Peter J. Brooks

Tibial component fixation in deficient tibial bone stock.

A stylized wedge-shaped defect was created in the medial plateau of autopsy specimens of the tibia to evaluate methods for fixation in total knee arthroplasty. A series of tibial components was inserted by five different methods. With each method loading of up to 1780 N axially and a varus load of 1340 N at 28 Newton-meters were assessed. The vertical deflections of the medial and lateral sides of the tray relative to the bone were measured while bending of the stem was recorded with strain gauges. The greatest deflections occurred when cement alone filled the defect; only slight improvement resulted from the addition of two cancellous screws to buttress the metal tray. Further improvement occurred when solid spacers of Plexiglas or metal were used. Finally, the most secure support was obtained with an integral custom-made tibial component. A central stem 70 mm long carried 23%–38% of the axial load, considered useful in the situation of deficient proximal bone. A metal wedge was considered an acceptable alternative to a custom-made component and may prove useful in the reconstruction of tibial bone stock defects.

The Learning Curve for Adopting Hip Resurfacing Among Hip Specialists

Patient demand and surgeon interest in hip resurfacing has recently increased, but surgeons in the United States are relatively inexperienced with this procedure. We determined the learning curve associated with hip resurfacing and compared the rate of early complications of the first 650 hip resurfacings between five experienced hip surgeons and a national safety survey database study we previously published, which included 89 surgeons and 537 hip resurfacings. Patient demographics and adverse events were recorded. Specific features on pre- and postoperative radiographs were measured in a blinded fashion by a single observer. There were 13 major complications (2.0%), which is 3.7 times lower than our national safety survey complication rate of 7.4%. All fractures occurred in the first 25 cases performed. The complication rate was higher for the first 25 procedures (5.6%) compared with the second 25 procedures (1.6%). For experienced hip surgeons, the learning curve for avoiding early complications was short, 25 cases or less. The learning curve for achieving the desired component positioning radiographically was much longer, 75 to 100 cases or more. If achieving some ideal component position proves important for long-term function and implant survival, improved instrumentation and surgical techniques would be necessary to shorten the learning curve.Level of Evidence: Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Continuous femoral nerve analgesia after unilateral total knee arthroplasty: stimulating versus nonstimulating catheters.

BACKGROUND:Continuous femoral analgesia provides extended pain relief and improved functional recovery for total knee arthroplasty (TKA). Stimulating catheters may allow more accurate placement of catheters. METHODS:We performed a randomized prospective study to investigate the use of stimulating catheters versus nonstimulating catheters in 41 patients undergoing TKA. All patients received IV patient-controlled anesthesia for supplementary pain relief. The principal aim of the trial was to examine whether a stimulating catheter allowed the use of lesser amounts of local anesthetics than a nonstimulating catheter. The additional variables we examined included postoperative pain scores, opioid use, side effects, and acute functional orthopedic outcomes. RESULTS:Analgesia was satisfactory in both groups, but there were no statistically significant differences in the amount of ropivacaine administered; the median amount of ropivacaine given to patients in the stimulating catheter group was 8.2 mL/h vs 8.8 mL/h for patients with nonstimulating catheters, P = 0.26 (median difference −0.6; 95% confidence interval, −2.3 to 0.6). No significant differences between the treatment groups were noted for the amount of fentanyl dispensed by the IV patient-controlled anesthesia, numeric pain rating scale scores, acute functional orthopedic outcomes, side effects, or amounts of oral opioids consumed. CONCLUSION:The use of stimulating catheters in continuous femoral nerve blocks for TKA does not offer significant benefits over traditional nonstimulating catheters.

Incidence and Location of Pain in Young, Active Patients Following Hip Arthroplasty

Persistent pain following hip arthroplasty remains a concern, especially in young, active patients. Four hundred twenty patients less than 60 years of age with a pre-symptomatic UCLA score ≥ 6 (196 total hip arthroplasty [THA]; 224 surface replacement arthroplasty [SRA]) completed a pain-drawing questionnaire investigating the location, severity, and frequency of pain around the hip. At a mean of 2.9 years of follow-up, 40% reported pain in at least one location around the hip. There was no difference in the incidence of groin pain between SRA and THA patients (32% vs. 29%, P=0.6), but THA patients had a greater incidence of anterior (25% vs. 8%, P<0.001) and lateral (20% vs. 10%, P=0.01) thigh pain. A high percentage of young, active patients experience persistent pain following hip arthroplasty.

Design, Implementation, and Comparison of Methods for Collecting Implant Registry Data at Different Hospital Types

Practical issues surrounding the official establishment of a national arthroplasty registry in the United States remain. The purpose of this study was to compare compliance and accuracy rates associated with 3 methods for voluntarily collecting implant registry data at 3 different hospital types. Methods examined included (1) scannable paper forms, (2) online forms comprising keypunching for implant data input, and (3) the same electronic form but incorporating barcode scanning for implant data entry. Overall compliance was low (930/1761; 52.8%) and decreased with each successive data collection phase. Total accuracy rate was 62.5% (578/925) and varied significantly among sites (P < .001). Even with relatively simple reporting systems, compliance was poor. This emphasizes the need for direct surgeon involvement, strict oversight, and a feedback system to ensure validity, particularly if a volunteer-based system is used.

Late Infections of the Foot Due to Incomplete Removal of Foreign Bodies: A Report of Two Cases

Foreign bodies in the foot can remain silent for years before presentation. We describe two foreign body infections in the feet of two patients more than 18 years after the initial insult. These cases emphasize the need for careful evaluation of patients with an unexplained infection in the foot, and thorough debridement, when surgical treatment is necessary.

Radiographic parameters associated with pain following total hip and surface arthroplasty.

Pain following total hip arthroplasty (THA) and surface arthroplasty (SRA) remains a significant source of patient dissatisfaction. Two hundred twenty-four SRA and 196 THA patients completed a pain drawing questionnaire and postoperative radiographic measurements of component positioning were performed. In the SRA cohort, 11 of 21 patients (52%) with acetabular uncoverage of ≥5 mm versus 43 of 147 (29%) with acetabular uncoverage of ≤4.9 mm reported groin pain (P=.03). In the THA cohort, an increased distal-third canal fill ratio and a lower canal calcar ratio trended towards a higher incidence of thigh pain (P=.10 and .06), while a decreased mid-third canal fill ratio was associated with increased severity of thigh pain (P=.04). This study identifies associations between radiographic findings and pain following THA and SRA.

Short-term Results of Birmingham Hip Resurfacing in the United States

Previous data on the survivorship of the Birmingham Hip Resurfacing (BHR) implant have come from design surgeons and large national databases outside of the United States, and there is a lack of reported outcomes of surface replacement arthroplasty from US centers. A retrospective study was undertaken of 1271 hips treated with a BHR system (Smith & Nephew, Memphis, Tennessee) between June 2006 and September 2008 at 6 high-volume total joint centers in the United States. Demographic features, Harris Hip Score (HHS), and radiographic findings were recorded. Patients who did not have a 2-year follow-up visit were contacted by telephone. All patients were asked about complications, reoperations, or failure of the implants. Of the treated hips, 1144 (90%) had a minimum of 2 years of clinical follow-up (mean, 2.9 years; range, 1.8-4.2 years). Mean age was 52.3 years, and 75% of patients were men. Mean HHS improved from 55.8 preoperatively to 97.4 at the most recent follow-up (P<.001). There were 16 (1.4%) revisions to total hip arthroplasty (THA) for fracture (7), early dislocation (3), acetabular component malpositioning with pain (3; 1 with metallosis), infection (1), femoral loosening (1), and pseudotumor (1). There were 9 additional complications (0.8%) that did not require revision, including 3 dislocations treated with closed reduction, 2 fractures, 3 nerve injuries, and 1 pseudotumor. At 2 to 4 years of follow-up, the revision rate and the major complication rate with the BHR system were similar to those in previous reports of primary THA. Excellent clinical results were observed, but further follow-up is necessary to assess mid- and long-term results with the BHR system in US patients.

Surgical hip dislocation through a direct lateral approach: A cadaveric study of vascular danger zones

OBJECTIVE There is limited information on the potential danger to the vascularity of the femoral head during surgical dislocation of the hip using the direct lateral approach. The objective of this study was to investigate the topographical anatomy of the medial femoral circumflex artery (MFCA), the primary source of blood supply to the femoral head, in relationship to the direct lateral approach. METHODS Seven unembalmed cadaver hips had dye injection into either the profunda femoris artery or the MFCA. Surgical hip dislocation was then performed through a direct lateral approach, noting the danger zones to the MFCA branches during each step of the exposure. RESULTS None of the MFCA branches were found to cross the anterior surgical field superficial to the capsule. The deep (main) branch of the MFCA pierced the inferior capsule at the level of the lesser trochanter after emerging posterior to iliopsoas tendon. Ascending branches up the medial femoral neck were identified at this level. The deep branch then coursed posteriorly terminating in a variable number of vessels ascending the posterior femoral neck. Dislocation of the femoral head did not stretch or alter the course of the deep branch of the MFCA. CONCLUSION Safe surgical hip dislocation preserving the MFCA can be performed though a direct lateral approach as long as the inferomedial portion of the anterior capsule is preserved (main branch of the MFCA pierces the capsule at this level). Extracapsular injury is possible from inadvertent dissection at the level of the lesser trochanter or aggressive retraction on the iliopsoas. The posterior capsule should be left intact and instrumentation around the posterior neck should be avoided.

Birmingham Hip Resurfacing in Patients 55 Years or Younger: Risk Factors for Poor Midterm Outcomes

BACKGROUND Birmingham hip resurfacing (BHR) is the only Food and Drug Administration-approved hip resurfacing system available in the United States and is used as an alternative to conventional total hip arthroplasty in younger patients. The purpose of this study is to report on the midterm outcomes of BHR in patients 55 years and younger, and specifically to examine the risk factors for aseptic failure, all-cause revision, and complications in this patient population. METHODS Four hundred forty-two consecutive patients with 5-year follow-up were retrospectively reviewed. Multivariate analyses were conducted to control for potential confounding factors identified by univariate analyses. RESULTS Mean follow-up was 71.68 ± 10.24 months. Among the potential risk factors, only female gender and smaller head sizes had a significant univariate relationship with aseptic revision, all-cause revision, and all-cause complications. When both risk factors were included in a multivariable logistic regression model, analyses showed both variables were closely related, with female gender a better predictor of adverse outcomes than head size (ie, small head size can be thought of as a proxy for female gender). The 5-year implant survival is 95.1% females compared to 99.0% in males. CONCLUSION Hip resurfacing with BHR has excellent survival rates in young patients with degenerative hip disease. Although this study suggests that females with small templated head sizes may not be suitable candidates for BHR, further studies are needed to better understand the underlying differences in gender.