Excessive femoral torsion is not associated with patellofemoral pain or instability if TKA is functionally aligned and the patella denervated.

PURPOSE: Recent data suggest that individual morphologic factors should be respected to restore preoperative patellofemoral alignment and thus reduce the likelihood of anterior knee pain. The goal of this study was to investigate the effect of excessive femoral torsion (FT) on clinical outcome of TKA. METHODS: Patients who underwent TKA and complete preoperative radiographic evaluation including a long-leg radiograph and CT scan were included. 51 patients showed increased FT of > 20° and were matched for age/sex to 51 controls (FT < 20°). Thirteen patients were lost to follow-up. Thirty-eight matched pairs were compared after a 2 year follow-up clinically (Kujala and patellofemoral score for TKA) and radiographically (FT, frontal leg axis, TT-TG, patellar thickness, patellar tilt, and lateral displacement of patella). Functional alignment of TKA was performed (hybrid-technique). All patellae were denervated but no patella was resurfaced. RESULTS: There was no significant difference between clinical scores two years after surgery between patients with normal and excessive FT (n.s.). Kujala score was 64.3 ± 16.7 versus 64.8 ± 14.4 (n.s.), and patellofemoral score for TKA was 74.3 ± 21 versus 78.5 ± 20.7 (n.s.) for increased FT group and control group, respectively. There was no correlation between preoperative FT and clinical scores. Other radiographic parameters were similar between both groups. No correlations between clinical outcomes and preoperative/postoperative frontal leg axis or total leg axis correction were found (n.s.). CONCLUSION: If the leg axis deformity is corrected to a roughly neutral alignment during cemented TKA, including patellar denervation, then excessive FT was not associated with patellofemoral pain or instability. LEVEL OF EVIDENCE: Prospective comparative study, level II.

Patellofemoral Pain Syndrome Risk Associated with Squats: A Systematic Review.

Patellofemoral pain syndrome (PFPS) is highly prevalent; it can cause severe pain and evolve into progressive functional loss, leading to difficulties performing daily tasks such as climbing and descending stairs and squatting. This systematic review aimed to find evidence, in the literature, of squat movements that can cause or worsen PFPS. This work was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement, and its protocol was registered in PROSPERO (CRD42019128711). From the 6570 collected records, 37 were included. From these 37 articles, 27 present a causal relationship between knee flexion and PFPS, 8 describe a relationship, considering the greater existence of muscle contractions, and one article did not describe this relationship in its results. The main limitations stem from the fact that different studies used different evaluation parameters to compare the force exerted on the patellofemoral joint. Furthermore, most studies are focused on sports populations. After analysing the included works, it was concluded that all squat exercises can cause tension overload in the knee, especially with a knee flexion between 60° and 90° degrees. The main causal/worsening factors of PFPS symptoms are the knee translocation forward the toes (on the same body side) when flexing the knee, and the muscle imbalance between the thigh muscles.

Prevalence of Trochlear Dysplasia and Associations with Patellofemoral Pain and Instability in a Skeletally Mature Population.

BACKGROUND: Patellar instability among adolescents has an incidence of 29 to 43 per 100,000 per year. Trochlear dysplasia has been found in up to 85% of those with recurrent patellar instability. The prevalence of trochlear dysplasia in the general population has not yet been defined. The purpose of the present study was to determine the prevalence of trochlear dysplasia as defined by ultrasound in a skeletally mature population and to characterize associations of trochlear dysplasia with a history of patellofemoral instability or pain. METHODS: Skeletally mature adolescents and parents of patients (≤50 years of age) who had presented to orthopaedic clinics were prospectively enrolled from 2019 to 2020. Those presenting with knee pain, open physes, prior intra-articular fracture, total knee arthroplasty, and syndromic ligamentous laxity or neuromuscular disease were excluded. Information regarding a history of anterior knee pain, patellar instability, and/or surgery was obtained, and an abbreviated Anterior Knee Pain Scale (AKPS) was collected. An AKPS score of ≥4 was considered positive. Bilateral ultrasound of the knee was performed, and the osseous sulcus angle of the trochlea and the trochlear depth were measured. Basic descriptive statistics are reported. RESULTS: One hundred and two patients (203 knees) were studied. The mean sulcus angle was 144.1° ± 6.8°, and the mean trochlear depth was 5.5 ± 1.4 mm. High-grade trochlear dysplasia was defined as the 95th percentile and above, which was shown to be a sulcus angle of ≥154° or a trochlear depth of ≤3 mm for female patients and ≤4 mm for male patients. The prevalence of high-grade trochlear dysplasia was 5.4% based on the sulcus angle and 9.9% based on trochlear depth. Knees with high-grade trochlear dysplasia based on the sulcus angle were 11 times more likely to have had previous patellar instability (p = 0.013). CONCLUSIONS: The prevalence of high-grade trochlear dysplasia in the general population is approximately 10%, and there may be an association with patellar instability. The use of ultrasound to diagnose trochlear dysplasia may prove to be a rapid and useful tool for guiding patient education and treatment decisions. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Dose atrophy of vastus medialis obliquus and vastus lateralis exist in patients with patellofemoral pain syndrome.

BACKGROUND: Whether vastus medialis obliquus atrophy exists in patients with patellofemoral pain syndrome and whether the amount of atrophy differs between the vastus medialis obliquus and vastus lateralis muscles remain unknown. MATERIALS: From June 2016 to March 2019, 61 patients with patellofemoral pain syndrome were retrospectively included in the study group, and an age-, sex-, and body mass index-matched cohort of 61 patients with normal knees was randomly selected as the control group. All enrolled subjects had undergone CT scans in the supine position. The cross-sectional areas of the vastus medialis obliquus and the vastus lateralis muscle in the sections 0, 5, 10, 15, and 20 mm above the upper pole of the patella were measured, and the vastus medialis obliquus/vastus lateralis muscle area ratio was evaluated. RESULTS: In the study group, the vastus medialis obliquus areas and the vastus lateralis muscle areas in the sections that were 0, 5, 10, 15, and 20 mm above the upper pole of the patella were significantly smaller than the respective areas in the control group (P < 0.05). The vastus medialis obliquus/vastus lateralis muscle area ratio was significantly smaller at the upper pole of the patella (the section 0 mm above the upper pole of the patella) than the corresponding ratio in the control group (P < 0.05). No significant difference was noted between the two groups in the sections 5, 10, 15, and 20 mm above the upper pole of the patella (P > 0.05). CONCLUSION: In patients with patellofemoral pain syndrome, vastus medialis obliquus and vastus lateralis muscle atrophy existed in sections 0-20 mm above the upper pole of the patella, compared with normal controls, and atrophy of the vastus medialis obliquus was more evident than that of the vastus lateralis muscle at the upper pole of the patella. These findings support the rationale for the use of general quadriceps exercise combined with vastus medialis obliquus strengthening exercise as part of the rehabilitation programme for the patients with patellofemoral pain syndrome.

Do the Loss of Thigh Muscle Strength and Tibial Malrotation Cause Anterior Knee Pain after Tibia Intramedullary Nailing?

PURPOSE: Anterior knee pain (AKP) is a common complication after tibia intramedullary nailing surgery, but yet the etiology is not fully revealed. Our study had two hypotheses. The first one is "after tibia intramedullary nailing with transtendinous approach, thigh muscles strength decreases and this loss of muscle strength causes AKP." Secondly, "lower extremity rotational profile is affected after tibia intramedullary nailing." Methods. Our study was planned retrospectively and included 40 patients, who underwent tibia intramedullary nailing surgery. Mean follow-up time was 22.5 months. Tegner Lysholm knee scoring scale was applied to evaluate postoperative functional outcomes of all patients. Isometric muscle strengths of bilateral knee extensor and flexor muscle groups were compared with hand-held dynamometer. In addition, bilateral lower extremity Staheli rotational profile angles (foot progression angle (FPA), thigh-foot angle (TFA), and transmalleolar angle (TMA)) were compared. RESULTS: Lysholm knee score was evaluated as excellent in 28 patients. AKP were detected in 15 patients and there was no significant difference between the injured limb with contralateral quadriceps mean muscle strength (injured limb mean (ILM) = 201.97 Newton (N) - contralateral mean (CM) = 205.4 N). However, there was a significant difference (p<0,05) between injured limb with contralateral extremity hamstring mean muscle strength (ILM = 153.2 N- CM=158.95 N). Although there was a significant difference between the two extremities' rotational profile angles, there was no significant correlation between the rotational profile angles and knee pain. CONCLUSION: As a result of our study, AKP appears to be significantly related to the loss of hamstring muscle strength. We suppose that hamstring exercises will gain importance in rehabilitation programs of tibia intramedullary nailing surgery in future.

Association between patellofemoral congruence and patellofemoral chondropathy in patients with anterior knee pain: A T2 mapping knee MRI study.

OBJECTIVES: In this study, the T2 mapping magnetic resonance imaging technique was used to evaluate early cartilage changes associated with patellofemoral alignment and morphology. PATIENTS AND METHODS: Fifty four patients (Study group: 38 females, 16 males) with anterior knee pain and a randomly selected and age-matched 50 controls (Control group; 37 females, 13 males) were compared by two blinded authors in terms of T2 values of the patella medial, lateral facet, and trochlea, Insall-Salvatti index, lateral trochlear inclination angle, patellar tilt angle, sulcus angle, and patella medial and lateral facet lengths. The inter- and intra-observer reliability tests were assessed. RESULTS: The T2 medial patellar facet value, T2 lateral patellar facet value, T2 trochlea value, Visual Analog Scale, tibial tubercle - greater trochanter distance, and patellar tilt angle measure were statistically significantly higher in the study group. CONCLUSION: Based on our study findings, the T2 mapping magnetic resonance imaging (MRI) technique was found to be reliable test that can be used to diagnose early cartilage damage in patients with anterior knee pain. In patients with anterior knee pain, especially with decreased Insall Salvatti index, low lateral trochlear inclination angle, and higher patellar tilt angle, adding a T2 mapping sequence to the standard knee MRI protocol is recommended to help detect early cartilage damage.

[Research progress on the etiology and treatment of patellofemoral pain syndrome].

Patellofemoral pain syndrome (PFPS) is one of the most common diseases that cause pain in the knee joint. At present, there is no specific diagnostic measure. The diagnosis of patellofemoral pain syndrome may be considered when imaging is performed without cartilage, ligament and soft tissue injuries. The etiology includes abnormalities of the patellar motion caused by various anatomical abnormalities, such as abnormal patellar position, increased Q angle, and excessive valgus foot. Dysfunction of the lower extremity muscles such as the imbalance of the four biceps and the dysfunction of the gluteal muscles also play an important role in the development of patellofemoral pain syndrome. At present, there are many treatments, and the exercises of four biceps exercises and hip abductor exercises are aimed at improving the dynamic stability of patella; The muscle patch and the patellar brace mainly reduce the pressure of the patellofemoral joint by improving the patellar trajectory; Foot orthopedic pads are used primarily in patients with valgus feet. After the conservative treatment is ineffective, the patellar lateral retinaculum can be loosened under arthroscopy. Because the patellofemoral pain syndrome is caused by the combined effects of various etiologies, a variety of treatments are helpful to improve the therapeutic effect.

Bone scan usefulness in patients with painful hip or knee prosthesis: 10 situations that can cause pain, other than loosening and infection.

In recent years, with the higher median life expectancy, the number of hip and knee replacements has increased. Clinical examination and morphological studies are essential to evaluate patients with a painful arthroplasty. Nuclear medicine examinations also play an important role, their main usefulness being the exclusion of prosthesis complications. Nevertheless, conventional examinations, namely bone scan and white blood cell scintigraphy, can also identify complications, such as loosening and infection. This study describes the normal and pathologic patterns of a bone scan and exemplifies ten common situations that can cause pain in patients with hip or knee arthroplasty, other than loosening and infection, which can be disclosed on a bone scintigraphy. The ten situations that should be considered and looked for when analysing a bone scan are: referred pain, patellofemoral pain syndrome, fractures, fissures, abscess/haematoma, bone insert behaviour, heterotopic ossification, greater trochanter pseudarthrosis, osteoarthritis extension in a knee with an unicompartmental prosthesis, and systemic disease with bone involvement.

Secondary Patellar Resurfacing as a Rescue Procedure for Persistent Anterior Knee Pain After Primary Total Knee Arthroplasty: Do Our Patients Really Improve?

BACKGROUND: Secondary patellar resurfacing (SPR) is a procedure that can be used in patients with persistent anterior knee pain (AKP) after a primary total knee arthroplasty. The aim of our study was to analyze the clinical and functional outcomes as well as the complications of this procedure and identify predictive factors for a favorable outcome. METHODS: Forty-six patients who underwent SPR for persistent AKP after primary total knee arthroplasty were retrospectively studied. The patient's mean age was 68 years (range, 36-86 years). The average follow-up time after SPR was 74 months (range, 24-197 months). Demographic data, Knee Society Score scale, range of motion, pain improvement (Visual Analogue Scale), overall satisfaction, and complications were recorded. The statistical analysis was performed using STATA tm/SE v10. RESULTS: There was an improvement of the Knee Society scale (from 54 ± 11 to 64 ± 16 points; P < .05). However, in 59% of the cases, there was no pain improvement, and 65% of patients were not satisfied. Four patients showed complications, and in 2 cases, reoperation was necessary. We did not find any preoperative predictive factor for a favorable outcome after SPR. CONCLUSION: Despite improvement of the Knee Society scale, many patients continue with AKP and are dissatisfied with this procedure; therefore, we do not recommend it in this clinical scenario.

No Difference on Quantitative Magnetic Resonance Imaging in Patellofemoral Cartilage Composition Between Patients With Patellofemoral Pain and Healthy Controls.

BACKGROUND: Retropatellar cartilage damage has been suggested as an etiological factor for patellofemoral pain (PFP), a common knee condition among young and physically active individuals. To date, there is no conclusive evidence for an association between cartilage defects and PFP. Nowadays, advanced quantitative magnetic resonance imaging (MRI) techniques enable estimation of cartilage composition. PURPOSE: To investigate differences in patellofemoral cartilage composition between patients with PFP and healthy control subjects using quantitative MRI. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Patients with PFP and healthy control subjects underwent 3.0-T MRI including delayed gadolinium-enhanced MRI of cartilage and T1ρ and T2 mapping. Differences in relaxation times of patellofemoral cartilage were compared between groups by linear regression analyses, adjusted for age, body mass index, sex, sports participation, and time of image acquisition. RESULTS: This case-control study included 64 patients and 70 controls. The mean (±SD) age was 23.2 ± 6.4 years and the mean body mass index was 22.9 ± 3.4 kg/m(2); 56.7% were female. For delayed gadolinium-enhanced MRI of cartilage, the mean T1GD relaxation times of patellar (657.8 vs 669.4 ms) and femoral cartilage (661.6 vs 659.8 ms) did not significantly differ between patients and controls. In addition, no significant difference was found in mean T1ρ relaxation times of patellar (46.9 vs 46.0 ms) and femoral cartilage (50.8 vs 50.2 ms) and mean T2 relaxation times of patellar (33.2 vs 32.9 ms) and femoral cartilage (36.7 vs 36.6 ms) between patients and controls. Analysis of prespecified medial and lateral subregions within the patellofemoral cartilage also revealed no significant differences. CONCLUSION: There was no difference in composition of the patellofemoral cartilage, estimated with multiple quantitative MRI techniques, between patients with PFP and healthy control subjects. However, clinically relevant differences could not be ruled out for T1ρ in the adolescent population. Retropatellar cartilage damage has long been hypothesized as an important factor in the pathogenesis of PFP, but study findings suggest that diminished patellofemoral cartilage composition is not associated with PFP.

Radiofrecuencia pulsada para el tratamiento del síndrome de dolor patelofemoral postraumático / Pulsed radiofrequency for treatment of post-traumatic patellofemoral pain syndrome

El síndrome de dolor patelofemoral puede ser definido como dolor retropatelar o peripatelar resultante de cambios físicos y bioquímicos en la articulación patelofemoral. En ortopedia, las causas más comunes serían el sobreuso, el mal alineamiento patelofemoral y el trauma. Presentamos un caso del uso de radiofrecuencia pulsada selectiva de los nervios patelares, medial y lateral, para el tratamiento del dolor patelofemoral postraumático crónico. La radiofrecuencia pulsada puede ser una opción mínimamente invasiva para el tratamiento del síndrome de dolor patelofemoral postraumático...

Patellofemoral pain syndrome can be defined as retropatellar or peripatellar pain resulting from physical and biochemical changes in the patellofemoral joint. In orthopaedics, the most common causes include overuse, patellofemoral malalignment, and trauma. The case is reported of chronic post-traumatic patellofemoral pain syndrome treated with pulsed radiofrequency of both the medial and lateral patellar nerves. Pulsed radiofrequency might be a minimally invasive option for treatment of post-traumatic patellofemoral pain syndrome...

Knee Pain and Patellofemoral Symptoms in Patients With Cerebral Palsy.

BACKGROUND: Knee pain in cerebral palsy (CP) is associated with increased patellofemoral forces present when walking with flexed knees. In typically developing children, knee pain and patellofemoral dysfunction are associated with obesity, genu valgum, femoral anteversion, and external tibial torsion. These problems are also common in CP, and may contribute to knee problems in this population. The purposes of this study were to define the prevalence of knee pain and patellofemoral dysfunction in children with CP, and to identify physical and gait characteristics (using 3-dimensional gait analysis data) that predispose them to such problems. METHODS: Retrospective review of 121 children with CP, Gross Motor Function Classification System level I to IV, who underwent computerized gait analysis testing. Demographics, range of motion, body mass index and hip, knee, and ankle kinematics were compared between subjects with and without knee pain. RESULTS: Twenty-five of 121 subjects (21%) reported knee pain at the time of testing. Three of 121 subjects (2%) had a history of patellar subluxation/dislocation. Age and sex were significantly related to presence of knee pain. The likelihood of knee pain was almost 5 times higher in females (odds ratio=4.9, [95% confidence interval, 1.8-13.3], P=0.002), with a prevalence of 40% (17/42) in females versus 10% (8/79) in males. The likelihood of knee pain increased with age by approximately 13% per year (odds ratio=1.13, [95% confidence interval, 1.00-1.28], P=0.058). Malignant malalignment syndrome showed a potential relationship to more severe knee pain (P=0.05), which warrants further investigation. Body mass index, pes valgus, and degree of stance knee flexion showed no statistically significant relationships to knee pain (P>0.16). CONCLUSIONS: The prevalence of knee pain in ambulatory patients with CP is approximately 21%. Patellar subluxation (2%) and dislocation are rare in these patients. Knee pain is not always related to crouch, femoral anteversion, external tibial torsion, genu valgum, or pes valgus. Knee pain in these patients is more prevalent in females, and increases with increasing age. LEVEL OF EVIDENCE: Level III-case-control study.

Effect of medial-lateral malpositioning of the femoral component in total knee arthroplasty on anterior knee pain at greater than 8 years of follow-up.

BACKGROUND: The trochlea is often medialized after total knee arthroplasty (TKA) resulting in abnormal patellar tracking, which may lead to anterior knee pain. However, due to the difference in shape of the natural trochlea and the patellar groove of the femoral component, a medialization of the femoral component of 5 mm results in an equal patellar position at 0-30° of flexion. We tested the hypothesis that more medialization of the trochlea results in a higher VAS pain score and lower Kujala anterior knee pain score at midterm follow-up. METHODS: During surgery a special instrument was used to measure the mediolateral position of the natural trochlea and the prosthetic groove in 61 patients between 2004 and 2005. Patient reported outcome measures were used to investigate the clinical results (NRS-pain, NRS-satisfaction, KOOS-PS and Kujala knee score). RESULTS: In total 40 patients were included. The mean follow-up was 8.8 years. A medialization of ≥5 mm resulted in a significantly lower NRS-pain (0.2 vs. 1.4; p=0.004) and higher NRS-satisfaction (9.6 vs. 8.2; p=0.045). Overall clinical results were good; KOOS-PS was 33.9 and Kujala knee score was 72.1. CONCLUSIONS: The present study showed that a more medial position may result in a better postoperative outcome, which can probably be explained by the non-physiological lateral orientation of the trochlear groove in TKA designs. LEVEL OF EVIDENCE: Level III.

Holistic approach to understanding anterior knee pain. Clinical implications.

Anterior knee pain is one of the most frequent reasons for consultation within knee conditions. The aetiology is not well known, which explains the sometimes unpredictable results of its treatment. Normally, when we see a patient in the office with anterior knee pain, we only study and focus on the knee. If we do this, we are making a big mistake. We must not forget to evaluate the pelvis and proximal femur, as well as the psychological factors that modulate the course of the illness. Both the pelvifemoral dysfunction as well as the psychological factors (anxiety, depression, catastrophization and kinesiophobia) must be included in our therapeutic targets of the multidisciplinary treatment of anterior knee pain. We must not only focus on the knee, we must remember to "look up" to fully understand what is happening and be able to solve this difficult problem. The aetiology of anterior knee pain is multifactorial. Therefore, diagnosis and treatment of patellofemoral disorders must be individualized. Our findings stress the importance of tailoring physiotherapy, surgery and psycho-educational interventions to each patient.

Effectiveness of physiotherapy in the treatment of excessive lateral pressure syndrome after anterior cruciate ligament reconstruction - preliminary report.

BACKGROUND: The excessive lateral pressure syndrome is a common complication following anterior cruciate ligament (ACL) reconstruction is. It may lead to premature wear of the articular surfaces of the femur and patella. The aim of the study was to assess the effectiveness of physiotherapy in the treatment of excessive lateral pressure syndrome after ACL reconstruction. MATERIAL AND METHODS: A total of 18 patients (4 women, 14 men) after arthroscopic ACL reconstruction were enrolled (age: 16 -54 years). The patients were randomly divided into two groups: experimental (Group E, 9 people), who attended therapy, and control (group C, 9 people). The distance between the lateral edge of the patella and the lateral condyle of femur was measured with an ultrasound scanner in both extremities. The experimental group patients attended 12 treatment sessions of the.Neurac method. A single session lasted 45 minutes. RESULTS: The baseline examination of both groups showed statistically significant excessive lateral pressure in the operated extremity in relation to the non-operated one in every angular position. At the same time, the quadriceps femoris of the operated extremity was found to be significantly weaker than its counterpart. On completion of the rehabilitation, statistically significant differences in quadriceps strength were recorded in the experimental group compared to the baseline examination while there were no significant differences in the control group. An intergroup comparison did not reveal any significant differences in quadriceps strength. There were also no significant differences in the severity of lateral pressure syndrome before and after the therapy in either group. CONCLUSIONS: 1. Rehabilitation improved quadriceps femoris, strength; it did not, however, decrease excessive lateral pressure syndrome. 2. The rehabilitation programme is not sufficient in conservative treatment of excessive lateral pressure syndrome.

[Denervation of the patella: influence on mid-term results after total knee arthroplasty]. / Retropatellare Denervierung : Einfluss auf die mittelfristigen Ergebnisse von Knietotalendoprothesenimplantationen.

BACKGROUND: The purpose of the study was to determine possible differences in the mid-term results of total knee arthroplasty in patients treated with and without denervation of the patella. PATIENTS AND METHODS: This study included 80 total knee replacements in 71 patients who were treated with total knee replacement, either with (n = 40) or without (n = 40) simultaneous denervation of the patella out of a total population with 122 knee replacements in 100 patients. Comparability of both groups was achieved by applying matching criteria. All patients were reviewed by isokinetic tests, physical and radiological examination. The mean follow-up time was 2.2 years. RESULTS: The mean hospital for special surgery (HSS) score revealed no statistically significant differences between both groups (with denervation 77.9 ± 11.1 and without denervation 77.8 ± 11.0, p = 0.976). The isokinetic torque measurements with low angle velocity (60°/s) indicated slightly higher values during extension (60.2 ± 32.2 Nm versus 55.8 ± 25.2 Nm, p = 0.497) and flexion (52.4 ± 28.3 Nm versus 46.1 ± 22.3 Nm, p = 0.272) movements of the affected knee joint. However, the differences did not reach statistical significance. At high angle velocity (180°/s) no differences could be found between both groups. No cases of postoperative necrosis of the patella were observed. Anterior knee pain after denervation was reported in 6 cases (15 %) compared to 10 cases (25 %) in patients who were treated without denervation (p = 0.402). CONCLUSION: No statistically significant differences could be found between patients with and without denervation of the patella for total knee arthroplasty.

Effect of arthritis in other compartment after unicompartmental arthroplasty.

The purpose of this study is to evaluate the outcome of robotic-assisted (MAKO Surgical Corp.) unicondylar replacement in the treatment for knee osteoarthritis after the initial surgical insult is worn off to evaluate the impact of residual patellofemoral and lateral osteoarthritis on the outcome of medial unicompartmental knee replacement. One hundred and thirty-four patients who underwent uncomplicated 144 robotic-assisted medial unicondylar replacements for knee arthritis were identified and studied. Original radiographs were used to classify severity of patellofemoral and lateral compartmental osteoarthritis in these patients. Severity of patellofemoral and lateral compartmental osteoarthritis was analyzed against Oxford and Knee Society scores and amount of ipsilateral residual knee symptoms at 6 months postoperative period. Preoperative Oxford and Knee Society scores, other comorbidities and long-term disability were studied as confounding variables. We found significant improvement in symptoms and scores in spite of other compartment diseases. Poorer outcome was seen in association with comorbidities and long-term disability but not when radiographic signs of arthritis in the other compartments were present. Six patients required revision of which three had (lateral facet) patellofemoral disease in the original X-rays. In conclusion, there is a higher amount of postoperative retained symptoms, but similar outcome when there is radiographic disease in the other compartments. However, when symptoms are severe enough to necessitate revision, this is due to the lateral facet of patellofemoral compartment and not lateral compartment disease.

No difference in anterior knee pain between a fixed and a mobile posterior stabilized total knee arthroplasty after 7.9 years.

PURPOSE: The presence of anterior knee pain remains one of the major complaints following total knee arthroplasty (TKA). Since the introduction of the mobile TKA, many studies have been performed and only a few show a slight advantage for the mobile. In our short-term follow-up study, we found less anterior knee pain in the posterior stabilized mobile knees compared to the posterior stabilized knees. The concept of self-alignment and the results from our short-term study led us to form the hypothesis that the posterior stabilized mobile knee leads to a lower incidence of anterior knee pain compared to the posterior stabilized fixed knee. This study was designed to see whether this difference remains after 7.9 years in the follow-up. A secondary line of enquiry was to see whether one was superior to the other regarding pain, function, quality of life and survival. METHODS: This current report is a 6-10-year (median 7.9 years) follow-up study of the remaining 69 patients with a cemented three-component TKA for osteoarthritis in a prospective, randomized, double-blinded clinical trial. RESULTS: In the posterior stabilized group, five of the 40 knees (13%) versus five of the 29 posterior stabilized mobile group (17%) experienced anterior knee pain. No differences were observed with regard to ROM, VAS, Oxford 12-item knee questionnaire, SF-36, HSS patella, Kujala or the AKSS score. Patients with anterior knee pain reported more pain, lower levels of the AKSS, HSS patella and the Kujala scores than the patients without anterior knee pain. CONCLUSION: In the current clinical practice, the appearance of anterior knee pain persists as a problem; simply changing to a mobile bearing does not seem to be the solution. The posterior stabilized mobile total knee did not sustain the advantage of less anterior knee pain, compared with the posterior stabilized fixed total knee arthroplasty. LEVEL OF EVIDENCE: Therapeutic study, Level II.

Determinants of anterior knee pain following total knee replacement: a systematic review.

PURPOSE: Anterior knee pain (AKP) following total knee replacement (TKR) is both prevalent and clinically relevant. The purpose of this study was to systematically review the peer-reviewed literature, and to identify and assess the different modifiable and non-modifiable determinants that may be associated with the development of AKP in patients following primary TKR. METHODS: A systematic computerized database search (Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Google Scholar) was performed in January 2012. The quality of the studies was assessed using the GRADE approach. RESULTS: A total of 54 articles met the inclusion criteria. Variables that have been researched with regard to the prevalence of AKP include patient and knee-specific characteristics, prosthetic design, operative technique, treatment of the patella, and time of assessment. A weak correlation with AKP was found for specific retained presurgery gait patterns. A weak recommendation can be given for the use of femoral components with a posterior centre of rotation, resection of Hoffa's fat pad, patellar rim electrocautery, and preventing combined component internal rotation. The correlation between postsurgical AKP and the degree of patellar cartilage wear, tibial component bearing strategies, and patellar resurfacing is inconclusive. Due to substantial heterogeneity of the included studies, no meta-analysis was performed. CONCLUSIONS: No single variable is likely to explain the differences in the reported rates of AKP, although variables leading to abnormal patellofemoral joint loading appear to be of special significance. LEVEL OF EVIDENCE: III.