Prospective Randomized Trial of Continuous Passive Motion Versus Physical Therapy After Arthroscopic Release of Elbow Contracture

BACKGROUND

Continuous passive motion (CPM) has been used for decades, but we are not aware of any randomized controlled trials (RCTs) in which CPM has been compared with physical therapy (PT) for rehabilitation following release of elbow contracture.

METHODS

In this single-blinded, single-center RCT, we randomly assigned patients undergoing arthroscopic release of elbow contracture to a rehabilitation protocol involving either CPM or PT. The primary outcomes were the rate of recovery and the arc of elbow motion (range of motion) at 1 year. The rate of recovery was evaluated by measuring range of motion at 6 weeks and 3 months. The secondary outcomes included other range-of-motion-related outcomes, patient-reported outcome measures (PROMs), flexion strength and endurance, grip strength, and forearm circumference at multiple time points.

RESULTS

A total of 24 patients were assigned to receive CPM, and 27 were assigned to receive PT. At 1 year, CPM was superior to PT with regard to the range of motion, with an estimated treatment difference of 9° (95% confidence interval [CI], 3° to 16°; p = 0.007). Similarly, the use of CPM led to a greater range of motion at 6 weeks and 3 months than PT. The percentage of lost motion recovered at 1 year was higher in the CPM group (51%) than in the PT group (36%) (p = 0.01). The probability of restoring a functional range of motion at 1 year was 62% higher in the CPM group than in the PT group (risk ratio for functional range of motion, 1.62; 95% CI, 1.01 to 2.61; p = 0.04). PROM scores were similar in the 2 groups at all time points, except for a difference in the American Shoulder and Elbow Surgeons (ASES) elbow function subscale, in favor of CPM, at 6 weeks. The use of CPM decreased swelling and reduced the loss of flexion strength, flexion endurance, and grip strength on day 3, with no between-group differences thereafter.

CONCLUSIONS

Among patients undergoing arthroscopic release of elbow contracture, those who received CPM obtained a faster recovery and a greater range of motion at 1 year, with a higher chance of restoration of functional elbow motion than those who underwent routine PT.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Correlation between hemolytic profile and phylotype of Cutibacterium acnes (formerly Propionibacterium acnes) and orthopedic implant infection

INTRODUCTION

Cutibacterium acnes is a recognized culprit for implant-associated infections, but positive cultures do not always indicate clinically relevant infection. Studies have shown a correlation between the β-hemolytic phenotype of C. acnes and its infectious capacity, but correlation with genetic phylotype has not been performed in literature. The purpose of this study is to evaluate β-hemolysis phenotype, genetic phylotype, and mid-term clinical outcomes of C. acnes isolated from orthopedic surgical sites.

METHODS

Fifty-four C. acnes isolates previously obtained from surgical wounds of patients undergoing hip, knee, shoulder, or spine implant removal were re-cultured. There were 21 females and 33 males with an average age of 59 years (range, 18-84). Twenty-four were from clinically infected sites whereas 30 were considered contaminants. De novo β-hemolysis was analyzed and a retrospective chart review was performed to evaluate clinical outcomes at 7.1 years (range, 0.1-12.8).

RESULTS

On Brucella agar with 5% rabbit blood, 46% of contaminant and 43% of infectious isolates were hemolytic. Type II phylotype was significantly more nonhemolytic regardless of infectious or contaminant status (p < 0.05). Type 1B correlated with a hemolytic-infectious phenotype and Type 1A with a hemolytic-contaminant phenotype but was not statistically significant.

CONCLUSION

The β-hemolytic profile of C. acnes did not correlate with phylotype or clinically relevant orthopedic infection.

Automated three-dimensional measurements of version, inclination, and subluxation

BACKGROUND

Preoperative planning software has been developed to measure glenoid version, glenoid inclination, and humeral head subluxation on computed tomography (CT) for shoulder arthroplasty. However, most studies analyzing the effect of glenoid positioning on outcome were done prior to the introduction of planning software. Thus, measurements obtained from the software can only be extrapolated to predict failure provided they are similar to classic measurements. The purpose of this study was to compare measurements obtained using classic manual measuring techniques and measurements generated from automated image analysis software.

METHODS

Ninety-five two-dimensional computed tomography scans of shoulders with primary glenohumeral osteoarthritis were measured for version according to Friedman method, inclination according to Maurer method, and subluxation according to Walch method. DICOM files were loaded into an image analysis software (Blueprint, Wright Medical) and the output was compared with values obtained manually using a paired sample t-test.

RESULTS

Average manual measurements included 13.8° version, 13.2° inclination, and 56.2% subluxation. Average image analysis software values included 17.4° version (3.5° difference, p < 0.0001), 9.2° inclination (3.9° difference, p < 0.001), and 74.2% for subluxation (18% difference, p < 0.0001).

CONCLUSIONS

Glenoid version and inclination values from the software and manual measurement on two-dimensional computed tomography were relatively similar, within approximately 4°. However, subluxation measurements differed by approximately 20%.

Stem Length and Neck Resection on Fixation Strength of Press-Fit Radial Head Prosthesis: An In Vitro Model

PURPOSE

Various radial head prosthesis designs are currently in use. Few studies compare different prosthetic designs. We hypothesized that increasing a cementless implant stem's length would reduce stem-bone micromotion, with both short and long neck cuts. We also hypothesized that a minimum stem length might be required for the initial fixation strength of a press-fit implant.

METHODS

In 16 fresh-frozen cadaveric elbows (8 pairs), the radial head and neck were cut either 10 or 21 mm below the top of the head. Modular cementless stems were inserted and sequentially lengthened in 5-mm increments. Micromotion under eccentric loading was tested after each incremental change.

RESULTS

Incremental lengthening of the prosthetic stem and the amount of neck resection (10-mm cut vs 21-mm cut) both had a significant effect on micromotion. After a 10-mm radial head-neck resection, we observed a significant decrease in micromotion with stem lengths of 25 mm or greater, whereas with 21 mm of neck resection there was no further reduction in micromotion with increased stem length. These differences can be explained, at least in part, by the concept of the cantilever quotient: the ratio of the head-neck length outside the bone to the total length of the implant.

CONCLUSIONS

The length of the stem affects the initial stability of press-fit radial head prostheses when the level of head and neck resection is at the minimum (ie, 10 mm) for currently available prosthetic designs. At this resection level, stems 25 mm or greater had significantly higher initial stability, but all stem lengths tested had mean micromotion values within the threshold for bone ingrowth.

CLINICAL RELEVANCE

The length of a radial head prosthetic stem affects the initial stability of press-fit radial head prostheses when the level of head and neck resection is at the minimum (ie, 10 mm) for currently available prosthetic designs.

An Anatomic Intraoperatively Prepared Antibiotic Spacer in Two-Stage Shoulder Reimplantation for Deep Infection: The Potential for Early Rehabilitation

Molded antibiotic shoulder spacers allow for intraoperative customization of antibiotics and multiple size options. The purpose of this study was to evaluate the efficacy of an anatomic intraoperatively molded spacer in the two-stage treatment of infection and to assess the safety of early rehabilitation when the capsule and rotator cuff are present. During 2014 and 2015, 27 shoulders were treated with a molded antibiotic cement spacer as part of a two-stage treatment. Indications included periprosthetic joint infection (n=18), native shoulder infection (n=8), and infection after internal fixation (n=1). All patients were followed for a minimum of 2 years. Mean follow-up time was 29.6 months. Patients were allowed to perform motion exercises (group I; n=16) or were instructed to avoid motion (group II; n=11) after spacer implantation, depending on the condition of their rotator cuff. Infection was eradicated in 23 of the 27 shoulders (85%). At most recent follow-up, pain scores were lower in group I. Mean final elevation was 115° in group I compared with 93° in group II. Mean final active external rotation was 36°, with no difference between the groups. In 3 (4%) shoulders with significant proximal humeral bone loss, the spacer became rotationally unstable. An anatomic intraoperatively molded spacer can be implanted safely in two-stage treatment for deep infection and has a reasonable rate of eradication. When adequate capsule and rotator cuff tissue is present, early motion in between stages can be safely recommended with a trend toward improved forward elevation at final follow-up and may facilitate the second stage reimplantation. [Orthopedics. 2019; 42(4):211-218.].

Interobserver and intraobserver comparison of imaging glenoid morphology, glenoid version and humeral head subluxation

BACKGROUND

Glenoid morphology, glenoid version and humeral head subluxation represent important parameters for the treating physician. The most common method of assessing glenoid morphology is the Walch classification which has only been validated with computed tomography (CT).

METHODS

CT images and magnetic resonance imaging (MRI) images of 25 patients were de-identified and randomized. Three reviewers assessed the images for each parameter twice. The Walch classification was assessed with a weighted kappa value. Glenoid version and humeral head subluxation were comparted with a reproducibility coefficient.

RESULTS

The Walch classification demonstrated almost perfect intraobserver agreement for MRI and CT images (k = 0.87). Weighted interobserver agreement values for the Walch classification were fair for CT and MRI (k = 0.34). The weighted reproducibility coefficient for glenoid version measured 9.13 (CI 7.16-12.60) degrees for CT and 13.44 (CI 10.54-18.55) degrees for MRI images. The weighted reproducibility coefficient for percentage of humeral head subluxation was 17.43% (CI 13.67-24.06) for CT and 18.49% (CI 14.5-25.52) for MRI images.

DISCUSSION

CT and MRI images demonstrated similar efficacy in classifying glenoid morphology, measuring glenoid version and measuring posterior humeral head subluxation. MRI can be used as an alternative to CT for measuring these parameters.

Intraobserver and interobserver reliability of the modified Walch classification using radiographs and computed tomography

BACKGROUND

The Walch classification was introduced to classify glenoid morphology in primary glenohumeral osteoarthritis. A modified Walch classification was recently proposed, with 2 additional categories, B3 (monoconcave glenoid with posterior bone loss leading to retroversion > 15° or subluxation > 70%) and D (excessive anterior subluxation), as well as a more precise definition of subtypes A2 and C. The purpose of this study was to evaluate the intraobserver and interobserver agreement of the modified Walch classification system using both plain radiographs and computed tomography (CT).

METHODS

Three fellowship-trained shoulder surgeons blindly and independently evaluated radiographs and CT scans of 100 consecutive shoulders (98 patients) with primary glenohumeral osteoarthritis and classified all shoulders according to the modified Walch classification in 4 separate sessions, each 4 weeks apart. Statistical analysis with the κ coefficient was used to evaluate reliability.

RESULTS

The first reading by the most senior observer on the basis of CT scans was used as the gold standard (distribution: A1, 18; A2, 12; B1, 20; B2, 25; B3, 22; C, 1; and D, 2). The average intraobserver agreement for radiographs and CT scans was 0.73 (substantial; 0.72, 0.74, and 0.72) and 0.73 (substantial; 0.77, 0.69, and 0.72), respectively. The average interobserver agreement was 0.55 (moderate; 0.61, 0.51, and 0.53) for radiographs and 0.52 (moderate; 0.63, 0.50, and 0.43) for CT scans.

CONCLUSION

Intraobserver agreement of the modified Walch classification was substantial both for axillary radiographs and for CT scans. Interobserver agreement was fair. Although the modified Walch classification represents an improvement over the original classification, automated computer-based analysis of CT scans may be needed to further improve the value of this classification.

Validation of a Simple Overlay Device to Assess Radial Head Implant Length

PURPOSE

A simple overlay device (SOD) was developed to measure radial head implant length. The purpose of this study was to determine the accuracy and reliability of this device for measuring experimental radial head implant length.

METHODS

Five fresh frozen cadavers were implanted with sequentially longer implants, adjusted by neck length (0, 2, 4, and 8 mm). Fluoroscopic images were obtained in 4 forearm positions: anteroposterior in supination in full extension, anteroposterior in pronation in full extension, supinated in 45° of flexion, and neutral in 45° of flexion. The SOD measurements (made by 2 observers) were compared with the native original radial head (control) to assess implant length. In addition, gapping of the ulnohumeral joint space was measured for comparison purposes.

RESULTS

The measured radial head and neck lengths for the specimens were 33, 39, 31, 34, and 42 mm. The difference between the actual radial head and neck lengths and those measured with the SOD template averaged less than 2 mm for all 4 collar sizes, except in 1 measurement in which the bicipital tuberosity could not be visualized. The median intraclass correlation coefficients for observer 1 compared with the SOD were 0.94 to 0.99. The median intraclass correlation coefficients between observers were 0.88 to 0.95. For both observers, elbow position, collar height, and the 2 variables combined did not significantly affect the SOD values. The other method that was evaluated, that of measurement of the ulnohumeral joint space, had higher interobserver variability versus the SOD, and allowed detection of lengthening of over 4 mm.

CONCLUSIONS

The SOD is a reliable method for simply assessing radial head length with radiographs and can accurately detect 2 mm or more of proximal radial lengthening.

CLINICAL RELEVANCE

The SOD is a simple and accurate method that can help to optimize radial head sizing.

Anthropometric Study of the Radiocapitellar Joint

PURPOSE

There is scant knowledge about the relationship between the size of the radial head and the size of the capitellum. Also, no data exist comparing the size of the capitellum between the left and the right elbow.

METHODS

Eight pairs of elbows and 12 single elbows from fresh-frozen cadavers were obtained for this study. The vertical height and anterior width of the capitellum were measured with digital calipers. Four different measurements were performed at the radial head: longest outer diameter, shortest outer diameter, the long dish diameter, and short dish diameter. The Pearson intrarater intraclass correlation coefficients were obtained for all measurements.

RESULTS

For the paired elbows, the correlations ranged between 0.95 and 0.96 for the capitellar dimensions and 0.77 and 0.98 for the radial head dimensions. The correlations between the long outer diameter of the radial head with the vertical height and the anterior width of the capitellum were 0.8 and 0.9, respectively.

CONCLUSIONS

There is a high correlation between the long outer diameter of the radial head and the vertical height of the capitellum as well its anterior width. There is also a high correlation between the left and the right elbow.

CLINICAL RELEVANCE

These findings are relevant to radiocapitellar arthroplasty and may be useful for radiocapitellar prosthetic design as well as in the preoperative planning of cases in which the radial head and/or the capitellum is destroyed.

Varus posteromedial rotatory instability: a biomechanical analysis of posterior bundle of the medial ulnar collateral ligament reconstruction

BACKGROUND

Recently, there has been growing interest in the involvement of the posterior bundle of the medial ulnar collateral ligament (pMUCL) in varus posteromedial rotatory instability (PMRI). Varus PMRI has been observed clinically, but the degree of involvement of the pMUCL remains unclear. This study assessed the degree to which the pMUCL is involved in stabilizing the elbow and the feasibility of a pMUCL reconstruction to restore stability.

METHODS

Movements simulating PMRI were performed in 8 cadaveric elbows. Joint gapping values were obtained by 3-dimensional motion capture for the proximal and distal aspects of the ulnohumeral joint. Specimens were assessed at "intact," "cut coronoid + pMUCL," "reconstruction," and "cut anterior aspect MUCL + reconstruction" conditions with mechanical testing at 30°, 60°, and 90° of elbow flexion.

RESULTS

Proximal joint gapping significantly increased from intact to cut coronoid + pMUCL at 60° and 90°, and distal joint gapping significantly increased at 90°. In the reconstruction condition, joint gapping across the proximal joint at 60° and 90° significantly recovered, as did distal joint gapping at 90°. In the cut anterior aspect MUCL + reconstruction condition, no significant increase occurred in proximal or distal joint gapping.

CONCLUSIONS

Transection of the pMUCL with a coronoid fracture leads to increased joint gapping, suggesting the presence of PMRI. PMRI can still occur with an intact lateral ligamentous complex. A pMUCL tendon graft reconstruction confers some elbow stability in this injury mechanism.

Reverse Shoulder Arthroplasty With Proximal Humeral Replacement for the Management of Massive Proximal Humeral Bone Loss

Background

Substantial proximal humeral bone loss may compromise reverse shoulder arthroplasty secondary to limited implant support, insufficient soft tissue tension due to shortening, lack of attachment sites for the posterosuperior cuff when present, and lack of lateral offset of the deltoid. In these circumstances, use of a proximal humeral replacement may be considered.

Patients/Methods

Between 2012 and 2014, 34 consecutive reverse shoulder arthroplasties were performed using a proximal humeral replacement system. The indications were failed shoulder arthroplasty (15), oncology reconstruction (9), humeral malunion/nonunion (7), prior resection arthroplasty (2), and intraoperative fracture (1). All patients were included in the survival analysis. Twenty-two patients with minimum 2-year follow-up were included in analysis of clinical results.

Results

Among the cohort of 34 patients, there were 8 additional reoperations: humeral loosening (3), periprosthetic fracture (2), irrigation and debridement (2), and glenoid loosening (1). Humeral component loosening occurred exclusively in patients undergoing revision shoulder arthroplasty. The 4 patients had an average 3.75 prior procedures before the proximal humeral replacement. Two of the revisions were from cemented to uncemented stems. Among the 23 patients with minimum 2-year follow-up, there was significant improvement in pain scores (4.1 vs 0.6), forward elevation (31 vs 109) degrees, and 81% were satisfied.

Conclusion

Use of a proximal humeral replacement when performing a reverse shoulder arthroplasty in the complex setting of substantial proximal humerus bone loss provides good clinical results and a particularly low dislocation rate. However, the rate of loosening of the humeral component in the revision setting suggests that proximal humeral replacement components should be cemented when revising a previously cemented stem.

IRB

16-006966.

The Posterior Bundle's Effect on Posteromedial Elbow Instability After a Transverse Coronoid Fracture: A Biomechanical Study

PURPOSE

There has been increased interest in the role of the posterior bundle of the medial collateral ligament (pMUCL) in the elbow, particularly its effects on posteromedial rotatory stability. The ligament's effect in the context of an unfixable coronoid fracture has not been the focus of any study. The purposes of this biomechanical study were to evaluate the stabilizing effect of the pMUCL with a transverse coronoid fracture and to assess the effect of graft reconstruction of the ligament.

METHODS

We simulated a varus and internal rotatory subluxation in 7 cadaveric elbows at 30°, 60°, and 90° elbow flexion. The amount of ulnar rotation and medial ulnohumeral joint gapping were assessed in the intact elbow after we created a transverse coronoid injury, after we divided the pMUCL, and finally, after we performed a graft reconstruction of the pMUCL.

RESULTS

At all angles tested, some stability was lost after cutting the pMUCL once the coronoid had been injured, because mean proximal ulnohumeral joint gapping increased afterward by 2.1, 2.2, and 1.3 mm at 90°, 60°, and 30°, respectively. Ulnar internal rotation significantly increased after pMUCL transection at 90°. At 60° and 30° elbow flexion, ulnar rotation increased after resection of the coronoid but not after pMUCL resection.

CONCLUSIONS

An uninjured pMUCL stabilizes against varus internal rotatory instability in the setting of a transverse coronoid fracture at higher flexion angles. Further research is needed to optimize graft reconstruction of the pMUCL.

CLINICAL RELEVANCE

The pMUCL is an important secondary stabilizer against posteromedial instability in the coronoid-deficient elbow. In the setting of an unfixable coronoid fracture, the surgeon should examine for posteromedial instability and consider addressing the pMUCL surgically.

The effect of a radial neck notch on press-fit stem stability: a biomechanical study on 7 cadavers

BACKGROUND

Minimal micromotion is necessary for osteointegration of cementless radial head prostheses. When radial head fractures extend longitudinally, where the neck cut for prosthetic replacement should be made is uncertain. We hypothesized that complete resection of the notched portion of a radial neck confers no advantage in initial stability compared with not resecting the defect and inserting the implant into a notched radial neck.

MATERIALS AND METHODS

The radii of 7 cadavers underwent radial head resection and implantation with a 25-mm-long press-fit radial head stem. Before implantation, a 5-mm-long notch that was less than 1-mm wide was made in the radial neck. After the stem-bone micromotion was recorded, the proximal 5 mm of radial neck, incorporating the entire notch, was cut away, the stem was inserted 5 mm further, and the resulting micromotion was recorded.

RESULTS

The mean micromotion measured in the presence of a cortical notch was 51 ± 6 µm. After the neck was circumferentially cut and the stem was advanced, the micromotion (46 ± 9 µm) was not statistically significantly different.

DISCUSSION

Initial stability of an adequately sized cementless stem in the presence of a 5-mm-long cortical notch was well within the threshold needed for bone ingrowth (<100 µm). In addition, there was no reduction of micromotion after the notch-containing portion of the radial neck was resected and the stem was advanced. Making a neck cut distal to a 5-mm-long, 1-mm-wide cortical notch does not confer added stability. Thus, surgeons can preserve bone stock and avoid an aggressive neck cut.

Management of Failed Rotator Cuff Repair in Young Patients

Management of failed rotator cuff repair may be very difficult, especially in young patients. Various nonmodifiable and modifiable patient factors, including age, tendon quality, rotator cuff tear characteristics, acute or chronic rotator cuff tear, bone quality, tobacco use, and medications, affect rotator cuff repair healing. Surgical variables, such as the technique, timing, tension on the repair, the biomechanical construct, and fixation, as well as the postoperative rehabilitation strategy also affect rotator cuff repair healing. Variable outcomes have been reported in patients who undergo revision rotator cuff repair; however, a systematic surgical approach may increase the likelihood of a successful outcome. Numerous cellular and mechanical biologic augments, including platelet-rich plasma, platelet-rich fibrin matrix, mesenchymal stem cells, and acellular dermal matrix grafts, have been used in rotator cuff repair; however, conflicting or inconclusive outcomes have been reported in patients who undergo revision rotator cuff repair with the use of these augments. A variety of tendon transfer options, including latissimus dorsi, teres major, lower trapezius, pectoralis minor, pectoralis major, combined pectoralis major and latissimus dorsi, and combined latissimus dorsi and teres major, are available for the management of massive irreparable rotator cuff tears. Ultimately, the optimization of surgical techniques and the use of appropriate biologic/tendon transfer techniques, if indicated, is the best method for the management of failed rotator cuff repair.

Patient-Physician Agreement Using Summary Outcome Determination Scores

OBJECTIVE

To determine whether the Summary Outcome Determination (SOD) score had exhibited a high level of physician-patient agreement in surgical patients.

PATIENTS AND METHODS

The medical records of 320 postoperative patients were reviewed, of whom 164 patients were included in the study. Patients were included if both physician-assigned and patient-assigned SOD scores had been recorded. The SOD is administered as follows: the patient is asked "Compared to before surgery, is your elbow/shoulder better, worse or no different?" If better: "Is it improved, greatly improved, almost normal or normal?" If worse: "Is it worse or profoundly worse, or as bad as dying?" Each category is associated with a numerical value and definition for further clarification. The patient is asked to assign a category and a numerical value after the physician has already done so. These categories and values were evaluated between raters (ie, physician and patient) to assess reliability.

RESULTS

The intraclass correlation coefficient of physician-patient numerical ratings was "excellent" (0.93). The Bland-Altman 95% limits of agreement on the differences between the physician and the patient ranged from -1.3 to 1.3. The physician and patient numerical rankings matched exactly in 118 patients (72%) or differed by a factor of no more than 1 (26%) in 161 (98%) patients.

CONCLUSION

The SOD score can be used as both a surgeon-based and a patient-based outcome score, given the high level of agreement. Given its brevity, ease of understanding, and high interrater reliability, the SOD has the potential to be used across multiple specialties to rate outcomes.

The Influence of Incision Type on Patient Satisfaction After Plate Fixation of Clavicle Fractures

BACKGROUND

Open reduction and internal fixation (ORIF) of the clavicle is a common procedure that has been shown to have improved outcomes over nonoperative treatment. Several incisions can be used to approach clavicle fractures, the decision of which is variable among surgeons.

PURPOSE

To compare patient satisfaction and subjective outcomes between patients with a longitudinal incision versus those with a necklace incision for the treatment of diaphyseal clavicle fractures.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Thirty-six patients with a diaphyseal clavicle fracture (Orthopaedic Trauma Association type 15-B) were treated by 1 of 7 orthopaedic surgeons. The intervention was ORIF with anatomic contoured plates. Patients were divided into a necklace incision group and a longitudinal incision group depending on the surgical approach used. Medical records were reviewed, and participants completed an online survey with questions related to pain, numbness, scar appearance, and satisfaction. Function was assessed using the American Shoulder and Elbow Surgeons score. Statistical significance was determined with P < .05.

RESULTS

There were 16 patients in the necklace incision group and 20 in the longitudinal incision group. Patients in the necklace incision group were significantly more satisfied with the appearance of their scars (P = .01), which correlated with overall satisfaction (P = .05). There were no differences in overall satisfaction, pain, numbness, or reoperation rates for hardware removal between the necklace (6%) and longitudinal groups (15%).

CONCLUSION

Patients undergoing clavicle ORIF with a necklace incision are more satisfied with their scar appearance than those with a longitudinal incision. The overall satisfaction, rate of numbness, and plate removal were similar in both groups.

The results of tension band rotator cuff suture fixation of locked plating of displaced proximal humerus fractures

INTRODUCTION

The purpose of this study was to assess 1-year outcomes of patients with displaced proximal humerus fractures who underwent treatment with locked plate fixation with rotator cuff suture augmentation.

METHODS

A total of 86 patients who had sustained 2, 3 and 4-part displaced proximal humerus fractures underwent locked plate fixation with multiple sutures placed in the cuff tendons. Clinical outcome variables included active forward elevation (AFE), active external rotation (AER), and Constant and American Shoulder and Elbow Surgeons (ASES) scores. Post-operative variables included the following complications: varus re-collapse, loss of fixation, osteonecrosis of the humeral head (AVN), screw cut out, hardware failure and infection.

RESULTS

Forty-one patients were available with minimum of 1-year follow-up. Mean AFE was 142±17.0° and AER was 41±13.0°. The overall complication rate was 14.6%, with osteonecrosis being the most common (12.2%). Of the 21 patients (51.2%) that initially had varus displacement, all but one maintained anatomic reduction and fixation. Mean ASES score was 78.2±20.0 and average Constant score was 72.7±17.6. Bivariate analyses demonstrated that pre-operative medial comminution (p=0.297) or varus collapse (p=0.95) were not associated with an increased likelihood of sustaining a complication.

CONCLUSIONS

Follow-up of patients in this series demonstrated a low overall complication rate and excellent functional outcomes. We believe suture augmentation of the rotator cuff can counteract varus forces on proximal humerus fractures fixed with locked plates, and should be performed routinely in displaced 2, 3 and 4 part fractures.

Importance of the posterior bundle of the medial ulnar collateral ligament

BACKGROUND

There has been a renewed interest in the pathomechanics of elbow dislocation, with recent literature having suggested that the medial ulnar collateral ligament is more often disrupted in dislocations than the lateral ligamentous complex. The purpose of this serial sectioning study was to determine the influence of the posterior bundle of the medial ulnar collateral ligament (pMUCL) as a stabilizer against elbow dislocation.

METHODS

An elbow dislocation was simulated in 5 cadaveric elbows by mechanically applying an external rotation moment and valgus force. Medial ulnohumeral joint gapping was measured at 30°, 60°, and 90° of flexion in an intact elbow after sectioning of the medial collateral ligament's anterior bundle (aMUCL) and then after sectioning of the pMUCL as well.

RESULTS

After sectioning of the aMUCL, the pMUCL was able to stabilize the joint against dislocation. After aMUCL sectioning, the proximal joint space significantly increased by 4.2 ± 0.6 mm at 30° of flexion and 2.6 ± 0.3 mm at 60° of flexion, although it did not dislocate. The gapping increase of 0.9 ± 0.6 at 90° of flexion did not reach significance. After sectioning of the pMUCL (after having already sectioned the aMUCL), all of the specimens frankly dislocated at all flexion angles.

CONCLUSIONS

An intact pMUCL can prevent elbow dislocation and limited joint subluxation to within 6.6 mm. Our findings indicate that repair or reconstruction may be warranted in certain circumstances (ie, residual instability after operative management of a terrible triad injury or after aMUCL reconstruction).

Hemiarthroplasty versus reverse shoulder arthroplasty for treatment of proximal humeral fractures: a meta-analysis

BACKGROUND

We performed a meta-analysis of studies with at least Level IV evidence to compare outcomes between hemiarthroplasty and reverse shoulder arthroplasty for the treatment of proximal humeral fractures.

METHODS

Three electronic databases (PubMed, Cochrane, and EMBASE) were searched. The quality of each study was investigated, and data on radiographic and functional outcomes were extracted and analyzed.

RESULTS

The analysis included 1 Level I study, 1 Level II study, 3 Level III studies, and 2 Level IV studies. Reverse shoulder arthroplasty was more favorable than hemiarthroplasty in forward elevation (P < .001), abduction (P < .001), tuberosity healing (P = .002), Constant score (P < .001), American Shoulder and Elbow Surgeons score (P < .001), and Disabilities of the Arm, Shoulder and Hand score (P = .001). Only external rotation (P = .85) was not in favor of reverse shoulder arthroplasty.

CONCLUSIONS

The available literature suggests that reverse shoulder arthroplasty performed to address complex proximal humeral fractures might result in more favorable clinical outcomes than hemiarthroplasty performed for the same indication.

Heterotopic ossification formation after fracture-dislocations of the elbow

BACKGROUND

Heterotopic ossification (HO) is a serious complication of traumatic elbow injuries, particularly fracture-dislocations. Limited data exist in the literature regarding the risk factors associated with HO formation in these injuries. The purpose of this study was to review the incidence of HO after fracture-dislocation of the elbow and to identify potential risk factors associated with its formation.

METHODS

Twenty-seven patients (28 elbows) were surgically treated for elbow fracture-dislocations during 8 years, with an average follow-up of 14 months. Records were reviewed with attention paid to several factors: demographic data, comorbidities, time interval from injury to surgical intervention, number of closed reductions attempted before surgery, surgical approach, management of the radial head, treatment of the anterior capsular injury, and coronoid fixation.

RESULTS

Of the 28 elbows, 12 (43%) developed HO postoperatively; 9 of 28 elbows underwent multiple attempted closed reductions before definitive surgical stabilization, with HO formation in 7 of the 9 (77%). Time to surgery, age, gender, radial head fixation or replacement, coronoid open reduction and internal fixation, capsular repair, and medical comorbidities were not found to influence HO formation, although the performance of multiple reductions was identified as a risk factor.

DISCUSSION

HO developed in 77% of patients with multiple attempted closed reductions. We found a 43% incidence of HO in patients surgically treated for elbow fracture-dislocations. Neither time to surgery after the injury nor demographic or other factors relating to the manner in which associated osseous or soft tissue injuries were managed influenced the formation of HO.

A novel approach for coronoid fractures

The coronoid process serves as an important constraint that provides ulnohumeral joint stability. We describe a novel approach to coronoid fractures that minimizes surgical dissection, without compromising fracture visualization. We present the case of a 65-year-old woman who sustained an anteromedial facet fracture of the coronoid process. The elbow demonstrated intractable posteromedial instability and the inability to maintain reduction even up to 90 degrees. This report describes a surgical approach to the coronoid process that minimizes extensive soft tissue dissection. It is a variation of the previously described approach by Taylor and Scham, although it can achieve a similar exposure without elevation of the entirety of the flexor-pronator mass. Our approach involves a limited skin incision, followed by elevation of enough of the flexor-pronator mass such that adequate visualization of the posterior medial collateral ligament (which was repaired), anteromedial facet, and the fractured fragment of coronoid were achieved. Moreover, this approach enables the course of the ulnar nerve to remain unaltered.

Snapping popliteus tendon within an osteochondritis dissecans lesion: an unusual case of lateral knee pain

The popliteus muscle is an important structure in the posterior knee, coursing from the distal lateral femoral condyle to the posterior tibia, and it initiates knee flexion, protects the lateral meniscus, and resists tibial external rotation. Abnormalities in the lateral femoral condyle may result in impaired tracking of the popliteus tendon over the lateral femoral condyle, causing pain and a snapping sensation. We report a case of a snapping popliteus tendon caused by an osteochondral defect of the lateral femoral condyle. We obtained a thorough medical history, performed a detailed physical examination, and performed diagnostic ultrasonography to accurately diagnose the condition. The patient underwent open popliteus tenotomy and tibial tenodesis with excellent results and full return to activity. Any abnormality of the lateral femoral condyle may predispose patients to snapping popliteus tendon and we believe early diagnosis utilizing ultrasonography imaging and surgical intervention may benefit these patients significantly.

Canal preparation for prosthetic radial head replacement: rasping versus reaming

BACKGROUND

While many design-specific features of radial head prostheses have been studied (ie, geometry and surface coating), the optimum technique for canal preparation has not been determined. We hypothesized that preparation of the radial canal with a reamer would allow for the accommodation of a larger stem diameter versus following canal preparation with a rasp, and would provide acceptable stem-bone micromotion.

METHODS

Paired proximal radii from 7 cadavers were prepared by a rasp on one side and a reamer on the contralateral side. Cementless radial head stems of increasing diameter were sequentially implanted up to the maximum size or until a fracture occurred and the micromotion between the stem and bone was recorded.

RESULTS

In 3 of 5 pairs, at least a 1 mm larger stem size fit into the canal after reaming versus after rasping (P = .04). 5 of 7 radii fractured secondary to intentional stem oversizing. For the optimally-sized stems, similar micromotion values were observed whether the canal was rasped (41 ± 6 μm) or reamed (44 ± 6 μm) (P = .72).

DISCUSSION

This study investigated an aspect of radial head arthroplasty technique about which little has currently been published. It is possible that use of a reamer rather than a rasp, while providing similar initial stability, might expand the stem size options for initial press-fit stability, and decrease the risk of fracture.

CONCLUSION

Radial canal preparation with a reamer allows for implantation of a 1 mm larger stem diameter versus rasping, while providing comparable initial stability to that achieved after rasping.

Effect of stem length on prosthetic radial head micromotion

BACKGROUND

Osteointegration of press-fit radial head implants is achieved by limiting micromotion between the stem and bone. Aspects of stem design that contribute to the enhancement of initial stability (ie, stem diameter and surface coating) have been investigated. The importance of total prosthesis length and level of the neck cut has not been examined.

METHODS

Cadaveric radii were implanted with cementless, porous-coated radial head stems. We resected 10, 12, 15, 20, and 25 mm of radial neck in each specimen. Stem-bone micromotion was measured after each cut. Values were expressed in terms of quotients (cantilever quotient).

RESULTS

A threshold effect was observed at 15 mm of neck resection (cantilever quotient, 0.4), with a significant increase in micromotion observed between 12 mm (40 ± 10 μm) and 15 mm (80 ± 25 μm). A cantilever quotient of 0.35 or less predicted implant stability, whereas implants with a cantilever quotient of 0.6 or more were unstable. In between, the stems were "at risk" of instability.

CONCLUSION

Initial stem stability of a porous-coated, cementless radial head implant is dependent on length of the implant stem within bone and the level of the cut (amount of bone resected). Stability may be compromised by an implant with a combined head and neck length that is too long compared with the stem length within the canal. We found a critical ratio of exposed prosthesis to total implant length (cantilever quotient of 0.4), which puts the prosthesis at risk of inadequate initial stability. These data carry important implications for implant design and use.

Stress shielding around radial head prostheses

PURPOSE

Stress shielding is known to occur around rigidly fixed implants. We hypothesized that stress shielding around radial head prostheses is common but nonprogressive. In this study, we present a classification scheme to support our radiographic observations.

METHODS

We reviewed charts and radiographs of 86 cases from 79 patients with radial head implants from both primary and revision surgeries between 1999 and 2009. Exclusion criteria included infection, loosening, or follow-up of less than 12 months. We classified stress shielding as: I, cortical thinning; II, partially (IIa) or circumferentially (IIb) exposed stem; and III, impending mechanical failure.

RESULTS

Of 26 well-fixed stems, 17 (63%) demonstrated stress shielding: I = 2, II = 15 (IIa = 12, IIb = 3), and III = 0. We saw stress shielding with all stem types: cemented or noncemented; long or short; and straight, curved, or tapered. The only significant difference was that stems implanted into the radial shaft had less stress shielding than stems implanted into the neck or tuberosity (P = .03). The average follow-up was 33 months (range, 13-70 mo). Stress shielding was detectable by an average of 11 months (range, 1-15 mo). The pattern of bone loss was similar in 16 of 17 cases (94%), starting on the outer periosteal cortex. The 3 cases with circumferential exposure of the stem (stage IIb) averaged 2.6 mm (range, 1-4 mm) of exposed stem. Stress shielding never extended to the bicipital tuberosity, and there were no cases of impending mechanical failure.

CONCLUSIONS

Stress shielding around radial head prostheses is common, regardless of stem design. However, it is typically minor, nonprogressive, and of questionable clinical consequence.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Effects of rasp mismatch on plasma spray radial head stems

BACKGROUND

Radial head prosthetic stems designed for bone ingrowth are available with both plasma spray and grit blasted surfaces. A recent study comparing micromotion between the 2 demonstrated greater micromotion in the plasma spray than grit blasted stems, even though the latter had lower surface roughness. This raised the question that perhaps the size mismatch for grit-blasted radial head stems (0.5 mm) might be inadequate for plasma spray stems.

HYPOTHESIS

A tighter initial press-fit with plasma spray radial head stems may be gained by preparation with an undersized rasp.

METHODS

Paired cadaveric radii were implanted with plasma spray stems. The surgical control was prepared with a rasp designated for its corresponding stem size ("size-matched"), while the experimental group was prepared with a rasp 0.5 mm smaller than designated ("undersized").

RESULTS

The micromotion for the undersized rasp group (46 ± 12 μm) was not significantly different than for the size-matched rasp group (21 ± 12 μm) (P = .1).

DISCUSSION

Contrary to our hypothesis, no reduction in micromotion was observed when using an undersized rasp with a plasma spray stem. The micromotion results were not different from those observed when using a size-matched rasp, and actually approached significance in the opposite direction. This may be due to the rough stem surface chipping away bone fragments, rather than the bone being cut away precisely as is done with a rasp.

CONCLUSION

The use of an undersized rasp prior to implantation of a plasma spray radial head prosthesis does not confer any added benefit in terms of initial stability.

Effect of radial head malunion on radiocapitellar stability

BACKGROUND

Management for Mason type II radial head fractures is controversial. We hypothesized that angulation or depression of a marginal radial head fragment would affect radiocapitellar stability similarly to fragment excision.

MATERIALS AND METHODS

A Mason type II radial head fracture was created in 6 cadaveric elbows by excising a segment from the anterolateral quadrant that was 30% of the diameter of the articular surface. Radiocapitellar stability was recorded under 5 sets of conditions: (1) intact radial head (intact), (2) 30% surface area fragment resected (partially excised), (3) anatomic fragment fixation with screws (fixed), (4) fragment fixation with 2 mm of depression relative to the articular surface (depressed), and (5) fragment fixation after a 30° wedge resection (angulated).

RESULTS

The forces required to subluxate the joint were greatly reduced after fragment excision (5 ± 1 N; P = .0001) and restored to normal (21 ± 1 N; P = .9) after anatomic fixation of the excised fragment. The peak forces were significantly reduced with fragment depression (4 ± 1 N) and angulation (4 ± 2 N; P = .0001).

CONCLUSION

A radial head fracture that is depressed 2 mm or angulated 30° may cause up to an 80% loss of concavity-compression stability of the radiocapitellar joint.

Distal biceps tendon rupture: an in vitro study

BACKGROUND

Options for repair of distal biceps tendon ruptures are well-described. However, scant data exist in the literature regarding failure strength of the native tendon. We hypothesize that a) the distal biceps tendon failure strength is sensitive to loading angle, and b) the failure strength is greater than what has been previously reported in the literature.

METHODS

15 radii were potted in a simulated supine position, and the native tendon was pulled from the tuberosity at angles of 90, 60, and 30° of flexion (5 per group) relative to the long axis of the radius. The failure load and stiffness were recorded and compared.

FINDINGS

The native tendon's mean failure load tended to increase as flexion angle decreased. Due to the large variability in strength, mean failure loads of the 90° (mean 358 (SE 117N)), 60° (mean 617 (SE 141N)), and 30° (mean 762 (SE 130N)) groups were not statistically different from each other (P=0.12). The mean stiffness results for each group (mean 501 (SE 176N/mm), mean 763 (SE 226N/mm), and mean 756N (SE 179N/mm), respectively) were not significantly different from each other (P>0.6).

INTERPRETATION

The load to failure of the distal biceps tendon may be higher than what has previously been reported, and may be dependent on the elbow flexion angle. Though this difference may be attributed to the difference in methodology it should be taken into account during consideration of repair and rehabilitation.

Influence of prosthetic design on radiocapitellar concavity-compression stability

BACKGROUND

Radial head prostheses are available with multiple geometric properties. The effect of design features on radiocapitellar stability has not been investigated.

HYPOTHESIS

The shape (depth and radius of curvature) of the articulating dish of a radial head prosthesis affects radiocapitellar stability.

MATERIALS AND METHODS

Radiocapitellar stability due to concavity-compression was evaluated in 8 fresh frozen elbows before and after radial head replacement with 2 different designs of radial head implants (RH 1 and RH 2). Both functioned as monopolar implants. Peak forces resisting subluxation and force-displacement characteristics were compared between the 2 and to the native radial head.

RESULTS

Radial head design significantly affected radiocapitellar stability. RH 1, which had a deeper dish than RH 2, required significantly higher peak forces to subluxate the radiocapitellar joint. The peak subluxation forces and the slopes of the force-displacement curves were not significantly different from the native radial head for RH 1, but they were for RH 2.

CONCLUSION

The shape of the articular dish (depth, radius of curvature) of a monopolar radial head implant affects its contribution to radiocapitellar stability. An implant that mimics normal anatomy is more effective than a shallow radial head implant with a radius of curvature that is longer than normal.

Micromotion of plasma spray versus grit-blasted radial head prosthetic stem surfaces

BACKGROUND

Initial stability of a textured surface prosthetic stem is necessary for bone in-growth. Surfaces currently used for radial head prostheses include titanium plasma spray and grit-blasted titanium.

HYPOTHESIS

Plasma spray radial head prosthetic stems are less dependent than grit-blasted stems on a tight press fit. Good initial press-fit stability, with acceptable micro-motion, can be achieved with a greater range of stem sizes using a plasma spray than grit-blasted surface.

METHODS

Paired cadaveric radii were implanted with plasma spray or grit-blasted radial head prosthetic stems. Micromotion at the stem tip was measured under circumstances simulating eccentric loads.

RESULTS

Micromotion in the plasma spray (PS) stems (49 ± 37) μm was not better than that in the grit-blasted (GB) stems (28 ± 10) μm (P = .13). Micromotion of less than 100 μm was measured in all 12 GB stems that were maximum or 1 mm less than maximum size, versus 5/6, and 4/6 PS stems, respectively.

DISCUSSION

Micromotion in plasma spray prosthetic radial head stems was not better than that seen in grit-blasted stems, contrary to our initial hypothesis.

CONCLUSION

Grit-blasted prosthetic radial head stems confer initial press-fit stability that is as good as, or slightly better than, corresponding plasma spray stems. Acceptable amounts of micromotion can be achieved with 2 grit-blasted stem sizes and probably with 2 plasma spray stem sizes.

Radiocapitellar stability: the effect of soft tissue integrity on bipolar versus monopolar radial head prostheses

INTRODUCTION

Radiocapitellar stability depends, in part, on concavity-compression mechanics. This study was conducted to examine the effects of the soft tissues on radiocapitellar stability with radial head prostheses.

HYPOTHESIS

Monopolar radial head implants are more effective in stabilizing the radiocapitellar joint than bipolar radial head prostheses, with the soft tissues intact or repaired.

MATERIALS AND METHODS

Twelve fresh frozen elbow specimens were used to evaluate radiocapitellar stability with monopolar and bipolar radial heads. The study variables focused on varying soft tissue conditions and examined the mean peak subluxation forces put forth by each prosthesis design.

RESULTS

With the soft tissues intact, the mean peak force resisting posterior subluxation depended significantly on the radial head used (P = .03). Peak force was greatest for the native radial head (32 ± 7 N) and least with the bipolar prosthesis (12 ± 3 N), with the monopolar prosthesis falling in between (21 ± 4 N). The presence of soft tissues significantly affected the bipolar implant's ability to resist subluxation, though it did not significantly impact the native or monopolar radial heads.

DISCUSSION

This study reveals the dependence of radiocapitellar stability on soft tissue integrity, particularly for bipolar prostheses. Overall, monopolar prostheses have a better capacity to resist radiocapitellar subluxation.

CONCLUSION

From a biomechanical perspective, the enhancement of elbow stability with a monopolar radial head prosthesis is superior to that with a bipolar design. This is especially true when the integrity of the soft tissues has been compromised, such as in trauma.