Salphage: Salvage Bacteriophage Therapy for Recalcitrant MRSA Prosthetic Joint Infection

Prosthetic joint infections are a devastating complication of joint replacement surgery. Consequently, novel therapeutics are needed to thwart the significant morbidity and enormous financial ramifications that are associated with conventional treatments. One such promising adjuvant therapeutic is bacteriophage therapy given its antibiofilm activity and its ability to self-replicate. Herein we discuss the case of a 70-year-old female who had a recalcitrant MRSA prosthetic knee and femoral lateral plate infection who was successfully treated with adjuvant bacteriophage therapy. Moreover, this case discusses the importance of propagating bacteriophage therapeutics on bacteria that are devoid of toxins and the need to ensure bacteriophage activity to all bacterial morphologies. Overall, this case reinforces the potential benefit of using personalized bacteriophage therapy for recalcitrant prosthetic joint infections, but more translational research is needed to thereby devise effective, reproducible clinical trials.

Osteochondroma Pathogenesis: Mouse Models and Mechanistic Insights into Interactions with Retinoid Signaling

Osteochondromas are cartilage-capped tumors that arise near growing physes and are the most common benign bone tumor in children. Osteochondromas can lead to skeletal deformity, pain, loss of motion, and neurovascular compression. Currently, surgery is the only available treatment for symptomatic osteochondromas. Osteochondroma mouse models have been developed to understand the pathology and the origin of osteochondromas and develop therapeutic drugs. Several cartilage regulatory pathways have been implicated in the development of osteochondromas, such as bone morphogenetic protein, hedgehog, and WNT/β-catenin signaling. Retinoic acid receptor-γ is an important regulator of endochondral bone formation. Selective agonists for retinoic acid receptor-γ, such as palovarotene, have been investigated as drugs for inhibition of ectopic endochondral ossification, including osteochondromas. This review discusses the signaling pathways involved in osteochondroma pathogenesis and their possible interactions with the retinoid pathway.

Beyond the dermis-high-risk invasive squamous cell carcinoma: a retrospective review

OBJECTIVE

Most cutaneous squamous cell carcinomas (cSCC) are low risk and can be treated with simple excision or ablation. High-risk cSCC require invasive treatment, including radical surgery. We present our experience in treating invasive cSCC of the pelvis and extremities.

METHOD

A retrospective review of the data of patients with invasive cSCC, indicated for surgery between 2014 and 2018, from a single institution was carried out.

RESULTS

A total of 19 patients (nine men, 10 women) were included in the study. Mean age was 62 years; mean tumour size was 8.6cm). Of the 19 patients, five patients with paraplegia with cSCC arising from hard-to-heal ulcers died of infection or bleeding after surgery or systemic therapy. Also, nine patients with localised cSCC underwent margin-negative resection with or without radiation; one patient experienced disease relapse. Of the participants, two patients with previous transplants and multifocal aggressive cSCC underwent numerous resections but succumbed to disease, and two patients who presented with locally recurrent disease after previous positive margin resection and radiation underwent re-resection but developed recurrent disease.

CONCLUSIONS

Prognosis for invasive cSCC largely depends on clinical setting. Tumours arising from ulcers in patients with paraplegia have a poor prognosis regardless of treatment. Invasive cSCC in transplant patients are often multifocal and often recur. Debulking procedures are associated with local recurrence despite radiation. Patients presenting with localised disease have a favourable prognosis with wide resection, flap coverage and adjuvant therapy.

Potential Use of Adjuvant Bacteriophage Therapy With Debridement, Antibiotics, and Implant Retention Surgery to Treat Chronic Prosthetic Joint Infections

The number of arthroplasties conducted annually continues to increase; however, approximately 1%–2% of all knee and hip arthroplasties will become infected. These prosthetic joint infections are costly, difficult to treat, and cause significant morbidity and mortality as a direct result of conventional surgical and medical managements. In this perspective, we discuss factors that make these infections arduous to treat as well as the potential use of adjuvant bacteriophage therapy with debridement, antibiotics, and implant retention surgery to cure these infections without removing the infected prosthesis. We also provide rationale as to why future clinical trials evaluating this novel therapeutic will need to be designed as noninferiority trials, and we compare this approach to 2-stage revision surgery. If bacteriophage therapy continues to show effectiveness, this could revolutionize the treatment of prosthetic joint infections and pioneer new treatments for similar infections.

Successful Treatment of a Recalcitrant Staphylococcus epidermidis Prosthetic Knee Infection with Intraoperative Bacteriophage Therapy

Here, we present a case of a 79-year-old female with a recalcitrant Staphylococcal epidermidis prosthetic knee infection that was successfully treated with a single dose of adjuvant intra-articular bacteriophage therapy after debridement and implant retention surgery. The bacteriophage used in this case, PM448, is the first ɛ² bacteriophage to be used in vivo. Currently the patient is without evidence of clinical recurrence and, interestingly, the patient had also suffered from debilitating aplastic anemia for over 2 years, which is recovering since receiving adjuvant bacteriophage therapy.

Spatially Fractionated Radiotherapy (GRID) Prior to Standard Neoadjuvant Conventionally Fractionated Radiotherapy for Bulky, High-Risk Soft Tissue and Osteosarcomas: Feasibility, Safety, and Promising Pathologic Response Rates

Spatially fractionated radiotherapy (GRID) has been utilized primarily in the palliative and definitive treatment of bulky tumors. Delivered in the modern era primarily with megavoltage photon therapy, this technique offers the promise of safe dose escalation with potential immunogenic, bystander and microvasculature effects that can augment a conventionally fractionated course of radiotherapy. At the University of Maryland, an institutional standard has arisen to incorporate a single fraction of GRID radiation in large (>8 cm), high-risk soft tissue and osteosarcomas prior to a standard fractionated course. Herein, we report on the excellent pathologic responses and apparent safety of this regimen in 26 consecutive patients.

Total Intravenous Anesthesia and Acute Normovolemic Hemodilution for Sarcoma Surgery

Despite optimal local control for high-risk soft tissue sarcomas (STS) with radiation and surgery, there are no other interventions that clearly and significantly reduce the risk of distant relapse after resection. Cytotoxic chemotherapy for localized STS is controversial and is associated with significant side effects. There are significant biologic perturbations that occur at the time of operation and numerous studies have demonstrated that surgical removal of the primary tumor can accelerate the growth of subclinical metastases. While the exact etiology of this phenomenon is unknown, there is some evidence to suggest that allogeneic blood transfusion and volatile inhaled anesthetics may be associated with tumor-promoting processes. At our institution, we have utilized acute normovolemic hemodilution and total intravenous propofol-based anesthesia to avoid these potentially detrimental factors. 

Hyperprogression of Liver Metastasis With Neoadjuvant Immunotherapy for Soft Tissue Sarcoma

Hyperprogression associated with immunotherapy has been reported previously with melanoma, non-small cell lung cancer (NSCLC), renal, and urothelial cancers but not with sarcoma. A 63-year old man with a biopsy-proven, localized 13 cm high-grade myxoid/round cell liposarcoma of the thigh was treated with concurrent, neoadjuvant checkpoint inhibitor immunotherapy and radiotherapy. After his subsequent wide surgical resection, he developed small hepatic lesions that rapidly progressed and caused his death, raising the possibility of hyperprogression in this entity.

Selective Agonists of Nuclear Retinoic Acid Receptor Gamma Inhibit Growth of HCS-2/8 Chondrosarcoma Cells

Chondrosarcoma is the second most common primary bone sarcoma. Treatment of chondrosarcoma is limited to surgery due to radiation and chemotherapy resistance of this cancer. An ideal treatment for chondrosarcoma would be a well-tolerated, minimally invasive local or systemic treatment modality to halt or slow tumor growth prior to resection of local, unresectable local, or metastatic disease. Palovarotene, an agonist of nuclear retinoic acid receptor γ (RARγ) has shown therapeutic action for treatment of heterotopic ossification and osteochondroma without serious adverse effects in animal models. We hypothesized that selective agonists of RARγ would have an inhibitory effect on chondrosarcoma. All human chondrosarcoma specimens expressed RARγ as determined by immunohistochemical staining. The ΗCS-2/8 chondrosarcoma cell line, established from low-grade human chondrosarcoma, was used to examine the actions of RARγ agonists. In ΗCS2/8 pellet cultures, RARγ agonist treatment reduced the mass size and significantly decreased total glycosaminoglycan, protein amounts, and gene expression levels of cartilage matrix molecules when compared with control groups. Systemic treatment with RARγ agonists significantly inhibited the growth of ΗCS-2/8 cell transplants in vivo. Furthermore, local injection of RARγ agonist-loaded poly-lactic acid nanoparticles induced regression of the mass size of the transplants. Histologic analysis demonstrated that RARγ agonist treatment inhibited cell proliferation activity and stimulated encapsulation of the tumor. These findings indicate that RARγ agonists, including palovarotene, may have an anti-tumor effect on low-grade chondrosarcomas. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 38:1045-1051, 2020.

Malignant Transformation of Synovial Chondromatosis: A Systematic Review

Background:

Synovial chondromatosis (SCh) can undergo malignant transformation. Pathologic diagnosis of secondary synovial chondrosarcoma (SChS) is challenging and misdiagnosis may result in over- or undertreatment.

Method:

A systematic review revealed 48 cases of SChS published in 27 reports since 1957. Data was collected to identify findings indicative of SChS and outcomes of treatment.

Results:

At median follow-up of 18 months, patients were reported as alive (10%), alive without disease (22%), alive with disease (15%), dead of disease (19%), dead of pulmonary embolism (4%), and unknown (29%). Initial diagnosis of SChS (grade: low/unknown 48%, intermediate/high 52%) was after biopsy in 58%, local resection in 29%, and amputation in 13%. Seventy-four percent of patients underwent 1.8 (mean) resections. Patients treated prior to 1992 were managed with amputation in 79% of cases compared to 48% after 1992. Symptoms were present for 72 mos prior to diagnosis of SChS.

Synovial chondrosarcoma demonstrated symptom progression over several months (82%), rapid recurrence after complete resection (30%), and medullary canal invasion (43%). The SChS tumor dimensions were seldom quantified.

Conclusion:

Malignant degeneration of synovial chondromatosis is rare but can necessitate morbid surgery or result in death. Pathognomonic signs for SChS including intramedullary infiltration are present in the minority of cases. Progression of symptoms, quick local recurrence, and muscle infiltration are more suggestive of SChS. Periarticular cortical erosion, extra-capsular extension, and metaplastic chondroid features are non-specific. Although poorly documented for SChS, tumor size is a strong indicator of malignancy.

Biopsy and partial resection are prone to diagnostic error. Surgical decisions are frequently based on size and clinical appearance and may be in conflict with pathologic diagnosis.

Cortical Fenestration for Megaprosthesis Stem Revision

Background:

The most common modes of failure for megaprostheses are aseptic loosening followed by periprosthetic infection and stem fracture. Surgical technique for bone and implant exposure is controversial and may influence the success of revision and the need for additional future revisions. The purpose of this study was to evaluate the effectiveness of cortical fenestration for megaprosthesis revision, particularly for stem fracture.

Methods:

From 1985-2014, 196 adult and pediatric patients underwent limb salvage with a distal femoral or proximal tibial megaprosthesis (109 cemented, 87 pressfit). A retrospective chart review was performed to assess the rate of revision based on cemented or pressfit fixation and the use of a cortical window to extract the failed stem.

Results:

27% (29 of 109) of cemented and 18% (16 of 87) of pressfit implants were revised for stem failure. The reasons for revision in the cemented group were loosening (62%), infection (24%), and stem fracture (13%). In the pressfit group, the reasons were loosening (43%), infection (31%), stem fracture (6%), limb-length discrepancy (6%), malrotation (6%), and local recurrence (6%). A cortical window was used in 10 of 45 initial revisions (7 cemented, 3 pressfit) including all of the stem fractures, and in 2 of 15 subsequent re-revisions.

Conclusion:

Cortical fenestration is an effective, bone-preserving method of implant extraction, particularly for broken or cemented stems. It is associated with low rates of loosening and no increase in periprosthetic fractures.

Allograft Reconstruction for Sarcomas of the Tibia

Background:

Allograft reconstruction of oncologic resections involving the tibia can have unpredictable results. Prior studies have reported a high rate of complications and a long recovery period involving prolonged bracing, repeated procedures and extended periods of antibiotics.

Methods:

The case details of 30 tibial allografts (12 adults, 18 children; 20 intercalary, 7 hemicortical, 3 other) were reviewed retrospectively. Based on factors including function, pain, healing and infection, clinical outcomes were stratified into three categories: excellent, moderate, and poor.

Results:

The overall survival rate of the allografts was 66% at a mean follow-up of 42 mos (adults) and 63 mos (children). Healing for metaphyseal junctions was successful in 73% at a mean of 44 weeks and for diaphyseal junctions, 64% at 41 weeks. Intercalary allografts in adults (4 of 20) all became infected and none had excellent results. All hemicortical allografts were performed in adults and 6 of 7 had excellent results. Distal intercalary allografts in children (6 of 20) had either excellent or moderate results with no infections, but had 3 nonunions and 2 fractures. Proximal intercalary allografts in children (8 of 20) had 2 excellent results, but had 6 infections requiring a cement spacer. Five of the six spacers were ultimately revised to another allograft or an arthroplasty.

Conclusion:

For tibial allograft reconstruction, surgeons and patients should prepare for a prolonged treatment course that may include multiple complications and surgeries. Excellent or moderate results can be achieved eventually in most, but amputation may be necessary in 15-20% of cases.

What is the Optimal Reconstruction Option after the Resection of Proximal Humeral Tumors? A Systematic Review

Purpose:

The proximal humerus is a common location for both primary and metastatic bone tumors. There are numerous reconstruction options after surgical resection. There is no consensus on the ideal method of reconstruction.

Methods:

A systematic review was performed with a focus on the surgical reconstructive options for lesions involving the proximal humerus.

Results:

A total of 50 articles and 1227 patients were included for analysis. Reoperation rates were autograft arthrodesis (11%), megaprosthesis (10%), RSA (17%), hemiarthroplasty (26%), and osteoarticular allograft (34%). Mechanical failure rates, including prosthetic loosening, fracture, and dislocation, were highest in allograft-containing constructs (APC, osteoarticular allograft, arthrodesis) followed by arthroplasty (hemiarthroplasty, RSA, megaprosthesis) and lowest for autografts (vascularized fibula, autograft arthrodesis). Infections involving RSA (9%) were higher than hemiarthroplasty (0%) and megaprosthesis (4%).

Postoperative function as measured by MSTS score were similar amongst all prosthetic options, ranging from 66% to 74%, and claviculo pro humeri (CPH) was slightly better (83%). Patients were generally limited to active abduction of approximately 45° and no greater than 90°. With resection of the rotator cuff, deltoid muscle or axillary nerve, function and stability were compromised even further. If the rotator cuff was sacrificed but the deltoid and axillary nerve preserved, active forward flexion and abduction were superior with RSA.

Discussion:

Various reconstruction techniques for the proximal humerus lead to relatively similar functional results. Surgical choice should be tailored to anatomic defect and functional requirements.

Increased Femoral Component Size Options Improves Manipulation Rate in Females and Knee Society Clinical Scores in Males

INTRODUCTION

The gender-specific total knee arthroplasty (TKA) debate focuses on differences in distal femoral mediolateral to anteroposterior aspect ratio between males and females. However, randomized studies have been unable to demonstrate significant differences in outcomes utilizing gender-specific implants. No studies have examined the effect of intermediate femoral component sizes on outcome. We compared outcomes before and after intermediate sizing availability.

MATERIALS AND METHODS

We identified 331 patients (413 knees) who underwent primary TKA between 2003 and 2004 with a single complete knee system. There were 121 males and 210 females. Three intermediate femoral sizes were added in March 2004 to the six initial options. Patients before March 2004 were assigned to group 1 (n=178), and after to group 2 (n=235).

RESULTS

Follow-up averaged 8.5 years. Preoperative demographics and clinical scores were similar between groups. Knee Society (KS) clinical and functional scores improved in females in both groups, but there was no significant difference. Male patients in group 2 had a significant improvement in KS clinical scores compared to male patients in group 1 (group 1: 33.9, group 2: 41.1; p=0.01). Females in group 2 had significantly less need for manipulation, 1.9%, versus females in group 1, 8.7% (p=0.01). MUA rates were similar for men between groups. Overall, there were 19 revisions (4.6%) with no differences between groups or by genders. Once intermediate sizes were available, they were used in 48% of females and 13% of males. The average femoral component size for females in group 1 was 65 mm and decreased in group 2 to 62.5 mm. The average size of femoral components in males was 70 mm in both groups.

CONCLUSIONS

Availability of intermediate size femoral component sizes was associated with a lower rate of manipulation in female patients. Greater KS clinical score improvement was observed in men after availability of additional femoral sizes.

The effect of surgery with radiation on pelvic Ewing sarcoma survival

BACKGROUND

Pelvic Ewing sarcoma (ES) has poorer outcomes than extremity-based lesions and the method of local control is controversial.

METHODS

A retrospective review was performed of 40 primary pelvic or sacral ES treated by a single surgeon. All received modern chemotherapy and those that received radiation were treated with modern dosages.

RESULTS

Fifty-five percent were disease-free at latest follow-up (median, 83.1 mos). Sixty-one percent had ≥ 99% necrosis, which was associated with 65% disease-free survival. Larger size (P = 0.016) and the absence of metastatic disease (P = 0.005) was predictive of survival. Eighty-three percent of relapsed patients were DOD. Half of patients who received surgery alone or RT alone have NED while 57% of those who received S/RT have NED. Complication rates were 69% (S/RT), 75% (surgery alone), 10% (RT alone). Functional outcomes were similar.

CONCLUSION

Primary pelvic ES is localized at presentation in 50% and the absence of metastases is the strongest predictor for survival. Chemotherapy is key, but excellent histologic response is neither a guarantee nor a necessity for survival. More than one-third die despite an excellent histologic response and at least one-third with lung metastases survive. With chemotherapy, radiation, and surgery, reasonable control of disease can be achieved.

LEVEL OF EVIDENCE III

Case-control or retrospective cohort study.

Comparison of custom to standard TKA instrumentation with computed tomography

PURPOSE

There is conflicting evidence whether custom instrumentation for total knee arthroplasty (TKA) improves component position compared to standard instrumentation. Studies have relied on long-limb radiographs limited to two-dimensional (2D) analysis and subjected to rotational inaccuracy. We used postoperative computed tomography (CT) to evaluate preoperative three-dimensional templating and CI to facilitate accurate and efficient implantation of TKA femoral and tibial components.

METHODS

We prospectively evaluated a single-surgeon cohort of 78 TKA patients (51 custom, 27 standard) with postoperative CT scans using 3D reconstruction and contour-matching technology to preoperative imaging. Component alignment was measured in coronal, sagittal and axial planes.

RESULTS

Preoperative templating for custom instrumentation was 87 and 79 % accurate for femoral and tibial component size. All custom components were within 1 size except for the tibial component in one patient (2 sizes). Tourniquet time was 5 min longer for custom (30 min) than standard (25 min). In no case was custom instrumentation aborted in favour of standard instrumentation nor was original alignment of custom instrumentation required to be adjusted intraoperatively. There were more outliers greater than 2° from intended alignment with standard instrumentation than custom for both components in all three planes. Custom instrumentation was more accurate in component position for tibial coronal alignment (custom: 1.5° ± 1.2°; standard: 3° ± 1.9°; p = 0.0001) and both tibial (custom: 1.4° ± 1.1°; standard: 16.9° ± 6.8°; p < 0.0001) and femoral (custom: 1.2° ± 0.9°; standard: 3.1° ± 2.1°; p < 0.0001) rotational alignment, and was similar to standard instrumentation in other measurements.

CONCLUSIONS

When evaluated with CT, custom instrumentation performs similar or better to standard instrumentation in component alignment and accurately templates component size. Tourniquet time was mildly increased for custom compared to standard.

The multidisciplinary management of giant cell tumor of bone

Giant cell tumor of bone is a locally aggressive lesion with a predilection for local recurrence, and in a small proportion of patients, metastatic disease can develop. Surgery is the mainstay of management for extremity-based lesions. For tumors located in challenging anatomical locations such as the sacrum and spine however, surgery may be associated with unacceptable functional morbidity. There are limited data regarding other treatment modalities such as radiation therapy, cytotoxic chemotherapy, interferon and bisphosphonates. Serial arterial embolization can be effective in some cases. Recent evidence has demonstrated denosumab to be a promising agent in the treatment of unresectable or metastatic disease.

Caring for the incarcerated: an orthopedic perspective

According to the 1976 Supreme Court case of Estelle v Gamble, the government is required to provide prisoners access to the necessary care for known, serious medical needs. Failure to do so violates the Eighth Amendment prohibiting the imposition of "cruel and unusual punishment." Currently, more than 2.5 million Americans are imprisoned, the highest per capita rate in the world. In the current fiscal climate and with burgeoning health care costs for society as a whole, providing care for prisoners poses both moral and logistical challenges. From an orthopedic standpoint, caring for the incarcerated raises uniquely challenging issues due to the nature of this patient population and their types of musculoskeletal conditions.

Incidence and survival in sarcoma in the United States: a focus on musculoskeletal lesions

BACKGROUND/AIM

The purpose of this study was to analyze the incidence and survival in all sarcomas based on year of diagnosis, anatomical site, grade, stage, and age of patient.

MATERIALS AND METHODS

The Surveillance, Epidemiology, and End Results (SEER) database was queried for the years 1975 to 2009 and included 18 registries across the United States representing 28% of the national population. Incidence rates for 2005-2009 and five-year survival rates for 2000-2004 were calculated for all categories of sarcomas for multiple key variables.

RESULTS

Sarcomas are rare, with most occurring in fewer than 5 per 1,000,000. The most common were leiomyosarcoma, Kaposi sarcoma, malignant fibrous histiocytoma, liposarcoma and fibrosarcoma. Survival was poorer for those with more advanced grade, stage, and age at-diagnosis. Most sarcomas affected the lower extremities, followed by the upper extremities and torso. Pelvic tumors were less common, but generally led lower survival than lesions of the extremities.

CONCLUSION

The epidemiology of sarcomas varies widely by type and other variables. Incidence and survival data provide valuable information for patient counseling and may have implications in understanding the natural history of sarcoma. This study represents the most recently updated comprehensive report on all types of sarcomas in the United States.

Genetic engineering of juvenile human chondrocytes improves scaffold-free mosaic neocartilage grafts

BACKGROUND

Current cartilage transplantation techniques achieve suboptimal restoration and rely on patient donor cells or living grafts of chondrocytes.

PURPOSE

We sought to enhance allogeneic grafts by testing mosaics of genetically engineered and naïve juvenile human chondrocytes (jCh).

METHODS

We obtained specimens from three humans and performed three experiments (two in vitro, one in vivo). We compared neocartilage with and without (1) supplemented serum-free medium (chondrocyte differentiation medium [CDM]), (2) adenoviral BMP-2 (AdBMP-2) transduction, and (3) varying ratios (0.1-1) of transduced and naïve jCh. We compared (4) healing with mosaic grafts with naïve neocartilage or marrow stimulation in immunosuppressed rats. For each of 10 in vitro treatment groups, we had six replicates for each human, and for each of three in vivo treatment groups, we had four replicates for one human. We scored the histology with the semiquantitative Bern score.

RESULTS

AdBMP-2 and naïve neocartilage growth in CDM were histologically superior (Bern score, 5.2 versus 3.7; 8.0 versus 1.8) and size (8.0 versus 6.1; 7.9 versus 2.2 mg) to standard medium. In CDM, AdBMP-2 decreased viability (76% versus 90%), but increased BMP-2 production (619 ng/mL versus 43 pg/mL). Ten percent and 25% AdBMP-2 transduction had Bern scores of 6.8 and 6.5 and viability of 84% and 83%, respectively. Twenty-five percent mosaic grafts provided better healing histologically than marrow stimulation or naive neocartilage.

CONCLUSIONS

Low-level AdBMP-2 and CDM augment neocartilage parameters in vitro and vivo.

CLINICAL RELEVANCE

Genetic augmentation of jCh and creation of mosaic neocartilage may improve graft viability and articular healing compared with naïve neocartilage.

Cam morphology in the human hip

A growing interest exists in the diagnosis and treatment of femoroacetabular impingement. Although cam morphology of the proximal femur may conceptually appear to be a relatively simple topographical aberrancy, it is actually positioned amid a complex developmental, kinematic, and biomechanical region of the human body. The authors introduce a new classification scheme and review the historical and anthropological considerations, biomechanics, and genetic factors involved in cam morphology.

Improved accuracy of alignment with patient-specific positioning guides compared with manual instrumentation in TKA

BACKGROUND

Coronal malalignment occurs frequently in TKA and may affect implant durability and knee function. Designed to improve alignment accuracy and precision, the patient-specific positioning guide is predicated on restoration of the overall mechanical axis and is a multifaceted new tool in achieving traditional goals of TKA.

QUESTIONS/PURPOSES

We compared the effectiveness of patient-specific positioning guides to manual instrumentation with intramedullary femoral and extramedullary tibial guides in restoring the mechanical axis of the extremity and achieving neutral coronal alignment of the femoral and tibial components.

METHODS

We retrospectively reviewed 569 TKAs performed with patient-specific positioning guides and 155 with manual instrumentation by two surgeons using postoperative long-leg radiographs. For all patients, we assessed the zone in which the overall mechanical axis passed through the knee, and for one surgeon's cases (105 patient-specific positioning guide, 55 manual instrumentation), we also measured the hip-knee-ankle angle and the individual component angles with respect to their mechanical axes.

RESULTS

The overall mechanical axis passed through the central third of the knee more often with patient-specific positioning guides (88%) than with manual instrumentation (78%). The overall mean hip-knee-ankle angle for patient-specific positioning guides (180.6°) was similar to manual instrumentation (181.1°), but there were fewer ± 3° hip-knee-ankle angle outliers with patient-specific positioning guides (9%) than with manual instrumentation (22%). The overall mean tibial (89.9° versus 90.4°) and femoral (90.7° versus 91.3°) component angles were closer to neutral with patient-specific positioning guides than with manual instrumentation, but the rate of ± 2° outliers was similar for both the tibia (10% versus 7%) and femur (22% versus 18%).

CONCLUSIONS

Patient-specific positioning guides can assist in achieving a neutral mechanical axis with reduction in outliers.

Stubby stems: good things come in small packages

Standard-length porous-coated tapered femoral stems perform exceedingly well in primary total hip arthroplasty (THA) at long-term follow-up. Nevertheless, there are multiple reasons to strongly consider the relatively new concept of short tapered stems. First, there is already a wide variation in the lengths of "standard" components and the ideal length is unknown. The goal of tapered stems is to load the proximal femur, and shortened stems accomplish this task. Second, while the distal extension may help prevent varus, unlike cemented stems, which are failure-prone with varus alignment, tapered designs are not. Additionally, elimination of the distal extension may reduce potential stress shielding. Third, short stems obviate problems with proximal-distal mismatch, excessive femoral bowing, diaphyseal deformities, and preexisting hardware. Fourth, implantation of smaller components requires less violation of bone and soft tissue, facilitating less invasive surgical approaches and favorable revision settings if necessary. Fifth, in comparison to hip resurfacing and other unconventional short-stem designs, tapered stems are familiar to most orthopedic surgeons and do not incur a steep learning curve. Finally, our early experience with this implant in 1750 THAs since 2006 has been excellent. In a series of >650 THA, compared to standard-length tapered stems, the short stem had equivalent clinical outcome scores, significantly fewer femoral fractures (12/389 [3.1%] vs 1/269 [0.4%]), and only 1 (1/269 [0.4%]) femoral revision (infection) at 2-year follow-up. Short stems represent the logical progression of a proven precedent in standard-length tapered stems.

Neutral mechanical alignment: a requirement for successful TKA: affirms

Restoration of an overall neutral mechanical axis has been a long-held tenet in total knee arthroplasty (TKA). Numerous biomechanical, finite element, and clinical studies have demonstrated that coronal malalignment, particularly varus, is associated with increased strain, higher failure rates, and, in some cases, poorer outcomes. With advances in computer-assisted navigation, 3-dimensional imaging, and patient-specific positioning guides, the potential for greater precision in bone resection and component positioning has rekindled interest in this important issue. Several recently published studies demonstrating no difference in survivorship for malaligned TKAs have challenged the concept of an alignment safe zone. Some surgeons have discussed a paradigm shift in defining optimal alignment. While we agree that compared to several decades ago, there is greater understanding of TKA kinematics and that broad targets for alignment may not impart significant benefit as a dichotomous variable, there are multiple reasons why neutral alignment and classic bone cuts remain valid and important in delivering a successful TKA. In comparison to the preponderance of evidence advocating a neutral mechanical axis and approximately 5° to 7° valgus anatomic alignment, there is insufficient support for reasonably choosing any other target. Although technology has improved surgical precision, it has not eliminated the human factor, and aiming for neutral provides the safest margin for error. The foremost objective of TKA is a durable and well-functioning joint, not necessarily one that replicates normal or the patient's native condition. While the latter goal is certainly desirable, the priority of the former should never be overlooked.

Nonoperative management of a sagittal coracoid fracture with a concomitant acromioclavicular joint separation

Separation of the acromioclavicular joint in conjunction with a coracoid fracture is a rare injury. Treatment decisions are traditionally based on the level of the fracture, the status of the coracoclavicular ligament and the activity level of the patient. We present a novel coracoid fracture pattern treated nonoperatively in a young, active patient and a thorough review of the literature regarding this topic.

Improving function in transtibial amputation: the distal tibiofibular bone-bridge with Arthrex Tightrope fixation

The distal tibiofibular bone bridge for transtibial amputation is designed to allow for axial loading in a prosthesis, better proprioception of the residual limb, and less pain from tibiofibular instability. Originally described as an osteoperiosteal sleeve by Janos Ertl, Sr. in the early 20th century, it was later modified by Pinto and Harris to a fibular bone block technique. In this article, we describe a new technique for securing the fibular bone block. Use of the Tightrope (Arthrex, Naples, Florida) suture-button fixation system minimizes the chance of symptomatic hardware, prevents diastasis, and allows physiologic micromotion. In our experience, this procedure has been highly successful.

Periprosthetic femoral condyle fracture after total knee arthroplasty and saline-coupled bipolar sealing technology

Saline-cooled bipolar radiofrequency technology has emerged as an effective method to reduce bleeding during total knee arthroplasty (TKA). No significant osseous complications have been previously reported, and animal studies have revealed no difference in bone healing, strength, or osteonecrosis compared to conventional monopolar electrocautery. This article presents 4 cases of early postoperative periprosthetic femoral condyle fractures after extensive use of saline-cooled bipolar radiofrequency requiring revision TKA. Preoperative, intraoperative, and postoperative details from 4 patients who underwent early TKA revision for periprosthetic femoral condyle fractures were retrospectively reviewed. The senior author (M.M.) had not experienced similar condyle fractures postoperatively in over 2,500 primary TKAs performed over 2 decades. The cases described here were performed between July 2009 and November 2009, shortly after increasing the usage of saline-cooled bipolar radiofrequency on the synovium overlying the femoral condyles for hemostasis. No other change in surgical technique or implant that occurred during this time was observed. The senior author has significantly decreased his use of saline-cooled bipolar radiofrequency and has seen no recurrence of these complications.

Efficacy of surgery for femoroacetabular impingement: a systematic review

BACKGROUND

Recent case studies on the surgical treatment of femoroacetabular impingement (FAI) have introduced a large amount of clinical data. However, there has been no clear consensus on its efficacy.

HYPOTHESIS

The current literature can be clarified to address 4 questions: (1) Does treatment for FAI succeed in improving symptoms? (2) In which subset of patients should treatment for FAI be avoided? (3) Is labral refixation superior to simple resection? (4) Does treatment for FAI alter the natural progression of osteoarthritis in this group of typically young patients?

STUDY DESIGN

Systematic review.

METHODS

Twenty-three reports of case studies on the surgical treatment of FAI were identified and a systematic review was conducted. Data from each study were collected to answer each of the 4 focus questions.

RESULTS

This review of 970 cases included 1 level II evidence trial, 2 level III studies, and 20 level IV studies. Based on patient outcome scores and effect size, all studies demonstrated improvement of patient symptoms. Up to 30% of patients will eventually require total hip arthroplasty; those patients with Outerbridge grade III or IV cartilage damage seen intraoperatively or with preoperative radiographs showing greater than Tonnis grade I osteoarthritis will have worse outcomes with treatment for FAI. Only 2 studies directly compared labral refixation with labral debridement. Several studies reported postoperative osteoarthritis findings; only a minority of these patients had progression of their osteoarthritis.

CONCLUSION

Surgical treatment for FAI reliably improves patient symptoms in the majority of patients without advanced osteoarthritis or chondral damage. Early evidence supports labral refixation. It is too soon to predict whether progression of osteoarthritis is delayed.

CLINICAL RELEVANCE

These results may be used to help predict the outcome of surgical treatment of FAI in different patient populations and to assess the need for labral refixation.

Fine needle aspiration for clinical triage of extremity soft tissue masses

BACKGROUND

Fine needle aspiration cytology (FNAC) is a rapid and low-morbid alternative to open biopsy or needle core biopsy for soft tissue masses. Numerous reports describe its use with metastatic or recurrent lesions, but FNAC is less accepted for primary lesions.

QUESTIONS/PURPOSES

We wished (1) to estimate the sensitivity, specificity, and positive and negative predictive values of FNAC for diagnosing malignancy; (2) to estimate the accuracy of subtyping and grading.

METHODS

We retrospectively examined the diagnostic accuracy and clinical effectiveness of office-based FNAC performed by a trained pathologist on 213 females and 219 males (mean age, 51.8 years) who presented with a palpable soft tissue mass to one musculoskeletal oncology clinic between 2002 and 2008.

RESULTS

The FNAC was reported as benign in 62.0%, indeterminate in 8.1%, and malignant in 29.9%. A second technique, such as needle core biopsy or open biopsy, was performed for 24.8% of lesions before a definitive treatment plan was rendered. Final tissue confirmation by open biopsy or resection was available for 52.2% of benign FNAC and 78.3% of malignant FNAC. Sensitivity, specificity, and positive and negative predictive values for detecting malignancy with either histopathologic confirmation or clinical followup were 89.2%, 89.8%, 96.1%, and 98.1%. There were seven sampling and nine interpretation FNAC errors in determining the nature of the lesion. Subtyping and grading for malignant lesions were 77.2% and 95.2% accurate, respectively.

CONCLUSIONS

FNAC is effective for initial triage and treatment selection at tertiary referral centers with close collaboration among the surgeon, pathologist, and radiologist.

LEVEL OF EVIDENCE

Level II, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Calcium phosphate cement to prevent collapse in avascular necrosis of the femoral head

Subchondral and articular collapse following nontraumatic osteonecrosis of the femoral head is an important cause of osteoarthritis in patients between ages 20 and 40. Because hip arthroplasty in the younger population is prone to early wear and failure, it is paramount to prevent collapse once osteonecrosis is detected. Natural remodeling of the osteonecrotic areas by adjacent normal bone is predominated by osteoclastic resorption, which weakens the cancellous bone and allows microfractures to occur before full healing can take place. Current treatment modalities include core decompression and various adjuncts such as bone graft, mesenchymal stem cells and tantalum implants to provide structural integrity and to speed bony creeping substitution. Calcium phosphate cement has been reported in the treatment of fractures, especially depressed tibial plateau fractures. It is slow to resorb and is gradually replaced by bone, allowing prolonged support of periarticular fractures during healing. We hypothesize that calcium phosphate cement in conjunction with standard decompression of osteonecrotic femoral head lesions can prevent collapse.

Volumetric Cine CMR to Quantify Atrial Structure and Function in Patients with Atrial Dysrhythmias

PURPOSE

To implement a cardiac magnetic resonance (CMR)-based protocol to define atrial structure and function in individuals with paroxysmal atrial fibrillation (PAF), heritable cardiac conduction and myocardial disease with atrial dysrhtyhmias (HCCMD), and healthy controls.

METHODS

Fifteen controls, 20 PAF, and 12 HCCMD subjects underwent CMR examination including: multislice short-axis cine, multislice horizontal long-axis cine, and gadolinium-enhanced coronal plane magnetic resonance angiography (MRA) for pulmonary vein analysis. We also assessed for ventricular myopathy with delayed myocardial enhancement (DME) acquisitions.

RESULTS

Right and left ventricular measurements did not differ among the three groups. Seven heritable atrial dysrhythmia subjects and no control or PAF subjects demonstrated midmyocardial fibrosis of the basal interventricular septum by DME. Left atrial (LA) volume at the onset of atrial systole and minimal LA volume were significantly higher in PAF subjects compared to controls (p < 0.05 for both), LA percent emptying was significantly lower in PAF subjects (p < 0.01), and RA percent emptying was significantly lower in PAF subjects compared to controls (p < 0.01), though these differences were not significant when controlling for heart rate, age and gender. There was no significant difference in right atrial (RA) volumes among study groups. Atrial volumes and function did not differ significantly between heritable atrial dysrhtyhmia subjects and controls. PAF subjects had greater frequency of a right middle pulmonary vein (RMPV) than controls (6/20 vs. 3/15) that did not reach statistical significance.

CONCLUSIONS

CMR can quantify atrial structure and function in patients with PAF compared to controls. This protocol could not detect abnormalities in atrial function in early affected patients with heritable cardiomyopathy and atrial premature beats.