One-stage computer-assisted total knee arthroplasty and tibial osteotomy.

Same-stage tibial osteotomy may deserve consideration in candidates to total knee arthroplasty (TKA) who have severe bone deformities, particularly at extra-articular sites. This strategy obviates the need for either a major and technically difficult ligament release procedure, which may compromise ligament balancing, or the use of a semi-constrained prosthesis. This technical note describes a one-stage, computer-assisted technique consisting in TKA, followed by corrective tibial osteotomy to obtain an overall mechanical axis close to 180° without extensive ligament balancing. This technique provided satisfactory outcomes in 8 patients followed-up for at least 3years, with no specific complications or ligament instability and with a hip-knee-ankle angle close to 180°. After planning, intra-operative computer assistance ensures accurate determination of both implant position and the degree of correction achieved by the osteotomy.

Outcomes of 447 SCORE® highly congruent mobile-bearing total knee arthroplasties after 5-10 years follow-up.

INTRODUCTION: The goal of mobile-bearing total knee arthroplasties (TKA) with an anatomical trochlea is to reduce polyethylene wear, the risk of loosening, and patellofemoral complications. Rotating mobile-bearing SCORE(®) TKA was designed according to these principles with standard instrumentation for component placement and a specific computer navigation system, Amplivision(®). HYPOTHESIS: We hypothesized that the results of SCORE(®) TKA would be satisfactory and better using computer navigation with or without patellar resurfacing and that there would be no specific patellofemoral complications associated with this trochlear design. MATERIALS AND METHODS: Four hundred and forty-seven SCORE(®) TKA were performed. Outcome assessment was based on the IKS score, and component survival calculated by Kaplan-Meier analysis. RESULTS: Mean follow-up was 6.6 years (maximum 10.6 years). Six percent of patients were lost to follow-up. Ninety-eight percent of the patients were satisfied or very satisfied. The IKS knee score was 89 points and the function score was 86. The mechanical axis was 180° (174-186), and it was significantly improved if the initial deformity was severe and TKA was computer navigated. There were nine revisions (one for fracture, two for pain, two for stiffness, four for infection). DISCUSSION: This study confirmed our hypothesis: the results of SCORE(®) TKA were very satisfying after at least 5 years of follow-up because there was no mechanical loosening, no bearing dislocation and no patellofemoral complications with or without patellar resurfacing. Results were identical whether patellar resurfacing was performed or not. Although clinical results were not better for computer- navigated TKA, radiological results were. At 98 months of follow-up, component survival in relation to the risk of aseptic loosening or patellofemoral complications was 100%. LEVEL OF EVIDENCE: Level IV continuous retrospective study.

Computer-navigated revision total knee arthroplasty for failed unicompartmental knee arthroplasty.

The most frequent technical difficulty encountered at unicompartmental knee arthroplasty (UKA) revision to total knee arthroplasty (TKA) is filling in all bone defects. These bone defects can render difficult components positioning, mechanical axis restitution, and ligament balance assessment, which are the three most important parameters for successful TKA. We describe a computer-assisted technique which makes it possible to control these three parameters before removal of the implants that have caused the bone defects. Our study is based on a series of 20 cases, with a minimum follow-up of 2 years. The anatomical and clinical results were very satisfying and comparable to results of primary TKA. We recommend this computer-navigated technique, which is as simple as a primary TKA procedure.

[Revision total knee arthroplasty after unicompartmental femorotibial prosthesis: 54 cases]. / Reprise de prothèse unicompartimentale fémorotibiale par prothèse totale du genou. Résultats d'une série de 54 cas.

PURPOSE OF THE STUDY: We analyzed technical difficulties encountered when performing revision total knee arthroplasty in patients with unicompartmental femorotibial prostheses. MATERIAL AND METHODS: This multicentric retrospective study included 54 revisions of unicompartmental femorotibial prosthesis with implantation of a total knee prosthesis. The series included 45 medial and nine lateral compartment prostheses. A gliding total knee prosthesis was implanted in 53 cases (98%) (39 standard, 14 revision). Mean time to failure of the unicompartmental prosthesis was four years. IKS scores were established at review. The radiological work-up included AP and lateral views in single leg stance and goniometry for 22 medial compartment revisions. Twenty-seven patients were seen for physical examination and x-rays and eight were lost to follow-up; data were recorded from medical files for 19 patients. RESULTS: The revision procedure was considered easy in 82% of the cases. Mean follow-up after revision was four years (range 2 - 12 years). Subjective outcome was very satisfactory for 56% of the patients, satisfactory for 36% and unsatisfactory for 8%. The mean function score was 62 points, the mean knee score 85 points, and the mean flexion was 113 degrees. No laxity was found for 90% of the knees. The femorotibial angle was 180 +/- 2 degrees in 46% of the patients. The mechanical femoral angle was 90 degrees in 54% of the patients with 2-4 degrees varus in 42%. The mechanical tibial angle was 90 degrees in 46% of the patients with 2-8 degrees valgus in 37%. Complications included pulmonary embolism (n=2), mobilization under general anesthesia (n=3), arthrolysis (n=1), lateral vertical patellectomy (n=1), and secondary infection (n=1). There were five failures requiring changing the total knee prosthesis. DISCUSSION: Loss of bone stock raises specific problems during revision of unicompartmental knee prostheses. Loss of tibial bone is more frequent but it is more difficult to correct for loss of femoral bone. A gliding knee prosthesis is generally preferred for first intention revision. We recommend a long stem when the bone defect is important or involves loss of cortical bone. We have had good mid-term results with revision total knee prostheses after unicompartmental prostheses. Longer follow-up is needed. Poor results were obtained when revision was performed for persistent pain without a clearly defined cause. The presence or not of significant bone loss did not appear to affect outcome. The observation of medial laxity in case of failed lateral unicompartmental prostheses suggests a more constrained total knee prosthesis might be indicated. Compared with earlier series, our results with total knee prostheses after unicompartmental prostheses appear to be better than after tibial valgus osteotomy and also better than after total knee arthroplasty. Conversely, they would be less satisfactory than for primary total knee arthroplasty. The surgical procedure for revision total knee arthroplasty after unicompartmental prosthesis requires precision and skill but is not technically difficult.

A comparative study of medial versus lateral arthroscopic partial meniscectomy on stable knees: 10-year minimum follow-up.

PURPOSE: Our goal was to compare results of partial medial arthroscopic meniscectomy with results of partial lateral arthroscopic meniscectomy and to determine prognostic factors. TYPE OF STUDY: Retrospective comparative study with statistical analysis. METHODS: In this study, 362 medial and 109 lateral isolated arthroscopic meniscectomies are presented with a minimum follow-up time of 10 years. All knees were stable with no previous surgery or traumatic lesion. RESULTS: In this study, 95% of the patients were very satisfied or satisfied with the results of the medial meniscectomy, and 95.5% with results of the lateral meniscectomy (P =.32). According to grades 1 and 2 of the International Knee Documentation Committee (IKDC) form, 85.8% of the medial meniscectomy group were free of any symptoms, as were 79.7% of the lateral meniscectomy group (P =.11). Radiologic changes after medial and lateral meniscectomy were found in 21.5% and 37.5%, respectively (P =.11). The rates of radiologic changes in patients in whom the contralateral knee was radiologically normal were 22.3% and 39%, respectively (P =.016). The rate of repeat surgeries for osteoarthritis was less than 0.2%. CONCLUSIONS: Subjective and clinical results after medial or lateral meniscectomy are quite similar, but radiologic results are significantly worse after lateral meniscectomy. The most accurate way to determine the degeneration caused by the meniscectomy is to evaluate joint space narrowing in patients in whom the contralateral knee was radiologically normal. Otherwise, partial medial or lateral meniscectomy are well tolerated. A better prognosis can be predicted for a patient with an isolated medial meniscal tear with one or more of the following factors: age less than 35 years, a vertical tear, no cartilage damage, and an intact meniscal rim at the end of the meniscectomy. With an isolated lateral meniscal tear, a better prognosis can be predicted if the patient is young and has an intact meniscal rim at the end of the meniscectomy.

[Influence of the height of the joint space on the three-dimensional kinetics of total knee prostheses and behavior of the lateral ligaments: an in vitro study]. / Influence de la hauteur de l'interligne articulaire sur la cinématique tridimensionnelle du genou prothésé et sur le comportement des ligaments collatéraux: analyse in vitro.

PURPOSE OF THE STUDY: The level of the joint space can be modified after implantation of a total knee prosthesis. Likewise, ligament balance is a cardinal point of the surgical technique. The purpose of this in vitro work was to study the influence of the position of the distal tibiofemoral joint space after implantation of a total knee prosthesis on the three-dimensional kinetics of the knee joint and on the behavior of the lateral ligaments. MATERIAL AND METHOD: Total knee arthroplasty (TKA) with a posterior stabilized prosthesis was performed on seven fresh-frozen cadaver specimens. A specially-designed experimental device was used to achieve continuous knee motion simulating hip flexion from a vertical position. The Vicon optoelectronic system was used to record the femorotibial and femoropatellar kinematics in three dimensions. Two electronic goniometers were positioned on the insertions of the lateral ligaments to measure ligament displacements during knee movements. Five configurations were recorded on each knee: healthy knee, same knee after TKA, and 2-mm and 4-mm upward displacement of the prosthetic distal tibiofemoral joint space. Ligament balance at extension was preserved in all configurations. The kinematic curves obtained were compared with the coefficient of multiple correlation. RESULTS: Changing the position of the joint space had a significant effect on the kinematics of the patella (rotation and abduction-rotation) but did not have a significant effect on the femorotibial kinematics. Variations in the length of the lateral ligaments were of small amplitude. Lowering the joint space led to laxity at flexion. Raising the joint space tightened the ligaments at flexion. DISCUSSION: These results confirm our clinical impression when the level of the distal femur cut is set to achieve tension on the ligaments at knee extension. If the joint space is lowered, i.e. with a more sparing distal femur cut, the prosthesis takes up less space during flexion, leading to laxity at flexion. If the joint space is raised, i.e. with an excessive distal femur cut, the prosthesis takes up more space during flexion, tightening the lateral ligaments. CONCLUSION: The position of the joint space must be rigorously reproduced during TKA not only to maintain correct femorotibial kinematics, but most importantly to preserve patellar kinematics and proper behavior of the lateral ligaments. Ideally, the height of the joint space should be restored first, followed by control of the ligament balance. An over- or undercut of the femur can lead to defective femoropatellar kinematics and ligament tension at flexion despite good ligament balance at extension. In addition, ligament balance should not be achieved by displacing the tibial cut or by modifying the thickness of the tibial component, which would have an effect not only at extension but also at flexion.

[Arthroscopic reconstruction of the anterior cruciate ligament]. / Greffe isolée du ligament croisé antérieur sous contrôle arthroscopique avec un transplant os-tendon-os.

PURPOSE OF THE STUDY: We report a retrospective series of 83 patients (86 knees) who underwent reconstruction surgery for chronic anterior knee laxity. The purpose of this study was to analyze mid-term results and assess prognosis factors. MATERIAL AND METHODS: All patients underwent artrhoscopic reconstruction of the anterior cruciate ligament using a central one-third patellar tendon graft. Full follow-up data were available for 51 patients (52 knees) and partial data for 24 others (25 knees). Eight patients (9 knees) were lost to follow-up. The IKDC criteria were used to analyze outcome at a mean 6 years post-surgery. RESULTS: Graft failure was observed in 5 knees and a graft tears after a new sprain was seen at 3 years. The patients were satisfied or very satisfied in 88.5% of the cases. The Trillat-Lachman test revealed a persistent dampened brake in 5 knees and a frank click in 4 (7.7%). Complete movement was recovered in all knees excepting 2 exhibiting persistent flexion. Residual laxity (active Lachman test) was 5 mm in 81.5% of the cases, between 6 and 10 mm in 17%, and greater than 10 mm in only 1 case (2.5%). IKDC scores were A=25%, B=50%, C=21% and D=4%. Forty-two patients (61%) returned to their sports activities and 9 of the 12 high-level athletes resumed competition at the same level as preoperatively. Arthroscopy enabled a well- or very well-positioned femoral tunnel in 88% of the cases, conditioning final IKDC outcome (p<0.02). There was a correlation between the meniscal status and residual laxity. DISCUSSION: This study demonstrated a high proportion (21%) of patients with an incomplete repair (21% IKDC class C) with a residual laxity greater than 5 mm and a late hard brake. Simple patellar tendon graft provided insufficient repair of the anterior cruciate ligament. The subjective outcome was better than the objective outcome since 88.5% of the patients were satisfied or very satisfied (patients seen at last follow-up or contacted by telephone). Good objective outcome was correlated with good femoral position of the transplant and preservation of the meniscus. Failures were explained by poor position of the transplant, long-standing laxity, and renewal of sports activities too early. CONCLUSION: Arthroscopic repair of the anterior cruciate ligament is a reliable procedure, but as failures are observed, indications should take into consideration the type of laxity and the status of the meniscus. For unique anterior laxity, the central one-third patellar tendon graft gives good results. For advanced anterior laxity, augmentation with an extra-articular lateral tenodesis would be necessary.

The natural history of the knee following arthroscopic medial meniscectomy.

We examined the natural history of arthroscopic medial meniscectomy in knees with an isolated meniscal injury by reviewing 317 of 894 cases following medial meniscectomy. At the time of the initial surgery none of the knees had been operated on, and there was no evidence of ligament injury. The patients were reviewed clinically and radiologically after a mean of 11.5 years (range 10-15). The knee was considered "normal" or "nearly normal" by 91% of patients. In 218 patients the contralateral knee was asymptomatic without history of operation or significant injury and could be used as control for comparison. Radiology showed 22.4% greater excess prevalence of joint space narrowing in the operated compared to the control knee. The factors predisposing to a poor radiological result were age above 35 years, the presence of medial compartment cartilage degeneration at the time of the first arthroscopy, resection of the posterior one-third of the meniscus, and meniscal rim resection. Preoperative participation in sport was a predictor of a better outcome.