Managing of post-traumatic knee arthritis by total knee arthroplasty: case series of 15 patients and literature review

Porous metal block based on topology optimization to treat distal femoral bone defect in total knee revision

Metal block augmentations are common solutions in treating bone defects of total knee revision. However, the stress shielding and poor osteointegration resulted from metal block application could not be neglected in bone defects restoration. In this study, a novel porous metal block was designed with topology optimization to improve biomechanical performance. The biomechanical difference of the topologically optimized block, solid Ti6Al4V block, and porous Ti6Al4V block in treating bone defects of total knee revision was compared by finite element analysis. The inhomogeneous femoral model was created according to the computed tomography data. Combined with porous structures, minimum compliance topology optimization subjected to the volume fraction constraint was utilized for the redesign of the metal block. The region of interest was defined as a 10 mm area of the distal femur beneath the contacting surface. The biomechanical performance of daily motions was investigated. The von Mises stress, the strain energy density of the region of interest, and the von Mises stress of metal blocks were recorded. The results were analyzed in SPSS. In terms of the region of interest, the maximum von Mises stress of the topological optimized group increased obviously, and its average stress was significantly higher than that of the other groups (p < 0.05). Moreover, the topologically optimized block group had the highest maximum strain energy density of the three groups, and the lowest maximum stress of block was also found in this group. In this study, the stress shielding reduction and stress transfer capability were found obviously improved through topology optimization. Therefore, the topological optimized porous block is recommended in treating bone defects of total knee revision. Meanwhile, this study also provided a novel approach for mechanical optimization in block designing.

Accelerometer-Based Navigation versus Conventional Total Knee Arthroplasty for Posttraumatic Knee Osteoarthritis

BACKGROUND

Posttraumatic osteoarthritis (PTOA) frequently comprises femoral or tibial deformity, which makes it difficult to perform total knee arthroplasty (TKA). Accelerometer-based navigation (ABN) could be effective in restoring a neutral mechanical axis (MA) in TKA, but a limited number of studies have been reported in association with PTOA. Therefore, we aimed to compare the lower limb MA between ABN-assisted TKA (ABN-TKA) and conventional TKA in patients with PTOA.

METHODS

We conducted a retrospective analysis of 28 PTOA patients who underwent TKA using a conventional system (cTKA group, n = 16) and the ABN system (iTKA group, n = 12). Standing long-leg radiographs were assessed for MA and prosthesis alignment as primary outcomes. A postoperative MA deviating beyond ± 3° was defined as an outlier. Perioperative outcomes, Oxford Knee Score (OKS) at 2-year follow-up, and complications were also assessed.

RESULTS

The cTKA group and the iTKA group had a mean age of 63.07 years and 65.25 years, respectively. The iTKA group had significantly better MA accuracy when compared to the cTKA group (1.60° ± 2.09° vs. 3.59° ± 1.34°, p = 0.01). The iTKA group showed significantly less MA outlier than the cTKA group (78.6% vs. 25.0%, p = 0.02). The prosthesis alignment and OKS were comparable between the groups. There were 2 periprosthetic joint infections in the cTKA group and 1 periprosthetic fracture of the distal femur in the iTKA group.

CONCLUSIONS

For PTOA of the knee, both conventional TKA and ABN-TKA significantly improved the postoperative mechanical alignment and functional outcomes. The ABN-TKA seemed to offer higher accuracy and less MA outlier when compared to conventional TKA, and thus ABN could be a good alternative option.

Outcomes of Total Knee Arthroplasty in Patients with Prior Hardware: A Case-Control Study Using Handheld Navigation

Presence of hardware in juxta-articular location poses challenge during total knee arthroplasty (TKA). When present in distal femur, it precludes the use of an intramedullary femoral jig during TKA often necessitating removal of hardware leading to prolonged surgery, higher risk of complications, and inferior results. We conducted a case-control study to assess the outcome of TKA among patients with post-traumatic arthritis using a handheld navigation system to perform bone cuts allowing retention of hardware in situ. In 15 patients with post-traumatic arthritis and hardware around the knee (Group A), none or part(s) of hardware were removed while performing TKA. These patients were matched to 15 patients who underwent TKA with handheld navigation for primary OA knee (Group B). The perioperative outcomes assessed were operative time, intraoperative blood loss, length of hospital stay, complications, and 30 days reoperation rate. Clinical outcomes were assessed by using Knee Society Score (KSS) and radiological outcomes using mechanical axis and coronal and sagittal component angles. Mean age of patients at surgery were 65.67 years (Group A) and 66.73 years (Group B). Mean operative time and blood loss were significantly higher in Group A as compared with Group B. At the mean follow-up of 34 months, KSS significantly improved in both the groups. However, there was no statistically significant difference in the clinical and radiological outcomes between the two groups. One patient in Group A developed wound dehiscence and had to undergo debridement and flap coverage within 30 days. The use of navigation helps surgeons in gaining proper limb alignment and implant positioning without complete removal of hardware.

Application Value of Total Knee Arthroplasty plus Platelet-Rich Plasma Therapy in Traumatic Arthritis of the Knee

Purpose

This work is aimed at determining the application value of platelet-rich plasma (PRP) therapy plus total knee arthroplasty (TKA) in traumatic arthritis (TA) of the knee.

Methods

A retrospective study was conducted on 78 cases of TA of the knee admitted between March 2021 and January 2022 to the Quanzhou First Hospital Affiliated to Fujian Medical University. Based on different treatment methods, 38 cases treated with TKA were assigned to the control group, and 40 cases intervened by PRP+TKA were included in the observation group. The operation time (OT), drainage volume (DV), total blood loss (TBL), incision inflammatory reaction rate, and grade A healing rate were recorded. Besides, preoperative and postoperative knee joint Hospital for Special Surgery (HSS) scores, knee joint pain assessed by visual analogue scale (VAS), knee joint range of motion (ROM), and bone metabolism parameters (osteocalcin (OST), total N-terminal propeptide of type I procollagen (tPINP), and β-isomerized C-terminal telopeptides (β-CTX)) were recorded.

Results

The observation group showed reduced postoperative DV and TBL than the control group (P < 0.05). The two cohorts differed insignificantly in OT, incision inflammatory response rate, and grade A healing rate (P > 0.05). The observation group also had better improvement in the HSS score, pain VAS score, and knee ROM (P < 0.05). And higher postoperative OST and tPINP levels while lower β-CTX were determined in the observation group (P < 0.05).

Conclusions

PRP+TKA can validly improve the levels of bone metabolism markers in patients with TA of the knee and promote their knee functional recovery, with favorable safety.

Biomechanical Comparison Between Porous Ti6Al4V Block and Tumor Prosthesis UHMWPE Block for the Treatment of Distal Femur Bone Defects

Purpose: The management of bone defects is a crucial content of total knee revision. This study compared the biomechanical performance of porous Ti6Al4V block and tumor prosthesis UHMWPE block in treating distal femoral bone defects.

Methods: The finite element models of AORI type 3 distal femoral bone defect treated with porous Ti6Al4V block and UHMWPE block were established. Sensitivity analysis was performed to obtain the appropriate mesh size. The biomechanical performance of treatment methods in bone defects were evaluated according to the peak stress, the Von Mises stress distribution, and the average stresses of regions of interest under the condition of standing on one foot and flexion of the knee. Statistical analysis was conducted by independent samples t-test in SPSS (p < 0.05).

Results: In the standing on one-foot state, the peak stress of the porous Ti6Al4V block was 12.42 MPa and that of the UHMWPE block was 19.97 MPa, which is close to its yield stress (21 MPa). Meanwhile, the stress distribution of the UHMWPE block was uneven. In the flexion state, the peak stress of the porous Ti6Al4V block was 16.28 MPa, while that of the UHMWPE block was 14.82 MPa. Compared with the porous Ti6Al4V block group, the average stress of the region of interest in UHMWPE block group was higher in the standing on one foot state and lower in the flexion state (p < 0.05).

Conclusion: More uniform stress distribution was identified in the porous Ti6Al4V block application which could reserve more bone. On the contrary, uneven stress distribution and a larger high-stress concentration area were found in the UHMWPE block. Hence, the porous Ti6Al4V block is recommended for the treatment of AORI type 3 distal femoral bone defect.

A randomized control trial on retro-walking improves symptoms, pain, and function in primary knee osteoarthritis

BACKGROUND

Primary knee osteoarthritis is the leading cause of chronic disability and pain among adults worldwide. Retro-walking has been shown to reduce patellofemoral pain, increases functional capability while strengthening the lower limbs and improving proprioception and balance. We aim to examine the effects of retro-walking on symptoms, pain, and perceived ability to perform daily activities in comparison to forward-walking in subjects with primary knee osteoarthritis.

METHODS

This was a single-blinded, randomized control trial involving 34 subjects between the age of 45-70 years (58.41±5.93) comparing retro-walking (RW) to forward-walking (FW). Subjects were randomly allocated to receive either RW with structured resistance training (SRT) or FW with SRT; 3 times a week for 12 weeks. The symptoms, pain, and function of daily living sub scores of the Knee Injury and Osteoarthritis Outcome Score (KOOS) along with Timed up and go (TUG) and Chair stand test (CST) were assessed at baseline and after 12 weeks. The outcomes were analyzed with two-way repeated measure analysis of variance.

RESULTS

Significant improvements for all outcomes were observed intra-group (P value <0.05) after 12 weeks. The KOOS sub scores, TUG and CST times was not statistically significant between study groups (P value >0.05). However, the partial eta squared scores for all outcomes were better in the RW group compared to FW except for CST.

CONCLUSIONS

It can be concluded that RW is a feasible and non-inferior option to FW in the rehabilitation of subjects with bilateral knee OA.

Effects of proximal fibular osteotomy on stress changes in mild knee osteoarthritis with varus deformity: a finite element analysis

BACKGROUND

Many previous studies lack sufficient quantitative evidences about changes in biomechanical properties of the knee in response to proximal fibular osteotomy (PFO). Therefore, the aim of this study was to compare the preoperative and postoperative effects of PFO on mechanical stresses in the knee joint and provide with a biomechanical basis for PFO in the treatment of mild knee osteoarthritis (KOA) with varus deformity.

METHODS

A total of 10 patients suffering mild KOA with varus deformity were enrolled in this study. Their image data from computerized tomography (CT) and magnetic resonance imaging (MRI) were used for finite element models, and PFO models were established. Static structural analysis was carried out using ABAQUS to compare the von Mises stress distribution and values of the maximal von Mises stress of femoral cartilage, meniscuses, tibial cartilages, and tibial plateau before and after surgery.

RESULTS

The stress distribution in the cortical bone of the tibial plateau showed that stresses were transferred from the anterior medial area to the posterior medial area after PFO. Values of the maximal von Mises stress in femoral cartilage, medial meniscus, medial tibial cartilage, and tibial plateau after surgery were significantly lower than the preoperative values, with statistically significant differences (P < 0.05). Postoperative values of the maximal von Mises stress of lateral meniscus and lateral tibial cartilage were significantly higher than the preoperative ones, with statistically significant differences (P < 0.05).

CONCLUSION

PFO could reduce the stresses in the medial compartment of the knee joint with stress pathways transferring from the anterior medial area to the posterior medial area of the tibial plateau. Therefore, PFO is recommended for the treatment of mild KOA with varus deformity featuring favorably pain-relieving effects.