Influence of Skin Marker Positioning and Their Combinations on Hip Joint Center Estimation Using the Functional Method.

Accurate estimation of hip joint center (HJC) position is crucial during gait analysis. HJC is obtained with predictive or functional methods. But in the functional method, there is no consensus on where to place the skin markers and which combination to use. The objective of this study was to analyze how different combinations of skin markers affect the estimation of HJC position relative to predictive methods. Forty-one healthy volunteers were included in this study; thirteen markers were placed on the pelvis and hip of each subject's lower limbs. Various marker combinations were used to determine the HJC position based on ten calibration movement trials, captured by a motion capture system. The estimated HJC position for each combination was evaluated by focusing on the range and standard deviation of the mean norm values of HJC and the mean X, Y, Z coordinates of HJC for each limb. The combinations that produced the best estimates incorporated the markers on the pelvis and on proximal and easily identifiable muscles, with results close to predictive methods. The combination that excluded the markers on the pelvis was not robust in estimating the HJC position.

Gait analysis after total hip arthroplasty by direct minimally invasive anterolateral approach: A controlled study.

INTRODUCTION: Clinical and functional improvement after minimally invasive total hip arthroplasty (THA) has become increasingly controversial. The minimally invasive anterolateral approach (MIALA) allows rapid recovery resulting in a reduced need for rehabilitation. Alterations in muscle and static balance have previously been demonstrated. Results in the context of quantified gait analysis (QGA) and MIALA compared to an asymptomatic population remain unknown beyond one year postoperatively. Thus, the main objective of this controlled study was to compare the spatiotemporal parameters of gait, obtained using a QGA, beyond one year postoperatively in subjects operated on for THA by MIALA, with a group of asymptomatic subjects of the same age. The secondary objectives of the study were to compare the other QGA and EMG data acquired in operated subjects with asymptomatic subjects. HYPOTHESIS: We hypothesized that QGA and EMG parameters would not normalize beyond one year postoperatively. PATIENTS AND METHODS: Thirty-one subjects were recruited, including 16 patients (68 years old; IQR: 65-70) who underwent MIALA, at 15.5 months postoperatively (IQR: 13-17) and 15 asymptomatic subjects (62 years old; IQR: 61-71). Subjects underwent QGA and maximal isometric muscle force tests on the gluteus medius, gluteus maximus, Tensor Fascia Lata (TFL) and Sartorius muscles. Spatiotemporal gait parameters were the primary endpoint. The other QGA parameters: kinetics (characteristic values of vertical ground reaction forces, peak hip moments) and kinematics (hip joint amplitudes and pelvic mobility in the frontal and sagittal plane) constituted the secondary criteria. RESULTS: Five subjects were excluded for unrestored offset. Walking speed was lower in operated patients (1.03m/s versus 1.18m/s, p=0.005). Maximal isometric muscle force moments were lower in patients operated on for the gluteus maximus and medius as well as the TFL (p<0.005). The vertical ground reaction forces were lower for the operated patients for the loading phase (FzFCmax, p=0.001), the single stance phase (FzSPmin, p=5.05.10-2) and the swing phase (FzTOmax, p=0.0002). The moments were lower in the sagittal plane for the operated patients (0.6N.m for the operated versus 1.1N.m for the asymptomatic, p=0.02). The pelvic amplitudes in the sagittal plane were lower for operated patients (3.3° versus 7.2°, p=0.05). DISCUSSION: Our hypothesis appears to be validated. Gait deficits persisted beyond one year postoperatively after THA with MIALA. A decrease in walking speed, maximal isometric muscle force of the gluteus medius and gluteus maximus and TFL was observed, as well as a decrease in propulsive force and peak hip moment. Functionally, these results could signify muscle damage following surgery, requiring rehabilitation for improved muscle function. LEVEL OF PROOF: III: Non-randomized controlled trial.

MRI assessment of minimally invasive anterolateral approaches in total hip arthroplasty.

INTRODUCTION: Total hip arthroplasty (THA) on a minimally invasive anterolateral (MIAL) approach frequently leads to gluteus minimus and gluteus medius lesions, and sometimes to tensor fasciae latae (TFL) denervation. We therefore developed compensatory strategies, which we assessed on pre- and post-operative MRI: 1) to assess gluteus minimus and gluteus medius fatty infiltration (FI), 2) to assess TFL FI, and 3) to assess FI in the other periarticular muscles. HYPOTHESIS: The modified MIAL approach reduces the rate of gluteus minimus and gluteus medius lesion. MATERIALS AND METHODS: A continuous prospective single-surgeon series of THA using a MIAL approach included 25 patients. Femoral implantation was performed with the hip in extension so as to distance the proximal femur from the gluteals, avoiding muscle trauma. The superior gluteal nerve branch in the space between the gluteus medius and TFL, running toward the TFL, was systematically released and protected. MRI was performed preoperatively and at 3 months and 1 year post-surgery. FI was analyzed according to the Goutallier classification in all periarticular muscles. RESULTS: One patient lacked preoperative MRI and was excluded, leaving 24 patients, for 72 MRIs. In 10/24 patients (41.7%) the gluteus minimus and in 8/24 patients (33.3%) the anterior third of the gluteus medius showed ≥2 grade increase in FI between preoperative and 1-year MRI, with significant increases in both at 3 months (p<0.001) and 1 year (p<0.001). At least a 2 grade increase in FI at 1 year was seen in 1 patient (4.2%) in the TFL, in 2 (8.3%) in the piriformis, and in 1 (4.2%) in the obturator internus. There were no significant differences in FI between preoperative, 3-month or 1-year MRI in any other periarticular muscles. CONCLUSION: Femoral implantation in hip extension did not reduce the rate of gluteal lesions, which remained frequent. In contrast, release of the superior gluteal nerve branch could be effective in conserving TFL innervation. Some rare lesions of the proximal part of the pelvi-trochanteric muscles were also observed. LEVEL OF EVIDENCE: IV, Prospective case series.

Comparative MRI assessment of three minimally invasive approaches in total hip arthroplasty.

INTRODUCTION: Minimally invasive approaches (direct anterior approach: DAA; minimally invasive anterolateral: MIAL; piriformis-sparing posterior approach: PSPA) are widely used for total hip arthroplasty (THA), with a muscle-sparing objective. There are no published comparative studies of muscle damage secondary to these approaches. The aim of the present study was to compare fatty infiltration (FI) on MRI induced by DAA, MIAL and PSPA in THA 1) in the tensor fasciae latae (TFL) and sartorius muscles, 2) in the gluteal muscles, and 3) in the pelvitrochanteric muscles. HYPOTHESIS: Greater FI is induced by DAA in anterior muscles, by MIAL in gluteal muscles and by PSPA in pelvitrochanteric muscles. MATERIALS AND METHODS: Three continuous prospective series of THA by DAA, MIAL and PSPA included 25 patients each. MRI was performed preoperatively and at 1 year postoperatively. FI was graded on the Goutallier classification in all periarticular hip muscles. Muscles showing ≥2 grade aggravation at 1 year were considered damaged. RESULTS: Nine patients whose preoperative MRI was uninterpretable were excluded. In all, 66 patients (21 DAA, 24 MIAL and 21 PSPA) with 132 MRI scans were analyzed. TFL was damaged in 2/21 DAA patients (9.5%), 1/24 MIAL patients (4.2%) and 0/21 PSPA patients (0%). There were no sartorius lesions. The anterior third of the gluteus medius was damaged in 8/24 MIAL patients (33.3%) and the gluteus minimus in 10/24 (41.7%), compared to 1/21 DAA patients (4.8%) and 0/21 PSPA patients (0%). The mid and posterior thirds of the gluteus medius and the gluteus maximus were never damaged. The piriformis muscle was damaged in 3/21 DAA patients (14.3%), 2/24 MIAL patients (8.3%) and 2/21 PSPA patients (9.5%). The obturator internus was damaged in 4/21 DAA patients (19%), 1/24 MIAL patients (4.2%) and 16/21 PSPA patients (76.2%). The obturator externus and quadratus femoris were mainly damaged in PSPA patients: respectively, 5/21 (23.8%) and 4/21 patients (19%)). CONCLUSION: The muscle-sparing properties of minimally invasive hip approaches are only theoretical. In the present series, there were rare TFL lesions with DAA and MIAL. Gluteus medius and minimus lesions were frequent in MIAL. Pelvitrochanteric muscles lesions were more frequent in PSPA, but found in all 3 approaches. These findings should help guide surgeons in their choice of approach and in informing patients about the damage these minimally invasive approaches can cause. LEVEL OF EVIDENCE: III, prospective comparative study.

Stabilometric assessments of two rehabilitation protocols on postural parameters after posterior total hip arthroplasty: A prospective randomized comparative study.

INTRODUCTION: After total hip arthroplasty (THA), patients continue to have muscular, functional and postural deficits. The literature seems to support the use of postoperative rehabilitation, especially self-directed programs. However, there is no set protocol for the management of postural disorders. Therefore, the purpose of this study was to compare postural parameters of a group of patients who underwent posterior THA followed by 2 different types of rehabilitation (stabilometric platform (SP) and home-based self-directed protocols) with a control group of operated patients who did not undergo rehabilitation and a control group of age-matched asymptomatic subjects. HYPOTHESIS: We hypothesized that rehabilitation would normalize the stabilometric parameters. PATIENTS AND METHODS: A total of 67 subjects were enrolled in this study (mean age 67.85±1.22years) and divided into 4 groups. Forty-one of these subjects had undergone a posterior THA were randomly assigned between D10 and D21 to one of the following 3 groups: no rehabilitation control group (THACG=14), supervised rehabilitation with a stabilometric platform group (RSPG=16), and a self-directed home-based rehabilitation group (SDHRG=11). The 4th group was a control group made up of 26 age-matched asymptomatic nonoperated subjects (CG55-80). These rehabilitation protocols lasted 3weeks. At the end of the 3weeks, the groups performed the same stabilometric single leg and double leg stance tests (considering lower limb dominance) on an SP. RESULTS: No significant differences were observed between groups in the bipedal stance, except between the CG55-80 and the THACG, where a higher energy expenditure was observed in the THACG during the static stance with eyes open (EO) and eyes closed (EC): increase in the path length (Plength) covered by the center of pressure (COP) (EO: p=01; EC: p=03) and the average velocity (Vavg) of the COP (EO: p=01; EC: p=03). These differences were not observed in the SDHRG and RSPG whether they were compared with one another or with both control groups. In the unipedal stance, subjects in the RSPG and SDHRG showed greater muscle activity in the anterior and posterior chains and hip abductors, and used less energy to maintain the stance than those in the CG55-80, regardless of lower limb dominance: decrease in the mediolateral range of COP displacement (Xrange) (hip abductor muscles) (p=02) and anteroposterior range of COP displacement (Yrange) (anterior and posterior chains) (p=3.49.10-3), 95% confidence ellipse area (Earea) of COP data (p=1.47.10-3), Plength (p=04) and Vavg (p=04). The RSPG had a smaller Earea than the SDHRG (p=04), demonstrating a better postural stability during the unipedal stance performed on the dominant operated leg. DISCUSSION: Our results were consistent with the literature on the benefits of rehabilitation after THA, thus confirming our hypothesis that rehabilitation normalized stabilometric parameters between D31-D45, depending on the subjects. These results provide new information regarding rehabilitation techniques to be implemented postoperatively after a THA. A home-based self-directed rehabilitation program is just as effective as an SP program in managing postural disorders. LEVEL OF EVIDENCE: II; randomized controlled trial with low statistical power.

Quantitative gait analysis after total hip arthroplasty through a minimally invasive direct anterior approach: A case control study.

INTRODUCTION: Total Hip Arthroplasty (THA) leads to excellent clinical and functional results. The Minimally Invasive Anterior Approach (MIAA) theoretically allows rapid recovery and a reduction in the need for rehabilitation, but alterations in muscle and static balance have previously been demonstrated. Kinetic, kinematic and muscular alterations have been shown to persist up to 1year postoperatively but data beyond 1year postoperatively is lacking. Thus, the objective of this study was to compare the data from Quantitative Gait Analysis (QGA) coupled with electromyography (EMG), of patients one year postoperatively with THA through MIAA, compared to an asymptomatic control group. HYPOTHESIS: We hypothesized that QGA and EMG parameters would not normalize beyond one year postoperatively. PATIENTS AND METHODS: Twenty-seven patients were recruited, including 15 subjects (64.6±6.6years) operated on by MIAA, who at 15.9±3.1months postoperatively, along with 12 asymptomatic control subjects (68.9±9.7years), who underwent QGA and maximal isometric muscle strength tests, coupled with EMG on the gluteus medius and maximus, Tensor Fascia Lata (TFL) and Sartorius muscles. The spatiotemporal parameters of walking (step length, walking speed, cadence, single leg support time), kinetics (vertical ground reaction forces, hip moments in the 3 planes) and kinematics (coxofemoral and pelvic amplitudes) were analyzed. RESULTS: The walking speed was lower on the non-operated side of the experimental subjects (0.96ms-1 compared to 1.13ms-1 for asymptomatic [p=0.018]), as was the step length on the operated side (0.53m compared to 0.60m for asymptomatic [p=0.042]). Maximal isometric muscle strength was lower in subjects operated on for the gluteus maximus and medius (p=0.004), compared to asymptomatic subjects. Moments were lower in the subjects operated on in extension (0.72Nm on the operated side, 0.75Nm on the non-operated side compared to 1.06Nm for asymptomatic [p=0.007 and p=0.024]) and lateral rotation (0.09Nm on the operated side, 0.05Nm on the non-operated side compared to 0.16Nm for asymptomatic subjects [p=0.009 and p=0.0005]). Hip adduction amplitudes were lower on the operated side compared to asymptomatic subjects (3.93° versus 9.14° for asymptomatic [p=0.005]). Pelvic amplitudes in the frontal plane were lower amongst operated subjects (0.44° against 1.97° for asymptomatic [p=0.041]). Pelvic amplitudes in the sagittal plane were higher in the operated subjects (15.74° on the operated side, 15.43° on the non-operated side compared to 9.65° for asymptomatic [p=0.041 and p=0.032]). DISCUSSION: Our initial hypothesis was validated, since walking deficits persisted beyond one year postoperatively after THA through MIAA. A decrease in maximal isometric muscle strength of the gluteus medius and gluteus maximus was observed, as well as an alteration of kinetic and kinematic parameters in the sagittal and frontal planes. The results were in agreement with the literature and reflected the establishment of compensatory mechanisms to overcome alterations in joint strength and range more than one year postoperatively. These results would allow rehabilitation programs to be more specific and would justify a study on the other approaches for THA. LEVEL OF EVIDENCE: III; non-randomized control trial.

MRI assessment of piriformis-sparing posterior approach in total hip arthroplasty.

INTRODUCTION: In total hip arthroplasty (THA), the posterior approach is the most common throughout the world. Dislocation is one of the main complications incurred, but the risk may be reduced by sparing posterior structures. Thus, piriformis-sparing posterior approaches (PSPA) were described, and satisfactory conservation of the muscle was reported. On the other hand, a recent cadaver study reported occult intrapelvic piriformis lesions in 91% of cases. In the light of this discordance, we performed pre- and postoperative MRI in THA by PSPA: 1) to assess the fatty infiltration of the piriformis induced by the approach, with particular attention to intrapelvic lesions; and 2) to assess fatty infiltration of the other periarticular muscles. HYPOTHESIS: The piriformis muscle will show little fatty infiltration following PSPA. MATERIALS AND METHODS: A continuous prospective single-surgeon series of THA by PSPA included 25 patients. MRI was performed preoperatively and at 3 months and 1 year postoperatively. Fatty infiltration was assessed on the Goutallier classification in all periarticular muscles. RESULTS: Preoperative MRI was lacking in 4 patients, who were excluded from analysis; 21 patients with MRI were thus analyzed. In the piriformis muscle, there was no significant change in fatty infiltration between preoperative and 3-month (p=0.29) or 1-year (p=0.41) MRI. Two of the 21 patients (9.5%) showed grade 3 or 4 fatty infiltration at 1 year, compared to 0/21 (0%) preoperatively; both showed sacral avulsion of the piriformis. Significant differences between preoperative and 1-year MRI were found for the obturator internus and externus, with grade 3 or 4 infiltration at 1 year in 14 cases for the obturator internus (14/21: 66.7%), in 3/21 for the obturator externus (14.3%) and in 6/21 for the quadratus femoris (28.6%), compared to respectively 0/21 (0%), 0/21 (0%) and 3/21 (14.3%) preoperatively. There were no significant differences for any of the other periarticular muscles. CONCLUSION: PSPA in THA ensured good conservation of the piriformis. There may, however, be rare and irreversible sacral lesions invisible intraoperatively. LEVEL OF EVIDENCE: IV; prospective case series.

Fatty muscle infiltration of the hip lateral rotator muscles following direct anterior minimally invasive total hip arthroplasty.

INTRODUCTION: There is no consensus as to the best surgical approach to use when doing total hip arthroplasty (THA). There has been renewed interest in recent years in so-called anatomic minimally invasive direct anterior approaches (DAA). However, their reduced impact has not been confirmed with imaging data. This led us to carry out a prospective study to 1) evaluate fatty infiltration (FI) of muscles around the hip joint and 2) analyze how this FI changes over time. HYPOTHESIS: THA done by the DAA induces FI of the anterolateral muscles around the hip adjacent to the approach. MATERIAL AND METHODS: A continuous case series of THA by DAA using a traction table was done by a single experienced surgeon. MRI images (GE Optima* MR360 1.5T) were taken preoperatively, then at 3 months and 1 year after the THA surgery. Muscle FI was classified as described by Goutallier by an independent radiologist on all the muscles around the hip joint. A Wilcoxon test was used to compare the preoperative MRI data to the data at 3 months and 1 year postoperative. RESULTS: Sixty-nine MRI examinations were done in 23 patients. Two were not interpretable because the patient moved during the preoperative acquisition. No intraoperative or postoperative complications were reported. None of the patients had hip pain or limped at 1 year postoperative. The FI was significantly worse from the preoperative MRI to the 3-month postoperative MRI (p=0.02) and 1-year MRI (p=0.0007) in the internal obturator muscle and at 1 year in the piriformis muscle (p=0.04). There was no significant difference for the other muscles. The rectus femoris, superior and inferior gemellus muscles and the quadratus femoris could not be analyzed. DISCUSSION: Our hypothesis was not confirmed, although we had a paradoxical finding of muscle FI in the posterior lateral rotator muscles not the anterolateral muscles after THA by DAA. These lesions may be secondary to detachment or denervation of these muscles when elevating the femur to prepare the femoral canal or insert the stem. LEVEL OF EVIDENCE: IV; Prospective case series.

Total shoulder arthroplasty using the superior approach: influence on glenoid loosening and superior migration in the long-term follow-up after Neer II prosthesis installation.

Glenoid component loosening and superior humeral translation are common after Neer II total shoulder arthroplasty using the anterior approach. To determine whether the superior approach reduced these complications, we retrospectively reviewed 20 shoulders in 16 patients. Both components were cemented. Patient satisfaction, unweighted Constant score, and imaging studies were evaluated at a mean of 3.5 years and at a mean of 11.1 years. Fourteen patients were satisfied or very satisfied. The mean unweighted Constant score improved from 25/100 preoperatively to 57/100 after 3.5 years and to 51/100 after 11.1 years. Pain relief contrasted with low strength. Radiolucent lines appeared around 95% of glenoid components and 20% of humeral stems. Computed tomography showed severe glenoid osteolysis in 3 of 13 shoulders. Humeral superior translation did not occur. This study confirms the glenoid component fixation issue. The superior approach may reduce the risk of humeral superior translation and radiologic glenoid component loosening.

Electromyographic study of hip muscles involved in total hip arthroplasty: Surprising results using the direct anterior minimally invasive approach.

BACKGROUND: The functional and clinical benefit of minimally invasive total hip arthroplasty (THA) is well-known, but the literature reports impaired gait and posture parameters as compared to the general population, especially following use of the anterior minimally invasive approach, which has more severe impact on posture than the posterior approach. The reasons for this impairment, however, remain unexplained. We therefore conducted a surface electromyography (sEMG) study of the hip muscles liable to be affected by arthroplasty surgery: gluteus maximus (GMax), gluteus medius (GMed), tensor fasciae latae (TFL), and sartorius (S). The study addressed the following questions: (1) Is bipodal and unipodal GMed activity greater following anterior THA than in asymptomatic subjects? (2) Is a single manual test sufficient to assess maximal voluntary contraction (MVC) in hip abductors (GMax, GMed, TFL) and flexors (TFL, S)? HYPOTHESIS: Bipodal and unipodal GMed activity is greater following anterior THA than in asymptomatic subjects. METHOD: Eleven patients with anterior THA and 11 asymptomatic subjects, matched for age, gender and body-mass index, were included. Subjects underwent 3 postural tests: bipodal, eyes closed (BEC), unipodal on the operated side (UOP), and unipodal on the non-operated side (UnOP), with unipodal results averaged between both sides in the asymptomatic subjects. Data were recorded from 4-channel EMG and a force plate. EMG test activity was normalized as a ratio of MVC activity. RESULTS: Postural parameters (mean center of pressure displacement speed) were poorer and sEMG activity higher in anterior THA than asymptomatic subjects (p<0.005). On the BEC test, GMax and GMed activity was higher on both operated and non-operated sides than in asymptomatic controls (respectively, 0.15±0.12 and 0.12±0.6 versus 0.07±0.06 for GMax, and 0.13±0.08 and 0.13±0.08 versus 0.08±0.05 for GMed; p<0.05). On unipodal tests, both UOP and UnOP GMed activities were higher than in controls (respectively, 0.51±0.3 and 0.48±0.27 versus 0.28±0.13; p<0.04); GMax and TFL activities were higher than in controls only on the UOP tests (respectively, 0.49±0.43 versus 0.24±0.18, and 0.23±0.17 versus 0.12±0.16; p<0.05). DISCUSSION: sEMG activity in the hip abductors, which are the main stabilizing muscles for the pelvis, is increased following anterior THA, in parallel with impaired postural parameters. This finding may be due to intraoperative TFL and S neuromuscular spindle lesion. The present preliminary study is to be followed up by a comparison of all 3 common minimally invasive approaches (anterior, anterolateral and posterior) using the same study protocol. LEVEL OF EVIDENCE: III, prospective case-control study.

Comparing three attachment systems used to determine knee kinematics during gait.

This work compared three attachment systems (AS) designed to minimize soft tissue artefacts in gait analysis measurements. The systems' displacement for different knee flexion angles and after 50 gait cycles was investigated using an EOS low dose biplanar X-ray system. Eighteen subjects (six per AS) were equipped with one AS and placed in five positions. Frontal and profile views were taken for each position. The bones' 3D model and the AS's position were obtained from stereoradiographic reconstructions. The AS's relative position to the underlying bone were computed and interpreted in the anatomical coordinate systems (CS). The AS appeared to be stable in the frontal and sagittal plane (under 1.5 degrees average displacement around the underlying bones) but unstable in the axial plane (over 6 degrees average displacement). The average translation along the femoral and tibial diaphysis was 4.5mm and 2.7 mm, respectively. Femoral system B translated significantly less along the diaphysis than the other AS. Concerning the axial rotation, system C appeared to present the most important displacement but there was no statistically significant difference. Systems A and B's rotation in the transverse plane correlated to the knee flexion angle. For the tibia, system B was more stable than systems A and C (p=0.04). On the whole, system B appeared to be the most stable system. This study highlights the fact that no system can limit displacement in the transverse plane.

Influence of lower-limb torsion on long-term outcomes of tibial valgus osteotomy for medial compartment knee osteoarthritis.

BACKGROUND: The results of tibial osteotomy used to treat osteoarthritis of the medial compartment of the knee deteriorate over time even when the initial correction is optimal. Studies have shown that tibial and femoral torsion and the femorotibial index (tibial torsion minus femoral torsion) contribute, together with coronal malalignment, to the development of single-compartment knee osteoarthritis. The objective of our study was to evaluate the impact of femoral and tibial torsion and of coronal realignment on the long-term clinical and radiographic outcomes of valgus tibial osteotomy. METHODS: A function score was calculated for sixty-eight patients at a mean of thirteen years after the osteotomy. Anteroposterior single-leg-stance radiographs were used to evaluate loss of the femorotibial joint space. Goniometry was used to measure coronal malalignment preoperatively, at one year, and at the time of the last follow-up, and postoperative computed tomography was performed to measure femoral anteversion and tibial torsion and to calculate the femorotibial index. We looked for associations linking body mass index, initial loss of joint space, coronal malalignment, femoral and tibial torsion, the femorotibial index, and functional outcomes. RESULTS: Worse outcomes were associated with changes in coronal alignment (>/=2 degrees ) over time, which were associated with deterioration of the femorotibial space. Femoral anteversion was significantly greater in patients in whom valgus increased over time than in those in whom valgus decreased over time. Stability of coronal alignment seemed to be dependent on a linear relationship between the femorotibial index and the degree of postoperative realignment. A body mass index of >25 kg/m(2) was associated with a long-term loss of coronal realignment. Preoperative loss of the medial femorotibial joint space, coronal alignment at one year, and age were not associated with secondary malalignment or functional outcomes. CONCLUSIONS: Long-term success of a valgus tibial osteotomy is related to the stability over time of the postoperative coronal realignment. Therefore, the results of our study suggest that modifying the realignment according to the extent of femoral anteversion may improve long-term outcomes.

Shoulder surgery: from cuff repair to joint replacement. An update.

REPAIRING FULL THICKNESS CUFF TEARS.--Despite the sound rationale for repairing full-thickness rotator cuff tears, the procedure may fail to restore cuff integrity, which is indispensable to optimal cuff function. The functional role of each cuff muscle and the factors associated with anatomic failure (particularly those related to the muscles and tendons) provide a basis for rational patient selection and for determination of the best surgical strategy on a case-by-case basis. SHOULDER ARTHROPLASTY IN PATIENTS WITH GLENOHUMERAL JOINT DISEASE.--Total shoulder arthroplasty in patients with glenohumeral joint disease provides better outcomes than humeral hemiarthroplasty. The choice between a semi-constrained total prosthesis and a reverse constrained total prosthesis should be based on the nature of the joint disease (either centered humeral head or normal cuff function or migrated humeral head and abnormal cuff function). At present, only the semi-constrained total prosthesis has been proved effective in the long-term when used in a patient with a centered humeral head and active cuff. This provides additional support for repairing cuff tears whenever possible in patients who are still young.

[Bone morphing system for rotational alignment in total knee arthroplasty].

OBJECTIVE: To investigate the qualitative rotation alignment of components in total knee arthroplasty and the accuracy and the effectiveness of Bone Morphing computer assisted system when qualitatively practicing. METHODS: From November 2002 to June 2003, 21 patients with three compartments osteoarthritis (21 knees) were treated by primary total knee arthroplasty after the conservative medical treatment failed, with the assistance of a "Bone Morphing" Ceravision System, implanted posterior stabilized total knee prosthesis. Twenty-one patients included 5 males (5 knees) and 16 females (16 knees) with an average age of 72.4 years (64-79 years). The locations were left knee in 10 cases and right knee in 11 cases. The patients suffered from knee pain and limitation of movement from 2 to 10 years. There were 14 genu varum and 7 genu valgum preoperatively. The relative preoperative, intraoperative and postoperative data from clinical check-up, the X-ray films and the intraoperative components rotational alignment real-time records in CD Rom were analyzed. RESULTS: All operative incisions healed up by first intension. Twenty-one patients were followed up 12-16 months (mean 13.3 months). For the achievement of proper lower limb alignment and normal frontal laxity of knee, rotational alignment of femoral components was from internal rotation (IR) 1 degree to external rotation (ER) 5 degrees, tibial components from IR 0 degree to ER 5 degrees. In patients with genu varum, the rotational alignment of the femoral components was ER 1 degree-ER 5 degrees, of tibial components ER 2 degrees-ER 5 degrees. In patients withgenu valgum, the rotational alignment of femoral components was IR 1 degree-ER 4 degrees, of tibial components IR 0 degree-ER 4 degrees. After 3 months of operation, the mean flexion angle measured as range of motion (ROM) was 115 degrees (105-130 degrees), the frontal laxsity measured as 0.2-0.5 cm (mean 0.27 cm) of internal laxity and 1.0-2.5 cm (mean 1.7 cm) for external laxity, there were no knee pain, paterllar instability or dislocation and abnormal knee frontal laxity. CONCLUSION: Using Bone Morphing computer-assisted system can optimise the individual components rotation alignment accurately.

[Bone morphing system for ligament balancing in total knee arthroplasty].

OBJECTIVE: To investigate effectiveness of applying the Bone Morphing based image-free computer-assisted system for the ligament balancing management in the total knee arthroplasty (TKA). METHODS: Between November 2002 and June 2003, twenty-one posterior stabilized total knee prostheses (Craver, France) were implanted in 21 patients using the Bone Morphing based image-free Ceravision system. This cohort included 5 men and 16 women with an average age of 72.4 years, two undergoing high tibial osteotomy and 1 undergoing distal femoral osteotomy before. The preoperative deviation was measured by the full-length AP X-rays. The knees were in varus deviation in 14 patients and in valgus deviation in 7 patients, with an average of 2.36 degrees (varus 13 degrees-valgus 13 degrees). The frontal X-rays of the knee were assessed, the mean value of the varus force-stress test was 8.47 degrees (varus 2 degrees-varus 20 degrees), and the mean value of the valgus force-stress test was 3. 63 degrees (varus 7 degrees-valgus 12 degrees). RESULTS: With the Ceravision-recorded data, the intraoperative alignment was assessed, the mean lower limb axis was 3.33 degrees (varus 12 degrees-valgus 10 degrees), and compared with the preoperative data, the difference was significant (P < 0.05); the mean value of the varus force-stress test was 6. 47 degrees (varus 0 degree - varus 24 degrees), the mean value of the valgus force-stress test was 4.32 degrees (varus 8 degrees-valgus 15 degrees), and compared with the preoperative data, the difference was significant (P < 0.05). The post-prosthetic alignment on Ceravision with a deviation of 0.175 degrees (varus 2 degrees-valgus 3 degrees) was compared with the postoperative alignment by the full-length AP X-rays, with a deviation of 0.3 degrees (varus 3.5 degrees-valgus 1.5 degrees), the difference wasn't significant (P > 0.05). The clinical check-up performed 3 months after operation showed that the average range of movement (ROM) was 115 degrees (105-130 degrees), the mean frontal laxity was 0.27 mm (0.2-0.5 mm). The femoral and tibial components were implanted in the satisfactory 3 dimensional position without ligament imbalance in all the patients, and there were no instability or patella complications. CONCLUSION: Utilization of the Bone Morphing based image-free computer-assisted system can achieve an accurate component 3 dimensional alignment, optimal bone resection, optimal control of surgical decision in releasing the soft tissues, rotating the femoral component to gain an extension/flexion rectangular gap, and managing the ligament balancing so as to achieve a satisfactory initial clinical outcome. This system can be routinely used in the TKA.

Surgical treatment of destructive cervical spondyloarthropathy with neurologic impairment in hemodialysis patients.

STUDY DESIGN: We have retrospectively reviewed 11 chronic hemodialysis patients with cervical destructive spondyloarthropathy responsible for neural impairment 1 year after surgery and at last follow-up. OBJECTIVE: To evaluate clinical and radiologic outcomes, and necessity of vertebral block excision. SUMMARY OF BACKGROUND DATA: Destructive spondyloarthropathy of the cervical spine is associated with long-term hemodialysis for chronic kidney failure. Spinal cord compression and neurologic troubles occur in a few cases. Surgical treatment remains controversial because these are debilitated patients with multiple organ failures. METHODS: All 11 patients had unstable cervical spondylolisthesis, and 10 had kyphotic vertebral fusion involving at least 2 vertebrae. We performed interbody bone grafting (cement in 1 case) and stabilized with a plate. In 6 of the 10 patients with vertebral block, excision of the block was performed. RESULTS: No patients were lost to follow-up. One patient died 2 days after the operation. There were 2 other patients who required early surgical revision (i.e., a corporectomy followed by early graft expulsion). Bone healing settled in all patients. One year after surgery, patients had almost complete resolution of the pain and satisfactory neurologic recovery. Improvement was evaluated according to the Nurick classification. CONCLUSION: Functional and neurologic results were similar whether the patients did or did not undergo vertebral block excision, suggesting that stabilizing the unstable level may be sufficient in patients with neurologic impairment. Excision of spontaneous vertebral blocks should be avoided to minimize the morbidity of surgery in these debilitated patients with a limited life expectancy.

Influence of cuff muscle fatty degeneration on anatomic and functional outcomes after simple suture of full-thickness tears.

Two hundred twenty shoulders with a rotator cuff tear repaired by simple tendon-to-bone suture were analyzed to determine whether the severity of presurgical fatty degeneration had an influence on their anatomic and functional outcome. Fatty degeneration was evaluated for each muscle with the 5-stage grading system developed by Goutallier et al. A global fatty degeneration index (GFDI), the mean value of the 3 muscles, was calculated for each shoulder. Cuff integrity was evaluated by magnetic resonance imaging (116 cases) or computed arthrotomography scan (104 cases) at a mean 37 months' follow-up, and functional outcomes were evaluated with the Constant score. A recurrent tear was found in 79 cases (36%) and was more frequently encountered in posterosuperior tears. The likelihood of a recurrent tear was greater for tendons whose muscle showed fatty degeneration greater than grade 1. Fatty degeneration of the infraspinatus or subscapularis muscles had an influence on supraspinatus tendon outcome. A GFDI lower than 0.5 was necessary to yield less than 25% retears. The mean global Constant score was 75 at revision, significantly lower when a retear was present (70.5 versus 77.5). In the subgroup of watertight cuffs, it was lower when GFDI was higher. Fatty degeneration is an important prognostic factor in rotator cuff surgery.