High Survivorship With Cementless Stems and Cortical Strut Allografts for Large Femoral Bone Defects in Revision THA

Background

Numerous studies have investigated the clinical and radiographic results of revision THAs with use of cementless stems and cortical strut allografts. However, to our knowledge, no long-term followup studies have evaluated patients undergoing revision THA with use of cortical strut allografts where the allografts provided the primary stability for extensively coated femoral stems in the presence of extensive femoral diaphyseal bone defects.

Question/purposes

We performed this study to determine (1) validated outcomes scores; (2) radiographic signs of fixation and allograft healing; (3) frequency of complications; and (4) survivorship of the components after use of cortical strut onlay allografts in Types IIIB and IV femoral diaphyseal bone defects.

Methods

Between 1994 and 2003, we performed 140 revision THAs in 130 patients with Paprosky Types IIIB and IV femoral diaphyseal defects. The patients were treated using extensively coated femoral stems and cortical strut allografts because primary axial or rotational stability could not be achieved without grafting. Ten of the patients (10 hips; 7.7%) were lost to followup or died before 10 years; the remaining 120 patients (130 hips) represent the study group in this retrospective study. There were 66 men and 54 women. Their mean age at the time of index surgery was 59 ± 18 years (range, 36–67 years). The primary diagnosis was predominantly osteonecrosis of the femoral head (53%). The most common reason for revision was aseptic loosening (97%), followed by periprosthetic fracture (3%). The mean time from primary to revision THA was 12 years (range, 8–27 years). The mean duration of followup was 16.1 years (range, 12–20 years).

Results

The mean Harris hip score was 39 ± 10 points before revision and improved to 86 ± 14 points at 16 years followup (p = 0.02). The mean preoperative WOMAC score was 62 ± 29 (41–91) points and improved to 22 ± 19 (11–51) points at 16 years followup (p = 0.003). Of the 130 stems, 113 (87%) had bone ingrowth, five (4%) had stable fibrous ingrowth, and 12 (9%) were unstable. All allografts were incorporated. Four hips (3%) had a displaced femoral shaft fracture at the stem tip; four (3%) had a postoperative dislocation; and six (5%) had early postoperative infection. Kaplan-Meier survivorship analysis, with revision or radiographic failure as the endpoint, revealed that the 16-year rate of survival of the components was 91% (95% CI, 0.88%–0.96%).

Conclusion

Supportive cortical strut onlay allografts provided high survivorship beyond 12 years of followup in revision THAs. Future studies might compare this approach with allograft-prosthesis composites, proximal femoral replacement, or modular fluted, tapered stems.

Level of Evidence

Level IV, therapeutic study.     

Conversion of Stemmed Hemi- or Total to Reverse Total Shoulder Arthroplasty: Advantages of a Modular Stem Design

Background

If revision of a failed anatomic hemiarthroplasty or total shoulder arthroplasty is uncertain to preserve or restore satisfactory rotator cuff function, conversion to a reverse total shoulder arthroplasty has become the preferred treatment, at least for elderly patients. However, revision of a well-fixed humeral stem has the potential risk of loss of humeral bone stock, nerve injury, periprosthetic fracture, and malunion or nonunion of a humeral osteotomy with later humeral component loosening.

Questions/purposes

The purposes of this study were to determine whether preservation of a modular stem is associated with (1) less blood loss and operative time; (2) fewer perioperative and postoperative complications, including reoperations and revisions; and/or (3) improved Constant and Murley scores and subjective shoulder values for conversion to a reverse total shoulder arthroplasty compared with stem revision.

Methods

Between 2005 and 2011, 48 hemiarthroplasties and eight total shoulder arthroplasties (total = 56 shoulders; 54 patients) were converted to an Anatomical™ reverse total shoulder arthroplasty system without (n = 13) or with (n = 43) stem exchange. Complications and revisions for all patients were tallied through review of medical and surgical records. The outcomes scores included the Constant and Murley score and the subjective shoulder value. Complete clinical followup was available on 80% of shoulders (43 patients; 45 of 56 procedures, 32 with and 13 without stem exchange) at a minimum of 12 months (mean, 37 months; range, 12–83 months).

Results

Blood loss averaged 485 mL (range, 300–700 mL; SD, 151 mL) and surgical time averaged 118 minutes (range, 90–160 minutes; SD, 21 minutes) without stem exchange and 831 mL (range, 350–2000 mL; SD, 400 mL) and 176 minutes (range, 120–300 minutes; SD, 42 minutes) with stem exchange (p = 0.001). Intraoperative complications (8% versus 30%; odds ratio [OR], 5.2) and reinterventions (8% versus 14%; OR, 1.9) were substantially fewer in patients without stem exchange. The complication rate leading to dropout from the study was substantial in the stem revision group (six patients; 43 shoulders [14%]), but there were no complication-related dropouts in the stem-retaining group. If, however, such complications could be avoided, with the numbers available we detected no difference in the functional outcome between the two groups.

Conclusions

Patients undergoing revision of stemmed hemiarthroplasty or total to reverse total shoulder arthroplasty without stem exchange had less intraoperative blood loss and operative time, fewer intraoperative complications, and fewer revisions than did patients whose index revision procedures included a full stem exchange. Therefore modularity of a shoulder arthroplasty system has substantial advantages if conversion to reverse total shoulder arthroplasty becomes necessary and should be considered as prerequisite for stemmed shoulder arthroplasty systems.

Level of Evidence

Level III, therapeutic study.     

Do Rerevision Rates Differ After First-time Revision of Primary THA With a Cemented and Cementless Femoral Component?

Background

Worldwide use of cementless fixation for total hip arthroplasty (THA) is on the rise despite some evidence from the world’s registries suggesting inferior survivorship compared with cemented techniques. The patterns of bone loss associated with failed cementless and cemented THAs may prejudice the results of future revision procedures; however, this has not been documented.

Questions/purposes

The purpose of this study was to compare (1) the risk for rerevision of first revision THA; (2) the patterns of femoral bone loss at the time of first revision of primary THA; (3) the reasons for first revision of primary THA; and (4) the time to first revision of primary THA between primary cementless and cemented femoral components.

Methods

Primary THAs with cemented (n = 1791) and uncemented (n = 805) femoral components that subsequently sustained first revision of the femoral component were identified from the Danish Hip Arthroplasty Registry (DHR). As of 2012, 120,988 primary THAs and 19,282 revisions were registered in the DHR with completeness of 97% and 90% for primary and revision THA, respectively. Median followup for revisions of primary THA with cemented and cementless femoral component was 4 years (range, 0–17 years) and 2 years (range, 0–16 years), respectively. Survival of first revision THA, with second revision of the femur as outcome, was evaluated using hazard ratios (HRs) with 95% confidence interval (CI) adjusting for potential confounding. All patient- and surgery-related data are collected from Danish medical databases. Recording of bone defects in the DHR is based on surgeons’ intraoperative findings.

Results

With the numbers studied, we found no differences in the risk of second revision between the overall cohort between cementless and cemented techniques (HR, 1.32; 95% CI, 0.97–1.80; p = 0.076); however, a second revision for any reason was more likely in patients < 70 years old in whom the index arthroplasty was performed using a cementless technique (HR, 1.48; 95% CI, 1.01–2.17; p = 0.046). Increasingly severe femoral bone defects of type II (30% [532 of 1791] versus 13% [104 of 805]; p < 0.001) type III (11% [200 of 1791] versus 2% [12 of 805]; p < 0.001) and type IV (1% [26 of 1791] versus 0.4% [three of 805]; p = 0.016) were more frequent at revisions of cemented femoral components compared with cementless femoral components. Indications for first revision differed between primary cemented and uncemented femoral components, because a larger proportion of cemented femoral components was revised as a result of aseptic loosening compared with cementless femoral components (74% [1329 of 1791] versus 25% [197 of 805]; p < 0.001), whereas a larger proportion of cementless femoral components was revised as a result of a fracture compared with cemented femoral components (46% [371 of 805] versus 10% [168 of 1791]; p < 0.001). Failure before 5 years was more likely in cementless femoral components than cemented femoral components (91% [733 of 805] versus 44% [749 of 1791], p < 0.001).

Conclusions

We found no differences in the risk of second revision in the overall cohort between cementless and cemented techniques; however, we observed an increased risk for rerevision THA performed on patients < 70 years whose index THAs were performed using cementless components when looking at all causes for revision, even after adjusting for the most likely confounding factors. Our data suggest that increased use of cementless fixation in primary THA may lead to inferior survivorship of first revision THA.

Level of Evidence

Level III, therapeutic study.     

What Middle Phalanx Base Fracture Characteristics are Most Reliable and Useful for Surgical Decision-making?

Background

Fracture-dislocations of the proximal interphalangeal joint are vexing because subluxation and articular damage can lead to arthrosis and the treatments are imperfect. Ideally, a surgeon could advise a patient, based on radiographs, when the risk of problems merits operative intervention, but it is unclear if middle phalanx base fracture characteristics are sufficiently reliable to be useful for surgical decision making.

Questions/purposes

We evaluated (1) the degree of interobserver agreement as a function of fracture characteristics, (2) the differences in interobserver agreement between experienced and less-experienced hand surgeons, and (3) what fracture characteristics and surgeon characteristics were associated with the decision for operative treatment.

Methods

Ninety-nine (33%) of 296 hand surgeons evaluated 21 intraarticular middle phalanx base fractures on lateral radiographs. Eighty-one surgeons (82%) were in academic practice and 57 (58%) had less than 10 years experience. Participants assessed six fracture characteristics and recommended treatment (nonoperative or operative: extension block pinning, external fixation, open reduction and internal fixation, volar plate arthroplasty, or hemihamate autograft arthroplasty) for all cases.

Results

With all surgeons pooled together, the interobserver agreement for fracture characteristics was substantial for assessment of a 2-mm articular step or gap (kappa, 0.73; 95% CI, 0.60–0.86; p < 0.001), subluxation or dislocation (kappa, 0.72; 95% CI, 0.58–0.86; p < 0.001), and percentage of articular surface involved (intraclass correlation coefficient [ICC], 0.67; 95% CI, 0.54–0.81; p < 0.001); moderate for comminution (kappa, 0.55; 95% CI, 0.39–0.70; p < 0.001) and stability (kappa, 0.54; 95% CI, 0.39–0.69; p < 0.001); and fair for the number of fracture fragments (ICC, 0.39; 95% CI, 0.27–0.57; p < 0.001). When recommending treatment, interobserver agreement was substantial (kappa, 0.69; 95% CI, 0.50–0.88; p < 0.001) for the recommendation to operate or not to operate, but only fair (kappa, 0.34; 95% CI, 0.21–0.47; p < 0.001) for the specific type of treatment, indicating variation in operative techniques. There were no differences in agreement for any of the fracture characteristics or treatment preference between less-experienced and more-experienced surgeons, although statistical power on this comparison was low. None of the surgeon characteristics was associated with the decision for operative treatment, whereas all fracture characteristics were, except for stable and uncertain joint stability. Articular step or gap (β, 0.90; R-squared, 0.89; 95% CI, 0.75–1.05; p < 0.001), likelihood of subluxation or dislocation (β, 0.80; R-squared, 0.76; 95% CI, 0.59–1.02; p < 0.001), and unstable fractures (β, 0.88; R-squared, 0.81; 95% CI, 0.67–1.1; p < 0.001), are most strongly associated with the decision for operative treatment.

Conclusions

We found that assessment of a step or gap and likelihood of subluxation were most reliable and are strongly associated with the decision for operative treatment. Surgeons largely agree on which fractures might benefit from surgery, and the variation seems to be with the operative technique. Efforts at improving the care of these fractures should focus on the comparative effectiveness of the various operative treatment options.

Level of Evidence

Level III, diagnostic study.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-015-4394-7) contains supplementary material, which is available to authorized users.     

Morbidity and Readmission After Open Reduction and Internal Fixation of Ankle Fractures Are Associated With Preoperative Patient Characteristics

Background

Ankle fractures are common and can be associated with severe morbidity. Risk factors for short-term adverse events and readmission after open reduction and internal fixation (ORIF) of ankle fractures have not been fully characterized.

Questions/purposes

The purpose of our study was to determine patient rates and risk factors for (1) any adverse event; (2) severe adverse events; (3) infectious complications; and (4) readmission after ORIF of ankle fractures.

Methods

Patients who underwent ORIF for ankle fracture from 2005 to 2012 were identified in the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP^®) database using International Classification of Diseases, 9^th Revision and Current Procedural Terminology codes. Patients with missing perioperative data were excluded from this study. Patient characteristics were tested for association with any adverse event, severe adverse events, infectious complications, and readmission using bivariate and multivariate logistic regression analyses.

Results

Of the 4412 patients identified, 5% had an adverse event. Any adverse event was associated with insulin-dependent diabetes mellitus (IDDM; odds ratio [OR], 2.05; 95% confidence interval [CI], 1.35–3.1; p = 0.001), age ≥ 60 years (OR, 1.97; 95% CI, 1.22–3.2; p = 0.006), American Society of Anesthesiologists classification ≥ 3 (OR, 1.69; 95% CI, 1.2–2.37; p = 0.002), bimalleolar fracture (OR, 1.6; 95% CI, 1.08–2.37; p = 0.020), hypertension (OR, 1.47; 95% CI, 1.04–2.09; p = 0.031), and dependent functional status (OR, 1.47; 95% CI, 1.02–2.14; p = 0.040) on multivariate analysis. Severe adverse events occurred in 3.56% and were associated with ASA classification ≥ 3 (OR, 2.01; p = 0.001), pulmonary disease (OR, 1.9; p = 0.004), dependent functional status (OR, 1.8; p = 0.005), and hypertension (OR, 1.65; p = 0.021). Infectious complications occurred in 1.75% and were associated with IDDM (OR, 3.51; p < 0.001), dependent functional status (OR, 2.4; p = 0.002), age ≥ 60 years (OR, 2.28; p = 0.028), and bimalleolar fracture (OR, 2.19; p = 0.030). Readmission occurred in 3.17% and was associated with ASA classification ≥ 3 (OR, 2.01; p = 0.017).

Conclusions

IDDM was associated with an increased rate of adverse events after ankle fracture ORIF, whereas noninsulin-dependent diabetes mellitus was not. IDDM management deserves future study, particularly with respect to glycemic control, a potential confounder that could not be assessed with the ACS-NSQIP registry. Increased ASA class was associated with readmission, and future prospective investigations should evaluate the effectiveness of increasing the discharge threshold, discharging to extended-care facilities, and/or home nursing evaluations in this at-risk population.

Level of Evidence

Level III, prognostic study.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-014-4005-z) contains supplementary material, which is available to authorized users.     

What is the Best Clinical Test for Assessment of the Teres Minor in Massive Rotator Cuff Tears?

Background

Few studies define the clinical signs to evaluate the integrity of teres minor in patients with massive rotator cuff tears. CT and MRI, with or without an arthrogram, can be limited by image quality, soft tissue density, motion artifact, and interobserver reliability. Additionally, the ill-defined junction between the infraspinatus and teres minor and the larger muscle-to-tendon ratio of the teres minor can contribute to error. Therefore, we wished to determine the validity of clinical testing for teres minor tears.

Question/Purposes

The aim of this study was to determine the accuracy of commonly used clinical signs (external rotation lag sign, drop sign, and the Patte test) for diagnosing the teres minor’s integrity.

Methods

We performed a prospective evaluation of patients referred to our shoulder clinic for massive rotator cuff tears determined by CT arthrograms. The posterosuperior rotator cuff was examined clinically and correlated with CT arthrograms. We assessed interobserver reliability for CT assessment and used three different clinical tests of teres minor function (the external rotation lag sign, drop sign, and the Patte test). One hundred patients with a mean age of 68 years were available for the analysis.

Results

The most accurate test for teres minor dysfunction was an external rotation lag sign greater than 40°, which had a sensitivity of 100% (95% CI, 80%–100%) and a specificity of 92% (95% CI, 84%–96%). External rotation lag signs greater than 10° had a sensitivity of 100% (95% CI, 80%–100%) and a specificity of 51% (95% CI, 40%–61%). The Patte sign had a sensitivity of 93% (95% CI, 70%–99%) and a specificity of 72% (95% CI, 61%–80%). The drop sign had a sensitivity of 87% (95% CI, 62%–96%) and a specificity of 88% (95% CI, 80%–93%). An external rotation lag sign greater than 40° was more specific than an external rotation lag sign greater than 10° (p < 0.001), and a Patte sign (p < 0.001), but was not more specific than the drop sign (p < 0.47). There was poor correlation between involvement of the teres minor and loss of active external rotation.

Conclusions

Clinical signs can predict anatomic patterns of teres minor dysfunction with good accuracy in patients with massive rotator cuff tears. This study showed that the most accurate test for teres minor dysfunction is an external rotation lag sign and that most patients’ posterior rotator cuff tears do not lose active external rotation. Because imaging is not always accurate, examination for integrity of the teres minor is important because it may be one of the most important variables affecting the outcome of reverse shoulder arthroplasty for massive rotator cuff tears, and the functional effects of tears in this muscle on day to day activities can be significant. Additionally, teres minor integrity affects the outcomes of tendon transfers, therefore knowledge of its condition is important in planning repairs.

Level of Evidence

Level III, diagnostic study.     

Total Femur Replacement After Tumor Resection: Limb Salvage Usually Achieved But Complications and Failures are Common

Background

Primary bone or soft tissue tumors of the femur sometimes present with severe and extensive bone destruction, leaving few limb-salvage options other than total femur replacement. However, there are few data available regarding total femur replacement and, in particular, regarding implant failures.

Questions/purposes

We asked: (1) What are the revision-free and overall implant survival rates of conventional total femur replacements in patients treated for sarcoma of the femur or soft tissues? (2) What are the revision-free and overall implant survival rates of expandable total femur replacements in skeletally immature patients? (3) Using the comprehensive International Society of Limb Salvage failure-mode classification, what types of complications occur with conventional and expandable total femur replacements?

Patients and Methods

Our retrospective, single-center cohort study was based on data prospectively collected for 50 patients who received a total femur replacement after tumor resection for indications other than carcinoma or metastatic disease. Of the 50 patients, six (12%) were lost to followup before 6 months. Ten of the remaining 44 patients received expandable implants. The mean followup was 57 months (range, 1–280 months) and 172 months (range, 43–289 months) for patients who underwent conventional and expandable total femur replacements, respectively. For implant survival, competing risk analyses were used.

Results

At 5 years, revision-free implant survival of conventional total femur replacements was 48% (95% CI, 0.37–0.73), and overall implant survival was 97% (95% CI, 0.004–0.20). Five-year revision-free implant survival of expandable total femur replacements was 30% (95% CI, 0.47–1.00) and overall implant survival was 100%. With conventional total femur replacements soft tissue failures occurred in 13 of 34 patients, structural failures in three, infection in six, and local tumor progression in one. No patient had aseptic loosening with conventional total femur replacements, but hip disarticulation occurred in two patients owing to extensive wound-healing problems and infection. With expandable total femur replacements soft tissue failure, aseptic loosening, and infection occurred in one patient each of 10, and structural failures in three of 10 (two periprosthetic fractures, one loosening of an enhanced tendon anchor). No hip disarticulations were performed. Additionally expandable total femur replacement-related failures included hip instability in eight of 10 patients, contractures attributable to massive scar tissue in six, and defect of the implant’s expansion mechanism in four patients.

Conclusions

Although the indications for total femoral resection are rare, we think that total femur replacement is a reasonable treatment option for reconstruction of massive femoral bone defects after tumor resection in adults and skeletally immature patients, and results in limb salvage in most patients.

Level of Evidence

Level IV, therapeutic study.     

Premature Therapeutic Antimicrobial Treatments Can Compromise the Diagnosis of Late Periprosthetic Joint Infection

Background

In the absence of positive cultures and draining sinuses, the diagnosis of periprosthetic joint infection (PJI) relies on laboratory values. It is unknown if administration of antibiotics within 2 weeks before diagnostic evaluations can affect these tests in patients with PJI.

Questions/purposes

The purpose of this study was to investigate the correlation of antibiotic administration with (1) fluctuations in the synovial fluid and serology laboratory values; and (2) sensitivity of the diagnostic tests in patients with late PJI (per Musculoskeletal Infection Society [MSIS] criteria).

Methods

Synovial white blood cell (WBC) count, polymorphonuclear neutrophil (PMN) percentage, and serum erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) as well as culture results were investigated in 161 patients undergoing total knee arthroplasty with late PJI diagnosed with the MSIS criteria. Depending on whether presampling antibiotics were used, patients were divided in two groups (53 [33%] patients were on antibiotics). The median laboratory values and the false-negative rates were compared between the two groups.

Results

The median of all variables were lower in the antibiotic group compared with the other group: ESR (mm/hr): 70 versus 85, difference of medians (DOM) = 15 mm/hr, p = 0.018; CRP (mg/L): 72 versus 130, DOM = 58 mg/L, p = 0.038; synovial WBC (cells/μL): 29,170 versus 46,900, DOM = 17,730, p = 0.022; and synovial PMN%: 88.5% versus 92.5%, DOM = 4%, p = 0.012. Furthermore, using the MSIS cutoffs, the false-negative rates of several parameters were higher in the antibiotic group; ESR: 19.2% (nine of 47) versus 6.1% (six of 99) (relative risk, 3.1; 95% confidence interval [CI], 1.2–8.3; p = 0.020); CRP: 14.9% (seven of 47) versus 2.00% (two of 100) (relative risk, 7.4; 95% CI, 1.6–34.4); PMN%: 23.1% (12 of 52) versus 9.4% (10 of 106) (relative risk, 2.4; 95% CI, 1.1–5.2; p = 0.027). Patients in the antibiotic group also had higher rates of negative cultures: 26.4% (14 of 53) versus 12.9% (14 of 108) (relative risk, 2.0; 95% CI, 1.05–3.9; p = 0.046).

Conclusions

It appears that premature antibiotic treatments are associated with lower medians of diagnostic laboratory values. Thus, and in line with the guideline recommendations of the American Academy of Orthopaedic Surgeons, patients with suspected late-PJI should not receive antibiotics until the diagnosis is reached or refuted.

Level of Evidence

Level III, diagnostic study.     

Low-intensity Pulsed Ultrasound Enhances Bone Repair in a Rabbit Model of Steroid-associated Osteonecrosis

Background

Steroids are a leading cause of femoral head osteonecrosis. Currently there are no medications available to prevent and/or treat steroid-associated osteonecrosis. Low-intensity pulsed ultrasound (LIPUS) was approved by the FDA for treating delayed union of bone fractures. Some studies have reported that LIPUS can enhance bone formation and local blood flow in an animal model of fracture healing. However, whether the effect of osteogenesis and neovascularization by LIPUS can enhance the repair progress in steroid-associated osteonecrosis is unknown.

Questions/purposes

We hypothesized that LIPUS may facilitate osteogenesis and neovascularization in the reparative processes of steroid-associated osteonecrosis. Using a rabbit animal model, we asked whether LIPUS affects (1) bone strength and trabecular architecture; (2) blood vessel number and diameter; and (3) BMP-2 and VEGF expression.

Methods

Bilateral femoral head necrosis was induced by lipopolysaccharide and methylprednisolone in 24 rabbits. The left femoral heads of rabbits received LIPUS therapy (200 mW/cm²) for 20 minutes daily and were classified as the LIPUS group. The right femoral heads of the same rabbits did not receive therapy and were classified as the control group. All rabbits were euthanized 12 weeks after LIPUS therapy. Micro-CT, biomechanical testing, histologic evaluation, immunohistochemistry, quantitative real-time PCR, and Western blot were used for examination of the effects of LIPUS.

Results

Twelve weeks after LIPUS treatment, the loading strength in the control group was 355 ± 38 N (95% CI, 315–394 N), which was lower (p = 0.028) than that in the LIPUS group (441 ± 78 N; 95% CI, 359–524 N). The bone tissue volume density (bone volume/total volume) in the LIPUS group (49.29% ± 12.37%; 95 % CI, 36.31%–62.27%) was higher (p = 0.022) than that in the control group (37.93% ± 8.37%; 95 % CI, 29.15%–46.72%). The percentage of empty osteocyte lacunae in the LIPUS group (17% ± 4%; 95% CI, 15%–20%) was lower (p = 0.002) than that in the control group (26% ± 9%; 95% CI, 21%–32%). The mineral apposition rate (μm/day) in the LIPUS group (2.3 ± 0.8 μm/day; 95% CI, 1.8 2.8 μm/day) was higher (p = 0.001) than that in the control group (1.6 ± 0.3 μm/day; 95% CL, 1.4–1.8 μm/day). The number of blood vessels in the LIPUS group (7.8 ± 3.6/mm²; 95% CI, 5.5–10.1 mm²) was greater (p = 0.025) than the number in the control group (5.7 ± 2.6/mm²; 95% CI, 4.0–7.3 mm²). Messenger RNA (mRNA) and protein expression of BMP-2 in the LIPUS group (75 ± 7, 95% CI, 70–79; and 30 ± 3, 95% CI, 28–31) were higher (both p < 0.001) than those in the control groups (46 ± 5, 95% CI, 43–49; and 15 ± 2, 95% CI, 14–16). However, there were no differences (p = 0.114 and 0.124) in mRNA and protein expression of vascular endothelial growth factor between the control (26 ± 3, 95% CI, 24–28; and 22 ± 6, 95% CI, 18–26) and LIPUS groups (28 ± 2, 95% CI, 26–29; and 23 ± 6, 95% CI, 19–27).

Conclusions

The results of this study indicate that LIPUS promotes osteogenesis and neovascularization, thus promoting bone repair in this steroid-associated osteonecrosis model.

Clinical Relevance

LIPUS may be a promising modality for the treatment of early-stage steroid-associated osteonecrosis. Further research, including clinical trials to determine whether LIPUS has a therapeutic effect on patients with early-onset steroid-associated osteonecrosis may be warranted.     

Radiographic Subsidence in Asymptomatic Patients After THR Using the Furlong Active HAP Stem

Background

The short, tapered, collarless Furlong Active stem has been recently associated in the published literature with significant subsidence using Roentgen stereophotogrammetric analysis.

Questions/Purposes

The purpose of this study was to analyze the short-term radiographic subsidence in Furlong Active HAP stems and correlate the results with the age, gender, bone morphology, and bone quality of the proximal femur, stem diameter, and medullary canal filling.

Methods

Sixty-five consecutive patients (70 hips) receiving the Furlong Active HAP stems were enrolled in this prospective series. The average follow-up was 2.99 ± 1.38 years. All patients were evaluated clinically using the Harris Hip Score (HHS) and radiographically for femoral stem subsidence. In addition, proximal femoral osteopenia, proximal femur morphology, and medullary canal filling were also evaluated.

Results

The average subsidence was 2.4 mm (from 0 to 13 mm) at the end of the follow-up period. The average HHS score at the end of follow-up was 90 (range, 81–98). There was one intraoperative fracture.

Conclusions

Of the Furlong Active stems 61% subsided with initial weight bearing. Subsidence is higher in males, but no correlation has been found with age, stem diameter, morphology, osteopenia, or canal filling.

Electronic supplementary material

The online version of this article (doi:10.1007/s11420-013-9342-z) contains supplementary material, which is available to authorized users.     

Can Cytoprotective Cobalt Protoporphyrin Protect Skeletal Muscle and Muscle-derived Stem Cells From Ischemic Injury?

Background

Extremity trauma is the most common injury seen in combat hospitals as well as in civilian trauma centers. Major skeletal muscle injuries that are complicated by ischemia often result in substantial muscle loss, residual disability, or even amputation, yet few treatment options are available. A therapy that would increase skeletal muscle tolerance to hypoxic damage could reduce acute myocyte loss and enhance preservation of muscle mass in these situations.

Questions/purposes

In these experiments, we investigated (1) whether cobalt protoporphyrin (CoPP), a pharmacologic inducer of cytoprotective heme oxygenase-1 (HO-1), would upregulate HO-1 expression and activity in skeletal muscle, tested in muscle-derived stem cells (MDSCs); and (2) whether CoPP exposure would protect MDSCs from cell death during in vitro hypoxia/reoxygenation. Then, using an in vivo mouse model of hindlimb ischemia/reperfusion injury, we examined (3) whether CoPP pharmacotherapy would reduce skeletal muscle damage when delivered after injury; and (4) whether it would alter the host inflammatory response to injury.

Methods

MDSCs were exposed in vitro to a single dose of 25 μΜ CoPP and harvested over 24 to 96 hours, assessing HO-1 protein expression by Western blot densitometry and HO-1 enzyme activity by cGMP levels. To generate hypoxia/reoxygenation stress, MDSCs were treated in vitro with phosphate-buffered saline (vehicle), CoPP, or CoPP plus an HO-1 inhibitor, tin protoporphyrin (SnPP), and then subjected to 5 hours of hypoxia (< 0.5% O₂) followed by 24 hours of reoxygenation and evaluated for apoptosis. In vivo, hindlimb ischemia/reperfusion injury was produced in mice by unilateral 2-hour tourniquet application followed by 24 hours of reperfusion. In three postinjury treatment groups (n = 7 mice/group), CoPP was administered intraperitoneally during ischemia, at the onset of reperfusion, or 1 hour later. Two control groups of mice with the same injury received phosphate-buffered saline (vehicle) or the HO-1 inhibitor, SnPP. Myocyte damage in the gastrocnemius and tibialis anterior muscles was determined by uptake of intraperitoneally delivered Evans blue dye (EBD), quantified by image analysis. On serial sections, inflammation was gauged by the mean myeloperoxidase staining intensity per unit area over the entirety of each muscle.

Results

In MDSCs, a single exposure to CoPP increased HO-1 protein expression and enzyme activity, both of which were sustained for 96 hours. CoPP treatment of MDSCs reduced apoptotic cell populations by 55% after in vitro hypoxia/reoxygenation injury (from a mean of 57.3% apoptotic cells in vehicle-treated controls to 25.7% in CoPP-treated cells, mean difference 31.6%; confidence interval [CI], 28.1–35.0; p < 0.001). In the hindlimb ischemia/reperfusion model, CoPP delivered during ischemia produced a 38% reduction in myocyte damage in the gastrocnemius muscle (from 86.4% ± 7% EBD⁺ myofibers in vehicle-treated, injured controls to 53.2% EBD⁺ in CoPP-treated muscle, mean difference 33.2%; 95% CI, 18.3, 48.4; p < 0.001). A 30% reduction in injury to the gastrocnemius was seen with drug delivery at the onset of reperfusion (to 60.6% ± 13% EBD⁺ with CoPP treatment, mean difference 25.8%; CI, 12.2–39.4; p < 0.001). In the tibialis anterior, however, myocyte damage was decreased only when CoPP was given at the onset of reperfusion, resulting in a 27% reduction in injury (from 78.8% ± 8% EBD⁺ myofibers in injured controls to 58.3% ± 14% with CoPP treatment, mean difference 20.5%; CI, 6.1–35.0; p = 0.004). Delaying CoPP delivery until 1 hour after tourniquet release obviated the protective effect in both muscles. Mean MPO staining intensity per unit area, indicating the host inflammatory response, decreased by 27–34% across both the gastrocnemius and tibialis anterior muscles when CoPP was given either during ischemia or at the time of reperfusion. Delaying drug delivery until 1 hour after the start of reperfusion abrogated this antiinflammatory effect.

Conclusions

CoPP can decrease skeletal muscle damage when given early in the course of ischemia/reperfusion injury and also provide protection for regenerative stem cell populations.

Clinical Relevance

Pharmacotherapy with HO-1 inducers, delivered in the field, on hospital arrival, or during trauma surgery, may improve preservation of muscle mass and muscle-inherent stem cells after severe ischemic limb injury.

Electronic supplementary material

The online version of this article (doi:10.1007/s11999-015-4332-8) contains supplementary material, which is available to authorized users.     

How Does?Bone Strength?Compare Across Sex,Site, and Ethnicity?

Background

The risk of fragility fractures in the United States is approximately 2.5 times greater among black and white women compared with their male counterparts. On average, men of both ethnicities have wider bones of greater cortical mass compared with the narrower bones of lower cortical mass among women. However, it remains uncertain whether the low cortical area observed in the long bones of women is consistent with their narrower bone diameter or if their cortical area is reduced beyond that which is expected for the sex differences in body size and external bone size.

Questions/purposes

We asked (1) do black and white women consistently have narrower bones of less strength across long bones compared with black and white men; and (2) do all long bones of black and white women have reduced cortical area compared with black and white men?

Methods

Peripheral quantitative CT was used to quantify bone strength and cross-sectional morphology from the major long bones of 125 white and 115 black adult men and women (20–35 years of age). Regression analyses were used to test for differences in bone strength and cortical area after for adjusting for either body size, bone size, or both.

Results

After adjusting bone strength for body size, regression analyses showed that black women had lower bone strength compared with black men (women: mean = 298.7–25,522 mg HA mm⁴, 95% confidence interval [CI], 270–27,692 mg HA mm⁴; men: mean = 381.6–30,945 mg HA mm⁴, 95% CI, 358.2–32,853 mg HA mm⁴; percent difference = 12%–38%, p = 0.06–0.0001). Similarly, white women also had lower bone strength compared with white men (women: mean = 229.5–22,892 mg HA mm⁴, 95% CI, 209.3–24,539 mg HA mm⁴; men: mean = 314.3–29,986 mg HA mm⁴, 95% CI, 297.3–31,331 mg HA mm⁴; percent difference = 27%–49%, p = 0.0001). All long bones of women for both ethnicities showed lower cortical area compared with men. After accounting for both body size and external bone size, black women (women: mean = 43.25–357.70 mm², 95% CI, 41.45–367.52 mm²; men: mean = 48.06–400.10 mm², 95% CI, 46.67–408.72; percent difference = 6%–25%, p = 0.02–0.0001) and white women (women: mean = 38.53–350.10 mm², 95% CI, 36.99–359.80 mm²; men: mean = 42.06–394.30 mm², 95% CI, 40.95–402.10 mm²; percent difference = 6%–22%, p = 0.02–0.0001) were shown to have lower cortical area than their male counterparts. Therefore, the long bones of women are not only more slender than those of men, but also show a reduced cortical area that is 6% to 25% greater than expected for their external size, depending on the bone being considered.

Conclusions

The long bones of females are not just a more slender version of male long bones. Women have less cortical area than expected for their body size and bone size, which in part explains their reduced bone strength when compared with the more robust bones of men.

Clinical Relevance

The outcome of this assessment may be clinically important for the development of diagnostics and treatment regimens used to combat fractures. Future work should look at how the relationship among parameters reported here translates to the more fracture-prone metaphyseal regions.     

Long-term results of cementless femoral reconstruction following intertrochanteric osteotomy

Purpose

The objective of this retrospective cohort study was to assess the long-term outcome of cementless femoral reconstruction in patients with previous intertrochanteric osteotomy (ITO).

Methods

We evaluated the clinical and radiographic results of a consecutive series of 45 patients (48 hips, mean age 50 years) who had undergone conversion hip replacement following ITO with a cementless, grit-blasted, double-tapered femoral component. Clinical outcome was determined using the Harris hip score. Stem survival for different end points was assessed using Kaplan-Meier survivorship analysis.

Results

At a mean follow-up of 20 (range, 16–24) years, 11 patients (12 hips) had died, and no patient was lost to follow-up. Six patients (six hips) underwent femoral revision, two for infection, three for aseptic loosening and one for periprosthetic fracture. Mean Harris hip score at final follow-up was 78 points (range, 23–100 points). Stem survival for all revisions was 89% (95%CI, 75–95) at 20 years, and survival for aseptic loosening was 93% (95%CI, 80–98).

Conclusions

The long-term results with this type of cementless femoral component in patients with previous intertrochanteric osteotomy are encouraging and compare well to those achieved in patients with normal femoral anatomy.     

Treatment With the SIGN Nail in Closed Diaphyseal Femur Fractures Results in Acceptable Radiographic Alignment

Background

The burden of orthopaedic trauma in the developing world is substantial and disproportionate. SIGN Fracture Care International is a nonprofit organization that has developed and made available to surgeons in resource-limited settings an intramedullary interlocking nail for use in the treatment of femoral and tibial fractures. Instrumentation also is donated with the nail. A prospectively populated database collects information on all procedures performed using this nail. Given the challenging settings and numerous surgeons with varied experience, it is important to document adequate alignment and union using the device.

Questions/purposes

The primary aim of this research was to assess the adequacy of operative reduction of closed diaphyseal femur fractures using the SIGN interlocking intramedullary nail based on radiographic images available in the SIGN database. The secondary aims were to assess correlations between postoperative alignment and several associated variables, including fracture location in the diaphysis, degree of fracture site comminution, and time to surgery. The tertiary aim was to assess the functionality of the SIGN database for radiographic analyses.

Methods

A review of the prospectively populated SIGN database was performed for patients with a diaphyseal femur fracture treated with the SIGN nail, which at the time of the study totaled 32,362 patients. After study size calculations, a random number generator was used to select 500 femur fractures for analysis. Exclusion criteria included open fractures and those without radiographs during the early postoperative period. The following information was recorded: location of the fracture in the diaphysis; fracture classification (AO/Orthopaedic Trauma Association [OTA] classification); degree of comminution (Winquist and Hansen classification); time from injury to surgery; and patient demographics. Measurements of alignment were obtained from the AP and lateral radiographs with malalignment defined as deformity in either the sagittal or coronal plane greater than 5°. Measurements were made manually by the four study authors using on-screen protractor software and interobserver reliability was assessed.

Results

The frequency of malalignment greater than 5° observed on postoperative radiographs was 51 of 501 (10%; 95% CI, 6.5–11.5), and malalignment greater than 10° occurred in eight of 501 (1.6%) of the femurs treated with this nail. Fracture location in the proximal or distal diaphysis was strongly correlated with risk of malalignment, with an odds ratio (OR) of 3.7 (95% CI, 1.5–9.3) for distal versus middle diaphyseal fractures and an OR of 4.7 (95% CI, 1.9–11.5) for proximal versus middle fractures (p < 0.001). Time from injury to surgery greater than 4 weeks also was strongly correlated with risk of malalignment (p < 0.001). Inherent fracture stability, based on fracture site comminution as per the Winquist and Hansen classification (Class 0–1 stable versus 2–4 unstable) showed an OR of 2.3 (95% CI, 1.2–4.3) for malalignment in unstable fractures. Interobserver reliability showed agreement of 88% (95% CI, 83–93) and mean kappa of 0.81 (95% CI, 0.65–0.87). The SIGN database of radiographic images was found to be an excellent source for research purposes with 92% of reviewed radiographs of acceptable quality.

Conclusions

The frequency of malalignment in closed diaphyseal femoral fractures treated with the SIGN nail closely approximated the incidence reported in the literature for North American trauma centers. Increased time from injury to surgery was correlated with increased frequency of malalignment; as humanitarian distribution of the SIGN nail increases, local barriers to timely care should be assessed and improved as possible. Prospective clinical study with followup, despite its inherent challenges in the developing world, would be of great benefit in the future.

Level of Evidence

Level III, therapeutic study.     

Biomechanical comparison of semi-rigid pediatric locking nail versus titanium elastic nails in a femur fracture model

Background

The treatment for length-unstable diaphyseal femur fractures among school-age children is commonly intramedullary elastic nails, with or without end caps. Another possible treatment is the semi-rigid pediatric locking nail (PLN). The purpose of this biomechanical study was to assess the stability of a length-unstable oblique midshaft fracture in a synthetic femur model stabilized with different combinations of intramedullary elastic nails and with a PLN.

Methods

Twenty-four femur models with an intramedullary canal diameter of 10.0 mm were used. Three groups with various combinations of titanium elastic nails (TEN) with end caps and one group with a PLN were tested. An oblique midshaft fracture was created, and the models underwent compression, rotation, flexion/extension, and a varus/valgus test, with 50 and 100 % of the forces generated during walking in corresponding planes.

Results

We present the results [median (range)] from 100 % loading during walking. In axial compression, the PLN was less shortened than the combination with two 4.0-mm TEN [by 4.4 (3.4–5.4) mm vs. 5.2 (4.8–6.6) mm, respectively; p = 0.030]. No difference was found in shortening between the PLN and the four 3.0-mm TEN [by 7.0 (3.3–8.4) mm; p = 0.065]. The two 3.0-mm TEN did not withstand the maximum shortening of 10.0 mm. In external rotation, the PLN rotated 12.0° (7.0–16.4°) while the TEN models displaced more than the maximum of 20.0°. No model withstood a maximal rotation of 20.0° internal rotation. In the four-point bending test, in the coronal and the sagittal plane, all combinations except the two 3.0-mm TEN in extension withstood the maximum angulation of 20.0°.

Conclusions

PLN provides the greatest stability in all planes compared to TEN models with end caps, even though the difference from the two 4.0-mm or four 3.0-mm TEN models was small.     

A concise minimum eight year follow-up of proximally porous-coated tapered titanium femoral stem in primary total hip arthroplasty

Purpose

Our goal was to assess clinical and radiographic outcomes using a second-generation circumferentially proximally porous-coated titanium alloy stem at a minimum of eight years of follow-up.

Methods

Ninety-one hips (80 patients) with Fibre Metal Taper (FMT, Zimmer Inc, Warsaw, IN, USA) femoral stems implanted between May 1998 and April 2002 were followed prospectively and re-evaluated at a minimum of eight years postoperatively. The median patient age was 56 (range 34–78) years, with 40 women and 40 men. Radiographic data and clinical follow-up using Harris Hip Score (HHS) and EuroQol (EQ)-5D outcome measures were evaluated.

Results

Mean follow-up was 9.61 (range 8–12.3) years. At the time of the most recent follow-up, the mean HHS was 85.8 (range 46–100) points, mean EQ-5D Weighted Health State Index was 0.76 (range 0.05-1.00), and mean EQ-5D Visual Analogue Score was 80 (range 24–100). All stems were biologically stable, with all hips having osseous ingrowth. One stem was revised due to early periprosthetic fracture with stem subsidence. No hip had diaphyseal osteolysis.

Conclusions

To our knowledge, the data presented here represent the longest clinical follow-up of this second-generation cementless, proximally porous-coated femoral stem. The stems were found to perform well clinically and radiographically beyond the first five years previously reported in the literature. Patients had high levels of satisfaction and function, and osseous fixation occurred reliably without evidence of distal osteolysis.     

Behaviour of the ultra-short anatomic cementless femoral stem in young and elderly patients

Purpose

The question arises as to whether it is possible to obtain rigid fixation of the ultra-short metaphyseal-fitting anatomic cementless stem without diaphyseal fixation in the elderly as well as younger patients. We investigated whether ultra-short, metaphyseal-fitting anatomic cementless femoral stem would provide similar functional improvements in the younger and elderly patients, radiographically secure implant fixation would be achieved in both groups, the bone content would be preserved in both groups, and complication rates would be similar in both groups.

Methods

A total of 100 patients (114 hips) in the younger patient group and 100 patients (112 hips) in the elderly patient group were included in the study. Their mean age was 43.9 ± 6.11 years (range, 31–65 years) in the younger patient group and 78.9 ± 12.1 years (range, 66–91 years) in the elderly patient group. The mean duration of follow-up was 7.5 years (range, six to nine years) in the younger patient group and 7.6 years (range, six to nine years) in the elderly patient group.

Results

The mean postoperative Harris hip scores (95 points versus 91 points), WOMAC scores (11 points versus 15 points), thigh pain (none in either group), UCLA activity scores (6.5 points versus 4.5 points), and radiographic results were not significantly different between the two groups. No hip in either group had an aseptic loosening. No hip in either group had clicking or squeaking sounds or ceramic fractures.

Conclusion

The cementless ultra-short, metaphyseal-fitting anatomic cementless femoral component provides stable fixation without any need of diaphyseal fixation in both younger and elderly patients. Despite the concern, the poor bone quality in elderly patients did not compromise the stability, and osseointegration of this ultra-short, anatomic cementless femoral stem was achieved in all elderly patients.     

Disability After Deployment Injury: Are Women and Men Service Members Different?

Background

Civilian trauma literature suggests sexual dimorphism in outcomes after trauma. Because women represent an increasing demographic among veterans, the question remains if war trauma outcomes, like civilian trauma outcomes, differ between genders.

Questions/purposes

(1) Do women service members develop different conditions resulting in long-term disability compared with men service members after injuries sustained during deployment? (2) Do women service members have more or less severe disability after deployment injury compared with men service members? (3) Are men or women more likely to return to duty after combat injury?

Methods

The Department of Defense Trauma Registry was queried for women injured during deployment from 2001 to 2011. The subjects were then queried in the Physical Evaluation Board database to determine each subject’s return-to-duty status and what disabling conditions and disability percentages were assigned to those who did not return to duty. Frequency of disabling conditions, disability percentages, and return-to-duty rates for 368 women were compared with a previously published cohort of 450 men service members, 378 of whom had orthopaedic injuries.

Results

Women who were unable to return to duty had a higher frequency of arthritic conditions (58% [48 of 83] of women versus 35% [133 of 378] of men, p = 0.002; relative risk [RR], 1.64; 95% confidence interval [CI], 1.307–2.067) and lower frequencies of general chronic pain (1% [one of 83] of women versus 19% [59 of 378] of men, p < 0.001; RR, 0.08; 95% CI, 0.011–0.549) and neurogenic pain disorders (1% [one of 83] of women versus 7% [27 of 378] of men, p = 0.0410; RR, 0.169; 95% CI, 0.023–1.224). Women had more severely rated posttraumatic stress disorder (PTSD) compared with men (38% ± 23% versus 19% ± 17%). Forty-eight percent (64 of 133) of battle-injured women were unable to return to active duty, resulting in a lower return-to-duty rate compared with men (34% [450 of 1333]; p = 0.003).

Conclusions

After deployment-related injury, women have higher rates of arthritis, lower rates of pain disorders, and more severely rated PTSD compared with men. Women are unable to return to duty more often than men injured in combat. These results suggest some difference between men’s and women’s outcomes after deployment injury, important information for military and Veterans Administration providers seeking to minimize postdeployment disability.

Level of Evidence

Level III, prognostic study.