Acesso lateral de Keblish melhora a inclinação da patela na artroplastia do joelho valgo

How to optimize patellar tracking in knee arthroplasty?

Good patellar tracking is needed for functionally successful total knee arthroplasty (TKA), and depends on several factors. The aim of the present Instructional Lecture is to identify the main factors and how to control them so as to optimize patellar tracking: more or less "patella-friendly" prosthetic trochlea design, requiring precise assessment and choice of model; patellar component design; type of tibial implant; surgical approach and management of peripatellar structures, and any lateral release; distal and posterior femoral bone cuts, determining femorotibial alignment, femoral component rotation and patellar height; tibial implant rotation with respect to the anterior tibial tubercle; patellar cut characteristics in resurfacing. In case of instability or patellar maltracking despite correct implant positioning, there are 2 main surgical techniques: medial patellofemoral ligament reconstruction, and anterior tibial tubercle medialization. To obtain optimal patellar tracking, correction of other factors should be associated: trochlear component design, distal and posterior femoral bone cuts, tibial implant positioning, patellar component shape and positioning, etc.

Lateral approach total knee arthroplasty achieves equivalent patellar tracking in severe valgus deformity compared to mild valgus deformity

PURPOSE

Patellar tracking problems represent 2-10% of complications of total knee arthroplasties (TKA) in valgus knees. However, there are no studies assessing patellar tracking according to the severity of the valgus deformity. The hypothesis was that lateral approach TKA in severe valgus deformity provides equivalent patellar tracking to that in knees with mild valgus deformity.

METHODS

Between 1988 and 2016, 77 TKAs were performed via a lateral approach on a severe valgus deformity (HKA > 195°). Forty-three TKAs performed without tibial tubercle osteotomy and with complete radiological data were included in this study. These were compared with 86 matched TKAs performed via a lateral approach with a mild valgus deformity (HKA between 181° and 190°). Patellar tilt and patellar position were assessed by axial view radiographs at the last follow-up. Complications and clinical outcomes were also evaluated.

RESULTS

The follow-up was mean 52 ± 21 months in the severe valgus group. No significant differences were found between the severe valgus deformity group and the mild valgus deformity groups in patellar tilt (1.6° ± 6.6° versus 1.9° ± 3.2°, respectively) or patellar subluxation. There were complications in 12% (n = 5) and 11% (n = 9) of the severe valgus group and the mild valgus group respectively, without significant difference. There was no significant difference in extensor mechanism complication rate (2.3% versus 4.7%, respectively).

CONCLUSION

Lateral parapatellar approach, without tibial tubercle osteotomy, for TKA in severe valgus deformity results in good patellar tracking. With this approach, the extensor mechanism complication rate in severe valgus deformity was not higher than for mild valgus deformity.

LEVEL OF EVIDENCE

III.

Patellofemoral Arthroplasty Surgical Technique: Lateral or Medial Parapatellar Approach

BACKGROUND

Patellofemoral arthroplasty (PFA) is an emerging treatment for patients with isolated patellofemoral compartment osteoarthritis. The medial parapatellar approach is the standard arthrotomy but has been shown in total knee arthroplasty to damage the patellar blood supply and increase postoperative patellar instability. The lateral parapatellar approach is an alternative that may reduce the risk of these outcomes. The purpose of this study is to compare the radiographic measures of patellar tracking and patient-reported outcomes of the medial and lateral parapatellar approaches in PFA.

METHODS

Between 2012 and 2019, a retrospective review was performed of 136 knees undergoing PFA at a single institution. Patients were separated by preoperative congruence angle and then surgical approach into 3 cohorts. Preoperative and postoperative patellar tilt and congruence angle were measured. Preoperative and minimum 6-month postoperative patient-reported outcomes scores were collected.

RESULTS

There were no significant differences in the mean postoperative congruence angle and postoperative patient-reported outcomes among the 3 cohorts. Mean postoperative patellar tilt was normalized only in the abnormal congruence angle/lateral approach group to 2.80° (standard error, 1.85).

CONCLUSION

Congruence angle was improved regardless of surgical approach. Patellar tilt was normalized only for the lateral approach in patients with abnormal preoperative congruence angle. There were no significant differences in preoperative and postoperative scores between groups except for preoperative 12-item Short Form Mental Health Survey scores. This study supports that the lateral approach offers improved postoperative patellar tilt compared to a medial approach for PFA while achieving similar patient-reported outcomes.

Total Knee Arthroplasty for Valgus Deformity via a Lateral Approach: Clinical Results, Comparison to Medial Approach, and Review of Recent Literature

BACKGROUND

Total knee arthroplasty (TKA) for valgus deformity is a challenge. The standard medial parapatellar approach may not be universally useful for this. We have adopted the lateral approach to valgus knees. Here we describe our experience with this approach, present early results, and compare them to the medial approach.

METHODS

Our institutional registry was queried for all patients with valgus deformity who underwent a TKA via a lateral approach between 2013 and 2016. The registry was also queried for patients with valgus deformity who underwent a TKA through a medial approach in previous years and this data was compared to the study group.

RESULTS

Seventy-nine valgus knees in 72 patients were operated through a lateral approach. Deformity was corrected by 10.8°, from 16.2° to 5.4° (P < .001). Patellar tilt improved from -2.3° to 0.3° (P = .037). Seven implants (9%) were constrained. Mean operating time was 87 minutes (range 53-137). Twenty-five knees in 23 patients were operated via the medial approach. Deformity was corrected by 7.3°, from 13.2° to 5.9° (P < .001). Mean operating time was 137 minutes (range 90-230). Constrained implants were used in 16% of cases. The lateral approach allowed better correction of valgus deformity (10.8 vs 7.3, P = .03) and shorter operative times (87 vs 137 minutes, P < .001).

CONCLUSION

A lateral approach TKA for valgus deformity improves knee alignment and patellar tilt. Compared to the medial approach, it allows better correction of the deformity, shorter operating times, and perhaps less use of constrained implants.

The lateral and medial approach in total arthroplasty for valgus knee: a meta-analysis of current literature

Aim: To compare the lateral and medial approaches of total knee arthroplasty (TKA) in the valgus knee. Materials & methods: An electronic search from the PubMed, Embase, Web of Science and Cochrane library was performed according to 'TKA', 'valgus', 'knee' and 'approach'. Subsequently, manual search was conducted from the reference lists in the identified studies. Results: Four randomized controlled trials and five cohorts were included. Better knee society score and function was noticed in patients after lateral approach. Similar postoperative valgus deformity, operative time, blood loss, Western Ontario and McMaster Universities Osteoarthritis Index, range of motion, pain and total complications in both groups. Conclusion: Compared with the medial approach for TKA in valgus knee, current data shows superior results after TKA by the lateral approach.

Lateral or medial approach for valgus knee in total knee arthroplasty - which one is better? A systematic review

Objective

To identify whether the medial or lateral approach is superior for patients with valgus knees undergoing primary total knee arthroplasty (TKA).

Methods

Studies evaluating the 2 approaches were sourced from the PUBMED, EMBASE, Web of Science, and OVID databases. The quality of included studies was assessed using a modified quality evaluation method, and differences between approaches were systematically reviewed.

Results

Seventeen observational studies were included. The studies were published between 1991 and 2016, and included 5 retrospective studies and 12 prospective studies. Sixteen evaluation methods for the study outcomes were identified. Twelve and eight complication types were identified by studies reporting the lateral and medial approaches for valgus knee, respectively. Several studies showed that pain scores and knee function were superior using a lateral approach.

Conclusion

The lateral approach (combined with a tibial tubercle osteotomy or proximal quadriceps snip) was more useful and safer than the medial approach in the treatment of severe uncorrectable valgus knee deformity in patients undergoing TKA. Most of the available evidence supports the use of a lateral approach provided that the surgeon is familiar with the pathological anatomy of the valgus knee.