Grand Rounds from HSS: Management of Complex Cases

November 2023 | Volume 12, Issue 3 | Rheumatology Issue

The Collaborative Nature of Rheumatology

Karmela Kim Chan, MD

As the 4 cases in this issue on rheumatology demonstrate, the complex constellation of a patient’s presenting signs and symptoms often indicates the need for an interdisciplinary approach.

In Case 1 from Genna Braverman, MD, Andrew D. Schweitzer, MD, and Arthur M.F. Yee, MD, PhD, a 31-year-old man with a history of uveitis is diagnosed with sarcoidosis after presenting with facial palsy and diabetes insipidus; treatment is directed at organ-specific manifestations in coordination with systemic immunomodulatory approaches.

In Case 2 from Romy Kallas, MD, and Eli L. Diamond, MD, a 65-year-old woman with acute onset of shortness of breath, pericardial tamponade, and soft-tissue thickening in the retroperitoneum is diagnosed with Erdheim–Chester disease. Belatedly, biopsy of the easily accessible xanthelasma allowed for identification of a targetable mutation.

In Case 3 from Brandon J. Blau, MD, and Anne R. Bass, MD, a 67-year-old woman with chronic lymphocytic leukemia and iatrogenic hypogammaglobulinemia is hospitalized for evaluation of fever of unknown origin. When bacterial, acid-fast bacilli, and fungal cultures are all negative, testing of respiratory and cerebrospinal fluids detects the presence of enterovirus RNA.

And in Case 4 from Megan A. Crippen, MD, Caitlin A. Ensor, MD, MS, and Sarah F. Taber, MD, a 17-year-old boy, who presents with gastrointestinal complaints, sensory and motor deficits, and peripheral eosinophilia, is found to have eosinophilic granulomatosis with polyangiitis and develops numerous complications.

As always we welcome your feedback. Drop us an email at complexcases@hss.edu.

Cases in this Issue

• Polyuria in a 31-Year-Old Man with Uveitis, Rash, and Periarthritis: An Application of Occam’s Razor
• Erdheim–Chester Disease in a 65-Year-Old Woman Presenting with Retroperitoneal Soft-Tissue Infiltration
• Chronic Enterovirus Infection Manifesting as Diffuse Myalgias and Arthralgias in a 67-Year-Old Woman Receiving Obinutuzumab
• A Case of Eosinophilic Granulomatosis with Polyangiitis in a 17-Year-Old Boy

August 2023 | Volume 12, Issue 2 | Orthopaedic Surgery Issue

The Use of Robotic-Assisted Surgery in Managing Complex Spinal Deformity

David M. Dines, MD

The spine is a complex structure, providing support to the body and protecting the delicate nerves that allow motion and function. As the body ages, the spine may develop scoliosis or kyphosis, deformities that can cause debilitating pain and disability comparable to cancer or a chronic heart condition. Adult spinal deformity surgery can dramatically improve a patient’s posture and overall quality of life.

HSS draws a number of referrals for complex spinal deformities and revision surgeries. HSS has also been at the forefront of innovation in this field, adopting technology such as computed tomography (CT) guidance and robotic assistance to improve safety and efficacy. HSS also has pioneered surgical protocols to minimize bleeding, reduce opioid use, and maximize recovery after spinal fusion.

This issue features 3 clinical cases highlighting the utility of robotic-assisted spine surgery. In Case 1, Jerry Du, MD, and Matthew E. Cunningham, MD, PhD, detail the use of intraoperative 3D fluoroscopy-guided navigation to safely treat a man whose congenital scoliosis exhibited a challenging 135° thoracic curve. In Case 2, Austin C. Kaidi, MD, MSc, and Sheeraz A. Qureshi, MD, MBA, discuss the use of minimally invasive lumbar decompression and fusion in the treatment of a man with isthmic spondylolisthesis. In Case 3, Karim Shafi, MD, Francis C. Lovecchio, MD, and James E. Dowdell III, MD, present the use of optical navigation, accessory rods, and proximal ligamentous augmentation to address severe coronal malalignment in an older patient who, years earlier, had undergone abdominal surgery for a visceral infection.

We welcome your input; please send us a note at complexcases@hss.edu.

Cases in this Issue

• Correction of Severe Congenital Scoliosis in a 28-Year-Old Man
• Robotic-Assisted Minimally Invasive Lumbar Decompression and Fusion for Isthmic Spondylolisthesis in a 41-Year-Old Man
• The Use of Novel Technologies in Coronal Plane Correction in a 72-Year-Old Man

March 2023 | Volume 12, Issue 1 | Orthopaedic Surgery Issue

Contemporary Clinical Challenges in Orthopaedic Trauma

David M. Dines, MD, and William M. Ricci, MD

In this issue of Grand Rounds from HSS: Management of Complex Cases, we present 3 cases that provide valuable information on the management of complex orthopaedic trauma.

In Case 1, William M. Ricci, MD, and Gregory S. DiFelice, MD, discuss the care of a 37-year-old who sustained a high-energy proximal tibia fracture and substantial injury to the knee ligaments after a skiing accident. Dr. Ricci made use of a fragment-specific approach to fracture fixation, and Dr. DiFelice used a unique open approach to repair the posterior cruciate ligament complex and lateral meniscus.

In Case 2, Aleksey Dvorzhinskiy, MD, MSc, and William M. Ricci, MD, introduce a patient with periprosthetic humeral fracture after shoulder arthroplasty. As the number of shoulder arthroplasties performed continues to increase, so too will the numbers of such complications. The authors present an excellent overview of the issues faced in these complex situations.

In Case 3, Daniel Dziadosz, MD, presents a case demonstrating the complexities surrounding chronic osteomyelitis in the surgical treatment of an intertrochanteric femur fracture—an uncommon complication that can be extremely difficult to treat. The goals for this patient were to manage infection while promoting fracture healing.

We hope these case presentations provide insight to clinicians treating patients with comparable complex traumas. We welcome your feedback; contact us at complexcases@hss.edu.

Cases in this Issue

• Managing High-Energy, Proximal Tibia and Fibula Fracture in a 37-Year-Old After a Skiing Accident
• Obtaining Adequate Fixation in a Periprosthetic Humerus Fracture Around a Shoulder Arthroplasty Stem in an 81-Year-Old Man
• Osteomyelitis Requiring Open Debridement After Intertrochanteric Femur Fracture in a 62-Year-Old Man

November 2022 | Volume 11, Issue 3 | Rheumatology Issue

Expecting the Unexpected in Rheumatology

Karmela Kim Chan, MD

It is my honor to present our annual rheumatology issue, 4 cases that highlight the vital importance of curiosity when a patient’s clinical course does not fit neatly into a physician’s expectations. They also illustrate how often rheumatologic care is a team endeavor, requiring multidisciplinary expertise.

In Case 1 from Jheel Pandya, MD, and Sarah Faith Taber, MD, a 4-year-old presents with a diagnosis of anti-synthetase syndrome, only for the diagnosis to be revised when an observant clinician notices that the child’s mother has the same unusual rash.

In Case 2 from Caroline H. Siegel, MD, MS, and Lisa R. Sammaritano, MD, a woman with recurrent amaurosis fugax and antiphospholipid antibodies, and prior late pregnancy loss, carries a pregnancy to term with anticoagulation and a tumor necrosis factor-alpha inhibitor.

In Case 3 from Jeong Min (April) Yu, MD, David Pisapia, MD, and Kyriakos A. Kirou, MD, DSc, FACP, a presumed diagnosis of neurosarcoidosis is upended when the patient does not respond to high doses of glucocorticoids.

Finally, in Case 4 from Robert Spandorfer, MD, a patient with longstanding myeloperoxidase-positive vasculitis with seemingly small and large vessel involvement presents with new acute kidney injury and a surprising finding on renal biopsy.

Cases in this Issue

• POIKTMP in a 4-Year-Old with a History of Anti-Synthetase Syndrome
• Recurrent Amaurosis Fugax in a Pregnant Patient with “Triple Positive” Antiphospholipid Antibodies and Prior Late Pregnancy Loss
• Intravascular Lymphoma of the Brain Masquerading as Neurosarcoidosis in a 63-Year-Old Man
• Overlapping ANCA-Associated Vasculitis and IgG4-Related Disease in a 65-Year-Old Man with Acute Renal Failure

Consultants

Andrew D. Schweitzer, MD
Associate Professor of Clinical Radiology
Weill Cornell Medicine

Yaxia Zhang, MD, PhD
Associate Attending Pathologist
Associate Professor of Pathology and Clinical Laboratory Medicine
Weill Cornell Medicine

August 2022 | Volume 11, Issue 2 | Orthopaedic Surgery Issue

Limb Lengthening: Innovation in Motion

David M. Dines, MD, and Austin T. Fragomen, MD

In this issue of Grand Rounds from HSS: Management of Complex Cases, we highlight the field of limb lengthening and complex reconstruction, presenting 3 cases involving application of the latest technologies in limb salvage and prosthetic replacement at HSS.

In Case 1, Taylor J. Reif, MD, and Austin T. Fragomen, MD, discuss limb reconstruction after bone tumor resection and several failed intercalary allograft surgeries in a 54-year-old man. They found that the patient had a femur nonunion with infection in the allograft bone and a 10-cm leg length discrepancy. His surgeons used a magnetic internal lengthening nail in compression mode to heal the nonunion and simultaneously lengthen the femur and tibia using the same implant.

In Case 2, Austin T. Fragomen, MD, and Stephen J. Wallace, MD, report on the care of a 57-year-old man with an infected, hypertrophic nonunion of the tibia and who, after many failed surgeries, was facing transtibial amputation. They highlight the use of circular external fixation with automatic adjusting struts to resolve this limb-threatening condition.

In Case 3, Jason S. Hoellwarth, MD, and S. Robert Rozbruch, MD, present a case involving traumatic above-knee amputation that left the 25-year-old patient with a very short residual femur and prosthetic socket difficulties. His surgeons implanted a prosthetic stem into his femur using osseointegration technology to provide superior function.

Click here for a variety of videos related to the procedures involved in the complex care of these patients.

Cases in this Issue

• Oncologic Allograft Femur Nonunion Treated with the Internal Lengthening and Compression Nail
• Hypertrophic Tibial Nonunion Treated with AutoStrut External Fixation
• Transfemoral Osseointegration for a Patient with a Very Short Residual Femur After Amputation

March 2022 | Volume 11, Issue 1 | Orthopaedic Surgery Issue

The Increasing Complexities of Pediatric Orthopaedics

David M. Dines, MD, and Roger F. Widmann, MD

In this issue of Grand Rounds from HSS: Management of Complex Cases, we present 3 fascinating cases that detail treatments for children with not uncommon yet complex conditions.

In Case 1, Danielle E. Chipman, BS, Nicolas Pascual-Leone, BA, and Daniel W. Green, MD, MS, FACS, present a complicated knee reconstruction for patellar instability in an 8-year-old boy. They outline an approach using several techniques, including medial patellofemoral ligament reconstruction with gracilis allograft, to stabilize the patella and prevent future dislocation.

In Case 2, Peter D. Fabricant, MD, MPH, Nicolas Pascual-Leone, BA, and Samuel A. Taylor, MD, present a multiplanar proximal humeral osteotomy and long head of biceps tendon transfer for a painful humerus deformity in a teenager resulting from physeal injury earlier in life. This procedure relieved pain and increased shoulder range of motion by correcting the proximal humeral deformity. Their success in this case demonstrates the promise of this technique for treating children with humerus deformity, whether secondary to congenital, idiopathic, traumatic, hematologic, or infectious conditions.

Finally, in Case 3, Tyler Uppstrom, MD, Arkady Blyakher, MD, and Roger F. Widmann, MD, present a procedure for treating a 10-year-old with tibial nonunion and multilevel deformity secondary to previous osteomyelitis. Through the use of staged distraction osteogenesis and osteotomy in a ring external fixator with a 6-axis correction system, the surgeons corrected the deformity while permitting early range of motion and weight bearing, with excellent results.

We hope the cases presented in this issue help you in treating patients with similarly challenging pediatrics conditions in your practice.

Cases in this Issue

• Obligatory Patellar Instability in an 8-Year-Old Boy
• Operative Correction of Proximal Humerus Varus and Retroversion Deformity in an Adolescent
• Treating Tibial Nonunion and Multilevel Deformity with Distraction Osteogenesis and Ring Fixator with 6-Axis Correction in a 10-Year-Old Girl

November 2021 | Volume 10, Issue 2 | Rheumatology Issue

The Art and Science of Rheumatology

Karmela Kim Chan, MD

It is my honor to serve as editor of this issue of Grand Rounds from HSS: Management of Complex Cases focused on rheumatology. We at HSS take pride in our thoughtful and thorough approach to caring for patients, and we are excited to share with you lessons we have learned in 4 cases involving complex rheumatologic conditions.

One principle encountered in medical training is that when a diagnosis is elusive, consider the triad of pathologies of malignancy, infection, or rheumatic disease. The cases in this issue confirm that there is a good reason this heuristic endures.

Case 1 from Kevin Yip, MD, and Anne R. Bass, MD, suggests that in a patient with a previously treated hepatitis B virus infection, vaccination against SARS-CoV-2 may have activated the immune system in an unexpected way. Case 2 from Diane Zisa, MD, Roberto A. Garcia, MD, and Susan M. Goodman, MD, demonstrates the challenge of identifying new-onset inflammatory arthritis after total joint arthroplasty. Case 3 from David R. Fernandez, MD, PhD, details the diagnostic curveballs encountered in a patient with proximal muscle weakness, rash, and nailfold capillary changes. Finally, Case 4 from Lauren Robinson, MD, and Sarah Taber, MD, presents a 2-year-old boy with macrophage activation syndrome, whose underlying diagnosis of Kikuchi–Fujimoto disease was revealed several years later.

I hope you find the cases in this issue as stimulating as I did. These cases show the complexities and uncertainties that rheumatologists face routinely as we practice this art form we call medicine.

• Recurrent Leukocytoclastic Vasculitis Following mRNA COVID-19 Vaccination in a 76-Year-Old Woman with Previously Treated Hepatitis B Virus Infection
• Incident Rheumatoid Arthritis in a 64-Year-Old Woman with a Prosthetic Joint
• An Overlap of Drug-Induced Subacute Cutaneous Lupus Erythematosus and Dermatomyositis in an 80-Year-Old Woman
• Kikuchi–Fujimoto Disease in a 6-Year-Old Boy with a History of Macrophage Activation Syndrome

The Management of Glenohumeral Bone Loss in Shoulder Arthroplasty

Michael C. Fu, MD, MHS, and David M. Dines, MD

As the biomechanically complex link between the upper extremity and the rest of the body, the shoulder provides stability, range of motion, and strength for activities of daily living and recreation. Over the past several decades, with an ever more active aging population, the incidence of shoulder arthritis, and consequently of shoulder arthroplasty, has risen. This has naturally led to a large number of innovations in shoulder arthroplasty. When successful, shoulder arthroplasty consistently relieves pain, improves function, and increases patient satisfaction.

With the high volume of primary shoulder arthroplasty performed comes a corresponding rise in the number of complex cases, failures, and revisions. Remarkably, most shoulder replacements in the United States take place at low-volume centers. As the top hospital for orthopaedics in the country, HSS is a referral center for patients needing complex reconstructions and revision surgery. Accordingly, the HSS shoulder service possesses a wealth of experience in addressing difficult shoulder cases.

In this issue, we highlight 3 clinically challenging cases. In Case 1, Ryan C. Rauck, MD, and Lawrence V. Gulotta, MD, describe the use of a convertible metal-backed glenoid component with bone grafting in total shoulder arthroplasty (TSA) for glenohumeral osteoarthritis with significant glenoid deformity. In Case 2, Allen D. Nicholson, MD, and Theodore A. Blaine, MD, highlight the use of a custom 3D-printed titanium implant for glenoid reconstruction in reverse TSA for treating postinfectious glenohumeral arthritis. In Case 3, Ryan S. Selley, MD, and Samuel A. Taylor, MD, explain the use of an allograft–prosthetic composite in reverse TSA of the humeral component in a young patient with a history of proximal humerus malunion, multiple revisions, and a failed reverse TSA in the setting of massive proximal humeral bone loss.

• Addressing Significant Glenoid Deformity in a Younger Patient with Glenohumeral Osteoarthritis
• Treating Massive Glenoid Bone Deficiency with a Custom Metal Glenoid Implant
• Allograft-Prosthetic Composite Proximal Humerus Reconstruction in Reverse Shoulder Arthroplasty for Massive Bone Loss

Solving the Puzzles of Rheumatic Diseases

S. Louis Bridges Jr., MD, PhD

As we send this issue to press in October 2020, clinicians and patients at HSS have transitioned to a “new normal” after the disruptive emergence of COVID-19 earlier this year. During my first few weeks at HSS, I have been deeply impressed by the dedication of our faculty, staff, and trainees to safety amid this unprecedented challenge. Our rheumatology faculty and staff have inspired me by their commitment to improving the lives of patients affected by rheumatic diseases, as demonstrated by the cases presented in this issue.

In Case 1, Caroline H. Siegel, MD, and Doruk Erkan, MD, MPH, discuss the treatment of a man with pain and cyanosis of the digits caused by antiphospholipid syndrome. In Case 2, Diane Zisa, MD, and Kyriakos A. Kirou, MD, DSc, FACP, review the case of a woman with systemic lupus erythematosus whose nephritis and cutaneous vasculitis were refractory to treatment. In Case 3, Kimberly Showalter, MD, MS, Jessica K. Gordon, MD, MS, and Bella Mehta, MBBS, MS, present the case of a woman with Sjögren’s syndrome with rapidly progressive interstitial lung disease. And in Case 4, David R. Fernandez, MD, and Linda A. Russell, MD, discuss the progression of a 32-year-old woman’s dermatomyositis—a rash that resolved during pregnancy, only to recur postpartum, along with fatigue and weakness.

• Management of Diffuse Peripheral Ischemia in Antiphospholipid Syndrome: Anticoagulation, Immunosuppression, Vasodilation, or All Three?
• Relapsing Lupus Nephritis and Cutaneous Vasculitis: A Race to Contain B Cells
• Sjögren’s Syndrome-associated Interstitial Lung Disease Treated with Immunosuppression
• The Use of Autoantibody Testing in a Postpartum Patient at Risk of Malignancy-Associated Dermatomyositis

Innovative Options for Patients with Devastating Upper Extremity Injuries

Edward C. Jones, MD, MA

The HSS Center for Brachial Plexus and Traumatic Nerve Injury epitomizes the surgical expertise, collaboration, and multimodal techniques necessary to properly diagnose and treat very complex conditions. The 3 cases presented in this issue highlight teamwork as an essential aspect of ensuring good outcomes for patients with devastating injuries to the brachial plexus and upper extremity.

A meticulous diagnostic process begins with physical examination and the identification of subtle, elusive physical signs. These findings serve to direct a purposeful, multidisciplinary patient evaluation using sophisticated electrodiagnostic testing, nerve-specific high-resolution magnetic resonance imaging (MRI), and ultrasonography. Surgical planning involves collaboration among specialties and in some cases 2 surgical teams operating simultaneously, using multiple approaches.

All 3 cases were authored by Drake G. LeBrun, MD, MPH, Darryl B. Sneag, MD, Joseph H. Feinberg, MD, Ogonna K. Nwawka, MD, Steve K. Lee, MD, and Scott W. Wolfe, MD. In the first case, multiple surgical windows were used for neurolysis and nerve transfer for iatrogenic axillary nerve injury following the arthroscopic repair of a humeral avulsion of the glenohumeral ligament. In the second case, high-resolution MRI was used to pinpoint anterior interosseous fascicles of the median nerve and to guide surgeons in decompressing fascicular constrictions using micro–internal neurolysis to treat anterior interosseous nerve syndrome resulting from Parsonage–Turner syndrome. In the third case, 2 surgical teams used multiple approaches to achieve triple nerve transfer and sural nerve grafting to restore function to a patient with an extensive brachial plexus injury.

• Neurolysis and Nerve Transfer for Iatrogenic Axillary Nerve Injury After Humeral Avulsion of the Glenohumeral Ligament Repair
• Microneurolysis to Treat Anterior Interosseous Nerve Syndrome Resulting from Parsonage–Turner Syndrome
• Triple Nerve Transfer and Long Nerve Grafts Restore Function in a Devastating Brachial Plexus Injury

Diagnostic and Treatment Challenges in Rheumatology

Mary K. Crow, MD

This issue features descriptions of several fascinating and challenging patients successfully managed by our Hospital for Special Surgery rheumatologists. The cases highlight examples of the diagnostic and treatment challenges that our physicians address every day.

Case 1, presented by Halide Ozge Basaran, MD, Samir K. Trehan, MD, and Sarah F. Taber, MD, highlights the diagnosis of a 15-year-old boy with pachydermodactyly, a rare form of fibromatosis that can result from minor mechanical trauma to the fingers.

In Case 2, Nilasha Ghosh, MD, and Anne R. Bass, MD, describe the successful treatment of an 83-year-old woman who had checkpoint inhibitor–associated myositis and myocarditis, the result of her prior immunotherapy with nivolumab.

In Case 3, Pantelis P. Pavlakis, MD, PhD, and David R. Fernandez, MD, PhD, discuss a 56-year-old man whose neuropathy associated with trisulfated heparin disaccharide responded well to IV immunoglobulin treatment.

Case 4, presented by Kimberly Showalter, MD, Xiaoping Wu, MD, MS, and Jessica K. Gordon, MD, MS, features a previously healthy 36-year-old man with progressive shortness of breath and dry cough ultimately diagnosed with antisynthetase syndrome responsive to monthly IV cyclophosphamide for 6 months.

• Pachydermodactyly, a Rare and Benign Digital Fibromatosis, Diagnosed in a 15-Year-Old Boy
• Nivolumab-Associated Myositis and Myocarditis in an 83-Year-Old Woman
• Neuropathy Associated with Trisulfated Heparin Disaccharide Antibodies Responsive to IV Immunoglobulin Treatment
• Progressive Dyspnea and Cough in a Healthy, Young Man

From the Editor

Edward C. Jones, MD, MA

The foot and ankle, our weight-bearing pedestal, are also one of the most common sources of functional limitation, intractable pain, and progressive disability. The congruous interaction of so many essential structures in the foot and ankle provides balanced support for a range of activities, from walking to running to vigorous sports—remarkable, when you consider the foot and ankle may repeatedly bear up to five times body weight while walking and up to 13 times body weight during activities such as running.

We rarely give this much thought until things begin to go wrong. Often, when a structure is injured or undergoes progressive wear, balanced function is disrupted, and other co-dependent structures may deteriorate. Foot and ankle specialists are quite innovative, treating a broad range of patients at all stages of life, from newborns with foot deformity to active teens, adults, and seniors.

As the cases presented in this volume demonstrate, foot and ankle specialists are often confronted with complex conditions that include articular cartilage wear, bone fracture and deformity, ligamentous incompetence, and tendon rupture or insufficiency. HSS surgeons are prominently involved in research that leads to new techniques that improve treatment outcomes for these conditions.

In this issue, we highlight how HSS foot and ankle surgeons have expertly evaluated and corrected anatomical deficiencies in managing three very challenging conditions.

In Case 1, Scott J. Ellis, MD, Lauren E. Roberts, MD, and Aoife MacMahon, BA, describe reconstruction of complex flatfoot deformity with a dorsal bunion. In Case 2, Mark C. Drakos, MD, and James Davies, MD, explain the innovative soft tissue procedures required to repair a large Achilles tendon defect using quadruple-bundle hamstring autograft with flexor hallucis longus transfer. In Case 3, Constantine Demetracopoulos, MD, and Amelia Hummel, BA, describe a two-stage procedure to carry out a complex total ankle arthroplasty in a patient with flatfoot deformity and deltoid insufficiency.

• Reconstruction of Complex Flatfoot Deformity with a Dorsal Bunion
• Open Repair of a Large Achilles Tendon Defect Using Quadruple-Bundle Hamstring Autograft with Flexor Hallucis Longus Transfer
• Total Ankle Arthroplasty in Flatfoot Deformity with Deltoid Insufficiency

From the Director

Thomas P. Sculco, MD

The Stavros Niarchos Foundation Complex Joint Reconstruction Center (SNF CJRC) was created to provide specialized care to patients with the most difficult joint problems, primarily in failed joint replacements. The SNF CJRC has an active educational component, with a clinical and research fellowship, and research at the SNF CJRC has been awarded over $225,000 in grants this year. In addition, more than 1200 patients have been entered into a prospective registry that will provide outcomes data to improve techniques for the treatment of patients with these complex conditions. The SNF CJRC will host two international symposia in 2019, one on acetabular bone loss in revision total hip replacement and another on the difficult challenge of bacterial biofilms in the treatment of periprosthetic joint infection.

In this issue, 3 cases are presented involving revision total knee arthroplasty (TKA). Many of our patients have undergone revision TKA elsewhere, presenting to us with often debilitating complications such as chronic periprosthetic joint infection, soft-tissue defects, bone loss, and damaged implants. In Case 1, authors Shawn S. Richardson, MD, and Thomas P. Sculco, MD, discuss a severe adverse outcome of TKA, chronic extensor mechanism disruption with global knee instability, which required an extensor allograft and hinge prosthesis to improve patient function and restore knee extensor power. In Case 2, authors Jason L. Blevins, MD, Victoria Tam, and Michael B. Cross, MD, highlight the successful treatment of a patient with long-term periprosthetic joint infection who had severely compromised bone and soft tissue. In Case 3, authors Ivan De Martino, MD, Michael-Alexander Malahias, MD, PhD, and Peter K. Sculco, MD, describe the complex treatment course for a patient with massive metaphyseal bone deficits requiring prosthetic and bone augmentation.

All three cases illustrate the need for a multidisciplinary approach to management of complex cases—including collaboration among experts in infectious disease, specialized imaging, biomechanics, and surgical treatment. The SNF CJRC is committed to caring for patients with these most challenging conditions and strives through clinical and basic science research to provide the most innovative and evidence-based treatment to alleviate the major dysfunction caused by these failures.

• Chronic Extensor Mechanism Deficiency After Total Knee Arthroplasty: Treatment With Allograft Reconstruction
• Chronic Periprosthetic Joint Infection: Treatment With Repeat 2-Stage Static Spacer Followed by Distal Femoral Replacement
• Metaphyseal Bone Deficits in Revision Total Knee Arthroplasty: Treatment With Metaphyseal Cones