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Average 4.1 of 18 Ratings
A 70-year-old female has persistent anterior knee pain and stiffness 10 months status-post total knee arthroplasty with associated lateral patellar release. Radiographs before and after surgery are shown in Figures A and B respectively. Pre-operatively, her Insall-Savati ratio is 0.95, compared to 0.76 post-operatively. Which of the following is the most likely cause of her radiographic abnormality and pain?
Notching of the femur
Excessive resection of the distal femur and lateral release of the patella
Preoperative patella baja
Excessive release of the patellar ligament from the tibial tubercle
Excessive resection of the proximal tibia
Select Answer to see Preferred Response
Figure B represents iatrogenic patella baja and an elevated joint line caused by excessive resection of the distal femur and contracture of the patellar tendon likely as a result of lateral patellar release. Figure A does not demonstrate pre-operative patellar baja, and answer choices 4 and 5 would lead to patella alta. The Insall-Savati ratio, shown in Illustration A, is the ratio of the patella tendon length to the length of the patella. A value <0.8 is cosistent with patella baja, and a value >1.2 is consistent with patella alta.
Weale et al reviewed serial radiographs of 84 patients who had had either TKR or UKR to determine the change in patellar tendon length up to 5 years post-operatively. They found that tendon shortening was greatest in those knees which underwent TKA and had required a lateral release.
Figgie et al correlated patellofemoral symptoms with the postion of the implant in 116 posterior stabilized condylar knee prostheses. They concluded that keeping the line of the prosthesis 8mm or less from the natural joint line keeps the flexors and extensors of the knee operating at their optimum length-tension relationship, and provided the best outcomes.
Partington et al performed radiographic review of joint line position before and after revision total knee arthroplasty, and compared it with the joint line position before primary knee arthroplasty. They found that joint line elevation >8mm correlated with worse knee scores post-operatively, and distal femoral augments may be necessary in revision situations.
Figgie HE 3rd, Goldberg VM, Heiple KG, Moller HS 3rd, Gordon NH.
J Bone Joint Surg Am. 1986 Sep;68(7):1035-40. PMID: 3745240 (Link to Abstract)
Partington PF, Sawhney J, Rorabeck CH, Barrack RL, Moore J.
Clin Orthop Relat Res. 1999 Oct;(367):165-71. PMID: 10546611 (Link to Abstract)
Weale AE, Murray DW, Newman JH, Ackroyd CE.
J Bone Joint Surg Br. 1999 Sep;81(5):790-5. PMID: 10530838 (Link to Abstract)
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Average 2.0 of 39 Ratings
A 25-year-old healthy, active male undergoes lateral closing wedge high tibial osteotomy. Which of the following complaints is most commonly associated with this procedure?
Anterior knee pain
The most common complaint associated with lateral closing wedge high tibial osteotomy is anterior knee pain.
Lateral closing wedge high tibial osteotomies are commonly associated with anterior knee pain due to the high incidence of patella baja post-operatively. Patella baja is characterized by the lowering of the patella relative to its normal position, which is typically measured using the Insall-Salvati ratio of < 0.8 (Normal ratio = 0.8 - 1.2). The most common symptoms associated with patella baja include anterior impingement, knee pain, and knee stiffness.
Scuderi at al. evaluated the effect of proximal tibial osteotomy on patellar height in 66 patients. They found that patellar height decreased by 89%, as measured by the Insall-Salvati index, and 76.3%, as measured by the Blackburne-Peel index, post-operatively.
Wright et al. reviewed the complications associated lateral closing wedge and medial opening wedge high tibial osteotomy. They reported a 64% incidence of patella baja following these high tibial osteotomy techniques, with associated complaints of anterior knee pain.
Illustration A shows an X-Ray of patella baja after closed wedge high tibial osteotomy. The Insall-Salvati ratio is determined by measuring the ratio of patella tendon length (TL) to the length of the patella bone (PL) with the knee flexed at 30 deg.
Answer 1: Knee stiffness, not laxity, is more common after high tibial osteotomy.
Answer 2: The incidence of deep infection is roughly 0 - 4%.
Answer 4: Quadriceps weakness typically exists prior to high tibial osteotomy.
Answer 5: Leg shortening is more likely associated with lateral closing wedge high tibial osteotomy.
Scuderi GR, Windsor RE, Insall JN.
J Bone Joint Surg Am. 1989 Feb;71(2):245-8. PMID: 2918009 (Link to Abstract)
Wright JM, Heavrin B, Begg M, Sakyrd G, Sterett W
Am J Knee Surg. 2001 14(3):163-73. PMID: 11491427 (Link to Abstract)
Average 3.0 of 14 Ratings
A patient who has previously undergone a high tibial osteotomy 10 years prior is scheduled for a total knee arthroplasty (TKA). Which of the following factors is most likely to be present and may complicate the arthroplasty?
Collateral ligament instability
Patellar tendon insufficiency
Severe varus deformity
TKA after a high tibial osteotomy (HTO) can be more difficult to perform than a primary knee replacement because of a shift of the proximal tibial articular surface in relation to the medullary canal, retained hardware, previous skin incisions, scar tissue, and altered patellofemoral mechanics caused by patella baja and contraction of the patella tendon. The frequency of valgus deformity is greater following HTO.
Parvizi et al reviewed 166 TKA's performed following a high tibial osteotomy. A higher rate of component loosening was observed with 8% revision at 5.9 years follow-up. Male gender, preoperative limb malalignment, young age, and collateral ligament instability were associated with higher rates of failure.
Meding et al reviewed 39 patients who had bilateral TKA performed following unilateral high tibial osteotomy. There were no differences between the two groups including postoperative complications, range of motion, revision surgery, and patient satisfaction scores.
Parvizi J, Hanssen AD, Spangehl MJ.
J Bone Joint Surg Am. 2004 Mar;86-A(3):474-9. PMID: 14996871 (Link to Abstract)
Meding JB, Keating EM, Ritter MA, Faris PM
J Bone Joint Surg Am. 2000 Sep;82(9):1252-9. PMID: 11005516 (Link to Abstract)
Average 3.0 of 22 Ratings