Infections of the Upper Extremity: New Developments and Challenges

Hand infections are common in all patient populations. However, because of variability in presentation and severity, they can be challenging to correctly diagnose and complex to manage. It is important to be aware of special populations such as children, individuals who are immunocompromised, those with diabetes, and intravenous drug users who may have uncommon pathogens or unusual types of infection. Atypical or rare bacterial and fungal infections, even in an immunocompetent host, can be equally challenging to manage. In each of these scenarios, it is critical to be familiar with associated conditions to avoid mismanagement and initiate an appropriate team-based approach for care involving surgery and consultation with an infectious disease specialist.

Radial head replacement with a bipolar system: an average 10-year follow-up

BACKGROUND

We report the long-term results of a cohort of patients after radial head replacement with a bipolar design and a smooth cementless stem at a mean follow-up of 10.4 years.

METHODS

Of 17 possible patients from a previous minimum 2-year follow-up study, 16 were available for review. Patients were assessed using clinical and radiographic examination and with standardized outcome measures. Range of motion, stability, and radiographic evaluation of implant loosening and joint degeneration were assessed. Comparisons were performed using the Wilcoxon signed rank test for unequal groups.

RESULTS

The average follow-up was 10.5 years (range, 8.5-12 years). The median visual analog scale was 1 (range, 0-5), Minnesota Elbow Performance Index was 93 (range, 70-100), and the Disabilities of the Arm, Shoulder and Hand was 7.5 (range, 0-53). Range of motion was decreased on the operative side compared with the nonoperative side for flexion/extension (P = .005) and pronation/supination (P = .015). Grip strength was decreased on the affected side (P = .045). No patients had elbow instability. Significant arthritic changes developed in 2 patients at the ulnohumeral joint. The median cantilever quotient was 0.4 (range, 0.30-0.50). Osteolysis in zones 1 to 7 was found in all but 2 patients. The median stem radiolucency was 0.5 mm (range, 0.2-0.9 mm). No reoperations occurred since our previous report. Implant survival in this cohort was 97%.

CONCLUSION

Bipolar radial head prosthesis with a smooth cementless stem effectively restores elbow stability and function after comminuted radial head fractures with or without concomitant elbow instability. Our study demonstrates excellent long-term implant survival.

The morphology of proximal pole scaphoid fractures: implications for optimal screw placement

The purpose of this study was to measure the radiographic parameters of proximal pole scaphoid fractures, and calculate the ideal starting points and trajectories for antegrade screw insertion. Computed tomography scans of 19 consecutive patients with proximal pole fractures were studied using open source digital imaging and communications in medicine (DICOM) imaging measurement software. For scaphoid sagittal measurements, fracture inclination was measured with respect to the scaphoid axis. The ideal starting point for a screw in the proximal pole fragment was then identified on the scaphoid sagittal image that demonstrated the largest dimensions of the proximal pole, and hence the greatest screw thread purchase. Measurements were then taken for a standard screw trajectory in the axis of the scaphoid, and a trajectory that was perpendicular to the fracture line. The fracture inclination in the scaphoid sagittal plane was 25 (SD10) °, lying from proximal palmar to dorsal distal. The fracture inclination in the coronal plane was 9 (SD16) °, angling distal radial to proximal ulnar with reference to the coronal axis of the scaphoid. Using an ideal starting point that maximized the thread purchase in the proximal pole, we measured a maximum screw length of 20 (SD 2) mm when using a screw trajectory that was perpendicular to the fracture line. This was quite different from the same measurements taken in a trajectory in the axis of the scaphoid. We also identified a mean distance of approximately 10 mm from the dorsal fracture line to the ideal starting point. A precise understanding of this anatomy is critical when treating proximal pole scaphoid fractures surgically.

Fixation of proximal pole scaphoid nonunion with non-vascularized cancellous autograft

We present 20 patients with established proximal pole scaphoid nonunions treated with curettage and cancellous autograft from the distal radius and screw fixation. Fractures with significant proximal pole fragmentation were excluded. Patients were treated at a mean of 26 weeks after injury (range 12-72). Union occurred in 18 of 20 patients (90%) based on computed tomographic imaging. The two nonunions that did not heal were treated with repeat curettage and debridement and iliac crest bone grafting without revision of fixation. Union was achieved in both at a mean of 11 weeks after the revision procedures. Our findings suggest that non-vascularized cancellous autograft and antegrade fixation is a useful option for the treatment of proximal pole scaphoid nonunions.

LEVEL OF EVIDENCE

IV.

Re-cyclin' Cell-Cycle Components to Make NETs

Neutrophil extracellular traps (NETs) are critical for the clearance of large pathogens and are also implicated in thrombosis, autoimmunity, and cancer. In this issue of Developmental Cell, Amulic et al. (2017) show that the terminally differentiated, non-cycling neutrophils repurpose cell-cycle proteins and pathways to form NETs.

Cancer cells induce metastasis-supporting neutrophil extracellular DNA traps

Neutrophils, the most abundant type of leukocytes in blood, can form neutrophil extracellular traps (NETs). These are pathogen-trapping structures generated by expulsion of the neutrophil's DNA with associated proteolytic enzymes. NETs produced by infection can promote cancer metastasis. We show that metastatic breast cancer cells can induce neutrophils to form metastasis-supporting NETs in the absence of infection. Using intravital imaging, we observed NET-like structures around metastatic 4T1 cancer cells that had reached the lungs of mice. We also found NETs in clinical samples of triple-negative human breast cancer. The formation of NETs stimulated the invasion and migration of breast cancer cells in vitro. Inhibiting NET formation or digesting NETs with deoxyribonuclease I (DNase I) blocked these processes. Treatment with NET-digesting, DNase I-coated nanoparticles markedly reduced lung metastases in mice. Our data suggest that induction of NETs by cancer cells is a previously unidentified metastasis-promoting tumor-host interaction and a potential therapeutic target.

Medial Gastrocnemius Flap in the Course of Treatment for an Infection at the Site of a Total Knee Arthroplasty

Introduction

The pedicled medial gastrocnemius flap provides a robust coverage option for most soft-tissue deficiencies over the distal anterior aspect of the knee encountered in the setting of an infection after total knee arthroplasty.

Indications & Contraindications

Step 1 Patient Positioning

Position the patient supine with an ipsilateral sterile thigh tourniquet to allow room for harvest of a split-thickness skin graft as needed.

Step 2 Revision Arthroplasty for Infection

Perform the arthroplasty to address the underlying deep infection (e.g., irrigation and debridement with exchange of modular components, component removal with antibiotic spacer placement, antibiotic spacer exchange, or second-stage reimplantation) prior to the medial gastrocnemius flap that is utilized for soft-tissue coverage.

Step 3 Incision and Approach for the Medial Gastrocnemius Flap

Use one of two different surgical approaches for the exposure and elevation of the medial gastrocnemius muscle and the identification of its vascular pedicle: the medial approach or the posterior midline approach.

Step 4 Elevation of the Medial Gastrocnemius Flap

Protect the sural artery pedicle in the popliteal fossa because it is key to raising a viable medial gastrocnemius flap.

Step 5 Transposition and Insetting of the Flap Over the Defect

Rotate the flap and transpose it anteriorly over the defect either through a subcutaneous tunnel or by dividing the intervening skin bridge.

Step 6 Closure Skin-Grafting and Dressing Application

Complete the layered skin closure and place a split-thickness skin graft over the remaining exposed muscle flap and a nonadherent compressive bolster dressing or negative-pressure device over the skin graft to prevent hematoma under the skin graft.

Step 7 Postoperative Care

Progress range of motion of the knee once the flap and graft show evidence of survival, while an appropriate antibiotic regimen is completed.

Results

We recently reported the largest English-language series, to our knowledge, of medial gastrocnemius flaps performed for soft-tissue coverage in the course of treatment for infection after total knee arthroplasty¹³.

Pitfalls & Challenges

Synovial Chondromatosis of the Elbow With Asymptomatic Ulnar Nerve Compression

Primary synovial chondromatosis is a rare, benign, proliferative disease of hyaline cartilaginous bodies within the synovium of joints. We report a rare case of primary synovial chondromatosis diffusely affecting the ulnohumeral joint causing pain and motion limitations with extrusion into the cubital tunnel and compressing the ulnar nerve but without any preoperative signs or symptoms of ulnar nerve compression. The patient was successfully treated with an open synovectomy to limit disease progression and improve motion. This case highlights that synovial conditions of the elbow may involve the ulnar nerve even when a patient is asymptomatic. Preoperative use of magnetic resonance imaging of the elbow should be considered in patients undergoing either an open or arthroscopic synovectomy.

Controversies in Surgical Management of Recalcitrant Enthesopathy of the Extensor Carpi Radialis Brevis

Enthesopathy of the extensor carpi radialis brevis, often referred to as "tennis elbow," is common and responds to nonsurgical treatment in 80% to 90% of patients within 1 year. For those who proceed with surgery, much remains unclear regarding the ideal treatment. This paper discusses controversies in surgical management of extensor carpi radialis brevis enthesopathy including clinical outcomes of open versus arthroscopic techniques, the relevance of concomitant pathology addressed arthroscopically, and avenues for assessing comparative cost data.

Recent Scientific Advances Towards the Development of Tendon Healing Strategies

There exists a range of surgical and non-surgical approaches to the treatment of both acute and chronic tendon injuries. Despite surgical advances in the management of acute tears and increasing treatment options for tendinopathies, strategies frequently are unsuccessful, due to impaired mechanical properties of the treated tendon and/or a deficiency in progenitor cell activities. Hence, there is an urgent need for effective therapeutic strategies to augment intrinsic and/or surgical repair. Such approaches can benefit both tendinopathies and tendon tears which, due to their severity, appear to be irreversible or irreparable. Biologic therapies include the utilization of scaffolds as well as gene, growth factor, and cell delivery. These treatment modalities aim to provide mechanical durability or augment the biologic healing potential of the repaired tissue. Here, we review the emerging concepts and scientific evidence which provide a rationale for tissue engineering and regeneration strategies as well as discuss the clinical translation of recent innovations.

Arthroscopic-Assisted Outside-In Repair of Triangular Fibrocartilage Complex Tears

With advances in surgical instrumentation and techniques, as well as expanding surgical indications, wrist arthroscopy is now being used to treat a variety of conditions previously managed only with open techniques. Triangular fibrocartilage complex (TFCC) injuries remain among the most common causes of ulnar-sided wrist pain and can result from both acute and chronic mechanisms of injury. The most common mechanism of acute injury to the TFCC is a fall onto an outstretched hand with the wrist in a supinated, extended position. In patients with unrelenting pain, swelling, or mechanical symptoms despite a concerted effort at nonoperative management, which often consists of bracing, therapy, or injections, surgical intervention is often indicated. Treatment historically consisted of open exploration and repair; however, recently, arthroscopic-assisted and all-arthroscopic techniques have been described. We describe a safe, reproducible, and reliable surgical technique for arthroscopic-assisted outside-in repair of peripheral TFCC tears. In addition, a specific focus on surgical anatomy, including pearls and pitfalls for protecting the dorsal sensory branch of the ulnar nerve, is presented.

Clinical outcomes of proximal row carpectomy versus four-corner arthrodesis for post-traumatic wrist arthropathy: a systematic review

We conducted a systematic review of studies reporting clinical outcomes after proximal row carpectomy or to four-corner arthrodesis for scaphoid non-union advanced collapse or scapholunate advanced collapse arthritis. Seven studies (Levels I-III; 240 patients, 242 wrists) were evaluated. Significantly different post-operative values were as follows for four-corner arthrodesis versus proximal row carpectomy groups: wrist extension, 39 (SD 11º) versus 43 (SD 11º); wrist flexion, 32 (SD 10º) versus 36 (SD 11º); flexion-extension arc, 62 (SD 14º) versus 75 (SD 10º); radial deviation, 14 (SD 5º) versus 10 (SD 5º); hand grip strength as a percentage of contralateral side, 74% (SD 13) versus 67% (SD 16); overall complication rate, 29% versus 14%. The most common post-operative complications were non-union (grouped incidence, 7%) after four-corner arthrodesis and synovitis and clinically significant oedema (3.1%) after proximal row carpectomy. Radial deviation and post-operative hand grip strength (as a percentage of the contralateral side) were significantly better after four-corner arthrodesis. Four-corner arthrodesis gave significantly greater post-operative radial deviation and grip strength as a percentage of the opposite side. Wrist flexion, extension, and the flexion-extension arc were better after proximal row carpectomy, which also had a lower overall complication rate.

Is intralesional treatment of giant cell tumor of the distal radius comparable to resection with respect to local control and functional outcome?

BACKGROUND

A giant cell tumor is a benign locally aggressive tumor commonly seen in the distal radius with reported recurrence rates higher than tumors at other sites. The dilemma for the treating surgeon is deciding whether intralesional treatment is adequate compared with resection of the primary tumor for oncologic and functional outcomes. More information would be helpful to guide shared decision-making.

QUESTIONS/PURPOSES

We asked: (1) How will validated functional scores, ROM, and strength differ between resection versus intralesional excision for a giant cell tumor of the distal radius? (2) How will recurrence rate and reoperation differ between these types of treatments? (3) What are the complications resulting in reoperation after intralesional excision and resection procedures? (4) Is there a difference in functional outcome in treating a primary versus recurrent giant cell tumor with a resection arthrodesis?

METHODS

Between 1985 and 2008, 39 patients (39 wrists) were treated for primary giant cell tumor of the distal radius at two academic centers. Twenty patients underwent primary intralesional excision, typically in cases where bony architecture and cortical thickness were preserved, 15 underwent resection with radiocarpal arthrodesis, and four had resection with osteoarticular allograft. Resection regardless of reconstruction type was favored in cases with marked cortical expansion. A specific evaluation for purposes of the study with radiographs, ROM, grip strength, and pain and functional scores was performed at a minimum of 1 year for 21 patients (54%) and an additional 11 patients (28%) were available only by phone. We also assessed reoperations for recurrence and other complications via chart review.

RESULTS

With the numbers available, there were no differences in pain or functional scores or grip strength between groups; however, there was greater supination in the intralesional excision group (p=0.037). Tumors recurred in six of 17 wrists after intralesional excision and none of the 15 after en bloc resection (p=0.030). There was no relationship between tumor grade and recurrence. There were 12 reoperations in eight of 17 patients in the intralesional excision group but only one of 11 patients (p=0.049) who underwent resection arthrodesis with distal radius allograft had a reoperation. There were no differences in functional scores whether resection arthrodesis was performed as the primary procedure or to treat recurrence after intralesional excision.

CONCLUSIONS

Resection for giant cell tumor of the distal radius with distal radius allograft arthrodesis showed a lower recurrence rate, lower reoperation rate, and no apparent differences in functional outcome compared with joint salvage with intralesional excision. Because an arthrodesis for recurrence after intralesional procedures seems to function well, we believe that intralesional excision is reasonable to consider for initial treatment, but the patient should be informed about the relative benefits and risks of both options during the shared decision-making process. Because arthrodesis after recurrence functions similar to the initial resection and arthrodesis, an initial treatment with curettage remains a viable, and likely the standard, mode of treatment for most giant cell tumors of the distal radius unless there is extensive bone loss.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Local and regional flaps for hand coverage

Hand surgeons are frequently challenged by the unique requirements of soft tissue coverage of the hand. Whereas many smaller soft tissue defects without involvement of deep structures are amenable to healing by secondary intention or skin grafting, larger lesions and those with exposed tendon, bone, or joint often require vascularized coverage that allows rapid healing without wound contraction. The purpose of this review was to present an overview of local and regional flaps commonly used for soft tissue reconstruction within the hand.

Clinical and radiographic comparisons of two different radial head implant designs

BACKGROUND

There is little comparative data to guide implant choice for radial head replacements. The purpose of this study was to evaluate the clinical and radiographic results between patients who received a smooth-stemmed bipolar radial head implant and patients who received an in-growth monopolar prosthesis.

METHODS

Twenty-seven patients requiring a metallic radial head implant in the management of acute or chronic elbow trauma were evaluated. Fourteen patients received a smooth-stemmed bipolar prosthesis and 13 patients received a press-fit monopolar prosthesis. Patients returned for follow-up at an average of 33 months (range, 18-57). Outcome assessments included joint motion, elbow stability, grip strength, pain, the Mayo Elbow Performance Index, and the Disability of Arm, Shoulder and Hand questionnaire. Radiographs were reviewed for joint congruence, ectopic bone, periprosthetic osteolysis, degenerative arthritis, and capitellar wear, and selected patients were tested for inflammatory markers and metal ion levels.

RESULTS

The differences between patient groups for elbow flexion and forearm pronation averaged 10° or less. There were no other pertinent differences between groups for standardized patient and examiner-determined outcomes. There was a trend for ectopic bone to develop more commonly around the smooth-stemmed implants, while periprosthetic osteolysis was more pronounced in cases with the press-fit design. Inflammatory markers were normal, and metal ion levels did not exceed values reported for a well-functioning hip arthroplasty.

CONCLUSION

Outcomes at short- to mid-term follow-up were similar with either implant design. Loosening of a press-fit prosthesis may lead to extensive osteolysis, but of undetermined clinical consequence.

Radioscapholunate arthrodesis with compression screws and local autograft

Radioscapholunate arthrodesis is performed for patients who experience pain and disability from radiocarpal arthritis. Initial reports from the 1980s demonstrated high nonunion rates and marginal clinical outcomes. Improvements in surgical technique and clearly defined indications have reduced nonunion rates and improved patient satisfaction. We present a technique using headless compression screws inserted through a dorsal approach, which optimizes hardware placement and incorporates local bone graft harvested from the insertion site to supplement the arthrodesis.

Controlled treadmill exercise eliminates chondroid deposits and restores tensile properties in a new murine tendinopathy model

Tendinopathy is a widespread and disabling condition characterized by collagen fiber disruption and accumulation of a glycosaminoglycan-rich chondroid matrix. Recent clinical reports have illustrated the potential of mechanical loading (exercise) therapies to successfully treat chronic tendinopathies. We have developed a new murine tendinopathy model which requires a single injection of TGF-β1 into the Achilles tendon midsubstance followed by normal cage activity for 2 weeks. At this time, tendon maximum stress showed a dramatic (66%) reduction relative to that of normal controls and this persisted at four weeks. Loss of material properties was accompanied by abundant chondroid cells within the tendon (closely resembling the changes observed in human samples obtained intra-operatively) and increased expression of Acan, Col1a1, Col2a1, Col3a1, Fn1 and Mmp3. Mice subjected to two weeks of daily treadmill exercise following TGF-β1 injection showed a similar reduction in tendon material properties as the caged group. However, in mice subjected to 4 weeks of treadmill exercise, tendon maximum stress values were similar to those of naive controls. Tendons from the mice exercised for 4 weeks showed essentially no chondroid cells and the expression of Acan, Col1a1, Col2a1, Col3a1, and Mmp3 was significantly reduced relative to the 4-week cage group. This technically simple murine tendinopathy model is highly amenable to detailed mechanistic and translational studies of the biomechanical and cell biological pathways, that could be targeted to enhance healing of tendinopathy.

Arthroscopic treatment of peripheral triangular fibrocartilage complex tears with the deep fibers intact

PURPOSE

We describe a variant of triangular fibrocartilage complex (TFCC) tears in which the superficial fibers attaching to the ulnar capsule are torn, with preservation of deep fibers inserting on the fovea. We present the clinical and magnetic resonance imaging findings and the results of arthroscopic repair in patients with this injury.

METHODS

Twenty-nine wrists were treated arthroscopically for peripheral TFCC tears with outside-in suture repair of the TFCC to the ulnar capsule. A retrospective review of all cases was performed to assess the physical examination, magnetic resonance imaging, and intraoperative findings. Patients were evaluated at greater than 1 year with range of motion, grip strength, standard outcome measures, and a survey assessing return to work and sports.

RESULTS

Before surgery, all patients had complaints of ulnar-sided wrist pain with a stable distal radioulnar joint on examination. Twenty-six wrists (90%) were available for follow-up at a mean of 31 months. There was one repeat surgery, a re-tear that required revision TFCC repair. The preoperative visual analog scale and Disabilities of the Arm, Shoulder, and Hand scores improved from 5 and 38 to 1 and 9, respectively, at final follow-up. Side-to-side comparisons demonstrated no measurable loss in motion or grip strength. There were no cases of distal radioulnar joint instability at final follow-up. Of 11 high-level athletes in the total cohort, 7 (64%) were able to return to sports, including all of those in racquet sports; however, athletes who bore weight through their hands were unable to return to their sporting activity.

CONCLUSIONS

Tears of the TFCC superficial fibers with the deep fibers intact present with ulnar-sided wrist pain but without distal radioulnar joint instability. The results of outside-in repair of the articular disk back to the ulnar capsule demonstrated improvement in pain and function with no measurable objective losses. Return to sport was variable and appeared worse for those who bear weight through the hands.

Radiation therapy for heterotopic ossification prophylaxis afer high-risk elbow surgery

Heterotopic ossification (HO) is a common complication of elbow trauma or surgery. HO can impair joint function; when it does, surgical removal is required. Radiotherapy (RT) prevents HO formation in the hip. However, few data exist on the efficacy of RT in preventing HO formation in the elbow. We retrospectively analyzed the outcomes of elbow surgery followed by prophylactic single-fraction RT and use of nonsteroidal anti-inflammatory drugs (NSAIDs). All patients had ectopic bone resected at surgery or significant risk factors for development of ectopic bone. Of the 52 patients who underwent RT after high-risk elbow surgery, 44 had postoperative radiographs of the treated elbow available for evaluation. At a median follow-up of 136 days, 21 patients (48%) had radiographic evidence of HO. In all cases, however, the HO was small and not functionally significant. No complications were attributed to RT use. This retrospective review represents the largest published series of patients who have undergone postoperative RT to prevent HO formation in the elbow. Our findings support the idea that RT, in combination with NSAID use, is safe and efficacious in preventing development of clinically significant HO in the elbow.