n Case Report

Patellar Dislocation With Genu Valgum Treated by DFO

Jae Ho Kwon, MD; Jong In Kim, MD; Dong-Hyun Seo, MD; Kyung-Woon Kang, MD; Ji Ho Nam, MD; Kyung-Wook Nha, MD

abstract Full article available online at Healio.com/Orthopedics. Search: 20130523-35

Congenital habitual patellar dislocation is a rare condition of the knee where the pa- tella dislocates during flexion and relocates during extension. The congenital form is permanent, irreducible, and presents at birth. It is characterized by a short quadriceps and a major patellofemoral dysplasia and short height.

This article presents a rare case of a 27-year-old woman with recurring bilateral ha- bitual dislocation of the patella after a failed previous proximal and distal realignment Figure: Preoperative clinical photograph of the pa- procedure. Clinical examinations of both knees revealed genu valgus knees and lateral tient showing valgus knee with previous operation joint pain that recurred after several previous operations. scars.

Radiographs of both knees showed patellar dislocation and genu valgum associated with patellofemoral dysplasia and osteoarthritis of the lateral compartment. Long-leg standing radiographs showed an anatomic tibiofemoral angle of right 13° and left 6° valgus and a mechanical tibiofemoral angle of right 8° and left 2° valgus and weight- bearing line of 65% on the right and 48% on the left.

The authors performed a distal femoral closing wedging osteotomy to correct the val- gus deformity, and then percutaneous lateral release and medial reefing were per- formed to stabilize the patellas of both knees simultaneously.

The authors are from the Department of Orthopaedic Surgery, Inje University, Ilsan Paik Hospital, Ilsan, Korea. The authors have no relevant financial relationships to disclose. Correspondence should be addressed to: Kyung-Wook Nha, MD, 2240, Department of Orthopaedic Surgery, Inje University, Ilsan Paik Hospital, Daehwa-dong, Ilsan-Segu, Koyang-Si, Ilsan, Korea, 411- 706 ([email protected]). doi: 10.3928/01477447-20130523-35

840 ORTHOPEDICS | Healio.com/Orthopedics Bilateral Congenital Habitual Patellar Dislocation | Kwon et al

ongenital habitual dislocation of located immediately after the last opera- angles were 82° and 81° (normal value, the patella is a rare condition and tion, but she did not report any pain. Five 88°63°), respectively; the medial proxi- Ccan be isolated or associated with years after the last surgical procedure, the mal tibial angles were 99° and 102° (nor- other congenital deformities.1 This con- patient presented to the authors’ hospital mal value, 87°63°), respectively; and the dition is usually detected within the first with pain at the lateral compartments in joint congruence angles were 5° and 3° decade of life. Various surgical techniques both knees. Both patellae remained dislo- (normal value range, 0°-2°), respectively. have been introduced to treat the pediatric cated. This confirms valgus deformities of both population, and few have been reported in On physical examination, the knees knees. A skyline radiograph showed com- the adult population.2-4 These techniques had 15° of valgus deformity (Figure 1), plete lateral dislocation of the patella and include proximal soft tissue realignment moderate instability to valgus stress, shallow femoral trochlea on both knees procedures that relocate the patella me- complete lateral dislocation of the patel- (Figure 3). dially, distal realignment procedures that lae, absence of palpable patellofemoral The authors performed a medial clos- transfer the tibia tuberosity medially, or sulcus, and tenderness at the lateral joint ing distal femoral osteotomy with medial total knee arthroplasty (TKA). The au- line. Range of motion was 5° flexion con- reefing to correct valgus deformity, treat thors present a rare case of a 27-year-old tracture to full flexion. She could not fully lateral osteoarthritis, and relocate and sta- woman with bilateral congenital habitual extend either knee. bilize the patellae. dislocation of the patella with lateral os- During radiographic examination, the teoarthritis in genu valgus knee, associ- standing knee radiograph (Figure 2A) ated with patellofemoral dysplasia, that showed moderate arthritic changes on the was treated using a medial closing distal lateral compartment of the right knee that femoral osteotomy followed by percuta- were not observed on the left knee. The neous lateral release and medial reefing. long-leg weight-bearing standing radio- The clinical and radiological outcomes of graph showed a 13° valgus on the right the treatment were successful. knee and 5° valgus on the left knee with depression of the lateral tibia plateau and Case Report a mechanical axis passing outside the A 27-year-old woman (height, 141 lateral compartment (Figure 2B). The cm) presented to the authors’ hospital anatomical lateral distal femoral angles 1 and reported pain in both knee joints. She of the right and left knees were 73° and Figure 1: Preoperative clinical photograph of the pa- stated that her right knee was more pain- 75° (normal value, 81°62°), respective- tient showing valgus knee with previous operation ful than the left knee and that the pain had ly; the mechanical lateral distal femoral scars. persisted for few years. In childhood, her stature was short and both patellae were dislocated bilaterally, but no other abnor- mality was observed in her the hips, spine, and hands. She was previously diagnosed with an atypical form of spondyloepiphy- seal dysplasia. The patient had a history of operations for her knees. At age 16 years, she under- went soft tissue procedures that included lateral release and medial plication for pa- tellar dislocation and tibia lengthening us- ing ilizarov for her short stature. At age 23 years, due to patellar redislocation of both knees that occurred immediately after the first operation, a modified Fulkerson op- 2A 2B eration5 combined with a lateral release Figure 2: Preoperative standing radiographs showing the arthritic changes on lateral compartment of the and medial reefing on both knees, was right knee (A) and long-leg weight-bearing radiograph showing the mechanical axis passing the lateral performed. However, both patellae redis- compartment of the knee joint (B).

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Surgical Technique sels beneath the intermuscular septum ment was checked throughout the full First, a medial closing wedge osteot- were preserved. range of motion, and lateral dislocation of omy of the distal femur was performed. The oblique osteotomy begins in the the patella was no longer observed. The A longitudinal skin incision was made medial supracondylar area and ends with- same procedure was performed for the left beginning 10 cm above the patella and ex- in the lateral femoral condyle. The start- knee. One week postoperatively, leg rais- tending to the apex of the patella distally. ing point for the distal osteotomy at the ing exercises with gradual flexion exercise Using a subvastus approach, the muscle medial femur was marked with electro- were started while the patient was using fascia was incised and the vastus medialis cautery after temporary application of the a controlled brace. Full range of motion muscle was stripped from the intermus- plate. A guide pin was inserted under the was obtained with no evidence of patellar cular septum and retracted proximally. A fluoroscopy, and the osteotomy was cre- instability at postoperative week 4. Partial blunt retractor was passed over the femur ated using an oscillating saw, followed by weight bearing was gradually permitted, to expose the anteromedial aspect of the osteotomes. The osteotomy was created and full weight bearing was permitted at supracondylar area of the femur. The in- up to 10 mm before the lateral cortex, pre- postoperative week 6. termuscular septum in the metaphyseal serving a lateral femoral cortex and creat- Postoperative long-leg weight-bear- area of the femur was carefully incised ing a medially based wedge of the bone ing radiographs and simple radiographs longitudinally, close to the bone. The ves- that was removed. Residual bone frag- showed correction of the valgus defor- ments were removed from the osteotomy. mity (Figure 4) and no evidence of patel- The osteotomy was carefully closed by lar subluxation or dislocation (Figure 5). applying consistent pressure. The align- She was free of pain and had no patellar ment of the axis of the leg was evaluated dislocation. At 1-year follow-up, her Ku- by fluoroscopy. jula score6 was 95, indicating an excellent The osteotomy was stabilized using clinical result. a TomoFix MDP plate (Synthes, West Chester, Pennsylvania). After firm stabi- Discussion 3 lization of the osteotomy, a percutaneous Congenital habitual dislocation of the lateral release was performed, and ap- patella is a well-known but rare condi- Figure 3: Preoperative Merchant radiograph show- 1 ing patellar dislocation and dysplasia of the femo- proximately 1 cm of the medial retinacu- tion. The causes of congenital habitual ral trochlea. lum was reefed. The patellofemoral align- dislocation of the patella are still debated, but they can be present as an isolated in- cident and are sometimes associated with other lower-limb malformations or part of the other congenital syndromes, such as Down’s syndrome, nail-patella, and epiphyseal dysplasia.7 Most patients are diagnosed and treated at an early age; however, treatment for late presentation of congenital dislocation of the patella in adults is controversial.8 Various surgical methods have been used, such as lateral retinacular release, medial reefing, medial patellofemoral ligament reconstruction, modified Fulk-

4A 4B 5A Figure 4: Three-month postoperative long-leg weight-bearing radiograph showing the changes of the Figure 5: Three-month postoperative follow-up mechanical axis after corrective osteotomy (A) and clinical photograph of the patient showing correction merchant radiograph showing no evidence of pa- of the valgus deformity (B). tellar dislocation.

842 ORTHOPEDICS | Healio.com/Orthopedics Bilateral Congenital Habitual Patellar Dislocation | Kwon et al

erson osteotomy, and TKA. The current she was treated by the current authors with thritis in genu valgus knee associated with patient was a young adult with unicom- a medial closing wedge distal femoral os- femoral dysplasia. partmental osteoarthritis who underwent teotomy combined with a medial reefing a distal femoral osteotomy rather than a and lateral release. The surgical procedure References TKA. Osteotomy can be performed us- has resulted in a successful outcome. 1. Storen H. Congenital complete dislocation ing an opened or closed technique, but the of patella causing serious disability in child- hood: the operative treatment. Acta Orthop former has been associated with an incre- Conclusion Scand. 1965; 36(3):301-313. ment of patellofemoral contact pressure, There are several advantages of this 2. Kumagi M, Ikeda S, Uchida K, Ono T, Tsu- use of bone grafts, and collapse due to treatment method for congenital disloca- mara H. Total knee replacement for osteoar- breakage of the far cortex. Medial patel- tion of the patella with genu valgus knee. thritis of the knee with congenital dislocation of the patella. J Bone Joint Surg Br. 2007; lofemoral ligament reconstruction needs a Varus osteotomy in a valgus knee reduc- 89(11):1522-1524. soft tissue, autograft, or allograft for the es a loading pressure by medicalization 3. Shen HC, Chao KH, Huang GS, Pan RY, Lee reconstruction, which is a complicated of the mechanical axis of the lower limb, CH. Combined proximal and distal realign- ment procedures to treat the habitual disloca- surgical procedure. which effectively controls osteoarthrosis tion of the patella in adults. Am J Sports Med. Similar incidences of adult congenital of the lateral compartment.9 Varus os- 2007; 35(12):2101-2108. habitual dislocation of the patella in vari- teotomy may help decrease the risk of 4. Purushothaman B, Agarwal A, Dawson M. ous conditions have been reported. Puru- patellar redislocation for the realigned Posttraumatic chronic patellar dislocation 4 treated by distal femoral osteotomy and me- shothaman et al reported posttraumatic patella because a valgus knee creates a dial patellofemoral ligament reconstruction. chronic patellar dislocation treated by a strong lateral vector causing dislocation Orthopedics. 2012; 35(11):e1668-e1672. distal open-wedge femoral osteotomy and of the patella.10 The patient’s patellofem- 5. Ebinger TP, Boezaart A, Albright JP. Modifica- a medial patellofemoral ligament recon- oral joint may seem more stable due to tions of the Fulkerson osteotomy: a pilot study assessment of a novel technique of dynamic 3 struction. Shen et al reported a combined correction of the valgus moment of the intraoperative determination of the adequacy of proximal soft tissue and distal tibia tuber- femur. Medial closing femoral osteoto- tubercle transfer. Iowa Orthop J. 2007; 27:61-64. osity realignment procedure to treat ha- my and medial reefing can be performed 6. Kujala UM, Jaakkola LH, Koskinen SK, bitual dislocation of the patella in adults. through a single incision, which is more Taimela S, Hurme M, Nelimarkka O. Scor- ing of patellofemoral disorders. Arthroscopy. Kumagi et al2 reported a congenital dislo- cosmetic than the lateral open wedge 1993; 9(2):159-163. cation of the patella with advanced valgus osteotomy with medial reefing, which 7. Paton RW, Kim WY, Bonshahi A. Non trau- osteoarthrosis that was treated with TKA needs 2 incisions. matic dislocation of the patella in children: the case for a dysplastic aetiology. Acta Or- with relocation of the patella using soft The limitation of this study is that it re- thop Belg. 2005; 71(4):435-438. tissue procedures. ports only 1 patient who was followed for a 8. Hudson J, Reddy VR, Krikler SJ. Total knee The current patient had a bilateral con- short period of time. More primary cases arthroplasty for neglected permanent post- genital habitual dislocation of the patella with longer follow-up periods are needed traumatic patellar dislocation: case report. Knee. 2003; 10(2):207-212. with advanced lateral compartment osteo- to assess the efficacy of this procedure. 9. Wang JW, Hsu CC. Distal femoral varus os- arthritis in genu valgus knees associated Medial closing distal femoral osteotomy teotomy for osteoarthritis of the knee. J Bone with femoral trochlear hypoplasia that re- combined with medial reefing is a viable Joint Surg Am. 2005; 87(1):127-133. curred after transfer of the tibia tuberosity treatment option for patients with bilateral 10. Eilert RE. Congenital dislocation of the patel- and several other soft tissue procedures; congenital patella dislocation with osteoar- la. Clin Orthop Relat Res. 2001; (389):22-29.

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