Does hip joint positioning affect maximal voluntary contraction in the gluteus maximus, gluteus medius, tensor fasciae latae and sartorius muscles?

BACKGROUND: Minimally invasive total hip arthroplasty (THA) is presumed to provide functional and clinical benefits, whereas in fact the literature reveals that gait and posturographic parameters following THA do not recover values found in the general population. There is a significant disturbance of postural sway in THA patients, regardless of the surgical approach, although with some differences between approaches compared to controls: the anterior and anterolateral minimally invasive approaches seem to be more disruptive of postural parameters than the posterior approach. Electromyographic (EMG) study of the hip muscles involved in surgery [gluteus maximus (GMax), gluteus medius (GMed), tensor fasciae latae (TFL), and sartorius (S)] could shed light, the relevant literature involves discordant methodologies. We developed a methodology to assess EMG activity during maximal voluntary contraction (MVC) of the GMax, GMed, TFL and sartorius muscles as a reference for normalization. A prospective study aimed to assess whether hip joint positioning and the learning curve on an MVC test affect the EMG signal during a maximal voluntary contraction. HYPOTHESIS: Hip positioning and the learning curve on an MVC test affect EMG signal during MVC of GMax, GMed, TFL and S. METHODS: Thirty young asymptomatic subjects participated in the study. Each performed 8 hip muscle MVCs in various joint positions recorded with surface EMG sensors. Each MVC was performed 3 times in 1 week, with the same schedule every day, controlling for activity levels in the preceding 24h. EMG activity during MVC was expressed as a ratio of EMG activity during unipedal stance. Non-parametric tests were applied. RESULTS: Statistical analysis showed no difference according to hip position for abductors or flexors in assessing EMG signal during MVC over the 3 sessions. Hip abductors showed no difference between abduction in lateral decubitus with hip straight versus hip flexed: GMax (19.8±13.7 vs. 14.5±7.8, P=0.78), GMed (13.4±9.0 vs. 9.9±6.6, P=0.21) and TFL (69.5±61.7 vs. 65.9±51.3, P=0.50). Flexors showed no difference between hip flexion/abduction/lateral rotation performed in supine or sitting position: TFL (70.6±45.9 vs. 61.6±45.8, P=0.22) and S (101.1±67.9 vs. 72.6±44.6, P=0.21). The most effective tests to assess EMG signal during MVC were for the hip abductors: hip abduction performed in lateral decubitus (36.7% for GMax, 76.7% for GMed), and for hip flexors: hip flexion/abduction/lateral rotation performed in supine decubitus (50% for TFL, 76.7% for S). DISCUSSION: The study hypothesis was not confirmed, since hip joint positioning and the learning curve on an MVC test did not affect EMG signal during MVC of GMax, GMed, TFL and S muscles. Therefore, a single session and one specific test is enough to assess MVC in hip abductors (abduction in lateral decubitus) and flexors (hip flexion/abduction/lateral rotation in supine position). This method could be applied to assess muscle function after THA, and particularly to compare different approaches. LEVEL OF EVIDENCE: III, case-matched study.

Short-term comparison of postural effects of three minimally invasive hip approaches in primary total hip arthroplasty: Direct anterior, posterolateral and Röttinger.

INTRODUCTION: There is renewed interest in total hip arthroplasty (THA) with the development of minimally invasive approaches. The anterior and Röttinger approaches are attractive for their anatomical and minimally invasive character, but with no comparative studies in the literature definitely suggesting superiority in terms of quality of functional recovery. We therefore performed a case-control study, assessing: 1) whether the postural parameters of patients operated on with the anterior, Röttinger and posterior minimally invasive approaches were similar to those of asymptomatic subjects, and 2) whether there were any differences in postural parameters between the three approaches at short-term follow-up. HYPOTHESIS: We hypothesized that the anterior and Röttinger approaches are less disruptive of postural parameters than the posterior approach. METHODS: Seventy subjects (44 primary THA patients and 26 asymptomatic control subjects) were enrolled. Operated subjects were divided into 3 experimental groups corresponding to the 3 minimally invasive approaches: posterior (n=14), anterior (n=15) and Röttinger (n=15). Two single-leg stance tests (left followed by right leg stance; 10s per test) were carried out on a stabilometric platform, within 2months after surgery for all THA patients, and for controls. Six significant parameters were selected for statistical analysis: test performance, mediolateral and anteroposterior displacements of the center of pressure (CP), path length, average CP displacement speed, and the ellipse containing 95% of CP projections. Non-parametric statistical tests were used to compare groups. RESULTS: There was no difference between the 3 study groups and the control group according to age, gender, BMI, or side (or between study groups regarding WOMAC score). No significant differences between approaches were found for success on postural tests (P=0.14). Subjects operated on with the anterior or Röttinger approach showed significant differences from asymptomatic subjects for 2 postural parameters: path length (Röttinger P=0.04, anterior P=0.03) and average CP displacement speed (Röttinger P=0.04, anterior P=0.03). Subjects operated on through the posterior approach showed no significant differences from asymptomatic subjects. DISCUSSION: The study hypothesis, that the anterior and Röttinger approaches for hip arthroplasty are less disruptive of postural parameters than the posterior approach, was not confirmed. The anterior and Röttinger approach groups showed higher average CP displacement speed and path length, suggesting that they use up more energy resources to maintain static balance. The posterior approach had the least impact on postural parameters in the first 2 postoperative months. LEVEL OF EVIDENCE: III, case-control study.

Transsupraspinatus arthrotomy through an enlarged transacromial approach for total shoulder replacement.

The authors describe a step-by-step technique for anatomic total shoulder arthroplasty using transsupraspinatus arthrotomy via the enlarged transacromial approach. This technique seems ideal to ensure adequate postoperative tensional balance of the infraspinatus and the subscapularis, which is critical for the rotator cuffs to function properly and to achieve optimal arthroplasty stability. Reviewing these different steps helps understanding each rotator cuff individual component's contribution to achieve optimal arthroplasty stability.

[Total knee arthroplasty with bicruciate preservation: Comparison versus the same posterostabilized design at eight years follow-up]. / Prothèse totale de genou Hermès conservant les deux ligaments croisés : comparaison avec la version postérostabilisée au recul de huit ans.

PURPOSE OF THE STUDY: The purpose of this study was to determine the functional, clinical and radiographic results obtained with total knee arthroplasty (TKA) preserving both cruciate ligaments using the Hermès prosthesis with a fixed plateau. Mid-term results at eight years mean follow-up were compared with the outcome achieved at the same follow-up with posterior-stabilized (PS) Hermès TKA with a fixed bearing. MATERIAL AND METHODS: The results of a continuous series of 41 TKA with bicruciate preservation implanted between 1991 and 1994 with and extra-articular distractor were analyzed at one and eight years follow-up using the IKS scores and radiographic findings. A change in the medial femoral and tibial angles greater than 2 degrees was considered to indicate implant loosening. Results were compared with those of a continuous series of TKA with PS knees implanted during the same period without a distractor and with independent bone cuts. The patients and operated knees were not different between the two groups: femoral and tibial implants were cemented in the large majority of knees with press-fit metal-backed patellar implants and comparable postoperative alignment (179 degrees ). RESULTS: The knees with the TKA bicruciate preservation were painful (37.6%) and exhibited limited mobility (106 degrees ) from the first postoperative year, but the function score was good (80.8 points). Four tibial implants exhibited varus displacement greater than 2 degrees (mean 6.5 degrees ) and six femoropatellar changes were noted (five with lateral displacement of the patella on a non-cemented patellar implant). The knees with a posterior-stabilized TKA were almost all pain-free (44.3 points) and exhibited better range of motion (113.8 degrees ). Among the PS designs, there was the same number of tibial loosenings which were favored, as for the bicruciate preservation TKA, by excessive frontal laxity in extension at one year. Femoropatellar modifications appeared to be less common with the posterior PS knees (one event). There was no measurable polyethylene wear. DISCUSSION: The good clinical and radiological results obtained by Cloutier, who used the same distractor for the same TKA implants with bicruciate preservation, suggest that the less favourable clinical results and the radiographic modifications of the patellofemoral component, which were more frequent in our bicruciate preserved implants, can be explained by an inadequate use of the distractor. By creating greater ligament tension (which we attempted to achieve), the independent bone cuts do not allow perfect respect of the dynamics of the cruciate ligaments compromising the frontal femoropatellar mechanics. CONCLUSION: The risk of prosthetic loosening is not greater with TKA bicruciate sparing designs than with PS knees when the postoperative frontal laxity and the frontal realignment are satisfactory. They enabled better function but greater operative precision is required to achieve pain-free knees with a good range of motion.

Tension-free cuff repairs with excision of macroscopic tendon lesions and muscular advancement: results in a prospective series with limited fatty muscular degeneration.

Recurrent tears after rotator cuff repairs are frequent. These could be influenced by excessive tension on a degenerated tendinous stump and by fatty degeneration of the cuff muscles. The goal of this study was to evaluate the anatomic and functional results of tension-free cuff repairs with the excision of macroscopic tendon lesions in a series with limited muscular fatty degeneration of the infraspinatus and a global fatty degeneration index of rotator cuff muscles equal to or lower than 2. We studied 27 tears, comprising 13 cases involving both supraspinatus and infraspinatus tears, 13 cases with 3-tendon tears, and 1 case with only a supraspinatus tear. All shoulders were operated on through a transacromial approach easily repaired with 2 titanium screws with washers. To obtain a repair without tension, a single advancement was performed in 20 cases and a double advancement of both the supraspinatus and infraspinatus was done in 7 cases. The shoulders were evaluated clinically preoperatively and postoperatively with the non-weighted Constant score and anatomically with computed arthrotomography scans. The mean age at operation was 59.5 years, and the length of follow-up ranged from 1 to 4 years. Of the cuffs, 23 (85%) were watertight 1 year after surgery. No predictive factor of retear could be found. The functional improvement was statistically significant only for watertight cuffs, with an improvement of the Constant score from 57.8 to 75. The only predictive factor of functional outcome in this watertight group was the preoperative Constant score. Single and double advancements yielded similar functional results regardless of the extent of the initial tear, provided that the cuff was watertight at revision.

[Histological lesions of supraspinatus tendons in full thickness tears of the rotator cuff]. / Les lésions histologiques des tendons des supraspinatus dans les ruptures transfixiantes de la coiffe des rotateurs.

PURPOSE OF THE STUDY: Iterative tears after simple tendon bone suture of transfixiant ruptures of the rotator cuff are frequent. The frequency of iterative ruptures had seemed to be correlated to the importance of the preoperative fatty degenerations of the cuff muscles. But fatty degeneration cannot account for iterative ruptures occurring with no or little preoperative muscle fatty degeneration. The authors have tried to know if iterative ruptures could also be accounted for by the presence on repaired tendinous stumps of histological lesions which are known to lower their mechanical quality, and if such was the case, they have tried to know what could be the impact of these lesions on the repairing technique by suturing cuff ruptures. MATERIAL AND METHOD: Thirty-two distal stumps of ruptured supraspinatus, resected on more than 1 cm to eliminate macroscopic tendinous lesions (thin, lacerated, cleaved, hardened or whitish tendons) and to reach a new stump, slightly bleeding and thick enough to hold the stitches correctly, have been studied on longitudinal histological slides. RESULTS: All the tendinous resected stumps had histological anomalies: dilacerations lesions of the conjunctive tissue, fatty infiltrations, necrosis, scar lesions and micro calcifications were found. The histological lesions were often associated. The histological lesions were an average 4 mm shorter than those of the tendinous resection. In 18 cases however the whole of the resected tendon was histologically abnormal. DISCUSSION: Tendinous histological lesions found on the whole or almost the whole length of the macroscopically abnormal tendinous stumps diminish the mechanical quality of the tendons. Insufficient resection of the tendinous stumps leaving macroscopical lesions and therefore histological lesions could account for iterative ruptures in the first post operative year. Yet complete resection of the macroscopically abnormal tendinous stump does not entail that the neo tendinous stump to be repaired is histologically normal. This encourages to put the stitches well within the zone of the tendinous resection and to bury the tendinous stumps into a highly vascular bony trough. But tendinous resection although logical from the histological and mechanical point of view widens the rupture of the cuff to be repaired. It can make sutures under tension, which can entail iterative ruptures. Musculo-tendinoplasty appears then necessary to perform sutures without tension. CONCLUSION: Histological lesions of tendinous stumps of cuff ruptures correspond roughly to tendinous macroscopic lesions. They could be at the origin of iterative ruptures that take place after simple tendon-bone sutures of ruptured cuffs which are not accounted for by muscular fatty degeneration. They could also partly account for iterative ruptures taking place when pre operative fatty degeneration is evident. It seems logical to resect macroscopically abnormal tendinous stumps before performing a suture. But the tendon-bone suture without tension is then often possible only with musculo-tendinoplasties.

[Long-term results of alumina-on-alumina total hip arthroplasty]. / Résultats à long terme du couple de frottement alumine/alumine sur 98 prothèses de hanche cimentées.

PURPOSE OF THE STUDY: Mechanical failure in total hip arthroplasty is usually related to aseptic loosening itself related to wear particles as seen with polyethylene bearings. Alumina has bee proposed to avoid wear problems. In vitro and mid-term clinical studies have shown tribological advantages but early acetabular fixation remains an issue. Since alumina-on-alumina bearings are currently used with new fixation techniques, updated evaluations of older series are informative regarding the long-term tolerance of alumina in vivo. MATERIAL AND METHODS: We investigated 104 consecutive alumin-on-alumina cemented total hip arthroplasties (Cervaer-Osteal, Roissy, France) implanted 20 years ago in 81 patients (from 1979 to 1983). A32-mm alumina femoral head was used. The alumina acetabular socket and the titanium femoral stem were cemented. The Postel-Merle-d'Aubigne score was used for clinical evaluation. Radiological wear and development of osteolysis or loosening were noted for establishing actuarial curves. When accessible, histological samples from revision procedures were analyze. RESULTS: Six infected cases were not taken into account for data analysis. The average follow-up was 11 years, reaching 18 years in 38 cases. Twenty-three hips were revised for changing 23 acetabular sockets, 12 femoral heads, and one femoral stem. We noted one femoral head fracture, 24 definite acetabular loosenings, 12 probable acetabular loosenings, and 3 definite femoral loosenings. Radiological acetabular osteolysis was present in 4 cases, always limited to De Lee zone 1, and associated with loosening. Radiological wear was below eye detection. Periprosthetic tissue showed non-specific histological reactions to cement particles. Survival rate at 20 years was 62.8% [49.3-76.2%], in terms of revision 57.1% [42.5-71.7%] and 95.2% [89.9-100%] in terms of definite acetabular and femoral loosening. DISCUSSION: Besides the high rate of cemented fixation failure of the socket, loosened and non-loosened cases showed an excellent long-term tolerance of the alumina-on-alumina bearing with normal wear and osteolysis. This may also have protected the femoral component from complications. This study confirms in vivo the long-term tribological benefit of the alumina-on-alumina bearing in total hip arthroplasty and suggests that acetabular fixation should be improved to achieve full benefit.

[Retro-trochlear wedge reduction trochleoplasty for the treatment of painful patella syndrome with protruding trochleae. Technical note and early results]. / Trochléoplastie d'enfoncement par résection cunéiforme rétro-trochléenne dans le traitement des rotules douloureuses avec saillie des berges trochléennes. Note technique et premiers résultats.

PURPOSE OF THE STUDY: Patients with painful patella syndrome without objective instability are often treated by section of the lateral retinacular of the patella or advancement osteotomy of the tibial tuberosity with less than satisfactory mid-term results. One explanation of the persistent pain could be hyperpression within the femoro-patellar joint due to excessive protrusion of the trochleae (>=7 mm). We propose retro-trochlear wedge resection to achieve reduction trochleoplasty. The wedge is cut with a superior base so the trochlear angle remains unchanged. We describe here the operative technique and report early results at more than two years follow-up. MATERIAL AND METHOD: We reviewed retrospectively 12 knees treated with trochleoplasty for painful patella syndrome. Eleven of these knees had had previous operations for objective (n=9) or potential (n=2) patellar instability. Mean follow-up was 4 years (range 2-6). A complete pre- and postoperative radiological work-up was obtained for all knees including 30 degrees flexion femoropatellar views and computed tomography measurements of TA-GT value at 30 degrees flexion. Functional outcome was studied with the Arpege scale. Trochleoplasty was performed via an anterolateral approach and was associated with frontal translation of the tibial tuberosity if the preoperative TA-GT was not in accord with the trochlear angle. RESULTS: Functional outcome improved during the first two postoperative years then stabilized. Improvement in pain and instability was statistically significant. Functional outcome was scored good or very good for nine knees. The two failures occurred in the oldest patients whose knees had had several operations. Mean trochlear protrusion was 8 mm preoperatively and 3 mm postoperatively. All trochleoplasties healed; there was no trochlear necrosis. DISCUSSION: The described trochleoplasty has an advantage over classical reduction trochleoplasty because it does not modify the trochlear angle. In addition, it is quantifiable. It is biomechanically more logical than advancement of the tibial tuberosity. In our patients, the trochlear protuberance was reduced to 3 mm. Associated with correction of mechanical femoro-patellar anomalies in the frontal plane, this trochleoplasty can provide good relief even in patients with persistent pain in previously operated knees treated for objective or potential patellar instability or for simple patellar pain.