Biomechanical Analysis of All-Inside, Arthroscopic Suture Repair Versus Extensor Retinaculum Capsulorrhaphy for Triangular Fibrocartilage Complex Tears With Instability.

PURPOSE: To assess ulnocarpal joint stability after treatment of a peripheral triangular fibrocartilage complex (TFCC) injury with all-inside arthroscopic suture repair (SR), extensor retinaculum capsulorrhaphy with the Herbert sling (HS), and a combination of both (SR+HS). METHODS: Twelve fresh-frozen, age-matched, upper-extremity specimens intact from the distal humerus were prepared. Nondestructive mechanical testing was performed to assess native ulnocarpal joint stability and load-displacement curves were recorded. A peripheral, ulnar-sided TFCC injury was created with arthroscopic assistance, and mechanical testing was performed. Each specimen was treated with SR or HS and testing was repeated. The 6 specimens treated with SR were then treated with HS (SR+HS), and testing was repeated. We used paired Student t tests for statistical analysis within cohorts. RESULTS: For all cohorts, there was an average increase in ulnar translation after the creation of a peripheral TFCC injury and an average decrease after repair. Herbert sling decreased translation by 21%, SR decreased translation by 12%, and SR+HS decreased translation by 26%. CONCLUSIONS: Suture repair plus HS and HS reduce ulnar translation the most after a peripheral TFCC injury, followed by SR alone. CLINICAL RELEVANCE: Ulnocarpal joint stability should be assessed clinically in patients with peripheral TFCC injury, and consideration should be made for using extensor capsulorrhaphy in isolation or as an adjunct to SR as a treatment option.

Peripheral triangular fibrocartilage complex tears cause ulnocarpal instability: a biomechanical pilot study.

BACKGROUND: Instability at the ulnocarpal joint has many causes, but the common thread among these causes is the presence of abnormalities in the triangular fibrocartilage complex (TFCC). However, the biomechanical consequences at the ulnocarpal joint after detachment of the TFCC from the ulnar styloid are not clearly defined. Better delineation of whether peripheral TFCC detachments cause ulnocarpal instability will help to design surgical treatments. QUESTIONS/PURPOSES: We asked whether detachment of the peripheral TFCC from the ulnar styloid causes ulnocarpal instability. METHODS: Using 20 fresh-frozen below-elbow cadaver specimens, the distal ulna was cycled volarly and dorsally with the carpus held firmly. The load-displacement curve was analyzed to determine the resistance of the ulnocarpal joint against dorsal-volar displacement of the ulna (stiffness) and the amount of dorsal-volar excursion with minimal resistance before reaching firm end points dorsally and volarly. A standardized 3-mm transection of the attachment of the TFCC from the ulnar styloid was created with a scalpel using arthroscopic observation. Mechanical testing was repeated and paired Student's t-tests conducted. RESULTS: The mean stiffness of the ulnocarpal joint was decreased after detachment. The amount of dorsal-volar excursion was similar after detachment of the peripheral TFCC. CONCLUSIONS: There is decreased stiffness at the ulnocarpal joint after detachment of the peripheral TFCC, but there is no biomechanically detectable difference in dorsal-volar excursion. CLINICAL RELEVANCE: The findings of the current study can be used to develop and evaluate innovative surgical techniques, such as capsulorraphy or ligamentous reconstruction, that specifically address laxity at the ulnocarpal joint after peripheral TFCC detachment.

Comparison of 2 forearm reconstructions for longitudinal radioulnar dissociation: a cadaver study.

PURPOSE: We present the results of a cadaveric study of 2 forearm reconstructions with radial head replacement for longitudinal radioulnar dissociation injuries. METHODS: We created a simulated longitudinal radioulnar dissociation injury in 8 cadaver forearms. Two reconstructions were performed alternately on each arm: patellar tendon interosseous ligament complex reconstruction and the Herbert sling extensor retinaculum plication. We performed mechanical testing in a materials testing machine with and without a radial head replacement, and measured ulnocarpal impaction force through 2 distal ulna strain gauges. We determined relative radioulnar displacement using live fluoroscopic analysis of implanted stainless-steel beads. RESULTS: Relative radioulnar longitudinal displacement in the destabilized forearms was 10.7 compared with 0.7 mm before creating the injury. A prosthetic radial head replacement alone decreased the displacement by 75% to 2.7 mm. Interosseous ligament reconstruction alone reduced the displacement to 5.1 mm and to 1.3 mm when combined with a radial head implant. The Herbert sling alone did not improve longitudinal stability. The distal ulna force in the native arm was 17 N, or 17% of the force across the wrist. The interosseous ligament reconstruction restored the force to 21 N, whereas the Herbert sling only marginally decreased the ulna impaction force to 45 N. Adding a radial head decreased the distal ulna force to 7 N for the patellar tendon interosseous ligament reconstruction, and 2 N for the Herbert sling. CONCLUSIONS: In longitudinal radioulnar dissociation injuries, the radial head is an important stabilizer and should be repaired or replaced to minimize radial shortening and ulnar impaction force. Patellar tendon interosseous ligament reconstruction effectively restores the ulnocarpal force distribution and markedly reduces longitudinal instability at the distal radioulnar joint. Combined with radial head arthroplasty, the construct has stability similar to an intact forearm. The Herbert sling did not improve longitudinal stability in this testing construct. CLINICAL RELEVANCE: Treatment of longitudinal radioulnar dissociation may benefit from radial head replacement and interosseous ligament reconstruction using a patellar tendon graft.

Suture-button construct for interosseous ligament reconstruction in longitudinal radioulnar dissociations: a biomechanical study.

PURPOSE: Longitudinal radioulnar dissociation is a triad of injuries consisting of distal radioulnar joint disruption, interosseous ligament complex (IOLC) tear, and radial head fracture. This renders the forearm longitudinally unstable, resulting in proximal migration of the radius and ulnar-sided wrist degeneration. We hypothesized that reconstruction of the central band of the IOLC in cadaver forearms using a Mini-TightRope suture-button construct would restore native forearm stability. METHODS: We implanted 8 fresh-frozen cadaver arms with steel beads into the distal radius and ulna, mounted them on an MTS machine, and cyclically loaded them from 13 N distraction to 130 N compression. Bead motion was recorded fluoroscopically and analyzed using Image-Pro Express software. We measured distal ulnar forces using strain gauge transducers. Longitudinal radioulnar dissociation injuries were created by radial head excision and complete IOLC and triangular fibrocartilage complex disruption. At each stage, arms were tested with and without a radial head implant. We reconstructed the central band of the IOLC using a Mini-TightRope and tightened until the distal radioulnar joint was reduced fluoroscopically. We used multiple-comparison analysis of variance with Tukey's Honestly Significant Difference test for statistical analysis. RESULTS: The intact arms had an average radioulnar axial displacement of 0.7 ± 0.8 mm and distal ulnar impaction force of 16.7 ± 11.1 N (per 100 N of axial load on the forearm). After destabilization, the radioulnar displacement increased to 10.7 ± 3.9 mm (p < .001) and ulnar load increased 312%, to an average of 52.2 ± 25.7 N (p < .001). After IOLC reconstruction, average displacement decreased to 2.2 ± 0.9 mm with a distal ulnar load of 19.05 ± 13.5 N (not significantly different from intact arms). CONCLUSIONS: In this cadaveric study, Mini-TightRope IOLC reconstruction with or without a radial head prosthesis significantly reduced distal ulnar impaction forces to that of the native forearm, while limiting radioulnar displacement to near-anatomic levels.

Infected nonunions of diaphyseal fractures of the forearm.

BACKGROUND: There are no reported series that specifically deal with repair of infected nonunions of the diaphysis of the forearm bones. We sought to determine whether a standardized treatment protocol we have utilized for 15 patients from 1989 to 2005 results in a high union rate, resolution of infection, and a good functional outcome. METHODS: The study cohort included nine male and six female patients who presented to a University hospital setting with an infected nonunion of the diaphysis of the radius or ulna. Every patient had a minimum of 2-year follow-up. The average patient age was 45 years (range 17-79). Eight of the patients had fractures involving their dominant arm. Thirteen patients had initially fractured both the radius and ulna, but two of these patients had subsequently healed one of the bones. One patient had an isolated radius fractures, and one patient fractured the ulna alone. All patients underwent a protocol that combines aggressive surgical debridements as necessary, definitive fixation after 7-14 days, tricortical iliac crest bone grafting for segmental defects, leaving wounds open to heal by secondary intention, 6 weeks of culture-specific intravenous antibiotics, and early active range of motion (ROM) exercises. We sought to report our success rate of nonunion repair, number of re-interventions, complication rate, final ROM, and the ability to eradicate the infection using this treatment regimen. RESULTS: At most recent follow-up (average 5 years, range 2-15 years), all patients had united and resolved their infections. One case was considered a failure, although he did go on to unite a one-bone forearm and was free of infection at most recent follow-up. All but three patients, including the one failure, had at least 50 degrees of supination/pronation and 30-130 degrees of flexion/extension arc. Excluding the one failure that united his one-bone forearm at 46 months, the average time to union was 13.2 weeks (range 10-15 weeks). CONCLUSIONS: The results of this study indicate that our standard protocol for treatment of infected nonunion of the shafts of the radius and ulna is reliable at obtaining fracture union with a good functional result, while also resolving the infection.

How men and women are affected by osteoarthritis of the hand.

Factors other than age and genetics may play a role in explaining the onset of osteoarthritis of the hand. Genetic, physiologic, and anatomic differences in men and women cause the variable expressions of osteoarthritis. These different factors affect women's ability to modify osteoarthritis of the hand before and after its onset, although it is genetic. By maintaining normal weight, good health, and nutrition, one can diminish the genetic and multifactorial effects of osteoarthritis of the hand. Future research in genetics, polymorphism, anatomy, hormonal influences, association with other disease processes, and multifactorial issues will clarify these relationships. Additional studies are needed to investigate the outcomes of gender-specific treatments, joint replacement surgery, and other interventions for osteoarthritis of the hand.