Release-reinsertion of the biceps femoris tendon onto the fibula in biceps femoris impingement on the knee with or without snap.

Ectopic insertions of the biceps femoris tendon at the knee can cause impingement with the fibular head, leading to pain with or without snap. There are several variant insertions that have recently been described and classified. Pain syndrome primarily affects athletic patients, often cyclists, disrupting sports practice. Diagnosis is difficult and often late. Medical treatment is often disappointing, leading to surgery. The aim of surgery is to remove the impingement between the ectopic insertion of the biceps tendon and the fibular head, by releasing the unduly anterior tendon, sometimes from the tibia and reinserting it in an anteroposterior tunnel in the fibular head. This reinsertion in a physiological zone without impingement is then fixed by an interference screw.

Biceps femoris snapping and friction on the fibular head secondary to abnormal distal tendon insertion: 15 cases and a literature review.

INTRODUCTION: Abnormal biceps femoris distal tendon insertion can cause tendon snapping, as is well-known in the literature. The presenting symptom is lateral knee pain, often during sports activities and cycling in particular. The present study tested two hypotheses: abnormal biceps femoris insertion on the fibular head may cause painful friction without clinical snapping, whether visible, audible or palpable; surgical correction achieves good results for pain and return to sport, regarding both snapping and friction. MATERIAL AND METHODS: Between 2006 and 2017, 11 patients were managed for pain secondary to abnormal biceps femoris insertion. In 4 cases, pain was bilateral, resulting in a total of 15 knees: 9 with snapping (in 6 patients), and 6 with friction syndrome without snapping (in 5 patients). All 6 patients with snapping were male, with a mean age of 29 years. Friction without snapping concerned 3 female and 2 male patients, with a mean age of 30 years. Study data included type and level of sport, clinical signs, imaging, type and results of treatment, and type of abnormality. RESULTS: The insertion abnormality consisted in excessively anterior insertion in the fibular arm in 6 cases, in predominantly tibial insertion in 2 cases, and in isolated tibial insertion in 4 cases. Surgery mainly consisted inrelease and reinsertion of the distal biceps femoris tendon (in 7 cases). All patients were able to return to sport. The mechanism underlying snapping and friction was the same: distal biceps tendon friction on the fibular head secondary to unduly anterior fibular or predominantly or exclusively tibial insertion. DISCUSSION: The literature reports 24 cases, all of snapping, with between 1 and 3 cases per author. These findings were compared with the present results. With or without snap, symptoms are secondary to abnormal tendon insertion and to activity or sport requiring repeated knee flexion greater than 90°. CONCLUSIONS: (1) Case studies show that lateral knee pain by friction on the fibular head is not systematically accompanied by snapping. (2) In all reports and in the present series, surgery was highly effective on snapping and pain, and patients returned to sport at their previous level. LEVEL OF EVIDENCE: IV.

Same-stage total knee arthroplasty and osteotomy for osteoarthritis with extra-articular deformity. Part II: Femoral osteotomy, prospective study of 6 cases.

BACKGROUND: Same-stage (1S) total knee arthroplasty (TKA) and femoral osteotomy (FO) may deserve consideration in patients with both knee osteoarthritis and severe extra-articular knee deformity (EKD). The objective of this study was to assess clinical and radiological outcomes and morbidity (complications and revisions) in 6 patients managed with S1-TKA-FO. HYPOTHESIS: 1S-TKA-FO produces satisfactory outcomes and is not associated with higher morbidity rates compared to two-stage TKA-TO or TKA with intra-articular EKD correction, while also significantly shortening total treatment duration. MATERIAL AND METHODS: A prospective study was performed in 6 patients managed with 1S-TKA-FO between 1999 and 2011; mean age was 64 years (range, 59-72 years) and mean body mass index was 29.5 (range, 26-35). The EKD was consistently greater than 10°. The cause was post-traumatic mal-union in 4 patients, constitutional EKD in 1 patient, and FO in 1 patient. In each patient, the clinical International Knee Society (IKS) score and the hip-knee-ankle angle (HKA), femoral mechanical angle (FMA) and tibial mechanical angle (TMA), were recorded prospectively before and after surgery. RESULTS: A long uncemented extension stem was used in all 6 patients and a posterior-stabilised implant in 5 patients. No hinged implants were used. In 4 patients, internal fixation of the FO was performed. Mean follow-up was 10 years (range, 4-15 years). From baseline to last follow-up, the mean IKS score increased from 46 to 161 and mean flexion from 95° (range, 70-110°) to 107° (range, 90-120°). The HKA measured radiographically was between 178° and 182° in all 6 patients. The complications consisted of deep vein thrombosis in 1 patient and knee stiffness requiring manipulation under general anaesthesia in 1 patient. No patient experienced mal-union or required revision surgery. DISCUSSION: Apart from a case-series study of 11 patients, very few data are available on 1S-TKA-FO. In our small population, no major complications were recorded. The encouraging long-term outcomes warrant a recommendation to perform 1S-TKA-FO in patients with knee osteoarthritis and an intra-femoral deformity greater than 10°. LEVEL OF EVIDENCE: IV, prospective observational cohort study.

Same-stage total knee arthroplasty and osteotomy for osteoarthritis with extra-articular deformity. Part I: Tibial osteotomy, prospective study of 26 cases.

BACKGROUND: In patients with advanced knee osteoarthritis and extra-articular knee deformity (EKD), ligament balance may be difficult to achieve during total knee arthroplasty (TKA). Treatment options include two-stage surgery with the first stage involving correction of the EKD and same-stage TKA and tibial osteotomy (1S-TKA-TO). The objective of this study was to assess outcomes in 26 patients managed with 1S-TKA-TO. HYPOTHESIS: 1S-TKA-TO produces satisfactory clinical and anatomical outcomes and is not associated with higher morbidity rates compared to TKA alone or two-stage TKA-TO. MATERIAL AND METHODS: A prospective study was conducted in 25 patients (26 knees) managed with 1S-TKA-TO between 1995 and 2014. There were 16 males and 9 females with a mean age of 64 years (range, 29-80 years) and a mean body mass index of 29.6 (range, 24-49). The EKD was constitutional in 14 knees, post-traumatic in 5 knees, and induced by TO in 7 knees. None of the patients received a hinged knee implant. In each patient, the clinical International Knee Society (IKS score) was assessed and the hip-knee-ankle angle (HKA), tibial mechanical angle (TMA), and femoral mechanical angle (FMA) were measured on radiographs before surgery and at last follow-up. RESULTS: The mean IKS score increased significantly, from 70 before surgery to 170 at the end of the mean 9-year follow-up. Mean flexion range increased from 98° to 107°. The clinical and anatomical outcomes were satisfactory in 25 patients. In the remaining patient, who had a history of multiple surgeries for Blount disease and a body mass index of 49, a severe complication consisting in massive skin necrosis followed by infection occurred; this was the only patient who required revision surgery with implant removal. DISCUSSION: These findings are consistent with the satisfactory outcomes observed in earlier studies, most of which included small numbers of patients. The alternatives to 1S-TKA-TO are under evaluation. The best indication for 1S-TKA-TO may be knee osteoarthritis with a greater than 10° intra-osseous deformity. LEVEL OF EVIDENCE: IV, prospective observational cohort study.

Comparison of custom cutting guides based on three-dimensional computerized CT-scan planning and a conventional ancillary system based on two-dimensional planning in total knee arthroplasty: a randomized controlled trial.

PURPOSE: Incorrect positioning of components during total knee arthroplasty (TKA) increases the risk of pain, instability, and early revision. The purpose of this study was to compare 3D planning-assisted and a conventional system for TKA positioning. We hypothesized that the use of three-dimensional CT-scan planning and custom cutting guides would increase the accuracy of component positioning. METHODS: A randomized, controlled, prospective study of two groups was performed. In one group, patient-specific custom cutting guides (PSCG) were used for component positioning based on 3D CT-scan planning. In the control group, TKA was performed with a conventional ancillary system. The components' positioning angles were measured on 3D reconstructions. The main evaluation criterion was the percentage of outliers outside of a target zone of ± 3° for the coronal positioning of the femoral component. RESULTS: Eighty patients were included. The percentage of outliers for the femoral component was significantly lower in the 3D-guided group (1 patient) compared to the control group (7 patients p = 0.02). The coronal femoral angle was restored with greater accuracy in the 3D-assisted group (- 0.1° ± 1.4°) compared to the control group (1.6° ± 2.5°). Surgery was significantly shorter in the 3D group. The clinical outcomes were better in the 3D group at the two year follow-up with fewer failures and a lower standard deviation in IKS scores. CONCLUSION: The use of a 3D planning and custom guides can improve TKA component positioning by increasing the accuracy of implants alignment and reducing the percentage of outliers. The same benefit was not demonstrated for the global knee alignment and the clinical scores with no indisputable clinical advantage for the PSCG.

Three-dimensional planning-guided total hip arthroplasty through a minimally invasive direct anterior approach. Clinical outcomes at five years' follow-up.

PURPOSE: The direct anterior approach is an attractive option for total hip arthroplasty (THA) in order to achieve a quicker rehabilitation. However, this surgical technique presents a longer learning curve and a higher complications rate compared with the standard approach. We investigated whether three-dimensional (3D) planning anticipated the surgical difficulties and helped to achieve a low complications rate with respect to intra-operative complications, dislocation risk and lower limb discrepancy (LLD). METHODS: One hundred and fifty-four consecutive patients underwent a primary cementless THA using a direct anterior approach. A 3D planning was performed in order to anticipate the difficulties that may be encountered regarding femur perforation or fracture, dislocation and LLD. All patients were assessed at a mean five years' follow-up. RESULTS: No false route and no fracture occurred at the time of surgery. All the surgical difficulties were anticipated. A motorised reaming procedure of the femur was required in six patients because of a very dense bone or a narrow femur. A retroverted neck was used in 7 % of patients because of a torsional abnormality and enabled an increase in stability. The real implant sizes were the same as the ones planned in 97 % for the cup, 96 % for the stem and 100 % for the neck. At five years' follow-up, no dislocation occurred, no patient complained about LLD and excellent clinical outcomes were achieved. CONCLUSIONS: This study demonstrates that 3D pre-operative planning-guided THA through a minimally invasive direct anterior approach is a safe and accurate procedure. LEVEL OF EVIDENCE: Level IV.

Comparison of Three-Dimensional Planning-Assisted and Conventional Acetabular Cup Positioning in Total Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: Malpositioning of the acetabular cup during total hip arthroplasty increases the risk of dislocation, edge-loading, squeaking, early wear, and loosening. We hypothesized that the use of three-dimensional (3-D) visualization tools to identify the planned cup position relative to the acetabular edge intraoperatively would increase the accuracy of cup orientation. The purpose of this study was to compare 3-D planning-assisted implantation and freehand insertion of the acetabular cup. METHODS: This was a prospective randomized controlled study of two groups of twenty-eight patients each. In the first group, cup positioning was guided by 3-D views of the cup within the acetabulum obtained during 3-D preoperative planning. In the control group, the cup was placed freehand. All of the patients were operated on by the same surgeon, through a minimally invasive direct anterior approach with the patient in the supine position. Cup anteversion and abduction angles were measured on 3-D computed tomography (CT) reconstructions. The main evaluation criterion was the percentage of outliers according to the Lewinnek safe zone. RESULTS: Operative time did not differ between the two groups. The cup anteversion was more accurate in the 3-D planning group (mean difference from the planned angle [and standard deviation], -2.7° ± 5.4°) compared with the freehand-placement group (6.6° ± 9.5°). According to the Lewinnek safe zone, overall, the percentage of outliers was lower in the 3-D planning group (21%; six patients) than in the control group (46%; thirteen patients). According to the Callanan safe zone, the percentage of outliers was also lower in the 3-D planning group (25% versus 64%). Although cup abduction was also restored with greater accuracy in the 3-D planning group, on the basis of the Lewinnek safe zone, the percentage of abduction outliers was comparable between groups, with fewer high-abduction values, but more low-abduction values, in the 3-D planning group. CONCLUSIONS: Preoperative 3-D planning increased the accuracy of anteversion restoration and reduced the percentage of outliers without increasing the operative time. In this study, the same advantage could not be demonstrated for abduction. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Evaluation of spinal cord compression and hyperintense intramedullary lesions on T2-weighted sequences in patients with cervical spondylotic myelopathy using flexion-extension MRI protocol.

BACKGROUND CONTEXT: Acquired cervical stenosis is caused by the combination of disc protrusion, facet joint degeneration, hypertrophy of the ligamentum flavum, and osteophyte formation. Although these mechanical factors seem to play an important role in the pathogenesis of myelopathy, the role of dynamic factors has been suggested by many authors. Based on these results, dynamic magnetic resonance imaging (MRI) was proposed to improve diagnostic techniques in patients with cervical myelopathy. PURPOSE: The purpose of the study was to evaluate the importance of dynamic MRI in the assessment of cervical canal stenosis and to determine the percentage of levels in which cord impingement was only visible in the extension MRI and the percentage of cases in which hyperintense intramedullary lesions (HILs) were identified only on the flexion MRI. STUDY DESIGN: This is a retrospective case series study. PATIENT SAMPLE: Patients with spondylotic myelopathy who had dynamic cervical MRI at our department from October 2005 to February 2007 were included. MATERIALS AND METHODS: Fifty-one consecutive patients with spondylotic myelopathy had MRI in the neutral, flexion, and extension positions of the cervical spine. OUTCOME MEASURES: The following entities were evaluated: canal stenosis (the evaluation of the stenosis was based on the Muhle classification) and the presence or absence of HILs. RESULTS: Two hundred fifty-five levels were evaluated in the three positions. At each level, the stages in extension were higher than the stages in neutral and flexion positions (p<.05). From C3 to C6, around 22.5% of Stage 3 levels in the extension were Stage 1 in the neutral position. In flexion, HILs are better identified than in neutral and extension positions (p<.05). In 10% of the patients, HILs were identified only in the flexion T2-weighted sequence. CONCLUSIONS: Extension MRI helps to identify significant cervical canal stenosis that is partially or completely absent on neutral and flexion MRI and to determine the exact number of levels to decompress surgically. Flexion MRI permits better visualization of HILs on T2-weighted sequences.

Treatment of habitual patellar dislocation in an adult by isolated medial patellofemoral ligament reconstruction.

Habitual patellar dislocations are rare in adults. Treatment is difficult, and often associated with significant morbidity. A 30-year-old man, construction worker, presented a habitual patellofemoral dislocation which was caused by direct trauma to the knee as a child. Clinical examination showed a 3 cm leg-length discrepancy with no rotational deformities. The patient had a limp and loss of function; the patella was dislocated laterally and had locked at 20° of flexion with a range of motion of 0°/0°/30°. Open surgery was performed associating lateral retinacular release, reconstruction of the medial patellofemoral ligament with an ipsilateral gracilis tendon graft. The postoperative course was simple with no complications. Four months after surgery the patient has begun working normally. At the final 50-month clinical follow-up, knee range of motion was 0°/0°/130°, and functional results were excellent on clinical assessment scores of Kujala, Lysholm, and subjective IKDC. MPFL reconstruction alone seems effective in habitual posttraumatic patellar dislocation in adults without any associated bone anomalies.

Sacropelvic fixation with iliosacral screws: applications and results in adult spinal deformities.

STUDY DESIGN: Retrospective radiographic and clinical review. OBJECTIVE: To determine the feasibility of iliosacral screw fixation in adult spinal deformations. SUMMARY OF BACKGROUND DATA: Pelvic fixation is one of the most challenging instrumentation problems. The poor bone quality frequently found within the sacrum and the large lumbosacral loads with cantilever pullout forces across this region explain its frequent failure. METHODS: Fourteen adult patients undergoing pelvic fixation using iliosacral screws with a minimal follow-up of 24 months were analyzed for radiographic outcomes. Radiographic data included the localization of the spinal deformity, the Cobb angle, T4-T12 thoracic kyphosis, L1-S1 lumbar lordosis, the T9 tilt, the pelvic parameters, and the POA. Mechanical and infectious complications were also noted. RESULTS: The lumbo-pelvic correction was performed with a large reduction of the POA in every case. The frontal and sagittal corrections obtained with this procedure were considered as being effective. There were no mechanical complications due to failure of the instrumentation, loss of sacral fixation, or loss of lumbar lordosis at the time of the last follow-up. One patient experienced local infection on the left iliosacral screw without any residual functional sequel. DISCUSSION: Iliosacral screwing can offer a pelvic fixation reliable enough to allow restoration of 3-dimensional trunk balance. This technique has a quite short learning curve and adequately permits frontal and sagittal corrections, increases stability, and decreases instrumentation-related complications. Our observations suggest that it is applicable to pelvic fixation in adult surgery.

High 10-year survival rate with an anatomic cementless stem (SPS).

BACKGROUND: Proximal cementless fixation using anatomic stems reportedly increases femoral fit and avoids stress-shielding. However, thigh pain was reported with the early stem designs. Therefore, a new anatomic cementless stem design was based on an average three-dimensional metaphyseal femoral shape. However, it is unclear whether this stem reduces the incidence of thigh pain. QUESTIONS/PURPOSES: We asked whether this stem design was associated with a low incidence of thigh pain and provided durable fixation and high function. METHODS: One hundred seventy-one patients (176 THAs) who had the anatomic proximal hydroxyapatite-coated stem implanted were reviewed. Eleven (6%) patients were lost to followup and 34 (20%) died without revision surgery. We used the Harris hip score (HHS) to assess pain and function. We evaluated femoral stem fixation and stability with the score of Engh et al. and also calculated a 10-year survival analysis. We assessed 126 patients (131 hips) at a mean followup of 10 years (range, 8-11 years) RESULTS: At last followup, two patients described slight thigh pain that did not limit their physical activities. All stems appeared radiographically stable and one stem was graded nonintegrated but stable. Five patients had revision surgery: one on the femoral side (for posttraumatic fracture) and four on the acetabular side. Considering stem revision for aseptic loosening as the end point, survivorship was 100% (range, 95.4%-99.9%) at 10 years. CONCLUSION: This anatomic cementless design using only metaphyseal fixation with a wide mediolateral flare, a sagittal curvature, and torsion, allowed durable proximal stem stability and fixation.

Preoperative evaluation of the cervical spondylotic myelopathy with flexion-extension magnetic resonance imaging: about a prospective study of fifty patients.

STUDY DESIGN: The authors evaluated preoperative modifications of the cervical spinal canal in flexion and extension in 50 patients with cervical spondylotic myelopathy (CSM) and looked for impingement of the spinal cord not diagnosed in the neutral position. OBJECTIVE: To evaluate the usefulness of preoperative flexion-extension magnetic resonance imaging (MRI) for patients with CSM. SUMMARY OF BACKGROUND DATA: Dynamic factors contribute to CSM. Although the clinical manifestations and spinal or spinal cord morphology in patients with myelopathy have been reported, to our knowledge, there are no studies that include the cervical spinal cord length, sagittal diameter, and available space in patients with CSM in flexion, extension, and the neutral position. METHODS: Dynamic MRI changes in canal stenosis during flexion-extension were evaluated in 50 patients with CSM in the supine position. The authors determined length of the cervical cord (LCC, C1-C7), cervical cord sagittal diameter (CCSD, C3-T1), cervical cord available space (CCAS, C3-T1), intramedullary high-intensity signal (IHIS) changes, number of stenosis, and severity of cord impingement in flexion, extension, and the neutral positions. RESULTS: On both the anterior and posterior edges of the cord, mean LCC in flexion was longer than in extension or the neutral position and longer in the neutral position than in extension (P < 0.05). In all three positions, the average length of the anterior edge of the cervical cord was longer than the posterior edge (P < 0.05). The mean value of CCSD at each level in extension was greater than in flexion or the neutral position (P < 0.05). In the neutral position, CCSDs were greater than in flexion from C4 to C7 (P < 0.05), but this difference failed to reach significance at levels C3 and T1. In the neutral position, CCAS was greater than in either extension or flexion (P < 0.05), and CCAS was greater in flexion than in extension (P < 0.05) at all levels except C6, at which CCAS was greater in flexion than in either extension or the neutral position (P < 0.05). MRI demonstrated functional cord impingement (grade 3 of Mühle) in 6 of the 50 (12%) patients in flexion, in 17 patients (34%) in the neutral position, and in 37 patients (74%) in extension. IHIS was observed in flexion in 20 patients (40%), in the neutral position in 13 patients (26%), and in extension in 7 patients (14%). CONCLUSION: Cervical spondylotic myelopathy results from the synergistic action of static and dynamic factors, the latter of which play an important role. In some patients, IHIS on T2 images is only visible with the neck in flexion. That might explain why IHIS is first detected after surgery in some patients in whom MRI was obtained before surgery only in the neutral position. Dynamic MRI is useful to determine more accurately the number of levels where the spinal cord is compromised, and to better evaluate narrowing of the canal and IHIS. New information provided by flexion-extension MRI might change our strategy for CSM management.

Acetabular anteversion with CT in supine, simulated standing, and sitting positions in a THA patient population.

BACKGROUND: Appraisal of the orientation of implants in THA dislocations currently is based on imaging done with the patient in the supine position. However, dislocation occurs in standing or sitting positions. Whether measured anteversion differs in images projected in the position of dislocation is unclear. QUESTIONS/PURPOSES: We compared measured acetabular cup orientations on axial CT scans taken with the patient in a supine position with those from CT sections at angles to the sacral slope reflecting standing and sitting positions. METHODS: We retrospectively reviewed the radiographs of 328 asymptomatic patients who had THAs. Anatomic acetabular anteversion (AAA) was measured from the plain CT scan (supine position, axial CT sections). The AAA also was measured on reformatted CT scans in which the orientation was adjusted individually to the sacral slope on lateral radiographs with patients in the standing and sitting positions. RESULTS: The mean/(SD) AAA changed from 24.2° (6.9°) in the supine position to 31.7° (5.6°) and 38.8° (5.4°) in simulated standing and sitting positions, respectively. The supine AAA correlated with the standing AAA (r = 0.857) but not with the sitting AAA (r = 0.484). CONCLUSIONS: These data suggest measurement of the AAA on a plain CT scan used in current practice is biased. In patients with recurrent posterior dislocation from a sitting position, accounting for the functional variations in measurement of the position of the acetabular cup provides more relevant information regarding component positioning.

Shortening osteotomy and sacro-sacral fixation for U-shaped sacral fractures.

STUDY DESIGN: Technical note and retrospective first cases study. OBJECTIVE: To present a novel surgical procedure for treating rare and challenging U-shaped fractures of the sacrum. SUMMARY OF BACKGROUND DATA: U-shaped fractures of the sacrum are not frequent and usually seen in the context of high energy trauma (high-fall injury). There is no consensus about the therapeutic strategy. When surgery is decided on selected patients, the technique raises several issues for the neural decompression, reduction, and fixation. The L5-S1 mobility has to be sacrificed for most authors. METHODS: Based on anatomic considerations, the authors present here the original surgical technique they have been using at their institution and a consecutive series of patients. The procedure associates a shortening osteotomy of the sacrum at the site of the fracture and a sacro-sacral fixation. RESULTS: The proposed procedure was simple, safe, and effective. CONCLUSIONS: Performing the osteotomy helps in the reduction and allows a short fixation, which spares the mobility of the lumbo-sacral junction.

Modification of pelvic orientation after total hip replacement in primary osteoarthritis.

The acetabular anteversion angle varies according to the position of the pelvis. The objective goal of our study was to investigate changes in pelvic orientation after total hip replacement for primary osteoarthritis. We studied 89 patients who underwent total hip replacement for primary unilateral osteoarthritis. Lateral pelvic X-rays that included the hips were performed pre-operatively and one year post-operatively. Reference values were calculated by carrying out the same analysis in 100 asymptomatic healthy volunteers. Pelvic orientation was analyzed using the sacral slope. Patients having surgery for osteoarthritis had a decreased pelvic range of motion pre-operatively and post-operatively when compared to healthy volunteers. Post-operatively, this range of motion increased by 3 degrees but remained lower than the norm. Compared to asymptomatic healthy volunteers, patients affected by osteoarthritis had a posterior pelvic extension that decreased post-operatively but did not return to norm. This post-operative pelvic inclination generates a significant decrease in the final cup anteversion and thus may predispose to posterior dislocation. As this post-operative alteration to pelvic orientation cannot be anticipated, computer-aided surgery for cup positioning may not improve the accuracy of the acetabular anteversion in some patients.

Outcome and serum ion determination up to 11 years after implantation of a cemented metal-on-metal hip prosthesis.

BACKGROUND AND PURPOSE: Little is known about the long-term outcome of cemented metal-on-metal hip arthroplasties. We evaluated a consecutive series of metal-on-metal polyethylene-backed cemented hip arthroplasties implanted in patients under 60 years of age. METHODS: 109 patients (134 joint replacements) were followed prospectively for mean 9 (7-11) years. The evaluation included clinical score, radiographic assessment, and blood sampling for ion level determination. RESULTS: At the final review, 12 hips had been revised, mainly because of aseptic loosening of the socket. Using revision for aseptic loosening as the endpoint, the survival rate at 9 years was 91% for the cup and 99% for the stem. In addition, 35 hips showed radiolucent lines at the bone-cement interface of the acetabulum and some were associated with osteolysis. The median serum cobalt and chromium levels were relatively constant over time, and were much higher than the detection level throughout the study period. The cobalt level was 1.5 microg/L 1 year after implantation, and 1.44 microg/L 9 years after implantation. INTERPRETATION: Revisions for aseptic loosening and radiographic findings in the sockets led us to halt metal-on-metal-backed polyethylene cemented hip arthroplasty procedures. If the rigidity of the cemented socket is a reason for loosening, excessive release of metal ions and particles may be involved. Further investigations are required to confirm this hypothesis and to determine whether subluxation, microseparation, and hypersensitivity also play a role.

Mathematical evaluation of jumping distance in total hip arthroplasty: influence of abduction angle, femoral head offset, and head diameter.

BACKGROUND AND PURPOSE: The jumping distance (JD) is the degree of lateral translation of the femoral head center required before dislocation occurs. The smaller the distance, the higher the theoretical risk of dislocation. The aim of our study was to evaluate this jumping distance and its variation according to the characteristics of the implant, and also the theoretical gain in using large head diameters of above 38 mm. METHODS: The JD was calculated as a function of the cup anteversion and abduction angles, the head diameter, and the head offset (defined as the distance between the center of the femoral head and the cup opening plane). Head diameters of 28, 32, 36, 40, 44 and 48 mm were analyzed. The abduction angle was increased from 0 degrees to 80 degrees with a 10 degree increment. The anteversion angle was increased from 0 degrees to 40 degrees with a 5 degree increment. RESULTS: The jumping distance was found to decrease as the cup abduction angle increased (0.25 mm each 1 degree for 32-mm head diameter). It increased by 0.05 mm for a 1 degree increase in the anteversion angle. The jumping distance increased as the head diameter increased (0.4 mm each mm diameter for a 45 degree abduction angle). The net gain obtained by increasing the diameter, however, decreased when abduction angle increased (0.25 each mm diameter for 60 degree abduction). The JD decreased by 0.92 mm for each 1-mm increase in head offset, showing that head offset was the most important parameter influencing the JD. INTERPRETATION: The theoretical gain in stability obtained by using a large femoral head (above 36 mm) is negligible in cases where there is a high cup abduction angle. An increase in offset of the femoral head substantially reduces the jumping distance and it should therefore be avoided.

Clinical and biological assessment of cemented titanium femoral stems: an 11-year experience.

This study prospectively assessed the outcome of 134 cemented titanium stems and serum ion levels. The stems were polished (0.1 microm Ra) with circular cross section. At the end point, only one stem revision was performed for aseptic loosening, and two were planned due to subsidence greater than 5 mm. Non-progressive radiolucencies in zones 1 and 7 were observed in 16 hips at the cement-bone interface without osteolysis. Median serum titanium concentrations were below the detection limit (30 nmol/l) except in patients with failed stems. The overall stem survival rate was 97.7% at nine years, which is comparable to other series of cemented stems. The protective layer of titanium oxide coating the stem and a thick cement mantle may help resist aseptic loosening. In addition, satisfactory monitoring of the stem was reached using titanium serum level determination.

Optimization of total hip arthroplasty implantation: is the anterior pelvic plane concept valid?

The anterior pelvic plane (APP) is currently used as superficial anatomical landmark for three-dimensional orientation during total hip arthroplasty (THA), specifically when using computer aided surgery. However, the actual parameter for characterizing the pelvic orientation is the sacral slope, which correlates with other functional spinal parameters. The goal of the paper was to investigate relationships between APP and sacral slope. Both were measured on 328 lateral radiographs of the pelvis in standing position by two observers. The poor correlation between APP and sacral slope suggest keeping using the reference to the APP for the per-operative orientation in the 3D space, while individually adjusting the preoperative planning to the sacral slope.

Early mechanical failure in total knee arthroplasty.

Early mechanical dysfunction of a total knee arthroplasty (TKA) is a challenging problem in terms of causality and solutions. The current strategy in our department is to perform a complete TKA revision rather than the less invasive partial procedures when a clear mechanical cause of failure has been found. In this investigation, we assessed 21 patients who underwent complete TKA revision in 2003-2004 in our institution within the first two years following the index TKA. Various clinical presentations included pain, stiffness, instability, and femoro-patellar signs. These corresponded to implant size, position, and fixation issues. The IKS knee score/function significantly increased from 47/47 to 85/78 at follow-up (six months minimum). Compared to the data in the literature, this systematic full revision seems to be a reasonable approach. This attitude takes advantage of the modularity of the implants for allowing perioperative adjustments of position, fixation, and constraint. Based on the results of our study, we propose a list of six mechanical pitfalls to be evaluated in the case of early dysfunction: frontal misalignment, sagittal overstuffing or malpositioning, axial malrotation, poor bone fixation, inappropriate constraint or ligamentous balance, and inappropriate level of the joint space.