Morphological characteristics of fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow: a three-dimensional CT remodeling study.

BACKGROUND: Fractures of the anteromedial facet of the coronoid in posteromedial rotatory instability of the elbow are classified into 3 subtypes based on their location. The purpose of this study was to analyze the fracture morphology of anteromedial facet fractures in their 3 subtypes (anteromedial rim, anteromedial rim + tip, and anteromedial rim + sublime tubercle [±tip]). METHODS: Three-dimensional computed tomography remodeling was used to evaluate anteromedial facet fractures in a consecutive series of 40 patients, all of whom were affected by posteromedial rotatory instability of the elbow. Characteristics of the fractures, including the number of fragments, size of fragments, plane of the fracture line, and involvement of the sublime tubercle and radial notch, were measured for each subtype of the anteromedial facet fractures. RESULTS: Each subtype had a typical fracture pattern and distinct size. The fracture subtype 1 showed a single-fragment fracture, subtype 2 showed either a single- or dual-fragment fracture, and subtype 3 showed either a dual- or triple-fragment fracture. The angle between the fracture line and the coronal plane was greatest in subtype 3 fractures. The surface area of the fragment was largest in subtype 3 fractures. The percentages of articular involvement of the sublime tubercle were 0% in subtype 1, 47% in subtype 2, and 79% in subtype 3. The percentages of articular involvement of the radial notch were 0% in subtype 1, 7% in subtype 2, and 8% in subtype 3. CONCLUSION: Analysis with quantitative 3-dimensional computed tomography showed the characteristic morphology of each subtype of anteromedial facet fracture. Subtype 1 comprised 1 fragment with the smallest fragment size. Subtype 2 was a single- or dual-fragment fracture, the size of which should be considered in the treatment plan. Subtype 3 was a large fragment comprising the sublime tubercle. Our findings are significant because they highlight unique fracture morphology that may help surgeons to distinguish one fracture subtype from another in clinical practice.

Comparison of Ulnar Collateral Ligament Reconstruction Techniques in the Elbow of Sports Players.

Ulnar collateral ligament injuries have been increasingly common in overhead throwing athletes. Ulnar collateral ligament reconstruction is the current gold standard for managing ulnar collateral ligament insufficiency, and numerous reconstruction techniques have been described. Although good clinical outcomes have been reported regarding return to sports, there are still several technical issues including exposure, graft selection and fixation, and ulnar nerve management. This review article summarizes a variety of surgical techniques of ulnar collateral ligament reconstructions and compares clinical outcomes and biomechanics.

Relationship between the tilt angle of bipolar radial head prostheses and radiological radiocapitellar instability.

OBJECTIVE: This study aimed to radiologically assess the relationship between the tilt angle of the bipolar radial head prostheses and radiocapitellar instability. METHODS: In this radiological study, 28 consecutive patients (13 females and 15 males: mean age=47 years and age range=23-77 years) who underwent cemented bipolar radial head arthroplasty (Judet CRF II) because of comminuted radial head fracture with elbow instability were retrospectively reviewed. RESULTS: There was excellent intra- and interobserver reliability for the measurements of the tilt angle and the radiocapitellar distance. ICC for interobserver reliability of the tilt angle was 0.93, and ICC for intraobserver reliability for the 2 observers was 0.96 and 0.97, respectively. ICC for interobserver reliability of the radiocapitellar distance was 0.87, and ICC for intraobserver reliability for the 2 observers was 0.91 and 0.93, respectively. The mean tilt angle was 17.6° (range=1°-35°), and the mean radiocapitellar distance was 8 mm (range=1-17 mm). Pearson's correlation revealed a strong significant positive correlation between the tilt angle and the radiocapitellar distance (r=0.77 and p<0.001). CONCLUSION: Evidence from this study has demonstrated a strong positive correlation between the tilt angle of bipolar radial head prostheses and radiocapitellar instability. The tilt angle can be used as an indicator of radiocapitellar joint instability following bipolar radial head prostheses. LEVEL OF EVIDENCE: Level IV, Diagnostic study.

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.

Pseudotumor and Subsequent Implant Loosening as a Complication of Revision Total Hip Arthroplasty with Ceramic-on-Metal Bearing: A Case Report.

Pseudotumors are not uncommon complications after total hip arthroplasty (THA) and may occur due to differences in bearing surfaces of the head and the liner ranging from soft to hard articulation. The most common causes of pseudotumors are foreign-body reaction, hypersensitivity and wear debris. The spectrum of pseudotumor presentation following THA varies greatly-from completely asymptomatic to clear implant failure. We report a case of pseudo-tumor formation with acetabular cup aseptic loosening after revision ceramic-on-metal hip arthroplasty. The patient described herein underwent pseudotumor excision and re-revision complex arthroplasty using a trabecular metal shell and buttress with ceramic-on-polyethylene THA. Surgeons should be aware of the possibility of a pseudotumor when dealing with revisions to help prevent rapid progression of cup loosening and implant failure, and should intervene early to avoid complex arthroplasty procedures.

Healing Process of Osteonecrotic Lesions of the Femoral Head Following Transtrochanteric Rotational Osteotomy: A Computed Tomography-Based Study.

BACKGROUND: Transtrochanteric rotational osteotomy (TRO) is a controversial hip-preserving procedure with a variable success rate. The healing process of femoral head osteonecrosis after TRO has been poorly explained till now. This study aimed to evaluate the healing process of previously transposed necrotic lesion after a TRO for nontraumatic osteonecrosis of the femoral head using computed tomography (CT). METHODS: Among 52 patients (58 hips) who had preserved original femoral head after TRO, we retrospectively reviewed 27 patients (28 hips) who had undergone sequential CT scans and had no major complication following TRO. The average age was 34 years (range, 18 to 59 years). The mean follow-up period was 9.1 years. We evaluated the reparative process of the transposed osteonecrotic lesion with CT scans. RESULTS: Plain radiographs of the osteonecrotic lesion revealed sclerotic and lucent changes in 14 hips (50%) and normal bony architecture in the other 14 hips (50%) at the final follow-up. CT scans of the osteonecrotic lesions showed cystic changes with heterogeneous sclerosis in 13 hips (46%), normal trabecular bone with or without small cysts in 9 hips (32%), and fragmentation of the necrotic lesion in 6 hips (22%). Seventeen hips (60%) showed minimal (13 hips) to mild (4 hips) nonprogressive collapse of the transposed osteonecrotic area. The collapse of the transposed osteonecrotic area on the CT scan was significantly associated with the healing pattern (p = 0.009), as all 6 patients (6 hips) with fragmentation of the necrotic lesion had minimal (5 hips) to mild (1 hip) collapse. Furthermore, a significant association was found between the collapse of the transposed osteonecrotic area on the CT scan of 17 hips (60%) and postoperative Harris hip score (p = 0.021). We observed no differences among the healing patterns on CT scans with regard to age, gender, etiology, staging, preoperative lesion type, preoperative intact area, percentage of necrotic area, direction of rotation and immediate postoperative intact area. CONCLUSIONS: The majority of the hips showed incomplete regeneration of the transposed osteonecrotic lesion with cysts, sclerosis, and fragmentation, whereas repair with normal trabecular bone was observed only in one-third of the hips that were preserved after Sugioka TRO.

Is two-stage reimplantation effective for virulent pathogenic infection in a periprosthetic hip? A retrospective analysis.

AIM: To investigate the effectiveness of two-stage reimplantation using antibiotic-loaded bone cement (ALBC) and the risk factors associated with failure to control periprosthetic joint infection (PJI). METHODS: We retrospectively reviewed 38 consecutive hips managed using two-stage reimplantation with ALBC. The mean follow-up period was 5.4 years (range: 2.5-9 years). RESULTS: The causative pathogens were isolated from 29 patients (76%), 26 of whom were infected with highly virulent organisms. Sixteen patients (42%) underwent at least two first-stage debridements. An increased debridement frequency correlated significantly with high comorbidity (P < 0.001), a lower preoperative Harris hip score (HHS; P < 0.001), antimicrobial resistance, and gram-negative and polymicrobial infection (P = 0.002). Of the 35 patients who underwent two-stage reimplantation, 34 showed no signs of recurrence of infection. The mean HHS improved from 46 ± 12.64 to 78 ± 10.55 points, with 7 (20%), 12 (34%), 11 (32%) and 5 (14%) patients receiving excellent, good, fair and poor ratings, respectively. CONCLUSION: The current study demonstrated that two-stage reimplantation could successfully treat PJI after hip arthroplasty. However, the ability of ALBC to eradicate infection was limited because frequent debridement was required in high-risk patients (i.e., patients who are either in poor general health due to associated comorbidities or harbor infections due to highly virulent, difficult-to-treat organisms). LEVEL OF EVIDENCE: Level IV.

Can pelvic tilting be ignored in total hip arthroplasty?

INTRODUCTION: The orientation of acetabular component is influenced by pelvic tilt, body position and individual variation in pelvic parameters. Most post-operative adverse events may be attributed to malposition of the component in the functional position. There is evidence that orientation of the pelvis changes from the supine to standing position. Authors report a case of recurrent dislocation after total hip arthroplasty due to excessive pelvic tilting. PRESENTATION OF CASE A 69-year old female with coxarthrosis had undergone total hip replacement with recurrent dislocation of the hip on bearing weight in spite of using constrained acetabular component. DISCUSSION: Our case report substantiates the influence of pelvic tilt, incurred by a sagittal deformity of spine, on dynamic orientation of the acetabular cup which was positioned in accordance with the anatomic landmarks alone. If the reference is only bony architecture and dynamic positions of the pelvis are not taken into account, improper functional orientation of the acetabular cup can result in sitting and standing positions. These can induce instability even in anatomically appropriately oriented acetabular component. CONCLUSION: The sagittal position of pelvis is a key factor in impingement and dislocation after total hip arthroplasty. Pelvic tilting affects the position of acetabular component in the sagittal plane of the body as compared with its anatomic position in the pelvis. We suggest a preoperative lateral view of spine-pelvis, in upright and supine position for evaluation of a corrective adaptation of the acetabular cup accordingly with pelvic balance.

Clinical results after arthroscopic treatment for septic arthritis of the elbow joint.

PURPOSE: The purpose of this study was to examine clinical findings of septic arthritis of the elbow joint in a series of immunocompetent patients and to evaluate the outcomes after arthroscopic treatment. METHODS: Between October 2006 and January 2012, 11 patients with septic arthritis of the elbow underwent arthroscopic surgery. History, laboratory findings, and radiologic findings were reviewed. Functional outcomes were evaluated using the Mayo Elbow Performance Score (MEPS). RESULTS: The study included 5 men and 6 women with a mean age of 45 years. An underlying medical disease was present in 1 patient (diabetes). Staphylococcus aureus was the most common organism identified (5 patients). There was 1 reoperation and no complications related to the arthroscopic procedure. Eight of 11 patients had excellent results assessed by MEPS at the final follow-up. The mean MEPS was 94.5 at the final follow-up. CONCLUSIONS: Septic arthritis of the elbow joint can occur in otherwise healthy patients without pre-existing elbow disease. Arthroscopic irrigation and synovectomy are safe and effective in patients with septic arthritis and result in good functional outcomes. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Minimally invasive plate osteosynthesis using a helical plate for metadiaphyseal complex fractures of the proximal humerus.

Minimally invasive plate osteosynthesis (MIPO) has been used for humeral shaft fractures, but concerns exist about soft tissue injuries. The purpose of this study was to report the surgical technique and clinical outcomes of MIPO using a helical plate for metadiaphyseal complex humeral shaft fractures. Twelve patients with acute displacement involving proximal and middle third humeral shaft fractures (AO type C) were treated using the MIPO technique with a helical plate. Fracture union, complications, and functional outcomes were evaluated using the Constant-Murley score and Mayo Elbow Performance Score (MEPS) at final follow-up. All fractures united at an average of 17.9 weeks. No major complications, such as neurovascular injury, infection, and nonunion, were observed. Mean Constant-Murley and MEPS scores at final follow-up were 88.6 and 97.9, respectively. A MIPO technique using a helical plate can be a useful surgical option for metadiaphyseal complex fractures of the humeral shaft.

Can ulnar variance be used to detect overstuffing after radial head arthroplasty?

BACKGROUND: Overstuffing of the radiocapitellar joint during metallic radial head arthroplasty has been reported to cause loss of elbow flexion, capitellar erosion, and early-onset osteoarthritis. Although this is known, there is no agreed-on measurement approach to determine whether overstuffing has occurred. QUESTIONS/PURPOSES: We therefore hypothesized that overlengthening the radial head during radial head arthroplasty changes the ulnar variance in the wrist. METHODS: Seven cadaveric radii were implanted with radial head prostheses of increasing thickness. Each specimen was implanted successively with increasingly thick radial head prostheses measuring 2, 4, and 6 mm thicker than the native radial head, and radiographs were taken after implantation of each prosthesis. The ulnar variance with each prosthesis was measured using the method of perpendiculars. RESULTS: The ulnar variance of the native and 2-mm (p = 0.04), 4-mm (p = 0.008), and 6-mm (p = 0.008) overly thick radial head prosthesis-implanted states decreased significantly with each incremental increase in prosthetic head thickness. CONCLUSIONS: Implantation of thicker radial head prostheses decreased the ulnar variance. Our results indicate ulnar variance could be used to detect overstuffing of radial head prostheses. CLINICAL RELEVANCE: The simplicity and reliability of ulnar variance make it a potentially useful indicator of overlengthening after radial head arthroplasty.

Non surgically managed anteromedial coronoid fractures in posteromedial rotatory instability: three cases with 2 years follow-up.

Varus posteromedial rotatory instability refers to one of the complex elbow fracture-dislocation caused by anteromedial coronoid fracture with disruption of lateral collateral ligament (LCL). Recent clinical and biomechanical studies have demonstrated that this unstable complex injury resulted in incongruence of joint, which could lead to early posttraumatic arthritis. With reports of poor result after conservative treatment, surgical treatment including anteromedial fixation and LCL repair has been strongly recommended to achieve stable joint. This case series describes three patients with anteromedial coronoid fracture who were managed conservatively with excellent outcomes. This report suggests that anteromedial coronoid fracture associated with posteromedial rotatory instability might be treated using conservative treatment in selective cases when anteromedial coronoid fracture is minimally displaced and there is no evidence of elbow subluxation.

Radial head prosthesis micromotion characteristics: Partial versus fully grit-blasted stems.

BACKGROUND: Compared to fully textured prosthetic stems, partial texturing lessens bone loss due to stress shielding and makes removal easier. However, initial press-fit stability is necessary for bone ingrowth. HYPOTHESIS: There is no significant difference in the initial stability of radial head prostheses that are partially grit-blasted compared to those that are fully grit-blasted. MATERIALS AND METHODS: Cadaveric radii were implanted with partial or fully grit-blasted radial head prostheses. Micromotion of the stem at the isthmus of the canal and stem tip were measured under circumstances simulating eccentric loads. RESULTS: Micromotion was not significantly different in the fully grit-blasted stems (isthmus, 11 ± 1 µm; tip, 21 ± 2 µm) and partially grit-blasted stems (isthmus, 13 ± 2 µm; tip, 25 ± 2 µm) (P = 0.4). The direction of loading had no effect on micromotion characteristics in either the fully or partially grit-blasted stems (P = .07). DISCUSSION: Micromotion is comparable in partially and fully grit-blasted radial head prosthetic stems. For both stem surfaces, micromotion was well within the range that is conducive for bone ingrowth. A partially textured stem might have less bone loss due to stress shielding, making it easier to remove without destroying bone. CONCLUSION: The initial stability of a radial head stem that is partially grit-blasted only at the proximal end is comparable to that of a radial head stem that is grit-blasted along its entire length.

Simple overlay device for determining radial head and neck height.

BACKGROUND: The purpose of this study was to test the hypothesis that a simple overlay device can be used on radiographs to measure radial head and neck height. MATERIALS AND METHODS: Thirty anteroposterior elbow radiographs from 30 patients with a clinical diagnosis of lateral epicondylitis were examined to measure radial head and neck height. Three methods using different points along the bicipital tuberosity as a landmark were used. Method 1 used the proximal end of the bicipital tuberosity, method 2 used the most prominent point of the bicipital tuberosity, and method 3 used a simple overlay device (SOD) template that was aligned with anatomic reference points. All measurements were performed three times by three observers to determine interobserver and intraobserver reliability. RESULTS: Intraclass correlation coefficients revealed higher interobserver and intraobserver correlations for the SOD template method than for the other two methods. The 95% limits of agreement between observers were markedly better (-1.8 mm to +1.0 mm) for the SOD template method than for the proximal point method (-3.8 mm to +3.4 mm) or the prominent point method (-5.9 mm to +4.9 mm). CONCLUSIONS: We found that the SOD template method was reliable for assessing radial head and neck height. It had less variability than other methods, its 95% limit of agreement being less than 2 mm. This method could be helpful for assessing whether or not the insertion of a radial head prosthesis has resulted in over-lengthening of the radius.

Stem diameter and micromotion of press fit radial head prosthesis: a biomechanical study.

BACKGROUND: Aseptic loosening of the stem, ranging from mild periprosthetic lucency to symptomatic loosening leading to implant removal, has been reported in press fit radial head prostheses. HYPOTHESIS: The purpose of this study was to determine the effect of the stem diameter and insertion force on initial stability with a press fit radial head prosthesis designed for bone ingrowth. MATERIALS AND METHODS: Cadaveric radii were implanted with radial head prostheses of increasing stem diameter. The insertion forces for each rasp and stem were measured. Micromotion of the stem at the isthmus of the canal and stem tip were measured under circumstances simulating eccentric loads. RESULTS: Insertion forces for all submaximum-sized rasps were similar. However, the insertion force for the maximum-sized rasp was approximately twice as large, and the insertion force for the oversized rasp was twice as large again, potentially indicating that the insertion force may be useful as a guide for determining appropriate stem size. Micromotions of the maximum diameter stem (isthmus, 41 microm; tip, 64 microm) were near the threshold for bone ingrowth, whereas the micromotions of the submaximum stem (isthmus, 253 microm; tip, 394 microm) were above this threshold. DISCUSSION: The maximum diameter stem achieved greater stability (minimum micromotion) compared with the submaximum diameter stem. CONCLUSION: The best fixation strength in the press fit radial head prosthesis was achieved by maximum sizing in the neck canal.

Radiocapitellar joint stability with bipolar versus monopolar radial head prostheses.

BACKGROUND: Bipolar and monopolar designs are both available for replacement of the radial head. Few data exist comparing the biomechanical characteristics of these 2 quite different prostheses. This study evaluated the relative contribution to radiocapitellar stability by concavity compression with these 2 types of radial head prostheses. METHODS: The study used 12 fresh frozen elbow cadavers. The capitellum of the distal humerus and 3 different conditions of radial head (native, monopolar and bipolar) were tested for radiocapitellar joint stability. RESULTS: The monopolar metallic head and the native radial head behaved similarly regarding resistance to subluxation. The bipolar head behaved in an entirely opposite manner than the native and monopolar head and actually acted to facilitate subluxation. CONCLUSIONS: Mobility of radial head components, such as in the bipolar radial head, has a compromising effect on the concavity compression stability of the radiocapitellar joint. A monopolar implant is more effective in stabilizing the radiocapitellar joint than a bipolar radial head prosthesis.

Arthroscopic removal of the failed silicone radial head prosthesis.

Although silicone radial head arthroplasty has been successful in many patients, it has been associated with complications such as fractures of the prosthesis and silicone synovitis. Synovectomy and removal of the failed silicone radial head, with or without reimplantation of a metallic radial head, is indicated in such complications. In an effort to perform minimally invasive surgery, we performed arthroscopic removal of the silicone head combined with synovectomy in a series of such patients. The silicone prostheses were cut into two or three pieces and then removed. After a median follow up of 26 months, all patients reported excellent pain relief and there were no residual loose bodies. Removal of a failed silicone radial head can be successfully performed arthroscopically. This arthroscopic technique has the advantage of being minimally invasive and can be combined with other procedures including capsulectomy, if necessary.

Optimal screw orientation for fixation of coronoid fractures.

OBJECTIVE: The aim of this study was to compare the fixation stability of coronoid fractures achieved by a screw inserted in the anteroposterior (AP) direction with that achieved by a screw inserted in the posteroanterior (PA) direction. METHODS: Eleven pairs of fresh-frozen cadaveric ulna were used. A coronoid fracture was simulated by transverse osteotomy at the midpoint of coronoid height. The specimens of a pair were then randomized to be fixed with an AP screw in one specimen and a PA screw in the other. Insertion torque, load to failure, and stiffness were measured under axial load with a material testing machine. RESULTS: PA screw placement yielded greater strength and stiffness of fixation than did AP placement. The mean load to failure was 184 N in the PA screw group and 131 N in the AP screw group (P < 0.05). The mean stiffness was 106 N/mm with PA screws and 76 N/mm with AP screws (P < 0.05). These differences were statistically significant despite the fact that the screw insertion torques was similar in PA screw (0.27 Nm) and AP screw (0.25 Nm) (P = 0.2). CONCLUSIONS: PA screw placement was biomechanically superior to AP screw placement. Together with the fact that it is clinically easier to insert and remove screw from the posterior ulna, these data indicate that optimal screw orientation for fixation of coronoid tip fracture is posterior to anterior direction.

Pelvic osteolysis relationship to radiographs and polyethylene wear.

The relationship of radiographic pelvic osteolysis to computed tomographic (CT) volume and polyethylene wear remains controversial. We evaluated the sensitivity and specificity of radiographs in detecting osteolysis considering CT scan as the true value, in 118 hips with cementless cups. Correlation between osteolysis volume in CT, area of osteolysis in radiograph, and linear wear of polyethylene was assessed. The sensitivity and specificity of anteroposterior radiographs for detection of osteolysis was 57.6% and 92.9%, respectively. Addition of oblique radiographs increased the sensitivity to 64.4% without changing the specificity. The sensitivity increased to 92.8% for lesion more than 1000 mm(3). There was good correlation between 2-dimensional (2D) osteolytic area in radiograph and 3-dimensional (3D) volume (r = 0.74) in CT scan and linear wear of polyethylene showed good correlation with 3D CT volume (r = 0.62) and 2D area in radiograph (r = 0.60). Thus radiographs are useful to screen clinically significant osteolysis.