Objectives. It has been hypothesized that patellofemoral pain, a common knee condition in adolescents and young adults, may be a precursor of degenerative joint changes and may ultimately lead to patellofemoral osteoarthritis. Since both conditions share several mechanical disease characteristics, such as altered contact area between the femur and patella and increased joint stress, we investigated whether these conditions share similar and different shape characteristics of the patella compared with normal controls. Methods. This cross-sectional study compared three different study populations: 32 patellofemoral pain subjects (mean age, 32 years (22 to 45); 72% female); 56 isolated radiological patellofemoral osteoarthritis subjects (mean age, 54 years (44 to 58); 89% female); and 80 healthy control subjects (mean age, 52 years (44 to 58); 74% female). Measurements included questionnaires, and lateral and skyline radiographs of the knee. Two separate 30-point 2D statistical shape models of the patella were created from the lateral and skyline radiographs. A general linear model was used to test for differences in standardized shape modes (a specific shape variant of the patella) between patellofemoral osteoarthritis, patellofemoral pain, and controls, using Bonferroni correction and adjustment for body mass index and gender. Results. Five shape modes showed statistically significant differences between groups: skyline modes 1 (p < 0.001), 8 (p = 0.004), and 10 (p < 0.001); and lateral modes 5 (p = 0.002) and 7 (p = 0.002). Skyline mode 8 and lateral mode 5 were similar for patellofemoral osteoarthritis and patellofemoral pain populations, while being statistically significant different from the control group. Conclusion. Our results indicate that patellofemoral pain and patellofemoral osteoarthritis share similar shape characteristics, which are different from control subjects. These findings support the proposed continuum disease model of patellofemoral pain predisposing to the development of patellofemoral osteoarthritis. Cite this article: J. F. A. Eijkenboom, J. H. Waarsing, E. H. G. Oei, S. M. A. Bierma-Zeinstra, M. van Middelkoop. Is patellofemoral pain a precursor to osteoarthritis? Patellofemoral osteoarthritis and patellofemoral pain patients share aberrant patellar shape compared with healthy controls. Bone Joint Res 2018;7:541–547. DOI: 10.1302/2046-3758.79.BJR-2018-0112.R1

An increased tibial tubercle–trochlear groove (TT-TG) distance is related to patellar maltracking and instability. Tibial tubercle transfer is a common treatment option for these patients with good short-term results, although the results can deteriorate over time owing to the progression of osteoarthritis. We present a ten-year follow-up study of a self-centring tibial tubercle osteotomy in 60 knees, 30 with maltracking and 30 with patellar instability. Inclusion criteria were a TT-TG ≥ 15 mm and symptoms for > one year. One patient (one knee) was lost to follow-up and one required total knee arthroplasty because of progressive osteoarthritis. Further patellar dislocations occurred in three knees, all in the instability group, one of which required further surgery. The mean visual analogue scores for pain, and Lysholm and Kujala scores improved significantly and were maintained at the final follow-up (repeated measures, p = 0.000, intergroup differences p = 0.449). Signs of maltracking were found in only a minority of patients, with no difference between groups (p > 0.05). An increase in patellofemoral osteoarthritis was seen in 16 knees (31%) with a maximum of grade 2 on the Kellgren–Lawrence scale. The mean increase in grades was 0.31 (0 to 2) and 0.41 (0 to 2) in the maltracking and instability groups respectively (p = 0.2285). This self-centring tibial tubercle osteotomy provides good results at ten years’ follow-up without inducing progressive osteoarthritis. Cite this article: Bone Joint J 2015;97-B:329–36

An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients.

In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score.

Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation.

If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella.

We investigated the clinical and radiological outcome of trochleaplasty for recurrent patellar dislocation in association with trochlear dysplasia in 38 consecutive patients (45 knees) with a mean follow-up of 8.3 years (4 to 14). None had recurrence of dislocation after trochleaplasty. Post-operatively, patellofemoral pain, present pre-operatively in only 35 knees, became worse in 15 (33.4%), remained unchanged in four (8.8%) and improved in 22 (49%). Four knees which had no pain pre-operatively (8.8%) continued to have no pain. A total of 33 knees were available for radiological assessment. Post-operatively, all but two knees (93.9%) had correction of trochlear dysplasia radiologically but degenerative changes of the patellofemoral joint developed in 30% (10) of the knees. We conclude that recurrent patellar dislocation associated with trochlear dysplasia can be treated successfully by trochleaplasty, but the impact on patellofemoral pain and the development of patellofemoral osteoarthritis is less predictable. Overall, subjective patient satisfaction with restored patellofemoral stability after trochleaplasty appeared to outweigh its possible sequelae

Objectives. Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational simulation to investigate the influence of femoral malrotation on contact stresses on the polyethylene (PE) insert and on the patellar button as well as on the forces on the collateral ligaments. Materials and Methods. Validated finite element (FE) models, for internal and external malrotations from 0° to 10° with regard to the neutral position, were developed to evaluate the effect of malrotation on the femoral component in TKA. Femoral malrotation in TKA on the knee joint was simulated in walking stance-phase gait and squat loading conditions. Results. Contact stress on the medial side of the PE insert increased with internal femoral malrotation and decreased with external femoral malrotation in both stance-phase gait and squat loading conditions. There was an opposite trend in the lateral side of the PE insert case. Contact stress on the patellar button increased with internal femoral malrotation and decreased with external femoral malrotation in both stance-phase gait and squat loading conditions. In particular, contact stress on the patellar button increased by 98% with internal malrotation of 10° in the squat loading condition. The force on the medial collateral ligament (MCL) and the lateral collateral ligament (LCL) increased with internal and external femoral malrotations, respectively. Conclusions. These findings provide support for orthopaedic surgeons to determine a more accurate femoral component alignment in order to reduce post-operative PE problems. Cite this article: K-T. Kang, Y-G. Koh, J. Son, O-R. Kwon, C. Baek, S. H. Jung, K. K. Park. Measuring the effect of femoral malrotation on knee joint biomechanics for total knee arthroplasty using computational simulation. Bone Joint Res 2016;5:552–559. DOI: 10.1302/2046-3758.511.BJR-2016-0107.R1

Isolated patellofemoral arthritis is a common condition and there are varying opinions on the most effective treatments. Non-operative and operative treatments have failed to demonstrate effective long-term treatment for those in an advanced stage of the condition. Newer designs and increased technology in patellofemoral replacement (PFR) have produced more consistent outcomes. This has led to a renewed enthusiasm for this procedure. Newer PFR prostheses have addressed the patellar maltracking issues plaguing some of the older designs. Short-term results with contemporary prostheses and new technology are described here. . Cite this article: Bone Joint J 2013;95-B, Supple A:124–8

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.

Aims

This study aimed to evaluate if total knee arthroplasty (TKA) femoral components aligned in either mechanical alignment (MA) or kinematic alignment (KA) are more biomimetic concerning trochlear sulcus orientation and restoration of trochlear height.

Aims

The transepicondylar axis is a well-established reference for the determination of femoral component rotation in total knee arthroplasty (TKA). However, when severe bone loss is present in the femoral condyles, rotational alignment can be more complicated. There is a lack of validated landmarks in the supracondylar region of the distal femur. Therefore, the aim of this study was to analyze the correlation between the surgical transepicondylar axis (sTEA) and the suggested dorsal cortex line (DCL) in the coronal plane and the inter- and intraobserver reliability of its CT scan measurement.

Aims

Distal femoral osteotomies (DFOs) are commonly used for the correction of valgus deformities and lateral compartment osteoarthritis. However, the impact of a DFO on subsequent total knee arthroplasty (TKA) function remains a subject of debate. Therefore, the purpose of this study was to determine the effect of a unilateral DFO on subsequent TKA function in patients with bilateral TKAs, using the contralateral knee as a self-matched control group.

Aims

This study aims to identify the top unanswered research priorities in the field of knee surgery using consensus-based methodology.

Aims

The aims of this study were: 1) to describe extended restricted kinematic alignment (E-rKA), a novel alignment strategy during robotic-assisted total knee arthroplasty (RA-TKA); 2) to compare residual medial compartment tightness following virtual surgical planning during RA-TKA using mechanical alignment (MA) and E-rKA, in the same set of osteoarthritic varus knees; 3) to assess the requirement of soft-tissue releases during RA-TKA using E-rKA; and 4) to compare the accuracy of surgical plan execution between knees managed with adjustments in component positioning alone, and those which require additional soft-tissue releases.

Aims

The primary aim of this study was to compare the migration of the femoral and tibial components of the cementless rotating platform Attune and Low Contact Stress (LCS) total knee arthroplasty (TKA) designs, two years postoperatively, using radiostereometric analysis (RSA) in order to assess the risk of the development of aseptic loosening. A secondary aim was to compare clinical and patient-reported outcome measures (PROMs) between the designs.

Aims

This study aimed to describe the use of revision knee arthroplasty in Australia and examine changes in lifetime risk over a decade.

Aims

Despite new technologies for total knee arthroplasty (TKA), approximately 20% of patients are dissatisfied. A major reason for dissatisfaction and revision surgery after TKA is persistent pain. The radiological grade of osteoarthritis (OA) preoperatively has been investigated as a predictor of the outcome after TKA, with conflicting results. The aim of this study was to determine if there is a difference in the intensity of pain 12 months after TKA in relation to the preoperative radiological grade of OA alone, and the combination of the intensity of preoperative pain and radiological grade of OA.

Aims

The mid-term results of kinematic alignment (KA) for total knee arthroplasty (TKA) using image derived instrumentation (IDI) have not been reported in detail, and questions remain regarding ligamentous stability and revisions. This paper aims to address the following: 1) what is the distribution of alignment of KA TKAs using IDI; 2) is a TKA alignment category associated with increased risk of failure or poor patient outcomes; 3) does extending limb alignment lead to changes in soft-tissue laxity; and 4) what is the five-year survivorship and outcomes of KA TKA using IDI?

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

In a two-centre study, 164 patients with unilateral instability of the anterior cruciate ligament were prospectively randomised to arthroscopic reconstruction with either a patellar tendon graft using interference screw fixation or a quadruple semitendinosus graft using an endobutton fixation technique. The same postoperative rehabilitation protocol was used for all patients and follow-up at a median of 31 months (24 to 59) was carried out by independent observers. Four patients (2%) were lost to follow-up. No significant differences were found between the groups regarding the Stryker laxity test, one-leg hop test, Tegner activity level, Lysholm score, patellofemoral pain score, International Knee Documentation Committee (IKDC) score or visual analogue scale, reflecting patient satisfaction and knee function. Slightly decreased extension, compared with the non-operated side, was found in the patellar tendon group (p < 0.05). Patients with associated meniscal injuries had lower IKDC, visual analogue (p < 0.01) and Lysholm scores (p < 0.05) than those without such injuries. Patients in whom reconstruction had been carried out less than five months after the injury had better final IKDC scores than the more chronic cases (p < 0.05). We conclude that patellar tendon and quadruple semitendinous tendon grafts have similar outcomes in the medium term. Associated meniscal pathology significantly affects the final outcome and early reconstruction seems to be beneficial

Aims

Unicompartmental knee arthroplasty (UKA) is a bone-preserving treatment option for osteoarthritis localized to a single compartment in the knee. The success of the procedure is sensitive to patient selection and alignment errors. Robotic arm-assisted UKA provides technological assistance to intraoperative bony resection accuracy, which is thought to improve ligament balancing. This paper presents the five-year outcomes of a comparison between manual and robotically assisted UKAs.

Limb alignment in total knee arthroplasty (TKA) influences periarticular soft-tissue tension, biomechanics through knee flexion, and implant survival. Despite this, there is no uniform consensus on the optimal alignment technique for TKA. Neutral mechanical alignment facilitates knee flexion and symmetrical component wear but forces the limb into an unnatural position that alters native knee kinematics through the arc of knee flexion. Kinematic alignment aims to restore native limb alignment, but the safe ranges with this technique remain uncertain and the effects of this alignment technique on component survivorship remain unknown. Anatomical alignment aims to restore predisease limb alignment and knee geometry, but existing studies using this technique are based on cadaveric specimens or clinical trials with limited follow-up times. Functional alignment aims to restore the native plane and obliquity of the joint by manipulating implant positioning while limiting soft tissue releases, but the results of high-quality studies with long-term outcomes are still awaited. The drawbacks of existing studies on alignment include the use of surgical techniques with limited accuracy and reproducibility of achieving the planned alignment, poor correlation of intraoperative data to long-term functional outcomes and implant survivorship, and a paucity of studies on the safe ranges of limb alignment. Further studies on alignment in TKA should use surgical adjuncts (e.g. robotic technology) to help execute the planned alignment with improved accuracy, include intraoperative assessments of knee biomechanics and periarticular soft-tissue tension, and correlate alignment to long-term functional outcomes and survivorship.