A Review on Volar Fracture-Dislocations of the Proximal Interphalangeal Joint.

Volar fracture-dislocations of the proximal interphalangeal joint are rare injuries caused by an axial force on a flexed digit resulting in an avulsion fracture of the dorsal lip of the middle phalanx with volar dislocation of the joint. This volar subtype is analogous to the more common dorsal subtype with a mirror image fracture on the dorsal lip of the middle phalanx. The main significance in this type of injury lies in the disruption of the extensor mechanism at the central slip. The goals of treatment, apart from restoring a congruent and stable joint, is to restore the extensor mechanism to prevent a boutonnière deformity. In this article, we summarise the current literature and discuss the principles for treatment of this uncommon injury. Level of Evidence: Level V (Therapeutic).

Emergency Hand and Reconstructive Microsurgery in the COVID-19-Positive Patient.

The case spectrum in hand surgery is one of extremes-purely elective day surgery cases under local anesthesia to mangling limb injuries that require immediate, and frequently, lengthy, surgery. Despite the cancellation of most elective orthopedic and plastic surgical procedures, hand surgeons around the world continue to see a steady stream of limb-threatening cases such as severe trauma and infections that require emergent surgical care. With the increase in community-spread, an increasing number of COVID-19-infected patients may be asymptomatic or have mild, nonspecific or atypical symptoms. Some of them may already have an ongoing, severe infection. The time-sensitive nature of some of these cases means that hand surgeons may need to operate urgently on patients who may be suspected of COVID-19 infections, often before confirmatory test results are available. General guidelines for perioperative care of the COVID-19-positive patient have been published. However, our practices differ from those of general orthopedic and plastic surgery, primarily because of the focus on trauma. This article discusses the perioperative and technical considerations that are essential to manage the COVID-19 patient requiring emergency care, without compromising clinical outcomes and while ensuring the safety of the attending staff.

Ex-vivo Tendon Repair Augmented with Bone Marrow Derived Mesenchymal Stem Cells Stimulated with Myostatin for Tenogenesis.

BACKGROUND: To investigate the effect of myostatin (GDF-8) stimulation of bone marrow derived mesenchymal stem cells (BMSCs) on tenogenesis in the setting of tendon repair. GDF-8 has demonstrated the ability to augment tenogenesis and we sought to identify if this effect could lead to the focused differentiation of pluripotential stem cells down a tenocyte lineage ex vivo. METHODS: Cadaveric upper limb flexor tendons were harvested, decellularized and divided into 1 cm segments. Sutures seeded with stem cells were passed through tendon segments to simulate repair. The repaired tendons were then cultured either with or without myostatin for 3, 5, and 7 days. The experiment was also repeated with non-decellularized tendons for a total of 4 groups. The tendons were then evaluated for the expression of scleraxis and tenomodulin, two biomarkers for tendon. RESULTS: Myostatin stimulation led to an increase in expression of tenomodulin and scleraxis at 5 and 7 days in both the decellularized and non-decellularized tendons. Myostatin increased the differentiation of BMSCs into tenocytes and/or led to the upregulation of tenomodulin and scleraxis production by the native tenocytes present within the non-decellularized tendons. CONCLUSIONS: The addition of myostatin to BMSCs leads to tenocyte differentiation as evidenced by the expression of tenocyte biomarkers, scleraxis and tenomodulin. This effect is maintained in an ex vivo tendon repair model suggestive that these cells survive the passage through tendon tissue and remain metabolically active.

Mean 5-Year Follow-up for Suture Button Suspensionplasty in the Treatment of Thumb Carpometacarpal Joint Osteoarthritis.

PURPOSE: Suture button suspensionplasty (SBS) has been used to treat thumb carpometacarpal joint osteoarthritis (CMC joint OA). Although promising short-term outcomes have been reported, no outcomes beyond 4 years have been published. The aim of this article is to report intermediate outcomes of SBS. METHODS: We reviewed the charts of 14 patients who underwent 16 SBS procedures for symptomatic thumb CMC joint OA. We recorded demographic data, preoperative Eaton stage, length of follow-up, Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire scores, as well as pinch strength, grip strength, range of motion, and metacarpal subsidence. Operative time and postoperative complications were documented. RESULTS: Average age was 64 years. There were 12 women and 2 men. Preoperative Eaton stages were III and IV in 8 thumbs each. Mean operative time was 93 minutes. Mean follow-up was 64 months with mean Quick-Disabilities of the Arm, Shoulder, and Hand score improvement of 58.2. Mean palmar and radial abduction were 105% and 97%, respectively, of the nonsurgical thumb. Kapandji scores for all operated thumbs were either 9 or 10. Pinch and grip strength were 107% and 102%, respectively, of the nonsurgical side. Mean trapezial space height was 71%. One patient underwent removal of a symptomatic implant and 2 patients had transient neuropraxia of the dorsal radial sensory nerve. CONCLUSIONS: Favorable outcomes (improvement in range of motion and pain relief) of SBS remain durable over time. Our results show that improvement in strength may also be expected over time when using SBS after trapeziectomy for the treatment of thumb CMC joint OA. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Incidence of Posterior Interosseous Nerve Trauma During Creation of the 3-4 Wrist Arthroscopy Portal in Cadavers.

PURPOSE: To describe histologic evidence of nerve trauma during the creation and use of the 3-4 portal. METHODS: Fourteen fresh-frozen cadaveric wrists were mounted on a custom-built frame that simulated a wrist arthroscopy traction tower. After the 3-4 portal was created in the usual manner, the skin was dissected off to identify possible trauma to the posterior interosseous nerve (PIN). Specimens were categorized into those where there was clearly no trauma to the PIN and those where trauma was possible. In the cases where trauma was possible, we harvested the PIN with a cuff of the proximal edge of the portal and examined the cross-sectional histology of the most distal sections for the presence of neural tissue. RESULTS: There was clearly no trauma to the PIN in 3 of the wrists during the creation of the 3-4 portal. In the remaining 11 wrists with possible trauma to the PIN, we identified axonal tissue on histologic examination at the proximal edge of the 3-4 portal in 7 of these specimens. In summary, 50% (7 of 14) of our specimens had visual and histologic evidence of trauma to the PIN. CONCLUSIONS: Based on the findings of this study, there may be more instances of trauma to the PIN during routine wrist arthroscopy than have been previously reported. CLINICAL RELEVANCE: Findings suggest that transection or injury to this nerve may not lead to any clinical sequelae. However, if there is an instance where a patient has persistent, otherwise unexplained, dorsal wrist pain after a wrist arthroscopy procedure, iatrogenic neuroma of the PIN may be responsible and should be considered.

Biomechanics of Internal Fixation Modalities for Middle Phalangeal Base Fracture Dislocation.

BACKGROUND: Internal fixation modalities of unstable (>50 percent articular involvement) middle phalangeal volar lip fracture-dislocations include interfragmentary screw and volar buttress plating. This study investigates the mechanical properties (yield strength, ultimate tensile strength, and stiffness) of interfragmentary screw (IS), simple buttress plating (BP) and buttress plating with subchondral screw (BP+S). METHODS: Fifteen cadaveric digits (5 index, 5 middle, and 5 ring) were prepared by excising its skin envelope and flexor tendons while preserving the structures around the proximal interphalangeal joint. An oblique osteotomy involving 50 percent of the articular surface was performed, and this was fixed with based on its study group: interfragmentary screw (IS), simple buttress plating (BP) and buttress plating with subchondral screw (BP+S). These specimens were then loaded to failure. RESULTS: Yield strength was as follows: BP+S (33.5±9.76 N), IS (13.6±5.46 N), and BP (8.1±3.84 N). Ultimate tensile strength was as follows: BP+S (49.1±21.4 N), IS (15.6±5.19 N), and BP (8.86±3.99 N). Stiffness was as follows: BP+S (4.77±1.32 N/mm), IS (2.44±0.86 N/mm), and BP (1.84±0.71 N/mm). CONCLUSIONS: A buttress plate and screw construct confers significantly more stability than either interfragmentary screw or buttress plate only fixation in an experimental model.

Post-Reduction Stability of the Proximal Interphalangeal Joint after Dorsal Fracture Dislocation-A Cadaveric Study.

BACKGROUND: Proximal interphalangeal joint (PIPJ) dorsal fracture dislocations (DFD) are challenging injuries. Treatment aims to achieve stability of the PIPJ after reduction so that early motion can be initiated. We studied how increasing articular destruction would affect post reduction stability and investigate the amount of traction and PIPJ flexion needed to maintain the reduction. METHODS: Increasing amounts (20%, 40% and 60%) of damage to the volar lip of the middle phalanx in cadaveric specimens were created to represent PIPJ DFD that were stable, of tenuous stability and frankly unstable. Traction forces and PIPJ flexion needed to maintain the reduction were then measured. RESULTS: The PIPJ DFD with 20% damage were stable and did not subluxe while the one with 40% articular involvement was stable after reduction. For unstable the PIPJ with 60% involvement, the more the PIPJ was flexed, the less traction force was needed to hold the joint in reduction. For PIPJ flexion of 20 degrees, a minimum 4.4N of force is needed to maintain reduction while PIPJ flexion of 10 degrees required a minimum 5.0N of force. No amount of force could maintain PIPJ reduction if traction was performed in full extension. CONCLUSIONS: In our model, PIPJ DFD with less than 30% articular damage are stable while those with 30% to 50% of involvement have tenuous stability. For the unstable PIPJ DFD, traction obviates the need for excessive flexion of the PIPJ to maintain joint reduction. This information should be considered in treatment modalities for PIPJ DFD, as well in the design of external traction devices for the treatment of PIPJ DFD.

Radial Nerve Tendon Transfers.

Radial nerve palsy typically occurs as a result of trauma or iatrogenic injury and leads to the loss of wrist extension, finger extension, thumb extension, and a reduction in grip strength. In the absence of nerve recovery, reconstruction of motor function involves tendon transfer surgery. The most common donor tendons include the pronator teres, wrist flexors, and finger flexors. The type of tendon transfer is classified based on the donor for the extensor digitorum communis. Good outcomes have been reported for most methods of radial nerve tendon transfers as is typical for positional tendon transfers not requiring significant power.

Hand Fractures: Indications, the Tried and True and New Innovations.

Hand fractures are the second most common fracture of the upper extremity, and management of patients with these injuries is common for most hand surgery practices. In this article, we outline the principles of management of these injuries with a special focus on those that are common or complex. We also highlight recent innovations in the context of these injuries. From this cross-section of contemporary evidence on phalangeal and metacarpal fracture treatment, we have noted a trend toward minimally invasive surgery with immediate postoperative mobilization, the use of wide-awake anesthesia, as well as sustained investigation and innovation in the biomechanics and treatment of proximal interphalangeal joint fracture dislocations.

Surgical Approaches to the Proximal Interphalangeal Joint.

The proximal interphalangeal (PIP) joint may be affected by many conditions such as arthropathy, fractures, dislocations, and malunions. Whereas some of these conditions may be treated nonsurgically, many require open surgical intervention. Open interventions include implant arthroplasty or arthrodesis for arthropathy, open reduction internal fixation, or hemi-hamate arthroplasty for dorsal fracture-dislocations. Volar plate arthroplasty and corrective osteotomy for malunion about the PIP joint are also surgeries that may be required. The traditional approach to the PIP joint has been dorsal, which damages the delicate extensor apparatus with subsequent development of an extensor lag. This has led surgeons to explore volar and lateral approaches to the PIP joint. In this article, we describe each of these surgical approaches, discuss their advantages and disadvantages, and provide some guidance on which approach to choose based on the surgery that is to be performed.