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

Compare the Quadriceps Activity between Mini-Midvastus and Mini-Medial Parapatellar Approach in Total Knee Arthroplasty with Electromyography

Background: The comparison between the mini-midvastus (mini-MV) and mini-parapatellar (mini-MPP) approach in total knee arthroplasty (TKA) remains a subject of debate. The present study compared quadriceps activation, pain levels, and clinical outcomes between the two approaches; quadricep activation was assessed using surface electromyography (sEMG). Methods: This retrospective cross-sectional study comprised a total of 78 patients aged between 50 and 85 years with primary osteoarthritis. Patients were divided into a mini-MV (n = 38) group and a mini-MPP (n = 40) group according to the surgical approach. Results: The two groups exhibited no significant differences in sEMG for the vastus medialis (VM) or rectus femoris (RF) at the follow-up time points, with the exception that the mini-MV group exhibited superior strength of RF during extensions at the 2-week follow-up. However, the mini-MPP group had superior Western Ontario and McMaster Universities Index (WOMAC) total and function scores at the 2- and 6-week follow-ups. The mini-MPP group also had superior WOMAC stiffness scores at the 2-week follow-up. The two groups did not differ significantly in terms of pain levels or morphine consumption. Conclusions: The sEMG data of quadriceps muscle would not differ significantly between the mini-MV and mini-MPP approaches for TKA. Moreover, the mini-MPP approach may yield superior WOMAC scores when compared with the mini-MV approach.

Clinical and Radiological Outcomes of Total Knee Arthroplasty Performed with Midvastus and Medial Parapatellar Approaches in Obese Patients

Background

The use of total knee arthroplasty (TKA) for primary osteoarthritis of the knee has remarkably increased recently. We aimed to compare the clinical and radiological outcomes of TKA in obese patients (>30 kg/m²) operated with midvastus (MV) or medial parapatellar (MPP) approaches.

Methods

This retrospective study was performed using data derived from 80 patients (70 women; 10 men) with an average age of 66.17 ± 5.42 (range: 54 to 77). Patients were allocated into 2 groups as for the type of approach conducted during TKA: group I (n = 41) underwent TKA by MV approach, while the MMP technique was used in group II (n = 39).

Results

Demographic, clinical, and radiological parameters included age, side of involvement, sex, BMI, diameters of thigh and calf, length of incision, duration of operation, amount of bleeding and transfusion, duration of hospitalization and follow-up, complications, and range of motion, as well as Knee Society Score (KSS) and Knee Society Function Score (KSFS). Patients with a higher BMI (≥35 kg/m²) experienced more profound bleeding and needed more transfusion of erythrocyte suspension. The range of motion was more favorable in groups with BMI <35 kg/m². The functional outcomes as reflected in KSS and KSFS were much better in patients with BMI <35 kg/m².

Conclusions

Our data indicated that obesity can adversely influence the clinical and radiological outcomes after TKA performed by both MV and MPP approaches. A careful analysis of patient characteristics and selection of appropriate operative procedures is critical. Further randomized, controlled trials on larger series must be designed to elucidate the relationship between obesity and therapeutic outcomes after TKA with different approaches.

Which is the better choice? A clinical cohort study protocol evaluating the differences between standard medial parapatellar and minimally invasive approaches in total knee replacement

BACKGROUND

There is still a lack of consensus on the best approach for total knee replacement (TKR). We carried out this present retrospective cohort study to assess the overall safety and effectiveness of a minimally invasive approach without the use of computer navigation in comparison with conventional TKR.

METHODS

A retrospective review of patients who receiving the primary TKR in the same institution from 2014 to 2016 was conducted. The inclusion criteria for the study indicated that the patient required a unilateral or bilateral TKR was between 18 and 80 years' old, provided informed consent, was followed up for at least 2 years, and was in stable health. There was no treatment for any condition or condition that might pose a risk of excessive surgery. The same TKR standard rehabilitation program was provided to all patients. Data were collected on patient demographics, anesthesia style, American Society of Anesthesiology scores, tourniquet duration, and surgical drainage loss. Our primary outcome measure was discharge time. Secondary outcomes included duration of surgery, incidence of postoperative complications, imaging location 6 weeks after surgery, Oxford Knee Score, Western Ontario and McMaster Universities Arthritis Index, and knee ROM. Complications were recorded and classified as surgical site, thromboembolic, systemic, or requiring reoperation.

RESULTS

It was assumed that there is a remarkable difference in postoperative outcomes between the 2 groups.

CONCLUSION

The limitations of our present research include the inherent limitations in any retrospective cohort research, including the observation bias and possibility of selection.

TRIAL REGISTRATION

This study protocol was registered in Research Registry (researchregistry6349).

Better outcomes after minimally invasive surgeries compared to the standard invasive medial parapatellar approach for total knee arthroplasty: a meta-analysis

PURPOSE

Minimally invasive surgery (MIS) for total knee arthroplasty (TKA) is often marketed as being able to speed up healing times over standard invasive surgery (SIS) through the medial parapatellar approach. The advantages of these minimally invasive approaches, however, are not yet definitively established. A meta-analysis of studies comparing peri-operative and post-operative differences and long-term complications of MIS versus SIS for TKA was conducted.

METHODS

This meta-analysis was conducted following the PRISMA guidelines. The Pubmed, Google Scholar, Scopus, and Embase databases were accessed in September 2020. All clinical trials comparing minimally-invasive versus standard approaches for TKA were considered. Only studies reporting quantitative data under the outcomes of interest were included. Methodological quality assessment was performed using the PEDro appraisal score.

RESULTS

This meta-analysis covers a total of 38 studies (3296 procedures), with a mean 21.3 ± 24.3 months of follow-up. The MIS group had shorter hospitalization times, lower values of total estimated blood loss, quicker times of straight-leg raise, greater values for range of motion, higher scores on the Knee Society Clinical Rating System (KSS) and its related Function Subscale (KSFS). Pain scores, anterior knee pain and revision rate were similar between MIS and SIS. SIS allowed a quicker surgical duration.

CONCLUSION

The present meta-analysis encourages the use of minimally invasive techniques for total knee arthroplasty. However, MIS TKA is technically demanding and requires a long learning curve.

LEVEL OF EVIDENCE

III, meta-analysis of clinical trials.

Patient-specific instrumentation improves functional kinematics of minimally-invasive total knee replacements as revealed by computerized 3D fluoroscopy

BACKGROUND AND OBJECTIVES

Minimally-invasive total knee arthroplasty (MIS-TKA) has demonstrated very good short-term success, but its mid- to long-term results remain inconclusive. The success may be related to the tradeoff between a small incision and accurate positioning of the implant components. Patient-specific instrumentation (PSI) aims to improve the accuracy in restoring the knee axis and the clinical outcomes for MIS-TKA, but the results are yet to be confirmed by accurate assessment during functional activities. The purpose of the current study was to measure and compare the in vivo three-dimensional (3D) rigid-body and surface kinematics of MIS-TKA implanted with and without PSI during isolated knee active flexion/extension and sit-to-stand using state-of-the-art 3D model-based fluoroscopy technology.

METHODS

Ten patients treated for advanced medial knee osteoarthritis by MIS-TKA without PSI (non-PSI group) and nine with PSI (PSI group) participated in the current study. Each subject performed non-weight-bearing knee flexion/extension and sit-to-stand tasks while the motion of the prosthetic knee was under bi-plane fluoroscopy surveillance. The computer models of each of the knee prosthesis components were registered to the measured fluoroscopy images for each time frame via a novel validated 3D fluoroscopy method. Non-parametric 1-tailed Mann-Whitney tests were performed to detect the differences in the joint and surface kinematic variables every 10° of knee flexion between the non-PSI and PSI groups. The 1-tailed significance level was at α = 0.05.

RESULTS

The PSI group showed clear, coupled flexion/internal rotation during activities, while the non-PSI group remained roughly at an externally rotated position with slight internal rotations. The coupled rotation in the PSI group was accompanied by an anterior displacement of the medial contact and a posterior displacement of the lateral contact, which was different from the screw-home mechanism. Neither of the two groups showed the normal roll-back phenomenon, i.e., posterior translation of the femur relative to the tibia during knee flexion.

CONCLUSIONS

With the state-of-the-art 3D fluoroscopy method, differences in both the rigid-body and surface kinematics of the prosthetic knees between MIS-TKA with and without PSI were identified. Patients with PSI demonstrated significant positive effects on the reconstructed rigid-body kinematics of the knee, showing clearer coupled flexion/internal rotations - an important kinematic characteristic in healthy knees - than those without PSI during activities with or without weight-bearing. However, none of them showed normal contact patterns. The current findings will be helpful for surgical instrument design, as well as for surgical decision-making in MIS total knee arthroplasty.

Better outcomes after mini-subvastus approach for primary total knee arthroplasty: a Bayesian network meta-analysis

Introduction

Alternatives to the classical medial parapatellar (MPP) approach for total knee arthroplasty (TKA) include the mini-medial parapatellar (MMPP), mini-subvastus (MSV), mini-midvastus (MMV) and quadriceps-sparing (QS) approaches. The best approach has been not fully clarified. The purpose of the present study was to conduct a Bayesian network meta-analysis comparing these approaches.

Materials and methods

The present analysis was carried out according to the PRISMA extension statement for reporting systematic reviews incorporating network meta-analyses of healthcare interventions. The databases search was performed in October 2019. All clinical trials comparing two or more approaches for primary TKA were considered for inclusion. The baseline comparability was evaluated through the analysis of variance (ANOVA) test. The statistical analysis was performed through the STATA software/MP. A Bayesian hierarchical random-effects model analysis was adopted in all the comparisons.

Results

Data from 52 articles (4533 patients) were collected. The mean follow-up was 20.38 months. With regard to diagnosis, gender, age and BMI, adequate baseline comparability was detected. The MSV approach ranked better concerning clinical scores (the lowest visual analogic scale, the higher KSS and KSFS) and functional outcomes (the shortest straight leg raise, the greatest degree of flexion and range of motion). Concerning perioperative data, the MSV evidenced the shortest hospital stay, while the MPP the shortest surgical duration and lowest estimated blood loss.

Conclusion

According to the main findings of the present study, the mini-subvastus approach for total knee arthroplasty demonstrated superior overall compared to the other approaches. Orthopaedic surgeons should consider this approach in the light of the evidence and limitations of this Bayesian network meta-analysis.

Characteristics of young and lower functioning patients following total knee arthroplasty: a retrospective study

BACKGROUND

Rates of total knee arthroplasty (TKA) procedures in younger, more medically complex patients have dramatically increased over the last several decades. No study has examined categorization of lower and higher functioning subgroups within the TKA patient population. Our study aimed to determine preoperative characteristics of younger patients who are lower functioning following TKA.

METHODS

Patients were categorized into higher and lower functioning subgroups defined using a median split of 1) postoperative Timed Up and Go (TUG) test times and 2) Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) physical function subscale scores. A split in age (65 years) was used to further classify patients into four categories: younger lower functioning, younger higher functioning, older lower functioning and older higher functioning. Measures from preoperative domains of health, psychological, physical performance and pain severity were examined for between-group differences.

RESULTS

Comparing mean values, the younger lower functioning subgroup using the TUG had significantly weaker knee extensor, slower gait speed, higher body mass index and greater pain compared to other subgroups. The younger lower functioning subgroup using the WOMAC physical function subscale demonstrated higher pain levels and Coping Strategies Questionnaire-Catastrophizing Subscale scores compared to the older lower functioning subgroup.

CONCLUSIONS

Poorer preoperative physical performance and pain severity appear to have the largest influence on early postoperative TKA recovery in younger lower functioning patients relative to both younger and older higher functioning patients.

Minimally invasive total knee replacement: techniques and results

In this review, we outlined the definition of minimally invasive surgery (MIS) in total knee replacement (TKR) and described the different surgical approaches reported in the literature. Afterwards, we went through the most recent studies assessing MIS TKR. Next, we searched for potential limitations of MIS knee replacement and tried to answer the following questions: Are there selective criteria and specific patient selection for MIS knee surgery? If there are, then what are they? After all, a discussion and conclusion completed this article. There is certainly room for MIS or at least less invasive surgery for appropriate selected patients. Nonetheless, there are differences between approaches. Mini-medial parapatellar is easy to master, quick to perform and potentially extendable, whereas mini-subvastus and mini-midvastus are trickier and require more caution related to risk of haematoma and vastus medialis oblique (VMO) nerve damage. Current evidence on the safety and efficacy of mini-incision surgery for TKR does not appear fully adequate for the procedure to be used without special arrangements for consent and for audit or continuing research. There is an argument that a sudden jump from standard TKR to MIS TKR, especially without computer assistance such as navigation, patient-specific instrumentation or robotic, may breach a surgeon's duty of care towards patients because it exposes patients to unnecessary risks. As a final point, more evidence is required on the long-term safety and efficacy of this procedure which will give objective shed light on real benefits of MIS TKR.

Minimally invasive versus conventional approaches in total knee replacement/arthroplasty: A review of the literature

Background

Life expectancy lengthening and aging of population resulted in dramatically increase of patients with osteoarthritis. Total knee arthroplasty is widely used as the gold standard in order to relieve pain, correct deformity and restore function. A contemporary and controversial topic, is that of minimally invasive surgery for TKA. The minimally invasive approaches are based on the concept that they don't violate the extensor mechanism, resulting in earlier functional recovery, shorter hospital stay and enhanced patients' overall satisfaction. The most commonly used MIS approaches in TKA are the subvastus, midvastus and the quadriceps sparing. There is a debate regarding the efficacy and safety of these methods.

Objective

In this article we will review the current literature (randomized controlled trials and systematic reviews/meta-analyses) on MIS compared to traditional approach and analyse their clinical safety, efficacy and long-term results.

Design

Comparison of well-designed studies have tried to demonstrate the advantages/disadvantages, the clinical results and the complications of the MIS approaches compared to the MPP approach.

Results

MIS approaches seem to provide advantages in the immediate post-operative period accompanied by increased reports of complications. Consequently, further investigation based on large well-designed studies with long-term results are warranted to further clarify MIS effectiveness/safety.

Medial subvastus versus the medial parapatellar approach for total knee replacement: A systematic review and meta-analysis of randomized controlled trials

Twenty randomized controlled trials comprising 1893 primary total knee replacements were included in this review.

The subvastus approach conferred superior results for mean difference (MD) in time to regain an active straight leg raise (1.7 days, 95% confidence interval [CI] 1.0 to 2.3), visual analogue score for pain on day one (0.8 points on a scale out of 10, 95% CI 0.2 to 1.4) and total range of knee movement at one week (7°, 95% CI 3.2 to 10.7). The subvastus approach also resulted in fewer lateral releases (odds ratio 0.4, 95% CI 0.2 to 0.7) and less peri-operative blood loss (MD 57 mL, 95% CI 10.5 to 106.4) but prolonged surgical times (MD 9.7 min, 95% CI 3.9 to 15.6).

There was no difference in Knee Society Score at six weeks or one year, or the rate of adverse events including superficial or deep infection, deep vein thrombosis or knee stiffness requiring manipulation under anaesthesia.

This review demonstrates evidence of early post-operative benefits following the subvastus approach with equivalence between approaches thereafter.

Cite this article: EFORT Open Rev 2018;3:78-84. DOI: 10.1302/2058-5241.3.170030.

Biochemical stress evaluation after medial parapatellar and subvastus approach in total knee replacement

INTRODUCTION

Even if different surgical approaches for total knee arthroplasty are well known since decades, the standard medial parapatellar incision remains the most common one; general agreement about significant advantages with minimally invasive techniques is lacking. Furthermore, the surgical stress effect on the organism has always been analyzed through blood inflammatory parameters. This study aim was to compare the standard and subvastus approaches, using the salivary cortisol in particular as measure for systemic surgery-related stress.

METHODS

Fifteen operations were performed in a consecutive series; clinical (Knee Society Knee Scoring System., a questionnaire score, range of motion, tourniquet time, intra-operative bleeding) and biochemical factors (salivary and hematic cortisol, C-reactive protein, muscular creatine phosphokinase levels) were evaluated. The final follow-up was at two months after the operation.

RESULTS

No significant differences were observed in most of the parameters; however, the subvastus group had a sharper and earlier functional improvement trend than the standard one. On the other side, it increased the CPK levels significantly.

CONCLUSIONS

In our experience, the medial subvastus approach, firstly associated with greater surgical stress, has then been characterized by a more favorable functional improvement trend. Moreover, the salivary cortisol measurement has proved to be a non-invasive and reliable method to evaluate the systemic surgery-related stress.

Quality of cementation in conventional versus minimally invasive total knee arthroplasty

PURPOSE

To review the immediate postoperative radiographs of 108 patients following conventional or minimally invasive total knee arthroplasty (TKA) to assess the quality of cementation in terms of cement voids and retained cement.

METHODS

Records of 20 male and 88 female consecutive patients aged 50 to 83 (mean, 67.5) years who underwent conventional TKA (n=56) or computer-assisted minimally invasive TKA (n=52) for osteoarthritis by a single senior surgeon were reviewed. Immediate postoperative radiographs were assessed by a single blinded assessor for the quality of cementation in terms of cement void and retained cement in different zones of the femoral, tibial, and patellar components along the prosthesis-bone interface using the Knee Society total knee arthroplasty roentgenographic evaluation and scoring system.

RESULTS

The 2 groups were comparable in terms of baseline demographics as well as cement void and retained cement on the femoral, tibial, and patellar components, except that in the minimally invasive group, cement void beneath the anterior flange of the femoral component was wider (0.32 vs. 0 mm, p=0.001), and retained cement in the posterior or lateral aspects of the tibial component was more common (50.0% vs. 28.6%, p=0.018).

CONCLUSION

Minimally invasive TKA resulted in a wider cement void beneath the anterior flange of the femoral component and a higher rate of retained cement around the tibial component.

Patellar non-eversion in primary TKA reduces the complication rate

PURPOSE

This study was designed to evaluate the isolated benefits of patellar non-eversion in total knee arthroplasty (TKA).

METHODS

This systematic review and meta-analysis was conducted following the PRISMA statement. A comprehensive search of the MEDLINE/PubMed, Cochrane Library, and Embase databases was performed in August 2014. Randomized controlled trials (RCTs) that considered the handling of the patella as the only variable were included in our review. Quality assessment of RCTs was performed according to the CONSORT statement. The meta-analysis was performed to pool the available data for some parameters.

RESULTS

The searches of the MEDLINE/PubMed, Cochrane Library, and Embase databases yielded 10 RCTs, and five RCTs were selected for inclusion in the review. This results suggested that tourniquet time [mean difference (MD) = -5.69; 95% confidence interval (CI) -9.77 to -1.60], length of hospitalization (MD = 1.24; 95% CI 0.54-1.94) and the incidence of complications [odds ratio (OR) = 2.23; 95% CI 1.12-4.44] differed significantly between the eversion group and non-eversion group. No differences in postoperative pain, alignment, and the Insall-Salvati ratio were observed between the groups.

CONCLUSION

The patellar non-eversion approach offers a shorter length of hospitalization and lower incidence of postoperative complications, but requires more operative time. The merits of patellar non-eversion for recovery of knee function remain controversial, and more high-quality RCTs are needed to draw clear conclusions. In general, avoidance of patellar eversion is recommended when exposing the knee joint for TKA.

Computer-assisted total knee arthroplasty using mini midvastus or medial parapatellar approach technique: A prospective, randomized, international multicentre trial

Background

Despite the growing evidence in the literature there is still a lack of consensus regarding the use of minimally invasive surgical technique (MIS) in total knee arthroplasty (TKA).

Methods

A prospective, randomized, international multicentre trial including 69 patients was performed to compare computer-assisted TKA (CAS-TKA) using either mini-midvastus (MIS group) or standard medial parapatellar approach (conventional group).

Patients from 3 centers (Maastricht, Zwickau, Adelaide) with end-stage osteoarthritis of the knee were randomized to either an MIS group with dedicated instrumentation or a conventional group to receive cruciate retaining CAS-TKA without patella resurfacing. The primary outcome was to compare post operative pain and range of motion (ROM). The secondary outcome was to measure the duration of surgery, blood loss, chair rise test, quadriceps strength, anterior knee pain, Knee Society Score (KSS),WOMAC scores, mechanical leg axis and component alignment.

Results

Patients in the MIS group (3.97 ± 2.16) had significant more pain at 2 weeks than patients in the conventional group (2.77 ± 1.43) p = 0.003. There was no significant difference in any of the other primary outcome parameters. Surgery time was significantly longer (p < 0.001) and there were significantly higher blood loss (p = 0.002) in the MIS group as compared to the conventional group. The difference of the mean mechanical leg alignment between the groups was not statistically significant (–0.43° (95 % CI –1.50 – 0.64); p = 0.43).

There was no significant difference of component alignment between the two surgical groups with respect to flexion/extension (p = 0.269), varus/valgus (p = 0.653) or rotational alignment (p = 0.485) of the femur component and varus valgus alignment (p = 0.778) or posterior slope (p = 0.164) of the tibial component.

Conclusion

There was no advantage of the MIS approach compared to a conventional approach CAS-TKA in any of the primary outcome measurements assessed, however the MIS approach was associated with longer surgical time and greater blood loss. MIS-TKA in combination with computer navigation is safe in terms of implant positioning.

Trial registration number

ClinicalTrials.gov NCT02625311 8 December 2015

Chronic Non-Orthopedic Conditions More Common in Patients with Less Severe Degenerative Changes That Have Elected to Undergo Total Knee Arthroplasty

The purpose of this study was to determine whether the prevalence of chronic non-orthopedic conditions that may play a role in an abnormal pain response differs between patients based on the severity of degenerative changes at the time of surgery. Of 1020 OA knees that had undergone primary TKA with a minimum 2year follow-up, we identified 117 (11.5%) that had less severe degenerative changes. The prevalence of dissatisfaction was significantly greater in less severe group compared to those with moderate or severe changes (18.8% vs. 9.3%, P=.003). Chronic non-orthopedic conditions were significantly more prevalent in the less severe group with 41.9% reporting depression/anxiety, 30.8% with fibromyalgia or low back pathology, and 12.8% with a prior traumatic brain injury or stroke.

A meta-analysis of minimally invasive and conventional medial parapatella approaches for primary total knee arthroplasty

PURPOSE

Minimally invasive surgical (MIS) approaches for total knee arthroplasty (TKA) have become increasingly popular for doctors and patients. They have argued that it decreases post-operative pain, accelerates functional recovery and increases patient satisfaction due to less injury. However, critics are concerned about TKA's possible effects on component position and with complications, considering the procedure's limited exposure. The purpose of this study was to summarise the best evidence in comparing the clinical and radiological outcomes between MIS and a conventional approach in TKA.

METHODS

Electronic databases were systematically searched to identify relevant randomised controlled trials (RCTs). Our search strategy followed the requirements of the Cochrane Library Handbook. Methodological quality was assessed, and data were extracted independently by two authors.

RESULTS

Thirty studies, including 2,536 TKAs, were reviewed: 1,259 minimally invasive and 1,277 conventional exposure TKAs. The results showed that while the MIS group had longer operation times and tourniquet times, it had superior outcomes in KSS (objective and total), range of motion, flexion range of motion, flexion 90° day, straight leg-raising day, total blood loss and decrease in haemoglobin. However, wound-healing problems occurred more frequently in the MIS group. There were no statistically significant differences in other clinical or radiological outcomes between the MIS and conventional groups in TKA.

CONCLUSION

The preliminary results indicate that the MIS approach provides an alternative to the conventional approach, with earlier rehabilitation but no malpositioning or severe complications. Wound-healing problems can be treated easily and effectively, and the risk also decreases as surgeons become more experienced, and more user-friendly instruments are invented. Potential benefits in medium- and long-term outcomes require larger, multicentre and well-conducted RCTs to confirm.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

Teaching surgical exposures to undergraduate medical students: an integration concept for anatomical and surgical education

BACKGROUND

Decreasing numbers of students are interested in starting a surgical career, posing substantial challenges to patient care in the next years. The anatomy course is one of the key subjects in medical training, especially in surgical disciplines. Innovative teaching concepts that integrate surgically relevant anatomy and manual dexterity might help boost student interest in surgery.

METHODS

A preclinical workshop entitled "Surgical exposures" was developed. A team of anatomists and surgeons introduced the surgical exposures, demonstrating the procedures on Thiel-fixed body donors. Following this introduction, students practiced the exposures in an operating room-like manner. A six-point Likert scale was used to evaluate the workshop and to compare it to the first-year dissection course.

RESULTS

The overall evaluation result for the surgical exposures was excellent, proving to be a significantly better result when compared to the first-year dissection course. The students were more satisfied with the teaching time invested by the peers and regarded the workshop as clinically highly relevant. Furthermore, they felt that questions were addressed better and that the overall atmosphere was better than in the gross anatomy course. Subject to criticism was the course size and practicing time in both cases.

DISCUSSION

The surgical exposures workshop provides preclinical students with clinically relevant anatomy and manual dexterity. It may positively influence the decision to follow a surgical career. This course, however, requires extensive teaching resources. The given concept may help implement practical medical skills in the preclinical curriculum, strengthening the professional identity of surgeons and anatomists.

Short Term Recovery of Function following Total Knee Arthroplasty: A Randomised Study of the Medial Parapatellar and Midvastus Approaches

This pilot double blind randomised controlled study aimed to investigate whether the midvastus (MV) approach without patellar eversion in total knee arthroplasty (TKA) resulted in improved recovery of function compared to the medial parapatellar (MP) approach. Patients were randomly allocated to either the MV approach or the MP approach. Achievements of inpatient mobility milestones were recorded. Knee kinematics, muscle strength, Timed Up and Go, WOMAC, and daily step count were assessed before and up to six months after surgery. Cohen's effect size d was calculated to inform the sample size in future trials. Twenty-eight participants (16 males, 12 females) participated. Patient mobility milestones such as straight leg raise were achieved on average 1.3 days (95% CI −3.4 to 0.7, d = 0.63) earlier in the MV group. Knee extensor strength at 6 weeks after surgery was higher (95% CI −0.38 to 0.61, d = 0.73) in the MV group. No trends for differences between the groups were observed in knee kinematics, TUG, WOMAC, or step count. Our results suggest a short term advantage in the first 6 weeks after surgery of the MV approach over the MP approach, but a larger study is required to confirm these findings. This trial is registered with NCT056445.

Does the length of incision in the quadriceps affect the recovery of strength after total knee replacement?

We have compared the time to recovery of isokinetic quadriceps strength after total knee replacement (TKR) using three different lengths of incision in the quadriceps. We prospectively randomised 60 patients into one of the three groups according to the length of incision in the quadriceps above the upper border of the patella (2 cm, 4 cm or 6 cm). The strength of the knees was measured pre-operatively and every month post-operatively until the peak quadriceps torque returned to its pre-operative level.

There was no significant difference in the mean operating time, blood loss, hospital stay, alignment or pre-operative isokinetic quadriceps strength between the three groups. Using the Kaplan–Meier method, group A had a similar mean recovery time to group B (2.0 ± 0.2 vs 2.5 ± 0.2 months, p = 0.176). Group C required a significantly longer recovery time (3.4 ± 0.3 months) than the other groups (p < 0.03). However, there were no significant differences in the mean Oxford knee scores one year post-operatively between the groups.

We conclude that an incision of up to 4 cm in the quadriceps does not delay the recovery of its isokinetic strength after TKR.

Cite this article: Bone Joint J 2014;96-B:902–6.

Mini-midvastus versus mini-medial parapatellar approach for minimally invasive total knee arthroplasty: outcomes pendulum is at equilibrium

Comparisons between mini-midvastus (mMV) and mini-medial parapatellar approach (mMPP) for total knee arthroplasty (TKA) have reported variable results. We compared two approaches with minimum two year follow up. Forty consecutive patients who underwent staged bilateral TKA were prospectively randomized for mMPP approach in one knee and mMV approach in the other. Clinical parameters (muscle strength, pain, ROM, Knee Society Score) and surgic.l parameters (duration of surgery, blood loss, lateral releases) were assessed at 2, 6, 12 weeks and 6, 12, 24 months postoperatively. Clinical outcomes revealed inconsistent pattern of differences at various intervals. Surgical outcomes were not different. There were no major differences in outcomes between the two approaches. We recommend someone use surgical approach with which they are most familiar.

Postoperative pain and contracture following total knee arthroplasty comparing parapatellar and subvastus approaches

The purpose of this study was to see if subvastus approach would decrease incidence of postoperative contracture and pain following TKA compared to standard parapatellar approach. Retrospective review of 546 patients in Group A undergoing TKA using parapatellar approach were compared to 255 patients in Group B undergoing subvastus approach. No statistically significant differences regarding OR time, blood loss, BMI, or LOS. Total of 23 (4%) manipulations under anesthesia for contracture in Group A compared to 6 (2%) in Group B (p>0.05). Postoperative pain scores at 6 weeks was greater in Group A, p<0.05. We feel that a subvastus approach minimizes trauma to the extensor mechanism, and therefore decreases the incidence of postoperative pain following TKA.

Faster quadriceps recovery with the far medial subvastus approach in minimally invasive total knee arthroplasty

PURPOSE

To identify whether less proximal muscle damage during minimally invasive surgery will allow faster recovery after total knee arthroplasty in comparison with a quadriceps incision approach. A limited medial parapatellar approach without tibial medial collateral ligament (MCL) release was compared to a subvastus approach without tibial medial collateral ligament release (far medial subvastus).

METHODS

One hundred and eighty patients were studied. In the mini-parapatellar group, ninety patients and in the far medial subvastus group, the remaining ninety patients were included. The evaluation was based on the Knee Society Score, VAS, morphine consumption, range of motion, time to straight leg raising, walking without aid, stairs and period of hospitalization. Alignment on full leg radiographs and component position on plain films were measured.

RESULTS

The far medial subvastus group showed faster recovery with earlier straight leg raising (1.7 ± 0.5 vs. 2.7 ± 0.4 days), postoperative weight bearing without aid (1.7 ± 0.6 vs. 2 ± 0.8 days) and stair negotiation (3 ± 0.4 vs. 4 ± 0.3 days) resulting in shorter length of stay (4 ± 0.5 vs. 5 ± 1.2 days). Comparable Knee Society Scores (88.5 ± 6.8 vs. 90 ± 10), Function Scores (90 ± 10) and alignment (5.4° ± 2.1° vs. 5.0° ± 2.4°) between the medial parapatellar and far medial subvastus group were observed at a follow-up of 24 months. An increase in operative time for the far medial subvastus was observed (55 ± 10.6 min vs. 67 ± 12 min tourniquet time) but without complications.

CONCLUSION

The MCL sparing far medial subvastus approach allows good surgical exposure, faster straight leg raising, full weight bearing without aid and shorter length of stay with most importantly no radiological malalignment.

LEVEL OF EVIDENCE

Therapeutic study, Level II.

[Minimally invasive surgery versus conventional surgery. A review of the scientific evidence]

The concept that small incisions lead to a better outcome in many procedures has extended into most surgical areas, orthopaedic surgery among them. However, in some cases there is not enough scientific evidence to recommend these procedures. This article attempts to provide an updated review of the works published with sufficient scientific evidence on the advantages of minimally invasive surgery (MIS) compared to conventional access approaches. The published articles, meta-analyses and systematic literature reviews with level I or II evidence are reviewed in topographic order. Wherever possible, the information available on the costs-benefits of this type of surgery is also reviewed.

Mini-midvastus versus medial parapatellar approach in TKA: muscle damage and inflammation markers

The purpose of this prospective study was to analyze the biochemical markers of muscle damage and inflammation in patients treated with the mini-midvastus approach or the medial parapatellar approach for total knee arthroplasty. Of 60 patients who underwent unilateral total knee arthroplasty, 30 were treated with the mini-midvastus approach (MMV group) and 30 were treated with the medial parapatellar approach (MPP group). Serum creatine kinase, myoglobin, lactate dehydrogenase, glutamic oxaloacetic transaminase, C-reactive protein, interleukin-6, and interleukin-1β levels were measured preoperatively, immediately postoperatively (except for C-reactive protein level), and on postoperative days 1, 2, and 3. Student's t test, Pearson's chi-square test, and Fisher's exact test were used to compare the outcomes between the 2 groups. Compared with the MPP group, a significant increase in serum creatine kinase level existed in the MMV group on postoperative days 2 (P=.08) and 3 (P=.09) and cumulatively (P=.02). However, significantly elevated C-reactive protein and interleukin-6 levels existed in the MPP group.According to the serum creatine kinase levels, the mini-midvastus approach has no superiority over the medial parapatellar approach in terms of sparing muscle and may cause more muscle damage. Further study is warranted to determine the correlation between biochemical markers and functional deficits.