Modified Bösch Osteotomy Combined With a Percutaneous Adductor Tendon Release for the Treatment of Hallux Valgus Deformity: Learning Curve

PURPOSE

The expression "learning curve" indicates the relation between the time needed to learn a new technique and the technique-related outcome. Percutaneous surgery (also called "minimally invasive surgery") has experienced sustained and respectable growth, especially in forefoot deformities. The main purpose was to assess the number of feet necessary to become skilled in a specific minimally invasive surgery (MIS) procedure.

METHODS

From January 2015 to June 2018, 46 consecutive patients were evaluated and included in the study. Patients were divided into 2 groups according to the surgery period: first 30 feet (Group 1), and subsequent 30 feet (Group 2) from the whole population evaluated. Age, body mass index, and operative time were evaluated. Hallux valgus angle and the 1 to 2 intermetatarsal angle were also measured. Patients were assessed according to the American Orthopedic Foot and Ankle Society (AOFAS) forefoot scale, the Foot and Ankle Ability Measure activities of daily living (FAAM ADL) subscale and the visual analog scale (VAS).

RESULTS

The comparison of the 2 groups showed statistically significant differences in hallux valgus angle (HVA) but not in intermetatarsal angle (IMA). The mean improvement between pre- and postoperative FAAM ADL, VAS, and AOFAS score in Group 1 were 12.83, 3.93, and 24.77 points, respectively. In Group 2, the mean improvement between pre- and postoperative FAAM ADL, VAS, and AOFAS scores were 15.19, 4.3, and 24.5 points, respectively. The differences between groups in FAAM ADL score was statistically significant (P = 0.0364). Group 1 showed a global complication rate of 16.67% (n = 5) while group 2 showed 3,3% (n = 1).

CONCLUSION

After the first 30 cases, radiographic, clinical, and functional outcomes substantially improved, and the level of the perioperative complications decreased. The results suggest that the learning curve plateau for performing a percutaneous subcapital osteotomy can be reached after 30 surgeries.

LEVELS OF EVIDENCE

Level III.

Robotic technology: current concepts, operative techniques and emerging uses in unicompartmental knee arthroplasty

Unicompartmental knee arthroplasty (UKA) is associated with improved functional outcomes but reduced implant survivorship compared to total knee arthroplasty (TKA).

Surgeon-controlled errors in component positioning are the most common reason for implant failure in UKA, and low UKA case-volume is associated with poor implant survivorship and earlier time to revision surgery.

Robotic UKA is associated with improved accuracy of achieving the planned femoral and tibial component positioning compared to conventional manual UKA.

Robotic UKA has a learning curve of six operative cases for achieving operative times and surgical team comfort levels comparable to conventional manual UKA, but there is no learning curve effect for accuracy of implant positioning or limb alignment.

Robotic UKA is associated with reduced postoperative pain, decreased opiate analgesia requirements, faster inpatient rehabilitation, and earlier time to hospital discharge compared to conventional manual UKA.

Limitations of robotic UKA include high installation costs, additional radiation exposure with image-based systems, and paucity of studies showing any long-term differences in functional outcomes or implant survivorship compared to conventional manual UKA.

Further clinical studies are required to establish how statistical differences in accuracy of implant positioning between conventional manual UKA and robotic UKA translate to long-term differences in functional outcomes, implant survivorship, complications, and cost-effectiveness.

Cite this article: EFORT Open Rev 2020;5:312-318. DOI: 10.1302/2058-5241.5.190089

How should we evaluate robotics in the operating theatre?

The application of robotics in the operating theatre for knee arthroplasty remains controversial. As with all new technology, the introduction of new systems might be associated with a learning curve. However, guidelines on how to assess the introduction of robotics in the operating theatre are lacking. This systematic review aims to evaluate the current evidence on the learning curve of robot-assisted knee arthroplasty. An extensive literature search of PubMed, Medline, Embase, Web of Science, and Cochrane Library was conducted. Randomized controlled trials, comparative studies, and cohort studies were included. Outcomes assessed included: time required for surgery, stress levels of the surgical team, complications in regard to surgical experience level or time needed for surgery, size prediction of preoperative templating, and alignment according to the number of knee arthroplasties performed. A total of 11 studies met the inclusion criteria. Most were of medium to low quality. The operating time of robot-assisted total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is associated with a learning curve of between six to 20 cases and six to 36 cases respectively. Surgical team stress levels show a learning curve of seven cases in TKA and six cases for UKA. Experience with the robotic systems did not influence implant positioning, preoperative planning, and postoperative complications. Robot-assisted TKA and UKA is associated with a learning curve regarding operating time and surgical team stress levels. Future evaluation of robotics in the operating theatre should include detailed measurement of the various aspects of the total operating time, including total robotic time and time needed for preoperative planning. The prior experience of the surgical team should also be evaluated and reported.

Cite this article: Bone Joint J 2020;102-B(4):407–413.

The learning curve associated with robotic-arm assisted unicompartmental knee arthroplasty

Aims

The primary aim of this study was to determine the surgical team’s learning curve for introducing robotic-arm assisted unicompartmental knee arthroplasty (UKA) into routine surgical practice. The secondary objective was to compare accuracy of implant positioning in conventional jig-based UKA versus robotic-arm assisted UKA.

Patients and Methods

This prospective single-surgeon cohort study included 60 consecutive conventional jig-based UKAs compared with 60 consecutive robotic-arm assisted UKAs for medial compartment knee osteoarthritis. Patients undergoing conventional UKA and robotic-arm assisted UKA were well-matched for baseline characteristics including a mean age of 65.5 years (sd 6.8) vs 64.1 years (sd 8.7), (p = 0.31); a mean body mass index of 27.2 kg.m2 (sd 2.7) vs 28.1 kg.m2 (sd 4.5), (p = 0.25); and gender (27 males: 33 females vs 26 males: 34 females, p = 0.85). Surrogate measures of the learning curve were prospectively collected. These included operative times, the Spielberger State-Trait Anxiety Inventory (STAI) questionnaire to assess preoperative stress levels amongst the surgical team, accuracy of implant positioning, limb alignment, and postoperative complications.

Results

Robotic-arm assisted UKA was associated with a learning curve of six cases for operating time (p < 0.001) and surgical team confidence levels (p < 0.001). Cumulative robotic experience did not affect accuracy of implant positioning (p = 0.52), posterior condylar offset ratio (p = 0.71), posterior tibial slope (p = 0.68), native joint line preservation (p = 0.55), and postoperative limb alignment (p = 0.65). Robotic-arm assisted UKA improved accuracy of femoral (p < 0.001) and tibial (p < 0.001) implant positioning with no additional risk of postoperative complications compared to conventional jig-based UKA.

Conclusion

Robotic-arm assisted UKA was associated with a learning curve of six cases for operating time and surgical team confidence levels but no learning curve for accuracy of implant positioning. Cite this article: Bone Joint J 2018;100-B:1033–42.

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.

Minimally invasive total knee arthroplasty; a pragmatic randomised controlled trial reporting outcomes up to 2 year follow up

BACKGROUND

We present a prospective, randomised, multi-surgeon, controlled trial comparing minimally invasive (MIS) and standard approach total knee arthroplasty (TKA).

METHODS

Participants underwent unilateral TKA. Patients were randomised to Bristol, quadriceps sparing MIS or standard medial parapatellar approaches. Length of stay with secondary outcome measures including knee range of movement, Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC) and American Knee Society Score (KSS) up to 2 years. Radiographic and post operative assessment was blinded.

RESULTS

86 patients (92 knees) participated in the study. Mean operative time between MIS and control groups was 95.5 (95% CI 90.0-101.0) and 94.8 (95% CI 88.2-101.4) minutes respectively. Mean readiness for discharge was shorter in the MIS group 4.5±1.5 (95% CI, 4.1-4.9) days versus 5.9±2.7 (95% CI, 5.1-6.7) days amongst controls (p=0.004). Patients in the MIS group had fewer complications (p=0.003). One patient developed a deep vein thrombosis (DVT) and one required revision surgery, both in the control group. 83 patients completed follow up to 2 years (40 MIS, 43 controls). Range of movement and other outcome measures improved up to 1 year post-operatively with no statistically significant differences between MIS and controls. We found no evidence of radiographic loosening in either group at the 2 year follow up.

CONCLUSIONS

MIS offers reduced length of stay and fewer complications for patients following TKR without evidence of component mal-alignment. Our findings of fewer systemic complications in MIS TKR patients warrant further future study.

LEVEL OF EVIDENCE

Level 1.

Learning curve for new technology?: a nationwide register-based study of 46,363 total knee arthroplasties

BACKGROUND

The risk of early revision is increased for the first patients operatively treated with a newly introduced knee prosthesis. In this study, we explored the learning curves associated with ten knee implant models to determine their effect on early revision risk.

METHODS

We studied register data from all seventy-five surgical units that performed knee arthroplasty in Finland from 1998 to 2007. Of 54,925 patients (66,098 knees), 39,528 patients (46,363 knees) underwent arthroplasty for osteoarthritis of the knee with the ten most common total knee implants and were followed with complete data until December 31, 2010, or the time of death. We used a Cox proportional-hazards regression model for calculating the hazard ratios for early revision for the first fifteen arthroplasties and subsequent increments of numbers of arthroplasties.

RESULTS

We found large differences among knee implants at the introduction with regard to the risk of early revision, as well as for the overall risk of early revision. A learning curve was found for four implant models, while six models did not show a learning effect on the risk of early revision. The survivorship of the studied prostheses showed substantial differences.

CONCLUSIONS

Knee implants have model-specific learning curves and early revision risks. Some models are more difficult to implement than others. The manufacturers should consider the learning effect when designing implants and instrumentation. The surgeons should thoroughly familiarize themselves with the new knee implants before use.

A prospective randomised study of minimally invasive midvastus total knee arthroplasty compared with standard total knee arthroplasty

INTRODUCTION

Proposed advantages of minimally invasive surgery include shorter hospital stay, less blood loss, and a greater range of motion but potential concerns are raised about both prolonged learning curves and a compromise in exposure leading to implant malposition.

PATIENTS AND METHODS

This powered study evaluates the outcomes of 80 patients randomised to have mini-midvastus (MMV) approach or standard medial parapatellar (MPP) approach. Rehabilitation protocols and discharge criteria were standardised. Patients were discharged home directly, capable of safe independent care. Validated outcome measures were recorded post-operatively at intervals up to 1 year. Independent, blinded review of post-operative x-rays was obtained.

RESULTS

Length of stay was similar in the MMV and MPP groups (median 3.73 days vs. 3.75 days). No statistically significant differences were detected in either the demographic data or any intra-operative variable apart from blood loss and incision length. No statistically significant difference in clinical outcome measures (Oxford/Knee Society Scores) or radiographic analysis was observed.

CONCLUSION

The MMV approach does not appear to confer any clinically significant benefit apart from a smaller surgical scar, compared to the MPP surgical technique. Level of evidence I: randomised control trial. R.E.C. 040301.

Introducing a knee endoprosthesis model increases risk of early revision surgery

BACKGROUND

New equipment and techniques often are used in clinical practice, occasionally without evidence of effectiveness and safety.

QUESTIONS/PURPOSES

We asked whether the stage of introduction of an endoprosthesis model for TKA affected the risk of early revision.

METHODS

We studied mandatory registry data from all centers in Finland (n = 69) that performed TKAs for primary osteoarthritis between 1998 and 2004. Of the total of 23,707 patients (28,760 TKAs), 22,551 patients (27,105 TKAs) had a followup of 5 years; we excluded longer followup from the analysis as subsequent revisions might result from wear rather than early technical failures. We used proportional hazards modeling for calculating the hazard ratios for the first 15 operations and subsequent increments of numbers of operations while adjusting for potentially confounding variables.

RESULTS

For the first 15 operations with a new endoprosthesis, the risk was elevated (hazard ratio, 1.48; 95% confidence interval, 1.14-1.91). Absolute risk increase of early revision for the first 15 patients was 1.7% (95% confidence interval, 0.7-2.7). The risk was not increased as the numbers of TKAs incrementally performed increased.

CONCLUSIONS

Our data show an increased risk of early revision surgery for the first patients obtaining a knee endoprosthesis model previously unused in the hospital. Patients should be informed if there is a plan to introduce a new model of endoprosthesis in the hospital and offered the possibility to choose a conventional endoprosthesis instead. Although introducing potentially better endoprostheses is important, there is a need for managed introduction of new technology.

LEVEL OF EVIDENCE

Level I, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Is there a learning curve in foot and ankle surgery?

BACKGROUND

Previous studies of orthopaedic learning curves have largely described the introduction of new techniques to experienced consultants. End points have usually involved technical considerations. A paucity of evidence surrounds foot and ankle surgery. This study investigates the learning curve during a foot and ankle surgeon's first year, defined by functional outcome.

METHODS

150 patients underwent elective foot or ankle surgery during the whole period. Preoperative and 6 month postoperative functional scores were compared between the first and second 6 month groups.

RESULTS

Functional improvement was greater, approaching significance, in the second group (p=0.0605). There was no difference for forefoot cases (p=0.345). Functional improvement was significantly greater in the second group with forefoot cases removed (p=0.0333).

CONCLUSIONS

A learning curve exists in the first year of practice of foot and ankle surgery, demonstrated by functional outcome. This is confined to ankle, hindfoot and midfoot, but not forefoot surgery.

Clinical and radiographic outcomes of Image-Based Computer-Assisted Total Knee Arthroplasty: An Evidence-based Evaluation

Conventional instrumentation systems have limited accuracy in determining the crucial landmarks needed for alignment in total knee arthroplasty (TKA). Given this, the image-based navigation system was introduced to improve the accuracy of implantation of components into the femur and tibia. PubMed, EMBASE, Web of Science, and Evidence-Based Medicine databases were electronically searched to identify eligible studies published until October 2008. A systematic review and meta-analysis of 6 randomized/quasi-randomized controlled trials that compared image-based navigation and conventional techniques was conducted. The operative time was longer in the navigation group in 3 studies. Moreover, there was a higher rate of achieving mechanical leg axis within the range of 3° deviation in patients undergoing navigated TKA. However, all studies between the 2 groups were similar in range of motion, knee scores, and postoperative complication rates at the last follow-up. Overall, these short-term follow-up trials show that there were similar early clinical outcomes between image-based navigation and conventional techniques.

Does minimally invasive surgery improve short-term recovery in total knee arthroplasty?

BACKGROUND

Concerns have been raised regarding minimally invasive surgery (MIS) and its possible effect on postoperative functional recovery, complications, and survival rate after TKA.

QUESTIONS/PURPOSES

We specifically asked whether MIS TKA would be associated with (1) increased operative time, (2) reduced blood loss, (3) shortened hospital stay, (4) faster recovery of ROM, (5) higher knee scores, (6) inferior component positioning, and (7) increased complications.

METHODS

We performed a systematic literature search of randomized controlled trials between minimally invasive and standard approaches in TKA that compared operative time, blood loss, ROM, knee scores, component positioning, and complications. We conducted a systematic review and meta-analysis of 13 trials published from 2007 to 2009 of MIS versus standard TKA.

RESULTS

Patients in the MIS group had longer operating times (10-19 minutes). Mean Knee Society scores were better after MIS than after the standard procedure at 6 and 12 weeks postoperatively, but not after 6 months. Improvement in ROM occurred more rapidly in the MIS group 6 days after TKA but later improvements are not clearly documented. We 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.

CONCLUSIONS

MIS leads to faster recovery than conventional surgery with similar rates of component malalignment but is associated with more frequent delayed wound healing and infections. Potential benefits in long-term survival rate and functional improvement require additional investigation. Level of Evidence Level II, therapeutic study (systematic review). See the Guidelines for Authors for a complete description of levels of evidence.