Patella Fractures: Approach to Treatment

Damayea I. Hargett, MD; Brent R. Sanderson, DO; Milton T.M. Little, MD


J Am Acad Orthop Surg. 2021;29(6):244-253. 

In This Article

Postoperative Management and Rehabilitation

No standard postoperative protocol exists after the surgical treatment of patella fractures. Postoperative protocols allow for immediate weight-bearing in extension using a cylinder cast, knee immobilizer, or hinged knee brace locked in full extension. Initially, the knee range of motion is limited to 0 to 30 degrees for 4 to 6 weeks postoperative. After 4 to 6 weeks, the range of motion is slowly progressed. Early exercise programs should incorporate active flexion with passive extension to allow for motion while minimizing the tensile and bending forces on the repair. After 6 weeks, the patient is allowed to range the knee freely without restrictions.

Each rehabilitation program should be modified to fit each individual case, given patient age, bone quality, fixation type, and fixation stability. In cases of potential patient noncompliance, poor fixation, and partial patellectomy cases, a long leg cast in extension postoperatively should be considered.

It has been postulated that using multiplanar plate fixation may allow for the implementation of earlier ranges of motion, although no high-level clinical literature exists comparing postoperative protocols. Singer et al[38] demonstrated success and no secondary fracture displacement with mesh plating and early range of motion at 2 weeks postoperatively in their series with a mean of 19.6 months follow-up. All study patients except one regained full knee range of motion.

We recommend a simplified approach, which may be modified pending fracture and patient variables. The protocol includes 4 weeks of weight-bearing as tolerated with immobilization in a hinged knee brace locked in extension. Early physiotherapy and initiation of isometric quadriceps exercise programs may begin 2 weeks postoperatively. At the discretion of the surgeon and fixation type, passive and active range of motion may be progressively increased starting at 4 weeks postoperatively. We recommend that a physiotherapist should supervise increases in range of motion. Patients should be allowed to range freely at 6 weeks. Clinical and radiologic signs of healing should be used to advance the patient through the postoperative protocol.

The subcutaneous location of the patella and the demand for early knee motion contribute to the complexity of patella fracture treatment. The reported rates in the literature for hardware removal after patella open reduction and internal fixation vary widely, ranging from 0% to 60%. A meta-analysis investigating the frequency of reoperation, infection, and nonunion after patella fracture fixation reported rates of 33.6%, 3.2%, and 1.3%, respectively.[41] The rate of revision surgery is most commonly secondary to symptomatic hardware. This has led to the evolution in patella fracture fixation and management with suture fixation in tension band constructs. In an effort to decrease postoperative complications, low-profile plating techniques have also progressively improved, which has resulted in lower revision surgery rates reported between 5.9% and 11%.[16,33,34]

Hardware failure is rare after patella fixation, with reported rates from 8% to 12%, in cases managed with screw and Kirschner wire anterior tension band designs.[24] The overall risk of breakage and migration of K-wires is low; however, case reports have been found describing the incident. The fragmented metal pieces can be benign or they can in rare cases migrate to heart.[50] Although this was one rare instance, generally, no distal or proximal migration exists of broken hardware.[51]

Substantial knee extensor weakness has been observed after osteosynthesis partial and total patellectomy. Bayar et al[52] found that patients with >1 mm articular incongruity postoperatively had notably higher incidences of thigh atrophy, pain, and increased physical deficits. The weakness and deficits have been shown to last up to 12 months after surgical fixation. Lazaro et al[40] series reported that 80% of patients treated with tension band fixation reported anterior knee pain during activities of daily living and objective weakness in strength (−41%), power (−47%), and endurance (−34%). 57% of the patients in that cohort had radiographic evidence of patella baja.

Knee arthrofibrosis and loss of knee range of motion is an established complication after patella fracture. Balancing early postoperative range of motion with fracture healing and fracture stability can be challenging and is patient specific. Patients with postoperative limitations in knee flexion may be considered for manipulation under anesthesia and/or arthroscopic lysis of adhesions after fracture union.[53]

The incidence of patellofemoral osteoarthritis is difficult to ascertain from the current literature. Patellofemoral osteoarthritis has been reported in 8.5% of cases treated with tension band wiring technique.[54] The initial injury-related damage to the articular cartilage compared with the quality of reduction as the cause of early onset of post-traumatic osteoarthritis remains unclear.