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.     

Strength and voluntary activation of quadriceps femoris muscle in total knee arthroplasty with midvastus and subvastus approaches

To determine and compare the influence of 2 different approaches on quadriceps femoris muscle function in total knee arthroplasty (TKA), 20 patients (14 women, 6 men) with bilateral knee osteoarthritis underwent a 1-stage bilateral TKA. Surgical approaches (subvastus, midvastus) were performed by a random selection. Measurements of quadriceps voluntary activation and maximal voluntary contraction were estimated by a twitch interpolation technique before, 3 and 6 months after TKA. Knee pain was quantified by the Lewis Score. There was no difference between the 2 approaches at 3 and 6 months after TKA with regard to maximal voluntary contraction (P = 0.84, F = 0.041) and voluntary activation (P = .863, F = 0.031). In the subvastus group was a significantly higher knee pain until 6 months after surgery (P = .02). The subvastus approach for TKA does not provide any advantages compared with the midvastus approach with respect to the quadriceps femoris muscle strength in the early postoperative period. Furthermore, the subvastus approach caused significantly more pain postoperatively.     

Comparison of early postoperative rehabilitation outcome following total knee arthroplasty using different surgical approaches and instrumentation

PURPOSE: To assess early postoperative rehabilitation outcome following computer-assisted total knee arthroplasty (TKA) or standard instrumentation TKA using a medial parapatellar or subvastus approach. METHODS: A prospective controlled trial of 70 consecutive patients undergoing TKA with a low contact stress rotating platform prosthesis was conducted. Patients were randomised to receive surgery with either computer navigation or standard instrumentation. A medial parapatellar or subvastus approach was used according to the surgeons' preference. Outcome measures included preoperative knee function, intra-operative factors, and postoperative rehabilitation. RESULTS: Duration of surgery was significantly longer when using computer navigation; however, operating time decreased with greater experience. A higher incidence and duration of early postoperative quadriceps dysfunction was associated with computer-assisted TKA through the medial parapatellar approach than through the subvastus approach or TKA performed with standard instrumentation. No patient who received surgery through the subvastus approach had a lag of more than 20 degrees, at 48 hours postoperatively, regardless of the instrumentation used. CONCLUSION: Computer-assisted TKA through a medial parapatellar approach was associated with delayed recovery of the quadriceps during early postoperative rehabilitation. This was due to the additional quadriceps dissection required to place the femoral tracking array. The subvastus approach is therefore recommended for computer-assisted TKA.     

Subvastus approach for total knee arthroplasty

The indications for the subvastus approach in total knee arthroplasty are the same for a medial parapatellar approach in the appropriately selected patient. The subvastus approach does not violate the quadriceps mechanism, reduces the need for lateral retinacular release, preserves the patella blood supply, and, with our modifications, can be used in most cases.     

Evaluation of total knee arthroplasty using isokinetic testing

Although total knee arthroplasty (TKA) has been studied extensively, objective muscle testing has not been reported. Isokinetic testing of 68 patients with degenerative joint disease scheduled for unilateral TKA revealed that marked muscular deficits in flexion and extension were present preoperatively in the involved knee. Postoperatively, hamstring peak-torque values were able to attain strength levels of the uninvolved knee within the period of seven to 12 months after surgery, whereas the quadriceps mechanism still showed a residual deficit at two years follow-up evaluation. In addition, the ratio of flexion to extension peak torques in the operated knee returned to normal values as the quadriceps mechanism was rehabilitated. A comprehensive evaluation system consisting of Cybex II isokinetic testing, gait mat analysis, and the Hospital for Special Surgery knee rating scale is also presented. Isokinetic testing correlated well with gait analysis. Patients with a nearly balanced quadriceps-to-hamstring ratio walked with a more symmetrical gait pattern. The knee rating scale was less reliable in assessing functional outcome. Functional testing and evaluation at the authors' institution has provided an important source of objective information that allows better planning and evaluation of TKAs. These isokinetic studies enable more critical planning of the rehabilitation program. Hamstring or quadricep exercises may be emphasized as required. The authors conclude that a balanced hamstring to quadriceps mechanism is needed for resumption of normal gait.     

Surgical Approaches in Total Knee Arthroplasty: A Meta-Analysis Comparing the Midvastus and Subvastus to the Medial Peripatellar Approach

Subvastus, midvastus and medial parapatellar approaches are the most popular approaches in total knee arthroplasty (TKA). However, the superior approach in TKA still remains controversial. We therefore conducted a meta-analysis to quantitatively compare the midvastus and subvastus approaches to the medial parapatellar approach in TKA. A total of 32 randomized controlled trials (RCTs) with 2451 TKAs in 2129 patients were included in this study. The meta-analysis suggested that, when compared with the medial parapatellar approach, the midvastus approach showed better outcomes in pain and knee range of motion at postoperative 1–2 weeks but also was associated with longer operative time; the subvastus approach showed better outcomes in knee range of motion at postoperative 1 week, straight leg raise and lateral retinacular release.     

Surgical approaches in mini-incision total knee arthroplasty

Mini-incision total knee arthroplasty can be accomplished through versions of exposures used in standard total knee arthroplasty. Modifications of the medial parapatellar, subvastus, and midvastus approaches are presented, and potential advantages and disadvantages of each approach are reviewed. When making the transition to smaller incisions and arthrotomies, the medial parapatellar seems to be the most versatile. The ability to do a total knee arthroplasty through a mini incision, and ultimately the success of the procedure, will depend on appropriate patient selection.     

Systematic Review of Medial Parapatellar and Subvastus Approaches in Total Knee Arthroplasty

This systematic review was performed to compare the outcomes of the medial parapatellar and subvastus surgical approaches for total knee arthroplasty. Five studies, published between 1993 and 2001 met the inclusion quality standards for the review. The methodological quality of most studies was poor, and they were not sufficiently homogenous for meta-analysis. We found that the evidence was insufficient to demonstrate a clinical or statistically significant difference between the medial parapatellar and subvastus approaches to total knee arthroplasty across all outcomes. Further trials with robust methodology, objective and functional outcome measures, and follow-up beyond 6 to 12 months are required.     

Comparison of the vastus-splitting and median parapatellar approaches for primary total knee arthroplasty: a prospective, randomized study

BACKGROUND: A vastus-splitting approach for total knee arthroplasty has been advocated to preserve function of the extensor mechanism and to decrease the prevalence of lateral release. Critics have claimed that there is greater blood loss and compromised exposure in large patients who are managed with this approach. The purpose of the present study was to compare vastus-splitting and median parapatellar approaches for primary total knee arthroplasty. METHODS: Forty-two consecutive patients (fifty-one knees) undergoing primary total knee arthroplasty were randomized to treatment with a median parapatellar or vastus-splitting approach. The interval of the vastus muscle split was marked with radiopaque vascular clips. Surgical data, functional parameters, and preoperative and postoperative electromyograms were assessed. RESULTS: Early (six-month) and intermediate-term (five-year) follow-up showed no differences in functional parameters, tourniquet time, or the frequency of patellar resurfacing. Significantly more lateral releases (p < 0.01) and greater blood loss (p = 0.03) occurred in the median parapatellar group. Nine (43%) of twenty-one knees in the vastus-splitting group had abnormal electromyographic findings at six months postoperatively, whereas all patients in the median parapatellar group had normal findings. Seven knees with abnormal electromyographic findings at six months had normal findings when restudied at five years; in each of these knees, the vastus split had been developed bluntly. The other two knees with abnormal findings at six months had had sharp dissection for the muscle split. Both of these knees had chronic changes, one with changes indicative of reinnervation and the other with ongoing denervation, but neither demonstrated functional compromise. CONCLUSIONS: The vastus-splitting approach offers a viable alternative to the median parapatellar approach for primary total knee arthroplasty that reduces the need for lateral retinacular release without impairment of quadriceps function. Electromyographic abnormalities in the quadriceps muscle have no functional consequence and most likely represent reversible neurapraxic injury that may be avoided by blunt dissection in the vastus medialis muscle.     

Comparison of the subvastus and paramedian surgical approaches in bilateral knee arthroplasty

A prospective randomized study was performed on 20 patients undergoing one-stage bilateral knee arthroplasty. One knee was exposed using a standard median parapatellar arthrotomy and the other knee with a subvastus arthrotomy. All patients underwent quantitative strength testing before surgery and at I week, I month, and 3 months after surgery. The knees were also evaluated for range of motion, and patients, who were blinded as to the approach used, completed questionnaires at each evaluation period as to their preference, if any, regarding knee pain and level of function. There was no difference in the range of motion between knees exposed with the paramedian or subvastus arthrotomy at any time period. The subvastus knees demonstrated significantly greater strength at the 1-week and 1-month intervals, but there was no strength difference at the 3-month interval. There were more lateral releases performed in the paramedium knees, and three minor complications were related to the subvastus approach. Patients who expressed a preference chose the subvastus knee 4: 1 over the paramedian knee. The subvastus approach offers a reasonable alternative to the paramedian arthrotomy and preserves greater quadriceps strength in the early postoperative period.     

Comparing outcomes of medial parapatellar and subvastus approaches in total knee arthroplasty: a randomized controlled trial

The medial parapatellar (MP) approach in total knee arthroplasty is more common, but the subvastus (SV) approach is less insulting to the quadriceps. Whether the SV approach affords better outcomes was investigated using 90 participants with knee osteoarthritis, randomized to receive either SV or MP approaches and followed for 18 months. The primary outcome was the American Knee Society Score (AKSS); secondary outcomes included pain, knee range, quadriceps lag, Oxford Knee Score, 3-m timed "Up and Go" test, days to straight leg raise, surgeon perceived difficulty, operation duration, and length of stay. Analysis (n = 76) revealed no significant difference in AKSS (P = .076) or other outcomes, except the following: AKSS Functional scores at 12 and 18 months, favoring the MP (P = .032 and P = .028 respectively); surgeon's perceived difficulty, favoring the MP (P = .001); and days to straight leg raise, favoring the SV (P = .044). This study found that the SV approach offers no clinical benefit over the MP approach.     

Isokinetic Strength Testing of Minimally Invasive Total Knee Arthroplasty Recovery

Fifty patients underwent isokinetic muscle strength testing before surgery and at 6 weeks, 3 months, 6 months, and 1 year after unilateral total knee arthroplasty using the minisubvastus surgical technique. Quadriceps muscle strength returned to preoperative levels by 3 months postoperatively and was 17% stronger at 6 months and 30% stronger at 1 year than preoperative levels (P < .05). At 1 year, the quadriceps strength of the involved knee was equivalent to that of the uninvolved knee (P = .81). When the entire study population was subdivided by age, weight, sex, and the presence of arthritis in the uninvolved knee, each subgroup still had equivalent quadriceps strength between the involved and uninvolved knees. This prospective study demonstrated that the minisubvastus total knee arthroplasty technique led to a more rapid and more complete recovery of muscle strength than has been previously demonstrated after total knee arthroplasty with a medial parapatellar arthrotomy.     

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.     

Is Minimally Invasive Surgery in Total Knee Arthroplasty Really Minimally Invasive Surgery?

Minimization of soft-tissue damage is one of the primary purposes behind the application of minimally invasive surgery (MIS) in total knee arthroplasty (TKA). A consecutive series of 147 TKAs were enrolled in the present study, with 96 MIS-TKAs using 11 quadriceps-sparing, 46 subvastus, 32 midvastus, and 7 parapatellar approaches and 51 conventional TKAs using 22 subvastus, 9 midvastus, and 20 parapatellar approaches. Serum levels of creatinine phosphokinase, myoglobin, aldolase, lactate dehydrogenase, glutamic oxaloacetic transaminase, and creatinine were measured on postoperative days 0, 1, 2, 4, 7, and 14. Postoperative rising index (RI) was expressed as a proportion of the preoperative value. When RIs were compared between MIS-TKA and conventional TKA, no significant differences were found for any enzymes. Interestingly, the midvastus approach displayed the highest RIs for creatinine phosphokinase and myoglobin between the 4 vastus-splitting approaches. Consequently, degree of muscle damage was equivalent between MIS-TKA and conventional TKA, whereas types of vastus-splitting approach appeared closely related to muscle damage.     

A comparison of patellar vascularity between the medial parapatellar and subvastus approaches in total knee arthroplasty

A complication of total knee arthroplasty is patellar avascular necrosis. Surgical approaches for total knee arthroplasty include the medial parapatellar approach (MPa) and, less commonly, the subvastus approach (SVa). The argument that SVa retains better patellar vascularity than the MPa was investigated on 20 participants, (SVa, n = 10; MPa, n = 10) 18 months postoperatively. Outcomes were a radionuclide bone imaging technique, a new bone vascularity scale, and an anterior knee pain numerical assessment scale. Results indicated no significant difference between groups on imaging (P = .935), the components of the bone vascularity scale, or anterior knee pain (P > .999). The SVa appears to offer no benefit over the MPa in terms of patellar vascularity or anterior knee pain.     

Subvastus approach for total knee arthroplasty: a prospective, randomized, and observer-blinded trial

A prospective, randomized, and blinded trial was conducted with 89 consecutive primary knee arthroplasties comparing standard medial parapatellar arthrotomy with the subvastus approach. All patients received the same prosthesis (Insall-Burstein II) inserted by one surgeon using an identical technique with the only difference being the approach. The parapatellar approach (group I) was used in 43 knees, and in the remaining 46 knees the subvastus approach (group II) was used. Assessment revealed significantly earlier return of straight-leg raise (3.2 days vs 5.8 days, P <.001), lower consumption of opiates in the first week (78 mg vs 102 mg, P <.001), less blood loss (527 mL vs 748 mL, P <.001), and greater knee flexion at 1 week (78 degrees vs 55 degrees, P <.001) in group II (subvastus approach). The subvastus approach offers early advantages over the standard parapatellar arthrotomy. It preserves the integrity of the vastus medialis and peripatellar plexus of vessels. We advise its wider use in primary total knee arthroplasty.     

Comparing Outcomes of Medial Parapatellar and Subvastus Approaches in Total Knee Arthroplasty : A Randomized Controlled Trial

The medial parapatellar (MP) approach in total knee arthroplasty is more common, but the subvastus (SV) approach is less insulting to the quadriceps. Whether the SV approach affords better outcomes was investigated using 90 participants with knee osteoarthritis, randomized to receive either SV or MP approaches and followed for 18 months. The primary outcome was the American Knee Society Score (AKSS); secondary outcomes included pain, knee range, quadriceps lag, Oxford Knee Score, 3-m timed “Up and Go” test, days to straight leg raise, surgeon perceived difficulty, operation duration, and length of stay. Analysis (n = 76) revealed no significant difference in AKSS (P = .076) or other outcomes, except the following: AKSS Functional scores at 12 and 18 months, favoring the MP (P = .032 and P = .028 respectively); surgeon's perceived difficulty, favoring the MP (P = .001); and days to straight leg raise, favoring the SV (P = .044). This study found that the SV approach offers no clinical benefit over the MP approach.     

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.     

Subvastus and medial parapatellar approaches in total knee arthroplasty

This retrospective study compared the outcome of two consecutive groups of patients having primary total knee arthroplasty. The arthroplasties were performed in the first group (169 arthroplasties in 143 patients) from 1988 to 1992 using a medial parapatellar approach, and in the second group (167 arthroplasties in 148 patients) from 1992 to 1996 using a subvastus approach. The patient outcomes were evaluated at 6 months, and were based on clinical and radiographic measures, occurrence of intraoperative lateral retinacular release, and incidence of postoperative patellar subluxation. There were no significant differences between the two groups for range of motion, Knee Society knee and function scores, and stair climbing ability. The patella tracked centrally in significantly more knees with the subvastus approach (139 of 167 knees, 83%) than with the parapatellar approach (107 of 169 knees, 63%). There were significantly fewer knees in the subvastus group requiring a lateral retinacular release (62 of 167 knees, 37%), compared with the parapatellar group (113 of 169 knees, 67%). The authors concluded that the subvastus approach led to improved patellar tracking and stability. Although the surgical and rehabilitative protocols were identical for both groups, the results may have been affected by changing circumstances during the 9-year period of the study.     

Outcome of subvastus approach in elderly nonobese patients undergoing bilateral simultaneous total knee arthroplasty: A randomized controlled study

Background:

Subvastus approach in total knee arthroplasty (TKA) spares the quadriceps and may assist in faster rehabilitation. The present randomised controlled study was conducted to determine if the subvastus approach results in early recovery, faster mobilization, shorter hospital stay, and improved function.

Materials and Methods:

100 patients undergoing simultaneous bilateral TKA were randomized into two groups: subvastus group and medial parapatellar group. The patients were assessed clinically using VAS, time to straight leg raise, ability to stand with walker, ability to use a commode chair, ability to climb stairs, flexion at discharge, and day of discharge. Perioperative blood loss and duration of surgery were also compared. The patient were kept on same pain management and physiotherapy protocol. The evaluation was done at day 0,1,3 and at discharge. Statistical analyses tested the null hypotheses of no differences in patients treated with either group at 95% significance level (P < 0.05).

Results:

The VAS score was significantly lower in subvastus group on day 1 and day 3. Also mean hospital stay was 2.04 days less in subvastus group. Patients with subvastus approach were able to perform straight leg raising 0.44 days earlier. Though time to stand with walker was same for both groups, the ability to use commode chair, and climb stairs was significantly early (P < 0.05) in the subvastus group. The average flexion at the time of discharge in subvastus and parapatellar group were 100.8 and 96.8°, respectively. The mean perioperative blood loss in subvastus group and parapatellar group were 343 ml and 372 ml, respectively. Average surgical time required for subvastus approach and parapatellar approach were 108.5 and 94.3 min, respectively.

Conclusions:

Subvastus approach produce appreciably less pain and faster mobilization due to lesser insult to quadriceps, thus assisting in early rehabilitation, shorter hospital stay, less expenditure, and more patient satisfaction.