A three-dimensional analysis of the sigmoid notch

Fractures of the distal radius are among the most common injuries of the upper extremity, though treatment has traditionally focused on restoration of the radiocarpal joint and late sequelae may persist. X-ray imaging underestimates sigmoid notch involvement following distal radius fractures. No classification system exists for disruption patterns of the sigmoid notch of the radius associated with distal radius fractures. This study quantifies the anatomy of the sigmoid notch and identifies the landmarks of the articular surface and proximal boundaries of the distal radioulnar joint (DRUJ) capsule. Computed tomography scans of freshly frozen cadaveric hands were used - followed by dissection, and three-dimensional reconstruction of the distal radius and sigmoid notch. The sigmoid notch surface was divided into two surfaces and measured. The Anterior Posterior (AP) and Proximal Distal (PD) widths of the articulating surface were reviewed, along with the radius of curvature, version angle and depth. The study showed that the sigmoid notch is flatter than previously believed - and only the distal 69% of its surface is covered by cartilage. On average, it has about nine degrees of retroversion, and its average inclination is almost parallel to the anatomical axis of the radius. Clinical implications exist for evaluation of the DRUJ involvement in distal radius fractures or degenerative diseases and for future development and evaluation of hemiarthroplasty replacement of the distal radius.

Treatment of unstable distal radius fractures with the volar locking plate

BACKGROUND

Open reduction and internal fixation using an interlocking plate system has gained popularity for the treatment of dorsally displaced distal radius fractures.

PURPOSE

To evaluate the functional and radiological results of treating unstable distal radius fractures with the volar locking plate.

PATIENTS AND METHODS

A retrospective review was conducted of patients from one institution using the volar locking plate to treat intra-articular and extra-articular distal radius fractures. Unstable distal radius fractures in 15 patients, comprising 3 men and 12 women with a mean age of 64.4 years (34-76 years), were treated with a volar locking compression plate (Acu-Loc distal radius plate system; Acumed, Oregon, USA) and followed up for a minimum of 1 year. Fractures were classified using the AO classification. Radiographic parameters of preoperative, postoperative, and final follow-up radiographs were compared. The time to initiation of active range of motion was determined. Final follow-up range of motion and complications were reported.

RESULTS

At final functional assessment, the scores of 5 patients were excellent, 7 patients good, and 3 patients fair according to Cooney's Clinical Scoring Chart. No non-union or infection occurred. Rupture of the flexor pollicis longus tendon occurred in 1 patient.

CONCLUSION

Treatment of unstable distal radius fractures with a volar locking plate leads to satisfactory results, provided the operative technique is carefully performed to prevent complications.

Outcome following acute primary distal ulna resection for comminuted distal ulna fractures at the time of operative fixation of unstable fractures of the distal radius

Optimal acute management of the highly comminuted distal ulna head/neck fracture sustained in conjunction with an unstable distal radius fracture requiring operative fixation is not well established. The purpose of the present study was to determine the clinical, radiographic, and functional outcomes following acute primary distal ulna resection for comminuted distal ulna fractures performed in conjunction with the operative fixation of unstable distal radius fractures. Between 2000 and 2007, 11 consecutive patients, mean age 62 years (range, 30-75) were treated for concomitant closed, comminuted, unstable fractures of the distal radius and ulna metaphysis. All 11 patients underwent distal ulna resection through a separate dorsal ulnar incision with ECU tenodesis following surgical fixation of the distal radius fracture. According to the Q modifier of the Comprehensive Classification of Fractures, there were six comminuted fractures of the ulnar neck (Q3) and five fractures of the head/neck (Q5). Operative fixation of the distal radius fracture included volar plate fixation in four patients and spanning external fixation with supplemental percutaneous Kirschner wires in seven patients. At a mean of 42 months (range, 18-61 months) postoperatively, clinical, radiographic, and wrist-specific functional outcome with the modified Gartland and Werley wrist score were evaluated. At latest follow-up, mean wrist range of motion measured 53 degrees flexion (range, 35-60 degrees), 52 degrees extension (range, 30-60 degrees), 81 degrees pronation (range, 75-85 degrees), and 77 degrees supination (range, 70-85 degrees). Mean grip strength measured 90% of the contralateral, uninjured extremity (range, 50-133%). No patient had distal ulna instability. Final radiographic assessment demonstrated restoration of distal radius articular alignment. According to the system of Gartland and Werley as modified by Sarmiento, there were seven excellent and four good results. No patient has required a secondary surgical procedure. Acute primary distal ulna resection yields satisfactory clinical, radiographic, and functional results in appropriately selected patients and represents a reliable alternative to open reduction and internal fixation when anatomic restoration of the distal ulna/sigmoid notch cannot be achieved. Primary distal ulna resection with distal radius fracture fixation may help avoid secondary procedures related to distal ulna fixation or symptomatic post-traumatic distal radioulnar joint arthrosis.

The effect of ulnar styloid fractures on patient-rated outcomes after volar locking plating of distal radius fractures

PURPOSE

Ulnar styloid fractures commonly occur with distal radius fractures (DRFs). Ulnar styloid fractures that involve the insertion of the radioulnar ligaments can cause distal radioulnar joint (DRUJ) instability, and the literature suggests that these fractures should be treated with open reduction internal fixation (ORIF). However, in the absence of DRUJ instability, the effects of ulnar styloid fractures are unknown. The purpose of this study is to evaluate the outcome of ulnar styloid fractures without DRUJ instability on patient-rated outcomes after DRF ORIF.

METHODS

Between 2003 and 2008, a cohort of DRF patients treated with volar plating was enrolled. Patients with DRUJ instability treated at the time of distal radius ORIF were excluded. Radiographs were evaluated to identify and characterize ulnar styloid fractures. Patient-rated outcomes were measured at 6 weeks, 3 months, 6 months, and 12 months postoperatively using the Michigan Hand Outcomes Questionnaire (MHQ). Regression analysis was performed to determine whether the presence of an ulnar styloid fracture, the size or displacement of the fracture, or the healing status of the fracture was predictive of MHQ scores.

RESULTS

One-hundred and forty-four patients were enrolled; 88 patients had ulnar styloid fractures. During the collection period, DRUJ instability was found intraoperatively in 3 patients; these patients had ulnar styloid ORIF and were not enrolled. The 144 patients with a stable DRUJ after DRF ORIF maintained DRUJ stability after surgery. In these patients, the presence of an ulnar styloid fracture did not affect MHQ scores. Furthermore, the size of the ulnar styloid fracture, the degree of displacement, and the healing status of the ulnar styloid did not affect MHQ scores.

CONCLUSIONS

In patients with a stable DRUJ after DRF ORIF ulnar styloid fractures did not affect subjective outcomes as measured by the MHQ.

TYPE OF STUDY/LEVEL OF EVIDENCE

Prognostic III.

Relationship between patient satisfaction and objective functional outcome after surgical treatment for distal radius fractures

STUDY DESIGN

Prospective cohort.

INTRODUCTION

Patient satisfaction is increasingly used as a metric of health care outcomes. The relationship between patient satisfaction and functional outcomes metrics is understudied.

PURPOSE

To determine the minimum recovery needed in grip strength, key pinch strength, and arc of motion needed for patient satisfaction after treatment of distal radius fracture (DRF) with volar locking plating system placement.

METHODS

A prospective cohort of 125 DRF patients was evaluated three months after surgery for grip strength, key pinch strength, wrist arc of motion, and satisfaction with hand strength and wrist arc of motion. Receiver operating characteristic curves were constructed using patient satisfaction items as the "gold standard" and each functional measure of outcome as a predictor.

RESULTS

We found that the optimal cutpoints to distinguish satisfaction from dissatisfaction occurred when patients had recovered 65% of their grip strength, 87% of their key grip strength, and 95% of the wrist arc of motion, as measured as percents of their uninjured wrists.

CONCLUSIONS

A much greater wrist range of motion must be recovered for patients to be satisfied than what is needed to perform activities of daily living.

LEVEL OF EVIDENCE

Diagnosis level 2.

The minimal clinically important difference of the Michigan hand outcomes questionnaire

PURPOSE

To determine the change in score required in various domains of the Michigan Hand Outcomes Questionnaire (MHQ) to indicate meaningful patient improvement, or the minimal clinically important difference (MCID), for 3 common hand conditions: rheumatoid arthritis (RA), carpal tunnel syndrome (CTS) and distal radius fracture (DRF).

METHODS

The MHQ was administered to patients at 2 time points. Patient satisfaction was defined as a satisfaction score > or =80% of the standard deviation of that patient sample. The minimal change in score in specific MHQ domains that corresponded with patient satisfaction was determined using receiver operating characteristic curves.

RESULTS

For CTS patients, MCIDs of 23, 13, and 8 were identified for the pain, function, and work domains, respectively. For RA patients, pain and function were also identified as having discriminative ability, with MCIDs of 11 and 13, respectively. An MCID of 3 was identified for the activities of daily living domain. For DRF patients, no MHQ domains showed discriminative ability because of the ceiling effect at the 3-month assessment period.

CONCLUSIONS

Individual domains of the MHQ can be used to discriminate between patients who are satisfied and those who are not after either carpal tunnel release or silicone arthroplasty of the metacarpophalangeal joints for RA. Pain and function are the domains of the MHQ that are best able to discriminate between patients who are satisfied and those who are not. The identical function MCID for both RA patients and CTS patients, despite markedly different preoperative values, indicates that a standard amount of functional change may indicate patient satisfaction. High postoperative satisfaction, even only 3 months after surgery, prevented any domains from showing discriminative ability for the DRF patients.

Treatment of distal radius fractures with percutaneous pinning and pin-in-plaster

This article describes a modified technique that combines percutaneous pinning and casting. A prospective study was conducted on 54 patients with distal radius fracture who were treated with percutaneous Kirschner wire (K-wire) fixation and pin-in-plaster technique. The surgical indications of this technique included displaced extra-articular fracture, intra-articular fracture without significant comminution, and articular step-off less than 2 mm. The average radial height was 10.96 mm, and the volar tilt was 3.97 degrees on immediate postoperative radiographs. Upon removal of pin-in-plaster and percutaneous K-wires, the average radial height was 9.92 mm, and the volar tilt was 3.93 degrees . Bony union was achieved in all patients; the satisfaction rate was 90.7%. Pin-in-plaster technique is effective for maintaining reduction during bone healing. The procedure provides the ability to achieve anatomic reduction and then maintains this reduction through an adequate method of immobilization.

Retrospective comparison of percutaneous fixation and volar internal fixation of distal radius fractures

A change in the practice of a single surgeon provided an opportunity for retrospective comparison of comparable cohorts treated with percutaneous fixation (17 patients) or a volar plate and screws (23 patients) an average of 30 months after surgery. The final evaluation was performed according to the Gartland and Werley and Mayo rating systems and the DASH questionnaire. There were no significant differences on the average scores for the percutaneous and volar plating groups, respectively: Gartland and Werley, 4 vs 5; Mayo, 82 vs 83; and DASH score 13 for both cohorts. Motion, grip, and radiographical parameters were likewise comparable. Volar internal plate and screw fixation can achieve results comparable to percutaneous fixation techniques in the treatment of fractures of the distal radius.

Biomechanical comparison of different volar fracture fixation plates for distal radius fractures

The purpose of this study was to compare the biomechanical properties of four volar fixed-angle fracture fixation plate designs in a novel sawbones model as well as in cadavers. Four volar fixed angle plating systems (Hand Innovations DVR-A, Avanta SCS/V, Wright Medical Lo-Con VLS, and Synthes stainless volar locking) were tested on sawbones models using an osteotomy gap model to simulate a distal radius fracture. Based on a power analysis, six plates from each system were tested to failure in axial compression. To simulate loads with physiologic wrist motion, six plates of each type were then tested to failure following 10,000 cycles applying 100N of compression. To compare plate failure behavior, two plates of each type were implanted in cadaver wrists and similar testing applied. All plate constructs were loaded to failure. All failed with in apex volar angulation. The Hand Innovations DVR-A plate demonstrated significantly more strength in peak load to failure and failure after fatigue cycling (p value < 0.001 for single load and fatigue failure). However, there was no significant difference in stiffness among the four plates in synthetic bone. The cadaveric model demonstrated the same mode of failure as the sawbones. None of the volar plates demonstrated screw breakage or pullout, except the tine plate (Avanta SCS/V) with 1 mm of pullout in 2 of 12 plates. This study demonstrates the utility of sawbones in biomechanical testing and indicates that volar fixation of unstable distal radius fractures with a fixed angle device is a reliable means of stabilization.

Biomechanical evaluation of volar locking plates for distal radius fractures

PURPOSE

Fixed-angle devices have been a major advancement in orthopedic fracture care and have become an attractive option for fixation of distal radius fractures. Several volar locking plates exist, but there is insufficient literature comparing the strengths of these plates. This study compares the biomechanical strength of two popular volar locking plate systems (Synthes LCP and Hand Innovations DVR-A) along with a nonlocking volar T-plate (Synthes).

METHODS

Twenty-three formalin-fixed cadaveric forearms were divided into three groups with similar ages and bone densities. An unstable extra-articular fracture was created using a standardized osteotomy. Each group was fixed with one of the three plates. Each specimen was loaded in axial compression for 2000 cycles at a force of 400 N. Each specimen that completed cyclic testing was loaded to failure. Stiffness, yield point, and ultimate strength were recorded for each construct.

RESULTS

Each fixed-angle construct completed all 2000 cycles. The nonlocking plates failed at an average of 560 cycles. The mean stiffness of the DVR-A, LCP, and the volar T-plates were 277.00, 343.17, and 175.67 N/mm, respectively. There was a statistically significant difference between both fixed-angle plates and the nonlocking plate (p < 0.05). The difference between each fixed-angle construct did not reach significance. Yield point and ultimate strength could only be determined for the two fixed-angle devices. There was no statistically significant difference between the constructs for both yield point (DVR-A = 855.56 N, LCP = 894.15 N) and ultimate strength (DVR-A = 1,021.97 N, LCP = 1,114.87 N).

CONCLUSIONS

Given our data, fixed-angle constructs withstand cyclical loading representing normal physiologic forces encountered during post-operative rehabilitation. There was no significant biomechanical difference between the two fixed-angle constructs. Our results support that volar fixed-angle locking plates are an effective treatment for unstable extra-articular distal radius fractures, allowing early postoperative rehabilitation to safely be initiated.

"Sandwich" plating for intra-articular distal radius fractures with volar and dorsal metaphyseal comminution

INTRODUCTION

Intra-articular distal radius fractures with volar and dorsal comminution present a special challenge to the hand surgeon.

METHODS

Ten patients formed the study cohort. All plates were low profile and stainless steel. Radiographic parameters, range of motion, and strength compared to the uninjured side were recorded. Functional outcome was evaluated by Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and Gartland and Werley scoring system.

RESULTS

Median age at surgery was 58 years (range, 24 to 86). Mean follow-up was 17 months (range, 12 to 28). According to the AO classification system, there were three type C2 and seven type C3 fractures. Median preoperative dorsal angulation was 24 deg; median postoperative dorsal angulation was 3 deg. Eighty percent (8) of the fractures also had an intra-articular step-off or gap, all of which were corrected to neutral by the procedure. Compared with the contralateral side, mean extension and flexion were 73 and 75%, respectively, pronation and supination were 95 and 88%, respectively, and grip strength and thumb pinch were 72 and 87%, respectively. Mean postoperative DASH score was 16 points, and 70% (7) of the patients had Gartland and Werley scores of good or excellent. None of the patients needed to have their plates removed, and no extensor tendon rupture was reported.

CONCLUSIONS

The "sandwich" plating technique is an effective method of regaining near-anatomic reconstruction of intra-articular, volarly and dorsally comminuted distal radius fractures. Results from this study demonstrate that patients can expect to regain about 80% of their range of motion and strength. Moreover, 70% of the patients will have good to excellent functional outcomes. This is the first study to examine range of motion and functional outcome of low-profile "sandwich" plating without plate removal.

Comparative outcomes study using the volar locking plating system for distal radius fractures in both young adults and adults older than 60 years

PURPOSE

Despite the high prevalence and impact of distal radius fractures (DRFs) on older patients, the currently available literature regarding DRFs in older adults lacks adequate comparative treatment data. The purpose of this prospective, controlled outcomes study is to compare outcomes using the volar locking plating system (VLPS) for DRFs in both older and younger adults and to assert the eligibility of older patients for surgical management with the VLPS.

METHODS

Consecutive, eligible patients were enrolled into our prospective study over a 2-year period on the basis of strict inclusion and exclusion criteria. Subjects were entered into 2 cohorts based on age: 20-40 years and >60 years. Patient outcomes and complication rates were evaluated at 3, 6, and 12 months after surgery. Outcome measures included the Michigan Hand Outcomes Questionnaire (MHQ), grip strength, active wrist and forearm range of motion, the Jebsen-Taylor test, and radiographic parameters.

RESULTS

Fifty-five patients (30 young and 25 older adults) with unilateral, inadequately reduced DRFs were enrolled and received surgical treatment with the VLPS. We observed no statistically significant difference in any of the outcomes for all 3 follow-up periods, except the Jebsen-Taylor test, which displayed a trend toward a worse outcome in the older-age cohort. Whereas older patients continued to improve throughout their 12-month postoperative visits, younger patients achieved their maximum recovery during the 6-month follow-up period, suggesting different recovery patterns. At the 12-month assessment, older patients were able to achieve a higher mean MHQ score than their younger counterparts (normalized mean: 85% and 82%, respectively). Complication rates were similar between the 2 groups for all 3 time periods, with most occurring on or before the 3-month postoperative visit.

CONCLUSIONS

This study indicates that the VLPS is successful in managing DRFs in older patients without increased complications compared to younger patients. For older patients without prohibitive surgical risks, internal fixation using the VLPS yields comparable outcomes to younger patients. However, these conclusions do not necessarily apply to other surgical techniques used to manage DRFs in older adults.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic II.