Medial tibial bone resorption following total knee arthroplasty comparing a traditional with a kinematic design.

BACKGROUND: New total knee prostheses are being designed to improve clinical outcome, survivorship and patient satisfaction following total knee arthroplasty (TKA). A new knee system was developed with improvements in patellofemoral joint, trochlear geometry, polyethylene formulation and tibial baseplate. Aim of this study was to compare the newer kinematic knee system with its existing predecessor knee system in terms of clinical outcome, revision rates, radiographic outcomes specifically medial tibial bone resorption. METHODS: The prospective matched-pair study included 88 TKA surgeries using newer kinematic design knee prostheses, performed between January 2015 and December 2016, out of which 82 patients were available for final follow-up. The control cohort of 82 traditional TKA prosthesis was matched in terms of age, gender and body mass index. All surgeries were performed by the single surgeon using medial parapatellar arthrotomy and posterior stabilized implants were used. Clinical outcomes were assessed using knee society score, range of motion (ROM), anterior knee pain and crepitation. Radiological examinations included recording of radiolucent lines and medial tibial bone resorption. RESULTS: At the 5-year follow-up, no significant differences were noted in terms of mean knee society score (93.3 ± 6.6 vs 94.2 ± 8.1), knee function score (88.5 ± 10.5 vs 89.1 ± 11.2) and ROM. The incidences of anterior knee pain and crepitation were lower in the newer group (8.5% vs 21.9% and 14.6% vs 32.9%, respectively) compared to the traditional prosthesis group. No cases of aseptic loosening were observed in either cohort. No significant difference was seen in terms of radiolucent lines (29.3% vs 26.8%) and medial tibial resorption (2.43% in each group) incidences. CONCLUSIONS: At the 5 years follow-up no significant differences were noted between the two groups in terms of clinical and radiological outcomes, except the former proved to be better for anterior knee pain and crepitation. LEVEL OF EVIDENCE: II.

The application of low-dose dexamethasone in total knee arthroplasty: finding out the best route and dosage schedule.

BACKGROUND: The use of dexamethasone as additive to multimodal analgesic regimen in total knee arthroplasty has been well established, but the most suitable route, effectiveness, safety and dose schedule of low-dose dexamethasone is not known. METHODS: We conducted a prospective, randomized, double-blinded trial to investigate and compare the analgesic and antiemetic effects and safety of low-dose (8 mg) dexamethasone introduced as periarticular injection or intravenous (as a single dose or in two divided doses of 4 mg separated by 24 h) in unilateral total knee arthroplasty patients. RESULTS: The single dose intravenous administration as well as the periarticular administration of dexamethasone had similar mean visual analogue scores which were significantly lower than divided dose group at 24 and 48 h postoperatively. The rate of postoperative nausea and vomiting was lowest among single intravenous dose group and highest among interval dose group at 24 h, while no difference was noted at 48 h. No significant differences were noted in terms of knee flexion angle at 48 h and modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score at 6 weeks. CONCLUSION: Single low-dose intravenous dexamethasone is the most appropriate dose which can safely be given to TKA patients and is only moderately associated with rise in blood sugar not causing any significant complication. Alternatively, periarticular infiltration of low-dose dexamethasone can produce equivalent analgesic effect as SDIV in first 24 h without causing significant blood sugar rise and wound complications, but its antiemetic effect remains subtle. Therefore, it is recommended to further study the combination of intraoperative periarticular and postoperative intravenous dexamethasone for their possible additive effect.

Analysis of clinical and radiological outcomes of long tibial stemmed total knee arthroplasty in knee osteoarthritis complicated by tibial stress fracture.

OBJECTIVE: Knee arthritis associated with tibial stress fractures represents an uncommon and difficult clinical scenario to treat. The use of long, fluted tibial extension rods has been vital in the management of such cases owing to immediate fracture stability and single-stage surgery without the need to open the fracture site. This study investigates clinical and radiological outcomes following total knee arthroplasty using a tibial extension stem in cases of knee osteoarthritis with tibial stress fracture. METHODS: From February 2015 to December 2020, 17 patients who had total knee arthroplasty implanted with a long stemmed tibial component were included in the study. Patient data were analyzed for knee range of motion, deformities, Knee Society score, knee function score, and time to fracture union in the pre- and postoperative periods. RESULTS: The mean follow-up duration was 22.7 ± 11.68 months (range 12-60 months), and mean time to fracture healing was 10.23 ± 2.81 weeks (range 8-20 weeks). The preoperative mean fixed flexion deformity improved from 8.53 ± 3.43° to a mean of 0.29°, and knee flexion improved from 79.4 ± 13.90° to 125.29 ± 8.74° on postoperative assessment. The Knee Society score improved from a mean preoperative score of 18.94 ± 5.55 (range 8-28) to 89.41 ± 7.5 (range 74-102, p value < 0.001). Similarly, the knee function score improved significantly from a mean preoperative score of 15.5 ± 4.48 (range 8-26) to a mean of 85 ± 6.09 (range 72-94, p value < 0.001). CONCLUSION: Total knee arthroplasty using long tibial extenders has been an effective and safe surgical option for patients with advanced osteoarthritis with tibial stress fractures.

Clinical and Surgical Insights on Bilateral Total Knee Arthroplasty in Ochronotic Arthropathy: A Case-based Review.

Introduction: Ochronotic arthropathy (OcA) is a consequence of alkaptonuria, a rare systemic-inherited metabolic disorder leading to accumulation of homogentisic acid in articular cartilage and subsequent early degeneration of the joints. Only few cases of OcA managed with bilateral total knee arthroplasty (TKA) has been described in the literature so far. We aim to discuss surgical pearls, pitfalls, and clinical outcome of OcA of knees managed with simultaneous bilateral TKA. Case Presentation: The patient was a 52-year-old female presented to outpatient facility with severe bilateral knee pain and difficult ambulation. After clinical and radiological diagnosis of osteoarthritis, she was posted for bilateral TKA. During arthrotomy, blackening of articular cartilage, quadriceps and patellar tendon, and synovium was noted. Subchondral bone was free of pigmentation though, seemed osteopenic while taking bone cuts. Right knee was implanted with cruciate retaining components with ultracongruent insert; while on the left side, posterior stabilized components were used. Diagnosis of ochronosis was made retrospectively with characteristic subtle pigmentation of nails, palms, pinnae, and urine homogentisic levels. Two years follow-up of the patient remained satisfactory without any major complications. Conclusion: OcA may present with intra-operative surprise to the surgeon if not anticipated preoperatively. Simultaneous bilateral TKA is safe and effective treatment for end-stage arthritis. However, it is difficult to diagnose it preoperatively; a high clinical suspicion leads to meticulous assessment and counseling regarding potential anesthetic concerns, choice of implant, and possible intra-operative and post-operative complications reported sporadically though.