Standard Medial Parapatellar Approach Research Articles

Minimally invasive total knee arthroplasty using a cruciate-retaining knee system: A 3–5 year study with comparison to a standard approach

Background/PurposeMinimally invasive surgery (MIS) for total knee arthroplasty (TKA) is a recent development. Most published studies of the procedure report on early experience, and have emphasized early recovery and good outcomes in the first 3 months to 1 year. MethodsThis retrospective study compared 121 TKA done through a minimally invasive midvastus approach with 50 TKA done using a standard medial parapatellar approach, and assessed the results at a minimum follow-up of 3–5 years. A cemented U2 cruciate-retaining knee (United, Taipei, Taiwan) was used in both patient groups. ResultsThe postoperative mean knee score and function score were 95.3 (range, 69–110) and 82.3 (range, 20–100) respectively in the MIS TKA group, compared to 94 (range, 78–00) and 82 (range, 30–100) for the control group (standard approach). The postoperative Knee Society scores did not differ significantly between the two groups. The postoperative mean range of motion was 113.8° (range, 70–145°) in the MIS TKA group compared with 105.1° (range, 40–130°) for the control group, and the difference was significant (p < 0.05). There was no difference in postoperative coronal X-ray alignment between the two groups, neither were there any outliers in the component alignment and component size in the MIS TKA group. There were three knees (2%) with anterior femoral notching in the MIS TKA group compared to no knee notching for the control group. ConclusionThough the MIS TKA was technically demanding, the outcomes at 3–5 years’ follow-up were at least as good as those obtained with the standard medial parapatellar TKA procedure.

Measurement of knee joint gaps without bone resection: “Physiologic” extension and flexion gaps in total knee arthroplasty are asymmetric and unequal and anterior and posterior cruciate ligament resections produce different gap changes

General agreement is that flexion and extension gaps should be equal and symmetrical in total knee arthroplasty (TKA) procedures. However, comparisons using a standard TKA approach to normal knee joints that have not undergone bone resection are currently unavailable. Since bony preparation can influence capsule and ligament tension, our purpose was to perform measurements without this influence. Ten normal cadaveric knees were assessed using a standard medial parapatellar TKA approach with patellar subluxation. Gap measurements were carried out twice each alternating 100 and 200 N per compartment using a prototypical force-determining ligament balancer without the need for bony resection. Initial measurements were performed in extension, followed by 908 of flexion. The ACL was then resected, and finally the PCL was resected, and measurements were carried out in an analogous fashion. In general, the lateral compartment could be stretched further than the medial compartment, and the corresponding flexion gap values were significantly larger. ACL resection predominantly increased extension gaps, while PCL resection increased flexion gaps. Distraction force of 100 N per compartment appeared adequate; increasing to 200 N did not improve the results.

Comparison of the Minimally Invasive and Standard Medial Parapatellar Approaches for Total Knee Arthroplasty: Systematic Review and Meta-Analysis

This systematic literature review analysed the efficacy of minimally invasive subvastus (SV) and midvastus (MV) approaches, compared with the standard medial parapatellar (MP) approach, for total knee arthroplasty. Fixed- and random-effect meta-analyses were performed to pool the results of primary studies assessing the mean difference of each clinical outcome. Length of hospital stay was significantly different between the MP and SV approaches, but not between the MP and MV approaches. Blood loss was significantly higher following MP compared with SV. The number of days to perform a straight-leg raise was significantly longer following MP than either MV or SV. In the first 6 months postsurgery, MV was associated with a better range of motion (ROM) than MP. No significant difference in ROM between MP and SV was apparent at 1 year postsurgery. Quadriceps muscle strength recovered significantly more slowly following MP compared with SV. Future studies should assess the efficacy of the quadriceps-sparing approach and compare minimally invasive approaches, assessing intrinsic postoperative differences.

Subvastus and Medial Parapatellar Approaches in TKA: Comparison of Functional Results

The purpose of this study was to compare the clinical results of total knee arthroplasty (TKA) in the early and late postoperative period using subvastus and medial parapatellar approach. A prospective randomized controlled study was conducted in a group of 169 patients (180 TKAs) with 2-year follow-up. Patients were divided into a study group (97 TKAs) with a subvastus approach and a control group (83 TKAs) with a parapatellar approach. Assessment of the results of both operating approaches was based on functional, clinical Knee Society Score, and pain (visual analog scale). Patients in the subvastus group achieved full active extension, better range of motion, and better Knee Society Score results at 12 days, 6 weeks, and 12 weeks earlier than patients in the medial parapatellar group. They also had less pain at 12 days. No statistically significant differences existed between assessed end points in both groups at 24- and 52-weeks, and 24-months postoperatively. The subvastus approach has given patients better early clinical results; however, at longer follow-up, both groups had similar outcomes. The potential benefits of the subvastus approach are: protection of the extensor mechanism from damage, less risk of damaging the blood supply to the patella, earlier clinical recovery, and less pain in the early postoperative period. The subvastus approach is an alternative to the standard medial parapatellar approach in TKA. It can be used with equally good results, especially taking into consideration positive clinical aspects in the early postoperative period.

Total knee arthroplasty in severe valgus knee deformity: comparison of a standard medial parapatellar approach combined with tibial tubercle osteotomy

Primary TKA in valgus knees with a deformity of more than ten degrees may prove challenging, since bone and soft tissue abnormalities make accurate axis restoration, component orientation and joint stability attainment a difficult task. The purpose of this study was to determine which approach is optimal in these patients, by comparing the standard medial parapatellar approach to a lateral parapatellar combined with a tibial tubercle osteotomy (TTO). Forty-four valgus knees--with an axis deviation ranging from 15 to 36 degrees (mean 24°)--were dealt with primary TKA and followed up for a minimum period of 7 years. Lateral parapatellar arthrotomy combined with TTO was performed in 22 individuals (Group A) and a standard medial parapatellar capsulotomy in the remaining patients (Group B). The International Knee Society System Score (IKSS) was used for clinical evaluation. Radiological assessment was performed yearly postoperatively using long films for assessment of the anatomical axis. The postoperative IKSS scores showed no significant statistical difference between groups A and B (P < 0.05). In the alignment parameter, however, residual valgus deviation occurred in 9% of patients from Group A and in 32% from Group B. No late-onset instability was displayed. Lateral parapatellar approach combined with TTO may prove highly beneficial in significant valgus deformities, as the anatomical axis is restored accurately and soft tissue release of the lateral contracted structures facilitated to an important extent.

Development of a force-determining tensor to measure “physiologic knee ligament gaps” without bone resection using a total knee arthroplasty approach

BackgroundLigament balancing is a challenging but essential part of successful total knee arthroplasty. There is general agreement that flexion and extension gaps should be equal and symmetrical. However, to date there are no available comparisons to physiologically normal knee joints that have not undergone bone resection. There are also no standards specifying which instruments (e.g., spacers, distractors, trial components, navigation systems) and particularly what degree of force should be used for gap distraction. MethodsTo measure the physiological extension and flexion gaps, a prototypical force-determining tensor (Aesculap, Tuttlingen, Germany) was constructed and adapted so that force could be applied directly through Schanz screws inserted medially and laterally on the tibia and femur, independent of each other and without the need for bony resection. Ten normal cadaveric knees were assessed using a standard medial parapatellar total knee arthroplasty approach with patellar subluxation. Gap measurements were carried out twice, alternating distraction forces of 100 and 200N each time. ResultsThe prototype was implemented successfully. Repeat measurements showed only slight deviation from the original, resulting in minimal standard error. Precision did not vary with the application of greater force (200 N), but gap size increased significantly (p < 0.001). ConclusionsThe success of this assessment with cadaveric knees indicates that this prototype can be applied to measure flexion and extension gaps without the need for bony resection. Increasing the distraction force to 200N does not improve results, so 100N per compartment appears adequate. Most likely, the extension and flexion gaps are physiologically asymmetric and unequal, and the kinematics are markedly altered after resection of the PCL and/or ACL. This new force-determining tensor can be used for further analyses, e.g., to explore the effects of selective ligament resection.

Comments on Bonutti PM et al.: Minimally invasive total knee arthroplasty using the contralateral knee as a control group: a case-control study

Dear Editor, We read with interest the article by Bonutti et al. [1]. The authors believe that the results demonstrate superior outcomes in patients who had a total knee arthroplasty (TKA) with a minimal invasive surgery (MIS) approach compared to a standard medial parapatellar approach using the contralateral knee as a control group. This work shows the results of a MIS knee dedicated centre (with experience of 3,000 procedures of this technique). In our opinion these results could not be repeated in a general orthopaedic unit. First, we noticed that the surgical mean time is close to one hour, but other studies [2, 3] show a longer time to perform the MIS technique. The authors recommended this technique on the basis of the Knee Society system (KSS) score and the improvement of range of motion (ROM), but after a year of follow-up the differences are minimal or nonexistent in KSS and only 4o of difference in ROM. In a prospective and randomised study [4] that compares both techniques via functional scales, subjective impressions and opinions on quality of life, we have found that, although MIS has some advantages immediately postoperative (patient's well-being, hospital stay, analgesic use, etc.), the results are similar at six months, both in objective questionnaire scores (KSS) as in quality of life scored with a generic short-form health questionnaire (SF-12). At six months of follow-up, the MIS group scored a mean of 43.9 (standard deviation [SD] 10.5) in the physical subscale of the SF-12, whereas the traditional technique group scored a mean of 44.9 (SD 97.3), with no significant differences. The same happened with the mental subscales, i.e. 45.8 (SD 13.4) for the MIS group and 50.1 (SD 11.4) for the conventional technique group. KSS scores were 163.4 (SD 31.4) for the MIS group and 162.6 (SD 21.4) for the standard technique group without statistically significant differences. These results are concordant with other studies [5]. A recent systematic literature search of randomised controlled trials comparing minimally invasive and standard approaches in TKA [6] (meta-analysis of 13 trials published from 2007 to 2009) show that the mean KSS were better after MIS than after the standard procedure at six and 12 weeks postoperatively, but not after six months. Improvement in ROM occurred earlier in the MIS group six days after TKA, but later improvements are not clearly documented. These authors identified no differences between minimally invasive and standard approaches regarding the short-term overall complications and alignment of femoral and tibial components. However, wound healing problems and infections occurred more frequently in the MIS group. We believe that the presumed advantages of the MIS technique in knee arthroplasties disappear in medium-term. We have doubts about the usefulness of this technique in the clinical practice of an orthopaedic surgery unit, knowing the long learning curve that it requires [2]. This could be different in centres with special dedication to MIS surgery, such as that of the authors, where this technique may be a clinical alternative or a patient request.

Mini-Midvastus vs Standard Medial Parapatellar Approach: A Prospective, Randomized, Double-Blinded Study in Patients Undergoing Bilateral Total Knee Arthroplasty

The purpose of this study was to determine whether the mini-midvastus approach to total knee arthroplasty (TKA) results in differences in quadriceps muscle strength as well as previously cited advantages in a double blind prospective randomized trial. Twenty-seven patients (54 TKAs) scheduled for bilateral TKA were randomized to undergo mini-midvastus approach on one knee and standard approach on the other. Incision lengths were the same. Postoperative strength was determined by isokinetic and isometric peak torque testing. Range of motion, pain Visual analog scale, side-preference, and gait analysis were assessed preoperatively and postoperatively. The only significant difference in strength testing was increased isokinetic and isometric extension torque at 3 weeks postoperatively for the mini-midvastus approach. No differences between the mini-midvastus and standard approach were observed for stride length, stance time, pain Visual analog scale, or knee range of motion. The mini-midvastus approach has limited benefit compared to the standard approach for TKA.

Minimally Invasive Surgery Is Not a Risk Factor of Early Total Knee Arthroplasty Failure

Minimally invasive surgery (MIS) techniques have been developed with the goal of reducing recovery and improving outcomes. Critics argue that MIS reduces visualization and compromises technique, causing wound problems secondary to surgical trauma and increasing early failure. To determine whether MIS techniques lead to increased complications and early revisions, we reviewed our experience using a limited medial parapatellar approach in 3631 primary total knee arthroplasties (TKA) since 2003, in comparison with a historic control of 1291 primary TKA performed in 1994-1996 using a standard medial parapatellar approach. Fewer MIS than standard TKA required manipulation (5.4% vs 8.9%; P = 0.0001), had complications requiring reoperation (1.0% vs 2.1%; P = 0.0047), and required revision of one or more component parts for any reason (0.8% vs 4.4%; P = 0.0000). In our experience with more that 3600 primary MIS TKA with a rapid recovery protocol, excellent outcomes have been seen at up to 6 years follow-up, with a concomitant reduction compared with standard approach TKA in rates of manipulation and early complications requiring reoperation.

TKA using the subvastus approach and lateral retinacular release in patients with permanent post-traumatic patellar dislocation: a report of two cases

Permanent post-traumatic patellar dislocation is a rare condition, and total knee arthroplasty (TKA) can be performed for osteoarthritic knees with this condition. There have been only a few reports about using the standard medial parapatellar approach and extensive lateral release or extensor mechanism realignment for patients with permanent post-traumatic patellar dislocation. We performed two TKAs with using a subvastus approach and lateral release for osteoarthritic knees with permanent post-traumatic patellar dislocation. The patients were well satisfied with their results. The patellae tracked very well in the femoral trochlear groove throughout the full range of motion after the operations. Bone scans were done 1 year postoperatively on both patients, and the scans showed normal vascularity for the patella.

Konventionelle Navigation ohne Computer und der laterale minimal-invasive Zugang beim kontrakten Valgusknie

Valgus arthritic knees can basically be operated on by either a standard medial or a specific lateral approach. The classic lateral approach according to Keblish has some advantages, but also some disadvantages, relative to the standard medial parapatellar approach. A less invasive lateral approach means that osteotomy of tibia tubercle and eversion of the patella is no longer necessary. In view of our positive experiences with the minimally invasive surgical technique used for implantation of the lateral unicondylar prosthesis and for total knee arthroplasty in the case of varus knees, we have developed a minimally invasive lateral technique for use in valgus knees. The approach is a modification of the classic lateral approach used by Keblish. The procedure involves a lateral mini-arthrotomy with no need for osteotomy of the tubercle or eversion of the patella, and the surgery takes place step by step from a lateral approach. Modified cutting standard instruments are used. All operations have been carried out using "conventional navigation" without computers. This consists in preoperative planning based on radiographs of the whole leg, intraoperative controls before and after bone cuts, planning of the rotational positioning of the femur and tibia and postoperative checks of the alignment on standing radiographs of the whole leg. Preliminary results observed in the first 63 consecutive patients (average age 45-85 years) with contract valgus deformity [average 12 degrees valgus (6-19 degrees )] are very promising. Since 2004 we have used minimally invasive medial and lateral mini-midvastus approaches routinely for nearly all our primary total knee arthroplasties.

Minimally Invasive versus Standard Approach in Total Knee Arthroplasty

We compared a group of 20 patients who had 24 minimally invasive total knee arthroplasties with a similar group of 21 patients who had 25 standard medial parapatellar approach total knee arthroplasties. We wanted to clarify whether the minimally invasive group had an advantage over the standard group in muscle strength, pain level, postoperative recovery, and clinical results and whether the patients were prone to radiographically poor results, more operative time, and increased complications. The extensor and flexor torque, visual analog scale, pace of rehabilitation, Knee Society scores, radiographic findings, operative time, and complications of each group were examined. The minimally invasive group showed higher extensor torque values, higher ratios of postoperative to preoperative extensor torque, and lower average visual analog scale scores at 1 and 2 weeks. The patients in this group achieved straight leg raising, 90[degrees] knee flexion, and T-cane gait earlier. There was no component malalignment, but the tibial component shifted to a more medial position. The mean operative time was 56 minutes longer in the minimally invasive group. We encountered no major perioperative complications in either group. We believe the minimally invasive technique positively contributes to the early restoration of quadriceps strength and a speedy return to normal function.

Patellar blood flow during knee arthroplasty surgical exposure: Intraoperative monitoring by laser doppler flowmetry

Patellofemoral complications following knee arthroplasty are a well-known problem. Patellar ischemia has been suspected to be causative for fracture, anterior knee pain, and patella component failure. The purpose of this study was to assess the influence of knee arthroplasty surgical dissection on patellar blood flow. Patellar blood flow was measured by means of intraosseous laser Doppler flowmetry (LDF) in 10 patients undergoing total knee arthroplasty by a standard medial parapatellar approach. The initial blood flow was 121.6 +/- 114.7 AU. The signal significantly decreased by 71% (p = 0.0051) when the knee was flexed and lost the pulsatile signal pattern in 80%. After arthrotomy, the signal was 100.1 +/- 120.3 AU in extension. The lowest signal was found in flexion and eversion of the patella (mean, 18 +/- 10.7 AU) and all signals lost pulsatility. As compared to the initial values, completion of the soft tissue dissection did not lead to a significant change of the blood flow signal (121.3 +/- 104.8; p = 0.6835). Flexion of the knee joint markedly reduced patellar perfusion. Standard medial parapatellar approach did not significantly change patellar blood flow. This study does not support the theory of postoperative patellar ischemia as a cause of anterior knee pain or patellofemoral problems.

A Mini-Midvastus Capsular Approach With Patellar Displacement Decreases the Prevalence of Patella Baja

Our aim in this study was to evaluate the prevalence of patella baja after total knee arthroplasty (TKA) using 2 different surgical techniques. Postoperative changes in patella height were measured on serial radiographs of 74 TKAs implanted using a mini-midvastus capsular approach without patella eversion (group 1) and 57 TKAs implanted using a standard medial parapatellar capsular approach with patella eversion (group 2). Preoperative and postoperative Knee Society scores, operative data, and complications were compared. With a cutoff level of 5% shortening, the prevalence was 12% in group 1 and 37% in group 2 ( P = .001). The presence of patella baja was related to reduced flexion and increased pain as early as 1 year after TKA.

Sub-vastus approach versus the medial parapatellar approach in primary total knee: a randomised controlled trial [ISRCTN44544446

BackgroundThirty thousand knee replacements are performed annually in the UK. There is uncertainty as to the best surgical approach to the knee joint for knee arthroplasty. We planned a randomised controlled trial to compare a standard medial parapatellar arthrotomy with sub-vastus arthrotomy for patients undergoing primary total knee arthroplasty in terms of short and long term knee function.MethodsPatients undergoing primary total knee arthroplasty at the local NHS Trust are to be recruited into the study. Patients are to be randomised into either the subvastus or medial parapatellar approache to knee arthroplasty. The primary outcome measures will be the American Knee Society and WOMAC Scores. The secondary outcome measures will be patient based measures of EuroQol and SF-36. All outcomes will be measured pre-operatively, 1, 6, 12 and 52 weeks post-operatively. We will also review pain intensity using a pain and analgesia diary. Ease of surgical exposure and complications will also be analysed.DiscussionEvidence is lacking concerning the best surgical approach to the knee joint for patients undergoing primary total knee replacement. This pragmatic randomised trial tests the hypothesis that the sub-vastus approach is significantly superior to the standard medial parapatellar approach in terms of short and long term knee function.

Total knee arthroplasty: good agreement of clinical severity scores between patients and consultants

BackgroundNearly 20,000 patients per year in the UK receive total knee arthroplasty (TKA). One of the problems faced by the health services of many developed countries is the length of time patients spend waiting for elective treatment. We therefore report the results of a study in which the Salisbury Priority Scoring System (SPSS) was used by both the surgeon and their patients to ascertain whether there were differences between the surgeon generated and patient generated Salisbury Priority Scores.MethodsThe Salisbury Priority Scoring System (SPSS) was used to assign relative priority to patients with knee osteoarthritis as part of a randomised controlled trial comparing the standard medial parapatellar approach versus the sub-vastus approach in TKA. The operating surgeons and each patient completed the SPSS at the same pre-assessment clinic. The SPSS assesses four criteria, namely progression of disease, pain or distress, disability or dependence on others, and loss of usual occupation. Crosstabs and agreement measures (Cohen's kappa) were performed.ResultsOverall, the four SPSS criteria showed a kappa value of 0.526, 0.796, 0.813, and 0.820, respectively, showing moderate to very good agreement between the patient and the operating consultant. Male patients showed better agreement than female patients.ConclusionThe Salisbury Priority Scoring System is a good means of assessing patients' needs in relation to elective surgery, with high agreement between the patient and the operating surgeon.

Short-Term Results of Primary Total Knee Arthroplasties Performed with a Mini-Incision or a Standard Incision

A consecutive series of 144 patients who underwent 288 primary total knee arthroplasties (144 with use of a mini-incision [≤10 cm, quadriceps-sparing approach] and 144 with use of a standard incision [16-25 cm, standard medial parapatellar approach]) were studied. No significant differences were found between the groups with respect to the knee score, range of motion, hospital data, and radiographic parameters. An iatrogenic tear of quadriceps tendon occurred in 0% of the standard incision cases; however, it occurred in 100% of the mini-incision cases. Although there was no difference in all parameters in both groups, most patients favor a shorter scar. Therefore, we recommend a standard approach with as short an incision as possible, unless patients are markedly overweight, heavy-muscled, and large individuals.

Minimally Invasive Lateral Approach to Total Knee Arthroplasty

The minimally invasive lateral approach may have advantages over a standard total knee arthroplasty incision. The following pilot study compares this lateral approach to a standard medial parapatellar approach to total knee replacement. Twenty-six knees utilizing this minimally invasive lateral approach for total knee arthroplasty were followed. These were compared with 53 knees with a standard medial parapatellar approach. Subjective and objective Knee Society scores, quadriceps function, visual analog pain scores, and various quality of life measures (SF-12 and other questionnaires) were analyzed. Mean follow up was 2 years. Patients in the lateral approach group had minimal anterior knee pain and reduced analgesic use, although a higher incidence of complications was encountered. A radiographic evaluation showed no difference in various radiographic indices between both groups. The preliminary results of this study are encouraging and warrant further investigation into techniques that would make the lateral approach safer for total knee replacement.

Comparison of Midvastus and Medial Parapatellar Approach for Total Knee Arthroplasty

Purpose: To compare the results associated with the standard medial parapatellar approach and the midvastus approach in primary total knee arthroplasty. Materials and Methods: A total of 70 cases who underwent total knee arthroplasty were evaluated. All patients have varus deformity in standing AP view, but subluxation of the patella on the Merchant view was excluded. Medial parapatellar approach (35 cases) and midvastus approach (35 cases) were used. The operation time, blood loss, incidence of lateral release, time to perform straight leg raising, time to get flexion, range of motion, VAS, Knee Society Knee Scores, tibio-femoral angle and patella tilt were compared. The results were analyzed using the student's t-test. Results: No significant difference was noted between medial parapatellar and midvastus approach regarding to the operation time, blood loss, range of motion, VAS and Knee Society Knee Scores (p>0.05). However, midvastus approach provide two significant advantages of the incidence of lateral release (40% vs 6%) and the time to perform straight leg raising (4.5 days vs 1.9 days) (p

Minimally Invasive Total Knee Replacement through a Mini-midvastus Incision

Total knee replacement traditionally has been done through an anterior incision approximately 18 cm long, using a capsular incision that separates the interval between the rectus femoris and vastus medialis musculature. Although giving excellent exposure, this incision also disrupts the suprapatellar pouch and may lead to adhesions and difficulty with rapidly regaining flexion. It is hypothesized that, by using a more minimally invasive incision, there will be a more rapid return of flexion and the patient will require fewer narcotic medications postoperatively. This retrospective review compared 32 total knee replacements done through a minimally invasive mini-midvastus approach with 26 total knee replacements done through the standard medial parapatellar approach. Preoperative Knee Society scores and postoperative functional outcomes were compared. Postoperative flexion was measured daily during hospitalization and at a 6-week and 3-month followup. Pain was assessed by a visual analog scale and the amount of pain medication used during hospitalization. Implant position was measured. The MIS group had an average skin incision length of 12.8 cm. Passive flexion on a daily basis was significantly higher in the MIS group compared with the standard group. At 6 weeks postoperatively, the change in Knee Score was statistically higher in the MIS group and the average visual analog pain score and the total amount of pain medication was lower. The radiographic alignment and position of all the components was normal in all patients in both groups. The limited disruption of the extensor mechanism results in more rapid restoration of the quadriceps muscle control.