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Purpose: To evaluate the effect of ulnar shortening on distal forearm loading following simulated dynamic motion., Methods: Ulnar shortening was simulated using a custom-built adjustable implant to simulate up to 4 mm of ulnar shortening (-4 mm) in 9 cadaveric extremities. Load cells were placed in the distal ulna and radius to quantify axial loading. Using a wrist and forearm motion simulator, absolute and percentage loads were measured during dynamic flexion, ulnar deviation (UD), flexion dart throw (DT), and pronation., Results: There was a significant decrease in absolute and percentage distal ulnar loads at each interval of ulnar shortening during flexion, UD, DT, and pronation. The distal ulna bore no compressive loads, and in fact, tensile loads were measured in the ulna at 2 mm of ulnar shortening during DT and pronation, at 3 mm during flexion, and at 4 mm during UD., Conclusions: A progressive decrease in distal ulnar loads with generation of tensile loads was observed with sequential ulnar shortening., Clinical Relevance: Ulnar shortening greater than 2 mm can result in tensile loading in the distal ulna. When managing ulnar impaction syndrome, excessive shortening may not be required to provide relief of symptoms., (Copyright © 2019 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Chronic exertional compartment syndrome (CECS) refers to exercise-induced, reversible increases in pressure within well-defined inelastic fascial compartments leading to compromised tissue perfusion followed by functional loss, ischemic pain, and neurologic symptoms. Symptoms typically resolve when the activity ceases and there are usually no permanent sequelae. In the upper extremity, this condition most commonly affects athletes during sports requiring repetitive and vigorous gripping, such as rowers. In addition to clinical history and examination, a number of methods aid diagnosis, including compartment pressure measurements, magnetic resonance imaging, and near infrared spectroscopy. When symptoms persist despite conservative treatment, multiple operative techniques have been described to treat CECS including open, mini-open, and endoscopic release of involved compartments. We review the pathophysiology, diagnostic modalities, treatment strategies, and outcomes data for CECS of the upper extremity while highlighting areas of residual controversy., (Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: In nonsurgical treatment for acute undisplaced or minimally displaced scaphoid waist fractures, immobilization of both wrist and thumb can be an option. However, in vivo scaphoid motion during forearm and thumb motion with the wrist immobilized in a cast has not been measured. Therefore, we examined the in vivo kinematics of the scaphoid during forearm and thumb motion with cast immobilization., Methods: Ten healthy right wrists of 10 male volunteers were included. These wrists were immobilized in a short-arm spica cast with the thumb in a position of volar abduction and then were scanned with the forearm in supination, neutral rotation, and pronation using computed tomography. Next, these wrists were scanned with a forearm gauntlet cast in place with the thumb abducted radially and opposed with the forearm positioned in neutral rotation. From these data, the 3-dimensional position of the third metacarpal and scaphoid was analyzed., Results: From forearm supination to pronation, the scaphoid showed 0.2° radial deviation, 0.4° pronation, and 8.3° extension. The third metacarpal showed 14.6° ulnar deviation, 6.5° pronation, and 1.6° flexion. During thumb opposition from radial abduction, the scaphoid showed 2.9° radial deviation, 0.4° supination, and 7.2° extension and the third metacarpal showed 4.5° ulnar deviation, 2.8° pronation, and 5.5° extension., Conclusions: The scaphoid was not completely immobilized by either cast. However, the scaphoid motion during forearm and thumb motion was not significant., Clinical Relevance: Several high-quality studies have shown that undisplaced or minimally displaced scaphoid waist fractures can be successfully treated with casts. Movement of scaphoid and wrist during forearm rotation or thumb motion with a cast may not be sufficient to have a negative impact on the outcome of scaphoid fracture using a cast., (Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To examine the effect of volar angulation deformities of the distal radius with and without triangular fibrocartilage complex (TFCC) rupture on forearm range of motion and the kinematics of the ulnar head at the distal radioulnar joint (DRUJ) during simulated active forearm rotation., Methods: Volar angulation deformities of the distal radius with 10° and 20° angulation from the native orientation were created in 8 cadaveric specimens using an adjustable apparatus. Active supination and pronation were performed using a forearm motion simulator. Pronation and supination range of motion was quantified with each deformity. In addition, changes in the dorsovolar position of the ulnar head relative to the radius were calculated after simulating each distal radial deformity. Testing was performed with the TFCC intact and sectioned., Results: Volar angulation deformities of 20° decreased the supination range with preservation of pronation. There was no effect of TFCC status on the range of forearm rotation. With the TFCC intact, volar angulation deformities translated the ulna slightly dorsally in pronation and volarly in supination. After sectioning the TFCC, volar angulation deformities of 10° and 20° translated the ulna dorsally throughout forearm rotation., Conclusions: Volar angulation deformities reduce supination range and alter the DRUJ kinematics. The increased tension in the intact TFCC caused by volar angulation deformities likely prevented the expected dorsovolar displacement at the DRUJ and restricted supination. Dividing the TFCC released the constraining effect on the DRUJ and allowed the ulna to translate dorsally. However, supination remained limited, presumably because of impediment from the dorsally subluxated ulna., Clinical Relevance: This study demonstrated the importance of correcting volar angulation deformities of the distal radius to less than 20° in order to maintain normal range of forearm rotation and to less than 10° to maintain normal DRUJ kinematics when the TFCC is ruptured., (Copyright © 2015 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Management of elbow and forearm involvement in cerebral palsy has evolved over the last 3 decades with a better understanding of its neuropathophysiology, improved outcome measures, and evolving therapy protocols. Current nonoperative and surgical treatment methods are discussed. The use of standard function measuring instruments and encouragement of the participation in research will hopefully result in more accurate outcome information and, thereby, refine our techniques and rehabilitation methods., (Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To compare ranges of active forearm pronation and supination with subjects wearing short arm casts of different lengths., Materials and Methods: Forty right-handed healthy volunteers (20 men and 20 women) with an average age of 39 years (range, 26-58 y) were recruited. A goniometer with a circular plate and a handle connected to the scale indicator was used to measure forearm pronation and supination without a cast and with 3 different lengths of short arm cast. All casts extended from just proximal to the volar and dorsal aspects of metacarpophalangeal joints, and continued to either 2.5 cm distal to elbow flexion crease or 5 cm distal to the elbow flexion crease, or to the proximal one-third position between the wrist flexion crease and the elbow flexion crease., Results: Compared with no immobilization, the longest of the 3 constructs reduced active forearm rotation by 62%, whereas the cast to 5 cm from the elbow flexion crease reduced rotation to 50%, and the cast to the proximal one third of the way between the wrist and elbow flexion crease reduced rotation by 32%. Active forearm rotation was significantly dependent on cast length, and reductions in active forearm rotation were positively correlated with cast length., Conclusions: Limitation of active forearm rotation by a short arm cast is positively correlated with cast length., Clinical Relevance: When a short arm cast is used to limit wrist motion and forearm rotation, it is better to extend it proximally but not to impinge on the antecubital fossa, where skin breakdown may occur., (Copyright © 2014 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

A 39-year-old tetraplegic patient had paralysis of elbow, thumb, and finger extension and thumb and finger flexion. We transferred axillary nerve branches to the triceps long and upper medial head motor branches, supinator motor branches to the posterior interosseous nerve, and brachioradialis tendon to the flexor pollicis longus and flexor superficialis of the index finger. Surgery was performed bilaterally 18 months after spinal cord injury. At 12 months after surgery, we performed bilateral distal radioulnar arthrodesis percutaneously. By 22 months postoperatively, we observed triceps strength scoring M3 bilaterally and full metacarpophalangeal joint extension scoring M4 bilaterally. The thumb span was 53 and 66 mm from the proximal index phalanx on the right and left sides, respectively. Pinch strength measured 1.5 kg on the left side and 2.0 kg on the right. Before surgery, the patient was incapable of grasping; after surgery, a useful grasp had been restored bilaterally., (Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To report the clinical outcomes and complications for a cohort of patients who had extra-articular distal radius malunions treated with isolated ulnar-shortening osteotomy (USO). A second purpose was to define the dorsal angulation limit that would still result in clinical and functional improvement after isolated USO for distal radius malunion. We postulated that patients with up to 20° dorsal or volar tilt could be successfully treated with isolated USO., Methods: We conducted a retrospective chart review for all patients who had an isolated USO for the treatment of ulnar impaction syndrome after distal radius malunion between January 1990 and December 2011. A total of 18 patients underwent isolated USO after distal radius malunion. The mean age of the patients was 53 years and the mean duration of follow-up was 34 months. We used Wilcoxon signed-rank tests to compare preoperative and postoperative range of motion; pain; Quick Disabilities of the Arm, Shoulder, and Hand scores; and radiographic measurements., Results: Average intraoperative ulna shortening was 5.6 mm. Average flexion-extension arc improved from 79° preoperatively to 105° postoperatively. Average pronation-supination arc improved from 121° preoperatively to 162° postoperatively. Average visual analog scale pain score improved from 4.1 to 1.9. Average Quick Disabilities of the Arm, Shoulder, and Hand score improved from 43 to 11., Conclusions: This case series demonstrated a significant improvement in pain score and range of motion after isolated USO for distal radius malunion. Patients with up to 20° dorsal tilt and radial inclination as low as 2° demonstrated improved clinical and functional outcomes after isolated USO. Given the comparable functional outcomes with shorter operative times and lower complication rate requiring fewer secondary surgeries, isolated USO is an attractive alternative to distal radius osteotomy for the management of distal radius malunion in patients with up to 20° dorsal tilt., Type of Study/level of Evidence: Therapeutic IV., (Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess the clinical outcome and accuracy of prebent plate fixation in corrective osteotomy for malunited upper extremity fractures using a plastic bone model manufactured by preoperative computer simulation., Methods: Nine consecutive patients underwent computed tomography (CT)-based 3-dimensional corrective osteotomy for malunited upper extremity fractures. There were 4 cubitus varus deformities, 1 cubitus valgus deformity, and 4 forearm diaphyseal malunions. We constructed a computer model of the affected bones using the CT data and simulated the 3-dimensional deformity correction on a computer. A real-sized plastic model of the corrected bone was manufactured by rapid prototyping. We used a metal plate, prebent to fit the plastic bone model, in the actual surgery. Patients were evaluated after an average follow-up of 22 months (range, 14-36 mo). We retrospectively collected radiographic and clinical data at the most recent follow-up and compared them with preoperative data. We also performed CT after surgery and evaluated the error in corrective osteotomy as the difference between preoperative simulation and postoperative bone model., Results: The range of forearm rotation and grip strength in patients with forearm malunions improved after corrective osteotomies of the radius and ulna. Wrist pain, which 2 patients with forearm malunion had experienced before surgery, disappeared or decreased substantially after surgery. Radiographic examination indicated that preoperative angular deformities were nearly nonexistent after all corrective osteotomies. Three-dimensional errors in the corrective osteotomy using a prebent plate, as evaluated by CT data, were less than 3 mm and 2°., Conclusions: Prebent plate fixation in corrective osteotomy for malunited upper extremity fractures using a 3-dimensionally corrected, real-sized plastic bone model prepared by preoperative computer simulation is a precise and relatively easily performed technique that results in satisfactory clinical outcome., Type of Study/level of Evidence: Therapeutic IV., (Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: Patient-rated instruments are increasingly used to measure orthopedic outcomes. However, the clinical relevance of modest score changes on such instruments is often unclear. This study was designed to define the minimal clinically important differences (MCIDs) of the Disabilities of the Arm, Shoulder, and Hand (DASH), QuickDASH (subset of DASH), and Patient-Rated Wrist Evaluation (PRWE) questionnaires for atraumatic conditions of the hand, wrist, and forearm., Methods: We prospectively analyzed 102 patients undergoing nonoperative treatment for isolated tendinitis, arthritis, or nerve compression syndromes from the forearm to the hand. By phone, patients completed the DASH, QuickDASH, and PRWE at enrollment and at 2 weeks (n = 78 used in the analysis) and 4 weeks (n = 24 used in the analysis) after initiating treatment. Patients reporting clinical improvement each contributed a single data point categorized as no change (n = 41), minimal improvement (n = 30), or marked improvement (n = 31) via a validated anchor-based approach. We calculated the MCID as the mean change score for each outcome measure in the minimal improvement group., Results: The MCID (95% confidence interval) for the DASH was 10 (5-15). The MCID for the QuickDASH was 14 (9-20). The MCID was 14 (8-20) for the PRWE. The MCID values were significantly different from changes in these outcome measures at times of either no change or marked improvement. The MCID values positively correlated with baseline outcome measure scores to a greater degree than final outcome measure scores., Conclusions: Longitudinal changes on the DASH of 10 points, on the QuickDASH of 14 points, and on the PRWE of 14 points represent minimal clinically important changes. We recommend application of these MCID values for group-level analysis when conducting research and interpreting data examining groups of patients as opposed to assessing individual patients. These MCID values may provide a basis for sample size calculations for future investigation using these common patient-rated outcome measures., Type of Study/level of Evidence: Diagnostic III., (Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To assess long-term functional outcome after ulnar head excision for distal radioulnar joint dysfunction with prior or concomitant wrist trauma. We hypothesized that long-term outcomes would reflect good functional results with satisfactory pain relief., Methods: A retrospective chart review identified patients who had undergone the Darrach procedure for traumatic or posttraumatic distal radioulnar joint (DRUJ) pathology. We assessed subjective outcomes using a visual analog scale questionnaire to assess pain, wrist stability, and overall satisfaction. We evaluated objective functional outcomes using the Quick Disabilities of the Shoulder, Arm, and Hand and Patient-Rated Wrist Evaluation measures. Final radiographs were compared with preoperative x-rays to investigate the effect of possible ulnar impingement syndrome (convergent instability)., Results: A total of 98 patients with 99 wrists met our predetermined inclusion criteria. Of these, 27 patients with a total of 27 wrists were available for final follow-up, 15 of whom were available for final in-office follow-up with radiographs (6-20 y). Patients displayed an average Quick Disabilities of the Shoulder, Arm, and Hand score of 17 and a Patient-Rated Wrist Evaluation score of 14. Final average visual analog scale scores for pain (0-4), pain with activity (0-4), overall satisfaction (0-4), and wrist stability (0-10) were 0.1, 0.6, 3.7, and 1.5, respectively. Final average wrist range of motion was 85°/78° and 41°/45° for pronation-supination and flexion-extension, respectively. A total of 7 patients displayed radioulnar impingement based on dynamic radiography. This ulnar impingement was not associated with clinical reports of pain and did not affect outcome measures in a statistically significant manner., Conclusions: The Darrach procedure provides reliably good long-term subjective and objective results for the treatment of a symptomatic DRUJ after a distal radius fracture. Patients can expect to have excellent forearm range of motion at long-term follow-up. Nearly one-half of patients had dynamic convergence of the DRUJ when stressed radiographically; however, the presence of radiographic dynamic convergence did not influence clinical outcomes., (Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: To investigate the dynamic stabilizing effect of the extensor carpi ulnaris (ECU) on the distal radioulnar joint (DRUJ) and the ulnocarpal joint in a simulated model of triangular fibrocartilage complex (TFCC) injury., Methods: Using 8 fresh-frozen cadavers, we fixed the humerus and ulna at 90° of elbow flexion, and the radius and hand were allowed to rotate freely around the ulna. Passive mobility was tested by translating the radiocarpal unit relative to the ulna along dorsal-palmar directions. Unit displacement was measured by an electromagnetic tracking device in different forearm rotations and under varied loading to the wrist motor tendons. Magnitudes of displacement were compared between different loading patterns of the prime wrist movers in the TFCC-sectioned wrists. The effect of sectioning the ECU subsheath was analyzed., Results: When physiological loads were applied to all of the prime wrist movers, the magnitude of displacement during passive mobility testing decreased in supination and neutral rotation. After ECU tendon loading was released, mobility increased again in supination and neutral rotation. When the load was applied only to the ECU tendon, mobility decreased in supination and neutral rotation as compared with unloaded. Little change in the mobility was found in pronation regardless of the tendon loading pattern. After sectioning of the ECU subsheath, the stabilizing effect of the ECU decreased in neutral rotation., Conclusions: In a neutral wrist position with complete sectioning of the TFCC, the ECU dynamically stabilized the DRUJ and the ulnocarpal joint in supination and neutral forearm rotation. The ECU subsheath assisted ECU tendon stabilization on the ulnar side of the wrist, especially in the neutral rotation., Clinical Relevance: Maintaining the ECU and its subsheath may reduce DRUJ instability in patients with TFCC injuries., (Copyright © 2012 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: This study proposed a method of restoring the longitudinal stability of the forearm provided by the central band of the interosseous membrane (IOM) by using a percutaneously placed suture button construct. We hypothesized that supporting the forearm IOM with a suture button construct would restore longitudinal stability in a cadaveric model of the Essex-Lopresti lesion., Methods: We assessed 7 adult cadaver upper extremities radiographically for evidence of previous elbow, forearm, or wrist fracture. Each limb was mounted onto a materials testing system with the elbow held at 90° and the forearm in neutral. The intact specimen was loaded cyclically at 134 N to determine the native mobility of the forearm segment. Each specimen was tested after each of the following steps: radial head removal, transection of the IOM, and suture button construct reconstruction of the IOM. After the final reconstruction, each specimen was examined for forearm range of motion and evidence of neurovascular injury., Results: Removal of the radial head and sectioning of the IOM sequentially increased average proximal migration of the radius by 3.6 and 7.1 mm, respectively. After reconstruction with the suture button construct, the IOM was restored to the intact state with only the radial head removed. Forearm rotation was not compromised by the reconstruction, and there was no evidence of neurovascular injury in any specimen., Conclusions: A percutaneously placed suture button construct can restore the longitudinal stability provided by an IOM. The method described did not limit forearm rotation. We encountered no neurovascular injury in the specimens tested in this series. This construct may be an effective adjunct when combined with bony reconstruction to treat longitudinal forearm axis injuries., (Copyright © 2010 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Purpose: Many patients develop distal radioulnar joint (DRUJ) pain and loss of forearm rotation after distal radial fractures. Residual distal radial deformity is one potential cause of DRUJ dysfunction; however, the parameters of distal radial fracture alignment that lead to an acceptable functional outcome are poorly defined in the literature., Methods: We used 8 fresh-frozen cadaveric specimens in this in vitro study to examine the effect of simulated distal radius fracture misalignment on forearm rotation. A distal radial osteotomy was performed just proximal to the DRUJ and a custom-made, 3-degrees-of-freedom modular implant designed to simulate distal radius fracture deformities was secured in place. This allowed for accurate simulation of dorsal angulation, dorsal translation, and radial shortening, both independently and in combination. We examined the effects of distal radius deformity in the setting of both an intact and sectioned triangular fibrocartilage complex., Results: Pronation was not significantly affected until dorsal angulation reached 30 degrees . Dorsal translation of up to 10 mm or radial shortening up to 5 mm had no effect on forearm rotation. Combined deformities had a greater effect on forearm motion than isolated malpositions. Dorsal angulation of > or =20 degrees combined with 10 mm of dorsal translation or 20 degrees of angulation with 2.5 mm of radial shortening resulted in a significant decrease in forearm pronation. There was no effect of distal radial deformities, either isolated or combined, on the magnitude of forearm rotation after sectioning the triangular fibrocartilage complex., Conclusions: This study demonstrates that a broad range of distal radius fracture malpositions can be tolerated before a notable loss in forearm range of motion is evident. Combined deformities are more likely to result in a clinically important loss of forearm rotation, and this should be considered when choosing the optimal management of patients with displaced distal radial fractures. Disruption of the triangular fibrocartilage releases the tether on the DRUJ, allowing for preservation of forearm motion even in the setting of marked osseous deformities.

Purpose: The purpose of this study was to evaluate the biomechanical effect of core decompression of the distal radius for the treatment of Kienböck's disease., Methods: In 7 fresh cadaver upper extremities, axial loads were applied and the pressure in the radiocarpal joint measured using pressure-sensitive film before and after core decompression of the distal radius., Results: Biomechanically, the stiffness of the distal forearm statistically decreased significantly from 229.4 N/mm to 198.6 N/mm after core decompression. No or minimal changes in the distribution of the force in each radiocarpal fossa and ulnocarpal fossa, the area of contact in each fossa, and the location of the centroid of force were observed., Conclusions: Core decompression of the distal radius in the setting of Kienböck's disease has been documented good clinical outcomes, yet the biomechanical analysis of this surgical technique does not demonstrate obvious unloading of the lunate.

Purpose: The purpose of this study is to determine whether release of the distal volar forearm fascia (DVFF) is necessary at the time of median nerve decompression for carpal tunnel syndrome., Methods: Five fresh-frozen cadaver specimens were mounted vertically with the hand dependent and a 2.27-kg weight suspended from the fingers. A pressure sensor wire was used to measure pressures starting just distal to the transverse carpal ligament (TCL). The wire was withdrawn proximally in 5-mm increments and into the forearm until pressure was below 10 mm Hg. An incision in the forearm was extended distally until the pressure sensor was found. The distance from this point to the distal volar wrist crease was measured. The TCL was released, keeping the DVFF intact, and the experiment was repeated. Paired t-tests determined whether there were statistically significant differences between measurements before and after TCL release., Results: Average peak pressure under the intact TCL was 57.8 +/- 10.1 mm Hg. Average peak pressure under the DVFF with the TCL intact was 61.2 +/- 43.6 mm Hg. Following release of the TCL, average peak pressure beneath the TCL significantly decreased to 14.0 +/- 9.0 mm Hg, whereas average peak pressure at the intact DVFF increased to 64.8 +/- 48.7 mm Hg. Average locations where DVFF pressure became less than 10 mm Hg with an intact TCL and with released TCL were 4.30 +/- 1.8 cm and 4.00 +/- 1.8 cm proximal to the distal volar wrist crease, respectively. There was no significant difference between DVFF pressures before or after TCL release., Conclusions: In a cadaver model of carpal tunnel syndrome, release of the TCL alone is associated with persistent pressures >30 mm Hg in the region of the DVFF. Release of the TCL did not significantly change the location of the pressure drop-off under the DVFF.

Purpose: To determine the relationship between the length of the ulna as a proportion of height (proportional ulnar length [PUL]), forearm and wrist ranges of motion, and degree of observable deformity in people with hereditary multiple exostoses., Methods: One hundred forty-two people with hereditary multiple exostoses were examined; 35 were under the age of 15 years and therefore were presumed to be skeletally immature. Elbow, forearm, and wrist motion were measured, and the radius and ulna were palpated for osteochondromas. Ulnar length was estimated as a proportion of height (PUL) in skeletally immature subjects. The relationships between total active motion, number of palpable osteochondromas, and proportional length were examined for one randomly selected limb from each subject., Results: A negative correlation was found between the number of palpable osteochondromas and range of forearm rotation. The degree of forearm motion in those under the age of 15 years was directly related to PUL and indirectly related to the number of palpable osteochondromas. Children whose PUL is within the normal range have a normal range of motion., Conclusions: In a child with hereditary multiple exostoses affecting the forearm, the PUL is associated with the range of movement and deformity, and it can be a useful adjunct in deciding the appropriate management.

Purpose: To quantify the magnitude of rotational correction possible when comparing a single forearm bone osteotomy and fixation with stepwise osteotomy and fixation of both bones in a cadaver model and to determine if the order in which the stepwise osteotomies are performed influences the amount of correction., Methods: Ten fresh-frozen cadaveric forearms were fixed to a frame positioned in the field of view of a motion-capture system. An experimental supination contracture was induced in full supination. Cadaver forearms were assigned randomly to group I (ulna osteotomy, rotation, plating) or group II (radius osteotomy, rotation, plating). Cadavers in group I were used later in group III (ulna + radius) by completing a radial osteotomy, rotation, and fixation in the forearms with the plated ulna. Similarly the specimens assigned to group II were used later in group IV (radius + ulna) by completing an ulna osteotomy, rotation, and fixation in the forearms with the plated radiuses. Measurements of forearm pronation were made after single-bone (groups I, II) and stepwise both-bone (groups III, IV) rotational osteotomies., Results: Stepwise rotational osteotomy and fixation of the ulna followed by the radius produced significantly more corrective pronation (101 degrees) than rotating the radius followed by the ulna (65 degrees). Rotating the radius gave only moderate correction (58 degrees) and minimal correction was produced by ulna osteotomy alone (15 degrees)., Conclusions: Rotational osteotomy of both forearm bones can create approximately 100 degrees of correction when performed at the proximal ulna followed by the distal radius. If less rotation is needed then the distal radius osteotomy alone can provide approximately 60 degrees of correction.

Purpose: The forearm in children with cerebral palsy often assumes uncontrolled dynamic positioning in pronation when the hand is put into use. This hypertonic positioning seems to be an expression of dystonia rather than spasticity. This article reports the effect of pronator teres rerouting (PTR) using the technique of tendon Z-lengthening and repair on active motion and on forearm positioning during use., Methods: Thirty-one patients who had pronator teres rerouting were observed before and after surgery for active and passive forearm range of motion, changes in dynamic forearm positioning, and the performance of 5 functional tasks related to forearm rotation. The primary indication for surgery was pronation positioning of 25 degrees or greater because that positioning precludes grasping a glass or cup of water., Results: The follow-up period averaged 39 months. The average active supination increased 65 degrees, and the average dynamic positioning changed from 26 degrees pronation to 7 degrees pronation. Thirty of the 31 patients gained the ability to hold a cup of water in the involved hand. Nine children positioned the hand in supination during grasp., Conclusions: Pronator teres rerouting improves both active supination and dynamic forearm positioning in children with cerebral palsy. The use of the technique described in the literature resulted in slight overcorrection of forearm positioning in the nine children. This finding is consistent with the concept that positioning disorders are at least partly dystonic rather than spastic. It is recommended that the transfer be tensioned more loosely in children who have excessive dynamic hypertonia., Type of Study/level of Evidence: Therapeutic, Level IV.

Purpose: To present the authors' experience with internal fixation of the radius and ulna as a surgical option for correction of supination contracture of the forearm., Methods: Twelve patients (13 limbs) had an osteotomy of the radius and ulna for a supination deformity secondary to a residual brachial plexus or spinal cord injury. Surgery consisted of proximal ulna and distal radius osteotomies combined with plate fixation., Results: The average age of the patients at the time of surgery was 11 years. Five limbs had fixed supination deformities and 8 limbs lacked pronation beyond neutral. The average preoperative supination deformity (either fixed or measured at midarc) was 76 degrees. The average intraoperative correction was 86 degrees. The average follow-up period was 16 months. The average midrange resting position maintained at final follow-up evaluation was 2 degrees of pronation. All limbs ultimately obtained radiographic and clinical union of the osteotomy sites. Complications included 6 plate fractures; however, only 1 patient required revision internal fixation., Conclusions: The combination of a proximal ulna and distal radius osteotomy with internal fixation can provide excellent correction, but the implant must be strong enough to hold the osteotomies rigidly in the corrected position during the time needed for union., Type of Study/level of Evidence: Therapeutic, Level IV.

Purpose: To analyze the influence of subluxation of the distal radioulnar joint (DRUJ) on restricted forearm rotation after distal radius fracture., Methods: Twenty-two cases of healed unilateral distal radial fracture with restricted forearm rotation were included in the study. The subluxation of the DRUJ was evaluated using helical computed tomography scan at neutral, maximum pronation, and maximum supination and presented as the percent displacement of the ulnar head in both the injured and uninjured sides. The radiographic parameters of palmar tilt, radial inclination, dorsal shift, radial shift, and ulnar variance were measured on plain x-ray films and the rotational deformity of the distal radius was evaluated from the computed tomography scan. The differences of each radiographic parameter from the uninjured side were calculated. The relationships between the restricted forearm rotation and the percent displacement of the ulnar head and each of the radiographic parameters were analyzed statistically., Results: When forearm pronation was restricted the ulnar head was located palmarly at neutral, maximum supination, and maximum pronation with severe dorsal tilt of the distal radius. When supination was restricted the ulnar head was located dorsally at maximum supination with severe ulnar-positive variance., Conclusions: The subluxation of the DRUJ was related to restricted forearm rotation. The radiographic parameters of palmar tilt and ulnar variance showed an adverse influence on the position of the ulnar head at the DRUJ, which might lead to restricted forearm rotation after distal radial fracture.

Purpose: Longitudinal radioulnar dissociation may result when compressive load to the hand causes excessive proximal migration of the radius with interosseous ligament (IOL) disruption and radial head fracture. Although radial head salvage or arthroplasty and temporary distal radioulnar joint pinning constitute the current treatment for this injury IOL reconstruction has been proposed to restore normal forearm mechanics. To help provide a biomechanical basis for IOL reconstruction we measured load transfer and proximal migration of the radius with the IOL intact, cut, and reconstructed while leaving the radial head intact., Methods: We dissected the central third of 12 normal cadaveric forearms to bone-IOL-bone. We applied 136 N of compressive load to the hand and measured proximal radial migration and 3-dimensional force vectors acting in the distal radius, distal ulna, IOL, proximal radius, and proximal ulna. Experiments were performed in neutral forearm rotation and neutral elbow varus-valgus. The protocol was repeated with the IOL intact, cut, and reconstructed with single and double flexor carpi radialis allografts., Results: With the IOL intact 94% +/- 3 % of hand load was in the distal radius with 75% +/- 2% was transmitted to the proximal radius. With the IOL cut 92% +/- 2% of hand load was in the distal radius and this was unchanged at the proximal radius. With single flexor carpi radialis reconstruction 94% +/- 3% of hand load was in the distal radius and 80% +/- 2% was in the proximal radius; with double flexor carpi radialis reconstruction these numbers changed to 95% +/- 3% and 74% +/- 2%, respectively. Forces in the forearm were mainly in the longitudinal and transverse directions with negligible components in the dorsal-volar direction. Transverse force in the IOL was about half that of the longitudinal force in the intact and reconstructed states., Conclusions: When the IOL is cut and load is applied to the hand the unloading of the proximal radius and the transversely directed force that compresses normally across the proximal and distalradioulnar joints is lost. Reconstruction of the IOL can restore the normal load transfer characteristics. These data help provide a biomechanical basis for IOL reconstruction. Further research on the biomechanics of IOL reconstruction in the setting of radial head replacement along with clinical evaluation is needed.

Purpose: Longitudinal radioulnar dissociation occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head (Essex-Lopresti injury). Proximal migration of the radius results in a wrist with a positive ulnar variance, which leads ultimately to painful ulnar-sided wrist degeneration and wrist pain during grasping activities that involve axial loading or ulnar deviation of the wrist. In theory reconstruction of the IOM with a graft substitute can limit proximal migration of the radius, thereby preserving wrist function. The objective of this study was to measure the abilities of 3 graft tissues to limit proximal radial displacement compared with the native IOM in a radial head-deficient cadaver model., Methods: Sixteen fresh-frozen cadaveric forearms were loaded axially to 134 N through the potted central 3 metacarpals; the elbow was flexed to 90 degrees with the wrist in neutral rotation. Proximal displacement of the radius relative to the capitellum was measured. With the radial head excised specimens were first tested with the IOM intact. The IOM was then sectioned and central band IOM reconstructions were performed on each specimen using the following tissues: palmaris longus tendon, flexor carpi radialis (FCR) tendon, and a 1-cm- wide bone-patellar tendon-bone (BPTB) onlay allograft. Ten loading cycles were performed with each test configuration. Proximal radial displacement between 13.4 N and 134 N of applied wrist force was analyzed for the 10th loading cycle. The increase in proximal displacement between the first and 10th loading cycles (recorded at 134 N of wrist force) represented permanent elongation of the graft., Results: Mean cross-sectional areas were 5.11 mm2 for the palmaris longus tendon, 15.23 mm2 for the FCR tendon, and 51.59 mm2 for the BPTB allograft. Mean proximal radial displacements were 3.04 mm (intact IOM), 4.37 mm (BPTB), 4.92 mm (FCR tendon), and 6.43 mm (palmaris tendon); all means were significantly different from each other. Mean permanent graft elongations were 0.06 mm (IOM), 0.36 mm (BPTB), 1.25 mm (FCR tendon), and 1.80 mm (palmaris tendon); all means were significantly different from each other with the exception of means for palmaris longus vs FCR and BPTB vs IOM., Conclusions: No graft reconstruction limited proximal radial displacement as effectively as the native IOM. Of the 3 graft tissues tested the BPTB allograft had the greatest cross-sectional area, allowed the least proximal radial displacement, and displayed the least permanent elongation after 10 cycles of loading. The relatively thin and narrow palmaris longus tendon appears to be the least desirable choice for IOM reconstruction because of its relatively low stiffness and tendency to elongate permanently after cyclic loading. When the radial head is absent rupture of the IOM allows unopposed proximal displacement of the radius relative to the ulna as the wrist is loaded axially. In the present tests all 3 graft tissues used to reconstruct the IOM limited proximal radial displacement. The choice of graft material is an important variable if IOM reconstruction is considered for treatment of an Essex-Lopresti injury.

Purpose: Longitudinal radioulnar dissociation (Essex-Lopresti injury) occurs when traumatic axial loading through the wrist disrupts the interosseous membrane (IOM) of the forearm and fractures the radial head. Proximal migration of the radius results in an ulnar-positive wrist, which can lead to painful ulnar-sided wrist degeneration and distal radioulnar joint instability. The purpose of this study was to measure the ability of an IOM reconstruction used in combination with a metal prosthetic radial head implant to reduce distal ulnar forces in a cadaveric model. The effects of varying the initial graft pretension on distal ulnar force were also studied., Methods: Twelve fresh frozen and thawed cadaveric forearms had a miniature load cell installed to record force in the distal ulna as the wrist was loaded axially to 134 N of compression force in neutral rotation. Intact forearms were tested first with the elbow in valgus and varus alignments. Loading tests were repeated after (1) insertion of a metal radial head implant that restored radius anatomic length, (2) excision of the IOM (with a radial head implant), and (3) reconstruction of the IOM using a palmaris longus tendon autograft (with a radial head implant). The implant then was removed and loading tests were repeated using 3 levels of initial graft pretension., Results: Mean distal ulnar forces with an intact forearm were 23% of applied wrist force in the varus alignment and 12% in the valgus alignment. Mean force levels after insertion of the implant were 18% (varus) and 13% (valgus); these were not significantly different from corresponding values for the intact forearm. Mean force levels after section of the IOM were 30% (varus) and 14% (valgus); these were not significantly different from corresponding values for the intact forearm (varus and valgus) but the mean for varus was significantly greater than the corresponding value with an implant. After IOM reconstruction with a palmaris longus tendon tensioned to 22 N mean distal ulnar forces were 8% (varus) and 7% (valgus); these means were significantly less than the corresponding values for all prior test conditions. With the radial head removed increasing the level of graft pretension reduced significantly mean distal ulnar force., Conclusions: With the IOM resected insertion of a metal radial head implant alone did not reduce distal ulnar forces to intact forearm levels. When an IOM reconstruction was performed in combination with the implant mean distal ulnar force was reduced significantly to a level below that for the intact forearm. Applying pretension to the graft displaced the radius distally thereby making the wrist more ulnar negative and reducing distal ulnar force. Our results suggest that an IOM reconstruction used in combination with a metal radial head implant theoretically could help reduce distal ulnar impaction in an Essex-Lopresti injury.

Purpose: To evaluate rotational deformity in malunited fractures of the distal radius and its effect on forearm rotation., Methods: Thirty-seven patients with a symptomatic malunion of the distal radius (25 with dorsal angulation and 12 with volar angulation) were assessed for rotational deformity of the distal fragment. Spiral computed tomographic scans were taken of both wrists. Rotational deformity was evaluated by comparing the radial torsion angle of the injured and uninjured sides according to Frahm. Multivariable regression analyses were used to identify the radiologic parameter that had the most important influence on forearm rotation., Results: Of the 37 patients, 23 showed a rotational deformity of the distal radius. In both dorsally and volarly angulated malunions, pronation and supination deformities were identified. There was a tendency toward more pronation deformities with volar malunion. Volar angulated malunion with a rotational deformity of less than 10 degrees showed the smallest amount of forearm supination. Losses of pronation-supination did not correlate with the amount of rotational deformity., Conclusions: This study showed that rotational deformity is common with angulated malunions of the distal radius. The effect on forearm rotation should not be overestimated. Pretreatment computed tomographic scanning of both wrists to identify and measure malrotation of the distal radius may be helpful to improve the outcome after corrective osteotomy.

Purpose: In this study we used a tendon transfer technique (consisting of rerouting of the brachioradialis with interosseous membrane release) to restore active forearm pronation in patients with supination deformity secondary to brachial plexus birth palsy., Methods: Four children (3 with flexible supination deformities, 1 with a fixed supination deformity) whose ages ranged between 5 and 9 years had brachioradialis rerouting with interosseous membrane release., Results: Mean active forearm rotation was improved from 28 degrees supination before surgery to 49 degrees pronation after surgery. No patient developed elbow contracture during a minimum of 12 months of follow-up evaluation (40 months in 2 patients, 14 months in 1 patient, 12 months in 1 patient)., Conclusions: These results suggest that brachioradialis rerouting combined with interosseous membrane release may be a successful means to correct supination deformity of the forearm.

Purpose: To quantify and compare the disabilities caused by reduced and absent wrist motion using objective measurements of task performance and perceived disability, and to assess the compensatory motions of the shoulder, elbow, forearm, and trunk caused by impaired wrist motion., Methods: A clinical study of 21 normal subjects was done to measure physical performance and to assess wrist function under conditions of reduced (30 degrees flexion and 30 degrees extension) and nearly absent wrist motion using established physical tests and questionnaires (Disabilities of the Arm, Shoulder, and Hand [DASH], Patient Rated Wrist Evaluation [PRWE], and a study-specific survey). The clinical study also measured compensatory motions of the shoulder, elbow, forearm, and trunk., Results: Average times to perform the Jebsen test and activities of daily living (ADLs) test increased for both motion-restricted conditions of the wrist but did not differ significantly between the conditions. Questionnaire scores regarding function were significantly worse for both motion-restricted conditions and poorest for nearly absent motion. Average compensatory motions in the extremity and trunk statistically increased for both motion-restricted conditions but were not marked and did not differ between the conditions. High variability among subjects occurred in all physical tests and questionnaires for both motion-restricted conditions., Conclusions: Perceived disability from reduced wrist motion appeared greater than measured functional loss using common physical tests and outcome surveys.

Purpose: This study was designed to provide quantitative information concerning the functions of the ligaments that stabilize the distal radioulnar joint (DRUJ). This joint permits the radius to rotate around a nearly fixed ulna allowing supination and pronation of the hand. Understanding their function is important in developing procedures for reconstruction., Methods: Using a ligament tension transducer that hooked under the center of the ligament and deflected it laterally while measuring the force required, we determined the tensions in 6 ligaments in 9 cadaver arms in pronation and supination of the hand. These ligaments included those of the DRUJ: palmar distal radioulnar ligament (PDRUL) and dorsal distal radioulnar ligament (DDRUL); and the ulnocarpal joint ligaments: ulnolunate ligament (ULL), ulnotriquetral ligament (UTL), and the ulnocarpal collateral ligament (UCCL), which includes the subsheath of the extensor carpi ulnaris, and the dorsal ulnocarpal ligament (DUCL)., Results: For the ligaments of the DRUJ in supination, the mean tension in the PDRUL (2.6 N) was greater than that of the DDRUL (0.8 N), whereas in pronation the mean tension in the PDRUL (1.1 N) was less than that of the DDRUL (1.7 N). For the ulnocarpal ligaments in supination, the ligament tensions in the ULL, UTL, and the UCCL were significantly greater than the same ligaments with the forearm pronated. The DUCL tension remained unchanged throughout supination and pronation., Conclusions: In supination of the forearm all ligaments except for the DDRUL had equivalent tensions, indicating their role in stabilizing the joint to this motion. In pronation ligament tensions generally were lower but were distributed over all 6 ligaments tested. DUCL tension was equivalent in both supination and pronation, unlike the other ligaments that had greater tensions in supination.

Purpose: Although the forearm support band has been hypothesized to reduce force and thus inflammation and degeneration at the extensor carpi radialis brevis (ECRB) origin, little evidence exists to support an actual effect. We present both a cadaveric and clinical model that show the effect and principles of the forearm support band., Method: The cadaver model measured forces at the ECRB origin as various pressures were applied to the forearm support band and while the ECRB tendon was loaded distally. For clinical correlation support band pressure during rest and activity was measured in healthy individuals., Results: Our results revealed an increased forearm support band effect with increased band pressure and a decreased relative effect with increased force applied distally. For clinical correlation the support band pressure during activity was measured in 21 healthy volunteers while controlling for the application pressure in 2 common support band designs. This resulted in activity pressures ranging from 43 to 192 mm Hg dependent on the starting pressure of application., Conclusions: Although further clinical evaluation is necessary to determine the most appropriate clinical indications and application pressures for the forearm support band these combined results suggest that the forearm support band may be most effective when applied to 30 to 50 mm Hg at rest, resulting in up to 120 mm Hg pressure during activity. According to our model this would result in a force reduction at the ECRB origin of approximately 13% to 15% throughout a range of activity levels.

Purpose: To study changes in the relationship of the distal radius and ulna after progressive resection of the distal ulna., Method: Six-degree-of-freedom motion sensors were used to determine relative motion and a displacement transducer was used to determine strain changes in the interosseous membrane (IOM). These were applied in cadaveric specimens loaded to simulate wrist motion and axial compressive forces., Results: Strain in the IOM decreased with increasing resection of the distal ulna. The distance between the radius and ulna decreased with increasing resection up to 20% of ulna length., Conclusions: The decreased strain in the IOM and stabilization of the distance between the radius and ulna at 20% resection level provides biomechanical support for the satisfactory clinical results seen after wide ulnar resection. Wide excision of the distal ulna may be a viable salvage alternative to creation of a one-bone forearm.

Purpose: The purpose of this study was to describe the results of a newly developed method of correction osteotomy for congenital radioulnar synostosis. With this method the osteotomy is performed at the distal one third of the radius and proximal one third of the ulna. After K-wires are inserted intramedullarly into both bones the forearm is derotated manually to the position planned before surgery followed by cast immobilization., Methods: Four patients with an average age of 3.9 years underwent surgery with this method and were followed-up for 45.8 months. All of their forearms were fixed before surgery at over 70 degrees of pronation., Results: The average correction after surgery was 65 degrees and bone union occurred at 8 weeks after surgery without any complications. The patients' ability to perform daily activities showed a marked improvement after surgery, but there was a 20 degrees loss of correction during cast immobilization in one case., Conclusion: This method is a simple and safe technique to derotate the forearms of the patients with congenital radioulnar synostosis that are fixed in pronation.

A kinematic analysis of a progressive, ulnar-sided wrist injury was performed using a cadaver model to study the static and dynamic stabilizers of the distal radioulnar joint with a 3-dimensional motion tracking system. Anatomically based loads were applied to achieve pronation and supination and then the specimens were evaluated after serial transection of the triangular fibrocartilage, the extensor carpi ulnaris sheath, and the ulnocarpal ligaments. Statistically significant increases in translation of the radius relative to the ulna occurred with sectioning of both the triangular fibrocartilage proper and the extensor carpi ulnaris tendon sheath. No significant change in position of the forearm could be appreciated with subsequent sectioning of the ulnocarpal ligaments. Our observations support the idea that the ulnocarpal ligaments do not need to be surgically reconstructed when there are serious injuries to the triangular fibrocartilage complex.

Pressure reduction for standard open fasciotomy and a novel endoscopic fascial release were compared in experimental conditions of elevated forearm compartment pressures by continuously monitoring intracompartmental pressures in 22 cadaver forearms. Both methods were effective in diminishing tissue pressures. Intracompartmental pressures were reduced to significantly lower levels following open versus endoscopic assisted fasciotomy (2.9 mm Hg vs. 13.2 mm Hg). In the endoscopic group a statistically significant second decrease in pressure was observed after dermatomy, reducing intracompartmental tissue pressures from 13.2 mm Hg to 3.1 mm Hg. The results of this study suggest that endoscopic assisted fasciotomy can reduce elevated tissue pressures, confirming previous findings that fascial release is of primary importance in decreasing intracompartmental tissue pressures. Open fasciotomy, however, gave significantly greater decompression than the endoscopic technique, a difference that may be even more substantial in the clinical setting due to several limiting factors of this in vitro model. Our results also suggest that immediate skin closure following fasciotomy increased tissue pressure and therefore should be avoided.

Posttraumatic limitation of forearm rotation can be the result of pathology at any location along the forearm axis. Scar contracture of the distal radioulnar joint (DRUJ) capsule, independent of the triangular fibrocartilage complex (TFCC), is one of the sources that may influence the pronosupination arc. We dissected the wrists of 8 fresh-frozen cadaver specimens to characterize the precise anatomy, relationships, and dynamic characteristics of the entire DRUJ capsule. Additionally, we performed surgical DRUJ capsulectomy in 9 patients with recalcitrant limited forearm pronosupination that was unattributable to dysfunction at any other anatomic forearm location. We conclude that (1) the DRUJ capsule is a defined entity, separate from the triangular fibrocartilage, that is highly specialized to accommodate the distal ulna in forearm rotation; (2) in patients who have restored osseous anatomy after trauma, but have failed to regain pronosupination after maximal rehabilitation, the DRUJ capsule can be identified as the source of the limitation; and (3) DRUJ capsulectomy can markedly improve the arc of forearm rotation in carefully selected patients.

Seven fresh cadaveric specimens were used to determine the loss of forearm rotation with varying distal radius fracture malalignment patterns. Uniplanar malunion patterns consisting of dorsal tilt, radioulnar translation, or radial shortening were simulated by creating an osteotomy at the distal end of the radius, orienting the distal fragment position using an external fixator, and maintaining the position with wedges and a T-plate. Rotation of the forearm was produced by fixing the elbow in a flexed position and applying a constant torque to the forearm using deadweights. Forearm rotation was measured with a protractor. Dorsal tilt to 30 degrees and radial translation to 10 mm led to no significant restriction in forearm pronation or supination ranges of motion. A 5-mm ulnar translation deformity resulted in a mean 23% loss of pronation range of motion. Radial shortening of 10 mm reduced forearm pronation by 47% and supination by 29%.

A retrospective study was performed to analyze the results of elbow synovectomy, radial head excision, and anterior capsular release in 12 elbows in 11 patients with radiographic stage III inflammatory arthritis. The follow-up period averaged 6.1 years. Average flexion arc improved from 93 degrees (range, 80 degrees-110 degrees) to 116 degrees (range, 65 degrees-140 degrees), with flexion contracture improving 13 degrees. Total arc of forearm rotation increased from 95 degrees to 145 degrees. Ewald scores improved from an average of 37 to 84 points. Pain was eliminated or improved in all cases; functional improvement was noted in all patients. Serial postoperative radiographs showed no significant disease progression over time. These results suggest that combined synovectomy, radial head excision, and anterior capsular release effectively relieves pain and improves function in stage III inflammatory arthritis of the elbow.

Five patients with disabling symptoms related to proximal translation (> 1 cm) of the radius following radial head excision (Essex-Lopresti lesion) were treated with implantation of a frozen-allograft radial head prosthesis. Following restoration of neutral ulnar variance at the wrist, a size-matched frozen radial head allograft was implanted and secured to the proximal radius with internal fixation. In three patients, this was a two-stage procedure; radial length was restored gradually using an ilizarov external fixation device and the allograft was placed later. Patients were evaluated clinically and radiographically at a mean follow-up time of 3 years (range, 1-7 years). All patients had relief of wrist and elbow pain and were satisfied with the outcome of the operation. Forearm rotation improved by a mean of 37 degrees and wrist motion improved by a mean of 45 degrees. Forearm reconstruction with frozen radial head allograft implantation may be a beneficial method of treatment for this difficult problem.

A biomechanical cadaver study was performed to evaluate the effect of dorsally angulated distal radius fractures on the distal radioulnar joint. Frykman I distal radius fractures were simulated, and laxity measurements were taken with and without sectioning the triangular fibrocartilage complex and the interosseous membrane. The findings of this study were threefold. First, measured in terms of radial diastasis, incongruency of the distal radioulnar joint occurred with increasing dorsal tilt of the distal radius. It became most dramatic with a change of more than 20 degrees of dorsal angulation of the distal radius. This corresponds to approximately 10 degrees of dorsal tilt of the articular surface of the distal radius, as measured on an x-ray film. Second, increased dorsal angulation caused interosseous membrane tightness and limited maximum pronation and maximum supination. Third, distal radioulnar joint dislocation did not occur until both the triangular fibrocartilage complex and interosseous membrane were sectioned. These results reveal the importance of anatomic reduction of the distal radius fracture and evaluation of damaged soft tissue structures.

Numerous reconstructive procedures have been described for the treatment of chronic instability of the distal radioulnar joint or instability of the stump of the resected distal ulna. This biomechanical study presents an evaluation of the three basic design types that have been used in reconstruction. The initial static stability provided by the reconstructions was tested and compared with the stability of the intact joint. Our findings show that all reconstructive procedures failed to restore natural joint stability. A radioulnar sling design was the most effective of the three types, whereas tenodesis procedures and ulnar collateral ligament reconstruction were much less effective in providing stability. We conclude that current designs have significant biomechanical shortcomings. On the basis of our observations during testing, we believe that improved designs will require an intra-articular reconstruction that more closely duplicates the biomechanical functions of the triangular fibrocartilage complex.

To evaluate the effect of silicone replacement of the distal ulnar, hemiresection arthroplasty and the Darrach procedure on ulnar support of the carpus, changes in force transmission to the radius and ulnar were measured using load cells in axially loaded cadaver arms. Testing of the intact specimens in neutral position showed that an average of 17% of the axial load was borne by the ulna whereas the load decreased to 3.6% after silicone arthroplasty, to 2.4% after hemiresection arthroplasty, and to 1.0% after the Darrach procedure. Only by placing the silicone cap on the ulna to lengthen it by 4 mm did the ulna load become within 75% of that in the intact specimen. In the intact specimen, ulna loading increased with wrist extension and ulna deviation and decreased with flexion and radial deviation, while after the surgical procedures there was no significant change in ulna loading with wrist position.

Forty-one patients with cerebral palsy and pronation contracture of the forearm were treated with pronator teres rerouting compared with 16 patients who were treated with pronator teres tenotomy. The mean age of patients with pronator tenotomy was 4 years 3 months compared with 7 years 3 months for patients with rerouting. Follow-up averaged 94 months for tenotomy and 21 months for rerouting. Average gain in supination was 78 degrees for rerouting and 54 degrees for tenotomy. No patient lost active range of motion during follow-up. Although pronator teres tenotomy increased active supination of the forearm, greater active supination of the forearm was afforded patients treated with pronator teres rerouting.

Twenty-six patients with soft tissue sarcomas of the forearm and hand were treated with limb salvage protocols involving surgical wide excision, chemotherapy, and radiation therapy. Six received immediate or delayed reconstructive surgery to improve function. The average delay from the time of the first medical consultation until the correct diagnosis was made was 4.5 months. The average follow-up period was 44 months; a 91% survival rate was observed, with an 8% rate of local recurrence. Functional abilities were assessed by a questionnaire concerning work, household activities, and overall satisfaction with the surgical result. Eight-six percent of the patients had an excellent functional result, and 84% reported excellent satisfaction with their operation.

In deciding on suitable tendon transfers to replace denervated muscle-tendon units, important considerations are the strength and effectiveness of possible substitutes. A method is presented by which the strength of the wrist extensor muscles and their moment arms can be determined. The method can be applied to other muscles at other joints. It involves the use of a force transducer which measures the combined forces of the three wrist extensors in an isometric contraction. This moment for wrist extension, measured in the living intact arm, is the same as the sum of the moments of the three wrist extensor muscles. The contribution of each muscle to the total moment is calculated from ratios that have been developed from a quantitative study of moment arms and muscle masses in sixteen cadaver limbs. It is suggested that the ratio of one moment arm to another is fairly constant from subject to subject, and that muscle masses also have sufficiently similar ratios to each other to serve as the basis for practical estimations by the surgeon. Thus the surgeon needs only one or two direct measurements of moments externally and only one or two skeletal measurements on any living subject to be able to estimate the effectiveness of a number of muscles on the basis of cadaver studies such as this, and to project the behavior of a muscle after it has been transferred to a position where it will have new moment arms.