Stress Shielding around Press-Fit Radial Head Arthroplasty: Proposal for a New Classification System Based on the Analysis of 97 Patients with a Mid-Term Follow-Up and a Review of the Literature.

Stress shielding (SS) around press-fit radial head arthroplasty (RHA) was recently reported as a cause of a new type of proximal radial neck resorption (PRNR). Very few studies have analyzed this phenomenon. No comprehensive classification is currently available. We thus decided to clinically and radiographically analyze 97 patients who underwent a press-fit RHA and who were followed up for a mean period of 72 months (range: 2-14 years). PRNR in the four quadrants of the radial neck was assessed. We designed a novel SS classification based on (1) the degree of resorption of the length of the radial neck and (2) the number of neck quadrants involved on the axial plane. The mean PRNR (mPRNR) was calculated as the mean resorption in the four quadrants. mPRNR was classified as mild (<3 mm), moderate (3 to 6 mm), and severe (>6 mm). Eighty-four percent of the patients presented PRNR. mPRNR was mild in 33% of the patients, moderate in 54%, and severe in 13%. In total, 6% of the patients with mild mPRNR displayed resorption in one quadrant, 18% displayed resorption in two quadrants, 4% displayed resorption in three quadrants, and 72% displayed resorption in four quadrants. All four quadrants were always involved in moderate or severe mPRNR, with no significant differences being detected between quadrants (p = 0.568). mPRNR has no apparent effect on the clinical results, complications, or RHA survival in the medium term. However, longer-term studies are needed to determine the effects of varying degrees of PRNR on implant failure.

Myocarditis and pericarditis in individuals exposed to the Ad26.COV2.S, BNT162b2 mRNA, or mRNA-1273 SARS-CoV-2 vaccines.

Importance: There is a high level of public and professional interest related to potential safety issues of the COVID-19 vaccines; however, no serious adverse cardiovascular events were reported in phase 3 randomized controlled trials of their safety and efficacy. Moreover, none of the case series from the United States (US) of these potential complications have been population-based. Objectives: To estimate the reporting rates of myocarditis and pericarditis in the US using the Vaccine Adverse Event Reporting System (VAERS), and to assess if these adverse events were disproportionally reported among the different COVID-19 vaccines. Design setting and participants: All cases of myocarditis and pericarditis from VAERS reported up to July 28, 2021. Exposure: Single-dose Ad26.COV2.S, BNT162b2 mRNA, or mRNA-1273 SARS-CoV-2 vaccinations. Main outcomes and measures: Reporting rates were computed by dividing the total number of cases of myocarditis and pericarditis (combined) by the total number of vaccine doses administered. Disproportionality analyses were performed to evaluate disproportional reporting of myocarditis and pericarditis for the Ad26.COV2.S and mRNA-1273 vaccines vs. the BNT162b2 mRNA vaccine. Results: By July 28, 2021, 1392, 699, and 68 cases of myocarditis or pericarditis had been reported out of 1.91, 1.38, and 1.33 million administered doses of the BNT162b2 mRNA, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines, respectively. Median times to event were 3 days, 3 days, and 9 days for the BNT162b2 mRNA, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines. The reporting rates for myocarditis or pericarditis were 0.00073 (95% confidence interval, 95% CI 0.00069-0.00077), 0.00051 (95% CI 0.00047-0.00055), and 0.00005 events per dose (95% CI 0.00004-0.00006) for the BNT162b2 mRNA, mRNA-1273, and Ad26.COV2.S COVID-19 vaccines, respectively. Myocarditis and pericarditis were disproportionally reported following the BNT162b2 mRNA vaccine when compared with the other vaccines, using both disproportionality measures. Conclusions and relevance: We found reporting rates of myocarditis and pericarditis to be less than 0.1% after COVID-19 vaccination. Rates were highest for the BNT162b2 mRNA vaccine, followed by the mRNA-1273 and Ad26.COV2.S, respectively. However, the reporting rates of myocarditis and pericarditis secondary to vaccination remains less common than those seen for SARS-CoV-2 infection.

Assessment of progression and clinical relevance of stress-shielding around press-fit radial head arthroplasty.

Aims: The aim of this study was to analyze how proximal radial neck resorption (PRNR) starts and progresses radiologically in two types of press-fit radial head arthroplasties (RHAs), and to investigate its clinical relevance. Methods: A total of 97 patients with RHA were analyzed: 56 received a bipolar RHA (Group 1) while 41 received an anatomical implant (Group 2). Radiographs were performed postoperatively and after three, six, nine, and 12 weeks, six, nine, 12, 18, and 24 months, and annually thereafter. PRNR was measured in all radiographs in the four radial neck quadrants. The Mayo Elbow Performance Score (MEPS), the abbreviated version of the Disabilities of the Arm, Shoulder, and Hand questionnaire (QuickDASH), and the patient-assessed American Shoulder and Elbow Surgeons score - Elbow (pASES-E) were used for the clinical assessment. Radiological signs of implant loosening were investigated. Results: The mean follow-up was six years (2 to 14). PRNR started after a mean of 7.5 weeks (SD 2.1) and progressed significantly during the first two years, by the end of which the bone resorption stabilized. PRNR was detected in 81% (n = 45) of patients in Group 1 and 88% (n = 36) in Group 2. The final mean PRNR was 3.0 mm (SD 2.3) in Group 1 and 3.7 mm (SD 2.5) in Group 2. The mean MEPS, QuickDASH, and pASES-E were 95.9 (SD 11.5), 4.4 (SD 9.2), and 94.8 (SD 10.9) in Group 1 and 92.2 (SD 16.2), 9.9 (SD 21.5), and 90.8 (SD 15) in Group 2, respectively. No significant differences were observed between groups in the clinical and radiological outcomes. No correlations were found between PRNR and the clinical results. Conclusion: PRNR after press-fit RHA is a common radiological finding that develops in the first 24 months before stabilizing definitively. PRNR does not affect the clinical results or implant survival in the mid term.

Delayed Surgical Treatment of Displaced Intra-Articular Calcaneal Fractures in Major Trauma Is Safe and Effective.

BACKGROUND: To assess whether delaying operative fixation through the sinus tarsi approach resulted in a decreased wound complications rate or could hinder the quality of reduction in subjects with Sanders type II and III displaced intra-articular calcaneus fractures. METHODS: From January 2015 to December 2019, all polytrauma patients were screened for eligibility. We divided patients into two groups: Group A, treated within 21 days after injury; Group B, treated more than 21 days after injury. Wound infections were recorded. Radiographic assessment consisted of serial radiographs and CT scans: postoperatively (T0) and at 12 weeks (T1) and at 12 months after surgery (T2). The quality of reduction of the posterior subtalar joint facet and calcaneal cuboid joint (CCJ) was classified as anatomical and non-anatomical. A post hoc power calculation was performed. RESULTS: A total of 54 subjects were enrolled. Four wound complications (three superficial, one deep) were identified in Group A; two wound complications (one superficial one deep) were identified in Group B. According to "mean interval between trauma and surgery" and "duration of intervention", there was a significant difference between the groups (p < 0.001). There were no significant differences between Groups A and B in terms of wound complications or quality of reduction. CONCLUSIONS: The sinus tarsi approach is a valuable approach for the surgical treatment of closed displaced intra-articular calcaneus fractures in major trauma patients who need delayed surgery. The timing of surgery did not negatively influence the quality of the reduction and the wound complication rate. LEVEL OF EVIDENCE: level II, prospective comparative study.

Morphometric analysis of the lateral column of the distal humerus with an interest on radio-capitellar arthroplasty design. A computed tomography anatomical study on 50 elbows.

PURPOSE: To perform a morphometric analysis of the distal humerus lateral column medullary canal (LCMC). METHODS: Fifty computed tomography(CTs) from 24 males and 26 females were examined. Two observers measured: (1) the capitellum sagittal (RS) and axial (RT) radii of curvature; (2) the sagittal(Sd) and coronal(Cd) diameters of the LCMC in 5 different disto-proximal sites spaced 4 mm apart; (3) the capitellum and LCMC axis offsets on the sagittal (capSO,axSO) and coronal (capCO,axCO) planes; (4) the sagittal (Si) and coronal (Ci) inclination of the LCMC axis. RESULTS: The mean RS and RT were 1.07 cm (SD, 0.11) and 1.30 cm (SD, 0.11), respectively. The mean Sd and Cd values were 1.17 cm (SD, 0.17) and 1.58 cm (SD, 0.24), respectively, with a disto-proximal decrease on both planes. The capSO, capCO, axSO and axCO mean values were 0.76 (SD, 0.21), 1.60 (SD, 0.27), - 0.16 (SD, 0.30) and 0.79 cm (SD, 0.30), respectively. Si and Ci were 70° and 72°, respectively. A strong correlation (r = 0.78) was found between RS and RT and between adjacent levels of Sd and Cd. AxSO and axCO yielded a strong inverse correlation. Male patients showed higher values than female ones in all variables (p < 0.03). The intra-class correlation coefficient (ICC) was always > 0.9. CONCLUSION: The dimensions of the LCMC decrease disto-proximally, with the coronal diameters being greater than the sagittal diameters, resembling a portion of an elliptic torus with an antero-medial concavity. The articular surface of the humeral capitellum is non-spherical, with two strongly correlated radii of curvature. The results of this study may be relevant to the stem design of radiocapitellar arthroplasty.

Suprapatellar intramedullary nailing of tibial shaft fractures in pregnancy. A report of two cases.

BACKGROUND: Treatment of closed tibial shaft fractures in the 3rd trimester of pregnancy is controversial. Since there are few case reports published in literature, there is no consensus on the appropriate management of these fractures. This case report proposes intramedullary nailing throught the suprapatellar approach for the treatment of tibial shaft fracture in pregnant women, never described before in literature. CASE PRESENTATION: We report 2 cases of a tibial diaphyseal fracture treated by intramedullary nailing in women at the 3rd trimester of pregnancy. CONCLUSION: Surgical treatment of tibial shaft fracture of pregnant women in the 3rd trimester of pregnancy with intramedullary nailing seems to be safe. The use of the specific suprapatellar approach helps in the intra-operative management of the pregnant patients.

Epidemiology of isolated olecranon fractures: a detailed survey on a large sample of patients in a suburban area.

BACKGROUND: Literature lacks data concerning several epidemiologic aspects of isolated olecranon fractures (IOFs). The few studies that have analyzed this type of fracture show a low sample size and contradicting results. METHODS: This retrospective study included 165 consecutive patients (82 men and 83 women) who sustained an IOF in the past 10 years. Participants who were aged <16 years or had a previous elbow fracture or had a fracture that involved other bones of the elbow joint were excluded. Data regarding age, sex, season, date, and fracture side were collected. As per the mechanism of injury, we arbitrarily distinguished 7 subgroups. IOFs were classified as per the Mayo and AO classifications using x-ray. Statistics were performed. RESULTS: The patients' mean age was 58.5 (standard deviation [SD], 21.3) years, and men and women were aged 48.1 (SD, 19.8) years and 67.9 (SD, 18.8) years, respectively. The most frequent fracture patterns were the MAYO 2A and the AO 2U1B1(d). Low-energy mechanisms caused simple dislocated-stable fractures, whereas high-energy mechanisms caused both simple and comminuted displaced-stable fractures. Significant differences in the trauma mechanism were found between male and female patients. The former fractures showed a bimodal distribution depending on the patients' age group, whereas in women, the traumatic event was mainly represented by a low-energy mechanism. Overall, the most common cause of fracture was a low-energy accident. The seasonal distribution of fractures was different for male and female patients being more frequent in summer among young men and more frequent in winter among the elderly, both men and women. The left side was involved in 87 patients. CONCLUSION: IOFs occur equally in both genders, although with different age distribution. The most common fracture pattern was a simple displaced-stable fracture (MAYO 2A and AO 2U1B1[d]). Young men are more often subject to high-energy injuries that occur in road accidents, whereas with aging, they become more prone to fragility fractures as women. Female patients are usually older and are mostly affected by low-energy traumas as a fall from a standing height.

Distal biceps tendon repair and posterior interosseous nerve injury: clinical results and a systematic review of the literature.

Aim To report clinical, functional and radiographic results of oneincision distal biceps tendon repair with Toggle Loc (Zimmer-Biomet, Warsaw, Indiana, USA) at an average 4-year follow-up and to assess posterior interosseous nerve injury complications after reconstruction. Methods We conducted a retrospective review of 58 consecutive distal biceps tendon repairs performed at our department between 2010 and 2018. Disabilities of Arm, Shoulder and Hand (DASH) score, Visual Analogue Scale (VAS) scale and elbow range of motion (ROM) were recorded at each follow-up and an ultrasound examination was also performed to assess the repaired biceps brachii tendon. Results Clinical evaluation showed good and excellent results at medium- and long-term follow-up. A temporary posterior interosseous nerve (PIN) palsy developed in four (6.81%) patients and always resolved in 8 weeks. PIN palsy prevalence is in accordance with the results of the previous studies. Conclusion Distal biceps tendon repair with Toggle Loc is an effective surgical procedure. PIN injury is a relatively rare complication after one-incision anterior repair. Our complication rate did not differ significantly from other studies that have used cortical button fixation, reported in current literature. Our results confirm that accidental injury of PIN may also happen to experienced surgeons and suggest extreme care and an appropriate surgical technique to reduce this iatrogenic risk.

Chronic complex persistent elbow instability: a consecutive and prospective case series and review of recent literature.

BACKGROUND: Chronic complex persistent elbow instability (CCPEI) is a condition that even expert elbow surgeons find challenging to treat. The results of the few studies that have dealt with the treatment of this condition are conflicting. We describe the surgical results of a consecutive prospective series of patients with CCPEI and provide a review of the recent literature. METHODS: We assessed 21 patients with previous failed surgical or conservative treatment, with a terrible-triad injury in 13, Monteggia-like lesion in 6, humeral shear fracture-dislocation in 1, and radial head fracture-dislocation in 1. Overall, 21 open débridement procedures, 15 ulnar nerve transpositions, 6 ulnar in situ neurolysis procedures, 7 total elbow arthroplasties, 8 radial head arthroplasties, 1 radial head resection with humeroradial anconeus interpositional arthroplasty, 4 coronoid graft reconstructions, 14 ligament retensioning procedures, 3 ulnar nonunion treatments, and 2 ulnar osteotomies were performed. Two dynamic external fixators were applied. The Mayo Elbow Performance Score, quick Disabilities of the Arm, Shoulder and Hand score, and modified American Shoulder and Elbow Surgeons score were used preoperatively and postoperatively. RESULTS: The mean follow-up period was 29.4 months. A significant improvement was found between preoperative and postoperative clinical scores and range-of-motion values. The reintervention and major complication rates were 19% and 23%, respectively. Arthritic evolution was observed in 71% of the cases. CONCLUSIONS: CCPEI is a challenging condition with an uncertain prognosis. The variability in patients' pathoanatomic conditions requires customized surgical treatment aimed at elbow stabilizer reconstruction when the ulnohumeral joint is preserved or aimed at joint replacement in case of severe articular degeneration. The time interval between the initial trauma and index surgical procedure significantly affects the feasibility of reconstructive procedures.

PEEK radiolucent plate for distal radius fractures: multicentre clinical results at 12 months follow up.

INTRODUCTION: Open reduction and internal fixation (ORIF) with plate and screws represents the recommended treatment for unstable intra-articular distal radius fractures. Although significant progresses in surgical technique have been made, anatomical reconstruction of radio-carpal articular surface still represent a difficult task, especially in multifragmentary fractures. Available PEEK reinforced-carbon fiber composite radiolucent devices allow both an easier and more careful assessment of intra-operative reduction of the articular surface of distal radius and prompt correction of any residual step deformity. MATERIALS AND METHODS: We retrospectively reviewed clinical and radiological multicentre results of 71 consecutive AO B and C fracture pattern of distal radius treated using the same PEEK reinforced-carbon fiber composite radiolucent plate. RESULTS: Three patients lost at final follow up and 4 cases with incomplete radiological documentations were excluded from the study. 64 patients (38 females, 26 males) were available and formed the basis of this report. Fracture types included 9 patients with 23-B, 13 patients 23-B2,15 patients with 23-B3,10 patients with 23-C1, 7 patients with 23-C2 and 10 patients with 23-C3. Mean Modified Mayo wrist Score was on average 38.11 (SD 10.1; range 24-75, 95%CI 34.7-41.4), 67.22 (SD 9.6, range 50-90, 95%CI 64-70.4), 90.54 (SD 6.3, range 75-100, 95%CI 88.4-92.6) at one, two and twelve months of follow-up, respectively. A statistically significant difference was found between mean scores at different follow-up periods (p = 0.001). We noted 1 case of distal screw fixation aseptic loosening at 5 months post surgical intervention. CONCLUSIONS: PEEK reinforced-carbon fiber composite radiolucent plate represents a useful device for treatment of complex distal radius fractures in the adult population. It possesses unique biomechanical properties and allows for an easier anatomical reduction during surgical intervention.

Epidemiology of proximal humeral fractures: a detailed survey of 711 patients in a metropolitan area.

BACKGROUND: Literature lacks data concerning several epidemiologic aspects of proximal humeral fractures (PHFs). METHODS: This retrospective study included 711 consecutive patients (209 men, 502 women) who sustained a PHF in the last 3 years. Participants were divided into 2 groups, adults and children. Data regarding age, sex, date, and fracture side were collected. According to the mechanism of injury, we arbitrarily distinguished 7 subgroups. PHFs were classified according to the head-greater-lesser-shaft (HGLS)-Hertel classification and to the Salter-Harris classification using x-ray and computed tomography imaging. RESULTS: PHFs represent 5.03% of the overall fractures. The right side was involved in 389 patients (54.7%; P = .6). The mean age of male and female patients was 55.4 (standard deviation, 21.9) years and 67.0 (standard deviation, 16.1) years, respectively (P = .0001). Significant differences in the trauma mechanism between female patients (street/home low-energy trauma) and male patients (high-energy trauma) were found. A significant correlation between trauma mechanisms from 1 to 5 and fracture patterns H-G-L-S, HL-G-S, HGL-S, and HLS-G was observed. The occurrence of the same patterns significantly varied according to different age subgroups. Considering the pediatric population, a significant incidence of Salter-Harris 2 in both genders was found. No correlation was observed between the fracture patterns and the trauma mechanism. CONCLUSIONS: PHFs have a higher prevalence and incidence in females and in older age, respectively; they are more frequent in the winter months. In addition, male fractures are due to different traumatic events than those in females. A correlation between trauma and PHF pattern was evident only for adults. Some fracture patterns are correlated with different ranges of age in all patients.

Morphometric anatomical and CT study of the human adult sacroiliac region.

PURPOSE: To identify and describe the morphometry and CT features of the articular and extra-articular portions of the sacroiliac region. The resulting knowledge might help to avoid complications in sacroiliac joint (SIJ) fusion. METHODS: We analyzed 102 dry hemi-sacra, 80 ilia, and 10 intact pelves and assessed the pelvic computerized tomography (CT) scans of 90 patients, who underwent the examination for conditions not involving the pelvis. We assessed both the posterior aspect of sacrum with regard to the depressions located externally to the lateral sacral crest at the level of the proximal three sacral vertebrae and the posteroinferior aspect of ilium. Coronal and axial CT scans of the SIJ of patients were obtained and the joint space was measured. RESULTS: On each side, the sacrum exhibits three bone depressions, not described in anatomic textbooks or studies, facing the medial aspect of the posteroinferior ilium, not yet described in detail. Both structures are extra-articular portions situated posteriorly to the SIJ. Coronal CT scans of patients showing the first three sacral foramens and the interval between sacrum and ilium as a continuous space display only the S1 and S3 portions of SIJ, the intermediate portion being extra-articular. The S2 portion is visible on the most anterior coronal scan. Axial scans show articular and extra-articular portions and features improperly described as anatomic variations. CONCLUSIONS: Extra-articular portions of the sacroiliac region, not yet described exhaustively, have often been confused with SIJ. Coronal CT scans through the middle part of sacrum, the most used to evaluate degenerative and inflammatory conditions of SIJ, show articular and extra-articular portions of the region.

Lumbar Interspinous Process Fixation and Fusion with Stand-Alone Interlaminar Lumbar Instrumented Fusion Implant in Patients with Degenerative Spondylolisthesis Undergoing Decompression for Spinal Stenosis.

STUDY DESIGN: Prospective cohort study. PURPOSE: To assess the ability of a stand-alone lumbar interspinous implant (interspinous/interlaminar lumbar instrumented fusion, ILIF) associated with bone grafting to promote posterior spine fusion in degenerative spondylolisthesis (DS) with vertebral instability. OVERVIEW OF LITERATURE: A few studies, using bilateral laminotomy (BL) or bilateral decompression by unilateral laminotomy (BDUL), found satisfactory results in stenotic patients with decompression alone, but others reported increased olisthesis, or subsequent need for fusion in DS with or without dynamic instability. METHODS: Twenty-five patients with Grade I DS, leg pain and chronic low back pain underwent BL or BDUL and ILIF implant. Olisthesis was 13% to 21%. Follow-up evaluations were performed at 4 to 12 months up to 25 to 44 months (mean, 34.4). Outcome measures were numerical rating scale (NRS) for back and leg pain, Oswestry disability index (ODI) and short-form 36 health survey (SF-36) of body pain and function. RESULTS: Fusion occurred in 21 patients (84%). None had increased olisthesis or instability postoperatively. Four types of fusion were identified. In Type I, the posterior part of the spinous processes were fused. In Type II, fusion extended to the base of the processes. In Type III, bone was present also around the polyetheretherketone plate of ILIF. In Type IV, even the facet joints were fused. The mean NRS score for back and leg pain decreased by 64% and 80%, respectively. The mean ODI score was decreased by 52%. SF-36 bodily pain and physical function mean scores increased by 53% and 58%, respectively. Computed tomography revealed failed fusion in four patients, all of whom still had vertebral instability postoperatively. CONCLUSIONS: Stand-alone ILIF with interspinous bone grafting promotes vertebral fusion in most patients with lumbar stenosis and unstable Grade I DS undergoing BL or BDUL.

The risk of sacrificing the PCL in cruciate retaining total knee arthroplasty and the relationship to the sagittal inclination of the tibial plateau.

BACKGROUND: In cruciate retaining total knee arthroplasty (TKA), a partial avulsion of PCL may occur when en-bloc tibial osteotomy is performed. We evaluated the effects of a tibial cut performed with different degrees of posterior slope on PCL insertion and whether the results are affected by the sagittal inclination of the patient's tibial plateau. METHODS: We selected 83 MRIs of knees showing mild or no degenerative changes. The effects of a simulated tibial cut performed with a posterior slope of 0°, 3°, 5° and parallel to the patient's tibial plateau inclination on PCL insertion in the proximal tibia were investigated. The results were correlated with the degree of posterior inclination of the tibial plateau. RESULTS: Every angle we used for the tibial cut caused a PCL avulsion greater than 50%. The percentage of PCL avulsion significantly increased with increasing the posterior slope of the tibial cut. Patients with sagittal tibial plateau inclination <5° showed greater PCL avulsion than those with sagittal inclination >8°. CONCLUSIONS: Most of the PCL insertion is likely to be sacrificed when resection of the proximal tibia is performed en-block. The risk of PCL avulsion is reduced in patients showing a marked posterior inclination of the tibial plateau, but even in this group of patients a surgical technique aimed at sparing most of the PCL insertion is necessary.

Effects of tibial torsion on distal alignment of extramedullary instrumentation in total knee arthroplasty.

BACKGROUND AND PURPOSE: Whether tibial torsion affects the positioning of extramedullary instrumentation and is a possible factor in malalignment of the tibial component in total knee arthroplasty (TKA) is unknown. We assessed the influence of tibial torsion on distal alignment of extramedullary systems for TKA, using the center of the intermalleolar distance as anatomical reference at the ankle joint. PATIENTS AND METHODS: We analyzed CT scans of knee and ankle joints of 50 patients with knee osteoarthritis (mean age 73 years, 52 legs). The tibial mechanical axis was identified and translated anteriorly at the level of the medial one-third (proximal AP axis 1), at the medial border of the tibial tuberosity (proximal AP axis 2), and at the level of the talar dome (distal AP axis). The center of the intermalleolar distance and the width of the medial and lateral malleolus were calculated. The proximal AP axes 1 and 2 were translated at the level of the ankle joint and any difference between their alignment and the distal AP axis was calculated as angular and linear values. RESULTS: The center of the ankle joint was located, on average 2 mm medial to that of the intermalleolar distance. The distal AP axis was externally rotated by 18° and 27° compared to the proximal AP axes 1 and 2, respectively. Overall, the center of the ankle joint was shifted laterally by 9-11 mm with respect to the proximal AP tibial axes. INTERPRETATION: To avoid a varus tibial cut in TKA, extramedullary alignment systems should be aligned more medially at the ankle joint than previously thought, due to the effect of tibial torsion and-to a lesser extent-to the different malleolar width.

Influence of cartilage and menisci on the sagittal slope of the tibial plateaus.

We analyzed the magnetic resonance studies of the knee in 80 subjects, 45 men and 35 women with a mean age of 38.9 years, who showed no pathological condition of the joint. Using an imaging visualization software, the sagittal longitudinal axis of the tibia was identified. The angle between this axis and a line tangent to the bone profile of the tibial plateau (bone slope) and to the superior border of the menisci (meniscal slope) were calculated. Thickness of anterior and posterior portion of menisci and underlying cartilage were also measured. The bone slope averaged 8° and 7.7° on the medial and lateral sides, respectively. The mean meniscal slope was 4.1° and 3.3° on the medial and lateral sides, respectively, with a significant difference compared with the bone slope. Menisci and underlying cartilage were significantly thicker in their posterior than their anterior portion (7.6 and 5.2 mm, respectively, in the medial compartment; 8.6 and 5.2 mm, respectively, in the lateral compartment). The presence of cartilage and menisci implies a significant decrease in the posterior tibial slope. In the lateral compartment, the greater the bone slope, the larger the difference between bone and meniscal slope, which means that a marked posterior tilt of the lateral tibial plateau is decreased by the cartilage and meniscus. These findings should be taken into account in planning surgical procedures which affect the slope of the articular tibial surface.

Combining different rotational alignment axes with navigation may reduce the need for lateral retinacular release in total knee arthroplasty.

PURPOSE: The aim of the study was to compare femoropatellar alignment and the incidence of lateral retinacular release (LRR) in total knee arthroplasty (TKA) in which the rotational alignment of the femoral component was determined using a combination of different rotational alignment axes and navigation or a single reference axis in the standard procedure. METHODS: We assessed 66 patients undergoing TKA in whom the rotation of the femoral component was determined on the posterior condylar axis in standard procedures (group A) and 65 patients in whom it was determined by combining the posterior condylar axis, anteroposterior axis and epicondylar axis in navigated procedures (group B). The mean age was 68 and 69 years in groups A and B, respectively. Patellar tracking was assessed after deflation of the tourniquet and LRR performed in the presence of maltracking. Visual analogue scale (VAS), Knee Society Score (KSS), Lonner patellar score and patellar tilt were recorded. RESULTS: LRR was carried out in 18 cases (27 %) in group A and in four (6 %) in group B (p = 0.003). The KSS and VAS were improved significantly compared to the preoperative status, but with no significant differences between the two groups. The patellar score showed a greater improvement in the navigated compared to the standard group at the four week follow-up. Patella tilt improved significantly in both groups. The complication rate was similar in the two groups. CONCLUSIONS: Combining different rotational alignment axes with navigation significantly reduces patellar maltracking and the need for LRR compared to the standard procedure in which the posterior condylar axis is used as single anatomical reference.