Is the contralateral tibia a reliable template for reconstruction: a three-dimensional anatomy cadaveric study.

PURPOSE: The contralateral anatomy is regularly used as a reconstruction template for corrective osteotomies of several deformities and pathological conditions. However, there is lack of evidence that the intra-individual differences between both tibiae are sufficiently small to use the contralateral tibia as a 3D reconstruction template for complex osteotomies. The aim of this study was to evaluate the intra-individual side differences of the tibia in length, torsion, angulation, and translation using 3D measurement techniques. METHODS: 3D surface models of both tibiae were created from computed tomography data of 51 cadavers. The (mirrored) models of the right tibiae were divided into two halves at the centre of the shaft. Thereafter, the proximal and distal segments were aligned to the left (contralateral) tibia in an automated fashion. The relative 3D transformation between both aligned segments was measured to quantify the side difference in 6° of freedom (3D translation vector, 3 angles of rotation). RESULTS: The mean side difference in tibia length was 2.1 mm (SD 1.3 mm; range 0.2-5.9 mm). The mean side difference in torsion was 4.9° (SD 4.1°; range 0.2°-17.6°). The mean side difference in the coronal and sagittal planes was 1.1° (SD 0.9°; range 0.0°-4.6°) and 1.0° (SD 0.8°; range 0.1°-2.9°), respectively. CONCLUSION: The present study confirms small side differences in torsion between the left and right tibia, while the side differences in the coronal and sagittal plane are probably negligible. The contralateral tibia seems to be a reliable reconstruction template for the 3D preoperative planning of complex corrective osteotomies of the tibia. However, torsional differences should be interpreted with caution, as a single cut-off value of a clinically relevant torsional side difference cannot be defined. The presented results are relevant to surgeons considering the contralateral tibia as a 3D reconstruction template for corrective osteotomies of the tibia. LEVEL OF EVIDENCE: Basic science.

Long-term results of total elbow arthroplasty in patients with hemophilia.

HYPOTHESIS: It was hypothesized that the long-term survivorship and clinical outcome are reasonable, justifying total elbow arthroplasty (TEA) in patients with end-stage hemophilic arthropathy. METHODS: From 2002 to 2012, 13 primary TEAs (Coonrad-Morrey design) were implanted in 9 consecutive patients with an average age of 55 (range, 39-76) years. Type A hemophilia was diagnosed in 7 patients and type B hemophilia in 2 patients. Clinical and radiographic results of all (11 TEAs) but 1 patient were retrospectively analyzed. RESULTS: After a mean of 9.1 (range, 5-14) years, the mean visual analog scale score for pain, total Mayo Elbow Performance Score, and subjective elbow value were significantly improved from 5 (standard deviation, ±3) to 2 (±2; P = .007) points, from 64 (±16) to 89 (±11; P = .008) points, and from 47% (±15%) to 81% (±11%; P < .001), respectively. Whereas the flexion arc remained unchanged (P = .279), mean active pronation improved significantly (P = .024). Postoperative complications were recorded in 8 TEAs (62%), whereas 5 TEAs (38%) underwent partial component exchange after a mean of 7.2 (range, 3-10) years: 2 for periprosthetic infection, 2 for polyethylene wear, and 1 for humeral component loosening. Of the living patients after partial component exchange (n = 3), the mean final total Mayo Elbow Performance Score, flexion and rotation arc, visual analog scale score for pain, and subjective elbow value were comparable with the results of the living patients without revision surgery (n = 8). CONCLUSIONS: TEA for patients with advanced hemophilic arthropathy is associated with a substantial complication and revision rate. However, even after revision without implant removal, it provides good functional and subjective long-term results.

Total knee arthroplasty in patients with a history of illicit intravenous drug abuse.

PURPOSE: Injection drug users are at high risk for both infection with blood-borne pathogens, namely, human immune deficiency virus (HIV), hepatitis-B, -C virus, various bacterial infections, as well as early primary and secondary joint degeneration. When total knee arthroplasty (TKA) is anticipated the risk of septic complications is a major concern. The purpose of this study was to assess the clinical and radiographic outcome of patients with a history of intravenous drug use after total knee arthroplasty. The primary outcome was revision rate. Secondary outcomes were the Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Society Score (KSS) and radiographic loosening. METHODS: We retrospectively reviewed the records of 1,692 TKA performed or revised in our institution. Data of 18 TKA in 12 patients (11 male, 1 female; average age 42, range 23-62 years) with a history of intravenous opioid abuse were available for final analysis. RESULTS: The mean follow up was 125 (range 25-238) months. Seven patients required revision surgery due to periprosthetic joint infection after 62 months (range 5-159): one two staged revision, three arthrodesis and three amputations. The median prosthesis survival was 101 (95%-CI 48-154) months. CONCLUSION: Total knee arthroplasty in patients with a history of intravenous drug abuse is associated with major complications, including above-the-knee amputation. If permanent abstinence from intravenous drug abuse is doubtful, other therapeutic options including primary arthrodesis should be considered.

Is Increased Acetabular Cartilage or Fossa Size Associated With Pincer Femoroacetabular Impingement?

BACKGROUND: Surgical treatment for pincer femoroacetabular impingement (FAI) of the hip remains controversial, between trimming the prominent acetabular rim and reverse periacetabular osteotomy (PAO) that reorients the acetabulum. However, rim trimming may decrease articular surface size to a critical threshold where increased joint contact forces lead to joint degeneration. Therefore, knowledge of how much acetabular articular cartilage is available for resection is important when evaluating between the two surgical options. In addition, it remains unclear whether the acetabulum rim in pincer FAI is a prominent rim because of increased cartilage size or increased fossa size. QUESTIONS/PURPOSES: We used reformatted MR and CT data to establish linear length dimensions of the lunate cartilage and cotyloid fossa in normal, dysplastic, and deep acetabula. METHODS: We reviewed the last 200 hips undergoing PAO, reverse PAO, and surgical dislocation for acetabular rim trimming at one institution. We compared MR images of symptomatic hips with acetabular dysplasia (20 hips), pincer FAI (29 hips), and CT scans of asymptomatic hips from patients who underwent CT scans for reasons other than hip pain (20 hips). These hips were chosen sequentially from the underlying pool of 200 potential subjects to identify the first 10 male and the first 10 female hips in each group that met inclusion criteria. As a result of low numbers, we included all hips that had undergone reverse PAO and met inclusion criteria. Cartilage width was measured medially from the cotyloid fossa to the lateral labrochondral junction. Cotyloid fossa linear height was measured from superior to inferior and cotyloid fossa width was measured from anterior to posterior. Superior lunate cartilage width (SLCW) and cotyloid fossa height (CFH) were measured on MR and CT oblique coronal reformats; anterior lunate cartilage width (ALCW), posterior lunate cartilage width (PLCW), and cotyloid fossa width (CFW) were measured on MR and CT oblique axial reformats. Cohorts were compared using multivariate analysis of variance with Bonferroni's adjustment for multiple comparisons. RESULTS: Compared with control acetabula, dysplastic acetabula had smaller SLCW (2.08 ± 0.29 mm versus 2.63 ± 0.42 mm, mean difference = -0.55 mm; 95% confidence interval [CI] = -0.83 to -0.27; p < 0.01), ALCW (1.20 ± 0.34 mm versus 1.64 ± 0.21 mm, mean difference = -0.44 mm; 95% CI = -0.70 to -0.18; p = 0.00), CFH (2.84 ± 0.37 mm versus 3.42 ± 0.57 mm, mean difference = -0.59 mm; 95% CI = -0.96 to -0.21; p < 0.01), and CFW (1.98 ± 0.50 mm versus 2.77 ± 0.33 mm, mean difference = -0.80 mm; 95% CI = -1.16 to -0.42; p < 0.0001). Based on the results, we identified two subtypes of deep acetabula. Compared with controls, deep subtype 1 had normal CFH and CFW but increased ALCW (2.09 ± 0.42 mm versus 1.64 ± 0.21 mm; p < 0.001) and PLCW (2.32 ± 0.36 mm versus 2.00 ± 0.32 mm; p = 0.04). Compared with controls, deep subtype 2 had increased CFH (4.37 ± 0.51 mm versus 3.42 ± 0.57 mm; p < 0.01) and CFW (2.76 ± 0.54 mm versus 2.77 ± 0.33 mm; p = 1.0) but smaller SCLW (2.12 ± 0.40 mm versus 2.63 ± 0.42 mm; p < 0.01). CONCLUSIONS: Deep acetabula have two distinct morphologies: subtype 1 with increased anterior and posterior cartilage lengths and subtype 2 with a larger fossa in height and width and smaller superior cartilage length. CLINICAL RELEVANCE: In patients with deep subtype 1 hips that have increased anterior and posterior cartilage widths, rim trimming to create an articular surface of normal size may be reasonable. However, for patients with deep subtype 2 hips that have large fossas but do not have increased cartilage widths, we propose that a reverse PAO that reorients yet preserves the size of the articular surface may be more promising. However, these theories will need to be validated in well-controlled clinical studies.

Postoperative alignment of TKA in patients with severe preoperative varus or valgus deformity: is there a difference between surgical techniques?

BACKGROUND: There have been conflicting studies published regarding the ability of various total knee arthroplasty (TKA) techniques to correct preoperative deformity. The purpose of this study was to compare the postoperative radiographic alignment in patients with severe preoperative coronal deformity (≥10° varus/valgus) who underwent three different TKA techniques; manual instrumentation (MAN), computer navigated instrumentation (NAV) and patient specific instrumentation (PSI). METHODS: Patients, who received a TKA with a preoperative coronal deformity of ≥10° with available radiographs were included in this retrospective study. The groups were: MAN; n = 54, NAV; n = 52 and PSI; n = 53. The mechanical axis (varus / valgus) and the posterior tibial slope were measured and analysed using standing long leg- and lateral radiographs. RESULTS: The overall mean postoperative varus / valgus deformity was 2.8° (range, 0 to 9.9; SD 2.3) and 2.5° (range, 0 to 14.7; SD 2.3), respectively. The overall outliers (>3°) represented 30.2% (48 /159) of cases and were distributed as followed: MAN group: 31.5%, NAV group: 34.6%, PSI group: 24.4%. No significant statistical differences were found between these groups. The distribution of the severe outliers (>5°) was 14.8% in the MAN group, 23% in the NAV group and 5.6% in the PSI group. The PSI group had significantly (p = 0.0108) fewer severe outliers compared to the NAV group while all other pairs were not statistically significant. CONCLUSIONS: In severe varus / valgus deformity the three surgical techniques demonstrated similar postoperative radiographic alignment. However, in reducing severe outliers (> 5°) and in achieving the planned posterior tibial slope the PSI technique for TKA may be superior to computer navigation and the conventional technique. Further prospective studies are needed to determine which technique is the best regarding reducing outliers in patients with severe preoperative coronal deformity.

Long-term results of total knee arthroplasty in haemophilic patients: an 18-year follow-up.

PURPOSE: Total knee arthroplasty (TKA) for patients with end-stage haemophilic arthropathy is considered to be a successful procedure with satisfying mid- to long-term results. It was the purpose of this study to provide clinical and radiological long-term results of TKAs implanted in a consecutive cohort of haemophilic patients. METHODS: Primary TKA was performed in 43 consecutive knees in 30 haemophilic patients. After a mean of 18 (SD ± 4) years, 15 patients (21 knees) with a mean age of 58 (SD ± 8) years were available for follow-up. The outcome was assessed using the Knee Society score, WOMAC, SF-36, Kaplan-Meier survivorship analysis as well as radiographic evaluation of radiolucency. RESULTS: In 13 (30%) of the 43 consecutive knees, revision surgery was necessary due to infection or aseptic loosening, among which eight (19%) due to aseptic loosening and five (12%) due to haematogenous infection. The calculated 20-year survival rates with revision for any reason or infection as the end points were 59 and 82%, respectively. All patients with the primary TKA in situ observed progressive radiolucent lines around the implants at the final follow-up. The Knee Society clinical and functional score significantly improved from pre- (36 points; SD ± 16 and 62 points; SD ± 19) to post-operatively (73 points; SD ± 15 and 78 points; SD ± 18; p < 0.001). Eighty-six per cent rated their result as either good or excellent. Whereas flexion did not improve, flexion contracture could be reduced significantly from 18° (SD ± 12) to 6° (SD ± 5; p < 0.001) post-operatively. CONCLUSION: Total knee arthroplasty in haemophilic patients is associated with high revision, loosening and infection rates after 18 years. However, if revision can be avoided, joint replacement in haemophilic patients helps to relieve pain, achieve higher subjective satisfaction and to restore knee function. Level of evidence IV.

Conventional Versus Computer-Assisted Corrective Osteotomy of the Forearm: a Retrospective Analysis of 56 Consecutive Cases.

PURPOSE: Accuracy and feasibility of corrective osteotomies using 3-dimensional planning tools and patient-specific instrumentation has been reported by multiple authors with promising results. However, studies describing clinical outcomes following these procedures are rare. Therefore, the purpose of this study was to compare the results of computer-assisted corrective osteotomies of the diaphyseal and distal radius with a conventional non-computer-assisted technique regarding duration of surgery, consolidation of the osteotomy, and complications. Also, subjective and objective clinical outcome parameters were assessed. METHODS: We retrospectively compared the results of 31 patients who underwent a corrective osteotomy performed conventionally with 25 patients treated with a computer-assisted method (CA) using patient-specific instrumentation. Baseline data were similar among both groups. The duration of surgery, bony consolidation, complications, gain in range of motion, and subjective outcome were recorded. RESULTS: The mean operating time was significantly shorter in the CA group compared with the conventional group. After 12 weeks, significantly more osteotomies were considered healed in the CA group compared with the conventional group. Two patients in the CA group required revision surgery to treat nonunion of the osteotomy. Otherwise clinical results were similar among both groups. CONCLUSIONS: The results demonstrate that the computer-assisted method facilitates shorter operation times while providing similar clinical results. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Influence of disruption of the acromioclavicular and coracoclavicular ligaments on glenohumeral motion: a kinematic evaluation.

BACKGROUND: Changes to the integrity of the acromioclavicular (AC) joint impact scapulothoracic and clavicular kinematics. AC ligaments provide anterior-posterior stability, while the coracoclavicular (CC) ligaments provide superior-inferior stability and a restraint to scapular internal rotation. The purpose of this cadaveric study was to describe the effect of sequential AC and CC sectioning on glenohumeral (GH) kinematics during abduction (ABD) of the arm. We hypothesized that complete AC ligament insult would result in altered GH translation in the anterior-posterior plane during abduction, while subsequent sectioning of both CC ligaments would result in an increasing inferior shift in GH translation. METHODS: Six cadaveric shoulders were studied to evaluate the impact of sequential sectioning of AC and CC ligaments on GH kinematics throughout an abduction motion in the coronal plane. Following an examination of the baseline, uninjured kinematics, the AC ligaments were then sectioned sequentially: (1) Anterior, (2) Inferior, (3) Posterior, and (4) Superior. Continued sectioning of CC ligamentous structures followed: the (5) trapezoid and then the (6) conoid ligaments. For each group, the GH translation and the area under the curve (AUC) were measured during abduction using an intact cadaveric shoulder. Total translation was calculated for each condition between ABD 30° and ABD 150° using the distance formula, and a univariate analysis was used to compare total translation for each axis during the different conditions. RESULTS: GH kinematics were not altered following sequential resection of the AC ligaments. Disruption of the trapezoid resulted in significant anterior and lateral displacement of the center of GH rotation. Sectioning the conoid ligament further increased the inferior shift in GH displacement. CONCLUSION: A combined injury of the AC and CC ligaments significantly alters GH kinematics during abduction. Type III AC separations, result in a significant change in the shoulder's motion and may warrant surgical reconstruction to restore normal function.

The effect of the rotator interval on glenohumeral kinematics during abduction.

BACKGROUND: The rotator interval (RI) has been exploited as a potentially benign point of entry into the glenohumeral (GH) joint. Bounded by the supraspinatus, subscapularis and coracoid process of the scapula, the RI is believed to be important in the shoulder's soft tissue balancing and function. However, the role of the RI in shoulder kinematics is not fully understood. The purpose of this study is to describe the effect of the RI on GH motion during abduction of the arm. METHODS: Six shoulders from three cadaveric torsos were studied to assess the impact of changes in the RI during abduction under four conditions: Intact (Baseline), Opened, Repaired (repaired with side-to-side tissue approximation, no overlap) and Tightened (repaired with 1 cm overlap). For each group, the GH translation and area under the Curve (AUC) were measured during abduction using an intact cadaveric shoulder (intact torso). RESULTS: GH kinematics varied in response to each intervention and throughout the entire abduction arc. Opening the RI caused a significant change in GH translation. The Repair and Tightened groups behaved similarly along all axes of GH motion. CONCLUSIONS: The RI is central to normal GH kinematics. Any insult to the tissue's integrity alters the shoulder's motion throughout abduction. In this model, closing the RI side-to-side has the same effect as tightening the RI. Since suture closure may offer the same benefit as tightening the RI, clinicians should consider this effect when treating patients with shoulder laxity. This investigation provides an improved perspective on the role of the RI on GH kinematics during abduction. When managing shoulder pathology, surgeons should consider how these different methods of RI closure affect the joint's motion. In different circumstances, the surgical approach to the RI can be tailored to address each patient's specific needs.

Validation of a virtual reality-based simulator for shoulder arthroscopy.

PURPOSE: This study was to determine face and construct validity of a new virtual reality-based shoulder arthroscopy simulator which uses passive haptic feedback. METHODS: Fifty-one participants including 25 novices (<20 shoulder arthroscopies) and 26 experts (>100 shoulder arthroscopies) completed two tests: for assessment of face validity, a questionnaire was filled out concerning quality of simulated reality and training potential using a 7-point Likert scale (range 1-7). Construct validity was tested by comparing simulator metrics (operation time in seconds, camera and grasper pathway in centimetre and grasper openings) between novices and experts test results. RESULTS: Overall simulated reality was rated high with a median value of 5.5 (range 2.8-7) points. Training capacity scored a median value of 5.8 (range 3-7) points. Experts were significantly faster in the diagnostic test with a median of 91 (range 37-208) s than novices with 1177 (range 81-383) s (p < 0.0001) and in the therapeutic test 102 (range 58-283) s versus 229 (range 114-399) s (p < 0.0001). Similar results were seen in the other metric values except in the camera pathway in the therapeutic test. CONCLUSION: The tested simulator achieved high scores in terms of realism and training capability. It reliably discriminated between novices and experts. Further improvements of the simulator, especially in the field of therapeutic arthroscopy, might improve its value as training and assessment tool for shoulder arthroscopy skills. LEVEL OF EVIDENCE: II.

Does periacetabular osteotomy have depth-related effects on the articular cartilage of the hip?

BACKGROUND: Osteoarthritis may result from abnormal mechanics leading to biochemically mediated degradation of cartilage. In a dysplastic hip, the periacetabular osteotomy (PAO) is designed to normalize the mechanics and our initial analysis suggests that it may also alter the cartilage biochemical composition. Articular cartilage structure and biology vary with the depth from the articular surface including the concentration of glycosaminoglycans (GAG), which are the charge macromolecules that are rapidly turned over and are lost in early osteoarthritis. Delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC) enables noninvasive measurement of cartilage GAG content. The dGEMRIC index represents an indirect measure of GAG concentration with lower values indicating less GAG content. GAG content can normally vary with mechanical loading; however, progressive loss of GAG is associated with osteoarthritis. By looking at the changes in amounts of GAG in response to a PAO at different depths of cartilage, we may gain further insights into the types of biologic events that are occurring in the joint after a PAO. QUESTIONS/PURPOSES: We (1) measured the GAG content in the superficial and deep zones for the entire joint before and after PAO; and (2) investigated if the changes in the superficial and deep zone GAG content after PAO varied with different locations within the joint. METHODS: This prospective study included 37 hips in 37 patients (mean age 26 ± 9 years) who were treated with periacetabular osteotomy for symptomatic acetabular dysplasia and had preoperative and 1-year follow up dGEMRIC scans. Twenty-eight of the 37 also had 2-year scans. Patients were eligible if they had symptomatic acetabular dysplasia with lateral center-edge angle < 20° and no or minimal osteoarthritis. The change in dGEMRIC after surgery was assessed in the superficial and deep cartilage zones at five acetabular radial planes. RESULTS: The mean ± SD dGEMRIC index in the superficial zone fell from 480 ± 137 msec preoperatively to 409 ± 119 msec at Year 1 (95% confidence interval [CI], -87 to -54; p < 0.001) and recovered to 451 ± 115 msec at Year 2 (95% CI, 34-65; p < 0.001), suggesting that there is a transient event that causes the biologically sensitive superficial layer to lose GAG. In the deep acetabular cartilage zone, dGEMRIC index fell from 527 ± 148 msec preoperatively to 468 ± 143 msec at Year 1 (95% CI, -66 to -30; p < 0.001) and recovered to 494 ± 125 msec at Year 2 (95% CI, 5-32; p = 0.008). When each acetabular radial plane was looked at separately, the change from before surgery to 1 year after was confined to zones around the superior part of the joint. The only significant change from 1 to 2 years was an increase in the superficial layer of the superior zone (1 year 374 ± 123 msec, 2 year 453 ± 117 msec, p < 0.006). CONCLUSIONS: This study suggests that PAO may alter the GAG content of the articular cartilage with a greater effect on the superficial zone compared with the deeper acetabular cartilage zone, especially at the superior aspect of the joint. Some surgeons have observed that surgery itself can be a stressor that can accelerate joint degeneration. Perhaps the decrease in dGEMRIC index seen in the superficial layer may be a catabolic response to postsurgical inflammation given that some recovery was seen at 2 years. The decrease in dGEMRIC index in the deep layer seen mainly near the superior part of the joint is persistent and may represent a response of articular cartilage to normalization of increased mechanical load seen in this region after osteotomy, which may be a normal response to alteration in loading. CLINICAL RELEVANCE: This study looks at the biochemical changes in the articular cartilage before and after a PAO for dysplastic hips using MRI in a similar manner to using histological methods to study alterations in articular cartilage with mechanical loading. Although PAO alters alignment and orientation of the acetabulum, its effects on cartilage biology are not clear. dGEMRIC provides a noninvasive method of assessing these effects.

How do acetabular version and femoral head coverage change with skeletal maturity?

BACKGROUND: Normal changes in acetabular version over the course of skeletal development have not been well characterized. Knowledge of normal version development is important because acetabular retroversion has been implicated in several pathologic hip processes. QUESTIONS/PURPOSES: The purpose of this study was to characterize the orientation of the acetabulum by measuring (1) acetabular version and (2) acetabular sector angles in pediatric patients during development. We also sought to determine whether these parameters vary by sex in the developing child. METHODS: We evaluated CT images of 200 hips in 100 asymptomatic pediatric patients (45 boys, 55 girls; mean age, 13.5 years; range, 9-18 years) stratified by the status of the triradiate physis and sex. We determined the acetabular anteversion angle at various levels in the axial plane as well as acetabular sector angles at five radial planes around the acetabulum. RESULTS: For both genders, anteversion angle was greater for the closed physis group throughout all levels (p < 0.001) and both open and closed physis groups were more anteverted as the cut moved caudally away from the acetabular roof (p < 0.001). At the center of the femoral head, the mean anteversion angle (± SD) in girls was 15° ± 3° in the open group and 19° ± 5° in the closed group (p < 0.001). In boys, the mean anteversion angle increased from 14° ± 4° in the open group to 19° ± 4° in the closed group (p = 0.003). In the superior, posterosuperior, and posterior planes, the acetabular sector angles were greater in the closed compared with the open physis group for both boys and girls with the largest increase occurring in the male posterosuperior plane (approximately 20°) (all p < 0.05). CONCLUSIONS: This study demonstrates that acetabular anteversion and acetabular sector angles in both male and female subjects increase with skeletal maturity as a result of growth of the posterior wall. This suggests that radiographic appearance of acetabular retroversion may not be attributable to overgrowth of the anterior wall but rather insufficient growth of the posterior wall, which has clinical treatment implications for pincer-type impingement.

Three-dimensional corrective osteotomies of mal-united clavicles--is the contralateral anatomy a reliable template for reconstruction?

In computer-assisted preoperative planning of corrective osteotomies, the unaffected contralateral bone often serves as three-dimensional template for the reconstruction of mal-united bones. Before applying this approach to new anatomy such as the clavicle bone, it is important to study asymmetry between the sides. The purpose of this study was to investigate bilateral symmetry of the clavicle in healthy cadavers using three-dimensional measurement techniques. Bilateral symmetry of 102 clavicles (51 cadavers, mean age: 52.19 years, 37 male) was measured based on three-dimensional models reconstructed from computed tomography. Besides length, volume, and surface, the side-differences were evaluated by considering the mirrored left clavicle as the reconstruction template and the right clavicle as the one that will be realigned by osteotomy. The relative transformation between the aligned segments was measured to express the difference with to three-dimensional translation and rotation. The same procedure was repeated using mean-sized clavicles, one for each gender, as the template. The contralateral side was a significant more accurate reconstruction template compared to a mean-sized clavicle (P < 0.001). Nevertheless, an average side-differences with respect to rotation and translation of 8.79° ± 5.2° and 3.5 mm ± 2.7 mm, respectively. The left clavicles were significant (P = 0.001) longer with 154 mm compared to the right ones (151 mm). Three-dimensional differences between the left and right clavicles exist, but can be considered as small. Therefore, the contralateral side appears to be a reliable reconstruction template, in particular compared to a mean-sized clavicle.

Is acetabular osteoplasty always required in mixed impingement?

BACKGROUND: Mixed femoroacetabular impingement (FAI) is typically managed with both femoral and acetabular rim osteoplasties, but it has not been reported if the rim osteoplasty is always required. HYPOTHESIS/PURPOSE: We hypothesized that mixed FAI managed by femoral or combined femoral and acetabular osteoplasties will both attain satisfactory clinical results, provided intraoperative impingement-free functional motion is attained. METHODS: We retrospectively reviewed 30 hips (23 patients, mean age at surgery 24.3 years, mean follow-up time 1.6 years) with mixed FAI who underwent surgical dislocation of the hip and had femoral osteochondroplasty with rim trim (RT, n = 21) or no rim trim (NRT, n = 9). Physical examination results and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) scores were evaluated. RESULTS: Mean (± SD) WOMAC pain scores improved from 6.56 (± 2.96) to 2.33 (± 3.64) in the NRT group (p = .002) and from 6.86 (± 4.15) to 3.86 (± 3.95) in the RT group (p = .014). Function improved in both groups, but the difference was significant only for the NRT group (p < .001). Over 50 % of patients in both groups had resolution of impingement sign. Internal rotation increased from 8.6° (± 11.8) to 20.0° (± 10.4) in the NRT group (p = .043) and from 4.0° (± 12.1) to 18.6° (± 14.0) in the RT group (p < .001). Both groups had increased flexion post-operatively to normal range, but the change was only significant for the RT group (p = .02). Both groups had insignificant decreases in external rotation. CONCLUSION: Satisfactory clinical outcomes were seen in hips with mixed impingement, regardless of whether RT was performed, provided impingement-free functional motion was attained and no severe cartilage damage was seen.

Can radiographic morphometric parameters for the hip be assessed on MRI?

BACKGROUND: Although morphometric hip parameters measured on radiographs are valuable tools guiding diagnosis and therapy in patients with hip disorders, some clinicians use MRI for such measurements, although it is unclear whether the parameters assessed on MRI differ from those assessed on radiographs. QUESTIONS/PURPOSES: We asked whether the lateral center-edge angle (LCE), Tönnis angle, extrusion index, and anterior center-edge angle (ACE) are similar on MRI and radiography. METHODS: We retrospectively reviewed the imaging data of 103 hips from 103 patients: 46 with femoroacetabular impingement and 57 with hip dysplasia. We manually measured the LCE, Tönnis angle, extrusion index, and ACE from radiographs and MRI in all 103 hips. Four straight coronal (Ant-10 mm, Ant-5 mm, Center, and Post-5 mm), three straight sagittal (S-Med-5 mm, S-Center, S-Lat-5 mm), and three 25º oblique sagittal (OS-Med-5 mm, OS-Center, OS-Lat-5 mm) reformats were reconstructed from a three-dimensional isotropic morphologic MRI sequence. MRI measurements were compared against the gold standard radiographic measurements. RESULTS: We found good agreement for the LCE angle, Tönnis angle, and extrusion index between radiographic and coronal slice MRI measurements. The mean differences between radiographic and MRI measurements were 5º or less or 5% or less (for the extrusion index) in all coronal MRI slices. However, the differences between ACE angles on sagittal MRI slices and radiographs ranged from 5° to 28º. CONCLUSIONS: LCE, Tönnis angle, and extrusion index can be measured on MRI with comparable results to radiography. The ACE angle on radiographs cannot be estimated reliably from MRI. CLINICAL RELEVANCE: MRI provides similar morphometric measurements as radiography for most hip parameters, except for the ACE angle.

Is the damage of cartilage a global or localized phenomenon in hip dysplasia, measured by dGEMRIC?

BACKGROUND: The mechanism of damage in osteoarthritis is believed to be multifactorial where mechanical and biological factors are important in its initiation and progression. Hip dysplasia is a classic model of increased mechanical loading on cartilage attributable to insufficient acetabular coverage that leads to osteoarthritis. If the damage is all attributable to direct mechanical damage then one initially would expect only local, not global changes. QUESTIONS/PURPOSES: We hypothesize that in hip dysplasia although the elevated cumulative contact stresses are localized, the damage to cartilage is biologically mediated, therefore, biochemical changes will be global. METHODS: Thirty-two patients with symptomatic hip dysplasia were scanned using a 1.5-T MRI scanner. We used a high-resolution three-dimensional dGEMRIC technique to characterize the distribution of cartilage damage in dysplastic hips. High-resolution isotropic acquisition was reformatted around the femoral neck axis and the dGEMRIC index was calculated separately for femoral and acetabular cartilages. Joint space widths also were evaluated in each reformatted slice. Each hip was characterized by the presence or absence of joint migration and by Tönnis grade. RESULTS: The global dGEMRIC index correlated with the dGEMRIC indices of individual regions with the highest correlations occurring in the anterosuperior to posterosuperior regions. The corresponding correlations for joint space width were uniformly lower, suggesting that tissue loss is a more local phenomenon. Higher Tönnis grades and hips with joint migration were associated with lower dGEMRIC indices. CONCLUSIONS: The dGEMRIC index shows a global decrease, whereas tissue loss is more localized. This suggests that hip osteoarthritis in acetabular dysplasia is a biologically mediated event that affects the entire joint.

Guided growth with tension band plate or definitive epiphysiodesis for treatment of limb length discrepancy?

BACKGROUND: It is not exactly known whether guided growth or definitive epiphysiodesis techniques are superior in treating limb length discrepancy (LLD). The purpose of the present study was therefore to find out if definitive epiphysiodesis is associated with more powerful LLD correction than tension band plate epiphysiodesis. METHODS: Pediatric patients with LLD treated either with tension band plating as a guided growth technique (temporary epiphysiodesis) or a percutaneous drilling technique (definitive epiphysiodesis) around the knee and a minimum follow-up of 12 months were included in this retrospective study. Radiographic measurements were performed by two independent reviewers. The reduction in side difference between preoperative radiographs and last follow-up was calculated and compared between surgical techniques. RESULTS: Thirty-eight patients (mean age 13.6 years) were included, 17 treated with temporary and 21 with definitive epiphysiodesis. Average follow-up was at 578 days. The reduction of the LLD in 12 months was 5.7 mm in patients treated with temporary epiphysiodesis and 8.4 mm with definitive epiphysiodesis, respectively (p = 0.22). In both groups, LLD could be statistically significantly reduced after 12 and 24 months. Definitive epiphysiodesis had a lower revision rate (4.8% vs. 17.6%). Intra- and interobserver reliability of the measurements was excellent. CONCLUSIONS: As in earlier studies supposed, temporary epiphysiodesis with tension band plating seems to correct LLD less powerful compared to definitive percutaneous epiphysiodesis. However, in the present study, the differences of LLD correction were not statistically significant. We do not recommend the use of tension band plates for LLD correction due to inferior correction with higher complication and revision rate.

Correlation of Systemic Inflammatory Markers With Radiographic Stages of Charcot Osteoarthropathy.

BACKGROUND: Charcot osteoarthropathy (COA) is characterized by a progressive destruction of bone and joint associated with neuropathy and is most common in the foot and ankle. Clinical manifestation of COA is frequently indistinguishable from other causes of pain, swelling, and erythema of the affected extremity, in particular, infection. Diagnosis of COA can be challenging in particular in early stages where radiographic changes are sparse. The presence of elevated systemic inflammatory parameters in the context of suspected infection may delay early diagnosis and treatment of COA. The aim of this retrospective analysis was to assess whether elevated systemic inflammatory parameters may be present, in particular in early stages of COA and thus not be used as an exclusion criterion for the diagnosis of COA. METHODS: Forty-two patients (mean age 48.2 ± 9.4 years, 36 male, 6 female) with a diagnosis of unilateral COA were the subject of this retrospective study. The diagnosis of COA was confirmed by plain radiographs, magnetic resonance imaging and clinical course. Systemic inflammatory parameters were recorded at the time of referral. Acute stages (stages 0 and 1) were treated with a total contact cast (TCC) and protected weight bearing for a minimum of 6 weeks. For chronic stages (stages 2 and 3) custom-made shoes were prescribed. The feet were stratified into "acute" (Eichenholz stages 0 and 1) and "subacute/chronic" (Eichenholz stages 2 and 3) groups. RESULTS: Statistically significant differences were observed for all recorded systemic inflammatory parameters (C-reactive protein level, WBC count, erythrocyte sedimentation rate) between the acute and subacute/chronic groups. No statistical difference was observed considering the anatomic pattern of involvement. CONCLUSION: The present study demonstrated that elevated systemic inflammatory parameters may be present in COA and can further be used to distinguish between acute and subacute stages of COA, based on the Eichenholtz classification. Thus, we suggest that elevated inflammatory markers should not be considered an exclusion criterion for the diagnosis of COA. LEVEL OF EVIDENCE: Level III, retrospective comparative series.

Prognostic factors for mid-term symptom relief after open surgical correction for femoroacetabular impingement.

BACKGROUND: We sought to identify, which patient and radiographic factors at preoperative and 1-year follow up will predict patient symptom relief at mid-term. MATERIALS AND METHODS: A total of 50 hips in 47 patients with symptomatic FAI were included in this retrospective study. We stratified the hips into "success" and "failure" groups based on the change from baseline to mid-term follow up WOMAC pain score (mean follow up of 5.8 years). An attempt was made to identify factors that are predictive of mid-term outcome among preoperative radiographic measures, dGEMRIC index, range of motion and WOMAC score as well as 1-year follow-up range of motion, radiographic measures, and WOMAC pain scores. RESULTS: At 1-year follow up, the success rate was 72% (36/50) and at mid-term follow the success rate increased to 82% (41/50). There were no significant associations between mid-term pain scores and baseline factors (all p-values ≥0.10). One-year pain score and hip internal rotation was associated with poor mid-term pain scores but only the 1-year pain score was associated with the mid-term success/failure outcome. CONCLUSIONS: We did not identify clear preoperative predictors of mid-term results but patients with poor pain scores and limited hip internal rotation at 1-year follow-up are less likely to do well at mid-term.

Does periacetabular osteotomy for hip dysplasia modulate cartilage biochemistry?

BACKGROUND: The aim of periacetabular osteotomy is to improve joint mechanics in patients with developmental dysplasia of the hip. In our study, we tried to determine whether the proteoglycan content, as measured with delayed gadolinium-enhanced magnetic resonance imaging of cartilage (dGEMRIC), can be modulated with the alteration of the hip joint biomechanics. METHODS: In this prospective cohort study, thirty-seven patients (thirty-seven hips) with no or minimal osteoarthritis were treated with periacetabular osteotomy for symptomatic acetabular dysplasia. All patients had preoperative and one-year follow-up dGEMRIC scans. Twenty-eight of the thirty-seven also had two-year scans. The changes in dGEMRIC findings and hip morphology between the preoperative visit and the examinations at one and two years following the periacetabular osteotomy were assessed. RESULTS: The mean preoperative dGEMRIC index (and standard deviation) was 561.6 ± 117.6 ms; this decreased to 515.2 ± 118.4 ms at one year after periacetabular osteotomy but subsequently recovered to 529.2 ± 99.1 ms at two years postoperatively. The decrease in the dGEMRIC index of the acetabular cartilage after surgery appears to be most pronounced at the superior aspect of the acetabulum, where the decrease in mechanical loading after periacetabular osteotomy would be most pronounced. All domains of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) demonstrated significant improvement from the preoperative to the postoperative visits (all p < 0.001). CONCLUSIONS: Periacetabular osteotomy for developmental dysplasia of the hip appears to alter the mechanical loading of articular cartilage in the hip, which in turn alters the cartilage matrix composition, as demonstrated by dGEMRIC.