Fracture Risk in Ulnohumeral Arthroplasty-A Biomechanical Study.

PURPOSE: Ulnohumeral arthroplasty, also known as the Outerbridge-Kashiwagi procedure, was popularized after reports of successful results in 1978, and has long been a means of management for ulnohumeral arthritis. However, there are concerns over the loss of integrity of the distal humerus as a result of fenestration. The purpose of this study was to examine the relationship between the size of fenestration and fracture risk. METHODS: Using a validated fourth-generation sawbones model, load to failure and site of fracture were investigated following incrementally increasing distal humeral fenestration sizes. Each sample was subjected to a uniform extension stress on a materials testing system, with 5 samples run for each group. The experimental groups began with a fenestration size of 10 mm and increased by 3 mm increments up to 31 mm. Load at failure and site of fracture were recorded for each sample. RESULTS: Forty-five fourth-generation sawbones samples were tested. Average load at sample failure was equivalent for each fenestration group up to 25 mm. At 28 mm, average load to failure began to decrease, and was statistically significant beginning between 28 mm and 31 mm. At 28 mm, 4 of 5 samples fractured through the fenestration, and at 31 mm, all 5 samples fractured through the fenestration. This change in fracture site became statistically significant between 25 mm and 28 mm. CONCLUSIONS: Distal humeral fenestration does compromise its structural integrity; however, for resection in the range of 10-25 mm, there is no increased risk of fracture. CLINICAL RELEVANCE: On the basis of this biomechanical model, the authors do not recommend any activity limitations after initial surgical recovery, but do recommend against distal humeral fenestrations larger than 25 mm when performing this procedure.

Arthroscopic Management of Elbow Osteoarthritis.

The incidence of osteoarthritis in the general population is low, but it can be seen in manual laborers, throwing athletes, and people dependent on crutches and wheelchairs. Patients often complain of pain at the terminal extents of motion, and imaging shows osteophyte formation at the tips of the coronoid and olecranon processes as well as thickening of the bone between the coronoid and the olecranon fossae. Recent advances in arthroscopic instrumentation and techniques have led to a growing interest in the arthroscopic treatment of elbow osteoarthritis. This article provides a review of basic arthroscopic elbow anatomy and the most common procedures, including diagnostic arthroscopy, loose body removal, and arthroscopic osteocapsular and ulnohumeral arthroplasty. As techniques advance, there might be interest in further procedures including arthroscopic-assisted interpositional arthroplasty. Although complications such as persistent drainage and nerve injury are frequently mentioned with elbow arthroscopy, the actual incidence of such complications remains low.

Wide Decompression May Render the Ulnar Nerve Unstable: A Cadaveric Study.

The purpose of this study was to evaluate for ulnar nerve instability following incrementally widened in situ decompression. A standard release of the ulnar nerve was performed in 16 cadaveric elbows, extending from 7cm distal to the medial epicondyle, and then released proximally for a total of 10 cm in 2-cm increments. Eight of the 16 elbows (50%) displayed subluxation of the ulnar nerve following complete in situ decompression. The rate of subluxation was found to increase with increasing length of proximal decompression. The greatest increase in rate of subluxation was seen beyond 4 cm proximal to the medial epicondyle. Cubital tunnel release should be limited to decompression of only the cubital tunnel if clinical and electrodiagnostic studies indicate that the cubital tunnel is the source of compression.

Targeted Muscle Reinnervation of the Brachium: An Anatomic Study of Musculocutaneous and Radial Nerve Motor Points Relative to Proximal Landmarks.

PURPOSE: Targeted muscle reinnervation (TMR) offers enhanced prosthetic use by harnessing additional neural control from unused nerves in the amputated limb. The purpose of this study was to document the location and number of motor end plates to each muscle commonly used in TMR in the brachium relative to proximally based bony landmarks. METHODS: We dissected 18 matched upper limbs (9 fresh-frozen cadavers). The locations of each of the nerves' muscular insertions into the medial biceps and brachialis were measured relative to the anterolateral tip of the acromion. The terminal branches to the lateral triceps were measured relative to the posterolateral tip of the acromion. Both the number of branches and the location of the muscular insertions were documented. Common descriptive statistics were used to describe the data. RESULTS: There was a median of 2 branches to the medial biceps located 19.6 cm from the anterolateral tip of the acromion (range, 15-25 cm). There was a median of 3.5 branches to the brachialis located 24.2 cm from the anterolateral tip of the acromion (range, 19-27.5 cm). There was a median of 2.5 branches to the lateral triceps located 21.6 cm from the posterolateral tip of the acromion (range, 11-29 cm). The mean distances to the primary branch muscle and the number of smaller branches were not significantly different when compared by sex or side. CONCLUSIONS: Motor points for the medial biceps, brachialis, and lateral triceps can be identified reliably using proximal landmarks in targeted muscle reinnervation. CLINICAL RELEVANCE: The data obtained from this study may assist the surgeon in localizing the nerve branches and muscular insertions for the commonly used muscles for TMR of the brachium.

Longitudinal split tear of the extensor pollicis brevis tendon: report of 2 cases.

Two patients presented with radial-sided wrist pain and longitudinal split tears of the extensor pollicis brevis tendon. Surgical debridement and repair was performed on the first patient with good results. Early diagnosis in the second patient led to successful treatment with immobilization alone. If diagnostic maneuvers for de Quervain tenosynovitis produce pain in a location other than the radial styloid, advanced imaging should be considered to identify other anatomic causes for the pain.

Anthropometry of the Human Scaphoid Waist by Three-Dimensional Computed Tomography.

Published measurements for the scaphoid are scarce. The purpose of this study is to define anthropometric norms for the waist of the scaphoid to assist in optimizing bone graft quantity and implant use. Computed tomography images of the wrist were reviewed by three surgeons. Anthropometric data were gathered, including the scaphoid waist diameter in two dimensions and the scaphoid waist volume. Each study was measured twice, allowing for determination of inter- and intraobserver reliability. Forty-three studies were examined (23 female and 20 male). Average measurements of the scaphoid waist were 11.28 ± 0.26 mm in the sagittal plane and 8.70 ± 0.17 mm in the coronal plane, and the waist volume was 715 ± 33.0 mm3. Specific measures of the narrowest portion of the scaphoid are provided by this study. Measurements of the scaphoid waist through the use of three-dimensional imaging are an accurate method with good inter- and intraobserver reliability. The measurements obtained from this study can be applied to guide graft and implant selection for treatment of scaphoid waist fractures and nonunions.

The intermetacarpal angle screening test for ulnar-sided carpometacarpal fracture-dislocations.

PURPOSE: Ulnar-sided carpometacarpal injuries can be difficult to diagnose radiographically. We hypothesized that the resting position of the normal hand during lateral radiography provides a consistent relationship between the rays and that dorsal subluxation of the metacarpal base in fracture-dislocations increases the angle between the uninjured index and long metacarpals and the injured small metacarpal. METHODS: A control group of 100 consecutive patients with normal hand radiographs and a series of 12 patients with known carpometacarpal fracture-dislocations were examined. Angles between the index and small metacarpal shaft (I-S IMA) and between the long and small metacarpal shaft (L-S IMA) were measured on the lateral hand radiograph. RESULTS: In the control group, the mean I-S IMA and L-S IMA were both 6°. In the study group, the mean I-S IMA was 18°, and the mean L-S IMA was 16°. Intraobserver and interobserver reliability was good to excellent for both groups, and a statistical difference existed between the normal and study groups. Based on box-plot analysis of normal and abnormal IMAs, a natural dividing line existed at 10°. With this dividing line, the I-S IMA had a sensitivity of 92% and a specificity of 81%, and the L-S IMA had a sensitivity of 83% and a specificity of 84%. CONCLUSIONS: Both the I-S IMA and the L-S IMA were useful screening measurements on lateral hand radiographs for detection of ulnar-sided carpometacarpal fracture-dislocations. When evaluating posttraumatic ulnar-sided hand pain, advanced imaging should be considered if the I-S IMA or the L-S IMA is greater than 10°.

Hand infections.

Hand infections are commonly seen by orthopedic surgeons as well as emergency room and primary care physicians. Identifying the cause of the infection and initiating prompt and appropriate medical or surgical treatment can prevent substantial morbidity. The most common bacteria implicated in hand infections remain Staphylococcus aureus and Streptococcus species. Methicillin-resistant S aureus infections have become prevalent and represent a difficult problem best treated with empiric antibiotic therapy until the organism can be confirmed. Other organisms can be involved in specific situations that will be reviewed. Types of infections include cellulitis, superficial abscesses, deep abscesses, septic arthritis, and osteomyelitis. In recent years, treatment of these infections has become challenging owing to increased virulence of some organisms and drug resistance. Treatment involves a combination of proper antimicrobial therapy, immobilization, edema control, and adequate surgical therapy. Best practice management requires use of appropriate diagnostic tools, understanding by the surgeon of the unique and complex anatomy of the hand, and proper antibiotic selection in consultation with infectious disease specialists.

Orthopedic manifestations and management of patients with von Willebrand disease.

Von Willebrand Disease is the most common inherited bleeding disorder and can present challenges to orthopedic surgeons in managing perioperative bleeding and treating orthopedic problems that manifest as a result of the disease. Appropriate history taking is essential to identify these patients prior to surgery. The most effective management of von Willebrand disease will be achieved with close consultation between the surgeon, anesthesiologist, internist or pediatrician, hematologist, and patient. With appropriate planning, these patients can undergo major orthopedic procedures safely and effectively.

The AOA-JOA 2014 exchange traveling fellowship: Banzai and beyond.

The American Orthopaedic Association-Japanese Orthopaedic Association (AOA-JOA) traveling fellowship was established in 1992 as a method for creating collaboration between the American and Japanese orthopaedic communities and providing a friendly exchange of current practices and scientific endeavors. The fellowship is designed to allow early-career orthopaedic surgeons the opportunity to participate in international travel and scholarship. This year's traveling fellows (Hassan Mir, Wakenda Tyler, Leo Kroonen, and Dan Zlotolow) all hail from different parts of the United States and have a variety of practice subspecialties. During the fellowship, the fellows were able to visit five academic centers that spanned the entire country of Japan as well as the JOA meeting in Kobe. The experience is one that contributed to the growth and development of each fellow's practices and depth of understanding of orthopaedic surgery.

Cubital tunnel syndrome.

Compression of the ulnar nerve at the elbow, or cubital tunnel syndrome, is the second most common peripheral nerve compression syndrome in the upper extremity. Diagnosis is made through a good history and physical examination. Electrodiagnostic testing can confirm the diagnosis and severity of injury to the nerve. Surgical intervention is indicated when nonoperative treatment does not relieve the symptoms. There is currently no consensus on the best surgical treatment of cubital tunnel syndrome. However, the only randomized prospective studies to compare treatment options to date indicate that simple decompression and anterior transposition yield comparable results.

Prader-Willi Syndrome: clinical concerns for the orthopaedic surgeon.

BACKGROUND: Prader-Willi Syndrome (PWS) is a chromosome 15 disorder characterized by hypotonia, hypogonadism, hyperphagia, and obesity. Musculoskeletal manifestations, including scoliosis, hip dysplasia, and lower limb alignment abnormalities, are well described in the orthopaedic literature. However, care of this patient population from the orthopaedic surgeon's perspective is complicated by other clinical manifestations of PWS. Osteopenia, psychiatric disorders, and diminished pain sensitivity are frequently noted in PWS but are not discussed in the orthopaedic literature. The authors present a clinical review of an 8-year experience of caring for 31 patients with PWS to highlight all clinical concerns that influence orthopaedic management. METHODS: Thirty-one institutionalized patients diagnosed with PWS were examined and all past medical records were reviewed. Patient demographics, genetic testing, musculoskeletal diagnoses, psychiatric diagnoses, and clinical behaviors were recorded. Radiological studies performed in the course of routine clinical care were evaluated. RESULTS: Twenty-three men and 8 women, with an average age of 22 years (range, 8-39 years), were studied. A chromosome 15q abnormality was confirmed in 18 patients. Scoliosis was clinically detected in 21 of 30 patients and confirmed by radiographs in 14 of these 24 patients (overall with scoliosis, 45%) with an average primary curve of 27 degrees; 3 were braced, and 2 underwent spinal fusion. Radiographs also revealed diminished cervical lordosis and increased cervicothoracic kyphosis in 16 patients, a previously undescribed finding. Hip radiographs of 26 patients revealed dysplasia in 2 patients (13%); no slipped capital femoral epiphysis were identified. Fourteen patients had sustained a total of 58 fractures, with 6 patients sustaining multiple fractures (range, 2-7). Six patients have undergone orthopaedic surgical procedures with one major complication (spinal infection). Fracture management was associated with frequent minor complications. Bone densitometry was performed on 14 patients; 8 patients had osteopenia, and 4 had osteoporosis based on lumbar spine z scores. Twenty-six patients had Axis I psychiatric diagnoses including impulse control disorder (7), organic personality disorder (6), oppositional defiant disorder (5), dysthymic disorder (4), depressive disorder not otherwise specified (3), attention-deficit/hyperactivity disorder (2), and obsessive-compulsive disorder (2). Nine patients exhibited self-mutilating behaviors. CONCLUSIONS: Osteopenia, poor impulse control and defiant behaviors, and diminished pain sensitivity are aspects of PWS that may complicate all facets of orthopaedic nonsurgical and surgical management in this patient population. The treating orthopaedic surgeon must plan carefully and proceed with caution when treating children and adults with PWS.