Iliotibial band autograft: what size is the graft? A mathematical and cadaveric model : ITB single and double strand size.

BACKGROUND: The iliotibial band (ITB) is used in anterior cruciate ligament (ACL) reconstruction in skeletally immature patients as well as several other orthopedic reconstructions. The purpose of this study is to determine the size of the ITB as an autograft option in ACL reconstruction surgery or other orthopedic soft tissue reconstructions. METHODS: Five adult cadavers resulting in nine ITB were used. Thickness and width of the ITB were determined. Using ITB width of 15-60 mm, single and doubled graft sizes were determined using standard surgical graft size technique. Geometric calculations based on average graft thickness were used to mathematically confirm the graft size of the ITB. RESULTS: The ITB is less than 1 mm in thickness in males and females. Cadaveric measurements were less than 1 mm larger than mathematical measurements, in majority of measurements. ITB autograft can be harvested to a maximum 9 mm single-stranded graft or > 12 mm doubled graft. A minimum of 50 mm of ITB width is required to make a 8 mm graft. CONCLUSIONS: ITB is a versatile graft that can be used for a graft size up to 9 mm single strand and over 12 mm double strand. A minimum of 50 mm width of ITB is required to obtain a 8 mm-diameter autograft. To ensure appropriate graft size, surgeons should consider harvesting the maximum amount of ITB when performing ACL reconstructions in skeletally immature patients. CLINICAL RELEVANCE: Surgeons have a quick reference for the width of ITB they should harvest based on the size of graft they require for a successful surgery.

Hamstring Autograft Too Small: How Much Allograft Do You Need to Supplement to a Desired Hybrid Graft Size?

PURPOSE: To determine a simple rule for choosing supplemental allograft size for hybrid anterior cruciate ligament reconstruction using mathematical and cadaveric models. METHODS: Mathematical and cadaveric models were used to determine the rule. The mathematical model required application of the geometric Pythagorean theorem to add areas of circles. Cadaveric semitendinosus and gracilis tendons were combined in multiple quadrupled hamstring size combinations and then sized using standard surgical techniques to confirm the mathematical model. RESULTS: Geometric measurement, not simple addition, of graft diameters was required to determine the final graft size. Direct comparison of cadaveric and mathematical models showed close relations. If a final graft size of 7 mm is desired, an added diameter of all grafts of approximately 9.5 mm is needed. If a final graft size of 8 mm is desired, an added diameter of all grafts of approximately 11 mm is needed. If a final graft size of 9 mm is desired, an added diameter of all grafts of approximately 12.5 mm is needed. If a final graft size of 10 mm is desired, an added graft diameter of approximately 14 mm is needed. Cadaveric hamstring measurements were similar to the mathematical model. CONCLUSIONS: By use of mathematical and cadaveric models, simple rules for determining the additional size of allograft diameter needed to supplement undersized hamstring autograft were created. CLINICAL RELEVANCE: With the increasing availability of allograft types and sizes, surgeons currently have no guidelines on the size of allograft that is required to supplement an undersized hamstring autograft. Simple rules were created for determining the amount of allograft supplementation required for undersized hamstrings and are easily applied to clinical situations.

Acetabular component thickness does not affect mid-term clinical results in hip resurfacing.

BACKGROUND: The benefits of using thin acetabular components for hip resurfacing have been shown in terms of bone conservation, but there currently are little data available in the literature addressing the mid-term clinical results of these devices. QUESTIONS/PURPOSES: We aimed to determine whether thinner acetabular components altered mid-term postoperative clinical scores, complication rates, survivorship, radiographic appearance, and metal ion levels. METHODS: Two hundred eighty-one patients with unilateral disease received a 5-mm thick acetabular shell and 223 received a 3.5-mm shell. The femoral component implanted in both groups was identical. We compared clinical scores, complication rates, survivorship, radiographic results, and ion levels between these two groups. RESULTS: UCLA hip scores were similar (pain, p = 0.0976; walking, p = 0.9571; function, p = 0.9316; activity, p = 0.2085). Complications were higher in the 5-mm group (6.4% versus 1.8%, p = 0.0431). Both groups were similar regarding survivorship (p = 0.3181), cup radiolucency at 5 years (p = 0.107), and metal ion levels (cobalt p = 0.404, chromium p = 0.250). CONCLUSIONS: With comparable mid-term clinical results, there is no tangible reason to abstain from using the 3.5-mm acetabular component. LEVEL OF EVIDENCE: Level III, retrospective comparative study. See the Guidelines for Authors for a complete description of levels of evidence.

Wear analysis of 39 conserve plus metal-on-metal hip resurfacing retrievals.

There have been increasing concerns regarding adverse local tissue reactions (ALTR) following metal-on-metal (MOM) hip arthroplasties. This study examined wear rates in retrievals of one design of MOM resurfacing arthroplasty, and assessed the differences in wear between those with and without ALTR. Wear measurements were made on 39 MOM resurfacing components (30 femoral, 9 acetabular) which were at least 2years in vivo. Seven hips (6 patients; 4 acetabular components, 7 femoral components) were identified to have ALTR. Acetabular component abduction and anteversion angles were determined using EBRA, and the contact-patch-to-rim (CPR) distance was calculated. The ALTR group had higher linear femoral and acetabular wear rates, acetabular anteversion and abduction angles, lower CPR, and longer time to revision. Given the increased risk for ALTR associated with acetabular component malpositioning, patients with malpositioned acetabular components may require closer clinical follow-up and monitoring.

Contact patch to rim distance predicts metal ion levels in hip resurfacing.

BACKGROUND: Component design, size, acetabular orientation, patient gender, and activity level have been suggested as factors leading to elevated metal ion concentrations after-on-metal hip resurfacing arthroplasty (MMHRA). The calculation of the contact patch to rim (CPR) distance integrates component size, design, and acetabular orientation and may be a good predictor of elevated metal ion levels. QUESTIONS/PURPOSES: We evaluated the effects and the predictive value of the CPR distance on serum cobalt (CoS) and chromium (CrS) ion levels. METHODS: We retrospectively studied 182 patients with Conserve Plus MMHRAs at a minimum of 12 months after surgery (median, 57 months; range, 12-165 months). CoS and CrS levels were analyzed using inductively-coupled plasma mass spectrometry. Multiple logistic regression was performed to determine which if any of the factors related to serum ion levels. RESULTS: Patients with CPR distances of 10 mm or less had a 37-fold increased risk of having elevated CoS of 7 µg/L or higher. Similarly, these patients had an 11-fold increased risk of having elevated CrS of 7 µg/L or higher. Sex and University of California Los Angeles activity scores did not influence the postoperative CoS and CrS levels. The negative predictive value for CPR distance less than 10 mm was 99.3% for CoS greater than 7 µg/L and 98.0% for CrS greater than 7 µg/L. CONCLUSIONS: Our observations suggest the CPR distance would be a useful indicator to determine which patients are at risk for elevated ion levels. Patients with CPR distances greater than 10 mm need not be monitored unless they become symptomatic.

The insidious risk of periprosthetic fracture in clinically functional total hip arthroplasties: A biomechanical study of willed joints.

Femoral bone quality is a major risk factor of periprosthetic fracture after total hip arthroplasty (THA), which has mortality similar to native hip fractures but higher short-term morbidity. The goal of this study was to quantify cortical strains at the site of expected Vancouver Type-B periprosthetic fracture as a function of bone mineral density, femoral stem material, and fixation method using a series of 29 autopsy-retrieved, clinically asymptomatic hip joints with THA. Periprosthetic bone mineral content and density was assessed using dual-energy X-ray absorptiometry by Gruen Zone. Specimens then underwent combined cyclic axial and torsional loading, increasing incrementally from 100 N and ±1 Nm to peaks of 700 N and ±5 Nm. All specimens experienced significantly higher strains on the lateral surface than on the anterior surface, indicating that the bending loads in the frontal plane, rather than axial/torsional loads, had the predominant effect. Multiple significant relationships (p = 0.04, p = 0.02) were found between predicted periprosthetic strains calculated from radiographic measurements and observed principal strains. Though THA in the present study were in successful clinical service, the produced results indicated that some femurs with rigid cemented or noncemented implants were potentially at high risk for Vancouver Type-B fractures, which may be predicted radiographically.

Histological features of pseudotumor-like tissues from metal-on-metal hips.

BACKGROUND: Pseudotumor-like periprosthetic tissue reactions around metal-on-metal (M-M) hip replacements can cause pain and lead to revision surgery. The cause of these reactions is not well understood but could be due to excessive wear, or metal hypersensitivity or an as-yet unknown cause. The tissue features may help distinguish reactions to high wear from those with suspected metal hypersensitivity. QUESTIONS/PURPOSES: We therefore examined the synovial lining integrity, inflammatory cell infiltrates, tissue organization, necrosis and metal wear particles of pseudotumor-like tissues from M-M hips revised for suspected high wear related and suspected metal hypersensitivity causes. METHODS: Tissue samples from 32 revised hip replacements with pseudotumor-like reactions were studied. A 10-point histological score was used to rank the degree of aseptic lymphocytic vasculitis-associated lesions (ALVAL) by examination of synovial lining integrity, inflammatory cell infiltrates, and tissue organization. Lymphocytes, macrophages, plasma cells, giant cells, necrosis and metal wear particles were semiquantitatively rated. Implant wear was measured with a coordinate measuring machine. The cases were divided into those suspected of having high wear and those suspected of having metal hypersensitivity based on clinical, radiographic and retrieval findings. The Mann-Whitney test was used to compare the histological features in these two groups. RESULTS: The tissues from patients revised for suspected high wear had a lower ALVAL score, fewer lymphocytes, but more macrophages and metal particles than those tissues from hips revised for pain and suspected metal hypersensitivity. The highest ALVAL scores occurred in patients who were revised for pain and suspected metal hypersensitivity. Component wear was lower in that group. CONCLUSIONS: Pseudotumor-like reactions can be caused by high wear, but may also occur around implants with low wear, likely because of a metal hypersensitivity reaction. Histologic features including synovial integrity, inflammatory cell infiltrates, tissue organization, and metal particles may help differentiate these causes. CLINICAL RELEVANCE: Painful hips with periprosthetic masses may be caused by high wear, but if this can be ruled out, metal hypersensitivity should be considered.

Nonarthroplasty Options for the Athlete or Active Individual with Shoulder Osteoarthritis.

The management of glenohumeral osteoarthritis is difficult in young, active individuals. After nonoperative management fails, arthroscopic debridement with concomitant procedures (eg, loose body removal, capsular release, labral debridement, synovectomy, osteophyte resection, bursectomy, subacromial decompression, microfracture, and biceps tenotomy or tenodesis) to address potential pain generators may be an option in small, contained, unipolar lesions.

Highly cross-linked polyethylene in hip resurfacing arthroplasty: long-term follow-up.

Highly cross-linked polyethylene (XLPE) has improved wear properties. This study reports the results of a small series of patients treated over 10 years ago with a metal-on-XLPE hip resurfacing.A total of 21 hips in 20 patients received a hip resurfacing with a cobalt-chromium metal femoral head and metal-backed acetabular cup lined with a XLPE insert and were retrospectively studied. Kaplan-Meier Survivorship was calculated.Five patients who had initial extreme cystic disease in the femoral head failed due to femoral loosening. Survivorship was 95.2% at 5 years and 81.0% at 10 years.We found that XLPE wear was not implicated in these failures, which were primarily attributed to poor bone quality of the femoral head, early bone preparation, cementing technique and excessive head reaming to near the neck diameter, necessitated for the implantation of a thick two-part socket.

Do clinical and quality of life scores change over time after hip resurfacing?

BACKGROUND: Metal-on-metal hip resurfacing (MOMHR) is an alternative to total hip replacement in young and active patients but little is known about the evolution of clinical outcome scores of hip resurfacing over time.The purpose of this study was 1) to assess the long-term evolution of UCLA hip scores and SF-12 Quality of life evaluations in a group of patients treated with hip resurfacing arthroplasty, 2) to determine whether the age of the patient at surgery influenced these outcome measurements, and 3) whether the changes in SF-12 scores are comparable with those of the general US population. PATIENT AND METHODS: A total of 100 patients with unilateral, unrevised, Charnley class A MOMHR were retrospectively selected for the study. UCLA and SF-12 scores were calculated preoperatively, short-term postoperatively, and beyond 10 years. RESULTS: There was a decrease in the UCLA function and activity scores, and in the SF-12 physical scores between the short-term and the last follow-up at a minimum of 10 years. However, pain, walking, and SF-12 mental scores were maintained through the last follow-up. Furthermore, the SF-12 physical scores at last follow-up were comparable with those of the general US population while the mental scores were greater. There were no significant differences between the two age groups at any of the follow-up intervals for any outcome measurement. CONCLUSIONS: While there is a slight decline in physical function following hip resurfacing over time, pain relief, walking ability, and quality of life are maintained.

The effect of patient selection and surgical technique on the results of Conserve® Plus hip resurfacing--3.5- to 14-year follow-up.

The results of metal-on-metal hip Conserve® Plus resurfacings with up to 14 years of follow-up with and without risk factors of small component size and/or large femoral defects were compared as performed with either first- or second-generation surgical techniques. There was a 99.7% survivorship at ten years for ideal hips (large components and small defects) and a 95.3% survivorship for hips with risk factors optimized technique has measurably improved durability in patients with risk factors at the 8-year mark. The lessons learned can help offset the observed learning curve of resurfacing.

Incidence and significance of femoral neck narrowing in the first 500 Conserve® Plus series of hip resurfacing cases: a clinical and histologic study.

Narrowing of the femoral neck after metal-on-metal hip resurfacing arthoplasty has been reported as a common radiologic feature, although its significance is still unknown. This study reports the presence and significance of neck narrowing in the first 500 consecutive Conserve® Plus metal-on-metal hip resurfacings in 431 patients.

Mid-to-long term follow-up of Transcend metal-on-metal versus Interseal metal-on-polyethylene bearings in total hip arthroplasty.

Second-generation metal-on-metal total hip arthroplasty (THA) was introduced in the early 1990s to address osteolysis and aseptic loosening resulting from polyethylene wear. We present a comparison between the Transcend metal-on-metal and Interseal metal-on-polyethylene THAs. Thirty-seven hips with Transcend metal bearings and 36 hips with Interseal polyethylene acetabular liners but identical acetabular shells were reviewed to determine clinical performance, radiographic changes, and survivorship. Patients with higher anticipated activity levels were selected to receive the Transcend bearing. Mean follow-up time was 107.0 months for the Transcend group, and 90.4 months for the Interseal group. There were no significant differences between the Transcend and Interseal groups for mode of failure and survivorship, which is notable considering the younger and more active Transcend group. However, the Transcend group showed significantly better clinical scores, which may have been a result of the selection methods. Neither surface was differentially implicated in osteolysis, aseptic loosening, or adverse local tissue reaction (ALTR). Our study shows a favorable and comparable performance for both systems.

Complications after metal-on-metal hip resurfacing arthroplasty.

This article determines the incidence and cause of the complications commonly associated with metal-on-metal hip resurfacing implants and the proposed methods to prevent these complications. The literature available in PubMed was reviewed. Complication rates after hip resurfacing are low, and the procedure has shown both safety and efficacy in the hands of surgeons trained in specialized centers. Proper surgical technique can further reduce the incidence of femoral neck fracture, component loosening, and abnormal wear of the prosthesis. A more systematic detection of adverse local tissue reactions is needed to provide accurate assessments of their prevalence.

Failure modes of 433 metal-on-metal hip implants: how, why, and wear.

Metal-on-metal total hip replacements (THRs) and hip resurfacings are coming under increasing scrutiny in light of concerns that they fail because of high wear and elevated metal ions. The aim of this study was to investigate the modes of failure in a collection of 433 metal-on-metal THRs and hip resurfacings and to examine the correlations between the reasons for revision and a range of patient and implant variables considered relevant to implant wear.

Cement technique changes improved hip resurfacing longevity - implant retrieval findings.

BACKGROUND: Most designs of metal-on-metal hip resurfacing utilize cement for femoral fixation, but the amount, application, and distribution of cement varies considerably according to implant design and surgeon preference. In one type of hip resurfacing system (Conserve Plus), the objective was to achieve a 1-mm cement mantle and several millimeters of penetration. In early cases of the senior investigator's (HCA) series, cement fixation failures were noted, and this prompted changes in femoral head preparation and cement application techniques. Survivorship improved following implementation of these changes. The aim of the current study was to examine revised femoral components for the cement distribution, especially in cases where the improved techniques were subsequently applied. METHOD: Fifteen resurfacing femoral components were sectioned and the slices were radiographed and photographed, and the amount and distribution of cement were examined and measured. Cases representative of the evolving cementing techniques were examined in detail. RESULTS: There was considerable variation observed in the amount and distribution of cement, partly as a consequence of variable bone quality in this "all-comers" included series. The cement analyses showed that the newer cementing techniques helped to reduce over-penetration while providing better cement interdigitation. The use of extra fixation holes and cementing the stem in cases with poor bone quality were associated with improved cement-to-bone contact area. CONCLUSION: Meticulous femoral head preparation was helpful in providing durable cement fixation and is essential in cases with poor bone quality.