Aims. The aim of this study was to compare the incidence of anterior knee pain after antegrade tibial nailing using suprapatellar and infrapatellar surgical approaches. Patients and Methods. A total of 95 patients with a tibial fracture requiring an intramedullary nail were randomized to treatment using a supra- or infrapatellar approach. Anterior knee pain was assessed at four and six months, and one year postoperatively, using the Aberdeen Weightbearing Test – Knee (AWT-K) score and a visual analogue scale (VAS) score for pain. The AWT-K is an objective patient-reported outcome measure that uses weight transmitted through the knee when kneeling as a surrogate for anterior knee pain. Results. A total of 53 patients were randomized to a suprapatellar approach and 42 to an infrapatellar approach. AWT-K results showed a greater mean proportion of weight transmitted through the injured leg compared with the uninjured leg when kneeling in the suprapatellar group compared with the infrapatellar group at all timepoints at all follow-up visits. This reached significance at four months for all timepoints except 30 seconds. It also reached significance at six months at 0 seconds, and for one year at 60 seconds. Conclusion. The suprapatellar surgical approach for antegrade tibial nailing is associated with less anterior knee pain postoperatively compared with the infrapatellar approach. Cite this article: Bone Joint J 2019;101-B:1138–1143

Objectives. To assess the effectiveness of a modified tibial tubercle osteotomy as a treatment for arthroscopically diagnosed chondromalacia patellae. Methods. A total of 47 consecutive patients (51 knees) with arthroscopically proven chondromalacia, who had failed conservative management, underwent a modified Fulkerson tibial tubercle osteotomy. The mean age was 34.4 years (19.6 to 52.2). Pre-operatively, none of the patients exhibited signs of patellar maltracking or instability in association with their anterior knee pain. The minimum follow-up for the study was five years (mean 72.6 months (62 to 118)), with only one patient lost to follow-up. Results. A total of 50 knees were reviewed. At final follow-up, the Kujala knee score improved from 39.2 (12 to 63) pre-operatively to 57.7 (16 to 89) post-operatively (p < 0.001). The visual analogue pain score improved from 7.8 (4 to 10) pre-operatively to 5.0 (0 to 10) post-operatively. Overall patient satisfaction with good or excellent results was 72%. Patients with the lowest pre-operative Kujala score benefitted the most. Older patients benefited less than younger ones. The outcome was independent of the grade of chondromalacia. Six patients required screw removal. There were no major complications. Conclusions. We conclude that this modification of the Fulkerson procedure is a safe and useful operation to treat anterior knee pain in well aligned patellofemoral joints due to chondromalacia patellae in adults, when conservative measures have failed

Our purpose was to evaluate the incidence of anterior knee pain after ACL reconstruction and the associated affecting factors. The study assessed 50 ACL reconstructed knees: 29 males and 21 females. The age at surgery was from 14 to 39 years old, with 23.7 years old on the average. The ACL injury was unilateral in all cases, and the normal side was defined as the control. We treated chronic ACL-deficient knees by reconstruction of the ligament through a limited arthrotomy using one-third of the patellar tendon (BTB) with the Kennedy LAD as a graft. Anterior knee pain was classified into 4 group: absent, trace-mild, moderate, and severe. We evaluated the height of the patella, knee extension strength, anterior laxity, leg rotation, Lysholm score, and loss of extension. Anterior laxity and leg rotation were measured by a three-dimensional analyzer. Ten of the fifty knees (20%) had anterior knee pain. Knee extension strength (reconstructed side/control side) was 71.1% in the cases with anterior knee pain and 84.2% in the cases without anterior knee pain. A significant difference was found between these values. Regarding leg rotation, 4 knees showed normal leg rotation (physiological screw home movement) in the cases with anterior knee pain, compared to 31 knees in the cases without anterior knee pain. There was a significant difference in the incidence of anterior knee pain between the cases with normal leg rotation and the cases without. Other factors failed to show any significant correlation. In this study, knee extension strength and leg rotation had a correlation with anterior knee pain

Aims. It is not clear whether anterior knee pain and osteoarthritis (OA) of the patellofemoral joint (PFJ) are contraindications to medial unicompartmental knee arthroplasty (UKA). Our aim was to investigate the long-term outcome of a consecutive series of patients, some of whom had anterior knee pain and PFJ OA managed with UKA. Patients and Methods. We assessed the ten-year functional outcomes and 15-year implant survival of 805 knees (677 patients) following medial mobile-bearing UKA. The intra-operative status of the PFJ was documented and, with the exception of bone loss with grooving to the lateral side, neither the clinical or radiological state of the PFJ nor the presence of anterior knee pain were considered a contraindication. The impact of radiographic findings and anterior knee pain was studied in a subgroup of 100 knees (91 patients). Results. There was no relationship between functional outcomes, at a mean of ten years, or 15-year implant survival, and pre-operative anterior knee pain, or the presence or degree of cartilage loss documented intra-operatively at the medial patella or trochlea, or radiographic evidence of OA in the medial side of the PFJ. In 6% of cases there was full thickness cartilage loss on the lateral side of the patella. In these cases, the overall ten-year function and 15-year survival was similar to those without cartilage loss; however they had slightly more difficulty with descending stairs. Radiographic signs of OA seen in the lateral part of the PFJ were not associated with a definite compromise in functional outcome or implant survival. Conclusion. Severe damage to the lateral side of the PFJ with bone loss and grooving remains a contraindication to mobile-bearing UKA. Less severe damage to the lateral side of the PFJ and damage to the medial side, however severe, does not compromise the overall function or survival, so should not be considered to be a contraindication. However, if a patient does have full thickness cartilage loss on the lateral side of the PFJ they may have a slight compromise in their ability to descend stairs. Pre-operative anterior knee pain also does not compromise the functional outcome or survival and should not be considered to be a contraindication. Cite this article: Bone Joint J 2017;99-B:632–9

Introduction. Up to 15 % of patients report anterior knee pain (AKP) after a total knee arthroplasty (TKA). The correlation of radiographic patellar measurements and post-operative AKP remains controversial. The purpose of this study was to determine whether any radiographic measurements can predict anterior knee pain after TKA. Methods. We performed a retrospective analysis of data on 343 patients who underwent a primary unilateral TKA between 2009–2012 at a single institution. Post-operative radiographs were evaluated with standing anteroposterior, lateral, and merchant views. Radiographic assessment was performed to assess posterior offset, Insall Salvati ratio, Blackburne, PP angle, Patella thickness, Congruence angle, Patella tilt, and patella displacement. Clinical function was assessed by the Kujala anterior knee pain scale at a minimum of 5 years. Patients were asked if they currently had anterior knee pain post-operatively by responding “yes” or “no.” There were 264 females and 79 males; the mean age at surgery was 64.2 ± 9.7 (range, 42–92 years) years; the mean BMI 31±5.8 kg/m. 2. (range, 18.8–49 kg/m. 2. ). Results. Of the 343 patients, 46 patients (13.4%) patients suffered persistent AKP at a minimum 5 years follow-up. Radiographic measurements were performed. Although we had large variations in congruence angle, patellar tilt and patellar displacement, these variations had no correlation with anterior knee pain (p=0.885). We were not able to detect statistical significance among clinical outcome Kujala score and patient reported AKP (p=0.713) at minimum 5 year follow-up. Discussion. Persistent anterior knee pain is troubling to patients and surgeons. Clinicians often get concerned when they see variability in these radiographic findings. Our findings suggest that variations in radiographic parameters do not predict anterior knee pain following total knee replacement surgery. For figures, tables, or references, please contact authors directly

There is a recognised incidence of anterior knee pain following Anterior Cruciate Ligament (ACL) reconstruction using a patella tendon autograft. This study examined two group of patients both pre ACL ligament reconstruction and post ACL reconstruction using patella tendon grafts to define if anterior knee pain is a result of patella tendon harvest or a primary consequence of an ACL injury. The two groups of patients were best matched for age, sex and physical activity. The pre-operative group of twenty-five patients had a confirmed ACL rupture and exhibited symptoms of instability requiring an ACL reconstruction. The operative group of twenty-five patients were a minimum of a year post operation. The graft was harvested by an open procedure and the graft bone blocks were secured with interference screws. The patients’ anterior knee pain score was assessed using the Shelbourne scoring system that evaluates knee function in relation to anterior knee pain using five parameters. The maximum score is 100. The scores were compared using the unpaired student test. There was no significant age difference between the two groups, preoperative group age 32. 2 years (range 22 to 46) and postoperative age 34. 8years (range 19 to 48). The mean anterior knee pain score for the preoperative group was 71. 6 (49 to 100), the postoperative group was 77. 7 (45 to 100), this was not significantly different. We found no significant difference in knee function due to anterior knee pain between the two groups. Studies have shown significant anterior knee pain following hamstring reconstruction (Spicer). This study shows anterior knee pain in the ACL deficient knee is present prior to surgery. We conclude that patella tendon autografts produce no significant incidence of anterior knee pain post surgery

Anterior knee pain is a frequent complaint of dissatisfied total knee arthroplasty patients. We hypothesize that the need to use the extensor mechanism to stabilise the knee during activity is a cause of anterior knee pain. Studies have shown that TKA patients often walk with a “quadriceps avoidance” gait, which may explain the phenomenon of anterior knee pain. Most TKA prostheses are designed to allow AP motion. This feature in knee implant design is to prevent the “kinematic conflict” that was predicted with the crossed four-bar-link model of knee motion, which holds that progressive posterior contact of the femur on the tibia (rollback) with flexion was obligatory for knee range of motion. It has been stated that preventing this motion overly “constrained” the knee and could lead to loosening and wear. Paradoxical motion has been seen with video fluoroscopy in knees after TKA. This motion is an anterior translation of the femur on the tibia early in knee flexion and is called paradoxical because it occurs opposite to the expected rollback. In fact, paradoxical motion is a consequence of the “unconstrained” articulation of the femoral component on the tibial component. During gait, just after heel strike as the foot is assuming a flat position on the floor, there is a significant vector of force from posterior to anterior. This vector has been calculated as 33% of body weight for walking at normal speed and could lead to a significant displacement of the femur forward on the tibia. It is countered by 1) the slope of the proximal tibia; 2) the articulation of the femur in the concavity of the tibial (with the firmly attached meniscus that deepens the concavity) on the medial side; and 3) the body mass vector combined with that of the contracting quadriceps. If a total knee prosthesis allows the femur to move forward, the posterior-to-anterior force just after heel strike acts to move the femur forward on the tibia (paradoxical motion). The patient, in an attempt to stabilise the knee, uses increased quadriceps contraction to prevent the forward motion of the femur. The forces required are significant and are not only found in the patella-femoral articulation but all through the retinaculum that covers the anterior part of the femur. As the extensor mechanism tires, patients begin using a quadriceps avoidance gait to adapt to the weakening extensor, and after a period of activity, the stress on the retinaculum leads to pain. AP stability can be improved through implant design by preventing AP motion through conformity of the femoral and tibial components. We have used a medially conforming ball-in-socket prosthesis as a revision component for patients with anterior knee pain, and have achieved resolution of the pain. Patients demonstrate a “posterior sag” at approximately 20 degrees of flexion (the degree of flexion that has the maximum posterior-to-anterior force during gait). When treated with a brace appropriate for stabilisation of the knee after PCL reconstruction, patients experienced a marked decrease in symptoms and this predicts a good result from revision surgery

Excessive foot pronation has been considered to be related to anterior knee pain. We undertook a prospective study to test the hypothesis that exertional anterior knee pain is related to the static and dynamic parameters of foot pronation. Two weeks before beginning basic training lasting for 14 weeks, 473 infantry recruits were enrolled into the study and underwent two-dimensional measurement of their subtalar joint displacement angle during walking on a treadmill. Of the 405 soldiers who finished the training 61 (15%) developed exertional anterior knee pain. No consistent association was found between the incidence of anterior knee pain and any of the parameters of foot pronation. While a statistically significant association was found between anterior knee pain and pronation velocity (left foot, p = 0.05; right foot, p = 0.007), the relationship was contradictory for the right and left foot. Our study does not support the hypothesis that anterior knee pain is related to excessive foot pronation

Purpose: A relationship between vastus medialis oblique (VMO) strength and anterior pain and disability has been suggested. A biomechanical protocol was used to access the deficiency of the quadriceps muscles in patients with anterior knee pain. Methods and Results: A biomechanical evaluation was conducted on 54 patients with anterior knee pain (34 females and 20 males). All patient x-rays were normal through interpretation by a blinded radiologist. A Kistler force plate, a VICON motion analysis system and surface electromyography were used to quantify biomechanical function during isometric, walking and squatting exercises. For 42 of the 54 (78%) subjects, during isometric and walking exercises we observed that activation of the VMO, rectus femoris (RF) and vastus lateralis (VL) muscles of the symptomatic leg was not significantly different from those of the asymptomatic leg (p< 0.01). However, for 31 patients (57%) during the eccentric phase of the squat exercises, the symptomatic leg presented with high activation of VL compared to VMO and RF (p< 0.01). During the concentric phase, 45 patients (83%) presented with higher activation of the VL compared to the VMO. Conclusion: VMO activity during squatting for the symptomatic patient with anterior knee pain leg differs fundamentally during walking and isometric exercise compared to squatting tasks. Moreover, the relative contribution of the VL compared to the VMO during the eccentric phase of the squat exercises was different to those recorded during the concentric phase. Therefore, we suggest that maximal isometric and or isokinetic exercises are not sufficient to access the quadriceps function in relation to anterior knee pain. A thorough biomechanical assessment, including functional testing to reproduce the patient’s pain and locate the nature of the symptoms is suggested

Aim: To assess the prevalence of anterior knee pain after intramedullary nailing of the tibia and its socioeconomic impact. Methods: A retrospective, study of 251 consecutive tibial intramedullary nailings in 248 patients, aged less than 60 years at the time of injury. The minimum follow-up period was five years and the patients were assessed using a questionnaire and the Lysholm knee score. Results: The mean follow-up was 7.9 years. Anterior knee sensory disturbance was reported by 58% of patients. Anterior knee pain (AKP) was reported by 47%. This interfered with activities of daily living in 37%, work in 36% and sport in 57%. Pain on kneeling was mild in 54%, moderate in 34% and severe 12%. AKP improved with time in 73% patients and became worse in 4%. The Lysholm score rated 41% knees as excellent, 19% as good, 26% as fair and 14% as poor. Eighty-six percent of the patients returned to work. The presence of anterior knee pain prevented return to previous work in 10%. The type of work performed before and after injury respectively were; sedentary 26%/29%, walking-based 20%/27%, manual 38%/37%, heavy manual 16%/7%. Conclusions: Anterior knee pain persisted in 47% of patients after intramedullary nailing of the tibia. There was some decrease in symptoms with time and the majority of patients were able to return to work. However, anterior knee pain caused a significant disability in a small number and all patients should be warned of this problem before this type of surgery

Aims: Anterior knee pain is a common complaint of mixed aetiology, and in many cases no demonstrable cause is identified. For patients with persistant anterior knee pain, tibial tubercle transfer (TTT) can be a surgical option. The aim of this study is to assess the effectiveness of TTT for chronic anterior knee pain resistant to conservative treatment. Method: All patients with arthroscopically proven Chondromalacia patellae (CMP) without clinical evidence of patella instability, who have failed to respond to conservative treatment such as physiotherapy were included in the trial. They underwent TTT with a modified Fulkerson technique and then routine post-operative care with a cricket pad splint for 2–4 weeks. Pre and post-operative scores were obtained using a Kujala patello-femoral score, a visual analogue score for pain and a patient satisfaction score. The Outerbridge grading was used to score the severity of CMP at arthroscopy. Results: There were 50 TTT’s followed up (7 staged bilaterals) with a mean follow up of 32.4 months (5–88 months). There were significant improvement in the pre-operative and post-operative Kujala (p> 0.001) and visual analogue pain scores (p> 0.001). Of the 50 TTT’s 70% had an excellent or good result and 30% a fair or poor result. Moreover 76% claimed that they would have the same operation again for their condition. There was no significant correlation between Outerbridge grading and post-operative outcome. Complications include late anterior knee pain (10 cases), superficial wound infection (1 case), non-union of osteotomy (1 case) and tuberosity fracture (1 case). Conclusion: Anteromedial tibial tubercle transfer is a reliable and effective treatment for peristant anterior knee pain

The purpose of this study was to test the hypothesis that patella alta leads to a less favourable situation in terms of patellofemoral contact force, contact area and contact pressure than the normal patellar position, and thereby gives rise to anterior knee pain. A dynamic knee simulator system based on the Oxford rig and allowing six degrees of freedom was adapted in order to simulate and record the dynamic loads during a knee squat from 30° to 120° flexion under physiological conditions. Five different configurations were studied, with variable predetermined patellar heights. The patellofemoral contact force increased with increasing knee flexion until contact occurred between the quadriceps tendon and the femoral trochlea, inducing load sharing. Patella alta caused a delay of this contact until deeper flexion. As a consequence, the maximal patellofemoral contact force and contact pressure increased significantly with increasing patellar height (p < 0.01). Patella alta was associated with the highest maximal patellofemoral contact force and contact pressure. When averaged across all flexion angles, a normal patellar position was associated with the lowest contact pressures. Our results indicate that there is a biomechanical reason for anterior knee pain in patients with patella alta

Introduction. Special high-flexion prosthetic designs show a small increase in postoperative flexion compared to standard designs and some papers show increased anterior knee pain with these prosthesis. However, no randomised controlled trails have been published which investigate difference in postoperative complaints of anterior knee pain. To assess difference in passive and active postoperative flexion and anterior knee pain we performed a randomized clinical trial including the two extremes of knee arthroplasty designs, being a high flex posterior stabilized rotating platform prosthesis versus a traditional cruciate retaining fixed bearing prosthesis. We hypothesised that the HF-PS design would allow more flexion, due to increased femoral rollback with less anterior knee pain than the CR design. We specifically assessed the following hypotheses:. Patients have increased flexion after HF-PS TKA compared to CR TKA, both passive and active. Patients show an increased femoral rollback in the HF-PS TKA as compared to the CR TKA. Patients receiving a HF-PS TKA design report reduced anterior knee pain relative to those receiving the CR TKA. Methods. In total 47 patients were randomly allocated to a standard cruciate retaining fixed bearing design (CR) in 23 patients and to a high-flexion posterior stabilized mobile bearing design (HF-PS) in 24 patients. Preoperative and one year postoperative we investigated active and passive maximal flexion. Furthermore, we used the VAS pain score at rest and during exercise and the Feller score to investigate anterior knee pain. A lateral roentgen photograph was used to measure femoral rollback during maximal flexion. Results. The HF-PS did show a significantly higher passive postoperative flexion; 120.8° (SD 10.3°) vs. 112.0° (SD 9.5°) for the CR group (p=0.004). The active postoperative flexion, VAS-pain score and Feller score did not show significant differences between both groups. Sub analysis with the HF-PS group showed a higher VAS-pain for the patients achieving ≥130° of flexion; 30.5 (SD 32.2) vs. 12.2 (SD 12.5) (p=0.16). The rollback was significantly lower in the CR group compared to the HF-PS group; 4.4 (SD 3.0) vs. 8.4 (SD 2.1). Conclusion. The present study showed a significant higher passive flexion in the Posterior Stabilised-High Flexion mobile bearing compared to a Cruciate Retaining fixed bearing prosthesis. However, this difference disappeared when comparing active flexion. The difference in passive flexion was probably related to a significantly lower rollback causing impingement in the CR prosthesis. No difference in anterior knee pain was found between both groups. However, a suggestion is raised that achieving high-flexion might lead to more patellofemoral complaints/anterior knee pain

Achieving deep flexion of knee after total knee arthroplasty (TKA) is particularly desirable in some Asian and Middle Eastern who have daily or religious customs typically use full knee flexion. After TKA, some patients complained about anterior knee pain during deep knee flexion. We evaluated the efficacy of arthroscopic fat pad resection in a series of patients suffering from anterior knee pain associated with high flexion achievement after TKA. The efficacy of fat pad resection via arthroscopy for treating anterior knee pain associated with high flexion angle (average = 133.1°) was evaluated in eight knees of eight patients among 207 knees performed between 1996 and 1999. The mean age of patients was 71.1 years when the primary TKA was performed. All implatants were posterior stabilized type (IB-II, Nexgen PS and LPS). The symptom of anterior knee pain during deep knee flexion developed within one year after TKA in all cases. In addition to pain in eight knees, two patients have crepitation as the knee was flexed and extended and three patients had hydrarthrosis. Impingement and fibrosis of fat pad were confirmed, and fibrous structures were removed by arthroscopy. Before arthroscopy, the symptom obviously subsided after injection of local anesthesia into infrapatellar fat pad. Patellar clunk syndrome is also soft tissue impingement and suprapatellar fibrous nodule becomes entrapped intercondylar notch on the femoral component during knee flexion. On this point, these cases does not cause by patellar clunk syndrome. After fat pad resection, the symptom disappeared, and keeps symptom-free after a mean follow-up of six years five months in all cases. Any complications following fat pad resection, such as patella baja and necrosis, were not experienced. Those cases achieving higher flexion angle tended to experience severe pain and shorter time interval between TKA and arthroscopic surgery, suggesting impingement of the infrapatellar fat pad is closely related to deep flexion after TKA. These results demonstrate that the anterior knee pain due to repetitive infrapatellar fat pad impingement is one of the complications during deep knee flexion after TKA, and the arthroscopic fat pad resection is useful to relief the anterior knee pain. Because of our experience with patients encountering anterior knee pain, we have begun to remove 70 to 80% of the fat pad during the primary TKA procedure since 1999, and until today, none developed anterior knee pain thought to be associated with fat pad impingement, patellar baja nor patellar necrosis. We suggest that fat pad resection is necessary to prevent the anterior knee pain due to fat pad impingement during deep flexion in TKA

The prevalence of anterior knee pain in the general population is relatively high. Patellar height, and more specific patella alta, is one of the several factors that have been associated with anterior knee pain, but the precise mechanism by which patella alta leads to a less favourable situation in terms of patellofemoral contact force, contact area and contact pressure, is poorly understood. The recent availability of validated dynamic knee simulators and advances in the analysis of contact force and area, give us today the possibility to study the influence of patellar position and patellar height on patellofemoral biomechanical characterisitics. Simulating a knee squat in different configurations with variable predetermined patellar height, reveals a clear association of patella alta with the highest maximal patellofemoral contact force and contact pressure, probably as a consequence of the delay in tendofemoral contact. When averaged across all flexion angles, the normal height of the patella seems to be the most optimal position in terms of contact pressures. This may provide a biomechanical explanation for anterior knee pain in young patients with patella alta and in older patients following total knee prosthesis resulting in an altered patellar position in terms of height

The aim of this study was to assess the outcome of patients who underwent ElmslieTrillat antero-medial tibial tubercle transfer for treatment of persistent symptomatic anterior knee pain due to chondromalacia patellae. We performed a prospective analysis of 23 patients who underwent Elmslie-Trillat antero-medial tibial tubercle transfers over a five year period for chronic anterior knee pain and an arthroscopic diagnosis of chondromalacia patellae. All patients who presented with anterior knee pain underwent an initial period of physiotherapy and all patients whose symptoms persisted following physiotherapy underwent arthroscopic assessment. Patients who continued to experience debilitating symptoms despite this initial treatment and who also had a diagnosis of chondromalacia patellae from arthroscopic assessment were listed for an Elmslie-Trillat tibial tubercle anteromedialisation. Patients who gave a history of instability or dislocation were excluded. The average age of patients undergoing surgery was 34 years (21–48 years) and the average time between arthroscopic diagnosis and surgery was 14 months. All patients who underwent surgery had pre and post operative KuJala patellofemoral scoring. The average pre-operative score was 54 (30–78) and post operative score 76 (46–100). The average post operative assessment was 25 months (6–62 months). Twenty one patients had improved post operative scores with one having a worse score and one score remaining unchanged following surgery. Nineteen patients felt that their symptoms had improved, three felt that there had been no change and one felt that they were worse after surgery. When asked if the improvement in symptoms had been worthwhile nineteen stated that they would undergo surgery again if in the same situation and four stated that they would not. The treatment of symptomatic chondromalacia patellae remains a challenge. Although a more selective approach to individuals with anterior knee pain is widely advocated in the literature this study demonstrates that good results can still be achieved in patients treated empirically with a tibial tubercle anteromedialisation

Total knee arthroplasty (TKA) disturbs patellar blood flow, an unintended accompaniment to TKA that may be a cause for postoperative anterior knee pain. We compared patellar blood flow before and after medial parapatellar arthrotomy to pre- and postoperative anterior knee pain scores to ascertain whether disrupted patellar blood flow correlates with anterior knee pain following TKA. Blood flow measurements were performed at full extension and at 30°, 60°, 90° and 110° of flexion prior to and after medial arthrotomy in 50 patients (21 male, 29 female; mean age 73.1±8.6 years) undergoing TKA. Anterior knee pain was assessed using the pain intensity numeric rating scale. A significant decrease in blood flow was detected at 60°, 90°, and 110° of flexion (p values: 0.00314,< 0.0001,< 0.0001 respectively). The medial arthrotomy did not have a statistically significant influence on patellar blood flow in the Students’ t-test (margin of significance p& #61603;0.05) Nineteen patients exhibited an average 14% (range 1%–54%) increase in patellar blood perfusion at knee flexions of 90° and 110° after medial arthrotomy (p value: 0.32) Prior to TKA, 16 of the 50 patients (32%) complained of anterior knee pain (average NRS 7.12, range 5–10). At 6-month follow up, 4 of the 16 patients (25%) complained of moderate anterior pain (average NRS 5.7, range 5–6), while 8 of 16 (50%) patients reported discomfort (average NRS 3.5, range 2–4) around the patella. No statistically significant correlation was found between intraoperative findings on patellar blood flow and the presence of anterior knee pain

Whereas thermography has already been used as an assessment of disease activity in some kinds of inflammatory arthritis, it is a new method for objektive pain evaluation in patients with joint prosthesis. To our knowledge, no study has tested the correlation between increase of temperature and anterior knee pain with total knee prosthesis yet. Thirteen patients were included in this study who suffered from anterior knee pain of the retinaculum patellae with total knee prosthesis. The patients were asked to walk 3 km before entering a room which was cooled down to 20 degrees Celsius. A black 1 cm times 4.5 cm square stripe was attached on the diameter of the patella and the patients rested for 20 minutes to cool down before thermographic fotos were taken from 90 degrees, 45 degrees, frontal medial and lateral. The evaluation of temperature difference of each side was performed by marking a 1cm times 2cm square field rectangular around the black stripe and comparing it with a reference point of the same size 3 cm distal of the field. The patients were compared with thirteen others, not suffering from anterior knee pain. Statistical analysis was performed using a t- test and a p value < 0.05 was considered to be significant. The temperature differences between the rectangular field and the reference point increased significantly on the medial (p= 0.00037) or lateral (p= 0.000002) pain side of the knee. The thirteen knees with knee pain had significantly higher temperature differences between medial and lateral temperature differences, than the knees without knee pain. We demonstrate a significant correlation between anterior knee pain and an increase of superficial skin temperature around the retinaculum patellae. To our knowledge, this is the first report of an objective assessment of pain of the retinaculum patellae with total knee prosthesis

Anterior knee pain in adolescents is generally recognised as a common but benign self-limiting condition. Although many operative procedures for its treatment have been proposed, there is little statistical evidence that they are more effective than expectant management. A group of 54 adolescent girls has been followed for two to eight years from presentation with anterior knee pain. Although some pain persisted in the majority, in many the symptoms declined in severity. This study provides a baseline for comparison with the results of operative intervention; it is suggested that surgical treatment is unproven and unnecessary

Introduction. Anterior knee pain is a common presentation of patello-femoral dysfunction and patients with this disorder represent a significant proportion attending a specialist knee clinic. There is an on-going debate as to the cause and best treatment for such patients. Previous studies on patella-femoral morphology have suggested patella maltracking plays an important part in the aetiology but there had been no studies correlating maltracking with articular cartilage change. Methods. We studied 147 consecutive patients (294 knees) aged between 10 and 63 presenting with anterior knee pain. All underwent MRI tracking scan of their knees as part of the routine investigations. We analysed the prevalence of maltracking with respect to gender, laterality and age groups, as well as patello-femoral articular cartilage changes. Results. 52% of patients were found to have maltracking, of which 75% were bilateral. Furthermore, 66% of patients with maltracking had radiological evidence of patellar articular cartilage changes, corresponding to 61% of 294 knees examined. While majority of these occur at lateral facet, a proportion of medial facet changes (16%) is also seen. More significantly, while 25% of knees from patients with maltracking under the age of 20 are found to have changes on the patella cartilage, this increases to 93% by the age of 50 or above, with step-wise increment per decade of age (p<0.01). Conclusion. Our results demonstrate a strong correlation between anterior knee pain symptoms, patella maltracking and changes in patello-femoral joint cartilages of varying severity. This has implications on the management of these patients and would suggest early correction of maltracking is indicated to prevent deterioration in the patello-femoral joint

We performed an advancement and medial transfer of the tibial tuberosity based on Fulkerson's principle to treat intractable anterior knee pain associated with patellofemoral maltracking diagnosed by dynamic MRI. Between January 1998 and July 2000 twenty-two patients had 28 knees operated for anterior knee pain. There were 4 men and 18 women with a mean age of 28 years (range 18-41). Indications for surgery were [a] failure to improve after six months of physiotherapy and [b] patellofemoral maltracking evident in dynamic MRI. Mean follow-up was for 37 months (23 – 42). Knee instability score modified by Fulkerson was employed for objective and subjective assessment. Objectively 22 (79%) knees achieved good to excellent results. Four knees (14%) had fair, and two (7%) had poor results. Excellent and very good results were seen in 20 knees. These patients were a younger age group (mean age 21 years) and had minimal degeneration (grade I-II) of the patellofemoral joints. Two patients achieved good results. One of them had moderate (grade III) and one minimal (II) arthritis. Three knees with fair results had advanced (grade IV or V) and one had moderate (grade III) arthritis. Out of two patients who had a poor result, one had advanced degeneration (grade V) that later required a patellofemoral joint resurfacing. The other was a 24 year old woman with grade II changes. She was treated by the pain therapy team. Anterior displacement of the tuberosity in the presented study was kept to 5 mm to avoid the possible complications of wound break down. The overall length and depth of the osteotomy was also reduced to minimise risk of fracture and commence early mobilisation. Based on our results there is a strong case of justification for Anteromedialisation of tibial tuberosity using a smaller length of osteotomy and lesser degree of anteriorisation in carefully selected patients with Patellofemoral arthralgia associated with maltracking patella

We assessed patellofemoral joint function by combining the measurement of maximal isometric extensor torque at the knee with clinical and radiological measurements in order to calculate the patellofemoral contact force. Eighteen volunteers established the normal ranges of results and the reliability of the system. Of the 39 patients with a variety of knee problems, 29 had anterior knee pain, and all had a subsequent arthroscopy. Patients with anterior knee pain and lesions in the patellar cartilage had significantly reduced isometric contact forces, but those with normal patellofemoral cartilage had normal contact forces. Our method may be useful in providing an objective assessment of anterior knee pain and a quantitative means of monitoring its treatment

Introduction: Poor proprioception and imbalance between quadriceps and hamstrings have been suggested as causes for anterior knee pain. The aim of our study was to compare the proprioception of patients with anterior knee pain to a normal population and to compare the activity of quadriceps and hamstrings using electromyography (EMG) in the 2 groups. Methods: Patients and controls between the ages 11–25 yrs were recruited into the study. The proprioception (stability index) of the patients and controls was tested using the Biodex stability system. This computerised system tests the ability of a person to balance his/her own body on a platform that moves in various directions. Surface EMG was recorded from the quadriceps and hamstrings during this test. EMG was also recorded as the patients and controls stepped onto a 20cm step. EMG activity was normalised to levels elicited during maximal isometric contractions. Results: 18 patients and 27 controls were recruited. We found no significant difference between the groups in the EMG intensity of vastus lateralis relative to biceps femoris, or vastus medialis relative to vastus lateralis, during the balance test or during the step up task (Mann Whitney U test all p> 0.05). We did not find any difference in the proprioceptive abilities of the two groups. Conclusion: We found no significant difference between the groups in the intensity of muscle contraction of the hamstrings relative to the quadriceps, i.e. no evidence for an imbalance in the patients. However the temporal relation between the two needs further investigation

Purpose: The study was designed to evaluate the biomechanical and neurohistological properties of the infrapatellar fat especially concerning its potential role in the anterior knee pain syndrome. Methods: Isokinetic knee extension from 120 of flexion to full extension was simulated on 10 human knee cadaver specimens (6 male, 4 female, average age at death 44 years). Joint kinematics was evaluated by ultrasound sensors (CMS 100TM, Zebris, Isny, Germany), and retro-patellar contact pressure was measured using a thin-film resistive ink pressure system (K-ScanTM 4000, Tekscan, Boston). The infrapatellar tissue pressure was analyzed using a closed sensor cell. The patellar contact pressure was measured before and after resection of the infrapatellar fat pad. The distribution of nerve fibres in the infrapatellar fat pad was assed immunohistologically in a second part of the study. Results: Infrapatellar tissue pressure significantly increased during knee extension < 20 and flexion > 100 ranging from 343 (223) mbar at O- to 60 (64) mbar at 60 of flexion. Total resection of the infrapatellar fat pad resulted in a significant decrease in tibial external rotation of 3° in full knee extension (p=0.011), combined with a significant medial translation of the patella between 29 and 69° knee flexion (p=0.017 to 0.028). Retropatellar contact pressure was significantly (p< 0.05) reduced at all flexion angles, at 120° knee flexion more than in full knee extension. Studying all the detectable nerves present in 50 fields (x200 objective) we found an average of 6.4 substance-P- (25%) of a total of 24.7 nerve fibres in the infrapatellar fat pad. There was a significantly (p< 0.01) higher number of substance-P-fibers (24.4 (28%) of 105.7) in the superficial synovial tissue. The number of S-100-fibers was significantly (p< 0.05) higher in the central and lateral part of the fat pad. Conclusions: Based on these results, we conclude that resection of the infrapatellar fat pad could potentially reduce clinical symptoms in the anterior knee pain syndrome, and that, contrary to commonly believed, the infrapatellar fat pad may have a biomechanical function and play a role in the anterior knee pain syndrome

Postoperative anterior knee pain was evaluated in a consecutive series of 138 knees in 108 patients with rheumatoid arthritis treated by total knee replacement with Mark I Insall-Burstein prostheses. No knee had primary patellar resurfacing, and in the 119 knees followed up for a mean of 63.9 months, none had secondary resurfacing. Anterior knee pain was absent in 87 knees (73%), mild in 16 (13.5%) and moderate or severe in 16 (13.5%). The height of the patella above the prosthetic joint line was the only variable which was directly related to the incidence of anterior knee pain. The sensitivity and specificity of patellar height measurements for identifying patients with or without pain were derived. From these data, a selective policy of resurfacing the patella in those at risk was adopted. Choosing a patellar height of 15 mm or less, patellar resurfacing could be avoided in 80% of patients likely to have no pain, and the patella could be resurfaced in 65% of those likely to have anterior knee pain

Introduction. A comprehensive met-analysis of anterior knee pain post intramedullary nailing of the tibia was performed by Katsoulis et al in 2006. The principle findings were that 47.4% of patients had anterior knee pain at 2 years post tibial nailing. Worse results were found following a patella tendon splitting approach when compared with a medial para-patellar tendon approach. These conclusions were drawn from 20 studies including 1460 patients. Currently both approaches to the proximal tibia for nailing are used at JCMH Blanchardstown. A retrospective study was performed to compare the results of tendon splitting and tendon sparing approaches to tibial nails and to compare the results of JCMH with those stated in literature. Method. Patients who underwent tibial nailing in 2007 and 2008 were identified using the hospital coding system. Those patients who were treated under the care of Mr Kenny had a medial para-tendinous approach and those treated the care of Mr O'Flanagan and Mr Keogh had a tendon splitting approach. Apart from the approach the nailing technique using the Trigen Knee Nail and the post operative physiotherapy protocol were identical. Follow up included questions regarding knee pain and return to previous function. Specifically: Knee pain that affects daily life, Knee pain on kneeling, Knee pain on ascending or descending stairs, Return to work and Return to sports or active hobbies. Results. 61 patients were treated with intra-medullary nailing between 2007 and 2008 43 were available for follow for the purposes of this study (70 %). 25 had nails inserted via a tendon splitting approach and 18 via a tendon sparing approach. Only 5% of patients had knee pain that affected daily life, 16 % had pain on kneeling, 90% of patients who were previously at work returned to work and 75% of patients who were previously engaged in sports were able to return to these activities. Discussion. These results are significantly better than the figures stated in literature in terms of knee pain, return to work and sports. There was no significant difference between the 2 approaches to the tibia again in contradiction of available literature

To assess the prevalence of anterior knee pain more than 5 years after closed intramedullary nailing of the tibia and evaluate the long-term socioeconomic impact of this complication in terms of knee function and employment. A retrospective, cohort study of 298 consecutive tibial intramedullary nailings in 295 patients. Minimum follow-up was 5 years and patients were assessed using a questionnaire and the Lysholm knee score. 26 patients are known to have died, 22 patients, greater than 60 years at the tune of their injury, were excluded, Thus, 251 knees in 248 patients were available for review. The mean age at follow-up was 40. 8 years. The male to female ratio was SA:1 and mean follow-up was 7. 9 years. Anterior knee sensory disturbance was reported by 58% of patients. This interfered with activities of daily living (ADLs) in 29%, work in 25% and sport in 37%. Anterior knee pain was reported by 47% of patients. This interfered with ADLs in 37%, work in 36% and sport in 57%, Anterior knee pain was present all the time in 4%, often in 12%, sometimes in 27%, rarely in 21% and never in 37%, Pain on kneeling was rated on a visual analogue scale as mild in 54%, moderate in 34% and severe 12%. AKP improved with time in 73% patients and became worse in 4%. The Lysholm score rated 4 1 % knees as excellent, 19% as good, 26% as fair and 14% as poor. 86% of patients have been able to return to work, 9% are currently unemployed and 5% disabled. The presence of anterior knee pain was felt by the patient to prevent return to previous work in 10%. Anterior knee pain persists in 47% of patients after intramedullary nailing of the tibia- There is some decrease in symptoms with time and the majority of patients are able to return to work and activities of daily living. However, anterior knee pain causes significant disability in a small number and all patients should be warned of this problem prior to surgery

PURPOSES. Previous studies on patella-femoral morphology have suggested patella maltracking plays an important part in the aetiology but there had been no studies correlating maltracking with articular cartilage change. METHODS. We studied 147 consecutive patients (294 knees) aged between 10 and 63 presenting with anterior knee pain. All underwent MRI tracking scan of their knees as part of the routine investigations. We analysed the prevalence of maltracking with respect to gender, laterality and age groups, as well as patello-femoral articular cartilage changes. RESULTS. 52% of patients were found to have maltracking, of which 75% were bilateral. Furthermore, 66% of patients with maltracking had radiological evidence of patellar articular cartilage changes, corresponding to 61% of 294 knees examined. While majority of these occur at lateral facet, a proportion of medial facet changes (16%) is also seen. More significantly, while 25% of knees from patients with maltracking under the age of 20 are found to have changes on the patella cartilage, this increases to 93% by the age of 50 or above, with step-wise increment per decade of age (p<0.01). CONCLUSION. Our results demonstrate a strong correlation between anterior knee pain symptoms, patella maltracking and changes in patello-femoral joint cartilages of varying severity. This has implications on the management of these patients and would suggest early correction of maltracking is indicated to prevent deterioration in the patello-femoral joint

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging. Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique. On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking. Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release

Purpose of the study: To develop a new treatment algorithm for patients with chronic anterior knee pain based on kinematic patella tracking MR imaging. Methods and Results: Patients with anterior knee pain of more than one year duration and not responding to non-operative treatment, underwent kinematic MRI study. The provocative test was performed with the conventional MRI scanner and the patient extending the knee against resistance, the resistance provided by inflated beach ball. A retrospective analysis was done of first seventy patients, who had undergone this scanning technique. On the imaging films, four measurements were made. They were patella subluxation, tilt, cartilage thickness and the Tibial Tubercle Trochlear distance (TTD). Patellar subluxation was classified as mild, moderate and severe. We found that a Tibial Tubercle Trochlea distance of 18mm had a specifity of 100% and a sensitivity of 89% for severe maltracking. Conclusion: Kinematic MR Imaging is a useful investigation before considering operative treatment for patients with chronic anterior knee pain. Based on our study, we conclude that those patients with moderate lateral maltracking with a TTD< 18 mm should be offered lateral release and those with severe maltracking and TTD> 18mm should have a tibial tubercle transfer, in addition to lateral release

Out of a total of 623 patients who, over a ten-year period, underwent primary total knee replacement (TKR) without patellar resurfacing, 20 underwent secondary resurfacing for chronic anterior knee pain. They were evaluated pre- and postoperatively using the clinical and radiological American Knee Society score. The mean follow-up was 36.1 months (12 to 104). The mean knee score improved from 46.7 to 62.2 points and the mean functional score from 44.7 to 52.2 points. Only 44.4% of the patients, however, reported some improvement; the remainder reported no change or deterioration. The radiographic alignment of the TKR did not influence the outcome of secondary resurfacing of the patella. Complications were noted in six of the 20 patients including fracture and instability of the patella and loss of movement. Anterior knee pain after TKR remains difficult to manage. Secondary resurfacing of the patella is not advocated in all patients since it may increase patient dissatisfaction and hasten revision

Anterior knee pain after total knee arthroplasty (TKA) occurs in 5% to 30% of patients whether or not the patella has been resurfaced. We retrospectively reviewed our patients, none of whom underwent patellar resurfacing. Only 2% had anterior knee pain, none requiring revision surgery. Our follow-up was between two and five years. We paid particular attention to removing osteophytes and conducting a thorough peripatellar synovectomy and a circumpatellar cautery denervation. Our results compare favourably to those in the literature, whether or not the patellae were resurfaced. We conclude that patellar resurfacing in TKA is unnecessary when careful attention is paid to the peripatellar tissues

Introduction and Aims: Many authors believe that patellar resurfacing decreases the incidence of anterior knee pain. We analysed the result of 150 of our own patients. Method: Over the past four years we performed 150 total knee arthroplasties. None of the patellae were resurfaced, osteophytes were carefully removed, the patellae debrided, a thorough peri-patellar synovectomy and circumpatellar cautery denervation performed. All patients were examined by a consultant and a registrar to determine the site of any pain complaint. If there was any controversy a third surgeon was consulted. Results: No patient had pain severe enough to warrant revision surgery. Only two patients had anterior knee pain, and in neither was it marked. Conclusion: We do not know whether our favourable results are attributable to the patellar management, or due to the prosthesis used. We concede that a prospective randomised trial is necessary to determine this, but with such a low incidence of patellar complications we feel this is not ethically justified

The purpose of this study was to evaluate the influence of trochlear design in total knee replacement with and without patellar resurfacing. Methods and Results: In 1992 a trial was set up, including all patients undergoing primary PFC (Johnson & Johnson) total knee replacement. Patients were randomised to either patellar resurfacing or retention. The patients were assessed using the American Knee Society rating, a clinical anterior knee pain score and BOA patient satisfaction score. Assessment was performed without knowing whether the patella had been resurfaced. In July 1998 we began using the PFC Sigma. This incorporates a deeper trochlear groove with a 5° valgus angle. We compared the results for the two types of prosthesis. In the PFC group there were 474 knees in 390 patients. Follow-up was from 2 to 9 years (mean 5.5 years). The overall prevalence of anterior knee pain) was 25.1% (58 knees) and 5.3% (13 knees) in the non-resurfaced group (n=231) versus the resurfaced group (n=243) respectively. Anterior knee pain became apparent in all cases within 18 months. In the PFC sigma group there were 67 knees in 62 patients. Follow-up was from 18 months to 3 years (mean 2 years). The incidence of anterior knee pain was 0 in the resurfaced group (n=30) versus 37.8% (14 knees) in the non-resurfaced group (n=37). Knee scores were lower in the non-resurfaced groups for each prosthesis. Conclusion: The prevalence of anterior knee pain was significantly higher in knees with non-resurfacing of the patella. The asymmetrical, deeper femoral groove improves anterior knee pain with the resurfaced patella but may contribute to it if not resurfaced. We recommend patellar resurfacing in all cases where technically possible

Aims: To report the outcome of secondary patellar resurfacing in patients with chronic anterior knee pain following primary total knee replacement. Methods: A total of twenty patients identified over a 10-year period from 623 patients managed without patellar replacement during primary knee arthroplasty were included and evaluated pre and postoperatively using the American Knee Society (AKS) score, as well as by radiological analysis. Results: The mean follow up was 36.1 months (range 12–104 months). The mean knee score improved from 46.7 to 62.2 points while the mean functional score increased from 44.7 to 52.2 points. Only 44.5% of the patients reported some improvement whereas the remaining reported no change or deterioration. Postoperative radiographic alignment of the primary knee arthroplasty did not influence outcome of secondary patellar resurfacing. Complications were noted in 6 of the 20 patients including patella fracture, patella instability and loss of a range of movement. Conclusions: Anterior knee pain following knee arthroplasty remains a difficult condition to manage and secondary resurfacing of the patella is clearly not to be advocated in all patients since it may well increase patient dissatisfaction and hasten revision

Many authors believe that patellar resurfacing decreases the incidence of anterior knee pain. We analysed the results of 98 of our own patients (103 knees). Over the past two years, we performed total knee arthroplasty on 23 men (one bilateral) and 75 women (four bilateral). None of the patellae were replaced, but we carefully removed osteophytes, debrided the patella, and performed a thorough peripatellar synovectomy and circumpatellar cautery denervation. All patients on our database were telephoned, and those who reported pain were examined independently by a consultant and a registrar. If there was any controversy about the site of the pain, a third surgeon saw the patient. No patient had pain severe enough to warrant revision surgery. Only two (2%) had anterior knee pain, and in neither of them was it marked. We do not know whether our favourable results are attributable to the peripatellar synovectomy and/or circumpatellar cautery denervation. While we concede that a control study of patients who have undergone patellar resurfacing might be necessary before a firm conclusion can be drawn, we question whether, with such a low incidence of patellar problems, this is ethically justifiable

Idiopathic anterior knee pain (AKP) is common in adolescents and young adults. Most believe that the origin of the problem lies in the patello-femoral joint. Hamstring tightness has also been attributed as an important cause. The aim of our study was to compare biometric parameters in patients with idiopathic AKP and controls. We also wanted to assess whether there was a difference in the relative electromyographic (EMG) onset times of the medial and lateral hamstrings. We prospectively recruited patients with idiopathic anterior knee pain in the age group 11 to 25. Patients, but not the control population, had AP, lateral and skyline radiographs taken to rule out other pathology. We had 34 patients (60 knees) with a minimum one year follow up. There was no difference in the symptoms of patients who attended physiotherapy as compared to those who did not. Patients with knee pain had significantly more hip external rotation (63 deg) as compared to the control (47 deg) group (p=0.001). Patients also had significantly more hamstring tightness (p=0.04). Surface EMG was recorded (17 patients and controls each) from the medial and lateral hamstrings during 3 repetitions of a maximal voluntary isometric contraction exercise with the knee at 45° of flexion. The lateral hamstrings contracted 48.7 m.sec earlier than the medial hamstrings in patients as compared to controls. AKP is a multifactorial and self-limiting disorder. Earlier contraction of the lateral hamstrings may cause tibial external rotation and contribute to the symptoms. Our data suggests that physiotherapy did not significantly alter the course of the condition. We believe that increased hip external rotation may contribute to the symptoms by increasing medial facet stress

Anterior knee pain (AKP) is the commonest complication of total knee arthroplasty (TKA). This study aims to assess whether sagittal femoral component position is an independent predictor of AKP after cruciate retaining single radius TKA without primary patellofemoral resurfacing. From a prospective cohort of 297 consecutive TKAs, 73 (25%) patients reported AKP and 89 (30%) reported no pain at 10 years. Patients were assessed pre-operatively and at 1, 5 and 10 years using the short form 12 and Oxford Knee Score (OKS). Variables assessed included demographic data, indication, reoperation, patella resurfacing, and radiographic criteria. Patients with AKP (mean age 67.0 (38–82), 48 (66%) female) had mean Visual Analogue Scale (VAS) Pain scores of 34.3 (range 5–100). VAS scores were 0 in patients with no pain (mean age 66.5 (41–82), 60 (67%) female). Femoral component flexion (FCF), anterior femoral offset ratio, and medial proximal tibial angle all differed significantly between patients with AKP and no pain (p<0.001), p=0.007, p=0.009, respectively). All PROMs were worse in the AKP group at 10 years (p<0.05). OKSs were worse from 1 year (p<0.05). Multivariate analysis confirmed FCF and Insall ratio <0.8 as independent predictors of AKP (R. 2. = 0.263). Extension of ≥0.5° predicted AKP with 87% sensitivity. AKP affects 25% of patients following single radius cruciate retaining TKA, resulting in inferior patient-reported outcome measures at 10 years. Sagittal plane positioning and alignment of the femoral component are important determinants of long-term AKP with femoral component extension being a major risk factor

Introduction. Anterior knee pain (AKP) is a recognized cause of patient's dissatisfaction after total knee arthroplasty. Potential implant/technique related contributors to AKP are patellofemoral maltracking, trochlear geometry, femoral malrotation, patellar tilt and overstuffing. The primary aim of this prospective, matched pair study was to assess the safety, efficacy and performance of an anatomic patella and its effect on AKP in in a matched pair analysis. Material and Methods. Between July 2012 and May 2013, 55 consecutive posterior stabilized cemented Attune TKAs (Depuy) were matched to the PFC Sigma group based on age, gender, and body mass index (BMI). All surgeries were performed via medial parapatellar approach with patellar resurfacing. Clinical and radiographic analysis was performed prospectively with minimum 6 month follow-up. Radiographic measurements included overall limb alignment, anterior offset, posterior offset, joint line, patellar thickness, patellar tilt and patellar displacement by two independent observers. Results. The mean functional outcomes were similar in both groups. AKP incidence between Attune and PFC was statistically insignificant (3.6% and 3.8%). Radiographic analysis revealed no mal-alignment, or osteolysis. No complications such as infection, patellar fracture, subluxation or dislocations were observed. Discussion. Attune knee design demonstrates excellent short-term safety and efficacy. At minimum 6-month follow-up, anatomical patella with shows less AKP than single radius patella design. Longer follow-up is required to assess functional outcome this design

The aim was to compare anterior knee pain (AKP) felt before, and after hamstrings (HS, n = 65) and bone-patellar tendon- bone [B-PT-B, n = 94] ACL reconstructions. The same questionnaire (modified from Shelbourne et al 1997) was answered by patients before, and at least 12 months after surgery. Questions covered five main categories of pain ie. during prolonged sitting, stair climbing, kneeling, sport or vigorous activity, and ADL. There was no statistical difference in the two groups in overall AKP scores before surgery. After surgery, there were improvements in this overall score in both groups, but the improvement was statistically greater in the HS group (p = 0.02). Analysis of the five different pain categories showed no significant difference in the improvements in sitting, sport or ADL. In both climbing stairs (p = 0.009), and kneeling (p = 0.02) there were significantly greater improvements in the HS group. The majority of patients had AKP before surgery. Surgery improved pain levels in both HS and B-PT-B groups, but there was statistically significant greater improvements in overall AKP scores, and the scores for climbing stairs and kneeling in the HS group

We report a rare case of an intracortical chondroma in the region of the medial femoral condyle of the femur extending into the femoral sulcus and the patellofemoral joint.A sixteen year old Asian boy presented with repeated episodes of right sided anterior knee pain and giving way over a three year period. The patient had been treated previously for multiple bony swellings at another hospital and a diagnosis of multiple enchondromatosis had been made. Examination revealed that the patellofemoral compression test was positive with fullness over the medial eminence of the femur in the region of the trochlear groove.Pre-operative X-rays and MRI scan showed the presence of an intracortical lesion over the medial femoral condyle extending into the femoral sulcus. The lesion demonstrated intermediate signal intensity on T1 and high intensity on T2 weighted images with variable low signal intensity foci due to the presence of a calcified matrix. The patient underwent arthroscopic examination. An intra-articular lesion (2cmx 3cm.) was identified and excised through a mini-arthrotomy. The lesion was entirely intra-articular arising from the medial femoral condyle proximal to the femoral sulcus, extending partially into the supra-patellar pouch. Histopathological examination confirmed the presence of a low grade cartilaginous neoplasm best diagnosed as an atypical chondroma. At a two year follow up appointment the patient was found to be asymptomatic with no evidence of radiological recurrence. Although there have been several reports of periosteal chondromas developing around the knee the majority deal with soft tissue chondromas in para-articular locations or intra-cortical tumours in extra-articular regions. Our tumour is unique due to its intra-articular and intracortical location. A detailed review of the literature of this rare tumour is presented with a pictorial presentation of the case including arthroscopic radiological and histopathological findings

Purpose. Anterior knee pain has been relieved by resection of the infrapatellar plica (IPP). The question is: How? The hypothesis is: the IPP acts as an intra-articular ligament, a mechanical link between the forces of knee motion, the fat pad (FP) and the distal femur, holding the FP captive through the arc of motion. Release of the IPP severs this link, allowing the highly innervated FP to move freely. This may allow any underlying pathologic process to heal. Method. Anatomic dissection: In 12 knees, the extensor apparatus was released from the femur and retracted distally allowing relationships to be examined. Cadaver studies: Lateral fluoroscopy was used as well as direct arthroscopic visualization to control implantation of tantalum beads or radiographic contrast material in the FP and IPP. The knee was taken through the arc of motion repeatedly. The femoral attachment of the IPP was then released and knee motion repeated. Traction on the extensor apparatus simulated active motion. In-Vivo Study: The IRB approved study of 12 volunteers undergoing planned knee arthroscopy under local anesthesia. Contrast was placed in the FP and IPP under lateral fluoroscopic control. Passive, then active motion then a quads-set manoeuvre was performed. The IPP was resected and knee motion again recorded. Results. Knees without IPP (4) demonstrated FPs that were lobular, with lateral bodies, and a central process. The fibrous synovial layer of the capsule bypassed the FP inserting on the superior aspect of the menisci. Knees with an IPP (8) showed a FP that was covered by fibrous synovium. The fibrous elements of the capsule coalesced on either side of the patellar in folds that merged with the alar folds. These fibrous elements ramified over and through the FP and were continuous with the upper portion of the IPP medially and laterally. Inferiorly the lower portion of the IPP merged with fibrous synovium that attached to the superior aspect of the menisci and the inter-meniscal ligament. The cadaver studies demonstrated that the IPP elongated with FP distortion as the knee approached full extension and flexion, and that the IPP was lax through mid arc. Release of the IPP at the femur eliminated almost all of the distortion through the full arc. The In-Vivo study replicated the cadaver observations for passive and active motion. The quads set manoeuvre caused further distortion of the FP with the patella moving one cm proximally. Release of the IPP eliminated FP distortion. Conclusion. The IPP seems to act as a true ligamentum mucosum. By virtue of its central femoral attachment if captures the FP against the end of the femur, loosely in mid arc, but with distortion of the FP and stretch of the IPP approaching full flexion and extension. This has been demonstrated in both cadavers and in in-vivo for the first time. Any pathologic process affecting the highly innervated FP will likely be improved by removal of the capture effect of the IPP

Aims: The purpose of the study was to determine the distribution and speciþcation of nerve þbers in the infrapatellar fat pad especially concerning nociceptive substance-P þbres. Methods: The infrapatellar fat pad was taken as a fresh specimen out of 21 patients (4 male, 17 female, mean age 69 years) during total knee arthroplasty. It was dissected in þve deþned parts, þxed and embedded in parafþn. Immunohistochemical techniques using antibodies against S-100 protein and substance-P were employed to determine and specify the nerve þbres. Results: Studying all the detectable nerves present in 50 þelds (x200 objective) we found an average of 6,4 substance-P- (25%) of a total of 24,7 nerve þbres in the infrapatellar fat pad. There was a significantly (p< 0,01) higher number of substance-P-þbers (24,4 (28%) of 105,7) in the surfacing synovial tissue. The number of S-100-þbers was signiþcantly (p< 0,05) higher in the central and lateral part of the fat pad. Conclusions: The occurance and distribution of nerve þbres in the infrapatellar fat pad suggests a nociceptive function. A neurohistological role in the anterior knee pain syndrome is assumed

The incidence of anterior knee pain following total knee replacement (TKR) is reported to be as high as 49%. The source of the pain is poorly understood but the soft tissues around the patella have been implicated. In theory circumferential electrocautery denervates the patella thereby reducing efferent pain signals. However, there is mixed evidence that this practice translates into improved outcomes. We aimed to investigate the clinical effect of intra-operative circumpatellar electrocautery in patients undergoing TKR using the LCS mobile bearing or Kinemax fixed bearing TKR. A total of 200 patients were randomised to receive either circumpatellar electrocautery (diathermy) or not (control). Patients were assessed by visual analogue scale (VAS) for anterior knee pain and Oxford knee score (OKS) pre-operatively and three months, six months and one year post-operatively. Patients and assessors were blinded. There were 91 patients in the diathermy group and 94 in the control. The mean VAS improvement at one year was 3.9 in both groups (control; -10 to 6, diathermy;. -9 to 8, p < 0.001 in both cases, paired, two-tailed t-test). There was no significant difference in VAS between the groups at any other time. The mean OKS improvement was 17.7 points (0 to 34) in the intervention group and 16.6 (0 to 42) points in the control (p = 0.36). There was no significant difference between the two groups in OKS at any other time. We found no relevant effect of patellar electrocautery on either VAS anterior knee pain or OKS for patients undergoing LCS and Kinemax TKR

Tibial and femoral deformities might cause patellofemoral problems, but they do not have to be modified every time to obtain good results. We have evaluated external tibial rotation characterised by an external tibial deformity in varus, worsening in parallel feet position. In these patients the only surgical treatment is tibial osteotomy, justified by a positive effect on the knee joint mechanics. From 1990 to 2002 we performed 25 derotation tibial osteotomies as an isolated procedure or associated with a closed wedge osteotomy. We reviewed 15 patients (16–28 years old at surgery) with special reference to pain, aesthetic criteria and functional assessments, and we reported possible negative effects of derotation (recurvation and external tibial rotation). In all the patients we found an external rotation higher than standard range and moderate varus. All patients had remission of pain; this was complete in five and partial in six. Ten patients showed an increased tibial rotation and eight of those showed even recurvation without functional sequelae. At 2–12 years of follow-up, our results are satisfactory.

In the absence of patellar resurfacing, we have previously shown that the use of electrocautery around the margin of the patella improved the one-year clinical outcome of total knee replacement (TKR). In this prospective randomised study we compared the mean 3.7 year (1.1 to 4.2) clinical outcomes of 300 TKRs performed with and without electrocautery of the patellar rim: this is an update of a previous report. The overall prevalence of anterior knee pain was 32% (95% confidence intervals [CI] 26 to 39), and 26% (95% CI 18 to 35) in the intervention group compared with 38% (95% CI 29 to 48) in the control group (chi-squared test; p = 0.06). The overall prevalence of anterior knee pain remained unchanged between the one-year and 3.7 year follow-up (chi-squared test; p = 0.12). The mean total Western Ontario McMasters Universities Osteoarthritis Indices and the American Knee Society knee and function scores at 3.7 years’ follow-up were similar in the intervention and control groups (repeated measures analysis of variance p = 0.43, p = 0.09 and p = 0.59, respectively). There were no complications. A total of ten patients (intervention group three, control group seven) required secondary patellar resurfacing after the first year. Our study suggests that the improved clinical outcome with electrocautery denervation compared with no electrocautery is not maintained at a mean of 3.7 years’ follow-up. Cite this article: Bone Joint J 2014;96-B:473–8

Objectives

Our study aimed to examine if a mobile-bearing total knee replacement (TKR) offered an advantage over fixed-bearing designs with respect to rates of secondary resurfacing of the patella in knees in which it was initially left unresurfaced.

Aims. This systematic review and meta-analysis aimed to compare the influence of patellar resurfacing following cruciate-retaining (CR) and posterior-stabilized (PS) total knee arthroplasty (TKA) on the incidence of anterior knee pain, knee-specific patient-reported outcome measures, complication rates, and reoperation rates. Methods. A systematic review of MEDLINE, PubMed, and Google Scholar was performed to identify randomized controlled trials (RCTs) according to search criteria. Search terms used included: arthroplasty, replacement, knee (Mesh), TKA, prosthesis, patella, patellar resurfacing, and patellar retaining. RCTs that compared patellar resurfacing versus unresurfaced in primary TKA were included for further analysis. Studies were evaluated using the Scottish Intercollegiate Guidelines Network assessment tool for quality and minimization of bias. Data were synthesized and meta-analysis performed. Results. There were 4,135 TKAs (2,068 resurfaced and 2,027 unresurfaced) identified in 35 separate cohorts from 33 peer-reviewed studies. Anterior knee pain rates were significantly higher in unresurfaced knees overall (odds ratio (OR) 1.84; 95% confidence interval (CI) 1.20 to 2.83; p = 0.006) but more specifically associated with CR implants (OR 1.95; 95% CI 1.0 to 3.52; p = 0.030). There was a significantly better Knee Society function score (mean difference (MD) -1.98; 95% CI -1.1 to -2.84; p < 0.001) and Oxford Knee Score (MD -2.24; 95% CI -0.07 to -4.41; p = 0.040) for PS implants when patellar resurfacing was performed, but these differences did not exceed the minimal clinically important difference for these scores. There were no significant differences in complication rates or infection rates according to implant design. There was an overall significantly higher reoperation rate for unresurfaced TKA (OR 1.46 (95% CI 1.04 to 2.06); p = 0.030) but there was no difference between PS or CR TKA. Conclusion. Patellar resurfacing, when performed with CR implants, resulted in lower rates of anterior knee pain and, when used with a PS implant, yielded better knee-specific functional outcomes. Patellar resurfacing was associated with a lower risk of reoperation overall, but implant type did not influence this. Cite this article: Bone Joint J 2023;105-B(6):622–634

The August 2023 Knee Roundup. 360. looks at: Curettage and cementation of giant cell tumour of bone: is arthritis a given?; Anterior knee pain following total knee arthroplasty: does the patellar cement-bone interface affect postoperative anterior knee pain?; Nickel allergy and total knee arthroplasty; The use of artificial intelligence for the prediction of periprosthetic joint infection following aseptic revision total knee arthroplasty; Ambulatory unicompartmental knee arthroplasty: development of a patient selection tool using machine learning; Femoral asymmetry: a missing piece in knee alignment; Needle arthroscopy – a benefit to patients in the outpatient setting; Can lateral unicompartmental knees be done in a day-case setting?

Anterior knee pain and/or radiological evidence of degeneration of the patellofemoral joint are considered to be contraindications to unicompartmental knee replacement. The aim of this study was to determine whether this is the case. Between January 2000 and September 2003, in 100 knees (91 patients) in which Oxford unicompartmental knee replacements were undertaken for anteromedial osteoarthritis, pre-operative anterior knee pain and the radiological status of the patellofemoral joint were defined using the Altman and Ahlback systems. Outcome was evaluated at two years with the Oxford knee score and the American Knee Society score. Pre-operatively 54 knees (54%) had anterior knee pain. The clinical outcome was independent of the presence or absence of pre-operative anterior knee pain. Degenerative changes of the patellofemoral joint were seen in 54 patients (54%) on the skyline radiographs, including ten knees (10%) with joint space obliteration. Patients with medial patellofemoral degeneration had a similar outcome to those without. For some outcome measures patients with lateral patellofemoral degeneration had a worse score than those without, but these patients still had a good outcome, with a mean Oxford knee score of 37.6 (SD 9.5). These results show that neither anterior knee pain nor radiologically-demonstrated medial patellofemoral joint degeneration should be considered a contraindication to Oxford unicompartmental knee replacement. With lateral patellofemoral degeneration the situation is less well defined and caution should be observed

Aims. Patellofemoral problems are a common complication of total knee arthroplasty. A high compressive force across the patellofemoral joint may affect patient-reported outcome. However, the relationship between patient-reported outcome and the intraoperative patellofemoral contact force has not been investigated. The purpose of this study was to determine whether or not a high intraoperative patellofemoral compressive force affects patient-reported outcome. Patients and Methods. This prospective study included 42 patients (42 knees) with varus-type osteoarthritis who underwent a bi-cruciate stabilized total knee arthroplasty and in whom the planned alignment was confirmed on 3D CT. Of the 42 patients, 36 were women and six were men. Their mean age was 72.3 years (61 to 87) and their mean body mass index (BMI) was 24.4 kg/m2 (18.2 to 34.3). After implantation of the femoral and tibial components, the compressive force across the patellofemoral joint was measured at 10°, 30°, 60°, 90°, 120°, and 140° of flexion using a load cell (Kyowa Electronic Instruments Co., Ltd., Tokyo, Japan) manufactured in the same shape as the patellar implant. Multiple regression analyses were conducted to investigate the relationship between intraoperative patellofemoral compressive force and patient-reported outcome two years after implantation. Results. No patient had anterior knee pain after total knee arthroplasty. The compressive force across the patellofemoral joint at 140°of flexion was negatively correlated with patient satisfaction (R2 = 0.458; β = –0.706; p = 0. 041) and Forgotten Joint Score-12 (FJS-12; R2= .378; β = –0.636; p = 0. 036). The compressive force across the patellofemoral joint at 60° of flexion was negatively correlated with the patella score (R2 = 0.417; β = –0.688; p = 0. 046). Conclusion. Patient satisfaction, FJS-12, and patella score were affected by the patellofemoral compressive force at 60° and 140° of flexion. Reduction of the patellofemoral compressive forces at 60° and 140° of flexion angle during total knee arthroplasty may improve patient-reported outcome, but has no effect on anterior knee pain

Introduction. The constitutional knee anatomy in the coronal plane includes the distal femoral joint line obliquity (DFJLO) which in most patients is in slight valgus positioning. Despite this native anatomy, the mechanical positioning of the femoral component during primary total knee arthroplasty (TKA) often ignores the native DFJLO opting to place the femur in a set degree of valgus that varies upon the practitioner's practice and experience. Unfortunately, this technique is likely to generate high rate of distal lateral femoral overstuffing. This anatomical mismatch might be a cause of anterior knee pain and therefore partly explain the adverse functional outcomes of mechanically aligned (MA) TKA. Our study aims at assessing the relationship between constitutional knee anatomy and clinical outcomes of MA TKA. We hypothesized that a negative relationship would be found between the constitutional frontal knee deformity, the distal femoral joint line obliquity, and functional outcomes of MA TKA with a special emphasize on patellofemoral (PF) specific outcomes. Methods. One hundred and thirteen patients underwent MA TKA (posterior-stabilized design) for primary end-stage knee osteoarthritis. They were prospectively followed for one year using the New KSS 2011 and HSS Patella score. Residual anterior knee pain was also assessed. Knee phenotypes using anatomical parameters (such as HKA, HKS, DFJLO and LDFA (Lateral distal femoral angle)) were measured from preoperative and postoperative lower-limb EOS® images (Biospace, Paris, France). We assessed the relationship between the knee anatomical parameters and the functional outcome scores at 1 year postoperatively. Results. We investigated four groups according to the preoperative obliquity of the distal femur and HKA. The group with high DFJLO and varus knee deformity demonstrated lower HSS scores (drop>10%, p=0.03) and higher rate of anterior knee pain (p=0.03). Higher postoperative variation of LDFA was associated with lower HSS scores (r = −0.2367, p=0.03) and with higher preoperative DFJLO (p=0.0001) due to the MA technique. Knee phenotypes with LDFA<87° presented higher risk of variation of LDFA. No correlation was found using New KSS 2011 outcomes at one-year follow-up. Discussion/Conclusion. Disregard of the constitutional knee anatomy (LDFA and DFJLO) when performing a MA TKA may generate a non-physiologic knee kinematics that impact patellofemoral outcomes and resulting in residual anterior knee pain. While these results are restricted to modern posterior-stabilized TKA design, recent in silico and in vitro studies supported the negative effect of the lateral overstuffing of the femoral component in the coronal plane during knee flexion. This study provides further evidence that suggest patient-specific anatomical considerations are needed to optimize component position and subsequent outcomes following primary TKA. Additional studies are needed to integrate the rotational status of the femoral component in this analysis. For any figures or tables, please contact authors directly

The efficacy of circumpatellar electrocautery in reducing the incidence of post-operative anterior knee pain is unknown. We conducted a single-centre, outcome-assessor and patient-blinded, parallel-group, randomised, controlled trial to compare circumpatellar electrocautery with no electrocautery in total knee replacement in the absence of patellar resurfacing. Patients requiring knee replacement for primary osteoarthritis were randomly assigned circumpatellar electrocautery (intervention group) or no electrocautery (control group). The primary outcome measure was the incidence of anterior knee pain. A secondary measure was the standardised clinical and patient-reported outcomes determined by the American Knee Society scores and the Western Ontario and McMaster Universities (WOMAC) osteoarthritis index. A total of 131 knees received circumpatellar electrocautery and 131 had no electrocautery. The overall incidence of anterior knee pain at follow-up at one year was 26% (20% to 31%), with 19% (12% to 26%) in the intervention group and 32% (24% to 40%) in the control group (p = 0.02). The relative risk reduction from electrocautery was 40% (9% to 61%) and the number needed to treat was 7.7 (4.3 to 41.4). The intervention group had a better mean total WOMAC score at follow-up at one year compared with the control group (16.3 (0 to 77.7) versus 21.6 (0 to 76.7), p = 0.04). The mean post-operative American Knee Society knee scores and function scores were similar in the intervention and control groups (knee score: 92.4 (55 to 100) versus 90.4 (51 to 100), respectively (p = 0.14); function score: 86.5 (15 to 100) versus 84.5 (30 to 100), respectively (p = 0.49)). Our study suggests that in the absence of patellar resurfacing electrocautery around the margin of the patella improves the outcome of total knee replacement

We have examined the differences in clinical outcome of total knee replacement (TKR) with and without patellar resurfacing in a prospective, randomised study of 181 osteoarthritic knees in 142 patients using the Profix total knee system which has a femoral component with features considered to be anatomical and a domed patellar implant. The procedures were carried out between February 1998 and November 2002. A total of 159 TKRs in 142 patients were available for review at a mean of four years (3 to 7). The patients and the clinical evaluator were blinded in this prospective study. Evaluation was undertaken annually by an independent observer using the knee pain scale and the Knee Society clinical rating system. Specific evaluation of anterior knee pain, stair-climbing and rising from a seated to a standing position was also undertaken. No benefit was shown of TKR with patellar resurfacing over that without resurfacing with respect to any of the measured outcomes. In 22 of 73 knees (30.1%) with and 18 of 86 knees (20.9%) without patellar resurfacing there was some degree of anterior knee pain (p = 0.183). No revisions related to the patellofemoral joint were performed in either group. Only one TKR in each group underwent a re-operation related to the patellofemoral joint. A significant association between knee flexion contracture and anterior knee pain was observed in those knees with patellar resurfacing (p = 0.006)

Aims. The aims of this study were to investigate the ability to kneel after total knee arthroplasty (TKA) without patellar resurfacing, and its effect on patient-reported outcome measures (PROMs). Secondary aims included identifying which kneeling positions were most important to patients, and the influence of radiological parameters on the ability to kneel before and after TKA. Methods. This prospective longitudinal study involved 209 patients who underwent single radius cruciate-retaining TKA without patellar resurfacing. Preoperative EuroQol five-dimension questionnaire (EQ-5D), Oxford Knee Score (OKS), and the ability to achieve four kneeling positions were assessed including a single leg kneel, a double leg kneel, a high-flexion kneel, and a praying position. The severity of radiological osteoarthritis (OA) was graded and the pattern of OA was recorded intraoperatively. The flexion of the femoral component, posterior condylar offset, and anterior femoral offset were measured radiologically. At two to four years postoperatively, 151 patients with a mean age of 70.0 years (SD 9.44) were included. Their mean BMI was 30.4 kg/m. 2. (SD 5.36) and 60 were male (40%). They completed EQ-5D, OKS, and Kujala scores, assessments of the ability to kneel, and a visual analogue scale for anterior knee pain and satisfaction. Results. The ability to kneel in the four positions improved in between 29 (19%) and 53 patients (35%) after TKA, but declined in between 35 (23%) and 46 patients (30%). Single-leg kneeling was most important to patients. After TKA, 62 patients (41%) were unable to achieve a single-leg kneel, 76 (50%) were unable to achieve a double-leg kneel, 102 (68%) were unable to achieve a high-flexion kneel and 61 (40%) were unable to achieve a praying position. Posterolateral cartilage loss significantly affected preoperative deep flexion kneeling (p = 0.019). A postoperative inability to kneel was significantly associated with worse OKS, Kujala scores, and satisfaction (p < 0.05). Multivariable regression analysis identified significant independent associations with the ability to kneel after TKA (p < 0.05): better preoperative EQ-5D and flexion of the femoral component for single-leg kneeling; the ability to achieve it preoperatively and flexion of the femoral component for double-leg kneeling; male sex for high-flexion kneeling; and the ability to achieve it preoperatively, anterior femoral offset, and patellar cartilage loss for the praying position. Conclusion. The ability to kneel was important to patients and significantly influenced knee-specific PROMs, but was poorly restored by TKA with equal chances of improvement or decline. Cite this article: Bone Joint J 2021;103-B(9):1514–1525

Background. Secondary osteonecrosis of the knee (SOK) generally occurs in relatively young patients in their working years; at advanced stages of SOK, the only viable surgical option is total knee arthroplasty (TKA). We conducted a retrospective study to investigate implant survivorship, clinical and radiographic outcomes, and complications of cemented TKA with/without patellar resurfacing for SOK. Methods. Thirty-eight cemented TKAs in 27 patients with non-traumatic SOK with a mean age 43 years (range 17–65) were retrospectively reviewed. Twenty-one patients (78%) were female. Mean body mass index was 31 kg/m. 2. (range 20–48); 11 patients (41%) received bilateral TKAs. Twenty patients (74%) had a history of corticosteroid use and 18% had a history of alcohol abuse. Patellar osteonecrosis was coincidentally found in six knees (16%), all of which had no anterior knee pain and had no patellofemoral joint collapse. The mean follow-up was 7 years (range 2–12). Knee Society Score (KSS) and radiographic outcomes were evaluated at 6 weeks, 1 year, then every 2–3 years thereafter. Results. Ninety-two percent had implant survivorship free from revision with significant improvement in KSS. Causes of revision included aseptic tibial loosening (one), deep infection (one), and instability with patellofemoral issues (one). Four of six cases also with patellar osteonecrosis received resurfacing, including one with a periprosthetic patellar fracture after minor trauma, with satisfactory clinical results after conservative treatment. None of the unrevised knees had progressive radiolucent lines or evidence of loosening. Non-resurfacing of the patella, use of a stem extension or a varus-valgus constrained prosthesis constituted 18%, 8% and 3% of knees, respectively. Conclusion. Cemented TKAs with selective stem extension in patients with SOK had satisfactory implant survivorship and reliable outcomes at a mean of 7 years. Patellar resurfacing is unnecessary in younger patients with no symptoms of anterior knee pain and no patellar collapse radiographically. For any figures or tables, please contact the authors directly

Background. Hoffa pad in Total knee replacement is a mystery. Very few studies have been carried out and no obvious results have been achieved. Aim. Our aim was to compare the clinical value of the Hoffa pad including blood loss, range of motion, anterior knee pain and swelling post total knee replacement. Method. this study has been designed as prospective randomized control trial, with involvement of 4 surgeons, with no exclusion criteria and no special preparation for the patients. Results. with 100 patients results, it has been found that by leaving the Hoffa pad well alone, there were increase of range of motion post TKR by 5 to 10 degrees, there were decrease of blood loss by 50%, no difference in swelling, and most patients with Hoffa pad had almost no anterior knee pain. Conclusion. the study is in a very early stage to draw a concrete conclusion, however early results showed that Hoffa pad can play a huge role in lubrication, anterior knee pain and finally in reducing blood loss

Abstract. Introduction. Total knee replacement (TKR) in patients with skeletal dysplasia is technically challenging surgery due to deformity, joint contracture, and associated co-morbidities. The aim of this study is to follow up patients with skeletal dysplasia following a TKR. Methodology. We retrospectively reviewed 22 patients with skeletal dysplasia who underwent 31 TKRs at our institution between 2006 and 2022. Clinical notes, operative records and radiographic data were reviewed. Results. Achondroplasia was the most common skeletal dysplasia (8), followed by Chondrodysplasia punctata (7) and Spondyloepiphyseal dysplasia (5). There were fourteen men and eight women with mean age of 51 years (28 to 73). The average height of patients was 1.4 metres (1.16–1.75) and the mean weight was 64.8 Kg (34.3–100). The mean follow up duration was 68.32 months (1–161). Three patients died during follow up. Custom implants were required in twelve patients (38.71%). Custom jigs were utilised in six patients and two patients underwent robotic assisted surgery. Hinged TKR was used in seventeen patients (54.84%), posterior stabilised TKR in nine patients (29.03%), and cruciate retaining TKR in five patients (16.13%). One patient underwent a patella resurfacing for persistent anterior knee pain and another had an intra-operative medial tibial plateau fracture which was managed with fixation. No revisions occurred during the follow up period. Conclusion. Despite the technical challenges and complexity of TKR within this unique patient group, we demonstrate good implant survivorship during the study period. Cross sectional imaging is recommended preoperatively for precise planning and templating

Abstract. Introduction. Anterior cruciate ligament reconstruction (ACLR) can be performed with a number of different autografts including all soft tissue quadriceps autograft. (QT). QT has several advantages including decreased donor site morbidity, reduced anterior knee pain and comparable revision rates compared to other autografts. The primary aim of this review was to assess all complications of QT in adult population. Methodology. A systematic review of the literature was conducted on in accordance with the PRISMA guidelines using the online databases Medline and EMBASE. Clinical studies or reporting on soft tissue QT were included and appraised using the Methodological Index for Non-Randomized Studies (MINORS) tool. Results. Twelve studies were eligible, giving a total of 774 cases of QT ACLR. The mean age ranged from 18 to 45 years. The mean follow-up ranged from 12 to 55.6 months. Nine studies report on patients’ functional outcomes with mean IKDC score was 90.9 ±22.6 and Lysholm score of 88.6 ±6.5. Seven studies reported on complications which was overall 12.3% including 4.1% for graft site morbidity. Infection was reported in 0.4% of the patients. Seven studies reported on failure rate which was reported in 5.3%. Re-operation rate for any reason was 3.2 %. Conclusion. All soft tissue QT for ACLR has a low complication rate and revision rate. There is less graft site morbidity

Abstract. Introduction. With respect to survivorship following total knee arthroplasty (TKA), joint registries consistently demonstrate higher revision rates for both sexes in those less than 55 years. The current study analyses the survivorship of 500 cementless TKAs performed in this age group in a high-volume primary joint unit where cementless TKA has traditionally been used for the majority of patients. Methods. This was a retrospective review of 500 consecutive TKAs performed in patients under the age of 55 between March 1994 and April 2017. The primary outcome measure for the study was all-cause revision. Secondary outcome measures included clinical, functional and radiological outcomes. Results. The all-cause revision rate was 1.6% (n=8) at a median of 55.7 months. Four were revised for infection, 2 for stiffness, 1 for aseptic loosening of the tibial component and 1 patella was resurfaced for anterior knee pain. The aseptic revision rate was 0.8% (n=4). Twenty-seven (5.4%) patients underwent a manipulation under anaesthetic (MUA). Including those who underwent MUA, 6.8% (n=34) underwent other non-revision procedures. Conclusion. Survivorship in our unit in this young patient cohort was excellent with an aseptic revision rate of 0.8% at 59.7 months using a fully cementless construct. The MUA rate was higher than expected

Introduction. Total knee replacement (TKR) is an established and effective surgical procedure in case of advanced osteoarthritis. However, the rate of satisfied patients amounts only to about 75 %. One common cause for unsatisfied patients is the anterior knee pain, which is partially caused by an increase in patellofemoral contact force and abnormal patellar kinematics. Since the malpositioning of the tibial and the femoral component affects the interplay in the patellofemoral joint and therefore contributes to anterior knee pain, we conducted a computational study on a cruciate-retaining (CR) TKR and analysed the effect of isolated femoral and tibial component malalignments on patellofemoral dynamics during a squat motion. Methods. To analyse different implant configurations, a musculoskeletal multibody model was implemented in the software Simpack V9.7 (Simpack AG, Gilching, Germany) from the SimTK data set (Fregly et al.). The musculoskeletal model comprised relevant ligaments with nonlinear force-strain relation according to Wismans and Hill-type muscles spanning the lower extremity. The experimental data were obtained from one male subject, who received an instrumented CR TKR. Muscle forces were calculated using a variant of the computed muscle control algorithm. To enable roll-glide kinematics, both tibio- and patellofemoral joint compartments were modelled with six degrees of freedom by implementing a polygon-contact-model representing the detailed implant surfaces. Tibiofemoral contact forces were predicted and validated using data from experimental squat trials (SimTK). The validated simulation model has been used as reference configuration corresponding to the optimal surgical technique. In the following, implant configurations, i.e. numerous combinations of relative femoral and tibial component alignment were analysed: malposition of the femoral/tibial component in mediolateral (±3 mm) and anterior-posterior (±3 mm) direction. Results. Mediolateral translation/malposition of the tibial component did not show high influence on the maximal patellofemoral contact force. Regarding the mediolateral translation of the femoral component, similar tendencies were observed. However, lateralisation of the femoral component (3 mm) clearly increased the lateral patella shift and medialisation of the tibial component (3 mm) led to a slightly increased lateral patella shift. Compared to the reference model, pronounced posterior translation of the tibial and femoral component resulted in a lower patellofemoral contact force, further increasing with higher anterior translation of the components. The translation of the tibial component showed smaller influence on the patellofemoral contact force than the translation of the femoral component. Discussion. In our present study, the mediolateral malposition of the femoral and tibial component showed no major impact on patellofemoral contact force and contribution to anterior knee pain in patients with CR TKR. However, the influence of implant component positioning in anterior-posterior direction on patellofemoral contact force is evident, especially for the femoral component. Our generated musculoskeletal model can contribute to computer-assisted preclinical testing of TKR and may support clinical decision-making in preoperative planning

To determine in skeletally mature patients with a traumatic, first-time, patellar dislocation, the effect of early MPFL reconstruction versus rehabilitation on the rate of recurrent patellar dislocations and functional outcomes. Three online databases MEDLINE, EMBASE and PubMed were searched from database inception (1946, 1974, 1966 respectively), to August 20th, 2021, for literature addressing the management of patients sustaining acute first-time patellar dislocations. Data on redislocation rates, functional outcomes using the Kujala score, and complication rates were recorded. A meta-analysis was used to pool the mean postoperative kujala score as well as calculate the proportion of patients sustaining redislocation episodes using a random effects model. A risk of bias assessment was performed for all included studies using the MINORS and Detsky scores. Overall, there were a total of 22 studies and 1705 patients included in this review. The pooled mean redislocation rate in 18 studies comprising 1409 patients in the rehabilitation group was 31% (95% CI 25%-36%, I2 = 65%). Moreover, the pooled mean redislocation rate in five studies comprising 318 patients undergoing early MPFL reconstruction was 7% (95% CI 2%-17%, I2 = 70%). The pooled mean postoperative Kujala anterior knee pain score in three studies comprising 67 patients in the reconstructive group was 91 (95% CI 84-97, I2 = 86%), compared to a score of 81 (95% CI 78-85, I2 = 78%) in 7 studies comprising 332 patients in the rehabilitation group. The reoperation rate was 9.0% in 936 patients in the rehabilitation group and 2.2% in 322 patients in the reconstruction group. Management of acute first-time patellar dislocations with MPFL reconstruction resulted in a lower rate of redislocation and a higher Kujala score, as well as noninferiority with respect to complication rates compared to nonoperative treatment. The paucity of high-level evidence warrants further investigation in this topic in the form of well-designed and high-powered RCTs to determine the optimal management option in these patients

Traditional dogma states that anterior knee pain in adolescence does not lead to patello-femoral arthritis. However analysis of 642 new knee referrals seen in one year showed that over 25% had anterior knee pain and that patients were of all ages. This lead to us questioning whether anterior knee pain or adolescent chondromalacia patellae is in fact a benign self limiting condition. Method: A postal questionnaire was sent to 150 patients who had undergone isolated patello femoral replacement (PFR) enquiring about patella problems earlier in life. The same questionnaire was sent to a matched group of patients who had undergone unicompartmental replacement; because of the selection policy of the unit, these would not have had changes of patellofemoral arthritis. Results: 118 patients who had undergone PFR retumed the form. 107 were female; the average age at surgery was 66 years. 26 (22%) reported adolescent anterior knee pain at an average age of 18. 112 forms were returned form the UKR group in which females predominated and who had an average age at surgery of 67 years. Only 7 (6%) reported adolescent anterior knee pain, at an average age of 19. 16 (14%) of the PFR group reported adolescent patella instability as opposed to 1 on the UKR group. Discussion: The finding that significantly more patients with isolated patello-femoral arthritis had suffered from adolescent anterior knee pain suggests a possible causal relationship. Further long-term studies are needed to determine whether adolescent anterior knee pain is benign, as traditionally believed, or whether certain subsets are precursors of patello-femoral arthritis

Patella subluxation assessed on dynamic MRI has previously been shown to be associated with anterior knee pain. In this MRI study of 60 patients we investigated the relationship between subluxation and multiple bony, cartilaginous and soft-tissue factors that might predispose to subluxation using discriminant function analysis. Patella engagement (% of patella cartilage overlapping with trochlea cartilage) had the strongest relationship with subluxation. Patellae with > 30% engagement tended not to sublux; those with < 30% tended to sublux. Other factors that were associated with subluxation included the tibial tubercle-trochlea notch distance, vastus medialis obliquus distance from patella, patella alta, and the bony and cartilaginous sulcus angles in the superior part of the trochlea. No relationship was found between subluxation and sulcus angles for cartilage and bone in the middle and lower part of the trochlea, cartilage thicknesses and Wiberg classification of the patella. This study indicates that patella engagement is a key factor associated with patellar subluxation. This suggests that in patients with anterior knee pain with subluxation, resistant to conservative management, surgery directed towards improving patella engagement should be considered. A clinical trial is necessary to test this hypothesis

Abstract. Objectives. The outcomes from patella fracture have remained dissatisfactory despite advances in treatment, especially from operative fixation1. Frequently, reoperation is required following open reduction and internal fixation (ORIF) of the patella due to prominent hardware since the standard technique for patella ORIF is tension band wiring (TBW) which inevitably leaves a bulky knot and irritates soft tissue given the patella's superficial position2. We performed a systematic review to determine the optimal treatment of patella fractures in the poor host. Methods. Three databases (EMBASE/Medline, ProQuest and PubMed) and one register (Cochrane CENTRAL) were searched. 476 records were identified and duplicates removed. 88 records progressed to abstract screening and 73 were excluded. Following review of complete references, 8 studies were deemed eligible. Results. Complication rates were shown to be high in our systematic review. Over one-fifth of patients require re-operation, predominantly for removal of symptomatic for failed hardware. Average infection rate was 11.95% which is higher than rates reported in the literature for better hosts. Nevertheless, reported mortality was low at 0.8% and thromboembolic events only occurred in 2% of patients. Average range of movement achieved following operative fixation was approximately 124 degrees. Upon further literature review, novel non-operative treatment options have shown acceptable results in low-demand patients, including abandoning weight-bearing restrictions altogether and non-operatively treating patients with fracture gaps greater than 1cm. Regarding operative management, suture/cable TBW has been investigated as a viable option with good results in recent years since the materials used show comparable biomechanics to stainless steel. Additionally, ORIF with locking plates have shown favourable results and have enabled aggressive post-operative rehabilitation protocols. TBW with metallic implants has shown higher complication rates, especially for anterior knee pain, reoperation and poor functional outcomes. Conclusion. There is sparse literature regarding patella fracture in the poor host. Nevertheless, it is clear that ORIF produces better outcomes than conservative treatment but the optimal technique for patella ORIF remains unclear. TBW with metallic implants should not remain the standard technique for ORIF; low-profile plates of suture TBW are more attractive solutions. Non-operative treatment may be considered for low-demand individuals however any form of patellectomy should be avoided if possible. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Abstract. Objective. A common orthopaedic pain found in a wide spectrum of individuals, from young and active to the elderly is anterior knee pain (AKP). It is a multifactorial disorder which is thought to occur through muscular imbalance, overuse, trauma, and structural malalignment. Over time, this can result in cartilage damage and subsequent chondral lesions. Whilst the current gold standard for chondral lesion detection is MRI, it is not a highly sensitive tool, with around 20% of lesions thought to be mis-diagnosed by MRI. Single-photon emission computerised tomography with conventional computer tomography (SPECT/CT) is an emerging technology, which may hold clinical value for the detection of chondral lesions. SPECT/CT may provide valuable diagnostic information for AKP patients who demonstrate absence of structural change on other imaging modalities. This review systematically assessed the value of SPECT/CT as an imaging modality for knee pain, and its ability to diagnose chondral lesions for patients who present with knee pain. Methods. Using PRISMA guidelines, a systematic search was carried out in PubMed, Science Direct, and Web of Knowledge, CINAHL, AMED, Ovid Emcare and Embase. Inclusion criteria consisted of any English language article focusing on the diagnostic value of SPECT/CT for knee chondral lesions and knee pain. Furthermore, animal or cadaver studies, comparator technique other than SPECT/CT or patients with a pathology other than knee chondral lesions were excluded from the study. Relevant articles underwent QUADAS-2 bias assessment. Results. 11,982 manuscripts were identified, and the titles were screened for relevance. Seven studies were selected as being appropriate and were subjected to QUADAS-2 assessment. All 7 articles scored low for bias. Two papers deemed that the ICRS score of chondral lesions at intraoperative assessment correlated with SPECT/CT tracer uptake. Two studies concluded that MRI significantly correlated with SPECT/CT tracer uptake, with some instances whereby SPECT/CT identified more chondral lesions than MRI. Two papers compared bone scintigraphy (BS) to SPECT/CT and concluded that SPECT/CT was not only able to identify more chondral lesions than BS, but also localise and characterise the lesions. Conclusion. Evidence implies that SPECT/CT may be a useful imaging modality for the detection and localisation of cartilage lesions, particularly in discrepant cases whereby there is an absence of lesions on other imaging modalities, or a lack of correspondence with patients’ symptoms. More studies would be of value to confirm the conclusions of this review. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Resurfacing the patella is performed the majority of the time in the United States and in many regions it is considered standard practice. In many countries, however, the patella is left un-resurfaced an equal amount of the time or even rarely ever resurfaced. Patella resurfacing is not a simple or benign procedure. There are numerous negative sequelae of resurfacing including loosening, fragmentation, avascular necrosis, lateral facet pain, stress fracture, acute fracture, late fracture, and restricted motion. In a study by Berend, Ritter, et al, failures of the patella component were reported 4.2% of the time at an average of only 2.6 years. A study was undertaken at Washington University in recent years to determine rather more clinical problems were observed following total knee replacement with or without patella resurfacing. Records were maintained on all problem total knees cases with well localised anterior knee pain. The referral area for this clinic is St. Louis which is among the largest American cities, with the highest percentage of total knees that are performed without patella resurfacing. During 4 years of referrals of total knee patients with anterior knee pain, 47 cases were identified of which 36 had a resurfaced patella and 11 had a non-resurfaced patella. Eight of 36 resurfaced patellae underwent surgery while only 2 of 11 non-resurfaced patellae underwent subsequent surgery. More than 3 times as many painful total knees that were referred for evaluation had already had their patella resurfaced. In spite of the fact that approximately equal number of total knees were performed in this area without patella resurfacing, far more patients presented to clinic with painful total knee in which the patella had been resurfaced. The numerous pathologies requiring a treatment following patella resurfacing included patella loosening, fragmentation of the patella, avascular necrosis patella, late stress fracture, lateral facet pain, oblique resurfacing, and too thick of a patellar composite. In a large multi-center randomised clinical trial at 5 years from the United Kingdom in over 1700 knees from 34 centers and 116 surgeons, there was no difference in the Oxford Score, SF-12, EQ-5D, or need for further surgery or complications. The authors concluded, “We see no difference in any score, if there is a difference, it is too small to be of any clinical significance”. In a prospective of randomised clinical trial performed at Tulane University over 20 years ago, no differences were observed in knee score, a functional patella questionnaire, or the incidence of anterior knee pain between resurfaced and un-resurfaced patellae at time intervals of 2–4 years, 5–7 years, or greater than 10 years. Beyond 10 years the knee scores of total knee patients with a resurfaced patella had declined significantly greater than those with a non-resurfaced patella. There are numerous advantages of not resurfacing the patella including less surgical time, less expense, a lower risk of “major” complications (especially late complications), and if symptoms develop in an un-resurfaced patella, it is an easier salvage situation with more options available. A small percentage of total knee patients will be symptomatic whether or not their patella is resurfaced. Not resurfacing the patella retains more options and has fewer complications. The major determinant of clinical result and the presence of anterior knee pain after knee replacement is surgical technique and component design not whether or not the patella is resurfaced. Patella resurfacing is occasionally necessary for patients with inflammatory arthritis, a deformed or maltracking patella, or symptoms and pathology that are virtually restricted to the patellofemoral joint. For the vast majority of patients, however, patella resurfacing is not necessary

The decision to resurface the patella has been well studied. While regional differences exist, the overwhelming choice by most Surgeons in the United States is to resurface the patella. Data supports that this is the correct choice. Articular cartilage on metal has not been shown to be a good long term bearing surface. Cushner et al. has also shown that cartilage in the arthritic knee has significant pathologic abnormalities. Patella surfacing has excellent long-term results with a low complication rate. Anterior knee pain is a common complaint after knee replacement and is even more common in TKA with un-resurfaced patella. Pakos et al. had more reoperations and greater anterior knee pain when the patella was NOT resurfaced. Parvizi et al. also found less patient satisfaction with un-resurfaced patellas. Meta-analysis results indicate higher revision rates with un-resurfaced patellas. Bilateral knee studies also favor resurfaced patella. Higher revision rates were also confirmed in the Swedish Registry with a 140% higher revision rate in TKA with un-resurfaced patellas In addition, second operations to resurface the patella often are unsuccessful at alleviating pain. Surgeons who choose not to resurface the patella must accept that their patients will have the same or greater degree of anterior knee pain and a significantly greater risk for reoperation

The management of the patella during total knee replacement is controversial. In some studies the absence of patellar resurfacing results in residual anterior knee pain in over 10% of patients. One form of treatment which may be used in an endeavour to reduce this is circumferential patellar rim electrocautery. This is believed to partially denervate the patella. However, there is no evidence of the efficacy of this procedure, nor do we know if it results in harm. A retrospective comparative cohort study was performed of 192 patients who had undergone a primary total knee replacement with the porous coated Low Contact Stress rotating platform prosthesis without patellar resurfacing between 2003 and 2007. In 98 patients circumferential electrocautery of the patellar rim was performed and in 94 patients it was not. The two groups were matched for gender and age. The general Oxford Knee Score and the more specific patellar score for anterior knee pain were used to assess patient outcomes a minimum of two years post-operatively. No statistically significant differences were noted between the groups for either scoring system (p = 0.41 and p = 0.87, respectively). Electrocautery of the patella rim did not improve the outcome scores after primary total knee replacement in our patients

We investigated the association between the radiological findings and the symptoms arising from the patellofemoral joint in advanced osteoarthritis (OA) of the knee. Four radiological features, joint space narrowing, osteophyte formation, translation of the patella and focal attrition were assessed in 151 consecutive osteoarthritic knees in 107 patients undergoing total knee replacement. The symptoms which were assessed included anterior knee pain which was scored, the ability to rise from a chair and climb stairs, and quadriceps weakness. Among the radiological features, only patellar translation and obliteration of the joint space had a statistically significant association with anterior knee pain (odds ratio (OR) 4.85; 95% confidence interval (CI) 1.83 to 12.88 and OR 11.23; 95% CI 2.44 to 51.62) respectively. Patellar translation had a statistically significant association with difficulty in rising from a chair (OR 9.06; 95% CI 1.75 to 45.11). Other radiological features, including osteophytes, joint space narrowing, and focal attrition had no significant association. Our study indicates that the radiological findings of patellar translation and significant loss of cartilage are predictive of patellofemoral symptoms and functional limitation in advanced OA of the knee

Purpose: The purpose of this study was to determine the clinical and radiographic outcomes at a minimum follow-up of ten years of patients who underwent a total knee arthroplasty with an inset patellar component. The incidence of anterior knee pain and the factors which may contribute to were also studied. Method: Patients who had genesis I/II TKA with an inset patellar button with a minimum follow-up of 10 years were identified. 448 patients with 521 knees were identified. Patients were excluded if they were deceased, had incomplete data, were unable to be contacted or had a known or impending revision. Those who had revision were included in a Kaplan-Meier survivorship analysis. The included patients, deceased patients and those lost to follow-up were named group1, 2, and 3 respectively. Demographics and Knee society scores(KSS) were studies for all 3 groups. This was to identify any exclusion bias. Presence and severity of anterior knee pain as well as radiographic factors were collected for group 3. Logistic regression analysis was used to identify and variables that influenced the KSS and presence of anterior knee pain. Kaplan-Meier survivorship analysis was performed for patellar revision and tibial/femoral revision endpoints. Results: 144 patients with 175 TKA were included in this study. They were on average 66 years old, 64% female, had a BMI of 30 and had a diagnosis of OA 92% of the time. Their average f/u was 11.3 years. Groups 2 and 3 had similar demographics but of course a much shorter f/u. Group 1 had a pre-op KSS of 84 a post-op KSS of 151 and a KS change score of 67. Groups 2 and 3 had similar pre-op, post-op and KSS change scores. We found anterior knee pain occurred in 5% of patients with an average severity of 5/10. Linear regression analysis did not identify any variables including radiographic parameters that had an independent influence on KSS or anterior knee pain. Kaplan-Meier survivorship with patellar revision for any reason as an endpoint was 96% at 10 years and 94% at 17 years. 20 patella were known to have had a revision or were undergoing a revision. Conclusion: We conclude that use of an inset patellar component can give excellent durable results over time with a low rate of anterior knee pain and complications

Introduction. Snapping hip syndrome is a common condition affecting 10% of the population. It is due to the advance of the iliotibial band (ITB) over the greater trochanter during lower limb movements and often associated with hip overuse, such as in athletic activities. Management is commonly conservative with physiotherapy or can be surgical to release the ITB. Here we carry out a systematic review into published surgical management and present a case report on an overlooked cause of paediatric snapping hip syndrome. Materials & Methods. A systematic review looking at published surgical management of snapping hip was performed according to PRISMA guidelines. PubMed, MEDLINE, EMBASE, CINAHL and the Cochrane Library databases were searched for “((Snapping hip OR Iliotibial band syndrome OR ITB syndrome) AND (Management OR treatment))”. Adult and paediatric published studies were included as few results were found on paediatric snapping hip alone. Results. 1548 studies were screened by 2 independent reviewers. 8 studies were included with a total of 134 cases, with an age range of 14–71 years. Surgical management ranged from arthroscopic, open or ultrasound guided release of the ITB, as well as gluteal muscle releases. Common outcome measures showed statistically significant improvement pre- and post-operatively in visual analogue pain score (VAPS) and the Harris Hip Score (HHS). VAPS improved from an average of 6.77 to 0.3 (t-test p value <0.0001) and the HHS improved from an average of 62.6 to 89.4 (t-test p value <0.0001). Conclusions. Although good surgical outcomes have been reported, no study has reported on the effect of rotational profile of the lower limbs and snapping hip syndrome. We present the case of a 13-year-old female with snapping hip syndrome and trochanteric pain. Ultrasound confirmed external snapping hip with normal soft tissue morphology and radiographs confirmed no structural abnormalities. Following extensive physiotherapy and little improvement, she presented again aged 17 with concurrent anterior knee pain, patella mal-tracking and an asymmetrical out-toeing gait. CT rotational profile showed 2° of femoral neck retroversion and excessive external tibial torsion of 52°. Consequently, during her gait cycle, in order to correct her increased foot progression angle, the hip has to internally rotate approximately 35–40°, putting the greater trochanter in an anterolateral position in stance phase. This causes the ITB to snap over her abnormally positioned greater trochanter. Therefore, to correct rotational limb alignment, a proximal tibial de-rotation osteotomy was performed with 25° internal rotation correction. Post-operatively the patient recovered well, HHS score improved from 52.5 to 93.75 and her snapping hip has resolved. This study highlights the importance of relevant assessment and investigation of lower limb rotational profile when exploring causes of external snapping hip, especially where ultrasound and radiographs show no significant pathology

The decision to resurface the patella has been well studied. While regional differences exist, the overwhelming choice by most surgeons in the United States is to resurface the patella. Data supports that this is the correct choice. Articular cartilage on metal has not been shown to be a good long term bearing surface. Cushner et al has also shown that cartilage in the arthritic knee has significant pathologic abnormalities. Patella surfacing has excellent long-term results with a low complication rate. Anterior knee pain is a common complaint after knee replacement and is even more common in TKA with unresurfaced patella. Pakos et al had more reoperations and greater anterior knee pain when the patella was NOT resurfaced. Parvizi et al also found less patient satisfaction with unresurfaced patellas. Meta-analysis results indicate higher revision rates with unresurfaced patellas. Bilateral knee studies also favor resurfaced patella. Higher revision rates were also confirmed in the Swedish Registry with a 140% higher revision rate in TKA with unresurfaced patellas. In addition second operations to resurface the patella often are unsuccessful at alleviating pain. Surgeons who choose not to resurface the patella must accept that their patients will have the same or greater degree of anterior knee pain and a significantly greater risk for reoperation

Patellar resurfacing in total knee arthroplasty remains controversial. We report the medium term results of patients who had Scorpio total knee replacement for osteoarthritis between January 2002 and September 2004. A retrospective review of 118 patients was undertaken. All patients during the first half of this time period had no resurfacing of the patella, and all patients in the later half of this period underwent resurfacing of the patella. The mean follow-up in the non-resurfaced group was 30 months and the mean follow-up in the resurfaced group was 17 months. The two groups were similar in age, gender and the grade of the surgeon. Knee society clinical rating score, patient satisfaction, anterior knee pain, patellofemoral questionnaires, patellofemoral revision rates and success in returning to normal daily activities were noted. There was a significant difference between the two groups in the patellar revision rates, anterior knee pain and Euroquol scores. The incidence of anterior knee pain in the patella non-resurfaced group was 23%, compared to 6% in the resurfaced group [p<0.05]. The rate of revision in the non-resurfaced group was 11% compared to 0% in the resurfaced group [p=0.03]. The mean Euroquol score in the resurfaced group was 86.44 compared to 80.35 [p=0.04]. Knee Society score, patient satisfaction, symptoms of patellar apprehension and knee instability, return to pre-op functional level, ability to kneel, use of a walking aid, presence of limp and satisfaction with operation as not statistically different between the two groups. In view of the statistically significant difference in the incidence of anterior knee pain and the rate of revision in the group of patients without patellar resurfacing, the authors suggest that retaining the patellar surface may not be a viable option. Although an appropriate design for the femoral prosthetic trochlea is an important factor, a good surgical technique with patellar resurfacing is more likely to result in predictable satisfactory results. We feel that high contact pressures between the non-resurfaced patellae and the prosthetic femoral trochlea can be generated after a total knee replacement when the patella is not resurfaced, and can thus result in patients having anterior knee pain

Resurfacing the patella is performed the majority of the time in the US and in many regions it is considered standard practice. In many countries, however, the patella is left unresurfaced an equal amount of the time or even rarely ever resurfaced. Patella resurfacing is not a simple or benign procedure. There are numerous negative sequelae of resurfacing including loosening, fragmentation, avascular necrosis, lateral facet pain, stress fracture, acute fracture, late fracture, and restricted motion. In a study by Berend, Ritter, et al, failures of the patella component were reported 4.2% of the time at an average of only 2.6 years. A study was undertaken at Washington University in recent years to determine whether more clinical problems were observed following total knee replacement with or without patella resurfacing. Records were maintained on all problem total knees cases with well localised anterior knee pain. The referral area for this clinic is St. Louis which is among the largest American cities, with the highest percentage of total knees that are performed without patella resurfacing. During 4 years of referrals of total knee patients with anterior knee pain, 47 cases were identified of which 36 had a resurfaced patella and 11 had a non-resurfaced patella. Eight of 36 resurfaced patellae underwent surgery while only 2 of 11 non-resurfaced patellae underwent subsequent surgery. More than 3 times as many painful total knees that were referred for evaluation had already had their patella resurfaced. In spite of the fact that approximately equal number of total knees were performed in this area without patella resurfacing, far more patients presented to clinic with painful total knee in which the patella had been resurfaced. The numerous pathologies requiring a treatment following patella resurfacing included patella loosening, fragmentation of the patella, avascular necrosis patella, late stress fracture, lateral facet pain, oblique resurfacing, and too thick of a patellar composite. In a large multi-center randomised clinical trial at 5 years from the United Kingdom in over 1700 knees from 34 centers and 116 surgeons, there was no difference in the Oxford Score, SF-12, EQ-5D, or need for further surgery or complications. The authors concluded, “We see no difference in any score, if there is a difference, it is too small to be of any clinical significance”. In a prospective randomised clinical trial performed at Tulane University over 20 years ago, no differences were observed in knee score, a functional patella questionnaire, or the incidence of anterior knee pain between resurfaced and unresurfaced patellae at time intervals of 2–4 years, 5–7 years, or greater than 10 years. Beyond 10 years the knee scores of total knee patients with a resurfaced patella had declined significantly greater than those with a non-resurfaced patella. There are numerous advantages of not resurfacing the patella including less surgical time, less expense, a lower risk of “major” complications (especially late complications), and if symptoms develop in an unresurfaced patella, it is an easier salvage situation with more options available. A small percentage of total knee patients will be symptomatic whether or not their patella is resurfaced. Not resurfacing the patella retains more options and has fewer complications. The major determinant of clinical result and the presence of anterior knee pain after knee replacement is surgical technique and component design not whether or not the patella is resurfaced. Patella resurfacing is occasionally necessary for patients with inflammatory arthritis, a deformed or maltracking patella, or symptoms and pathology that are virtually restricted to the patellofemoral joint. For the vast majority of patients, however, patella resurfacing is not necessary

There is a lack of information about the association between patellofemoral osteoarthritis (PFOA) and both adolescent Anterior Knee Pain (AKP) and previous patellar dislocations. This case-control study involved 222 participants from our knee arthroplasty database answering a questionnaire. 111 patients suffering PFOA were 1:1 matched with a unicompartmental tibiofemoral arthritis control group. Multivariate correlation and binary logistic regression analysis was performed, with odds ratios (ORs) and 95% confidence intervals (CIs) calculated. This analysis helps us assess the effect of both variables whilst adjusting for major confounders, such as previous surgery and patient-reported instability. An individual is 7.5 times more likely to develop PFOA if they have suffered adolescent AKP (OR 7.5, 95% CIs 1.51–36.94). Additionally, experiencing a patellar dislocation increases the likelihood of development of PFOA, with an adjusted odds ratio of 3.2 (95% CIs 1.25–8.18). A 44-year difference in median age of first dislocation was also observed between the groups. This should bring into question the traditional belief that adolescent anterior knee pain is a benign pathology. Patellar dislocation is also a significant risk factor. These patients merit investigation, we encourage clinical acknowledgement of the potential consequences when encountering patients suffering from anterior knee pain or patellar dislocation

Abstract. Background. Conventional TKR aims for neutral mechanical alignment which may result in a smaller lateral distal femoral condyle resection than the implant thickness. We aim to explore the mismatch between implant thickness and bone resection using 3D planning software used for Patient Specific Instrumentation (PSI) TKR. Methods. This is a retrospective anatomical study from pre-operative MRI 3D models for PSI TKR. Cartilage mapping allowed us to recreate the native anatomy, enabling us to quantify the mismatch between the distal lateral femoral condyle resection and the implant thickness. Results. We modelled 292 knees from PSI TKR performed between 2012 and 2015. There were 225 varus knees and 67 valgus knees, with mean supine hip-knee-angle of 5.6±3.1 degrees and 3.6±4.6 degrees, respectively. In varus knees, the mean cartilage loss from medial and lateral femoral condyle was 2.3±0.7mm and 1.1±0.8mm respectively; the mean overstuffing of the lateral condyle 1.9±2.2mm. In valgus knees, the mean cartilage loss from medial and lateral condyle was 1.4±0.8mm and 1.5±0.9mm respectively; the mean overstuffing of the lateral condyle was 4.1±1.9mm. Conclusions. Neutral alignment TKR often results in overstuffing of the lateral condyle. This may increase the patello-femoral pressure at the lateral facet in flexion. Anterior knee pain may be persistent even after patellar resurfacing due to tight lateral retinacular structures. An alternative method of alignment such as anatomic alignment may minimise this problem

To resurface or not to resurface the patella… that is the question. It all comes down to where you practice. It is controversial in that there is a risk of possible complications from resurfacing versus the potential for simply having complaints of pain which may supposedly arise from the anterior knee stemming from the unresurfaced patella. The evolution of more favorable anatomic femoral component designs which are very friendly to the patellofemoral articulation have resulted in lower patella resurfacing complications. The insertion of appropriately externally rotated tibial and femoral components, if not reducing anterior knee pain, have certainly minimised the risk of resurfaced patella complications. Also, with current surgical techniques of component insertion, the lateral release rate is extremely low, thus avoiding the possibility of avascularity developing in the resurfaced patella. This complication will almost completely be eliminated if the patella thickness is kept greater than 13 mm after patella resection. In my experience, patella complications from the resurfaced patella are extremely rare. Many unicompartmental knees require re-operation because of the development of progressive patellofemoral arthritis. Re-operation from anterior knee pain from progressive arthritis from the unresurfaced patella has given inferior results. Overall, meta-analysis data demonstrates decreased satisfaction, increased anterior knee pain and higher early revision rates in the unresurfaced group. National joint registries, especially the Australian registry support routine resurfacing; complications are low and outcomes are improved. Even though there exists controversy as to whether the patella should be resurfaced or not, there is an overwhelming consensus in the U.S. that there is little downfall nowadays with respect to resurfacing the patella

Orthopaedic surgeons vary in their attitude towards resurfacing of the patella in total knee arthroplasty. Few studies are available to assess outcome and patient preference. We evaluated post-operative anterior knee pain and knee preference in patients with bilateral knee replacements and unilateral patellar resurfacing. We reviewed 30 patients who had undergone bilateral knee replacement with patellar resurfacing on only one side. Follow-up was from five to 12 years and the patients were assessed using the Knee Society rating, an anterior knee pain rating and a satisfaction score. Patients were also asked specifically if they had a preference for either knee. Assessment was performed without knowing which patella had been resurfaced. Fourteen patients (47%) favoured the resurfaced knee, six (20%) the un-resurfaced knee and 10 (33%) had no particular preference. The overall prevalence of anterior knee pain was 50% in the un-resurfaced cases (six mild, six moderate, three severe) and 20% in the resurfaced knees (four mild, two moderate). No significant difference was found between knee scores. Three un-resurfaced patellae have been secondarily resurfaced. This study shows a significant preference for the resurfaced side (p< 0.01), with a higher prevalence of anterior knee pain in non-resurfaced patellae (p< 0.05)

Total knee arthroplasty (TKA) is recognised as an effective treatment for end-staged knee osteoarthritis. Up to 20% of these patients is unfortunately unsatisfied due to anterior knee pain from unknown origin (Bourne and al. 2010). The aim of this study is to compare knee 3D kinematics during gait of patients with anterior knee pain after TKA to an asymptomatic TKA group. Our hypothesis is that the painful TKA group would exhibit known kinematics characteristics during gait that increase patellofemoral (PF) stresses (i.e. dynamic flexion contracture, valgus alignment, valgus collapse or a quick internal tibial rotation movement) compared to the TKA asymptomatic group. Thirty-eight patients (45 knees) were recruited 12–24 months post-surgery done by one of three experienced orthopaedic surgeons (31 unilateral TKA and seven bilateral TKA, all using the same knee implant). Patients were divided according to their KOOS pain score (with a cut-off at 6/20 to be included in the painful group). The KOOS questionnaire was also used to assess activities of daily living, symptoms, sports and quality of life. A complete clinical and radiological work up was done on the painful group to exclude those with known explanation for pain (i.e. loosening, malrotation, infection and clinical instability). 3D knee kinematics during treadmill walking was captured and computed using the KneeKGTM system. For the painful and asymptomatic groups, demographic results show respectively: age of 64.4 ± 7.6 and 69.8 ± 8.3 years, BMI of 31.9 ± 5.0 and 28.1 ± 3.6 kg.m−2, speed of 1.8 ± 0.6 and 1.67 ± 0.5 miles/h., and 50% of women in each group. Only age and BMI showed to be statistically different between groups. The painful TKA group exhibited a valgus alignment when walking (at initial contact and during stance, p<0.001). No significant difference has been put forward for the flexion/extension and internal/external tibial rotation. Since a higher valgus alignment increases the Q angle, which lateralise the patella and increases PF stresses, results provide new insight on origin of symptoms. Conservative treatments for PF pain syndrome have shown to address the valgus alignment and improve symptoms, therefore the next step will be to assess the impact on pain level and alignment during gait of a personalised conservative management for the painful TKA group. Additionally, a study assessing the change in the radiological and dynamic alignment from pre to post surgery could bring valuable insight on the impact of surgical procedure on anterior knee pain

Introduction. High-volume image guided injections (HVIGI) followed by structured rehabilitation have been shown to be effective in various musculoskeletal conditions including Achilles tendinopathy and shoulder impingement syndrome. The aim was to explore the effect of a HVIGI in Hoffa's fat pad impingement, a common cause of anterior knee pain. Materials and Methods. 100 consecutive subjects who received a HVIGI followed by a standardised physiotherapy rehabilitation regime for Hoffa's fat pad impingement (diagnosed using clinical history, examination and magnetic resonance imaging) at one specialist MSK centre were sent a follow-up questionnaire. The questionnaire collected demographics, symptom length and the percentage improvement in symptoms following the HVIGI. All had received HVIGI consisting of 10ml of 0.5% Marcaine and 50mg of hydrocortisone followed by a structured rehabilitation programme with a focus on lower limb alignment control, flexibility, hip and knee strengthening in line with best practice. Data was analysed using SPSS version 20 at this interim stage; data collection is continuing. Results. The response rate at this point is currently 28%. Of the twenty-six subjects (9 female; 19 male; average age 37.8 ± 13.4) who completed the questionnaire 82% had had anterior knee pain symptoms for >6 months prior to receiving a HVIGI. The average percentage improvement in anterior knee pain was 45 ± 36.5% (range 0–100%). 48% of subjects reported a >6 month improvement in symptoms. No adverse effects were reported and no subject required anytime off work. Discussion. HVIGI with a structured rehabilitation programme should be considered in the short term management of Hoffa's fat pad impingement. Future research should be prospective, to improve the response rate, and consider longer term outcomes

Introduction: Traditionally adolescent anterior knee pain is considered to be a self limiting condition with no long term sequelae. However recently two publications have suggested the condition may be longer lasting. We wish to suggest that adolescent anterior knee pain may lead to patello femoral arthritis. Method: We have carried out a comparative study assessing the incidence of previous adolescent anterior knee in patients who underwent patello femoral replacement for isolated patello femoral arthritis and have compared them with a matched group of patients who had medial unicompartmental replacement for isolated medial compartment arthritis without patello femoral disease. All patients were sent a postal questionnaire enquiring about adolescent anterior knee pain, knee injury and patella instability. Results: Ninety-three PFR patients and 86 UKR patients replied. The incidence of adolescent AKF and patella instability was higher in the PFR.group. Conclusion: Adolescent anterior knee pain may not always be a benign self limiting condition since this as well as patella injury and instability was associated with subsequent isolated patello femoral arthritis

Whether or not to resurface the patella in total knee arthroplasty (TKA) remains controversial. Several methods of dealing with the patella exist: ALWAYS resurface; NEVER resurface; SOMETIMES resurface. There is good reason to consider selective patellar resurfacing. First, in an age of partial knee arthroplasty we have become more tuned in to analyzing patterns of arthritis. In TKA there is a high percentage of patients who do not have significant patellar cartilage wear or anterolateral knee pain. These patients may be candidates for leaving the patella unresurfaced in TKA. Arno et al found that 42% of patients had no significant patellar arthritis at the time of TKA. Roberts et al found that only 15% of patients should undergo patella resurfacing based on the presence of exposed bone on the patella; the other 85% could be considered suitable for leaving the patella unresurfaced. Second, despite a cumulative incidence of less than 5–10%, problems related to patellar resurfacing account for perhaps the most catastrophic complications encountered, with treatments that have limited success. These complications include fracture, avascular necrosis, extensor mechanism disruption, and anterior knee pain. Third, it is a fallacy to think that anterior knee pain (AKP) does not exist despite primary patellar resurfacing in TKA. Meftah (Ranawat) et al found that AKP persists in 30% of patients and new AKP develops in 10% of patients after TKA with patellar resurfacing. Barrack et al found that with patellar resurfacing the incidence of AKP is 28% in patients without preop AKP and 9% in those with preop AKP. They also found that without patellar resurfacing the incidence of new AKP was 14% and persistent AKP was 23%. Fourth, only roughly 44–64% of patients who undergo secondary patellar resurfacing for AKP after TKA with an unresurfaced patella actually get relief of their pain, suggesting that there is some other etiology of anterior knee pain. Residual component malalignment, boxy femoral components, PF overstuffing, referred pain or asymmetric resurfacing may explain ongoing pain. Finally, the data in well-designed studies show that selective patellar resurfacing can produce similar outcomes with and without resurfacing, particularly in those without significant patellar arthritis. In multiple studies, higher rates of secondary surgery occur when the patella is left unresurfaced in primary TKA, but this is for “pain” without clear etiology. On the other hand secondary surgery is rarely performed in TKA with patellar resurfacing for “pain” only, despite its high incidence. The quality of patellar cartilage at the time of primary TKA should be considered, as that may be the best indicator of whether a knee will do well without patellar resurfacing (that is, selective patellar resurfacing may be a better idea than never resurfacing the patella). While patellar resurfacing remains controversial in modern TKA, excellent outcomes are achievable with, and without, primary patellar resurfacing. Selectively leaving the patella unresurfaced when there is limited patellar arthritis may not only be highly effective, but it may also limit the incidence of secondary resurfacing that may occur with more substantial patellar arthritis while also minimizing the risk of some of the devastating complications that can occur due to patellar resurfacing in TKA

The results of a randomized controlled clinical trial of ninety patients comparing resurfacing to non-resurfacing of the patella in total knee arthroplasty (TKA) are reported with a minimum of ten-years of follow-up. Using a cruciate retaining hybrid TKA, the outcome measures included Knee Society Clinical Rating scores, functional testing (stair climb and flexion extension torques), patient satisfaction, anterior knee pain, and a patellofemoral specific questionnaire. The results indicated no difference between the groups in all categories. Results at two and ten years postoperatively are compared. This study represents the longest follow-up to date comparing resurfacing to nonresurfacing of the patella. Patellar resurfacing in TKA remains controversial. Purpose: To evaluate the results of resurfacing/non-resurfacing of the patella in a randomized controlled clinical trial at a minimum of ten-years of follow-up. One hundred knees (ninety patients) with osteoarthritis were enrolled in a prospective randomized controlled double-blinded trial using the same posterior cruciate retaining total knee replacement. Patients were randomized to resurfacing or nonresurfacing of the patella. Evaluations were performed preoperatively and yearly to a minimum ten years (range, 10.1–11.5 years) postoperatively. Disease specific (Knee Society Clinical Rating System), functional (stair climbing, knee flex-ion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intraoperative grading of the articular cartilage was performed. No patients were lost to follow-up; forty-six knees remained alive. Nine revisions (9/90-ten percent) were performed – 7/48 (fifteen percent) in the nonresurfaced and 2/42 (five percent) in the resurfaced group. Three knees in the nonresurfaced group were revised to a resurfaced patella for anterior knee pain. One resurfaced patella was complicated by AVN and fracture, requiring revision. No significant difference was found between the groups regarding revision rates, KSCR score, functional, satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome. This study represents the longest follow up to date of a randomized controlled clinical trial to examine patellar resurfacing in TKA. The results showed no significant difference between the groups for all outcome measures at a minimum of ten-years

The results of a randomized controlled clinical trial of ninety patients comparing resurfacing to non-resurfacing of the patella in total knee arthroplasty (TKA) are reported with a minimum of ten-years of follow-up. Using a cruciate retaining hybrid TKA, the outcome measures included Knee Society Clinical Rating scores, functional testing (stair climb and flexion extension torques), patient satisfaction, anterior knee pain, and a patellofemoral specific questionnaire. The results indicated no difference between the groups in all categories. Results at two and ten years postoperatively are compared. This study represents the longest follow-up to date comparing resurfacing to nonresurfacing of the patella. Patellar resurfacing in TKA remains controversial. Purpose: To evaluate the results of resurfacing/non-resurfacing of the patella in a randomized controlled clinical trial at a minimum of ten-years of follow-up. One hundred knees (ninety patients) with osteoarthritis were enrolled in a prospective randomized controlled double-blinded trial using the same posterior cruciate retaining total knee replacement. Patients were randomized to resurfacing or nonresurfacing of the patella. Evaluations were performed preoperatively and yearly to a minimum ten years (range, 10.1–11.5 years) postoperatively. Disease specific (Knee Society Clinical Rating System), functional (stair climbing, knee flexion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intraoperative grading of the articular cartilage was performed. No patients were lost to follow-up; forty-six knees remained alive. Nine revisions (9/90-ten percent) were performed – 7/48 (fifteen percent) in the nonresurfaced and 2/42 (five percent) in the resurfaced group. Three knees in the nonresurfaced group were revised to a resurfaced patella for anterior knee pain. One resurfaced patella was complicated by AVN and fracture, requiring revision. No significant difference was found between the groups regarding revision rates, KSCR score, functional, satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome. This study represents the longest follow up to date of a randomized controlled clinical trial to examine patellar resurfacing in TKA. The results showed no significant difference between the groups for all outcome measures at a minimum of ten-years

Introduction. Torsional malalignment syndrome (TMS) is a unique combination of rotational deformities in the lower limb, often leading to severe patellofemoral joint pain and disability. Surgical management of this condition usually consists of two osteotomies in each affected limb, with simultaneous correction of both femoral anteversion and external tibial torsion. However, we believe that a single supratubercular osteotomy followed by tibial derotation with the Taylor Spatial Frame (TSF) can be used to provide a significant improvement in both appearance and function. Materials and Methods. This is a retrospective case analysis in which we will be reviewing 16 osteotomies performed by one surgeon between 2006 and 2017. The study includes 11 patients with a mean age of 16.7 ± 0.8 years. Pre and post-operatively, patients were fully evaluated through history and physical examination, and CT rotational profiling. Statistical analyses were performed in order to determine whether or not any observed clinical or cosmetic improvements were statistically significant. Results. The results show significant improvements in scores reported on post-operative functional assessment, with mean Oxford Knee Score (OKS) increasing by 18.3 and mean Kujala Anterior Knee Pain Scale (AKPS) also increasing by 31.4. In addition to this, post-operative clinical assessment showed a reduced thigh-foot angle (TFA) in all cases, by a mean value of 31.9o. The angle of the transmalleolar axis (TMA) was successfully reduced in 14/16 cases, by a mean value of 8.6o. Statistical analysis showed all of these results to be statistically significant where p<0.05. Conclusions. The results show that supratubercular osteotomy, followed by gradual correction with TSF, can be used to provide a significant improvement in both appearance and function for patients suffering from TMS

Indications for Unicompartmental Knee Arthroplasty (UKA) vary between units. Some authors have suggested, and many surgeons believe, that medial UKA should only be performed in patients who localise their pain to the medial joint line. This is despite research showing a poor correlation between patient-reported location of pain and radiological or operative findings in osteoarthritis. The aim of this study is to determine the effect of patient-reported pre-operative pain location and functional outcome of UKA at one and five years. Pre-operative pain location data were collected for 406 knees (380 patients) undergoing Oxford medial UKA. Oxford Knee Score, American Knee Society Scores and Tegner activity scale were recorded preoperatively and at follow-up. 272/406 (67%) had pure medial pain, 25/406 (6%) had pure anterior knee pain and 109/406 (27%) had mixed or generalised pain. None had pure lateral pain. The primary outcome interval is one year; 132/406 patients had attained five years by the time of analysis and their five year data is presented. At one and five years, each group had improved significantly by each measure (mean δOKS 15.6 (SD 8.9) at year one, 16.3 (9.3) at year five). There was no difference between the groups, nor between patients with and without anterior knee pain or isolated medial pain. We have found no correlation between preoperative pain location and outcome. We conclude that localised medial pain should not be a prerequisite to UKA and that it may be performed in patients with generalised or anterior knee pain

Introduction: Anterior knee pain is a very common presenting symptom. Fat pad syndrome is an uncommon and a difficult condition to manage. The diagnosis is usually reached after a period of physiotherapy and investigation to rule out the more common aetiologies of anterior knee pain. Patients & Methods: All patients who underwent excision of the infrapatellar fat pad following a diagnosis of Fat pad syndrome are included. Each patient was evaluated to exclude patellofemoral problems and intraarticular pathologies as the cause of anterior knee pain. Each patient underwent MR imaging and all the excised specimens were sent for histological analysis. Results: The MR imaging provided with the provisional diagnosis in all patients. All the specimens were examined by a single senior histopathologist to correlate with the provisional diagnosis. The histology confirmed Hoffa’s syndrome in 5 patients and in the remaining 15 patients a spectrum of rare diagnoses as suspected by Magnetic Resonance imaging. The more notable conditions were two synovial sarcomas, three haemangiomas and a Giant cell tumour of the tendon sheath. All patients were treated successfully with complete excision. No recurrences were recorded at the end of 3 year follow-up and all patients were symptom free. Conclusion: The work up of a patient with suspected infrapatellar fat pad syndrome must include MR imaging and the exact underlying pathology should be confirmed with histological analysis of the excised fat pad as the rare causes include soft tissue malignancy

Introduction: Dysfunction of the patellofemoral mechanism presents as patella dislocation or subluxation with or without anterior knee pain. Causes are numerous and include ligamentous deficiency, muscular deficiency, anomlies of bony alignment and patellofemoral joint abnormalities. The 130 different procedures described to treat this condition reflect the multiple pathologies responsible. No single procedure has gained widespread acceptance. We present a surgical technique that attempts to correct as many of these deficiencies of the patellofemoral mechanism as possible. Method: The procedure consists of a lateral release, a vastus medialis tendon advancement and a tibial tubercle osteotomy. The ‘Q’ angle is corrected by medialisation of the tubercle, patella alta is corrected by a distalisation technique and joint reaction forces through the patellofemoral joint are reduced by placing the tibial tuberosity in a more anterior position. 100 patients who have undergone this procedure have been identified. 81 percent initially presented with patella subluxation or dislocation. The remainder complained of anterior knee pain with evidence of abnormal patella tracking on examination. 52 percent of our patients had undergone at least one previous patellofemoral realignment procedure which had failed. 43 percent of the patients had generalised ligamentous laxity. Results: The mean follow-up was 2.6 years from the index operation. 81 percent of the patients stated the operation had improved or abolished their symptoms. Generalised ligamentous laxity was present in the remaining 19 percent and seemed to correlate with a poor outcome. 66 percent of patients stated they were satisfied with the outcome of the surgery. Two patients developed recurrent subluxation after surgery and one of these has undergone a revision distal realignment procedure. Using the functional category described by Crosby and Insall for patellofemoral symptoms 66 percent had a good-to-excellent outcome, 23 percent had a fair outcome and 10 percent of the patients stated they were worse following the procedure with increased anterior knee pain. 100 percent of these patients had grade 3 or 4 cartilage defects on retropatella surface. 57% of patients returned to sporting activity. 14% of the remainder had not returned to sporting activity because of persisting symptoms in the knee. 57 percent of patients had lost a mean 12.5 degrees of flexion of the knee at follow-up [range 5–30]. 5 percent of patients developed minor complications following surgery. No radiological deterioration was seen in any patients although coexistent patellofemoral osteoarthritis was seen in 25 percent of patients. There was no loss of fixation in any of the patients. Discussion: A multifaceted approach to the complex problem of patellofemoral dysfunction appears to achieve satisfactory functional results in patients even when previous surgical realignment has failed. The procedure appears to be associated with low morbidity although a loss of flexion of the knee is to be expected. Generalised ligamentous laxity and cartilage defects on the retropatella surface appear to be associated with poor results and anterior knee pain in the absence of instability may be a cause for persisting symptoms

Mechanical abnormalities of the patellofemoral joint are among the many causes that have been suggested for adolescent knee pain. This study seeks to identify these factors. Measurements of joint mobility and lower limb morphology were made on 446 pupils at a comprehensive school, 136 of whom had suffered knee pain in the previous year. The pupils with symptoms enjoyed sporting activities significantly more than their symptom-free contemporaries. Joint mobility, the Q-angle, genu valgum and anteversion of the femoral neck were not significantly different between those pupils with and those without anterior knee pain. Data on lower limb morphology of normal adolescents are presented. Examination of 52 hospital outpatients aged 13 to 36 years with anterior knee pain produced results comparable with those for the pupils. It is concluded that chronic overloading, rather than faulty mechanics, is the dominant factor in the genesis of anterior knee pain in adolescent patients

Introduction. Management of the patellofemoral surface in total knee arthroplasty (TKA) remains a topic of debate. Incidence of anterior knee pain and incidence of repeat operation have been the focus of several recent meta-analyses, however there is little recent data regarding patients” subjective ability to kneel effectively after TKA. The purpose of this study was to compare patient reported outcomes, including reported ability to kneel, after total knee arthroplasty with and without patellar resurfacing. Methods. Retrospective chart review of 84 consecutive patients who underwent primary TKA with patella resurfacing (56 knees) or without patella resurfacing (28 knees) having a minimum of 2.5 year follow up was performed. Oxford knee scores (OKS), visual analog pain scores (VAS), and questionnaires regarding ability to kneel were evaluated from both groups. Inability to kneel was defined as patients reporting inability or extreme difficulty with kneeling. Shapiro-Wilk test was used to determine normality of data. Mann Whitney U test was used to compare the OKS and VAS between groups. Chi square test was used to compare kneeling ability between groups. Statistical analysis was performed with SPSS version 23 (IBM, Aramonk, NY). Results. The 84 patients included 26 males and 58 females with average age 66.5 (range 46–91). Average follow up was 51 months (range 30–85). There was no significant difference in the percentage of female patients (64% vs 79%), age (67.8 vs 63.8), or reoperation rate (4% vs 7%) between the resurfaced and non-resurfaced groups. There was significantly longer follow up in the non-resurfaced group (57 vs 48 months). There was no statistically significant difference between the resurfacing and non-resurfacing group in terms of OKS (39 vs 38) or VAS (2.5 vs 3.0). However, those patients who did not have their patellofemoral joint resurfaced were more likely to report ability to kneel when compared to the resurfacing group (64% vs 39%, p=0.035). Kneeling ability was not correlated with duration of follow up, patient age or VAS. Kneeling ability was higher in female patients (57%) than males (27%), p=0.017. Discussion. There is concern for increased anterior knee pain and reoperation in patients whose patellae are not resurfaced. However, their failure to imnprove after revision to a resurfaced patella has left some room for depate as to whether or not the lack of resurfacing is the cause of their problems. This study did not show any increase in knee pain or reoperation between groups. There was an increased subjective ability to kneel in paients whose patellae were not resurfaced. This may have implications for the subset of paeitnts whose work or hobbies may require kneeling. There have been previous reports that subjective ability to kneel and actual ability may differ, and also that kneeling can be taught by a therapist. Our data also shows that female gender had a higher reported rate of kneeling

The purpose of this study was to evaluate the role of patellar resurfacing in total knee replacement surgery. We reviewed 48 patients who had undergone bilateral knee replacement with patellar resurfacing on only one side. Follow-up was from 18 months to 9.5 years and the patients were assessed using the Knee Society rating, a clinical anterior knee pain score and BOA patient satisfaction score. Patients were also asked specifically if they had a preference for either knee. Assessment was performed without knowing which patella had been resurfaced. 52.1% of patients favoured the resurfaced knee, 8% the unresurfaced knee and 39.9% had no particular preference. The overall prevalence of anterior knee pain was 8.3% in the resurfaced cases (3 mild, 1 moderate) and 27.1% in the unresurfaced knees (8 mild, 3 moderate, 2 severe). No significant difference was found between knee scores. This study shows a significantly higher rate of anterior knee pain in unresurfaced patellae and preference for the resurfaced side

Introduction: Existing data in the literature is supporting either patellar retention or patellar resurfacing during primary TKA. There is no clear answer for the question in which cases the patella should be retained or resurfaced during primary TKA. Materials and Methods: In this prospective study 2 groups of patients with a mean follow up of 34 months after TKA were compared. 83 patients (98 TKA) were implanted with a TKA with patellar retention (group 1) while 93 TKA (86 patients) were done including a patellar resurfacing (group 2). The patients were randomized according to the year of birth. The NexGen® MBK and the LPS were implanted. A dome shaped patellar prosthesis with 3 pegs was used for patellar resurfacing. Clinical Outcomes were based on the knee society score parameters, anterior knee pain, patient satisfaction, feeling of instability, step test while component position and limb alignment were measured by standard radiographs. Results: No statistical differences between both groups with regard to post-operative anterior knee pain and knee society score were found. We found no pre-operative predictor factors for the development of post-operative anterior knee pain for each group and both together. Patellar maltracking was worse in group 1 than in the resurfaced group (3 cases with patellar subluxation in group 1 versus 2 cases in group 2). Conclusion: According to the not significant differences for the clinical outcomes between group 1 and 2 we routinely retain the patella. Patellar resurfacing is done only in selective cases

Introduction: Patellar management and related complications remain a major concern in total knee arthroplasty. Multiple problems can ensue in both resurfaced (fracture, loosening) and non-resurfaced patellae (pain). Objective: We aim to evaluate the impact of secondary patellar resurfacing in patients with patellar related anterior knee pain having undergone a mobile bearing primary total knee arthroplasty without resurfacing. Materials and methods: 2950 primary LCS mobile bearing total knee arthroplasties without patellar resurfacing were carried out between March 1992 and March 22003 by the senior author. Twelve patients underwent secondary patellar resurfacing for patellar related anterior knee pain. There were equal numbers male and female with a mean age of 72.1 years. There was a mean time of 27.9 months to secondary resurfacing procedure. We evaluated both clinical and radiological outcomes of this procedure. Results: 0.4% patients required a secondary procedure. Only 3 had an unequivocal improvement in their symptoms. No morbidity was noted from the procedure. Conclusions: The success rate of secondary patellar resurfacing is poor and we feel if this is to be offered to the patient for ongoing patellar related anterior knee pain that they be counseled carefully

Patients with spastic diplegia who walk with a crouched posture often suffer from anterior knee pain, thought to be due to cephalad displacement of the patella. Ambulation with flexed knees elongates the patellar tendon, which leads to development of patella alta. Our study of 57 patients with spastic diplegia aimed to determine the severity of patella alta and to investigate its correlation with spasticity and muscle imbalance at the level of the knee. The ages of the 31 male and 26 female patients ranged from 3 months to 16 years. They were divided into two groups, one with spasticity of the hamstrings and the other with combined spasticity of the quadriceps and hamstrings. Clinical evaluation documented anterior knee pain, walking capacity, fixed deformities, hamstrings and rectus femoris shortening, and patellar mobility. Lateral radiographs were taken to measure the length of the patella and the patellar tendon. We used the method described by Insall and Salvati to calculate the patellar ratio. The clinical findings were examined for correlations with the severity of patella alta. We found that the group of patients with quadriceps and hamstring spasticity had a higher rate of patellar displacement but less frequent anterior knee pain than the group of patients with hamstring spasticity alone

Aims: We studied the outcome of a progressive correction of the rotation malalignment syndrome with combined supracondylar and proximal tibial osteotomy. We evaluated the associated anterior knee pain in most patients due to patellar maltracking. Methods: Between 1991 and 2002, 56 combined femoral and tibial osteotomies were performed in 37 patients (mean age 18 years). Ilizarov method was used for correction of the idiopathic anteversion with combined tibial external rotation. The þxator was kept in place for an average of 4.4 months and mean follow up was 3 years. Results: In more than 90% of the patients with preoperative anterior knee pain, the symptoms diminished or disappeared. All alignments were corrected adequately. A temporary neuropraxia of the peroneal nerve was seen with acute derotation of the tibia. This technique was abandoned. Four patients were not satisþed for cosmetic reasons, due to the multiple scars from the pins especially on the upper thigh. Postoperative problems were uncommon. There was one undisplaced femoral fracture after removal of the frame and one overcorrection was seen, that could be treated with a new osteotomy with progressive external derotation. Conclusions: The progressive derotation technique using the Ilizarov method allows a reliable correction of a rotational malalignment syndrome with a concomitant improvement of anterior knee pain

Introduction and Aims: Problem: Patellar resurfacing in TKA remains controversial. Purpose: To evaluate the results of resurfacing/non-resurfacing of the patella in a randomised controlled clinical trial at a minimum of 10 years of follow-up. Method: One hundred knees (90 patients) with osteoarthritis were enrolled in a prospective randomised controlled double-blinded trial using the same posterior cruciate retaining total knee replacement. Patients were randomised to resurfacing or non-resurfacing of the patella. Evaluations were performed pre-operatively and yearly to a minimum of 10 years (range 10.1–11.5 years) postoperatively. Disease-specific (Knee Society Clinical Rating System), functional (stair climbing, knee flexion/extension torques, patellar examination) outcomes were measured. Patient satisfaction, anterior knee pain, and patellofemoral questionnaires were completed. Intra-operative grading of the articular cartilage was performed. Results: No patients were lost to follow-up; 46 knees remained alive. Nine revisions (9/90–10%) were performed – 7/48 (15%) in the non-resurfaced and 2/42 (5%) in the resurfaced group. Three knees in the non-resurfaced group were revised to a resurfaced patella for anterior knee pain. One resurfaced patella was complicated by AVN and fracture, requiring revision. No significant difference was found between the groups regarding revision rates, KSCR score, functional, satisfaction, anterior knee pain, patellofemoral, and radiographic outcomes. Intraoperative cartilage quality was not a predictor of outcome. Conclusions: This study represents the longest follow-up to date of a randomised controlled clinical trial to examine patellar resurfacing in TKA. The results showed no significant difference between the groups for all outcome measures at a minimum of 10 years