Trapezium trabecular morphology in carpometacarpal arthritis.

PURPOSE: In thumb carpometacarpal osteoarthritis, current evidence suggests that degenerative, bony remodeling primarily occurs within the trapezium. Nevertheless, the pathomechanics involved and the most common sites of wear remain controversial. Quantifying structural bone morphology characteristics with high-resolution computed tomography CT (micro-CT) infer regions of load transmission. Using micro-CT, we investigated whether predominant trabecular patterns exist in arthritic versus normal trapeziums. METHODS: We performed micro-CT analysis on 13 normal cadaveric trapeziums and 16 Eaton stage III to IV trapeziums. We computationally divided each specimen into 4 quadrants: volar-ulnar, volar-radial, dorsal-radial, and dorsal-ulnar. Measurements of trabecular bone morphologic parameters included bone volume ratio, connectivity, trabecular number, and trabecular thickness. Using analysis of variance with post hoc Bonferroni/Dunn correction, we compared osteoarthritic and normal specimen quadrant measurements. RESULTS: No significant difference existed in bone volume fraction between the osteoarthritic and normal specimens. Osteoarthritic trapeziums, however, demonstrated significantly higher trabecular number and connectivity than nonosteoarthritic trapeziums. Comparing the volar-ulnar quadrant of osteoarthritis and normal specimens collectively, this quadrant in both consistently possessed significantly higher bone volume fraction, trabecular number, and connectivity than the dorsal-radial and volar-radial quadrants. CONCLUSIONS: The significantly greater trabecular bone volume, thickness, and connectivity in the volar-ulnar quadrant compared with the dorsal-radial and dorsal-ulnar quadrants provides evidence that the greatest compressive loads at the first carpometacarpal joint occur at the volar-ulnar quadrant of the trapezium, representing a consistently affected region of wear in both normal and arthritic states. CLINICAL RELEVANCE: These findings suggest that trapezial trabecular morphology undergoes pathologic alteration. This provides indirect evidence that changes in load transmission occur with thumb carpometacarpal joint arthritis development.

The influence of gravity on the unstable elbow.

BACKGROUND: Safely permitting early range of motion after a destabilizing injury to the elbow is believed to optimize return of function. However, the range-of-motion exercises must be balanced against the risk of re-dislocation or subluxation. The goal of this study was to describe the position of the upper limb that permitted the greatest motion while minimizing the risk of re-dislocation or subluxation. METHODS: Seven cadaveric elbows were affixed with a 3-dimensional motion capture system. Ulnohumeral distraction was recorded at flexion angles from 10° to 90° for intact, approach only (sham procedure), and LCL-sectioned. Ulnohumeral separation was recorded in 3 distinct positions of the upper limb that are frequently used in a clinical setting: 1) trunk seated upright with arm at the side; 2) trunk seated upright with elbow in hinged-brace; and 3) trunk supine with shoulder flexed and internally rotated - "gravity-assisted overhead motion" protocol. RESULTS: A significant ulnohumeral distraction difference was found between the supine and the upright protocols. Upon direct comparison, 104% more displacement occurred across the ulnohumeral joint in the upright LCL-sectioned condition compared to the supine LCL-sectioned condition (P = .001). The greatest ulnohumeral distraction occurred in the seated upright range of motion with a hinged elbow brace (range, 2.5-5.6 mm). CONCLUSION: The overhead motion protocol is a safe protocol for unstable elbows. The supine position results in the least amount of ulnohumeral distraction across flexion angles from 10° to 90°. The upright protocols, especially with the hinged elbow brace, exhibited ulnohumeral distraction that may result in dislocation.

All-arthroscopic repair of Palmer 1B triangular fibrocartilage complex tears using the FasT-Fix device.

PURPOSE: The FasT-Fix device (Smith and Nephew Endoscopy, Andover, MA), initially developed for knee meniscal tears, is described for all-arthroscopic triangular fibrocartilage complex (TFCC) repairs. Potential benefits of this technique are ease of use, the lack of prominent suture knots, and strength of repair. This case series evaluates the early clinical outcomes of this technique. METHODS: We conducted a retrospective review of patients with TFCC Palmer type 1B injuries treated by 1 hand surgeon from 2005 to 2009. The patients' charts were reviewed for postoperative complications, range of motion, grip strength (percentage of contralateral), and return to full activity. In addition, each patient completed Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH) and Patient-Rated Wrist Evaluation (PRWE) questionnaires. RESULTS: Twelve patients had all-arthroscopic peripheral (1B) TFCC repairs using the FasT-Fix suture device. The mean follow-up period was 17.5 months (range, 11-27). Mean supination was 78° (± 14°), and mean grip strength was 64% (±16%) of the nonsurgical extremity by 3 months after surgery. All other range of motion was full. The mean QuickDASH score was 11 (±12), and the mean PRWE score was 19 (±14). Average time to full activity was 5 months. There were no surgical complications of the procedure. One patient complained of persistent ulnar-sided wrist pain 12 months after surgery and had an ulnar shortening osteotomy. Arthroscopy at the time of the osteotomy revealed that the TFCC was stable. CONCLUSIONS: At mean 1-year follow-up, 11 out of 12 patients achieved excellent subjective outcomes based on QuickDASH and PRWE questionnaires. Although range of motion and grip strength were slightly decreased compared to prior case series reports, the short-term results indicate that the FasT-Fix all-arthroscopic, all-inside technique is a safe and effective technique for repair of Palmer type 1B TFCC tears.

Foreign-body reaction and osteolysis induced by an intraosseous poly-L-lactic Acid suture anchor in the wrist: case report.

Polyglycolic acid and poly-L-lactic acid have become popular choices for bioabsorbable anchor fixation in the hand and wrist. We report a case of osteolysis, synovitis, and chondral erosion secondary to a poly-L-lactic acid suture anchor in the wrist.

Biomechanical comparison of blade plate and intramedullary nail fixation for tibiocalcaneal arthrodesis.

BACKGROUND: Tibiocalcaneal arthrodesis is an uncommon salvage procedure used for complex problems of the ankle and hindfoot. A biomechanical evaluation of the fixation constructs of this procedure has not been studied previously. The purpose of this study was to compare intramedullary nail to blade plate fixation in a deformity model in fatigue endurance testing and load to failure. MATERIALS AND METHODS: Nine matched pairs of fresh frozen cadaveric legs underwent talectomy followed by fixation with a blade plate and 6.5-mm fully threaded cancellous screw or an ankle arthrodesis intramedullary nail. The specimens were loaded to 270 N at a rate of 3 Hz for a total of 250,000 cycles, followed by loading to failure. RESULTS: Intramedullary nail fixation demonstrated greater mean stiffness throughout the fatigue endurance testing, from cycles 10 through 250,000 (blade plate versus intramedullary nail; cycle 10, 93 +/- 34 N/mm versus 117 +/- 40 N/mm (t = 2.33, p = 0.04); cycle 100, 89 +/- 34 N/mm versus 118 +/- 42 N/mm (t = 3.16, p = 0.01); cycle 1000, 86 +/- 32 N/mm versus 120 +/- 45 N/mm (t = 3.52, p = 0.01); cycle 10,000, 83 +/- 36 N/mm versus 128 +/- 50 N/mm (t = 3.80, p = 0.01); cycle 100,000, 82 +/- 34 N/mm versus 126 +/- 52 N/mm (t = 3.70, p = 0.01); cycle 250,000, 80 +/- 31 N/mm versus 125 +/- 49 N/mm (t = 4.2, p = 0.003). There was no statistically significant difference between the intramedullary nail and blade plate fixation in cycle one or in load to failure; cycle 10, blade plate 70 +/- 38 N/mm and intramedullary nail 67 +/- 20 N/mm (t = 0.60, p = 0.56); load to failure, blade plate 808 +/- 193 N, IMN 1074 +/- 290 N) (p = 0.15). CONCLUSION: Intramedullary nail fixation was biomechanically superior to blade plate and screw fixation in a tibiocalcaneal arthrodesis construct. CLINICAL RELEVANCE: The ankle arthrodesis intramedullary nail provides greater stiffness for fixation in tibiocalcaneal arthrodesis, which may improve healing.

Two ulnar collateral ligament reconstruction methods: the docking technique versus bioabsorbable interference screw fixation--a biomechanical evaluation with cyclic loading.

We compared the effects of cyclic valgus loading on 2 techniques for reconstruction of the elbow ulnar collateral ligament (UCL): the docking procedure and the bioabsorbable interference screw procedure. A cyclic valgus load was applied to the 16 unembalmed elbows, and the valgus angle was measured at 1, 10, 100, and 1000 cycles. Testing was repeated after UCL palmaris tendon reconstruction via either the docking technique or bioabsorbable interference screw fixation. At cycle 1, the valgus angle was not different between treated and intact cases. At cycles 10 and 100, the valgus angle for the docking technique was significantly greater than that for both the intact cases and the interference screw technique. By the 1000th cycle, no difference was measured between the 2 techniques. In this study, bioabsorbable interference screw fixation resulted in less valgus angle widening in response to early cyclic valgus load as compared with the docking technique.

Acute compartment syndrome of the thigh in a football athlete: a case report and the role of the vacuum-assisted wound closure dressing.

We present a case of compartment syndrome of the thigh due to blunt injury in a Division I American football player managed with fasciotomy and vacuum-assisted wound closure. This case report discusses the vacuum-assisted wound closure dressing as an alternative to more traditional closure techniques such as suture retention devices and split-thickness skin grafting. We feel that any surgeon involved in performing fasciotomies should be familiar with this increasingly used closure device and its potential complications.

Thumb metacarpophalangeal joint collateral ligament injury management.

The thumb collateral ligaments at the metacarpophalangeal joint are important to the elite athlete for precision grip and pinch. Injuries to these ligaments can result in pain and instability and are seen at a higher frequency at the elite level. Whereas the collateral ligament tears used to be associated primarily with recreational skier's injury, these injuries have been reported with increasing frequency in major professional sports. The ulnar collateral and radial collateral ligament injuries of the thumb occur through different mechanisms and are described in separate sections given the differences in their anatomy.

Treatment of thumb carpometacarpal arthritis with arthroscopic hemitrapeziectomy and interposition arthroplasty.

The carpometacarpal joint of the thumb is a common site of degenerative arthritis. Several surgical treatments exist, but arthroscopic management offers the potential benefit of earlier recovery. The current study evaluated the early clinical outcomes of a procedure involving arthroscopic hemitrapeziectomy with Artelon spacer (Artimplant, Västra Frölunda, Sweden) interposition arthroplasty into the newly created carpometacarpal space.A chart review of 9 patients treated with thumb carpometacarpal arthroscopic hemitrapeziectomy and Artelon spacer interposition arthroplasty between September 2005 and January 2009 was performed for postoperative complications, range of motion, and pinch strength (percentage of the contralateral limb). Subjective outcomes were analyzed by the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire and the Patient-rated Wrist Evaluation. Mean follow-up was 23.4 months (range, 13-33 months). All patients maintained full range of motion. By the 1-year follow-up, mean pinch strength returned to 59%± 19.1% of the contralateral limb strength. The Quick Disabilities of the Arm, Shoulder, and Hand and the Patient-rated Wrist Evaluation scores were 12.3 ± 7.6 and 26.8 ± 23.5, respectively. No significant complications occurred, and 1 patient with symptoms of synovitis was successfully treated with a corticosteroid injection. This study revealed excellent short-term results at the minimum 1-year follow-up for a less invasive treatment option that is appropriate for select patients with moderate thumb carpometacarpal arthritis (Eaton stages 2 and 3). The authors demonstrated a comparably good outcome of arthroscopic hemitrapeziectomy with Artelon spacer interposition arthroplasty with no evidence of foreign-body reaction. The authors also demonstrated the potential role of corticosteroid injections in the setting of a postoperative inflammatory reaction.

Osteochondral lesions of the talus: effect of defect size and plantarflexion angle on ankle joint stresses.

BACKGROUND: Osteochondral lesions of the talus (OLTs) are a common cause of ankle pain and disability. Current clinical guidelines favor autogenous or allogenic osteochondral grafting procedures for lesions larger than 10 mm in diameter because of increased failure rates in these larger lesions with arthroscopic debridement, curettage, and microfracture. There are currently no biomechanical data nor level I clinical data supporting this size threshold. PURPOSE: The purpose of this study was to determine the effect of OLT defect size on stress concentration, rim stress, and location of peak stress and whether a threshold defect size exists. STUDY DESIGN: Descriptive laboratory study. METHODS: Progressively larger medial OLTs were created (6, 8, 10, and 12 mm) in 8 fresh-frozen cadaveric ankle joints. With a calibrated Tekscan pressure sensor in the tibiotalar joint, an axial load of 686 N was applied, and pressure was recorded in neutral and 15° of plantar flexion with each defect size. Peak stress, contact area, peak and average rim stresses, and location of peak stress were determined. RESULTS: The distance between peak stress and defect rim was significantly decreased with increasing defect size for lesions of 10 mm and larger. Total tibiotalar contact area was significantly decreased with increasing defect size and with ankle plantar flexion. While peak joint stress and peak rim stress were not affected by defect size or plantar flexion, average rim stress was significantly increased by plantar flexion. CONCLUSION: Reduction in contact area and shift in the location of peak stress with increasing defect size may contribute to articular cartilage degeneration, pain, and defect enlargement in patients with OLTs. There appears to be a threshold of 10 mm after which the distance between the rim of the defect and the peak stress decreases; however, there is no change in peak stress magnitude with increasing defect size. CLINICAL RELEVANCE: The location of peak stress in the ankle joint becomes closer to the rim of the defect in OLTs at a threshold of 10 mm and greater in diameter. These data may have implications toward OLT size thresholds for surgical decision making in symptomatic lesions (ie, primary osteochondral transplantation procedure vs curettage and debridement). The ultimate goal is to determine whether there is a threshold defect size for primary osteoarticular graft techniques.

Single column locking plate fixation is inadequate in two column acetabular fractures. A biomechanical analysis.

BACKGROUND: The objective of this study was to determine whether one can achieve stable fixation of a two column (transverse) acetabular fracture by only fixing a single column with a locking plate and unicortical locking screws. We hypothesized that a locking plate applied to the anterior column of a transverse acetabular fracture would create a construct that is more rigid than a non-locking plate, and that this construct would be biomechanically comparable to two column fixation. METHODS: Using urethane foam models of the pelvis, we simulated transverse acetabular fractures and stabilized them with 1) an anterior column plate with bicortical screws, 2) an anterior locking plate with unicortical screws, 3) an anterior plate and posterior column lag screw, and 4) a posterior plate with an anterior column lag screw. These constructs were mechanically loaded on a servohydraulic material testing machine. Construct stiffness and fracture displacement were measured. RESULT AND DISCUSSION: We found that two column fixation is 54% stiffer than a single column fixation with a conventional plate with bicortical screws. There was no significant difference between fixation with an anterior column locking plate with unicortical screws and an anterior plate with posterior column lag screw. We detected a non-significant trend towards more stiffness for the anterior locking plate compared to the anterior non-locking plate. CONCLUSION: In conclusion, a locking plate construct of the anterior column provides less stability than a traditional both column construct with posterior plate and anterior column lag screw. However, the locking construct offers greater strength than a non-locking, bicortical construct, which in addition often requires extensive contouring and its application is oftentimes accompanied by the risk of neurovascular damage.

Bone cement improves suture anchor fixation.

Suture anchor fixation failure can occur if the anchor pulls out of bone. We hypothesized that suture anchor fixation can be augmented with polymethylmethacrylate cement, and that polymethylmethacrylate can be used to improve fixation in a stripped anchor hole. Six matched cadaveric proximal humeri were used. On one side, suture anchors were placed and loaded to failure using a ramped cyclic loading protocol. The stripped anchor holes then were injected with approximately 1 cc polymethylmethacrylate, and anchors were replaced and tested again. In the contralateral humerus, polymethylmethacrylate was injected into anchor holes before anchor placement and testing. In unstripped anchors, polymethylmethacrylate increased the number of cycles to failure by 34% and failure load by 71% compared with anchors not augmented with polymethylmethacrylate. Polymethylmethacrylate haugmentation of stripped anchors increased the cycles to failure by 31% and failure load by 111% compared with unstripped uncemented anchors. No difference was found in cycles to failure or failure load between cemented stripped anchors and cemented unstripped anchors. Polymethylmethacrylate can be used to augment fixation, reducing the risk of anchor pull-out failure, regardless whether the suture anchor hole is stripped or unstripped.