The early clinical outcome of minimally invasive quadriceps-sparing total knee arthroplasty: report of a 2-year follow-up

The results of 32 minimally invasive quadriceps-sparing (Q-S) total knee arthroplasties were compared with those of a matched group of 35 standard total knee arthroplasties. The patients were prospectively followed for a mean of 24 months (range, 18-28 months). The Q-S group was significantly quicker in regaining quadriceps strength and knee flexion and had less pain during the first 2 postoperative weeks. The Knee Society scores showed no significant difference at 6 weeks, 1 year, and last visit. There were 9 outliers in the Q-S group, none in the standard group. The tourniquet time was significantly longer in the Q-S group. Patients in the Q-S group were 100% satisfied about the incision. The Q-S technique showed better and faster recovery, but there were more outliers and bone injuries during surgery, and this coupled with length of tourniquet time were the major disadvantages in our early experience.     

Minimally invasive total knee arthroplasty

Currently, minimally invasive total knee arthroplasty is defined as an incision length of < 14 cm. However, the length of the incision is not the primary influence on potential postoperative benefits to the patient and should not be the only characteristic of the minimally invasive approach for knee arthroplasty. Some other factors that should also be included in this definition are: 1. The amount of soft-tissue dissection (including muscle, ligament, and capsular damage). 2. Patellar retraction or eversion. 3. Tibiofemoral dislocation. Minimally invasive surgery should not be considered to be a cosmetic procedure but rather one that addresses patients' concerns with regard to postoperative pain and slow rehabilitation. Standard total knee arthroplasties provide pain relief, but returning to activities of daily living remains a challenge for some individuals, who may take several weeks to recover. Several studies have demonstrated long-term success (at more than ten years) of standard total knee arthroplasties. However, many patients remain unsatisfied with the results of the surgery. In a study of functional limitations of patients with a Knee Society score of > or = 90 points after total knee arthroplasty, only 35% of patients stated that they had no limitations. This finding was highlighted in a study by Dickstein et al., in which one-third of the elderly patients who underwent knee replacement were unhappy with the outcome at six and twelve months postoperatively. Although many surgeons utilize objective functional scoring systems to evaluate outcome, it is likely that the criteria for a successful result of total knee arthroplasty differ between the patient and the surgeon. This was evident in a report by Bullens et al., who concluded that surgeons are more satisfied with the results of total knee arthroplasty than are their patients. Trousdale et al. showed that, in addition to concerns about long-term functional outcome, patients' major concerns were postoperative pain and the time required for recovery. Patients undergoing total knee arthroplasty have specific functional goals, such as climbing stairs, squatting, kneeling, and returning to some level of low-impact sports after surgery. Our clinical investigations demonstrated that the minimally invasive surgical approach reduces hospital stays, decreases postoperative pain, and decreases rehabilitation needs as well as enables patients to return to normal function more quickly. It is important for surgeons to take an evolutionary, rather than a revolutionary, approach when performing minimally invasive total knee arthroplasty. The surgeon should downsize incisions progressively to prevent severe damage to the quadriceps mechanism. Extensive open exposure, prolonged patellar eversion, and dislocation of the tibiofemoral joint should evolve into a vastus medialis muscle split with patellar subluxation, retraction but not dislocation of the patella, and avoidance of gross dislocation of the tibiofemoral joint. Developing the techniques of minimally invasive total knee arthroplasty may be difficult and time-consuming, but patient benefits and satisfaction should outweigh the extra effort required. These changes require well-designed clinical studies to further document their effectiveness.     

A midvastus muscle-splitting approach for total knee arthroplasty

This study presents a modification of the medial parapatellar surgical approach for total knee arthroplasty. This approach separates the vastus mediatis muscle in the direction of its fibers beginning at the superior pole of the patella. One hundred eighteen consecutive total knee arthroplasty cases, performed by a single surgeon, were randomized prospectively to receive a medial parapatellar or midvastus muscle-splitting surgical approach. The frequency of lateral retinacular releases was recorded, patellar tilt and translation were measured, and quadriceps strength was tested. The midvastus muscle-splitting approach provided excellent exposure to all knees. Patellar stability and quadriceps strength were equivalent for the two approaches. It is concluded that the midvastus muscle-splitting approach is an efficacious alternative to the medial parapatellar approach for primary total knee arthroplasties.     

Minimally invasive total knee arthroplasty compared with traditional total knee arthroplasty. Assessment of the learning curve and the postoperative recuperative period

BACKGROUND: There is disagreement about whether so-called minimally invasive approaches result in faster recovery following total knee arthroplasty. It is also unknown whether patients are exposed to excess risk during the surgeon's learning curve. We hypothesized that a minimally invasive quadriceps-sparing approach to total knee arthroplasty would allow earlier clinical recovery but would require longer operative times and compromise component alignment during the learning period compared with a traditional medial parapatellar approach. METHODS: The first 100 minimally invasive total knee arthroplasties done by a single high-volume arthroplasty surgeon were compared with his previous fifty procedures performed through a medial parapatellar approach, with respect to operative times, implant alignment, and clinical outcomes. Radiographic end points and operative times for the minimally invasive group were evaluated against increasing surgical experience, in order to characterize the learning curve. RESULTS: Overall, the minimally invasive approach took significantly longer to perform, on the average, than a medial parapatellar approach (86.3 and 78.9 minutes, respectively; p=0.01); this was the result of especially long operative times in the first twenty-five patients in the minimally invasive group (mean, 102.5 minutes). After the first twenty-five minimally invasive operations, no significant difference in the operative times was detected between the groups. The first twenty-five minimally invasive procedures had significantly less patellar resection accuracy (p<0.001) and significantly more patellar tilt than the last twenty-five (p=0.006). Other end points for implant alignment, including the frequency of radiographic outliers, were not different between the minimally invasive and traditional groups. The patients who had the minimally invasive approach demonstrated significantly better clinical outcomes with respect to the length of hospital stay (p<0.0001), need for inpatient rehabilitation after discharge (p<0.001), narcotic usage at two and six weeks postoperatively (p=0.001 and p=0.01, respectively), and the need for assistive devices to walk at two weeks postoperatively (p=0.025). CONCLUSIONS: A quadriceps-sparing minimally invasive approach seems to facilitate recovery, but a substantial learning curve (fifty procedures in the hands of a high-volume arthroplasty surgeon) may be required. If this experience is typical, the learning curve may be unacceptably long for a low-volume arthroplasty surgeon.     

Minimally invasive total knee replacement through a mini-midvastus incision: an outcome study

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.     

A comparison of the vastus splitting and median parapatellar approaches in total knee arthroplasty.

This prospective randomized study was undertaken to evaluate the vastus splitting approach as an alternative to the median parapatellar approach in primary total knee arthroplasty. Fifty-one knees in 42 patients were randomized preoperatively. Clinical parameters were evaluated preoperatively and at regular postoperative intervals. Electromyography was performed preoperatively and postoperatively to evaluate each approach relative to its effect on the innervation of the quadriceps mechanism. There were no significant preoperative differences. Postoperatively, there were no significant differences regarding strength, range of motion, knee scores, tourniquet time, proprioception, or patellar replacement. There were significantly more lateral releases performed and greater blood loss in the patients in the parapatellar group. The results of all preoperative electromyograms were normal, as were all of the results of postoperative electromyograms in the patients in the parapatellar group. However, the results of nine of 21 (43%) of the electromyograms performed postoperatively on patients who had the vastus splitting approach were abnormal. Significantly fewer lateral releases were performed and there was less blood loss in the patients in the vastus group. However, the postoperative electromyographic results revealed neurologic injuries in the vastus medialis muscle that only were present after the vastus splitting approach. The clinical significance of denervation of the vastus medialis muscle by the vastus approach remains to be determined by longer term clinical and electromyographic studies.     

The outcome of total knee arthroplasty in obese patients

BACKGROUND: Evidence linking increased body weight to osteoarthritis of the knee and the high prevalence of obesity underscore the importance of defining the outcome of total knee arthroplasty in obese patients. The purpose of this study was to compare the clinical and radiographic results of total knee arthroplasties performed in obese patients with those of total knee arthroplasties performed in nonobese patients. METHODS: Clinical and radiographic data on seventy-eight total knee arthroplasties in sixty-eight obese patients were compared with data on a matched group of nonobese patients. The analysis was also performed after stratification of the obese group for the degree of obesity. All patients had the same prosthesis. The clinical data that were analyzed included the Knee Society objective and functional scores, patellofemoral symptoms, activity level, and complications. RESULTS: The percentage of knees with a Knee Society score of > or =80 points at an average of eighty months was 88% in the obese group, which was significantly lower than the 99% rate in the nonobese group at the same time. The morbidly obese subgroup had a significantly higher revision rate than did the nonobese group (p = 0.02). CONCLUSIONS: The results of the present study suggest that any degree of obesity, defined as a body mass index of > or =30, has a negative effect on the outcome of total knee replacement.     

Minimally invasive total knee replacement through a mini midvastus approach: a comparative study

Between September 2001 and September 2002, forty consecutive minimally invasive total knee replacements were done. A modified midvastus approach was used and the patella was subluxed, but not everted. We compared the results of this group with an age-matched and sex-matched cohort of total knee replacements done between June 2000 and September 2001 with a standard technique. A posterior-stabilized knee (Genesis II) was used in both groups. Patients achieved motion considerably faster in the minimally invasive total knee replacement group. Mean flexion for minimally invasive total knee replacement at 6 and 12 weeks was 114 degrees (range, 90-132 degrees ) and 122 degrees (range, 103-135 degrees ) respectively, compared with 95 degrees (range, 65-125 degrees ) and 110 degrees (range, 80-125 degrees ) for the control group. Improved range of motion was also seen at one year postoperatively. The average range of motion at one year postoperatively in the minimally invasive total knee replacement was 125 degrees (range, 110-135 degrees ) compared with 116 degrees (range, 95-130 degrees ) in the Control Group. Postoperative Knee Society scores were also higher in the minimally invasive total knee replacement group. There was no difference in xray alignment. There were no infections, extensor mechanism or neurovascular complications. The mini midvastus approach without patella eversion combined with a small incision was associated with a more rapid functional recovery and improved range of motion in total knee replacement without compromising implant positioning.     

Component alignment after minimally invasive total knee arthroplasty: results of the first 100 cases performed

It has been suggested that minimally invasive total knee arthroplasties increase the risk of component malalignment. Results during the period of initial learning curve on component malalignment are relatively unknown but should be addressed. This study reports the component alignment data of the first 100 minimally invasive total knee arthroplasties performed by a single surgeon from the very start of a community-based practice immediately after fellowship training. The results indicate that the initial learning curve produces results comparable to reported results of standard total knee arthroplasties.     

Progressive quadriceps incision during minimally invasive surgery for total knee arthroplasty: the effect on early postoperative ambulation

A prospective series of 114 consecutive minimally invasive surgeries for total knee arthroplasty was performed using the quadriceps-sparing approach at the beginning. Intraoperatively, when the knee was in 45 degrees to 60 degrees of flexion, lateral patella subluxation was evaluated. A progressive quadriceps tendon incision with a 1-cm increment was applied if the patella could not be completely slid. The mean follow-up time was 24 months. There were 3 groups according to the length of quadriceps incision: group A (17 knees) had no or 1-cm quadriceps incision; group B (60 knees) had 2-cm incision; and group C (37 knees) had 3-cm incision. The average operative time, blood loss, pain score, preoperative range of motion and postoperative range of motion at 2 weeks, 6 weeks, 12 weeks, and 3 months were not significantly different among groups. Patient ability for early ambulation (sitting, knee straightening, standing, and walking) was indifferent between groups A and B; however, this was significantly delayed in group C. In conclusion, minimally invasive surgery for total knee arthroplasty with 2-cm quadriceps incision or strict quadriceps-sparing approach provided no difference on early ambulation.     

Subvastus versus medial parapatellar approach in total knee arthroplasty

The subvastus approach for total knee replacement was compared with the standard medial parapatellar approach in terms of postoperative knee scores and quadriceps strength. Two groups of patients with similar characteristics were formed: the first group consisted of 12 knees of 9 patients who were implanted via the medial parapatellar approach, and for the second group the subvastus approach was used in 10 knees of 10 patients. The groups' knee scores and quadriceps strength were compared preoperatively and postoperatively at week 6, months 3 and 6. The knee scores improved similarly in both groups, but the change was more pronounced in the subvastus group. Quadriceps strength was greater in the subvastus group at postoperative week 6, but there was no significant difference between the groups in months 3 and 6. It was concluded that although the subvastus approach offers greater quadriceps strength in the early postoperative period, it has no significant advantage in this aspect over the medial parapatellar approach.     

Comparison of primary total hip arthroplasties performed with a minimally invasive technique or a standard technique: a prospective and randomized study

The purpose of this prospective randomized study was to compare the early results of primary total hip arthroplasties performed with a minimally invasive technique or a standard technique. A consecutive series of 70 patients who underwent primary bilateral simultaneous total hip arthroplasties was studied. All procedures were performed through a posterolateral approach. Operative times and duration of hemovac drains were significantly shorter in the group with a minimally invasive technique (P < .05). However, there was a risk of infection when using this technique. There were no any late transfusions in any of our patients postdischarge. This minimally invasive technique did not offer any advantages because the results were not different, and in our hands, it increased our infection rate.     

Total knee arthroplasty in limbs affected by poliomyelitis

BACKGROUND: Little information is available regarding the results and complications of total knee arthroplasty in limbs affected by poliomyelitis with severe knee degeneration. METHODS: We performed a retrospective chart and radiograph review of patients with a history of poliomyelitis involving a limb that subsequently underwent primary total knee arthroplasty between 1970 and 2000. Sixteen total knee arthroplasties were performed in limbs affected by poliomyelitis in fifteen patients. Eleven patients were followed for a minimum of two years, one (two knees) died before the minimum two-year follow-up could be completed, and three were followed for less than two years. No patient was lost to follow-up. RESULTS: There were two periprosthetic fractures, one peroneal nerve palsy, one avulsion of the patellar tendon, and four cases of recurrent instability. These complications were related to the poor bone quality, valgus deformity, patella baja, poor musculature, and attenuated soft tissues commonly found in knees affected by poliomyelitis. Knee Society pain and knee scores were improved postoperatively for all nine knees with a two-year follow-up that had had at least antigravity quadriceps strength prior to surgery. However, Knee Society function scores remained at 0 or worsened for six of the eleven knees followed for at least two years, including those with less than antigravity strength, and four of the nine knees with at least antigravity strength. None of the prostheses loosened. CONCLUSIONS: Pain and knee scores improved following total knee arthroplasty in patients with a history of poliomyelitis and antigravity quadriceps strength, but there was less pain relief in patients with less than antigravity quadriceps strength. Recurrence of instability and progressive functional deterioration is possible in all knees affected by poliomyelitis that have undergone total knee replacement, but they appear to occur more commonly in more severely affected knees.     

The trivector approach for minimally invasive total knee arthroplasty: A technical note

One of the main criticisms of minimally invasive approaches in total knee arthroplasty has been their poor adaptability in cases of major deformity or stiffness of the knee joint. When they are used in such cases, excessive soft-tissue tension is needed to provide appropriate joint exposure. Here, we describe the "mini trivector approach," which has become our standard approach for total knee replacement because it permits us to enlarge the indication for minimally or less invasive total knee replacement to many knees where quad sparing, a subvastus approach, or a mini quad or mini midvastus snip may not be sufficient to achieve correct exposure. It consists of a limited double snip of the VMO and the quadriceps tendon that reduces tension on the extensor mechanism and allows easier verticalization of the patella as well as good joint exposure.     

Total knee arthroplasty in patients with poliomyelitis

Between 1991 and 2001, 17 primary total knee arthroplasties were performed in 15 patients with limbs affected by poliomyelitis. Eight patients had a constrained condylar knee design, 8 a posterior stabilized design, and 1 a hinged design. Mean follow-up was 41.5 months. The mean Knee Society knee score improved from 45 preoperatively to 87 postoperative. Knee stability was obtained in all patients, including 4 patients with less than antigravity quadriceps strength. Radiologic evaluation showed satisfactory alignment with no signs of loosening. Complications included 1 case of deep venous thrombosis and 2 knees that required a manipulation for stiffness. Pain relief, functional improvement, and knee stability can be achieved after constrained total knee arthroplasty in patients with poliomyelitis despite impaired quadriceps strength, and osseous and soft tissue abnormalities.     

Mini-midvastus versus mini-medial parapatellar approach in total knee arthroplasty: a prospective, randomized study

Introduction

To date, no English literature has evaluated the short-term results of the mini-medial parapatellar approach compared with the mini-midvastus approach. This prospective, randomized study was performed to compare the short-term results of total knee arthroplasty using either a mini-midvastus or a mini-medial parapatellar approach.

Patients and methods

We reported the clinical and radiological results of 89 patients who had primary total knee arthroplasties with minimally invasive techniques using either a mini-midvastus or a mini-medial parapatellar approach. The mini-midvastus approach was used on 45 patients (group I) and a mini-medial parapatellar approach on 44 patients (group II). Skin incision length, tourniquet time, incidence of lateral retinacular release, total blood loss, straight leg raising time, visual analogy scale score, alignment of the knee, component position, and complication of each group were examined. Knee Society scores, range of motion were compared at 7 days, 6 weeks, 3 months, and 6 months postoperatively.

Results

The mean tourniquet time was 68 min in group I, significantly longer than 56 min for group II. However, comparisons of postoperative knee scores and function scores between both approaches did not yield a significant difference in outcome. No significant difference was found with respect to total blood loss, visual analogy scale score, straight-leg-raising test, range of motion or radiographic findings.

Conclusion

Based on these results, we believe that the early results are similar between mini-midvastus and mini-medial parapatellar approach, ultimately the selection of the surgical approach will depend on the surgeon’s experience and preference.     

Functional and radiological outcome after total knee replacement performed with mini-midvastus or conventional arthrotomy: controlled randomised trial

The results of minimally invasive techniques used for total knee replacement are controversial. Despite reported advantages such as faster recovery, there are some concerns regarding component positioning. We compared mini-midvastus versus medial parapatellar arthrotomy with respect to component position and functional results. We included 70 osteoarthritis total knee replacement patients in our study. Patients were randomised for the approach. We recorded Knee Society scores before and after the surgery and radiological component position. Patients were followed up to 12 weeks after the surgery. We found that the mini-midvastus approach was associated with better Knee Society scores six weeks after surgery; after 12 weeks the difference was not statistically significant. We found no difference related to the approach in radiological component position. The mini-midvastus approach is associated with faster recovery and reproduces the same accuracy in component positioning as the medial parapatellar approach.     

Minimally Invasive Total Knee Arthroplasty Improves Early Knee Strength But Not Functional Performance : A Randomized Controlled Trial

A prospective, randomized investigation compared early clinical outcomes of total knee arthroplasty (TKA) using conventional or minimally invasive surgical (MIS) approaches (n = 44). Outcome measures included isometric quadriceps and hamstrings strength, quadriceps activation, functional performance, knee pain, active knee range of motion, muscle mass, the Short Form-36, and Western Ontario and McMaster University Osteoarthritis Index, assessed preoperatively and 4 and 12 weeks after TKA. Four weeks after TKA, the MIS group had greater hamstring strength (P = .02) and quadriceps strength (P = .07), which did not translate to differences in other outcomes. At 12 weeks, there were no clinically meaningful differences between groups on any measure. Although MIS may lead to faster recovery of strength in patients undergoing TKA, there was no benefit on longer-term recovery of strength or functional performance.     

Muscle torques in total knee arthroplasty with subvastus and parapatellar approaches

The current study was designed to compare muscle torques when using the subvastus and parapatellar approaches for unilateral total knee arthroplasty. Twelve female patients had unilateral total knee arthroplasty with the subvastus approach from January 1997 to June 1998. The historic control group consisted of 16 female patients who had unilateral total knee arthroplasty with the parapatellar approach from July 1994 to January 1997. Six and 12 months after surgery, a Cybex dynamometer was used to measure isometric and isokinetic muscle strength. Two parameters were used to compare the two approaches, the first parameter was the difference in peak torque between the surgically treated knee and the baseline value for the healthy knee, and the second parameter was the hamstring to quadriceps peak-torque ratio, again using the value for the healthy knee as baseline. The subvastus approach resulted in an initial higher peak torque in the quadriceps 6 months after surgery, but this difference became insignificant 12 months postoperative. Using the subvastus approach, the hamstring to quadriceps peak-torque ratio reached the normal range (0.50-0.80) sooner than was the case using the parapatellar approach. There is a phenomenon of cross adaptation of the untreated knee to the surgically treated knee, and knees operated on by the subvastus approach showed functional recovery at an earlier date than those operated on by the parapatellar approach.     

Quadriceps muscle atrophy and long-term recovery after knee ligamentous injury

The aim of the study was to clarify if atrophy of the quadriceps muscle was in itself related to clinical and radiological long-term outcome of primary knee ligament surgery. At Tampere University Central Hospital clinical and radiological reexamination was performed in 61 patients on an average 40 months after primary operation of acute knee ligament injury. The study group consisted of 26 patients having clear quadriceps muscle atrophy in the injured knee at the follow-up. Thirty four patients, having equal circumference of the thighs, served as controls. One patient was excluded. The groups did not differ significantly from each other in respect to age, sex, physical activity, type of ligament injury, meniscectomy, and follow-up time. In clinical reexamination the patients with quadriceps atrophy were placed significantly more often in groups of fair or poor healing than the patients with normal quadriceps muscle, and they had also more posttraumatic osteoarthritic changes in the injured knee. According to this study it seems that quadriceps muscle atrophy plays an important role as a poor prognostic factor of knee ligament injuries being thus a good target for efforts to stop the continuous deterioration of the injured knee.