Do patients with a failed metal-on-metal hip implant with a pseudotumor present differences in their peripheral blood lymphocyte subpopulations?

BACKGROUND: Early adverse tissue reactions around metal-on-metal (MoM) hip replacements, especially pseudotumors, are a major concern. Because the causes and pathomechanisms of these pseudotumors remain largely unknown, clinical monitoring of patients with MoM bearings is challenging. QUESTIONS/PURPOSES: The purpose of this study was to compare the lymphocyte subpopulations in peripheral blood from patients with a failed MoM hip implant with and without a pseudotumor and patients with a well-functioning MoM hip implant without a pseudotumor. Potential differences in the systemic immune response are expected to reflect local differences in the periprosthetic tissues. METHODS: Consenting patients who underwent a revision of a failed MoM hip implant at The Ottawa Hospital (TOH) from 2011 to 2014, or presented with a well-functioning MoM hip implant for a postoperative clinical followup at TOH from 2012 to 2013, were recruited for this study, unless they met any of the exclusion criteria (including diagnosed conditions that can affect peripheral blood lymphocyte subpopulations). Patients with a failed implant were divided into two groups: those with a pseudotumor (two hip resurfacings and five total hip arthroplasties [THAs]) and those without a pseudotumor (10 hip resurfacings and two THAs). Patients with a well-functioning MoM hip implant (nine resurfacings and three THAs) at 5 or more years postimplantation and who did not have a pseudotumor as demonstrated sonographically served as the control group. Peripheral blood subpopulations of T cells (specifically T helper [Th] and cytotoxic T [Tc]), B cells, natural killer (NK) cells, memory T and B cells as well as type 1 (expressing interferon-γ) and type 2 (expressing interleukin-4) Th and Tc cells were analyzed by flow cytometry after immunostaining. Serum concentrations of cobalt and chromium were measured by inductively coupled plasma-mass spectrometry. RESULTS: The mean percentages of total memory T cells and, specifically, memory Th and memory Tc cells were lower in patients with a failed MoM hip implant with a pseudotumor than in both patients with a failed implant without a pseudotumor and patients with a well-functioning implant without a pseudotumor (memory Th cells: 29% ± 5% [means ± SD] versus 55% ± 17%, d = 1.8, 95% confidence interval [CI] [1.2, 2.5] and versus 48% ± 14%, d = 1.6, 95% CI [1.0, 2.2], respectively; memory Tc cells: 18% ± 5% versus 45% ± 14%, d = 2.3, 95% CI [1.5, 3.1] and versus 41% ± 12%, d = 2.3, 95% CI [1.5, 3.1], respectively; p < 0.001 in all cases). The mean percentage of memory B cells was also lower in patients with a failed MoM hip implant with a pseudotumor than in patients with a well-functioning implant without a pseudotumor (12% ± 8% versus 29% ± 16%, d = 1.3, 95% CI [0.7, 1.8], p = 0.025). In addition, patients with a failed MoM hip implant with a pseudotumor had overall lower percentages of type 1 Th cells than both patients with a failed implant without a pseudotumor and patients with a well-functioning implant without a pseudotumor (5.5% [4.9%-5.8%] [median with interquartile range] versus 8.7% [6.5%-10.2%], d = 1.4, 95% CI [0.8, 2.0] and versus 9.6% [6.4%-11.1%], d = 1.6, 95% CI [1.0, 2.2], respectively; p ≤ 0.010 in both cases). Finally, serum cobalt concentrations in patients with a failed MoM hip implant with a pseudotumor were overall higher than those in patients with a well-functioning implant without a pseudotumor (5.8 µg/L [2.9-17.0 µg/L] versus 0.9 µg/L [0.6-1.3 µg/L], d = 2.2, 95% CI [1.4, 2.9], p < 0.001). CONCLUSIONS: Overall, results suggest the presence of a type IV hypersensitivity reaction, with a predominance of type 1 Th cells, in patients with a failed MoM hip implant with a pseudotumor. CLINICAL RELEVANCE: The lower percentages of memory T cells (specifically Th and Tc) as well as type 1 Th cells in peripheral blood of patients with a failed MoM hip implant with a pseudotumor could potentially become diagnostic biomarkers for the detection of pseudotumors. Although implant design (hip resurfacing or THA) did not seem to affect the results, as suggested by the scatter of the data with respect to this parameter, future studies with additional patients could include the analysis of implant design in addition to correlations with histological analyses of specific Th subsets in periprosthetic tissues.

Medial patellofemoral ligament reconstruction with bioactive synthetic ligament is an option. A 3-year follow-up study.

PURPOSE: The purpose of this study was to evaluate mid-term follow-up results of medial patellofemoral ligament (MPFL) reconstruction using a bioactive synthetic ligament in the treatment of objective patellofemoral (PF) instability. METHODS: Sixteen patients (18 knees) presenting with objective PF instability underwent a MPFL reconstruction, isolated or associated with other surgical procedures for PF stabilization. All patients were clinically evaluated at a minimum follow-up of 3 years. Kujala, subjective IKDC and KOOS scores were used to assess clinical outcome. Pre-operative and post-operative pain was quantified with VAS scale and the overall satisfaction graded according to Insall and Crosby. Although none of the patients in this series were involved in high-level sports activity because of patellofemoral instability, activity level pre-operatively and at follow-up were evaluated according to Tegner scale. RESULTS: No recurrence of dislocation was observed in this series. The overall satisfaction rate was 88.8%. Kujala score improved significantly from 57±8.4 to 84.3±10.2 points (p<.01). Both subjective IKDC (42.4±7.13 to 70.1±3.9) and KOOS (62.7±4.34 to 82.8±8.8) significantly improved from pre-operative evaluation (p<.01). VAS decreased from a mean pre-operative value of 2.5±1.6 to 1.4±1.5 at 3 years follow-up. Only one patient required revision debridement surgery for persistent medial epicondylar pain. CONCLUSIONS: Isolated or associated MPFL reconstruction with bioactive synthetic ligament is a valid option in surgical treatment of objective PF instability, with results at mid-term follow-up comparable to autologous graft, thus minimizing donor-site morbidity and associated complications. LEVEL OF EVIDENCE: IV.

Proximal femoral arthroplasty in patients undergoing revision hip arthroplasty.

Bone loss represents one of the greatest challenges in revision joint surgery. A retrospective review was conducted of both radiographic and clinical outcomes of eleven patients who underwent revision arthroplasty using a long extensively porous coated cylindrical femoral component. All patients' femurs presented with severe proximal femoral bone loss (Paprosky class IIIB and IV). With a mean follow-up of 8 years (2 to 14) we report no femoral revisions and one acetabular revision to a constrained cup secondary to instability. All patients were clinically and radiographically stable. We did not observe any issue with proximal stress shielding or component loosening. The article reports that in patients with severe proximal femoral bone loss, extensively porous-coated non-modular stems are a viable option offering stable and predictable outcomes.

Congenital absence of the cruciate ligaments.

Congenital absence of the cruciate ligaments is a rare condition with a prevalence of 0.017 per 1,000 live births. The most important finding of this study was the presence of a posterior menisco-femoral ligament of Wrisberg with cruciate ligaments agenesia and the hypothesis advanced about the development of the ligamentous structures of the knee. Reviewing the literature, we assume that the congenital anomaly that causes the anatomical defect expresses itself around the 7th to 8th post-ovulatory week. Literature teaches us that the need for a knee replacement seems to be inevitable before or after and during the life of a patient without cruciate ligaments.

Natural history of lateral femoral cutaneous nerve neuropraxia after anterior approach total hip arthroplasty.

AIM:: The aim of this study was to examine the natural history of lateral femoral cutaneous nerve (LFCN) neuropraxia in a previously reported cohort of individuals after direct anterior approach (DAA). METHODS:: 99 patients (107 hips) with LFCN neuropraxia were identified, out of which 82 patients (87 hips) (83.1%) completed functional outcomes questionnaires at mean follow-up of 5.5 years (4.4-6.9 years). 5 patients were excluded from the study due to intra-articular source of pain and/or revision surgery. The total sample was composed of 77 patients (31 total hip replacements and 51 hip resurfacings) and functional outcomes scores were obtained for all patients. RESULTS:: At average 5.46-year follow-up, 55 patients (60 hips 73%) still reported symptoms of LFCN neuropraxia but their Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were not inferior to those who had resolution for pain, function and stiffness: p values of 0.716, 0.171, and 0.238, respectively. The mean score on visual analogue scale decreased from 2.32 (SD 2.11) to 1.76 (SD 1.99). 1 patient (1.2%) reported his activities were limited by his symptoms. CONCLUSION:: Although the majority of patients still report symptoms related to LFCN neuropraxia, symptoms do improve over time and there are no functional limitations. Even if LFCN neuropraxia following DAA does not lead to functional limitations, all patients should be made aware in order to alleviate any long-term functional concerns.

Is there still a role for threaded acetabular cups?

INTRODUCTION:: Total hip arthroplasty (THA) is 1 of the most common procedures in orthopaedic surgery. Different options and implants are currently available. Uncemented hip cups need primary stability for bone ingrowth, the use of screws is required when the desired stability is not achieved. Another option is the use of a hemispherical threaded cup with enhanced primary stability. The purpose of our study was to compare the results of a 3rd-generation threaded cup versus a press-fit cup with a long track record. MATERIALS AND METHODS:: A consecutive series of 300 THAs performed by 2 surgeons was retrospectively reviewed, 150 press-fit cups and 150 screwed cups. Minimum follow-up 27 months; maximum 78 months (mean 52.5 months). The primary endpoint was a stable and painless THA, secondary endpoints included Hip disability and Osteoarthritis Outcome Score, Junior and radiographic evaluation. RESULTS:: Preliminary results showed no statistically significant differences between the 2 groups for all the evaluated parameters, the number of early mechanical loosening was higher for press-fit cups, but this value was not statistically significant. At a mean follow-up of 52.5 months 1 cup revision (0.3%) was seen in the screwed cup group and 2 (0.6%) in the press-fit cup; these results were not statistically significant. DISCUSSION AND CONCLUSION:: The main concern for screwed cups is the greater bone loss and possible removal difficulties during revision surgery. This study has some limitations, in particular regarding follow-up, but is still ongoing. Our results showed no difference between the 2 systems.

Hip Dysplasia in the Young Adult.

Hip dysplasia is a leading precursor of osteoarthritis and is seen in 20% to 40% of patients with osteoarthritis of the hip. An increase in mechanical stress on the cartilage matrix with failure of the acetabular labrum represents the major pathomechanism of degeneration. Because the prevalence of associated femoral deformities is high (>50%), the structural anatomy of the dysplastic hip must be assessed in multiple planes using radiographs and, if needed, advanced imaging modalities. Acetabular osteotomy (periacetabular and/or rotational) is the most commonly used procedure for the treatment of the majority of dysplastic hips in adults. Modern total hip replacement remains an excellent option for the more arthritic joints. Difficulties can arise from anatomical abnormalities and previous operations.

Does the femoral head/neck contour in the skeletally mature change over time?

The purpose of this study was to determine whether anterior/anterolateral femoral head/neck contour of the hip is static or dynamic over time within the context of the cam deformity. From a previously published cohort of 200 asymptomatic patients who had a magnetic resonance imaging (MRI) of their hips, 23 patients were randomly selected: 10 with a cam lesion and 13 with no evidence of a cam lesion in either hip. There were 7 females and 16 males with a mean age of 37.5 years (range 30-56 years). A repeat MRI or computed tomography scan was performed. Femoral head/neck contour was assessed with alpha angle measurements at the 3 and 1:30 positions. At mean time of 5.3 years (range 2.5-7.2 years) between the two time points, the mean alpha angle for the entire cohort was not significantly different with alpha angle of 43.4°/53.7° (3:00/1:30 positions) at first visit and 46.1°/54.2° (3:00/1:30 positions) at second visit, respectively. Subdividing the cohort into cam negative and cam positive groups, there are no clinically relevant differences (i.e. <5°) between the two alpha angle measurements. Inter-observer reliability had an intra-class coefficient at 0.96 (95% CI: 0.94-0.97). Neither group of patients demonstrated clinically relevant change in the alpha angle. Consequently, screening at time of skeletal of maturity would be an efficient means of identifying individuals for a possible cam deformity.

Reconstruction of patellar tendon following implantation of proximal tibia megaprosthesis for the treatment of post-traumatic septic bone defects.

INTRODUCTION: Latest advances made in joint replacement implants allows reconstruction of entire limbs. These special prostheses or megaprostheses were originally designed for the treatment of severe oncological bone loss. Nowadays, however, the indications and applications of these devices are expanding to other orthopaedic and trauma clinical conditions. Since 2008 we have implanted 152 megaprostheses in non-oncological conditions: 87 were implanted for post-traumatic failures aseptic/septic (represented by complex non-unions and critical size bone defects); 26 total femur, 52 distal femur and 9 proximal tibia. In this group of patients bone and soft tissues conditions are completely different compared to patients with oncological back ground. The presence of infection and previous surgeries can lead to adhesion, scar interference, muscular and tendon impairment and skin problems that lead to reduced function and severe joint stiffness. The purpose of this study is to evaluate the results of treatment of reconstruction of patellar tendon during implantation of proximal tibia megaprosthesis for the treatment of septic post traumatic critical bone defects. PATIENTS AND METHODS: In this retrospective study, we evaluated 9 patients treated with proximal tibia megaprosthesis who underwent patellar tendon reconstruction. All patients presented a complete patellar tendon disruption at the time of prosthesis implantation. Procedures of reconstruction included a tendon-plasty of quadriceps and/or patellar tendons, a pie crusting of quadriceps fascia, a reinforcement of the apparatus with synthetic tendon graft substitutes (LARS) and a medial gastrocnemius muscular flap to reconstruct the extensor mechanism and obtain skin coverage when needed. The average follow up was 18 months (9-36). For each of the cases, we analysed the complications occurred regarding septic recurrence, patellar fracture, quadriceps and patellar tendon rupture and number of reinterventions. The clinical outcome was assessed by the WOMAC Score. RESULTS: In all cases there was no infection recurrence or skin related problems. None of the patients require prosthesis revision due to loosening or device failure. No patellar fracture or quadriceps tendon failure was recorded. One patient presented a rupture of the reconstructed patellar tendon due to a trauma incident 18 months after the implantation and he required revision surgery. From a clinical point of view the average WOMAC score was 62.4 at 1 month rising to 72.6 at 3 months, 78.2 at 6 months, 76.4 at 1 year and 74.8 at 18 months. CONCLUSION: When proximal tibia megaprosthesis is implanted and there are soft tissue and patellar tendon deficiency, soft tissue reconstruction can be achieved by appropriate lengthening of the tendon and a gastrocnemius flap reinforced by LARS. Such an approach allows restoration of the extensor mechanism and coverage of the prosthesis in an area where skin problems are frequently very common.

Primary total knee arthroplasty twenty years after distal femoral cement augmentation of a giant cell tumor.

We present a case of knee reconstruction 20 years after treatment of a giant cell tumor (GCT) with curettage and cementation. There is currently an ongoing debate whether cement or allograft bone is the preferred material for filling the void after GCT curettage. In this case we were able to readily implant a primary total knee replacement without disturbing the existing well-interdigitated large cement bolus and did not require any stems or augments for the reconstruction. Given the ease of TKR implantation in this patient, we feel that the use of cement following curettage of a GCT lesion is a better choice than allograft bone which may not provide enough structural support for the knee reconstruction and lead to a much more extensive procedure.

Surgical treatment of partial anterior cruciate ligament lesions: medium-term results.

PURPOSE: this study was conducted to evaluate subjective and objective clinical outcomes of partial reconstruction of the anterior cruciate ligament (ACL) in comparison with complete ACL reconstruction. METHODS: three groups, each comprising 20 patients, were evaluated at a minimum follow-up of 12 months. The group 1 patients underwent partial ACL reconstruction, while those in group 2 and group 3 underwent complete ACL reconstruction, performed using either bone-patellar tendon-bone (BPTB) or quadrupled hamstring tendon (HT) grafts, respectively. The subjective outcome was evaluated using the Lysholm knee scale and the subjective International Knee Documentation Committee (IKDC) scoring system. A visual analog scale (VAS) was used for pain assessment and sporting activity was rated using the Tegner activity scale. Objective evaluation was performed using the IKDC objective form, KT-1000 arthrometer and KiRA triaxial accelerometer. RESULTS: at the follow-up evaluation, the mean subjective IKDC score was 86.1±10.3 in group 1, 85.2±11.1 in group 2, and 82.7±7.8 in group 3. The Lysholm score was 91.3±7.3 in group 1, 91.7±9.6 in group 2, and 89.4±6.1 in group 3. KT-1000 tests showed a mean side-to-side difference of 1.1 mm ± 1.5 mm (range, 0-5 mm) in group 1; 0.79 mm ± 0.8 mm (range, 0-2mm) in group 2; and 1.45 mm ± 1 mm (range, 0-3 mm) in group 3. The differences between groups were not statistically significant. CONCLUSIONS: both subjective and objective outcomes of partial ACL reconstruction were comparable to those of complete reconstruction, but partial reconstruction in the presence of a partial lesion of the ACL is considered by the authors to be more respectful of the native vascularization, innervation and anatomy of the ACL, conferring an advantage in terms of recovery of the complete function of the knee. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

A randomized double-blind clinical trial on the treatment of knee osteoarthritis: the efficacy of polynucleotides compared to standard hyaluronian viscosupplementation.

BACKGROUND: This randomized, double-blind, parallel-group clinical trial aims to assess the equivalence of intra-articular polynucleotides compared to standard hyaluronic acid (HA) viscosupplementation in the treatment of knee osteoarthritis (OA). METHODS: 75 patients affected by knee OA were assessed for eligibility and 72 were enrolled and randomized to receive either intra-articular polynucleotides (Condrotide-36 patients) or hyaluronic acid (Hyalubrix-36 patients) at the Orthopedic Institute "Gaetano Pini" (Milan). All patients underwent three intra-articular injections of Condrotide or Hyalubrix with an interval of 1week. Participants, care givers, and investigators responsible for outcome assessment were all blinded to group assignment. Primary outcome measurements (KOOS and pain level (1) at rest, (2) at weight-bearing and (3) during physical activity) were evaluated at baseline (T0) and after one (T1), two (T2), six (T6), ten (T10), and 26 (T26)weeks. Secondary measurements included the determination of COMP serum levels at T0, T6 and T26. RESULTS: The reduction of pain and the increase of KOOS values from baseline were statistically significant for both treatments; nevertheless, for parameter KOOS "symptoms" the treatment with Condrotide showed significant results already after twoweeks (at T2 p=0.003) while the results obtained with Hyalubrix became significant only after 18 weeks (at T18 p=0.01). No significant adverse events were reported. CONCLUSIONS: Condrotide is as effective as Hyalubrix in reducing knee OA symptoms but showed an earlier response on pain reduction and can therefore be considered a valid alternative to the use of HA in the treatment of OA, avoiding the adverse events of NSAIDs and of intra-articular corticosteroids.

Patellofemoral instability: classification and imaging.

Patellofemoral disorders must be approached through an appropriate process of diagnostic framing, performed using language that is, as far as possible, unequivocal and a validated and organic classification system. At present, the classification proposed by the Lyonnaise school, which fulfills these requirements, is the most complete. This classification divides patellofemoral disorders into three groups: objective patellar instability, potential patellar instability and painful patella syndrome. It also identifies three principal factors of instability: trochlear dysplasia, abnormal patellar height and pathological tibial tubercle-trochlear groove (TT-TG) distance. Imaging is crucial for correct classification and for identifying and measuring the principal factors of instability. Up to now, the emphasis has been placed on the contribution made by traditional diagnostic radiology and computed tomography. In recent years, however, growing attention has been paid to the use of magnetic resonance imaging in the assessment of the patellofemoral joint and in the study of factors of instability, even though there is still a need for validation of this approach before it can be routinely used in preoperative planning.