Bridge Plating is an Effective Adjunct Treatment for Complex Elbow Instability.

BACKGROUND: Managing persistent elbow instability and chronic dislocations presents challenges despite traditional treatments. Supplementary methods like immobilization and various fixations, though common, can carry high complication rates. This study assesses the efficacy of bridge plating in treating complex elbow instability through a retrospective review of patients. Data on characteristics, treatment duration, range of motion, complications, and evaluation scores were analyzed, providing insights into outcomes complications associated with bridge plating. RESULTS: Eleven patients were reviewed at an average follow-up of 80 ± 68 weeks. postoperatively. The average age was 53±14 years and there were 5 females and 6 males. The average BMI was 38. Bridge plating was used for a spectrum of complex elbow injuries. The average time from injury to bridge plating in acute cases was 29±19 days and 344±381 days in chronic cases. The average duration of bridge plating was 121 ± 72 days. At the time of plate removal, mean intraoperative elbow motion was extension 58±12°, flexion 107±14°, supination 66±23° and pronation 60±26°. At the latest follow-up visit, average elbow motion was extension 37±22°, Flexion 127± 17°, supination 72±15° and pronation 63±18°. There were 6 complications (55%); heterotopic ossification, ulnar neuropathy, wound failure over the plate in a thin patient, an ulnar shaft peri-prosthetic fracture due to a seizure induced fall, and elbow subluxation despite bridge plate fixation. One patient sustained a fracture of a 3.5mm locking bridge plate. One patient required a contracture release for persistent stiffness. Four of these complications can be directly attributed to the use of the bridge plate (36%). At final follow-up, the average patient rated elbow evaluation score was 34, with 0 indicating no pain and disability. The average single assessment numeric evaluation score was 66% for the 8 patients who had this available, with 100% being the best possible attainable score. CONCLUSION: Bridge plating effectively maintains joint reduction in selected complex elbow instability cases. However, patients with bridge plates often require a second surgery for removal and experience high rates of general complications due to the complexity of their condition.

Indomethacin for heterotopic ossification prophylaxis following surgical treatment of elbow trauma: a randomized controlled trial.

BACKGROUND: Heterotopic ossification is a frequent complication following surgical treatment of elbow trauma. The use of indomethacin to prevent heterotopic ossification is reported in the literature; however, its effectiveness is controversial. The purpose of this randomized, double-blind, placebo-controlled study was to determine whether indomethacin is effective in reducing the incidence and severity of heterotopic ossification after surgical management of elbow trauma. METHODS: Between February 2013 and April 2018, 164 eligible patients were randomized to receive postoperative indomethacin or placebo medication. The primary outcome was the incidence of heterotopic ossification on elbow radiographs at 1-year follow-up. Secondary outcomes included the Patient Rated Elbow Evaluation score, Mayo Elbow Performance Index score, and Disabilities of the Arm, Shoulder and Hand score. Range of motion, complications, and nonunion rates were also obtained. RESULTS: At 1-year follow-up, there was no significant difference in the incidence of heterotopic ossification between the indomethacin group (49%) and the control group (55%) (relative risk, 0.89; P = .52). There were no significant differences in postoperative Patient Rated Elbow Evaluation, Mayo Elbow Performance Index, and Disabilities of the Arm, Shoulder and Hand scores or range of motion (P = .16). The complication rate was 17% in both the treatment and control groups (P > .99). There were no nonunions in either group. CONCLUSION: This Level I study demonstrated that indomethacin prophylaxis against heterotopic ossification in the setting of surgically treated elbow trauma was not significantly different from placebo.

Recovery Trajectories Following Complex Elbow Injuries and Radial Head Arthroplasty: A Longitudinal Study Over 8 Years.

PURPOSE: Radial head arthroplasty (RHA) is commonly performed to manage comminuted unreconstructible radial head fractures. Although the outcomes of RHA are often satisfactory, revisions are usually considered when pain intensity is higher than expected. Therefore, it is important to investigate the recovery trajectories of patients following RHA over an extended period and the characteristics that may lead to unfavorable outcomes. METHODS: The Patient-Rated Elbow Evaluation (PREE) was used to assess recovery in 94 patients at baseline (within 2-7 days after surgery); 3 and 6 months; and 1, 2, 3, 4, 5, and 8 years after RHA. Lower PREE values indicate lower pain and disability. Latent growth curve analysis was used to determine classes of recovery. The characteristics of the participants in the identified recovery trajectory classes were then compared. RESULTS: Two distinct recovery trajectories were identified: optimal and suboptimal recoveries. Most patients (84%) belonged to the optimal recovery class, which exhibited significantly lower baseline PREE scores, a consistent pattern of recovery, and a relatively high rate of change. Patients in the suboptimal recovery class (16%) had significantly higher baseline PREE scores and continued to experience relatively higher levels of pain and disability for the duration of the study; their rate of recovery was much slower. Patients belonging to the 2 recovery trajectories did not differ based on age or sex. Although we had low power in other variables, a qualitative exploration showed that the number of current or previous smokers was higher in the suboptimal recovery trajectory class. CONCLUSIONS: In this longitudinal cohort study, we show that high postsurgical pain and disability, and potentially smoking, may adversely affect the recovery trajectory following RHA. Clinicians are recommended to assess these potential factors while considering revision surgeries. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic IV.

Morphology of Proximal Ulna Bare Area: A Guide for Olecranon Osteotomy.

PURPOSE: Olecranon osteotomy is commonly used to obtain access to the distal humerus for fracture fixation. The goal of this study was to accurately describe the anatomy of the bare area to minimize articular cartilage damage while performing olecranon osteotomies. METHODS: Twenty cadaveric ulnae were denuded to expose the bare area. Laser surface mapping was used to create 3-dimensional models, and the nonarticular portions of the ulnae were digitally measured. RESULTS: The morphology of the bare area from all aspects of the proximal ulna was defined. The central bare area was consistent in its location, 4.9 ± 1.5 mm distal to the deepest portion of the trochlear notch and 23.2 ± 2.3 mm distal to the olecranon tip. The maximum chevron osteotomy apical angle to stay within the bare area averaged 110° ± 11.8°. However, there was little tolerance for error without the risk of violating the articular cartilage. With transverse osteotomy, averaging 18° ± 10.6° in the coronal plane, there is less risk of damaging the articular cartilage. CONCLUSIONS: Transverse osteotomy perpendicular to the posterior surface of the ulna aiming at the visible bare area on the medial and lateral sides of the greater sigmoid notch may reduce the chances of violating the nonvisible articular cartilage of the proximal ulna. Based on the findings of this study, if chevron osteotomy is used, a shallow apex distal angle of more than 110° is recommended. CLINICAL RELEVANCE: This study provides intraoperative landmarks to guide surgeons performing olecranon osteotomies to stay within the bare area.

Outcomes of radial head implants in total elbow arthroplasty.

BACKGROUND: There is no consensus on the management of the radial head in total elbow arthroplasty (TEA). In 3-part TEA designs, options include radial head retention, excision, or arthroplasty. Biomechanical studies suggest improved varus-valgus stability with radial head implants in unlinked total elbows. Unfortunately, complications with radial head implants have been common with historical designs. The aim of this study was to evaluate the clinical and radiographic outcomes of radial head implants in a current 3-part TEA and identify risk factors for mechanical failure. METHODS: We performed a retrospective review of radial head implants with a 3-part convertible TEA from 2001 to 2016. Clinical outcomes, functional scores, and radiographic outcomes were recorded. The preoperative radiocapitellar alignment was measured using the radiocapitellar ratio (RCR). Statistics include descriptive statistics, t tests, logistic regression, and Kaplan-Meier survival curves. RESULTS: We identified 44 TEAs in 40 patients, with a mean follow-up period of 7.2 years. The average age at surgery was 58 ± 11 years; 80% of the TEAs were performed in women. The indication for surgery was rheumatoid arthritis in 86%; of the implants, 61% were unlinked. The average preoperative RCR was 10.7 ± 17.9. Postoperatively, 2 radial head implants (5%) were subluxated, 6 (14%) were dissociated, and 2 (5%) were dissociated with implant dislocation on radiographic review. The revision rate for radial head subluxation, dissociation, or dislocation was 7% (n = 3). Univariate logistic regression showed that male sex (P = .002), abnormal preoperative RCR (P = .02), linked implant (P = .03), and older age (P = .04) were risk factors for radial head subluxation, dissociation, or implant dislocation. A multivariate model with all 4 variables did not demonstrate statistical significance. CONCLUSION: The incidence of radial head arthroplasty subluxation, dissociation, or implant dislocation was high (23%). In a univariate logistic regression model, male sex, abnormal preoperative RCR, and linked implants were all statistically significant risk factors for mechanical failure of the radial head implant. Our multivariate model did not show any statistically significant independent risk factors. Polyethylene wear or loosening of the radial head implants was not observed in this study; failure of the bipolar linkage was the principal mode of failure. Although further study is required, caution should be used when considering inserting a radial head implant in male patients with significant preoperative radiocapitellar malalignment. Radial head subluxation or dissociation is not an absolute indication for revision in an asymptomatic patient. Improvements in radial head implant designs in TEA are needed.

The effect of hemiarthroplasty implant modulus on contact mechanics: an experimental investigation.

BACKGROUND: Hemiarthroplasties cause damage to the cartilage that they articulate against, which is a major limitation to their use. This study investigated the use of lower-stiffness materials to determine whether they improve hemiarthroplasty contact mechanics and thus reduce the risk of cartilage damage. METHODS: Eleven fresh-frozen cadaveric upper extremities were disarticulated and fixed in a custom-built jig that applied a static load of 50 N to the radiocapitellar joint. Flexion angles of 0°, 45°, 90°, and 135° were tested with radial head implants made of cobalt-chrome (CoCr) and ultrahigh-molecular-weight polyethylene (UHMWPE) compared with the native radial head. A Tekscan thin-film sensor was used to measure the contact area and contact pressure between the radius and capitellum. RESULTS: UHMWPE and CoCr were too stiff in the application of hemiarthroplasty, resulting in lower contact areas and higher contact pressures relative to the native joint. The native contact area was, on average, 42 ± 20 mm2 larger than that of UHMWPE (P < .001) and 55 ± 24 mm2 larger than that of CoCr (P < .001). UHMWPE had a contact area 13 ± 10 mm2 greater than that of CoCr (P = .014). DISCUSSION AND CONCLUSION: This study shows that even though UHMWPE has a stiffness several times lower than CoCr, the use of this material in hemiarthroplasty led to only a minor improvement in contact mechanics. Neither implant restored contact similar to the native articulation. Investigations into new materials to improve the contact mechanics of hemiarthroplasty should focus on materials with a lower stiffness than UHMWPE.

Computed tomography analysis of the relationship between the coronoid and the radial head.

BACKGROUND: The coronoid process is an important stabilizer of the elbow, and its anatomy has been extensively studied. However, data documenting the relationship of the coronoid relative to the radial head (RH) are limited. The latter is a good landmark for the surgeon when débriding or reconstructing the coronoid. This imaging-based study quantified the anatomic relationship between the coronoid and the proximal radius and ulna. METHODS: We investigated 80 cadaveric upper extremities (18 paired elbows) by 3-dimensional digital analysis of computed tomography data. After construction of a standardized coordinate system, the relationships between the coronoid, the anterior-most point of the RH, the deepest point of the articular surface of the RH, the top of the lesser sigmoid notch, and the deepest point of the guiding ridge of the trochlear notch were analyzed. RESULTS: The mean height of the tip of the coronoid was 36 ± 4 mm (range, 26-43 mm). The mean height of the anterior-most point of the RH was 40 ± 4 mm (range, 28-47 mm). The mean distance between the tip of the coronoid and the anterior-most point of the RH was 4.5 ± 1 mm (range, 2-10 mm). For paired elbows, the heights of the tip of the coronoid and the anterior-most point of the RH were similar between sides. CONCLUSION: This study described the relationship between the coronoid and RH. This information should prove useful when reconstructing a coronoid from a medial approach in the case of an intact RH. The difference in radiographic height between the tip of the coronoid and anterior RH in the normal elbow averages 5 mm. However, when we account for the normal cartilage thickness of the RH and coronoid, a 3- to 6-mm difference in height would be seen at surgery depending on whether the cartilage of the coronoid process is intact or removed. The distance between the tip of the coronoid and the anterior-most point of the RH is similar to the size of shavers used when débriding osteophytes during arthroscopy.

The Unsalvageable Radial Head in Patients Aged 30 Years and Younger.

PURPOSE: Concern exists regarding the use of radial head arthroplasty (RHA) in younger patients. This study assessed clinical, functional, and radiographic outcomes of RHA in patients aged 30 years and younger. METHODS: A retrospective review identified 26 elbows that underwent a smooth stem modular RHA in patients aged 30 years and younger at a median follow-up of 3.3 years clinically and 2.9 years radiographically. The mean age was 24 ± 5 years. Indications were acute trauma in 13 patients and chronic pathologies in the remaining 13, and these 2 groups were evaluated separately. Patients underwent clinical, functional, and radiographic evaluation. RESULTS: Average arc of motion was 137° ± 16° in the cohort with acute trauma and 120° ± 24° in the cohort with chronic pathologies. Mean Patient-Rated Elbow Evaluation scores were 23 ± 18 (acute) and 31 ± 19 (chronic). Mean Quick Disabilities of the Arm, Shoulder, and Hand scores were 18 ± 15 (acute) and 23 ± 20 (chronic). Average Mayo Elbow Performance Index scores were 90 ± 9 (acute) and 80 ± 13 (chronic). Severe capitellar erosion was present in 1 patient (4%) in the cohort with chronic pathologies. Radiographic stem lucency was seen in all cases with 10 of these (38%) graded as severe. Moderate-to-severe ulnohumeral arthritis developed in 4 patients (15%), 3 of whom were in the chronic reconstruction group. Two patients (8%) required reoperation, 1 for persistent instability and 1 for stiffness, both in the cohort with chronic pathologies. CONCLUSIONS: For acute trauma and challenging chronic conditions involving the radial head in patients aged 30 years and younger, a smooth stem modular RHA is an option. Although reoperation rates based on this series are low, osteoarthritis is common when used for posttraumatic conditions and severe radiographic stem lucency was seen in greater than one-third of patients. These concerning features warrant close follow-up, and further long-term outcomes are needed. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Effectiveness of radiographs and computed tomography in evaluating primary elbow osteoarthritis.

BACKGROUND: Preoperative radiographic assessment of osteophyte and loose body locations is critical in planning an arthroscopic débridement for primary elbow osteoarthritis. The purpose of this study was to evaluate the effectiveness of radiographs and computed tomography (CT) in localizing osteophytes and loose bodies. METHODS: A consecutive series of 36 patients with primary elbow osteoarthritis was investigated with radiographs and multiaxial 2-dimensional CT prior to elbow arthroscopy. The location of osteophytes and loose bodies was assessed in 9 anatomic locations by 2 fellowship-trained upper extremity surgeons. The diagnostic effectiveness of both imaging modalities was evaluated by calculating the sensitivity and specificity and compared to the gold standard of elbow arthroscopy. Inter- and intrarater percentage agreement between the observations was calculated using Kappa score. RESULTS: The mean sensitivity for detecting osteophytes in the 9 different anatomic locations was 46% with radiographs and 98% with CT, whereas the mean specificity was 66% and 21% for radiographs and CT, respectively. The mean sensitivity and specificity for loose body detection with radiography were 49% and 89%, respectively, whereas CT had a mean sensitivity of 98% and specificity of 47%. The overall inter-rater percentage agreement between the surgeons in detecting osteophytes and loose bodies on radiographs was 80% and 85%, respectively, whereas on CT it was 95% for detecting osteophytes and 91% for loose bodies. CONCLUSION: CT has greater sensitivity than radiographs for the detection of osteophytes and loose bodies in primary elbow osteoarthritis. The lower specificity of CT may be due to this imaging modality's ability to detect small osteophytes and loose bodies that may not be readily identified during elbow arthroscopy. Radiographs have an inferior inter-rater percentage agreement compared with CT. CT is a valuable preoperative investigation to assist surgeons in identifying the location of osteophytes and loose bodies in patients undergoing surgery for primary elbow osteoarthritis.

Results of Linked Convertible Total Elbow Arthroplasty for the Management of Distal Humeral Fractures in the Elderly.

PURPOSE: Total elbow arthroplasty (TEA) is increasingly used for the management of comminuted distal humeral fractures in elderly patients. There are limited data on the outcome of modern elbow arthroplasty designs in larger patient cohorts. The aim of the current study was to review the outcomes and complications using a cemented convertible TEA system in a linked configuration in patients with distal humeral fractures. METHODS: Patients with distal humeral fractures treated with TEA and a minimum of 2 years' follow-up were reviewed. Demographic information, patient-reported outcome, functional and radiographic outcome assessments, and complications were reported. RESULTS: Forty patients met inclusion criteria; 35 were female. Median follow-up was 4 years (range, 2-13 years). Average age of patients at the index procedure was 79 ± 9 years. All implants were linked. Range of motion was: extension 16° ± 13°, flexion 127° ± 14°, supination 79° ± 11°, and pronation 73° ± 20°. Patient-reported outcome scores were: Patient-Rated Elbow Evaluation 37 ± 35, Quick-Disabilities of the Arm, Shoulder, and Hand 31 ± 31, and Mayo Elbow Performance Index 90 ± 18. Seven patients had heterotopic ossification. Lucent lines were noted predominantly in humeral implant zone V. No lucent lines were noted around the ulnar component in any radiographic zone. Complications occurred in 9 patients (22%) and 2 revisions were performed: one for infection and one for a late periprosthetic fracture. CONCLUSIONS: Total elbow arthroplasty for fracture in elderly patients provides pain relief, functional range of motion, and good patient-reported outcome scores. No implant-related complications of this convertible implant system were encountered, but longer-term follow-up is needed. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Coronoid process reconstruction with a distal clavicle autograft: an in silico analysis of fitting accuracy.

BACKGROUND: The coronoid process plays a vital role in preserving elbow stability. In cases of acute or chronic deficiency of the coronoid process, reconstruction is warranted to restore stability and to avoid early joint degeneration. The distal clavicle might be a useful osteochondral autograft for coronoid reconstruction with low donor-site morbidity. This study evaluated the fitting accuracy of the distal clavicle as an autograft for coronoid process reconstruction. METHODS: One hundred upper-extremity computed tomography scans of 85 body donors were available for this study (mean age, 69 ± 17 years; 46 male and 39 female donors; 15 bilateral specimens). Standardized 40% transverse defects of the coronoid process were digitally created; the distal clavicles were digitally harvested and placed onto the defects by a best-fit technique in 2 different orientations using commercially available software: (1) with the superior aspect of the articular surface of the graft oriented toward the coronoid tip and (2) with the inferior aspect of the articular surface of the graft oriented toward the coronoid tip. The fitting accuracy of the grafts to the native coronoid process was evaluated from lateral to medial using custom code. RESULTS: Regardless of the orientation of the graft, the distal clavicle provided a good fit in the central portion of the coronoid process. In the lateral and medial aspects of the defect, however, the fitting accuracy of the graft declined significantly (P ≤ .044). No significant differences were observed between ipsilateral and contralateral grafts (P ≥ .199). The intrarater reliability was excellent. CONCLUSION: The results of this study suggest that a distal clavicle autograft may be suitable to replace a transverse defect of the coronoid process; however, it may not fully reconstruct the anteromedial and anterolateral aspects of the coronoid.

Medial elbow exposure: an anatomic comparison of 5 approaches.

PURPOSE: Several surgical approaches to the medial elbow are described; however, it remains unclear which exposure provides the optimal view of relevant medial elbow structures. The purpose of this anatomic study was to determine the visible surface area of the coronoid process, distal humerus, and radial head through 5 approaches to the medial elbow. METHODS: Eight fresh-frozen cadaveric upper extremity specimens were dissected. Five surgical approaches were performed on each specimen. The Smith muscle-splitting approach to the ulnar collateral ligament was performed first (Smith), followed by the Hotchkiss medial "Over the top" approach (Hotchkiss), the extended medial elbow approach (EMEA), the flexor carpi ulnaris splitting approach (FCU-Split), and the Taylor and Scham approach (T&S). Bony visualization was determined using laser surface scanning (Artec Space Spider; Artec 3D). The scans were segmented using commercially available digital software (Geomagic Wrap; 3D Systems Corporation), and the surface area visualized was determined. A descriptive analysis of the joint areas visible using the medial collateral ligament (MCL) as a clinical landmark was performed. RESULTS: The EMEA visualized the highest proportion of the total elbow joint from the medial side showing 13.9 ± 6.0 cm2, or 15% ± 4% of the joint. It also provided the best visualization of the coronoid (3.2 ± 1.7 cm2 of surface area, or 26% ± 9%) and distal humerus (9.9 ± 4.3 cm2, or 15% ± 4%). The Hotchkiss approach was best at visualizing the radial head (0.8 ± 0.3 cm2, or 7% ± 3%). The EMEA, Hotchkiss, and Smith approaches showed primarily the anterior bundle of the MCL, its insertion, and the regions anterior to it, whereas the FCU-Split showed the anterior bundle of the MCL and regions both anterior and posterior to it. The T&S showed primarily the areas posterior to the anterior bundle of the MCL; the anterior regions were not visible. The FCU-Split and the T&S allowed visualization of the posterior bundle of the MCL. The intraclass correlation coefficients (ICCs) for intraobserver reliability were 0.997, 0.992, and 0.974 for the test distal humerus, test coronoid, and test radial head, respectively. The ICCs for interobserver reliability were 0.915 for the test distal humerus, 0.66 for the coronoid, and 0.583 for the radial head. CONCLUSION: The EMEA provides the most visualization of the coronoid and distal humerus, whereas the Hotchkiss showed the most radial head. However, these approaches mainly visualize structures anterior to the MCL. If exposure of structures posterior to the MCL is required, the FCU-Split and T&S approaches are more appropriate.

Rotational Anatomy of the Radius and Ulna: Surgical Implications.

PURPOSE: The rotational anatomy of the forearm bones is not well defined. This study aims to further the understanding of the torsion of the radius and ulna to better guide treatment. METHODS: Computed tomography images of 98 cadaveric forearms were obtained and 3-dimensional models of the radius and ulna were generated and analyzed. The rotation of the radius was evaluated by comparing the orientation of the distal radius central axis (DRCA) with the volar cortex of the distal radius (DR) and biceps tuberosity (BT). The rotation of the ulna was evaluated by assessing the orientation of the ulnar head with respect to the proximal ulna. RESULTS: The DR volar cortex pronates from distal to proximal. The BT was 43.8° ± 16.9° supinated from the DRCA (range, 2.7°-86.5°). The mean difference in rotation between contralateral biceps tuberosities was 7.0° ± 7.1°. The volar cortex of the DR was 12.6° ± 5.4° supinated compared with the DRCA. The ulnar head was pronated 8.4° ± 14.9° with respect to the greater sigmoid notch (range, 50.3° pronation-22.0° supination). CONCLUSIONS: The BT has a variable orientation relative to the DR, but it is generally located anteromedially in a supinated arm or 136° opposite the radial styloid. Understanding the rotational anatomy of the radius and ulna can play an important role in surgical planning and implant design. The rotational anatomy of the radius and ulna varies significantly between individuals, but is similar in contralateral limbs. CLINICAL RELEVANCE: Distal radius volar cortex rotational anatomy can help guide treatment of DR fractures and malunions as well as assist in positioning of wrist arthroplasty implants, particularly in the presence of bone loss. The side-to-side similarities demonstrated in this study should be helpful in managing patients with segmental bone loss or fracture malunion and those requiring joint reconstruction.

Elbow motion patterns during daily activity.

BACKGROUND: This in vivo kinematic study was developed to ascertain (1) elbow posture and motion during daily activities and (2) to compare motions of the dominant and nondominant elbows. METHODS: Forty-six subjects wore a custom instrumented shirt to continuously measure elbow posture and motion for the waking hours of 1 day. The 3D orientations of each of the forearm and humerus sensors enabled calculation of elbow flexion-extension and pronation-supination angles. RESULTS: The elbow flexion-extension postures that were most common ranged from 60°-100° for both the dominant and nondominant extremities averaging 44% ± 4% and 35% ± 4% of the day, respectively. When elbow flexion motions were calculated, there were a large number of motions over a wide distribution of flexion angles, with the dominant side exhibiting significantly more motions per hour than the nondominant side. CONCLUSION: Both flexion-extension and pronation-supination motions occur more commonly in the dominant arm, and the dominant arm is more commonly in pronation. These data provide a baseline for assessing treatment outcomes, ergonomic studies, and elbow arthroplasty wear testing.

Effect of ulnar angulation and soft tissue sectioning on radial head stability in anterior Monteggia injuries: an in vitro biomechanical study.

BACKGROUND: Radial head instability continues to be a challenge in the management of anterior Monteggia injuries; however, there is a paucity of literature on the factors that contribute to this instability. The aim of this biomechanical investigation was to examine the effects of ulnar angulation and soft tissue insufficiency on radial head stability in anterior Monteggia injuries. METHODS: Six cadaveric arms were mounted in an elbow motion simulator. Radial head translation was measured during simulated active elbow flexion with the forearm supinated. After testing the elbows in the intact state, the ulna was osteotomized and tested at 0°, 10°, 20°, and 30° of extension angulation. To examine the effect of soft tissue insufficiency, the anterior radiocapitellar joint capsule, annular ligament, quadrate ligament, and the proximal and middle interosseous membrane (IOM) were sequentially sectioned. RESULTS: There was a significant increase in anterior radial head translation with greater ulnar extension angulation. Sequential soft tissue sectioning also significantly increased anterior radial head translation. There was no increase in radial head translation with isolated sectioning of the anterior radiocapitellar joint capsule. Additional sectioning of the annular ligament and quadrate ligament slightly increased anterior radial head translation but did not reach statistical significance. Subsequent sectioning of the proximal and middle IOM resulted in significant increases in anterior radial head translation. CONCLUSION: Our study demonstrates that progressive ulnar extension angulation results in an incremental increase in anterior radial head translation in anterior Monteggia injuries. Moreover, increasing magnitudes of soft tissue disruption result in greater anterior radial head instability.

Management of rheumatoid arthritis of the elbow with a convertible total elbow arthroplasty.

BACKGROUND: Total elbow arthroplasty (TEA) is commonly performed in patients with rheumatoid arthritis (RA). The purpose of this study was to compare outcomes and complications of unlinked and linked TEA using a convertible system in patients with RA. METHODS: All patients with RA who underwent TEA at a single center with a minimum of 2 years' follow-up were reviewed. Demographic information, patient-reported outcome scores, functional outcome assessments, and radiographic parameters were evaluated at most recent follow-up. RESULTS: We evaluated 82 patients (27 with unlinked TEA and 55 with linked TEA) with RA. The mean age at surgery was 61 ± 10 years, with a mean follow-up period of 6 ± 4 years. Demographic characteristics were similar between groups, with the exception of longer follow-up in the unlinked group (8 years vs. 5 years, P = .001). No differences in range of motion were noted. Elbow strength was similar other than pronation strength (74% ± 8% for unlinked vs. 100% ± 8% for linked, P = .03). The mean Mayo Elbow Performance Index was 83 ± 16; Patient Rated Elbow Evaluation score, 15 ± 18; and QuickDASH (short version of the Disabilities of the Arm, Shoulder and Hand questionnaire) score, 34 ± 20. No differences in the rates of reoperation (17% vs. 24%, P = .4), complications (32% vs. 31%, P = .4), or revisions (13% vs. 17%, P = .3) were found between unlinked and linked devices. Four patients with instability, all with unlinked designs, underwent revision to a linked design. Four patients, all with linked designs, underwent revision for aseptic loosening of smooth short-stem ulnar components. CONCLUSION: TEA using a convertible implant design provides good patient-reported outcomes at mid-term follow-up in patients with RA. Our study was unable to detect a difference in the use of either unlinked or linked implant designs; further large comparison trials are needed.

The effect of stem fit on the radiocapitellar contact mechanics of a metallic axisymmetric radial head hemiarthroplasty: is loose fit better than rigidly fixed?

BACKGROUND: Radial head hemiarthroplasty is commonly used to manage comminuted displaced fractures. Regarding implant fixation, current designs vary, with some prostheses aiming to achieve a tight "fixed" fit and others using a smooth stem with an over-reamed "loose" fit. The purpose of this study was to evaluate the effect of radial head hemiarthroplasty stem fit on radiocapitellar contact using a finite element model that simulated both fixed (size-for-size) and loose (1-, 2-, and 3-mm over-reamed) stem fits. It was hypothesized that a loose stem fit would improve radiocapitellar contact mechanics, with an increased contact area and decreased contact stress, by allowing the implant to find its "optimal" position with respect to the capitellum. METHODS: Finite element models of the elbow were produced to compare the effects of stem fit on radiocapitellar contact of a metallic axisymmetric radial head implant. Radiocapitellar contact mechanics (contact area and maximum contact stress) were computed for 0°, 45°, 90°, and 135° of elbow flexion with the forearm in neutral rotation, pronation, and supination. RESULTS: The data suggest that the loose smooth stem radial head implant may be functioning like a bipolar implant in optimizing radiocapitellar contact. Over-reaming of 3 mm produced a larger amount of stress concentration on the capitellum, suggesting there may be a limit to how loose a smooth stem implant should be implanted. CONCLUSIONS: The loose 1 to 2 mm over-reamed stem provided optimal contact mechanics of the metallic axisymmetric radial head implant compared with the fixed stem.

An In Vitro Study to Determine the Effect of Ulnar Shortening on Distal Forearm Loading During Wrist and Forearm Motion: Implications in the Treatment of Ulnocarpal Impaction.

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.

Effect of Radial Lengthening on Distal Forearm Loading Following Simulated In Vitro Radial Shortening During Simulated Dynamic Wrist Motion.

PURPOSE: To evaluate the effect of radial length change on distal forearm loading during simulated dynamic wrist motion. METHODS: A custom-built adjustable radial implant was used to simulate up to 4 mm of distal radius shortening (-4 mm) and 3 mm of lengthening (+3 mm). Load cells were placed in the distal radius and ulna in cadavers to measure their respective axial loads. The specimens were mounted on a wrist motion simulator that produced active wrist motion via tendon actuation. To simulate radial lengthening osteotomy following radial shortening from malunion, the radius was sequentially lengthened by 1-mm intervals from -4 mm to +3 mm. Radial and ulnar loads were measured during simulated wrist flexion, ulnar deviation (UD), and flexion dart throw (DT) at each interval of radial lengthening up to +3 mm. RESULTS: During wrist flexion and UD, for each millimeter of radial lengthening from -4 mm to the native length, there was a significant increase in distal radial loads. No significant change in radial load was observed beyond the native length during flexion and UD. There was no change in distal radial loads during DT for each interval of radial lengthening from -4 mm to +3 mm. A sequential decrease in ulnar loads was observed as the radius was lengthened from -4 mm to +3 mm for all wrist motions evaluated. CONCLUSIONS: Radial lengthening beyond the native length was not detrimental to radial loading and further reduced distal ulnar loading; achieving at least native ulnar variance seems to be appropriate to restore normal biomechanical loading based on this in vitro study. CLINICAL RELEVANCE: Lengthening of the radius beyond native variance in the setting of ulnar impaction syndrome, distal radius malunion, or distal radioulnar instability may not result in excessive loading of the distal radius and further reduces loading on the distal ulna. Surgeons should obtain contralateral wrist x-rays to serve as a template when performing distal radius osteotomies.

Management of chronic distal biceps tendon ruptures: primary repair vs. semitendinosus autograft reconstruction.

BACKGROUND: Delayed presentation of distal biceps tendon ruptures can make primary repair difficult, in which case reconstruction using a tendon graft is an option. The aim of this study was to compare outcomes and complications between delayed distal biceps tendon ruptures managed with repair vs. semitendinosus autograft reconstruction. METHODS: Nineteen delayed distal biceps tendon rupture cases treated with a tendon reconstruction were compared with 16 delayed primary repair cases (>21 days). The reconstructions were performed using a semitendinosus autograft looped through a transosseous tunnel in the bicipital tuberosity and secured with a Pulvertaft weave to the remnant distal biceps tendon. The patient groups were reviewed and completed functional outcomes testing including range of motion, isometric elbow flexion and supination strength, Disabilities of the Arm, Shoulder, and Hand, Patient-Rated Elbow Evaluation, Single Assessment Numeric Evaluation, and Mayo Elbow Performance Index. RESULTS: Mean patient age (49 ± 9 vs. 46 ± 8 years, P = .65) and follow-up (47 ± 25 vs. 45 ± 27 months, P = .45) were similar between delayed primary repair and reconstruction groups. Range of motion (P = .62), supination strength (P = .26), elbow flexion strength (P = .93), Disabilities of the Arm, Shoulder, and Hand (P = .08), and Single Assessment Numeric Evaluation (P = .22) were not significantly different between groups. The Patient-Rated Elbow Evaluation (P = .02) and Mayo Elbow Performance Index (P = .04), however, were better in the delayed repair group compared with the reconstruction group. Complications were similar between groups (P = .87). CONCLUSION: Delayed reconstruction of irreparable distal biceps tendon ruptures with semitendinosus autograft produces similar strength, range of motion, and complication rates but slightly worse functional outcome scores compared with delayed primary repair. This suggests that when possible direct repair is preferred, however, if not possible, reconstruction with an autologous tendon graft results in predictably good outcomes.