-peg UKAs done in 2008-2011. All surviving knees demonstrated satisfactory position and alignment with no radiolucencies observed. Radiographic analysis showed improved and consistent component positioning with the twin-peg design implanted with updated instrumentation compared with the single-peg. The radiographic benefits of improved implant positioning using the twin-peg component and updated instrumentation are clear and carry tremendous potential. More robust follow-up is imperative.

Abnormal Preoperative MRI Does Not Correlate with Failure of UKA

Modern indications for medial mobile-bearing unicompartmental knee arthroplasty (UKA) include a normal lateral compartment, minimal patellofemoral disease, and a ligamentously stable knee. Radiographs and intraoperative inspection can determine the appropriateness of UKA. Magnetic resonance imaging (MRI) interpretations can over-estimate the degree of knee pathology. This study reports the outcomes of UKA performed despite an abnormal MRI of the lateral compartment, patellofemoral compartment, and/or cruciate ligaments. One thousand consecutive medial UKAs were reviewed, and 33 patients had pre-operative MRI with interpretations of osteoarthritic changes in the lateral compartment, patellofemoral compartment, and/or deficiency of the anterior cruciate ligament (ACL). We compared the postoperative Knee Society pain score, total score, and functional score between the abnormal MRI group (n=33) and the remaining patients (n=967). Average follow-up was 43.4months and 38.3months for the two groups, respectively. Knee Society pain, total, and functional scores for the abnormal MRI group were 40.8, 88.7, and 78.5 respectively compared with 43.4, 90.6, and 80.0 respectively for the remaining patients. The failure rate was 3% (1/33) in the abnormal MRI group and 4% (39/967) in the remaining patients. Based on the numbers available, there were no differences between the two groups in terms of survival and clinical results. The results of this study suggest abnormal preoperative MRI findings do not have an influence on the outcome of UKA when modern radiographic and clinical criteria are met.

Mobile-bearing Unicondylar Knee Arthroplasty: The Oxford Experience

With the recent increase in medial unicompartmental arthroplasty, this article reviews the design history, indications, results, and modern technique for the implantation of the Oxford mobile-bearing unicompartmental arthroplasty. The article also discusses how the indications for the Oxford differ from the historical indications for medial unicompartmental arthroplasty and supports this paradigm shift with review of the recent data. A detailed series of surgical pearls is also presented to help surgeons with the surgical nuances of the Oxford partial knee.

A Simple and Reliable Technique for Placing the Femoral Neck Guide Pin in Hip Resurfacing Arthroplasty

Early failure of hip resurfacing has been attributed to component malposition and other factors. Accurate placement of the femoral guide pin is challenging with commercial guides, and computer navigation adds considerable cost to the procedure. Precise pin placement can be achieved by drilling a 2.8-mm pin across the hip joint in a retrograde fashion similar to placing a dynamic hip screw pin. After hip exposure and dislocation, the femoral guide pin can be advanced using the predrilled tract and then used for femoral head preparation.