Patellar Complications Research Articles

Patellar complications in single versus double tunnel medial patellofemoral ligament reconstruction

Hamstring graft fixation on the patellar side during medial patellofemoral ligament (MPFL) reconstruction is usually with transosseous tunnels and can frequently lead to further problems. The aim of our study was to compare and analyse patellar complications in single patellar tunnel versus double tunnel hamstring graft fixation. Twenty-nine knees with MPFL reconstructions (group S) in which the hamstring tendon graft was transfixed using a suspensory fixation method in a single tunnel drilled across the patella were analysed in comparison with 29 knees (group D) with interference fixation of the graft through two tunnels drilled up to a predetermined depth in the patella. Primary outcome measured was any patellar complication like anterior knee pain and patella fracture. Secondary outcomes assessed were future functional instability and failure of reconstruction. Anterior knee pain was noted in six patients in group S, of which three patients had removal of the irritating metalwork on the patella. In all, nine surgical interventions were needed in six patients in this group. Three patients in group D complained of knee pain, but no one in this group needed any further surgical interventions ( p value 0.02). Symptomatic instability requiring revision surgery or realignment surgery was required in two patients in the group S and none in group D. No patellar fractures were seen in either group. Our study showed increasing problems with single tunnel patellar fixation, with more reoperation and failure rates compared to double tunnel fixation. The evidence supports the move towards anatomical double bundle MPFL reconstructions.

Patellofemoral Outcome after Medial Unicompartmental Knee Replacement: A Retrospective Study of 25 Cases

Introduction: Osteoarthritis and impingement, in patellofemoral compartment after partial arthroplasty, have been rarely reported. The purpose of our study was to evaluate outcome at long-term follow-up. Methods: We have reviewed retrospectively twenty-five unicompartmental arthroplasties. The medial parapatellar approach was used in all cases. Patients have been evaluated with regard to patellar impingement and osteoarthritic changes revealed by radiographs. The mean follow-up was 10.4 years. The clinical scoring system of the Knee Society and specific questions regarding patellofemoral symptoms were used for functional outcome. Patellofemoral complications such as osteoarthritis, impingement and the position of the femoral component were diagnosed on X-ray views of the knee. Results: At the final follow-up, fifteen knees revealed lateral patellofemoral osteoarthritis and four knees had patellofemoral impingement. Excepted of two cases, all knees with patella impingement did not revealed degenerative modifications. Anterior pain of the knee was noted more frequently in knees with patellar complications. Patellar impingement was considered the first cause of knee pain, more than knees with degenerative modifications. Only one revision surgery was indicated in front of patellofemoral conflict. The occurrence of patellar impingement depends on the surgical procedure. The anterior position of the femoral component seems to increase the frequency of such complication. Conclusion: Several degenerative modifications may occur in the patello-femoral compartment following partial knee arthroplasty. Patellar impingement and total knee arthritis are the most reported modifications. Functional outcome may be affected progressively when these changes become obvious. Patellar impingement is the major cause of knee pain and needs revision.

Medial patellofemoral ligament reconstruction using a bone groove and a suture anchor at patellar: a safe and firm fixation technique and 3-year follow-up study.

BackgroundGraft fixation is critical to the restoration of the medial patella of femoral ligament function and long-term success. Numerous fixations at the patella have been described, while the complications including patellar fractures, violation of the posterior patella and delay of tendon-to-bone healing remain significant challenges. Here, we describe a safe and firm fixation at the patellar for medial patellofemoral ligament (MPFL) reconstruction and explore the safety angle of drilling the suture anchor at different morphology of the patellar. Moreover, we evaluate the results at a 3-year follow-up.MethodsCombined bone groove and suture anchor fixation at the patella was performed on 26 patients (16 females, 10 males; mean age 26.3 ± 4.7 years) diagnosed with recurrent patellar dislocation. The drilling direction of the suture anchor referred to the safety angle according to the Wiberg type classification. The safety angle was defined as the angle between the drill tunnel and a line that connected the medial and lateral margins of the patella and was established following computed tomography assessment of 117 patients who were diagnosed with patellar dislocation in our hospital according to the Wiberg type classification (I:29, II:65, III:23). X-ray, Lysholm, Kujala and Tegner scores were obtained preoperatively and at the time of final follow-up.ResultsThere were no patellar complications, including fracture and redislocation. Average congruence, patella tilt angles and lateral patella angle were significantly changed (P < 0.01). The Lysholm, Kujala and Tegner scores were significantly increased (P < 0.01). The safe angles of male and female patients according to the patellar Wiberg type classification were less than 45.32 ± 1.76 and 41.20 ± 1.33, 69.74 ± 1.38 and 63.66 ± 1.45 and 84.11 ± 1.67 and 80.26 ± 1.73, respectively.ConclusionsWe achieved encouraging results with this fixation at the patellar. When drilling from Wiberg type I to type III patellar, the suture anchor should be more vertical. When fixing the patellar of female patients, the drilling suture anchor should be more sloping.

Clinical results after treatment for bidirectional patellar subluxation: Minimum 2-years follow-up

BackgroundWe describe the preliminary clinical results of a patellar stabilization technique to treat bidirectional patellar subluxation (BPS). MethodsPatients: six patients (one male, five females; mean age 30.2years) underwent this procedure with a minimum of 24months follow-up. Patients were assessed for clinical instability, patellar complications, and need for revision surgery. Patient functional outcomes were evaluated using the criteria of Crosby and Insall and the Kujala Anterior Knee Pain Scale at the time of final follow-up. Patient satisfaction was assessed using a subjective questionnaire. Operative technique: A semitendinosus tendon autograft is coursed through a transverse tunnel in the distal quadriceps tendon. The medial and lateral aspects of the graft are passed from the quadriceps tendon within subfascial tunnels to the MPFL attachment site and lateral epicondyle, respectively. The graft is fixed in 60° of knee flexion with suture anchors. ResultsSurgery for recurrent instability was performed in one case. There were no cases of infection, quadriceps tendon rupture, or patella fracture. At average follow-up of 29.2months (range, 24 to 38months), outcomes were good to excellent in 4/6 of cases. Kujala scores improved significantly from 33.3 (range, three to 58) preoperatively to 70.8 (range, 39 to 96) postoperatively (p<0.05). 5/6 patients reported being satisfied to completely satisfied with their result. ConclusionPatients undergoing bidirectional patellar stabilization with a single tendon graft showed improved postoperative functional scores. The technique is successful in reducing pain and restoring bidirectional patellar stability at 2-years follow-up.Level of Evidence: IV, retrospective case series.

Total knee implant posterior stabilised by a third condyle: Design evolution and post-operative complications

BackgroundDespite excellent long-term outcomes, posterior stabilisation by a third condyle continues to receive unwarranted criticism regarding patellar complications and instability. HypothesisComplication rates with a tri-condylar posterior-stabilised implant are similar to those with other posterior-stabilised prostheses and have diminished over time due to improvements in prosthesis design. Material and methodsPost-operative complications and revision rates were assessed retrospectively in a prospective cohort of 4189 consecutive patients who had primary total knee arthroplasty (TKA) using a tri-condylar posterior-stabilised implant (Wright-Tornier) and were then followed-up for at least 24 months. The analysis included 2844 knees. The prosthesis generations were HLS1®, n=20; HLS2®, n=220; HLS Evolution®, n=636; HLS Noetos®, n=1373; and HLS KneeTec®, n=595. Complications were compared across generations by applying Fisher's exact test, and survival was compared using the Kaplan-Meier method. ResultsAt last follow-up, there had been 341 (12%) post-operative complications in 306 (10.8%) knees, including 168 (5.9%) related to the implant, 41 (1.4%) infections, and 132 (4.6%) secondary complications unrelated to the implant. Re-operation was required for 200 complications (7%), including 87 (3.1%) consisting in revision of the prosthesis. Implant-related complications were stiffness (n=67, 2.4%), patellar fracture (n=34, 1.2%), patellar clunk syndrome (n=25, 0.9%), patellar loosening (n=3, 0.1%), tibial/femoral loosening (n=15, 0.5%), polyethylene wear (n=3, 0.1%), and implant rupture (n=1, 0.04%). Significant differences across generations were found for stiffness (P<0.0001), patellar fracture (P=0.03), clunk syndrome (P=0.03), and polyethylene wear (P=0.004), whose frequencies declined from one generation to the next. Overall 10-year survival was 92% with no significant difference across generations (P=0.1). DiscussionOutcomes of tri-condylar posterior-stabilised TKA are similar to those obtained using other posterior-stabilised implants. Neither patellar complications nor instability are more common, and improvements in implant design have contributed to correct early flaws. Level of evidenceIV, historical cohort, retrospective assessment of prospectively collected data.

The role of patelloplasty in total knee arthroplasty

Anterior knee pain (AKP) is a frequent complication after total knee arthroplasty (TKA). Patelloplasty, defined as reshaping the patella for optimal tracking in the trochlea, has been proposed to reduce the rate of this complication in patellar retaining implants. Aim of this study was to analyze the available literature regarding the outcomes of patelloplasty and to assess its methodological quality. A comprehensive review of the English literature was performed using the keywords "total knee arthroplasty", "patelloplasty" and "patellaplasty" with no limit regarding the year of publication. All the selected articles were evaluated with the Coleman score. Seven full text articles were retrieved. The initial cohort included 461 knees in the study groups and 465 in the control groups. At an average FU of 70.6months 447 knees were reviewed in the study group and 447 in the control groups. The global rate of AKP after patelloplasty was 11.3% which compared to 7.9% in the patella resurfacing control group. No signs of specific patellar complications due to patelloplasty were reported. Average Coleman score was 66.9. Most of the literature has barely sufficient methodological quality. Patelloplasty aims at reducing patellar thickness and improve its tracking with TKA. This procedure is a safe and easy option with no reported adverse effects. In the included studies, outcome seemed to be superior in comparison with isolated osteophyte removal and denervation with a lower rate of AKP. The included studies, however, report a lower rate of AKP following TKA with patellar resurfacing. Patelloplasty may have the potential to improve the outcome of patellar retaining implants. 4, systematic review.

Conduite à tenir devant une raideur après prothèse totale du genou

A stiff total knee arthroplasty can be caused by a preexisting knee stiffness, technical errors, poor control of pain, postoperative complications and perhaps personal predisposition to postoperative arthrofibrosis and ossifications. Understanding of the mechanism of the stiffness is the first step. However, origin of the stiffness may remain unknown. Revisions for stiffness represent more than 10% of total knee arthroplasties revisions. Treatment options are closed manipulation, surgical or more recently arthroscopic arthrolysis and prosthetic exchange. Manipulation may be performed until 6weeks or two months after healing of the wound and, for this reason, clinical examination one month after the procedure is needed. Arthroscopic arthrolysis requires an experienced surgeon. It provides the best results in stiffness treated between 2 and 6months or a little bit more. After this delay, surgical arthrolysis or prosthetic exchange is indicated. Technical errors are identified by preoperative investigations. CT scan is needed to determine the rotation of both femoral and tibial components. Technical errors require prosthetic exchange unless patella alone is concerned, which is rare. In fact, patellar complications are frequently due to rotational tibial or femoral malpositions. It is difficult to identify some technical errors, such as unbalanced flexion and extension gaps before the revision and, for this reason, it is necessary to be able to perform a prosthetic exchange in any case. All these techniques require an early intensive and prolonged postoperative rehabilitation. Whichever the technique, patients may be disappointed by the result and for this reason careful information is mandatory. Poor results are more frequent when stiffness is unexplained.

Computer Assisted Mechanical Axis and Kinematic TKA

Introduction:Total knee arthroplasty (TKA) has traditionally been and largely continues to be aligned mechanically, that being with a neutral coronal plane mechanical tibiofemoral axis and a joint line orientated at 900 to this axis. Femoral component rotation is set by gap balancing or by externally rotating 30 from any of a number femoral reference lines. This produces a rectangular flexion gap and relaxes patellar tracking. Kinematic alignment (KA) is an alternative technique that aims to restore premorbid alignment, joint orientation and ligament tension. The basic premise for this technique is based on evidence that the medial and lateral femoral condyles consistently equate to cylinders of equal or near equal size and that therefore with a fixed radius, cruciate retaining implant, matched distal femoral, posterior femoral and proximal tibial resections, accounting for bone and cartilage already lost will reproduce the premorbid joint line and restore native premorbid kinematics. Femoral rotation is therefore referenced off the prearthritic posterior condylar axis (PCA) that is on average internally rotated to the AP axis. Kinematic alignment therefore has the potential to challenge patellar tracking, increase patellar load and potentially increase patellar complications.Method:Case control study – level of evidence III-2. Between November 2012 and June 2013 the senior author completed 104 consecutive computer assisted (CAS) kinematically aligned total knee arthroplasties (TKA) with a cruciate retaining, fixed bearing, single radius implant. The results of these surgeries were compared with the results of 91 consecutive CAS mechanically aligned TKA done between November 2011 and October 2012 using the same navigation system and implant Implant sizing and positioning as well as gap measurement and ligament balance was done with computer assistance in all cases. Data was collected prospectively and analysed retrospectively.Results:The Oxford Knee Score improved from 22.2 preoperatively to 42.3 postoperatively in the kinematic group and from 21.5 to 42.1 in the mechanical group. Improvements in the KOOS domains were similar between the two groups except for the sport domain that favoured the kinematic group. Postoperative range of motion was slightly better in the mechanical group. On average there was a difference of femoral component rotation of 4.50. In the kinematic group femoral position was 2.30 internally rotated relative to the AP axis (range 10.50 IR to-6.50 ER) whereas in the mechanical group femoral position was 1.20 externally rotated (range 50 IR to 90 ER. There were six patellofemoral complications in five patients in the kinematic group requiring four additional procedures. Complications included patellar stress fracture / AVN in four patients, one acute patellofemoral dislocation and one chronic patellofemoral dislocation. There were no patellofemoral complications in the mechanical group.Conclusions:The overall results of CAS kinematic and mechanical TKA are similarly excellent but patellofemoral complications occur at an unacceptably high rate with strict kinematic positioning. Patellar resurfacing should be undertaken with caution in kinematic TKA. In the context of kinematic conflict between the posterior condylar and AP axes the femoral component should be externally rotated to reduce load on the patella.

A patient-specific model of total knee arthroplasty to estimate patellar strain: A case study

BackgroundInappropriate patellar cut during total knee arthroplasty can lead to patellar complications due to increased bone strain. In this study, we evaluated patellar bone strain of a patient who had a deeper patellar cut than the recommended. MethodsA patient-specific model based on patient preoperative data was created. The model was decoupled into two levels: knee and patella. The knee model predicted kinematics and forces on the patella during squat movement. The patella model used these values to predict bone strain after total knee arthroplasty. Mechanical properties of the patellar bone were identified with micro-finite element modeling testing of cadaveric samples. The model was validated with a robotic knee simulator and postoperative X-rays. For this patient, we compared the deeper patellar cut depth to the recommended one, and evaluated patellar bone volume with octahedral shear strain above 1%. FindingsModel predictions were consistent with experimental measurements of the robotic knee simulator and postoperative X-rays. Compared to the recommended cut, the deeper cut increased the critical strain bone volume, but by less than 3% of total patellar volume. InterpretationWe thus conclude that the predicted increase in patellar strain should be within an acceptable range, since this patient had no complaints 8months after surgery. This validated patient-specific model will later be used to address other questions on groups of patients, to eventually improve surgical planning and outcome of total knee arthroplasty.

Better joint motion and muscle activity are achieved using kinematic alignment than neutral mechanical alignment in total knee replacement

Inappropriate patellar cut during total knee arthroplasty can lead to patellar complications due to increased bone strain. In this study, we evaluated patellar bone strain of a patient who had a deeper patellar cut than the recommended.A patient-specific model based on patient preoperative data was created. The model was decoupled into two levels: knee and patella. The knee model predicted kinematics and forces on the patella during squat movement. The patella model used these values to predict bone strain after total knee arthroplasty. Mechanical properties of the patellar bone were identified with micro-finite element modeling testing of cadaveric samples. The model was validated with a robotic knee simulator and postoperative X-rays. For this patient, we compared the deeper patellar cut depth to the recommended one, and evaluated patellar bone volume with octahedral shear strain above 1%.Model predictions were consistent with experimental measurements of the robotic knee simulator and postoperative X-rays. Compared to the recommended cut, the deeper cut increased the critical strain bone volume, but by less than 3% of total patellar volume.We thus conclude that the predicted increase in patellar strain should be within an acceptable range, since this patient had no complaints 8 months after surgery. This validated patient-specific model will later be used to address other questions on groups of patients, to eventually improve surgical planning and outcome of total knee arthroplasty.

Causes and rates of revision total knee arthroplasty: Local results from Isfahan, Iran.

Background:Knee replacement is one of the most frequently performed surgical procedures in the world. Local data on revision total knee arthroplasty (TKA) are limited. This study aims to assess the rates and causes of revision TKA in Kashani Hospital (Isfahan, Iran) from 2011 to 2013.Materials and Methods:We assessed all primary TKA and revision TKA procedures performed from 2011 to 2013 for the rate and causes of failures. Demographic data, duration from primary TKA to revision TKA and underlying diagnosis for primary TKA were also assessed.Results:Overall, 353 primary TKA procedures carried out in this period. The overall revisions following primary TKA in this period was 24 cases, indicating a revision burden of 6.8%. The most common cause of revision TKA was infection, which was in 16 cases (44.4%). Other causes included patellar complications, mechanical loosening of both tibia and femur, mechanical loosening of tibia, instability, and periprosthetic fracture. The main revision procedures were all component revision, tibial component revision, isolated tibial insert exchange and patellar tendon repair. The most common revision procedure was two stage all component revision, which was carried out in 13 subjects (36.1%).Conclusion:Local indications for revision TKA are mainly similar to those in other large centers. As compared with other centers, with considering the follow-up time, revision burden is relatively higher in this center.

Avoiding patellar complications in total knee replacement.

Patellofemoral complications are common after total knee replacement (TKR). Leaving the patellar unsurfaced after TKR may lead to complications such as anterior knee pain, and re-operation to surface it. Complications after patellar resurfacing include patellar fracture, aseptic loosening, patellar instability, polyethylene wear, patellar clunk and osteonecrosis. Historically, patellar complications account for one of the larger proportions of causes of failure in TKR, however, with contemporary implant designs, complication rates have decreased. Most remaining failures relate to patellofemoral tracking. Understanding the causes of patellofemoral maltracking is essential to prevent these complications as well as manage them when they occur.

Gender optimized patellar component designs are needed to better match female patellar anatomy.

Avoidance of both over-resection of the native patella, and over-stuffing of the patello-femoral joint are advocated to reduce the risk of patellar complications following patellar resurfacing. Female gender, due to thinner native patella, and use of patellar prostheses from one specific manufacturer that were thicker for comparable diameters than the patellar prostheses from a second manufacturer were hypothesized to be risk factors for these undesirable technical outcomes. A retrospective review was undertaken of 803 consecutive knee replacements, performed by one surgeon, during which the same patellar resurfacing technique had been used, but with two different patellar implant designs. Female gender, and use of one specific design of patella prostheses were associated with both increased risk of patellar over resection to ≤13mm residual patellar thickness, and creation of a patella construct that was thicker than the native patella (p<0.001). Patellar prostheses design can contribute to compromises in surgical technique during patellar resurfacing in TKA in female patients with thinner patellae. Modifications to current patellar prosthesis dimensions may be considered to allow surgeons to more accurately resurface the thinner, native female patella. III.

A simple technique for reconstruction of medial patellofemoral ligament with bone-fascia tunnel fixation at the medial margin of the patella: a 6-year-minimum follow-up study.

BackgroundMedial patellofemoral ligament (MPFL) reconstruction has become an accepted technique to treat patellofemoral instability, and numerous surgical techniques have been described to reconstruct the MPFL. We describe a MPFL reconstruction procedure where bone-fascia tunnel fixation occurs at the medial margin of the patella for recurrent patellar dislocation.ObjectiveMPFL reconstruction is the preferred operative treatment for recurrent patellar dislocation. The purpose of this study was to report a simple technique for reconstruction of medial patellofemoral ligament with bone-fascia tunnel fixation at the medial margin of the patella for recurrent patellar dislocation and to evaluate the results at 6-year-minimum follow-up.MethodsThe study included 65 patients (28 males, 37 females; mean age, 29.4 ± 5.6 years) who underwent MPFL reconstruction using the bone-fascia tunnel fixation at the medial margin of the patella technique and who were followed for a mean duration of 78.5 ± 3.8 months. Objective assessment, Kujala scale, Lysholm score, and Tegner activity score were obtained preoperatively and at the time of final follow-up.ResultsThere were no patellar complications, including redislocation, in the present study. The congruence angle had significant improvement from 19.2° ± 6.3° before surgery to −6.03° ± 0.50° at the last follow-up. The lateral patellar angle had significant improvement from −6.9° ± 3.5° before surgery to 5.1° ± 2.4° at the last follow-up. The patellar tilt angle had significant improvement from 24.5° ± 5.2° before surgery to 12.30° ± 1.90° at the last follow-up. The Kujala score was significantly increased from 52.9 ± 3.2 points preoperatively to 90.1 ± 5.8 points postoperatively (P < 0.05). The mean Lysholm score was significantly increased from 47.2 ± 5.2 to 92.5 ± 6.2 points postoperatively (P < 0.05). The Tegner activity score improved overall from 3.1 ± 0.6 points to 5.8 ± 0.9 points at follow-up.ConclusionWe have done a simple technique where the MPFL is reconstructed safely to avoid patella fracture, anatomically to restore physiological kinematics and stability, and economically to reduce costs with bone-fascia tunnel fixation at the medial margin of the patella.

You Can Do Arthroplasty in a Young Patient, But…

You Can Do Arthroplasty in a Young Patient, But…

Anatomic Reconstruction of the Medial Patellofemoral Ligament in Children and Adolescents Using a Pedicled Quadriceps Tendon Graft

Reconstruction of the medial patellofemoral ligament (MPFL) has recently become a popular procedure for children and adolescents with patellofemoral instability. Nevertheless, high complication rates of up to 26% have been reported. The traditionally used technique requires patellar bone tunnels that may place the proportionately smaller patella at higher risk of fracture. Because of the adjacent physis of the femoral insertion, anatomic reconstruction of the MPFL has the risk of injury to the growth plate. This technical report therefore presents a technique for anatomic reconstruction of the MPFL in a skeletally immature population using a pedicled superficial quadriceps tendon graft, hardware-free patellar graft attachment, and anatomic femoral fixation distal to the femoral physis. The advantages of this technique include avoidance of bony patellar complications, an anatomically truer reconstruction, a single incision, and sparing of the hamstring tendons for reconstruction of any future ligamentous injuries.

The Effect of Infrapatellar Fat Pad Excision on Complications After Minimally Invasive TKA: A Randomized Controlled Trial

The infrapatellar fat pad is one of the structures that obscures exposure in minimally invasive total knee arthroplasty (MIS TKA). Most MIS TKA surgeons (and many surgeons who use other approaches as well) excise the fat pad for better exposure of the knee. There is still controversy about the result of fat pad excision on patella baja, pain, and function. In the setting of a randomized controlled trial, we sought to determine whether infrapatellar fat pad excision during MIS TKA causes (1) patellar tendon shortening (as measured by patella baja); (2) increased anterior knee pain; (3) decreases in the Knee Society Score or functional subscore; or (4) more patella-related complications. We randomized 90 patients undergoing MIS TKA at one institution into two groups. In one group, 45 patients underwent MIS TKA with complete infrapatellar fat pad excision and in the other group, 45 patients received MIS TKA without infrapatellar fat pad excision. The patella was selectively resurfaced in these patients; there was no difference between the groups in terms of the percentage of patients whose patellae were resurfaced. We measured patellar tendon shortening, knee flexion, anterior knee pain, Knee Society Score (KSS), functional subscore, and patellar complications at preoperative and postoperative periods of 6 weeks, 3 months, 6 months, and 1 year; complete followup data were available on 86% of patients (77 of 90) who were enrolled. At the final followup, no significant differences were observed in patellar tendon shortening, KSS, functional subscore, or knee flexion in either group. However, patients with their infrapatellar fat pad excised experienced more anterior knee pain (8.3% versus 0%; p = 0.03; 95% confidence interval, -0.007 to 0.174) at the end of the study. No patellar complications were found in either group. Infrapatellar fat pad excision in MIS TKA resulted in an increasing small percentage of patients with anterior knee pain after surgery. Surgeons should keep the fat pad if excellent exposure can be achieved but resect it if needed to improve exposure during TKA.

Medial Patellofemoral Ligament Reconstruction

Background: Medial patellofemoral ligament (MPFL) reconstruction is a routine procedure for patellar instability. The majority of the techniques require hardware fixation or a bony procedure at the patella. However, most of the complications described in the literature can be attributed to patellar fixation. The “superficial quad technique” uses the superficial slip of the quadriceps tendon as the graft material, which provides a better anatomic match to the native MPFL. Hypothesis: The superficial quad technique provides anatomic patellar fixation without a bony procedure and without patellar complications. Study Design: Case series; Level of evidence, 4. Methods: The study included 32 patients (10 male, 22 female; mean age, 25 years) who underwent MPFL reconstruction using the superficial quad technique and who were followed for a mean duration of 38 months. Objective assessment was performed and Kujala scores were obtained preoperatively and at the time of final follow-up. Results: There were no patellar complications, including redislocation, in the present study. The mean Kujala score improved to 91.25 (range, 73-100) from a preoperative score of 49.31 (range, 23-62). Conclusion: The results were comparable with those of other studies in the literature that used hamstring grafts, but without associated patellar complications. The superficial quad technique uses graft material that is a better anatomic match to the native MPFL. It provides anatomic patellar fixation without a bony procedure.

The efficacy of patellar decompression for improving anterior knee pain following total knee arthroplasty without patellar resurfacing

Anterior knee pain remains common following total knee arthroplasty (TKA). In this study, we evaluated the efficacy of patellar decompression via drilling for the treatment of anterior knee pain following TKA without patellar resurfacing. A prospective cohort study was performed in 271 consecutive patients who underwent primary total knee replacement with patellar decompression (study group, n=131) or without decompression (control group, n=140). The patients were assessed according to the Knee Society rating, clinical anterior knee pain score, and British Orthopaedic Association patient-satisfaction score in each group. Each assessment was performed without the examiner knowing whether the patella had been decompressed. Radiographic evaluations were also performed according to the Knee Society scoring system for functional activity and our own severity grade system for patellofemoral articular change. There were no adverse events following patellar decompression. The overall prevalence of anterior knee pain was not significantly different between groups (p=0.71). However, patients presenting pain over grade II after the operation in the study group were statistically low (p=0.01). The overall postoperative knee scores were higher in the study group, but there were no significant differences between groups (p=0.0731). Analyses of the radiographs revealed similar postoperative outcomes in both groups of knees. As we observed significantly lower rates of anterior knee pain and no patellar complications following patellar decompression via drilling in TKA without patellar resurfacing, we recommend performing patellar decompression in cases of total knee replacement without patellar resurfacing.

Poor short-term outcomes after computer-assisted rotating-platform total knee arthroplasty with a deep-trochlear-groove femoral component: Analysis of 19 patients

Congruent rotating tibial plateaus are designed to minimise wear after total knee arthroplasty (TKA). The Score™ prosthesis has a congruent rotating tibial plateau, a deep trochlear groove, and uses a computer-assisted navigation system for ligament balancing. Although this prosthesis is widely utilized, no accurate data on outcomes are available. The innovative features of the Score™ prosthesis, most notably patellar replacement with a highly constrained femoral component, do not jeopardize implant survival. In a pilot study, we retrospectively evaluated outcomes of 19 patients treated with Score™ knee replacement between February and October 2006 (mean age, 66.8 years; range, 58-82 years). The evaluation criteria were the International Knee Society (IKS) scores and prosthesis survival rate estimated using Kaplan-Meier plots with failure defined as revision need to change the prosthesis. Mean follow-up was 35.3 months. The IKS knee score increased from 27.4 (5-60) preoperatively to 81.4 (45-99) at last follow-up (P<0.0001). Mean mechanical axis was 181.2° (180-186°), with 16 between 180° and 183°. Revision surgery was required in five cases (for patellar complications with combined motion-range limitation in flexion (<90°) and extension (5-20°) in three cases, isolated motion-range limitation in one case, and recurvatum deformity with instability in one case). Prosthesis survival was 82% (73-91%) after 24 months and 65% (51-78%) after 44 months. The deep trochlear groove femoral component resulted in patellar complications, which were the most common reasons for revision surgery, together with motion-range limitation and instability possibly related to improper use of the navigation system. This small retrospective case-series study showed an unusually low prosthesis survival rate probably related to the implant design. We no longer use the Score™ prosthesis, despite the availability of a dedicated navigation system, and we recommend careful monitoring of patients who have this prosthesis. Level IV, retrospective study.